Ссылки про удаление премоляров
Sep. 29th, 2025 12:39 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
healthy_backЯ не знаю одни и те же это исследования из старых постов, или новые. Но сохраню, т.к. она убирает эту инфу. Даже если старая, но отсортированная инфа - это неплохо.
Старые посты:
Список исследований о рассасывании кости и уменьшении воздушных путей после удаления зубов https://healthy-back.livejournal.com/461062.html (https://healthy-back.dreamwidth.org/447536.html)
Что нам известно важное о черепе, челюстях и зубах https://healthy-back.livejournal.com/437703.html (https://healthy-back.dreamwidth.org/425498.html)
Список ссылок https://healthy-back.livejournal.com/477635.html (https://healthy-back.dreamwidth.org/461539.html)
Удаление премоляров, ВНЧС - список статей https://healthy-back.livejournal.com/484722.html )https://healthy-back.dreamwidth.org/467653.html)
Ещё одна статья Карин про ВНЧС (TMJ) и про White Paper https://healthy-back.livejournal.com/485458.html (https://healthy-back.dreamwidth.org/468470.html)
Влияние удаления премоляров на ВНЧС https://healthy-back.livejournal.com/508166.html (https://healthy-back.dreamwidth.org/494357.html)
Влияние удаления премоляров на внешность https://www.sciencedirect.com/science/article/pii/S2468785523003683
Orthodontic treatment involving tooth extraction may potentially affect the nasolabial angle and nasal depth. During treatment planning, it is crucial to consider the potential changes that may occur to the nose and any alterations that may be needed to achieve the desired esthetic outcome.
Research in how extracted or missing teeth (agenesis) affect jaw growth.
https://www.facebook.com/groups/orthodonticmalpracticevictims/posts/1613330642958801/
Effects on Jaw Growth (from Extractions or Agenesis) —
1) Aasheim B., Ogaard B.
Changes in occlusal traits after orthodontic treatment with and without premolar extractions. Eur J Orthod.1993;15(6):501–509.
PubMed
→ Compared extraction vs. non-extraction patients longitudinally. Found extraction cases had reduced arch length and restrained jaw projection, echoing the mechanism seen in agenesis.
2) Bertl M.H., Bertl K., Wagner M., et al.
Second premolar agenesis is associated with mandibular form: a geometric morphometric analysis. Int J Oral Sci.2016;8(4):254–260.
PubMed | Full text
→ CBCT/morphometric: agenesis cases showed smaller mandibular cross-sections and reduced alveolar support.
(https://www.nature.com/articles/ijos201623) → CBCT / morphometric: mandibular cross-sections are narrower/smaller in second-premolar agenesis. Reduced alveolar support limits basal mandibular development.
3) Brézulier D., Raimbault P., Jeanne S., Davit-Béal T., Cathelineau G.
Association between dental agenesis and facial morphology: cross-sectional study in France. PLoS One.2024;19(12):e0314404.
PubMed | Full text
→ Agenesis correlated with maxillary constriction, greater lower facial divergence, and reduced chin projection.
4) Brodie A.G.
On the Growth of the Jaws and the Eruption of the Teeth. Angle Orthod. 1942;12(1):25–40.
DOI
→ Provided growth curves that became the benchmark for later extraction caution. Showed forward mandibular growth potential, which extractions can compromise.
5) De Castro N.
Second-premolar extraction in clinical practice. Am J Orthod. 1974;65(2):115–143.
PubMed
→ Clinical guidance piece, discusses timing of second-premolar extraction relative to growth. Notes that removing teeth during active growth may alter eruption patterns and basal bone development.
6) Dellavia C., Catti F., Sforza C., et al.
Craniofacial growth in ectodermal dysplasia: an eight-year longitudinal study. Head Face Med. 2010;6:18.
PubMed | Full text
→ Longitudinal agenesis cohort: showed alveolar bone deficiency and midfacial undergrowth.
7) Dewel B.F.
Serial extraction in orthodontics: Indications, objectives, and treatment procedures. Am J Orthod. 1954;40(11):906–926.
DOI
→ Introduced serial extraction as systematic protocol—later criticized for blocking forward mandibular growth.
8) Dewel B.F. Serial extraction in orthodontics: Indications, objectives, and treatment procedures. Am J Orthod. 1954;40(11):906–926. DOI → Introduced serial extraction as systematic protocol—later criticized for blocking forward mandibular growth.
Dewel B.F. Serial extraction: its limitations and contraindications in orthodontic treatment. Am J Orthod. 1967;53(12):904–921. DOI → Warned explicitly: backward mandibular rotation and flattened profiles from extractions during growth.
9) Dupré N., Rallo A., et al.
Reduced bone dimension in oligodontia patients: maxillary and mandibular CBCT study. Orthod Craniofac Res.2023;26(4).
DOI
→ Agenesis cases had narrower alveolar dimensions even at dentate sites, confirming jaw development restriction.
10) Graber T.M.
Serial extraction: a continuous diagnostic and decisional process. Am J Orthod. 1971;60(6):541–575.
PubMed
→ Warned that extractions must be growth-sensitive; otherwise they impede jaw development.
11) Hotz R.P.
Guidance of eruption versus serial extraction. Trans Eur Orthod Soc. 1970;46:311–335.
PubMed
→ Advocated eruption guidance; noted that extraction may cause narrow arches and growth restriction.
12) Jurek A., Antoszewska-Smith J., Turp I., et al.
Effect of tooth agenesis on mandibular morphology and position: 3D cephalometric study. Int J Environ Res Public Health. 2021;18(22):11876.
PubMed | Full text
→ Agenesis patients had shorter mandibles and narrower symphyses, consistent with growth restriction.
13) Kjellgren B.
Serial extraction as a corrective procedure in dental orthopedic therapy. Am J Orthod. 1948;34(5):372–379.
DOI
→ First formal proposal of serial extraction. Already noted risk of arch constriction and altered development.
14) Lloyd Z.B.
Serial extraction as a treatment procedure. Angle Orthod. 1956;26(4):291–307.
DOI
→ Protocol emphasizing evaluation of arch length vs. basal bone growth. Noted risk of jaw growth restriction if done prematurely.
15) Norman F.
Serial Extraction. Angle Orthod. 1965;35(1):1–25.
DOI
→ Mid-60s review: cautioned that premature extraction could limit basal bone growth.
16) Oeschger E.S., Eliades T., Papadopoulou A.K., Gkantidis N.
Number of teeth is associated with facial size in humans. Sci Rep. 2020;10:58565.
PubMed | Full text (https://www.nature.com/articles/s41598-020-65376-3)
→ Population study: fewer teeth directly linked to smaller faces.
17) Rachmiel A., Emodi O., et al.
Management of severely atrophic maxilla in EEC syndrome. Case Rep Plast Surg Hand Surg. 2018;5(1).
PubMed | Full text
→ Syndromic agenesis → severe alveolar atrophy and maxillary underdevelopment.
Richardson A. A review of changes in lower arch length. Br J Orthod. 1979;6(3):151–154. PubMed → Arch length naturally declines with age; extractions accelerate the reduction, constraining mandibular development.
18) Ringenberg Q.M.
Influence of serial extraction on growth and development of the maxilla and mandible. Am J Orthod. 1967;53(2):89–102.
DOI
→ Directly measured restricted maxillary/mandibular growth after serial extractions.
19) Ringenberg Q.M.
Serial extraction: Stop, look, and be certain. Am J Orthod. 1964;50(5):328–336.
DOI
→ Famous caution: “After using forceps, there is no turning back.” Reported concave profiles from serial extractions.
20) Schieffer L., Nowak R., May A., et al.
Curve of Spee and second mandibular premolar agenesis—mandibular morphology differences. Appl Sci.2022;12(22):11747.
Full text
→ Agenesis linked to smaller mandibles and altered morphology due to alveolar bone loss.
21) Tweed C.H.
Indications for the extraction of teeth in orthodontic procedure. Am J Orthod Oral Surg. 1944;30(8):405–428.
DOI
→ Landmark paper advocating extractions to reduce protrusion—later criticized for producing flat profiles and altering jaw growth direction.
22) Zierhut E.C., Joondeph D.R., Artun J., Little R.M.
Long-term profile changes associated with premolar extractions. Am J Orthod Dentofacial Orthop. 2000;118(2):91–103.
PubMed
→ Long-term study: extraction patients showed restrained jaw projection and flatter profiles compared to controls.
SYNTHESIS (UNCHANGED MESSAGE YOU REQUESTED)
Agenesis and extractions operate by the same mechanism: fewer teeth → less alveolar bone → restricted jaw growth → flatter profiles.
Historic warnings (Brodie 1942; Tweed 1944; Dewel 1954, 1967; Ringenberg 1964, 1967; Graber 1971; Hotz 1970) anticipated what modern CBCT/morphometric studies (Bertl 2016; Jurek 2021; Schieffer 2022; Brézulier 2024) have quantified.
TMD and Orthodontics: some articles out there
https://www.facebook.com/groups/orthodonticmalpracticevictims/posts/1613167909641741/
1) Dawson P.E. Functional Occlusion: From TMJ to Smile Design. Mosby/Elsevier; 2006/2007.
Elsevier page Elsevier Shop | NLM catalog National Library of Medicine Catalog
→ Authoritative text linking occlusal scheme, guidance, and TMJ loading.
2) Kim Y.H., Han S.S., Kim T.K., et al. Effect of premolar extraction and incisor retraction on TMJ position and morphology: CBCT study. Korean J Orthod. 2019;49(5):310–318. PubMed | PMC
3) Pullinger A.G., Seligman D.A., Gornbein J.A. A multiple logistic regression analysis of the risk and relative odds of temporomandibular disorders as a function of common occlusal features. Am J Orthod Dentofacial Orthop. 1993;103(6):523–530. PubMed
4) Chen Y.J., Yao J.C., Chang Z.C., et al. Premolar extractions and temporomandibular disorder prevalence: a retrospective study. Angle Orthod. 2015;85(6):959–965. PubMed
5) Londoño A., Assis M., Fornai C., Greven M. Premolar Extraction Affects Mandibular Kinematics. Eur J Dent. 2023;17(3):756–764.
PubMed PubMed | PDF Thieme
→ Extraction group showed:
• Increased lateral translations during protrusion–retraction and speech.
• Longer condylar trajectories, more rotation.
• ≥ 25% of cases exhibited altered mandibular kinematics.
Authors conclude extractions modify mandibular motion and warrant TMJ functional evaluation before extraction decisions.
BIBLIO - PER - .FULLdocx
https://www.facebook.com/groups/orthodonticmalpracticevictims/posts/1643435563281642/
Effects of orthodontics on Temporomandibular Joints (TMJ)
1) Artun J., Hollender L.G., Truelove E.L.
Relationship between orthodontic treatment, condylar position, and internal derangement in the temporomandibular joint. Am J Orthod Dentofacial Orthop. 1992;101(1):48–53. https://pubmed.ncbi.nlm.nih.gov/1731488/
→ Tested whether incisor retraction affects condylar position. Post-treatment tomograms showed posteriorly displaced condyles in extraction cases and a higher frequency of TMJ clicking, suggesting posterior repositioning can contribute to joint strain in some patients.
2) Londoño A., Assis M., Fornai C., Greven M.
Premolar Extraction Affects Mandibular Kinematics. Eur J Dent. 2023;17(3):756–764.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10569881/
→ Extraction group showed:
• Increased lateral translations during protrusion-retraction and speech.
• Longer condylar trajectories, more rotation.
• ≥ 25 % of cases exhibited altered mandibular kinematics.
• Authors conclude extractions modify mandibular motion which may be a cause of TMD, and hence a reason to avoid premolar extractions.
3) Okeson J.P., de Leeuw R.
Differential diagnosis of temporomandibular disorders and occlusal correlates. Dent Clin North Am. 1995;39(2):261–285.
https://pubmed.ncbi.nlm.nih.gov/7781299/
→ Notes that loss of posterior support or altered guidance increases TMJ loading; recommends screening before retraction or extraction mechanics. Highlights that occlusal factors—especially loss of posterior support or altered anterior guidance—can increase joint loading and predispose to pain or internal derangement in susceptible patients. The authors emphasize pre-orthodontic screening of joint health prior to major occlusal changes such as retraction or extractions.
4) Wyatt W.E.
Preventing adverse effects on the temporomandibular joint during orthodontic treatment. Am J Orthod Dentofacial Orthop. 1987;91(6):493–499.
https://pubmed.ncbi.nlm.nih.gov/3473929/
→ Warns that over-retraction and loss of posterior support can destabilize the TMJ; advocates force control and condylar monitoring.
ALVEOLAR BONE AND EXTRACTIONS
https://www.facebook.com/groups/orthodonticmalpracticevictims/posts/1613163362975529/
1) Shen Y.W., Hsu J.T., Wang Y.H., Huang H.L., Fuh L.J., Shen Y.W. Evaluation of alveolar bone thickness following orthodontic extraction treatment: A CBCT study. J Dent Sci. 2014;9(3):282–288. ScienceDirect
→ CBCT demonstrated significant alveolar bone loss on the labial side of maxillary incisors after extraction therapy. Retraction led to thinning of the alveolar housing.
1) Jiang J., Hu W., Zhang Y., Chen J. Alveolar bone changes following orthodontic treatment with premolar extractions: A systematic review and meta-analysis. Sci Rep. 2018;8:17036. PubMed | PMC
→ Meta-analysis confirmed alveolar bone loss and dehiscence are more prevalent in extraction cases. Incisor retraction compromises alveolar bone support.
1) Sadek M.M., Sabet N.E., Hassan I.T. Three-dimensional assessment of alveolar bone changes after orthodontic treatment with and without premolar extractions. Am J Orthod Dentofacial Orthop. 2015;148(4):702–710. PubMed
→ 3D imaging shows marked reduction in alveolar bone thickness and height in extraction patients compared to non-extraction controls.
1) Lin L., Ahn H.W., Kim S.H., Chung K.R., Kim K.B., Nelson G. Tooth-bone discrepancy and alveolar bone loss in extraction vs. non-extraction orthodontic therapy: CBCT findings. Angle Orthod. 2014;84(3):400–406. PubMed
→ CBCT analysis: retraction of incisors in extraction cases caused alveolar bone dehiscence and fenestration. Non-extraction cases showed far less alveolar compromise.
1) Ahn H.W., Moon S.C., Baek S.H. Morphometric evaluation of alveolar bone following premolar extraction with maximum retraction. Korean J Orthod. 2013;43(5):272–279. PubMed | PMC
→ Maximum retraction after extraction increases risk of alveolar bone defects and resorption.
SYNTHESIS (FULLER VERSION):
Across CBCT studies, morphometric analyses, and systematic reviews, premolar extraction therapy with incisor retraction is strongly and consistently associated with alveolar bone compromise. The most common findings are:
Labial bone loss and thinning of the alveolar housing around maxillary incisors.
Dehiscence and fenestrations occur more frequently in extraction cases than in non-extraction controls.
Vertical height reduction of alveolar bone is seen after space closure.
Greater incisor retraction = greater risk of alveolar defects, resorption, and compromised periodontal support.
Non-extraction patients tend to maintain or even thicken alveolar bone, while extraction patients demonstrate marked thinning.
Systematic review/meta-analysis (Jiang 2018) confirms that alveolar bone loss is not incidental but a reproducible outcome of extraction-based orthodontics.
Overall, the evidence converges: extractions place incisors outside their natural bony envelope, leading to long-term structural vulnerability of the alveolus.
PREMOLAR EXTRACTION EFFECTS ON THE LIPS AND PROFILE
1) Albertini P., Barbara L., Albertini E., Willeit P., Lombardo L.
Soft-tissue profile changes in adult patients treated with premolar extractions. Am J Orthod Dentofacial Orthop.2024;166(2):171–178.
DOI | PubMed
→ 75 adults: mean lip retraction = 1.4 mm (upper) / 1.7 mm (lower). Thin lips retracted more, producing flatter profiles.
2) Bravo L.A.
Soft tissue facial profile changes after orthodontic treatment with four premolars extracted. Angle Orthod. 1994;64(1):31–42.
DOI | PubMed
→ 16 extraction cases: lips retracted ≈ 3.4 mm (upper) / 3.8 mm (lower) relative to E-line. Naso-labial angle ↑ by ~3.7°. Clear profile flattening.
3)Caplan D.
Soft-tissue changes following orthodontic treatment with premolar extractions. Angle Orthod. 1969;39(4):285–297.
DOI
→ One of the earliest systematic reports: found flattening of upper and lower lips after premolar extractions, with esthetic concerns raised.
4) Change of Lip Curvature Through Extraction and Non-extraction.
Kim B. et al. Appl Sci. 2024;14(24):11715.
Full text
→ Cephalometric study on 62 Class I cases; lip flattening was not always significant even with extraction, though incisor inclination influenced curvature.
5) Drobocky O.B., Smith R.J.
Changes in facial profile during orthodontic treatment with premolar extractions: long-term evaluation. Am J Orthod Dentofacial Orthop. 1989;95(3):220–230.
DOI | PubMed
→ Long-term follow-up: extraction patients had persistent lip retrusion and flattened profiles even years after retention.
6) Ekstam M., Gerstorf K., et al.
Effects of premolar extraction and orthodontic treatment in soft tissue and dental parameters. Acta Odontol Scand. 2023.
Full text
→ In extraction cases, soft tissue profile shows measurable lip retrusion, but variability depends on lip thickness and anchorage.
7) Kocadereli I.
Changes in soft tissue profile after orthodontic treatment with and without extraction. Am J Orthod Dentofacial Orthop.2002;122(1):67–72.
DOI | PubMed
→ Class I patients: extraction group showed more retracted lips and flatter profiles than non-extraction controls.
8) Kochar G.D.
Treatment effects and lip profile changes following extraction. J Orthod Res. 2023;11(2).
PMC
→ RCT in Class II patients: extraction groups showed greater lip retrusion and profile flattening than non-extraction.
9) Janson G., Valarelli F.P., et al. Relationship between maxillary incisor retraction and soft tissue changes. Am J Orthod Dentofacial Orthop. 2007;132(3):281–289. PubMed
→ Large sample confirmed extraction cases show significantly more lip retrusion compared with non-extraction.
10) Lew K.K.
Profile changes following orthodontic treatment of bimaxillary protrusion in adults. Eur J Orthod. 1989;11(4):375–381.
DOI | PubMed
→ Adults with bimax protrusion: 4 premolar extractions + incisor retraction ≈ 5.6 mm (upper) / 4.4 mm (lower). Naso-labial angle increased.
11) Looi L.K., Mills J.R. The effect of orthodontic treatment on the soft-tissue profile. Eur J Orthod. 1986;8(4):255–262. PubMed
→ Premolar extractions led to flattening of the soft-tissue profile compared to non-extraction controls. Changes persisted long-term.
12) Liao Y.F., Huang C.S., Lin J.N. Lip response to maxillary incisor retraction in bimaxillary protrusion patients. Am J Orthod Dentofacial Orthop. 2000;118(2):162–169. PubMed
→ Quantified ratio: ~1 mm of incisor retraction produced ~0.6 mm of upper lip retraction. Extraction therapy thus directly linked to lip
13) Pendse T.A., et al.
Effect of premolar extraction on lip strain and lip length. J Orthod Res. 2025;13(2).
Full text
→ Compared lip strain, thickness, lip fall in patients with incisor retraction + extraction. Found lip fall and strain varied by tissue thickness.
14) Qiao Q., Zhang L., Xie X., Bai Y., Su L.
Structured-light 3D assessment of soft-tissue changes after four-premolar extraction in young adult females. Am J Orthod Dentofacial Orthop. 2024;165(1):80–92.e4.
DOI | PubMed
→ 3D scans: posterior displacement of the upper lip ≈ –1.89 mm vs. controls. Clear flattening.
15) Rains M.D., Nanda R.
Soft-tissue changes associated with maxillary incisor retraction. Am J Orthod. 1982;81(6):481–488.
PubMed
→ Incisor retraction (with extractions) caused upper lip retrusion and reduced vermilion display. Authors emphasized that soft tissue changes were clinically visible and often esthetically undesirable flattening.
16) Riedel R.A.
An analysis of dentofacial relationships. Am J Orthod. 1950;36(4):297–321.
DOI
→ Early foundational cephalometric study. Riedel showed that extraction/retraction flattens lips, warning that excessive retraction may harm esthetics.
17) Sadry S., et al.
Analyzing the effects of tooth extraction on the lip in orthodontic treatment. Orthod Craniofac Res. 2022.
ScienceDirect
→ Extraction cases had reduced vermilion thickness and lip curvature changes, though not always esthetically negative if carefully planned.
18) Sadry S., et al.
Nasal profile changes after orthodontic tooth extraction. Orthod Craniofac Res. 2024.
ScienceDirect
→ Upper-premolar extractions sometimes gave upper lip protraction, while four-premolar extraction caused lower lip retraction; effect varies by extraction pattern.
19) Shen L.H., Xie T.Y., Jiang R.P., et al.
3D changes in lip vermilion after orthodontic extraction in adult females. Head Face Med. 2021;17(1):9.
DOI | PubMed
→ Vermilion surface area reduced by –51 to –70 mm². Clear lip thinning after extraction.
20) Talass M.F., Talass L., Baker R.C.
Soft-tissue profile changes resulting from retraction of maxillary incisors. Am J Orthod Dentofacial Orthop.1987;91(5):385–394.
DOI | PubMed
→ Classic ceph study: incisor retraction increased naso-labial angle.
→ Documented significant lip retraction and flattening after four-premolar extractions. The upper and lower lips retruded in proportion to incisor retraction, altering esthetics.
21) Wholley C.J., et al.
The Effects of Commonly Prescribed Premolar Extraction on Lip Profile. Angle Orthod. 2003;73(4):386–392.
Full text
→ Dental changes (incisor retraction, interincisal angle) correlate strongly with lip profile flattening in extraction protocols.
Synthesis
From Riedel (1950) and Caplan (1969) to modern 3D imaging (Qiao 2024, Pendse 2025), the literature consistently shows that premolar extraction + incisor retraction leads to lip retraction, reduced vermilion, and profile flattening.
Early pioneers (Riedel, Caplan) warned of esthetic risks.
Long-term studies (Drobocky & Smith 1989) confirmed flattening persists.
Recent 3D volumetric research (Shen, Qiao, Albertini) quantifies lip thinning and volume loss.
https://www.facebook.com/groups/1270654792948954/?multi_permalinks=25499855589602203&hoisted_section_header_type=recently_seen
A summary of premolar extraction risks
1) Potential impacts of premolar extractions
Premolar extractions/retractions predictably narrow the dental arches (in length and width) and thus the oral cavity/palate, with a risk of reducing tongue space. This shrinkage of the oral cavity space can lead to swallowing disorders, speech defects, chewing difficulties, tongue discomfort, as well as airway narrowing and breathing disorders.
The literature describes a link between extractions and pharyngeal narrowing/backward displacement of the hyoid bone, factors associated with sleep-disordered breathing (apnea, mouth breathing, snoring).
Airway narrowing can also promote forward head posture, changes in cervical spine curvature, and other postural disorders.
These mechanisms may contribute to systemic symptoms: general fatigue, reduced sports endurance, decreased vocal resonance, eating discomfort, chronic cervico-scapular pain, tachycardia, nervous-system disorders (chronic activation of the “fight-or-flight” mode), immune disorders, hair loss, and other comorbidities, and an overall decrease in quality of life.
The above systemic issues are general summaries from the stats of the survey that has reached 3400 people.
2) Orthodontic camouflage vs skeletal correction
Using extractions to camouflage a skeletal discrepancy (e.g., retruded mandible, narrow palate) does not treat the cause and may worsen initial symptoms. It can also complicate later surgery if such a procedure becomes necessary after the extraction/retraction phase.
The practitioner must:
inform the patient about the potential consequences of extractions (arch narrowing; impact on the tongue/airway/aesthetics) as well as available alternatives.
Put health objectives on the same level as occlusion/aesthetics.
Compare the “extractions/camouflage” option with expansion scenarios and/or skeletal correction/surgery.
Weigh benefits/risks for tongue space, airways, and postural stability.
3) Recommended clinical and paraclinical evaluation (before any extraction decision)
Pre-tx exams:
Airway: dedicated imaging (CBCT/volumetric assessments), nasal endoscopy if indicated
TMJ: clinical exam (masticatory/cervical muscles), imaging if necessary.
Functions: breathing. swallowing, chewing, speech; spinal posture
Myofunctional evaluation of tongue function
4) Current professional trends and caution
The use of premolar extractions has clearly decreased compared with past decades, in Europe and in the U.S., mainly due to aesthetic risks (flattened profile) and also—though to a lesser extent—due to respiratory risks.
However, the profession is not evolving fast enough.
The premolar-extraction rate in 2025 remains far too high.
The global average is estimated at about 50% of all patients undergoing orthodontic treatment. The decision to extract depends on the orthodontist's individual whim> there is no standard protocol for this standard of care.
So for now it is luck of the draw if a patient is extracted "prudently" by a risk-aware orthodontist or by someone who extracts in half their patients as a matter of course.
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https://www.facebook.com/groups/1270654792948954/?multi_permalinks=25509067872014308&hoisted_section_header_type=recently_seen
We often imagine the body as a collection of parts: the jaw, the spine, the hips, the feet. But anatomically and neurologically, these parts belong to a single kinetic chain. A change in one link inevitably affects the others. Understanding these connections reshapes how we see posture, balance, and even breathing.
1. THE BODY AS A CHAIN OF MOVEMENT
When we move, force and motion travel through the body along what researchers call kinematic chains — a term describing how bones and muscles transmit movement from one joint to another. The body’s design ensures stability and fluidity: each motion of the limbs requires a coordinated counter-motion elsewhere to maintain balance.
In human gait, for example, when the right leg moves forward, the right arm naturally swings backward. This is not a random reflex — it is a built-in neurological and mechanical strategy for maintaining equilibrium. The phenomenon, long observed in biomechanics, is orchestrated by central pattern generators (CPGs) in the spinal cord — neural circuits that synchronize the rhythm of arm and leg movements (Nature 2024). This cross-patterned rhythm stabilizes the trunk and conserves energy as we walk.
Yet the choreography extends beyond arms and legs. Subtle rotations of the pelvis, spine, shoulders, and headaccompany each stride, keeping our eyes level and our balance intact. These coordinated counter-rotations form what yoga, osteopathy, and martial traditions have long recognized: movement is not isolated but whole-body intelligence.
2. THE MANDIBLE’S HIDDEN ROLE
Although the jaw’s main task is chewing and speech, it is structurally anchored into the cranium and cervical spine, which means that any change in head or neck position influences the mandible — and vice versa.
The temporomandibular joint (TMJ) connects the jaw to the skull and is supported by powerful muscles — the masseter, temporalis, pterygoids, and the suprahyoid and infrahyoid groups. These muscles blend seamlessly into the neck’s deep stabilizers, such as the sternocleidomastoid and trapezius. When the mandible shifts laterally or opens, it subtly recruits and rebalances these cervical muscles, leading to micro-adjustments in the thorax and shoulder girdle.
This linkage has been documented in studies showing coordinated motion between jaw, head, and neck. One classic experiment on integrated jaw and neck function found that opening or moving the jaw invariably involves synchronized head–neck adjustments (ResearchGate). The authors described the body as a “kinematically linked” system — where the jaw never acts alone.
3. JAW MOTION DURING WALKING
Surprisingly, even walking involves the mandible.
A study titled Control of Human Mandibular Posture During Locomotion measured micro-movements of the jaw while subjects walked and hopped. Each heel strike produced a slight downward movement of the mandible — a reflex response that helps stabilize the head and dissipate vibration. During normal gait, these displacements were tiny but rhythmic, synchronized with each step (PubMed).
Osteopaths and posturologists have long observed this phenomenon qualitatively: as we walk, the jaw swings gently left and right, mirroring the body’s alternating load between legs. This is not a defect or compensation but part of the body’s finely tuned equilibrium. The mandible thus participates in the same oscillatory rhythm as the pelvis and shoulders, ensuring that sensory inputs — visual, vestibular, and proprioceptive — remain harmonized.
4. PELVIS, SHOULDERS, AND MANDIBLE: A RHYTHMIC DIALOGUE
During each gait cycle:
The right leg advances; the right hip moves forward.
Simultaneously, the right shoulder retracts, counter-balancing the trunk’s rotation.
The spine twists slightly, maintaining the head’s forward orientation.
The neck executes a fine counter-rotation to keep the gaze stable.
The mandible follows suit with micro-oscillations that mirror this rhythm.
This is an engineered dance of stability: every movement above the pelvis compensates and balances for those below. It’s why a misalignment in the foot, knee, or hip can propagate upward, eventually disturbing the head’s balance or the jaw’s resting position.
Conversely, a shift in the jaw or cranial base can ripple downward, influencing pelvic orientation and gait.
Osteopathic and postural medicine recognize these chains. Posturologists describe the stomatognathic system (the functional unit of teeth, jaws, and associated muscles) as a critical component of the body’s postural control network (PMC Review). Disturbances in bite or jaw alignment can alter head posture, which in turn shifts the body’s center of gravity and muscular tone along the spine, pelvis, and lower limbs.
5. A UNIFIED ENGINEERING
Seen through this lens, human movement resembles a well-tuned mechanical orchestra more than a set of disconnected levers. The gait cycle, breathing rhythm, and mandibular balance are all synchronized by the nervous system’s pursuit of equilibrium and efficiency.
When these relationships are disrupted — through injury, poor posture, dental malocclusion, or even stress — the resulting imbalance can cascade through the system, affecting areas seemingly far away from the source. This is why practices such as yoga, tai chi, and osteopathy emphasize global awareness: freedom in one joint depends on harmony in all the others.
In essence, the mandible does not just chew or speak; it participates in the living rhythm of the body. Each step, each breath, each subtle sway of the hips and shoulders is echoed — quietly — in the movement of the jaw.
(All links verified October 2025)
https://www.facebook.com/groups/extractionorthodonticsreversal/posts/25716594297928330/
Premolar Extractions and the Loss of Masticatory Efficiency
1) Chewing performance in orthodontic patients treated with extraction of premolars. J Chosun Obr. 2019; 43(3):196–203.
https://www.chosunobr.org/journal/download_pdf.php?doi=10.21851%2Fobr.43.03.201909.196
→ Direct extraction study comparing pre- and post-treatment masticatory function. Patients with premolar extractions showed shorter, slower chewing cycles and reduced efficiency versus baseline. Indicates that orthodontic extractions impair chewing kinetics, especially with narrowed arch form.
2) English J.D., Buschang P.H., Throckmorton G.S.
Does malocclusion affect masticatory performance? Angle Orthod. 2002; 72(1):21–27.
https://pubmed.ncbi.nlm.nih.gov/11881753/
→ Established that malocclusions—including those created by retractive mechanics—significantly reduce chewing efficiency, yielding larger bolus particle size and decreased breakdown rate.
3) Fathalla R., Samih H.M., Ramadan A.A.
Assessment of occlusal forces in patients treated with four first-premolar extractions: An in vivo study using the T-Scan III system. Dent Stud. 2023; 5(1):70-76.
https://pubmed.ncbi.nlm.nih.gov/38034277/→ Ten adolescent patients treated with four-premolar extractions showed reduced anterior bite-force contribution and slight posterior redistribution. Overall occlusal force balance achieved, but anterior functional weakness persisted, suggesting compensatory rather than normal adaptation.
4) Haraldson T., Carlsson G.E., Ingervall B.
Functional state of the masticatory system in denture and natural dentition subjects. Acta Odontol Scand. 1979; 37(6):333–341.
https://pubmed.ncbi.nlm.nih.gov/294451/
→ Classic physiologic reference: demonstrated that reduced dental arches or missing teeth sharply decrease bite-force and chewing efficiency. Provides the foundational evidence that smaller dental arches—whether edentulous or extraction-induced—mean weaker mastication.
5) Helkimo E., Ingervall B., Carlsson G.E.
Bite force and functional state of the masticatory system in young adults. Swed Dent J. 1971; 64(3):153–160.
https://pubmed.ncbi.nlm.nih.gov/5285249/
→ Measured normal bite-force in young adults and correlated it with occlusal contact area. Found that bite-force decreases linearly with loss of posterior support—a principle directly relevant to orthodontic extractions.
6) Kohyama K., Mioche L., Martin J.F.
Chewing patterns of subjects with occlusal disharmonies. Arch Oral Biol. 2002; 47(6):461–471.
https://pubmed.ncbi.nlm.nih.gov/12000302/
→ Subjects with narrow arches and occlusal disharmonies (often post-extraction) exhibited longer, less efficient chewing cycles and maladaptive muscular coordination. Supports the link between arch constriction and functional decline.
7) Miura H., Araki Y., Morita M.
Relationship between occlusal contact area and bite-force in adults. J Oral Rehabil. 1981; 8(5):465–471.
https://pubmed.ncbi.nlm.nih.gov/6945325/
→ Quantified bite-force as a direct function of occlusal contact area. Showed that any reduction in arch width or tooth number lowers maximal bite-force, forming the physiologic basis for extraction-related weakness.
8) Peyron M.A., Lassauzay C., Woda A.
Effects of dental and prosthetic status on masticatory performance. J Dent Res. 2002; 81(8):545–549.
https://pubmed.ncbi.nlm.nih.gov/12215566/
→ Demonstrated that fewer functional teeth and reduced occlusal surface area yield lower masticatory output, confirming the mechanical cost of arch reduction.
9) Scientific Reports (Open Access).
Changes in occlusal function after extraction of premolars: A two-year follow-up study. Sci Rep. 2021; 11:8357216.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8357216/
→ Two-year follow-up of non-extraction vs. two- and four-premolar extraction groups. Occlusal contact area and bite-force fell sharply after treatment; only partial recovery at 24 months. Four-premolar group never regained baseline force, confirming persistent mechanical deficit.
10) Shinogaya T., Adachi A., Watanabe M.
Effects of occlusal condition on masticatory efficiency. J Oral Rehabil. 1999; 26(9):739–745.
https://pubmed.ncbi.nlm.nih.gov/10511269/
→ Showed that reducing the number of active occlusal contacts markedly impairs masticatory efficiency. The findings parallel post-extraction occlusal conditions and validate their functional impact.
SYNTHESIS
· Premolar extractions reduce occlusal contact area, arch width, and anterior bite-force, resulting in slower, less efficient chewing and maladaptive muscle patterns.
· Foundational bite-force studies (Helkimo 1971; Haraldson 1979; Miura 1981) established that any loss of dental units or arch constriction directly weakens masticatory power.
· Modern clinical studies confirm extraction patients experience longer chewing cycles, smaller bolus breakdown, and incomplete recovery of occlusal function over time.
· Functional adaptations may partially compensate but at the expense of efficiency and possibly joint over-use.
PUBMED.NCBI.NLM.NIH.GOV
Results of biomonitoring analyses in Biomonitoring Laboratory, Helsinki, Finland in 1997 - PubMed
In 1997 a total of 4848 results of 47 different analytes from blood or urine specimens, were performed in the Finnish Institute of Occupational Health, Biomonitoring Laboratory, Helsinki, Finland. The results of these service analyses were registered in a database with additional information concern...
https://www.facebook.com/groups/extractionorthodonticsreversal/posts/25716125001308593/
Effects of Premolar Extractions on Alveolar Bone (Remodeling and Loss)
1) Sarikaya S., Haydar B., Ciger S., Ariyurek M.
Changes in alveolar bone thickness due to retraction of anterior teeth.
Am J Orthod Dentofac Orthop. 2002;122(1):15–26.
[DOI] [PubMed] [Google Scholar]
→ Demonstrated thinning of the labial cortical plate (~1–2 mm) following anterior tooth retraction; risk of dehiscence in thin alveolar biotypes.
2) Lund H., Grondahl K., Grondahl H.G.
Cone beam computed tomography evaluations of marginal alveolar bone before and after orthodontic treatment combined with premolar extractions.
Eur J Oral Sci. 2012;120(3):201–211.
[DOI] [PubMed] [Google Scholar]
→ CBCT analysis revealed measurable loss of marginal alveolar bone height and thickness on both labial and lingual aspects after extraction space closure.
3) Sun Q., Lu W., Zhang Y., Peng L., Chen S., Han B.
Morphological changes of the anterior alveolar bone due to retraction of anterior teeth: a retrospective study.
Head Face Med. 2021;17(1):30.
[DOI] [PMC:8284009]
→ Quantified anterior plate thinning of ~1.0–1.5 mm depending on retraction magnitude; stresses importance of torque control.
4) Hassan S., Shaikh A., Fida M.
Effect of incisor inclination changes on Cephalometric points A and B.
J Ayub Med Coll Abbottabad. 2015;27(2):268–273.
[PubMed] [Google Scholar]
→ Cephalometric correlation between incisor retraction, alveolar housing change, and sagittal displacement of points A and B.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8284009/?fbclid=IwY2xjawNrRANleHRuA2FlbQIxMABicmlkETF6SzZlT3ZiNkFmb3BaTk92AR4zQDDuKCWE2bDpi54aa4JY3cTV9kpI0Wi56xx3TfR87ECCol_CKXNPFmhS3g_aem_vBBPvLiLpOUuZWTvLd3tmg
Sun Q, Lu W, Zhang Y, Peng L, Chen S, Han B. Morphological changes of the anterior alveolar bone due to retraction of anterior teeth: a retrospective study. Head Face Med. 2021 Jul 16;17(1):30. doi: 10.1186/s13005-021-00277-z. PMID: 34271939; PMCID: PMC8284009.
Synthesis:
Evidence from cephalometric and CBCT studies shows that premolar extractions with anterior retraction—and, in non-extraction contexts, large faciolingual movements without adequate torque control—affect the anterior alveolar housing. Retraction and root proximity to cortical plates are associated with thinning of the labial (and/or palatal) cortical plate, and in thin biotypes, with dehiscence/fenestrations. Quantitatively, Sarikaya et al. (2002) reported labial plate decreases of approximately 1–2 mm after incisor retraction; Lund et al. (2012) showed measurable marginal alveolar bone loss on both labial and lingual sides after extraction space closure on CBCT; and Sun et al. (2021) found anterior plate thinning of roughly 1.0–1.5 mm depending on the degree of retraction. Overall, alveolar remodeling appears unfavorable when movements push roots against cortical boundaries.
https://www.facebook.com/groups/extractionorthodonticsreversal/posts/25746248661629560/
https://academic.oup.com/ejo/article-abstract/27/6/585/400867
A comparative study of dental arch widths: extraction and non-extraction treatment.
Fulya Işık, Korkmaz Sayınsu, Didem Nalbantgil, Tülin Arun
European Journal of Orthodontics, Volume 27, Issue 6, December 2005, Pages 585–589, https://doi.org/10.1093/ejo/cji057
Published: 28 October 2005
https://pmc.ncbi.nlm.nih.gov/articles/PMC10943680/
J Clin Exp Dent. 2024 Feb 1;16(2):e137–e144. doi: 10.4317/jced.61064
Effect of orthodontic premolar extraction on maxillary teeth angulation and arch dimensions in adolescent patients: A 3-D digital model analysis
Ahmed Abohabib 1,✉, Maria J Viñas 2, Josep M Ustrell 3 PMCID: PMC10943680 PMID: 38496807
Dental arches shrink after premolar extractions, both in width and in length.
In adolescents, not only do dental arches shrink they grow less, due to the loss of alveolar bone and the retraction, than in non-extracted adolescents:
Growth in adolescents age 12-14 with palate expansion and no extractions: 4 mm wider arches.
Growth in adolescents 12-14 with no extractions. 2.5mm wider arches.
Growth in adolescents 12-14 with premolar extractions. Negative ,8 mm. They grow "less" at a time when every bone in their body is growing more.
(Note that some articles report that the width between canines INCREASE after premolar extractions. This is true. But do not get your hopes out. One of the studies has the integrity to mention that this is NOT real increase. The canine has been pushed back to the missing premolar space, where it has a wider area. The actual inter-canine space--where the canine once was--has shrunk.
https://www.facebook.com/groups/1270654792948954/?multi_permalinks=25783237691263990&hoisted_section_header_type=recently_seen
Fascinating recent study on how the nose, lip, and philtrum change with premolar extraction.. The nose gets longer, and the philtrum/lip get flatter, with the nasolingual angle steepening about 6.6 degrees. The charts are really detailed. It is controversial that they conclude that the potential adverse profile changes with premolar extractions in ADULTS is more significant than in children--and that the nose changes is a risk that orthodontists should take into cosideration..
Sadry et al., 2024 — “Nasal profile changes after orthodontic tooth extraction in adults”
Non-extraction cases showed a decrease in NLA, while extraction cases showed an increase in NLA.
Full text/abstract: https://www.sciencedirect.com/science/article/pii/S2468785523003683
Note that the public may have the misconception that the "lips" is that red thing (lip vermillion) we commonly call lips. The upper lip is defined anatomically as the muscle that includes the entire area from the base of the nose to the end of the vermillion aka philtrum. . It is not just the "red part" that flattens with upper premolar extractions, it is the philtrum.
Here is AI's explanation of lips:
Key anatomical details:
- The upper lip includes (in its midline) the groove called the Philtrum, which extends from the subnasale (base of the nose) to the upper vermilion border. elementsofmorphology.nih.gov+1
- The surface of the lip region comprises (from outside inward): normal facial skin at its superior or lateral boundary, the vermilion border and vermilion zone (the reddish portion) and then the oral mucosa on the inside. elementsofmorphology.nih.gov+1
- The lips serve many functions: speech articulation (labial, bilabial sounds), food intake (sealing, sucking), facial expression (smile, pucker) and tactile/erogenous sensation. Wikipedia
Therefore in the context of soft-tissue profile changes, when you refer to “the lip” you are referring to the upper border of the oral aperture, including the vermilion zone of the upper lip and the groove above (the philtrum) leading to the base of the nose.
-----
Do orthodontists when they explain the phenomenon of predictable lip flattening with extractions explain how the lip is defined, or are patients led to understand that only the lip vermillion (red part) is affected (hence a minor change)? How about the changes to the nose?
Effects of Premolar Extractions or Agenesis on Jaw/Facial Growth in Growing Patients
Bertl M.H., Bertl K., Wagner M., et al. Second premolar agenesis is associated with mandibular form: a geometric morphometric analysis. Int J Oral Sci. 2016;8(4):254–260. PubMed | Full text (https://www.nature.com/articles/ijos201623) → CBCT / morphometric: mandibular cross-sections are narrower/smaller in second-premolar agenesis. Reduced alveolar support limits basal mandibular development.
Brézulier D., Raimbault P., Jeanne S., Davit-Béal T., Cathelineau G. Association between dental agenesis and facial morphology: cross-sectional study in France. PLoS One. 2024;19(12):e0314404. PubMed | Full text → Agenesis correlated with maxillary constriction, greater lower facial divergence, and reduced chin projection.
Brodie A.G. On the Growth of the Jaws and the Eruption of the Teeth. Angle Orthod. 1942;12(1):25–40. DOI → Provided growth curves that became the benchmark for later extraction caution. Showed forward mandibular growth potential, which premolar extractions can compromise.
De Castro N. Second-premolar extraction in clinical practice. Am J Orthod. 1974;65(2):115–143. PubMed → Clinical guidance piece, discusses timing of second-premolar extraction relative to growth. Notes that removing teeth during active growth may alter eruption patterns and basal bone development.
Dellavia C., Catti F., Sforza C., et al. Craniofacial growth in ectodermal dysplasia: an eight-year longitudinal study. Head Face Med. 2010;6:18. PubMed | Full text → Longitudinal agenesis cohort: showed alveolar bone deficiency and midfacial undergrowth.
Dewel B.F. Serial extraction in orthodontics: Indications, objectives, and treatment procedures. Am J Orthod. 1954;40(11):906–926. DOI → Introduced serial extraction as systematic protocol—later criticized for blocking forward mandibular growth.
Dewel B.F. Serial extraction: its limitations and contraindications in orthodontic treatment. Am J Orthod. 1967;53(12):904–921. DOI → Warned explicitly: backward mandibular rotation and flattened profiles from extractions during growth.
Dupré N., Rallo A., et al. Reduced bone dimension in oligodontia patients: maxillary and mandibular CBCT study. Orthod Craniofac Res. 2023;26(4). DOI → Agenesis cases had narrower alveolar dimensions even at dentate sites, confirming jaw development restriction.
Graber T.M. Serial extraction: a continuous diagnostic and decisional process. Am J Orthod. 1971;60(6):541–575. PubMed → Warned that extractions must be growth-sensitive; otherwise they impede jaw development.
Hotz R.P. Guidance of eruption versus serial extraction. Trans Eur Orthod Soc. 1970;46:311–335. PubMed → Advocated eruption guidance; noted that extraction may cause narrow arches and growth restriction.
Jurek A., Antoszewska-Smith J., Turp I., et al. Effect of tooth agenesis on mandibular morphology and position: 3D cephalometric study. Int J Environ Res Public Health. 2021;18(22):11876. PubMed | Full text → Agenesis patients had shorter mandibles and narrower symphyses, consistent with growth restriction.
Kjellgren B. Serial extraction as a corrective procedure in dental orthopedic therapy. Am J Orthod. 1948;34(5):372–379. DOI → First formal proposal of serial extraction. Already noted risk of arch constriction and altered development.
Lloyd Z.B. Serial extraction as a treatment procedure. Angle Orthod. 1956;26(4):291–307. DOI → Protocol emphasizing evaluation of arch length vs. basal bone growth. Noted risk of jaw growth restriction if done prematurely.
Norman F. Serial Extraction. Angle Orthod. 1965;35(1):1–25. DOI → Mid-60s review: cautioned that premature extraction could limit basal bone growth.
Oeschger E.S., Eliades T., Papadopoulou A.K., Gkantidis N. Number of teeth is associated with facial size in humans. Sci Rep. 2020;10:58565. PubMed | Full text (https://www.nature.com/articles/s41598-020-65376-3) → Population study: fewer teeth directly linked to smaller faces.
Rachmiel A., Emodi O., et al. Management of severely atrophic maxilla in EEC syndrome. Case Rep Plast Surg Hand Surg. 2018;5(1). PubMed | Full text → Syndromic agenesis → atrophic maxillae, underscoring the role of teeth in maintaining alveolar/jaw development.
Richardson A. A review of changes in lower arch length. Br J Orthod. 1979;6(3):151–154. PubMed → Arch length naturally declines with age; extractions accelerate the reduction, constraining mandibular development.
Ringenberg Q.M. Serial extraction: Stop, look, and be certain. Am J Orthod. 1964;50(5):328–336. DOI → Controlled St. Louis study (1954–1959): delayed forward mandibular growth, flatter/concave profiles with incisor retraction. Famous line: “After using forceps, there is no turning back.”
Ringenberg Q.M. Influence of serial extraction on growth and development of the maxilla and mandible. Am J Orthod. 1967;53(2):89–102. DOI → Directly measured restricted maxillary/mandibular growth after serial extractions.
Schieffer L., Nowak R., May A., et al. Curve of Spee and second mandibular premolar agenesis—mandibular morphology differences. Appl Sci. 2022;12(22):11747. Full text → Agenesis linked to smaller mandibles and altered morphology; mechanism: alveolar bone deficiency.
Tweed C.H. Indications for the extraction of teeth in orthodontic procedure. Am J Orthod Oral Surg. 1944;30(8):405–428. DOI → Landmark paper advocating extractions to reduce protrusion—later criticized for producing flat profiles and altering jaw growth direction.
Zierhut E.C., Joondeph D.R., Artun J., Little R.M. Long-term profile changes associated with premolar extractions. Am J Orthod Dentofacial Orthop. 2000;118(2):91–103. PubMed → Long-term follow-up: extraction patients show restrained jaw projection and flatter profiles vs. non-extraction.
Synthesis
Agenesis and extractions operate by the same mechanism: fewer teeth → less alveolar bone → restricted jaw growth → flatter profiles. Historic warnings (Brodie 1942; Tweed 1944; Dewel 1954, 1967; Ringenberg 1964, 1967; Graber 1971; Hotz 1970) anticipated what modern CBCT/morphometric studies (Bertl 2016; Jurek 2021; Schieffer 2022; Brézulier 2024) have quantified.
Старые посты:
Список исследований о рассасывании кости и уменьшении воздушных путей после удаления зубов https://healthy-back.livejournal.com/461062.html (https://healthy-back.dreamwidth.org/447536.html)
Что нам известно важное о черепе, челюстях и зубах https://healthy-back.livejournal.com/437703.html (https://healthy-back.dreamwidth.org/425498.html)
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Удаление премоляров, ВНЧС - список статей https://healthy-back.livejournal.com/484722.html )https://healthy-back.dreamwidth.org/467653.html)
Ещё одна статья Карин про ВНЧС (TMJ) и про White Paper https://healthy-back.livejournal.com/485458.html (https://healthy-back.dreamwidth.org/468470.html)
Влияние удаления премоляров на ВНЧС https://healthy-back.livejournal.com/508166.html (https://healthy-back.dreamwidth.org/494357.html)
Влияние удаления премоляров на внешность https://www.sciencedirect.com/science/article/pii/S2468785523003683
Orthodontic treatment involving tooth extraction may potentially affect the nasolabial angle and nasal depth. During treatment planning, it is crucial to consider the potential changes that may occur to the nose and any alterations that may be needed to achieve the desired esthetic outcome.
https://www.facebook.com/groups/orthodonticmalpracticevictims/posts/1613330642958801/
Effects on Jaw Growth (from Extractions or Agenesis) —
1) Aasheim B., Ogaard B.
Changes in occlusal traits after orthodontic treatment with and without premolar extractions. Eur J Orthod.1993;15(6):501–509.
PubMed
→ Compared extraction vs. non-extraction patients longitudinally. Found extraction cases had reduced arch length and restrained jaw projection, echoing the mechanism seen in agenesis.
2) Bertl M.H., Bertl K., Wagner M., et al.
Second premolar agenesis is associated with mandibular form: a geometric morphometric analysis. Int J Oral Sci.2016;8(4):254–260.
PubMed | Full text
→ CBCT/morphometric: agenesis cases showed smaller mandibular cross-sections and reduced alveolar support.
(https://www.nature.com/articles/ijos201623) → CBCT / morphometric: mandibular cross-sections are narrower/smaller in second-premolar agenesis. Reduced alveolar support limits basal mandibular development.
3) Brézulier D., Raimbault P., Jeanne S., Davit-Béal T., Cathelineau G.
Association between dental agenesis and facial morphology: cross-sectional study in France. PLoS One.2024;19(12):e0314404.
PubMed | Full text
→ Agenesis correlated with maxillary constriction, greater lower facial divergence, and reduced chin projection.
4) Brodie A.G.
On the Growth of the Jaws and the Eruption of the Teeth. Angle Orthod. 1942;12(1):25–40.
DOI
→ Provided growth curves that became the benchmark for later extraction caution. Showed forward mandibular growth potential, which extractions can compromise.
5) De Castro N.
Second-premolar extraction in clinical practice. Am J Orthod. 1974;65(2):115–143.
PubMed
→ Clinical guidance piece, discusses timing of second-premolar extraction relative to growth. Notes that removing teeth during active growth may alter eruption patterns and basal bone development.
6) Dellavia C., Catti F., Sforza C., et al.
Craniofacial growth in ectodermal dysplasia: an eight-year longitudinal study. Head Face Med. 2010;6:18.
PubMed | Full text
→ Longitudinal agenesis cohort: showed alveolar bone deficiency and midfacial undergrowth.
7) Dewel B.F.
Serial extraction in orthodontics: Indications, objectives, and treatment procedures. Am J Orthod. 1954;40(11):906–926.
DOI
→ Introduced serial extraction as systematic protocol—later criticized for blocking forward mandibular growth.
8) Dewel B.F. Serial extraction in orthodontics: Indications, objectives, and treatment procedures. Am J Orthod. 1954;40(11):906–926. DOI → Introduced serial extraction as systematic protocol—later criticized for blocking forward mandibular growth.
Dewel B.F. Serial extraction: its limitations and contraindications in orthodontic treatment. Am J Orthod. 1967;53(12):904–921. DOI → Warned explicitly: backward mandibular rotation and flattened profiles from extractions during growth.
9) Dupré N., Rallo A., et al.
Reduced bone dimension in oligodontia patients: maxillary and mandibular CBCT study. Orthod Craniofac Res.2023;26(4).
DOI
→ Agenesis cases had narrower alveolar dimensions even at dentate sites, confirming jaw development restriction.
10) Graber T.M.
Serial extraction: a continuous diagnostic and decisional process. Am J Orthod. 1971;60(6):541–575.
PubMed
→ Warned that extractions must be growth-sensitive; otherwise they impede jaw development.
11) Hotz R.P.
Guidance of eruption versus serial extraction. Trans Eur Orthod Soc. 1970;46:311–335.
PubMed
→ Advocated eruption guidance; noted that extraction may cause narrow arches and growth restriction.
12) Jurek A., Antoszewska-Smith J., Turp I., et al.
Effect of tooth agenesis on mandibular morphology and position: 3D cephalometric study. Int J Environ Res Public Health. 2021;18(22):11876.
PubMed | Full text
→ Agenesis patients had shorter mandibles and narrower symphyses, consistent with growth restriction.
13) Kjellgren B.
Serial extraction as a corrective procedure in dental orthopedic therapy. Am J Orthod. 1948;34(5):372–379.
DOI
→ First formal proposal of serial extraction. Already noted risk of arch constriction and altered development.
14) Lloyd Z.B.
Serial extraction as a treatment procedure. Angle Orthod. 1956;26(4):291–307.
DOI
→ Protocol emphasizing evaluation of arch length vs. basal bone growth. Noted risk of jaw growth restriction if done prematurely.
15) Norman F.
Serial Extraction. Angle Orthod. 1965;35(1):1–25.
DOI
→ Mid-60s review: cautioned that premature extraction could limit basal bone growth.
16) Oeschger E.S., Eliades T., Papadopoulou A.K., Gkantidis N.
Number of teeth is associated with facial size in humans. Sci Rep. 2020;10:58565.
PubMed | Full text (https://www.nature.com/articles/s41598-020-65376-3)
→ Population study: fewer teeth directly linked to smaller faces.
17) Rachmiel A., Emodi O., et al.
Management of severely atrophic maxilla in EEC syndrome. Case Rep Plast Surg Hand Surg. 2018;5(1).
PubMed | Full text
→ Syndromic agenesis → severe alveolar atrophy and maxillary underdevelopment.
Richardson A. A review of changes in lower arch length. Br J Orthod. 1979;6(3):151–154. PubMed → Arch length naturally declines with age; extractions accelerate the reduction, constraining mandibular development.
18) Ringenberg Q.M.
Influence of serial extraction on growth and development of the maxilla and mandible. Am J Orthod. 1967;53(2):89–102.
DOI
→ Directly measured restricted maxillary/mandibular growth after serial extractions.
19) Ringenberg Q.M.
Serial extraction: Stop, look, and be certain. Am J Orthod. 1964;50(5):328–336.
DOI
→ Famous caution: “After using forceps, there is no turning back.” Reported concave profiles from serial extractions.
20) Schieffer L., Nowak R., May A., et al.
Curve of Spee and second mandibular premolar agenesis—mandibular morphology differences. Appl Sci.2022;12(22):11747.
Full text
→ Agenesis linked to smaller mandibles and altered morphology due to alveolar bone loss.
21) Tweed C.H.
Indications for the extraction of teeth in orthodontic procedure. Am J Orthod Oral Surg. 1944;30(8):405–428.
DOI
→ Landmark paper advocating extractions to reduce protrusion—later criticized for producing flat profiles and altering jaw growth direction.
22) Zierhut E.C., Joondeph D.R., Artun J., Little R.M.
Long-term profile changes associated with premolar extractions. Am J Orthod Dentofacial Orthop. 2000;118(2):91–103.
PubMed
→ Long-term study: extraction patients showed restrained jaw projection and flatter profiles compared to controls.
SYNTHESIS (UNCHANGED MESSAGE YOU REQUESTED)
Agenesis and extractions operate by the same mechanism: fewer teeth → less alveolar bone → restricted jaw growth → flatter profiles.
Historic warnings (Brodie 1942; Tweed 1944; Dewel 1954, 1967; Ringenberg 1964, 1967; Graber 1971; Hotz 1970) anticipated what modern CBCT/morphometric studies (Bertl 2016; Jurek 2021; Schieffer 2022; Brézulier 2024) have quantified.
https://www.facebook.com/groups/orthodonticmalpracticevictims/posts/1613167909641741/
1) Dawson P.E. Functional Occlusion: From TMJ to Smile Design. Mosby/Elsevier; 2006/2007.
Elsevier page Elsevier Shop | NLM catalog National Library of Medicine Catalog
→ Authoritative text linking occlusal scheme, guidance, and TMJ loading.
2) Kim Y.H., Han S.S., Kim T.K., et al. Effect of premolar extraction and incisor retraction on TMJ position and morphology: CBCT study. Korean J Orthod. 2019;49(5):310–318. PubMed | PMC
3) Pullinger A.G., Seligman D.A., Gornbein J.A. A multiple logistic regression analysis of the risk and relative odds of temporomandibular disorders as a function of common occlusal features. Am J Orthod Dentofacial Orthop. 1993;103(6):523–530. PubMed
4) Chen Y.J., Yao J.C., Chang Z.C., et al. Premolar extractions and temporomandibular disorder prevalence: a retrospective study. Angle Orthod. 2015;85(6):959–965. PubMed
5) Londoño A., Assis M., Fornai C., Greven M. Premolar Extraction Affects Mandibular Kinematics. Eur J Dent. 2023;17(3):756–764.
PubMed PubMed | PDF Thieme
→ Extraction group showed:
• Increased lateral translations during protrusion–retraction and speech.
• Longer condylar trajectories, more rotation.
• ≥ 25% of cases exhibited altered mandibular kinematics.
Authors conclude extractions modify mandibular motion and warrant TMJ functional evaluation before extraction decisions.
BIBLIO - PER - .FULLdocx
https://www.facebook.com/groups/orthodonticmalpracticevictims/posts/1643435563281642/
Effects of orthodontics on Temporomandibular Joints (TMJ)
1) Artun J., Hollender L.G., Truelove E.L.
Relationship between orthodontic treatment, condylar position, and internal derangement in the temporomandibular joint. Am J Orthod Dentofacial Orthop. 1992;101(1):48–53. https://pubmed.ncbi.nlm.nih.gov/1731488/
→ Tested whether incisor retraction affects condylar position. Post-treatment tomograms showed posteriorly displaced condyles in extraction cases and a higher frequency of TMJ clicking, suggesting posterior repositioning can contribute to joint strain in some patients.
2) Londoño A., Assis M., Fornai C., Greven M.
Premolar Extraction Affects Mandibular Kinematics. Eur J Dent. 2023;17(3):756–764.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10569881/
→ Extraction group showed:
• Increased lateral translations during protrusion-retraction and speech.
• Longer condylar trajectories, more rotation.
• ≥ 25 % of cases exhibited altered mandibular kinematics.
• Authors conclude extractions modify mandibular motion which may be a cause of TMD, and hence a reason to avoid premolar extractions.
3) Okeson J.P., de Leeuw R.
Differential diagnosis of temporomandibular disorders and occlusal correlates. Dent Clin North Am. 1995;39(2):261–285.
https://pubmed.ncbi.nlm.nih.gov/7781299/
→ Notes that loss of posterior support or altered guidance increases TMJ loading; recommends screening before retraction or extraction mechanics. Highlights that occlusal factors—especially loss of posterior support or altered anterior guidance—can increase joint loading and predispose to pain or internal derangement in susceptible patients. The authors emphasize pre-orthodontic screening of joint health prior to major occlusal changes such as retraction or extractions.
4) Wyatt W.E.
Preventing adverse effects on the temporomandibular joint during orthodontic treatment. Am J Orthod Dentofacial Orthop. 1987;91(6):493–499.
https://pubmed.ncbi.nlm.nih.gov/3473929/
→ Warns that over-retraction and loss of posterior support can destabilize the TMJ; advocates force control and condylar monitoring.
https://www.facebook.com/groups/orthodonticmalpracticevictims/posts/1613163362975529/
1) Shen Y.W., Hsu J.T., Wang Y.H., Huang H.L., Fuh L.J., Shen Y.W. Evaluation of alveolar bone thickness following orthodontic extraction treatment: A CBCT study. J Dent Sci. 2014;9(3):282–288. ScienceDirect
→ CBCT demonstrated significant alveolar bone loss on the labial side of maxillary incisors after extraction therapy. Retraction led to thinning of the alveolar housing.
1) Jiang J., Hu W., Zhang Y., Chen J. Alveolar bone changes following orthodontic treatment with premolar extractions: A systematic review and meta-analysis. Sci Rep. 2018;8:17036. PubMed | PMC
→ Meta-analysis confirmed alveolar bone loss and dehiscence are more prevalent in extraction cases. Incisor retraction compromises alveolar bone support.
1) Sadek M.M., Sabet N.E., Hassan I.T. Three-dimensional assessment of alveolar bone changes after orthodontic treatment with and without premolar extractions. Am J Orthod Dentofacial Orthop. 2015;148(4):702–710. PubMed
→ 3D imaging shows marked reduction in alveolar bone thickness and height in extraction patients compared to non-extraction controls.
1) Lin L., Ahn H.W., Kim S.H., Chung K.R., Kim K.B., Nelson G. Tooth-bone discrepancy and alveolar bone loss in extraction vs. non-extraction orthodontic therapy: CBCT findings. Angle Orthod. 2014;84(3):400–406. PubMed
→ CBCT analysis: retraction of incisors in extraction cases caused alveolar bone dehiscence and fenestration. Non-extraction cases showed far less alveolar compromise.
1) Ahn H.W., Moon S.C., Baek S.H. Morphometric evaluation of alveolar bone following premolar extraction with maximum retraction. Korean J Orthod. 2013;43(5):272–279. PubMed | PMC
→ Maximum retraction after extraction increases risk of alveolar bone defects and resorption.
SYNTHESIS (FULLER VERSION):
Across CBCT studies, morphometric analyses, and systematic reviews, premolar extraction therapy with incisor retraction is strongly and consistently associated with alveolar bone compromise. The most common findings are:
Labial bone loss and thinning of the alveolar housing around maxillary incisors.
Dehiscence and fenestrations occur more frequently in extraction cases than in non-extraction controls.
Vertical height reduction of alveolar bone is seen after space closure.
Greater incisor retraction = greater risk of alveolar defects, resorption, and compromised periodontal support.
Non-extraction patients tend to maintain or even thicken alveolar bone, while extraction patients demonstrate marked thinning.
Systematic review/meta-analysis (Jiang 2018) confirms that alveolar bone loss is not incidental but a reproducible outcome of extraction-based orthodontics.
Overall, the evidence converges: extractions place incisors outside their natural bony envelope, leading to long-term structural vulnerability of the alveolus.
1) Albertini P., Barbara L., Albertini E., Willeit P., Lombardo L.
Soft-tissue profile changes in adult patients treated with premolar extractions. Am J Orthod Dentofacial Orthop.2024;166(2):171–178.
DOI | PubMed
→ 75 adults: mean lip retraction = 1.4 mm (upper) / 1.7 mm (lower). Thin lips retracted more, producing flatter profiles.
2) Bravo L.A.
Soft tissue facial profile changes after orthodontic treatment with four premolars extracted. Angle Orthod. 1994;64(1):31–42.
DOI | PubMed
→ 16 extraction cases: lips retracted ≈ 3.4 mm (upper) / 3.8 mm (lower) relative to E-line. Naso-labial angle ↑ by ~3.7°. Clear profile flattening.
3)Caplan D.
Soft-tissue changes following orthodontic treatment with premolar extractions. Angle Orthod. 1969;39(4):285–297.
DOI
→ One of the earliest systematic reports: found flattening of upper and lower lips after premolar extractions, with esthetic concerns raised.
4) Change of Lip Curvature Through Extraction and Non-extraction.
Kim B. et al. Appl Sci. 2024;14(24):11715.
Full text
→ Cephalometric study on 62 Class I cases; lip flattening was not always significant even with extraction, though incisor inclination influenced curvature.
5) Drobocky O.B., Smith R.J.
Changes in facial profile during orthodontic treatment with premolar extractions: long-term evaluation. Am J Orthod Dentofacial Orthop. 1989;95(3):220–230.
DOI | PubMed
→ Long-term follow-up: extraction patients had persistent lip retrusion and flattened profiles even years after retention.
6) Ekstam M., Gerstorf K., et al.
Effects of premolar extraction and orthodontic treatment in soft tissue and dental parameters. Acta Odontol Scand. 2023.
Full text
→ In extraction cases, soft tissue profile shows measurable lip retrusion, but variability depends on lip thickness and anchorage.
7) Kocadereli I.
Changes in soft tissue profile after orthodontic treatment with and without extraction. Am J Orthod Dentofacial Orthop.2002;122(1):67–72.
DOI | PubMed
→ Class I patients: extraction group showed more retracted lips and flatter profiles than non-extraction controls.
8) Kochar G.D.
Treatment effects and lip profile changes following extraction. J Orthod Res. 2023;11(2).
PMC
→ RCT in Class II patients: extraction groups showed greater lip retrusion and profile flattening than non-extraction.
9) Janson G., Valarelli F.P., et al. Relationship between maxillary incisor retraction and soft tissue changes. Am J Orthod Dentofacial Orthop. 2007;132(3):281–289. PubMed
→ Large sample confirmed extraction cases show significantly more lip retrusion compared with non-extraction.
10) Lew K.K.
Profile changes following orthodontic treatment of bimaxillary protrusion in adults. Eur J Orthod. 1989;11(4):375–381.
DOI | PubMed
→ Adults with bimax protrusion: 4 premolar extractions + incisor retraction ≈ 5.6 mm (upper) / 4.4 mm (lower). Naso-labial angle increased.
11) Looi L.K., Mills J.R. The effect of orthodontic treatment on the soft-tissue profile. Eur J Orthod. 1986;8(4):255–262. PubMed
→ Premolar extractions led to flattening of the soft-tissue profile compared to non-extraction controls. Changes persisted long-term.
12) Liao Y.F., Huang C.S., Lin J.N. Lip response to maxillary incisor retraction in bimaxillary protrusion patients. Am J Orthod Dentofacial Orthop. 2000;118(2):162–169. PubMed
→ Quantified ratio: ~1 mm of incisor retraction produced ~0.6 mm of upper lip retraction. Extraction therapy thus directly linked to lip
13) Pendse T.A., et al.
Effect of premolar extraction on lip strain and lip length. J Orthod Res. 2025;13(2).
Full text
→ Compared lip strain, thickness, lip fall in patients with incisor retraction + extraction. Found lip fall and strain varied by tissue thickness.
14) Qiao Q., Zhang L., Xie X., Bai Y., Su L.
Structured-light 3D assessment of soft-tissue changes after four-premolar extraction in young adult females. Am J Orthod Dentofacial Orthop. 2024;165(1):80–92.e4.
DOI | PubMed
→ 3D scans: posterior displacement of the upper lip ≈ –1.89 mm vs. controls. Clear flattening.
15) Rains M.D., Nanda R.
Soft-tissue changes associated with maxillary incisor retraction. Am J Orthod. 1982;81(6):481–488.
PubMed
→ Incisor retraction (with extractions) caused upper lip retrusion and reduced vermilion display. Authors emphasized that soft tissue changes were clinically visible and often esthetically undesirable flattening.
16) Riedel R.A.
An analysis of dentofacial relationships. Am J Orthod. 1950;36(4):297–321.
DOI
→ Early foundational cephalometric study. Riedel showed that extraction/retraction flattens lips, warning that excessive retraction may harm esthetics.
17) Sadry S., et al.
Analyzing the effects of tooth extraction on the lip in orthodontic treatment. Orthod Craniofac Res. 2022.
ScienceDirect
→ Extraction cases had reduced vermilion thickness and lip curvature changes, though not always esthetically negative if carefully planned.
18) Sadry S., et al.
Nasal profile changes after orthodontic tooth extraction. Orthod Craniofac Res. 2024.
ScienceDirect
→ Upper-premolar extractions sometimes gave upper lip protraction, while four-premolar extraction caused lower lip retraction; effect varies by extraction pattern.
19) Shen L.H., Xie T.Y., Jiang R.P., et al.
3D changes in lip vermilion after orthodontic extraction in adult females. Head Face Med. 2021;17(1):9.
DOI | PubMed
→ Vermilion surface area reduced by –51 to –70 mm². Clear lip thinning after extraction.
20) Talass M.F., Talass L., Baker R.C.
Soft-tissue profile changes resulting from retraction of maxillary incisors. Am J Orthod Dentofacial Orthop.1987;91(5):385–394.
DOI | PubMed
→ Classic ceph study: incisor retraction increased naso-labial angle.
→ Documented significant lip retraction and flattening after four-premolar extractions. The upper and lower lips retruded in proportion to incisor retraction, altering esthetics.
21) Wholley C.J., et al.
The Effects of Commonly Prescribed Premolar Extraction on Lip Profile. Angle Orthod. 2003;73(4):386–392.
Full text
→ Dental changes (incisor retraction, interincisal angle) correlate strongly with lip profile flattening in extraction protocols.
Synthesis
From Riedel (1950) and Caplan (1969) to modern 3D imaging (Qiao 2024, Pendse 2025), the literature consistently shows that premolar extraction + incisor retraction leads to lip retraction, reduced vermilion, and profile flattening.
Early pioneers (Riedel, Caplan) warned of esthetic risks.
Long-term studies (Drobocky & Smith 1989) confirmed flattening persists.
Recent 3D volumetric research (Shen, Qiao, Albertini) quantifies lip thinning and volume loss.
https://www.facebook.com/groups/1270654792948954/?multi_permalinks=25499855589602203&hoisted_section_header_type=recently_seen
A summary of premolar extraction risks
1) Potential impacts of premolar extractions
Premolar extractions/retractions predictably narrow the dental arches (in length and width) and thus the oral cavity/palate, with a risk of reducing tongue space. This shrinkage of the oral cavity space can lead to swallowing disorders, speech defects, chewing difficulties, tongue discomfort, as well as airway narrowing and breathing disorders.
The literature describes a link between extractions and pharyngeal narrowing/backward displacement of the hyoid bone, factors associated with sleep-disordered breathing (apnea, mouth breathing, snoring).
Airway narrowing can also promote forward head posture, changes in cervical spine curvature, and other postural disorders.
These mechanisms may contribute to systemic symptoms: general fatigue, reduced sports endurance, decreased vocal resonance, eating discomfort, chronic cervico-scapular pain, tachycardia, nervous-system disorders (chronic activation of the “fight-or-flight” mode), immune disorders, hair loss, and other comorbidities, and an overall decrease in quality of life.
The above systemic issues are general summaries from the stats of the survey that has reached 3400 people.
2) Orthodontic camouflage vs skeletal correction
Using extractions to camouflage a skeletal discrepancy (e.g., retruded mandible, narrow palate) does not treat the cause and may worsen initial symptoms. It can also complicate later surgery if such a procedure becomes necessary after the extraction/retraction phase.
The practitioner must:
inform the patient about the potential consequences of extractions (arch narrowing; impact on the tongue/airway/aesthetics) as well as available alternatives.
Put health objectives on the same level as occlusion/aesthetics.
Compare the “extractions/camouflage” option with expansion scenarios and/or skeletal correction/surgery.
Weigh benefits/risks for tongue space, airways, and postural stability.
3) Recommended clinical and paraclinical evaluation (before any extraction decision)
Pre-tx exams:
Airway: dedicated imaging (CBCT/volumetric assessments), nasal endoscopy if indicated
TMJ: clinical exam (masticatory/cervical muscles), imaging if necessary.
Functions: breathing. swallowing, chewing, speech; spinal posture
Myofunctional evaluation of tongue function
4) Current professional trends and caution
The use of premolar extractions has clearly decreased compared with past decades, in Europe and in the U.S., mainly due to aesthetic risks (flattened profile) and also—though to a lesser extent—due to respiratory risks.
However, the profession is not evolving fast enough.
The premolar-extraction rate in 2025 remains far too high.
The global average is estimated at about 50% of all patients undergoing orthodontic treatment. The decision to extract depends on the orthodontist's individual whim> there is no standard protocol for this standard of care.
So for now it is luck of the draw if a patient is extracted "prudently" by a risk-aware orthodontist or by someone who extracts in half their patients as a matter of course.
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https://www.facebook.com/groups/1270654792948954/?multi_permalinks=25509067872014308&hoisted_section_header_type=recently_seen
We often imagine the body as a collection of parts: the jaw, the spine, the hips, the feet. But anatomically and neurologically, these parts belong to a single kinetic chain. A change in one link inevitably affects the others. Understanding these connections reshapes how we see posture, balance, and even breathing.
1. THE BODY AS A CHAIN OF MOVEMENT
When we move, force and motion travel through the body along what researchers call kinematic chains — a term describing how bones and muscles transmit movement from one joint to another. The body’s design ensures stability and fluidity: each motion of the limbs requires a coordinated counter-motion elsewhere to maintain balance.
In human gait, for example, when the right leg moves forward, the right arm naturally swings backward. This is not a random reflex — it is a built-in neurological and mechanical strategy for maintaining equilibrium. The phenomenon, long observed in biomechanics, is orchestrated by central pattern generators (CPGs) in the spinal cord — neural circuits that synchronize the rhythm of arm and leg movements (Nature 2024). This cross-patterned rhythm stabilizes the trunk and conserves energy as we walk.
Yet the choreography extends beyond arms and legs. Subtle rotations of the pelvis, spine, shoulders, and headaccompany each stride, keeping our eyes level and our balance intact. These coordinated counter-rotations form what yoga, osteopathy, and martial traditions have long recognized: movement is not isolated but whole-body intelligence.
2. THE MANDIBLE’S HIDDEN ROLE
Although the jaw’s main task is chewing and speech, it is structurally anchored into the cranium and cervical spine, which means that any change in head or neck position influences the mandible — and vice versa.
The temporomandibular joint (TMJ) connects the jaw to the skull and is supported by powerful muscles — the masseter, temporalis, pterygoids, and the suprahyoid and infrahyoid groups. These muscles blend seamlessly into the neck’s deep stabilizers, such as the sternocleidomastoid and trapezius. When the mandible shifts laterally or opens, it subtly recruits and rebalances these cervical muscles, leading to micro-adjustments in the thorax and shoulder girdle.
This linkage has been documented in studies showing coordinated motion between jaw, head, and neck. One classic experiment on integrated jaw and neck function found that opening or moving the jaw invariably involves synchronized head–neck adjustments (ResearchGate). The authors described the body as a “kinematically linked” system — where the jaw never acts alone.
3. JAW MOTION DURING WALKING
Surprisingly, even walking involves the mandible.
A study titled Control of Human Mandibular Posture During Locomotion measured micro-movements of the jaw while subjects walked and hopped. Each heel strike produced a slight downward movement of the mandible — a reflex response that helps stabilize the head and dissipate vibration. During normal gait, these displacements were tiny but rhythmic, synchronized with each step (PubMed).
Osteopaths and posturologists have long observed this phenomenon qualitatively: as we walk, the jaw swings gently left and right, mirroring the body’s alternating load between legs. This is not a defect or compensation but part of the body’s finely tuned equilibrium. The mandible thus participates in the same oscillatory rhythm as the pelvis and shoulders, ensuring that sensory inputs — visual, vestibular, and proprioceptive — remain harmonized.
4. PELVIS, SHOULDERS, AND MANDIBLE: A RHYTHMIC DIALOGUE
During each gait cycle:
The right leg advances; the right hip moves forward.
Simultaneously, the right shoulder retracts, counter-balancing the trunk’s rotation.
The spine twists slightly, maintaining the head’s forward orientation.
The neck executes a fine counter-rotation to keep the gaze stable.
The mandible follows suit with micro-oscillations that mirror this rhythm.
This is an engineered dance of stability: every movement above the pelvis compensates and balances for those below. It’s why a misalignment in the foot, knee, or hip can propagate upward, eventually disturbing the head’s balance or the jaw’s resting position.
Conversely, a shift in the jaw or cranial base can ripple downward, influencing pelvic orientation and gait.
Osteopathic and postural medicine recognize these chains. Posturologists describe the stomatognathic system (the functional unit of teeth, jaws, and associated muscles) as a critical component of the body’s postural control network (PMC Review). Disturbances in bite or jaw alignment can alter head posture, which in turn shifts the body’s center of gravity and muscular tone along the spine, pelvis, and lower limbs.
5. A UNIFIED ENGINEERING
Seen through this lens, human movement resembles a well-tuned mechanical orchestra more than a set of disconnected levers. The gait cycle, breathing rhythm, and mandibular balance are all synchronized by the nervous system’s pursuit of equilibrium and efficiency.
When these relationships are disrupted — through injury, poor posture, dental malocclusion, or even stress — the resulting imbalance can cascade through the system, affecting areas seemingly far away from the source. This is why practices such as yoga, tai chi, and osteopathy emphasize global awareness: freedom in one joint depends on harmony in all the others.
In essence, the mandible does not just chew or speak; it participates in the living rhythm of the body. Each step, each breath, each subtle sway of the hips and shoulders is echoed — quietly — in the movement of the jaw.
(All links verified October 2025)
https://www.facebook.com/groups/extractionorthodonticsreversal/posts/25716594297928330/
1) Chewing performance in orthodontic patients treated with extraction of premolars. J Chosun Obr. 2019; 43(3):196–203.
https://www.chosunobr.org/journal/download_pdf.php?doi=10.21851%2Fobr.43.03.201909.196
→ Direct extraction study comparing pre- and post-treatment masticatory function. Patients with premolar extractions showed shorter, slower chewing cycles and reduced efficiency versus baseline. Indicates that orthodontic extractions impair chewing kinetics, especially with narrowed arch form.
2) English J.D., Buschang P.H., Throckmorton G.S.
Does malocclusion affect masticatory performance? Angle Orthod. 2002; 72(1):21–27.
https://pubmed.ncbi.nlm.nih.gov/11881753/
→ Established that malocclusions—including those created by retractive mechanics—significantly reduce chewing efficiency, yielding larger bolus particle size and decreased breakdown rate.
3) Fathalla R., Samih H.M., Ramadan A.A.
Assessment of occlusal forces in patients treated with four first-premolar extractions: An in vivo study using the T-Scan III system. Dent Stud. 2023; 5(1):70-76.
https://pubmed.ncbi.nlm.nih.gov/38034277/→ Ten adolescent patients treated with four-premolar extractions showed reduced anterior bite-force contribution and slight posterior redistribution. Overall occlusal force balance achieved, but anterior functional weakness persisted, suggesting compensatory rather than normal adaptation.
4) Haraldson T., Carlsson G.E., Ingervall B.
Functional state of the masticatory system in denture and natural dentition subjects. Acta Odontol Scand. 1979; 37(6):333–341.
https://pubmed.ncbi.nlm.nih.gov/294451/
→ Classic physiologic reference: demonstrated that reduced dental arches or missing teeth sharply decrease bite-force and chewing efficiency. Provides the foundational evidence that smaller dental arches—whether edentulous or extraction-induced—mean weaker mastication.
5) Helkimo E., Ingervall B., Carlsson G.E.
Bite force and functional state of the masticatory system in young adults. Swed Dent J. 1971; 64(3):153–160.
https://pubmed.ncbi.nlm.nih.gov/5285249/
→ Measured normal bite-force in young adults and correlated it with occlusal contact area. Found that bite-force decreases linearly with loss of posterior support—a principle directly relevant to orthodontic extractions.
6) Kohyama K., Mioche L., Martin J.F.
Chewing patterns of subjects with occlusal disharmonies. Arch Oral Biol. 2002; 47(6):461–471.
https://pubmed.ncbi.nlm.nih.gov/12000302/
→ Subjects with narrow arches and occlusal disharmonies (often post-extraction) exhibited longer, less efficient chewing cycles and maladaptive muscular coordination. Supports the link between arch constriction and functional decline.
7) Miura H., Araki Y., Morita M.
Relationship between occlusal contact area and bite-force in adults. J Oral Rehabil. 1981; 8(5):465–471.
https://pubmed.ncbi.nlm.nih.gov/6945325/
→ Quantified bite-force as a direct function of occlusal contact area. Showed that any reduction in arch width or tooth number lowers maximal bite-force, forming the physiologic basis for extraction-related weakness.
8) Peyron M.A., Lassauzay C., Woda A.
Effects of dental and prosthetic status on masticatory performance. J Dent Res. 2002; 81(8):545–549.
https://pubmed.ncbi.nlm.nih.gov/12215566/
→ Demonstrated that fewer functional teeth and reduced occlusal surface area yield lower masticatory output, confirming the mechanical cost of arch reduction.
9) Scientific Reports (Open Access).
Changes in occlusal function after extraction of premolars: A two-year follow-up study. Sci Rep. 2021; 11:8357216.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8357216/
→ Two-year follow-up of non-extraction vs. two- and four-premolar extraction groups. Occlusal contact area and bite-force fell sharply after treatment; only partial recovery at 24 months. Four-premolar group never regained baseline force, confirming persistent mechanical deficit.
10) Shinogaya T., Adachi A., Watanabe M.
Effects of occlusal condition on masticatory efficiency. J Oral Rehabil. 1999; 26(9):739–745.
https://pubmed.ncbi.nlm.nih.gov/10511269/
→ Showed that reducing the number of active occlusal contacts markedly impairs masticatory efficiency. The findings parallel post-extraction occlusal conditions and validate their functional impact.
SYNTHESIS
· Premolar extractions reduce occlusal contact area, arch width, and anterior bite-force, resulting in slower, less efficient chewing and maladaptive muscle patterns.
· Foundational bite-force studies (Helkimo 1971; Haraldson 1979; Miura 1981) established that any loss of dental units or arch constriction directly weakens masticatory power.
· Modern clinical studies confirm extraction patients experience longer chewing cycles, smaller bolus breakdown, and incomplete recovery of occlusal function over time.
· Functional adaptations may partially compensate but at the expense of efficiency and possibly joint over-use.
PUBMED.NCBI.NLM.NIH.GOV
Results of biomonitoring analyses in Biomonitoring Laboratory, Helsinki, Finland in 1997 - PubMed
In 1997 a total of 4848 results of 47 different analytes from blood or urine specimens, were performed in the Finnish Institute of Occupational Health, Biomonitoring Laboratory, Helsinki, Finland. The results of these service analyses were registered in a database with additional information concern...
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Effects of Premolar Extractions on Alveolar Bone (Remodeling and Loss)
1) Sarikaya S., Haydar B., Ciger S., Ariyurek M.
Changes in alveolar bone thickness due to retraction of anterior teeth.
Am J Orthod Dentofac Orthop. 2002;122(1):15–26.
[DOI] [PubMed] [Google Scholar]
→ Demonstrated thinning of the labial cortical plate (~1–2 mm) following anterior tooth retraction; risk of dehiscence in thin alveolar biotypes.
2) Lund H., Grondahl K., Grondahl H.G.
Cone beam computed tomography evaluations of marginal alveolar bone before and after orthodontic treatment combined with premolar extractions.
Eur J Oral Sci. 2012;120(3):201–211.
[DOI] [PubMed] [Google Scholar]
→ CBCT analysis revealed measurable loss of marginal alveolar bone height and thickness on both labial and lingual aspects after extraction space closure.
3) Sun Q., Lu W., Zhang Y., Peng L., Chen S., Han B.
Morphological changes of the anterior alveolar bone due to retraction of anterior teeth: a retrospective study.
Head Face Med. 2021;17(1):30.
[DOI] [PMC:8284009]
→ Quantified anterior plate thinning of ~1.0–1.5 mm depending on retraction magnitude; stresses importance of torque control.
4) Hassan S., Shaikh A., Fida M.
Effect of incisor inclination changes on Cephalometric points A and B.
J Ayub Med Coll Abbottabad. 2015;27(2):268–273.
[PubMed] [Google Scholar]
→ Cephalometric correlation between incisor retraction, alveolar housing change, and sagittal displacement of points A and B.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8284009/?fbclid=IwY2xjawNrRANleHRuA2FlbQIxMABicmlkETF6SzZlT3ZiNkFmb3BaTk92AR4zQDDuKCWE2bDpi54aa4JY3cTV9kpI0Wi56xx3TfR87ECCol_CKXNPFmhS3g_aem_vBBPvLiLpOUuZWTvLd3tmg
Sun Q, Lu W, Zhang Y, Peng L, Chen S, Han B. Morphological changes of the anterior alveolar bone due to retraction of anterior teeth: a retrospective study. Head Face Med. 2021 Jul 16;17(1):30. doi: 10.1186/s13005-021-00277-z. PMID: 34271939; PMCID: PMC8284009.
Synthesis:
Evidence from cephalometric and CBCT studies shows that premolar extractions with anterior retraction—and, in non-extraction contexts, large faciolingual movements without adequate torque control—affect the anterior alveolar housing. Retraction and root proximity to cortical plates are associated with thinning of the labial (and/or palatal) cortical plate, and in thin biotypes, with dehiscence/fenestrations. Quantitatively, Sarikaya et al. (2002) reported labial plate decreases of approximately 1–2 mm after incisor retraction; Lund et al. (2012) showed measurable marginal alveolar bone loss on both labial and lingual sides after extraction space closure on CBCT; and Sun et al. (2021) found anterior plate thinning of roughly 1.0–1.5 mm depending on the degree of retraction. Overall, alveolar remodeling appears unfavorable when movements push roots against cortical boundaries.
https://www.facebook.com/groups/extractionorthodonticsreversal/posts/25746248661629560/
https://academic.oup.com/ejo/article-abstract/27/6/585/400867
A comparative study of dental arch widths: extraction and non-extraction treatment.
Fulya Işık, Korkmaz Sayınsu, Didem Nalbantgil, Tülin Arun
European Journal of Orthodontics, Volume 27, Issue 6, December 2005, Pages 585–589, https://doi.org/10.1093/ejo/cji057
Published: 28 October 2005
https://pmc.ncbi.nlm.nih.gov/articles/PMC10943680/
J Clin Exp Dent. 2024 Feb 1;16(2):e137–e144. doi: 10.4317/jced.61064
Effect of orthodontic premolar extraction on maxillary teeth angulation and arch dimensions in adolescent patients: A 3-D digital model analysis
Ahmed Abohabib 1,✉, Maria J Viñas 2, Josep M Ustrell 3 PMCID: PMC10943680 PMID: 38496807
Dental arches shrink after premolar extractions, both in width and in length.
In adolescents, not only do dental arches shrink they grow less, due to the loss of alveolar bone and the retraction, than in non-extracted adolescents:
Growth in adolescents age 12-14 with palate expansion and no extractions: 4 mm wider arches.
Growth in adolescents 12-14 with no extractions. 2.5mm wider arches.
Growth in adolescents 12-14 with premolar extractions. Negative ,8 mm. They grow "less" at a time when every bone in their body is growing more.
(Note that some articles report that the width between canines INCREASE after premolar extractions. This is true. But do not get your hopes out. One of the studies has the integrity to mention that this is NOT real increase. The canine has been pushed back to the missing premolar space, where it has a wider area. The actual inter-canine space--where the canine once was--has shrunk.
https://www.facebook.com/groups/1270654792948954/?multi_permalinks=25783237691263990&hoisted_section_header_type=recently_seen
Fascinating recent study on how the nose, lip, and philtrum change with premolar extraction.. The nose gets longer, and the philtrum/lip get flatter, with the nasolingual angle steepening about 6.6 degrees. The charts are really detailed. It is controversial that they conclude that the potential adverse profile changes with premolar extractions in ADULTS is more significant than in children--and that the nose changes is a risk that orthodontists should take into cosideration..
Sadry et al., 2024 — “Nasal profile changes after orthodontic tooth extraction in adults”
Non-extraction cases showed a decrease in NLA, while extraction cases showed an increase in NLA.
Full text/abstract: https://www.sciencedirect.com/science/article/pii/S2468785523003683
Note that the public may have the misconception that the "lips" is that red thing (lip vermillion) we commonly call lips. The upper lip is defined anatomically as the muscle that includes the entire area from the base of the nose to the end of the vermillion aka philtrum. . It is not just the "red part" that flattens with upper premolar extractions, it is the philtrum.
Here is AI's explanation of lips:
Key anatomical details:
- The upper lip includes (in its midline) the groove called the Philtrum, which extends from the subnasale (base of the nose) to the upper vermilion border. elementsofmorphology.nih.gov+1
- The surface of the lip region comprises (from outside inward): normal facial skin at its superior or lateral boundary, the vermilion border and vermilion zone (the reddish portion) and then the oral mucosa on the inside. elementsofmorphology.nih.gov+1
- The lips serve many functions: speech articulation (labial, bilabial sounds), food intake (sealing, sucking), facial expression (smile, pucker) and tactile/erogenous sensation. Wikipedia
Therefore in the context of soft-tissue profile changes, when you refer to “the lip” you are referring to the upper border of the oral aperture, including the vermilion zone of the upper lip and the groove above (the philtrum) leading to the base of the nose.
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Do orthodontists when they explain the phenomenon of predictable lip flattening with extractions explain how the lip is defined, or are patients led to understand that only the lip vermillion (red part) is affected (hence a minor change)? How about the changes to the nose?
Effects of Premolar Extractions or Agenesis on Jaw/Facial Growth in Growing Patients
Bertl M.H., Bertl K., Wagner M., et al. Second premolar agenesis is associated with mandibular form: a geometric morphometric analysis. Int J Oral Sci. 2016;8(4):254–260. PubMed | Full text (https://www.nature.com/articles/ijos201623) → CBCT / morphometric: mandibular cross-sections are narrower/smaller in second-premolar agenesis. Reduced alveolar support limits basal mandibular development.
Brézulier D., Raimbault P., Jeanne S., Davit-Béal T., Cathelineau G. Association between dental agenesis and facial morphology: cross-sectional study in France. PLoS One. 2024;19(12):e0314404. PubMed | Full text → Agenesis correlated with maxillary constriction, greater lower facial divergence, and reduced chin projection.
Brodie A.G. On the Growth of the Jaws and the Eruption of the Teeth. Angle Orthod. 1942;12(1):25–40. DOI → Provided growth curves that became the benchmark for later extraction caution. Showed forward mandibular growth potential, which premolar extractions can compromise.
De Castro N. Second-premolar extraction in clinical practice. Am J Orthod. 1974;65(2):115–143. PubMed → Clinical guidance piece, discusses timing of second-premolar extraction relative to growth. Notes that removing teeth during active growth may alter eruption patterns and basal bone development.
Dellavia C., Catti F., Sforza C., et al. Craniofacial growth in ectodermal dysplasia: an eight-year longitudinal study. Head Face Med. 2010;6:18. PubMed | Full text → Longitudinal agenesis cohort: showed alveolar bone deficiency and midfacial undergrowth.
Dewel B.F. Serial extraction in orthodontics: Indications, objectives, and treatment procedures. Am J Orthod. 1954;40(11):906–926. DOI → Introduced serial extraction as systematic protocol—later criticized for blocking forward mandibular growth.
Dewel B.F. Serial extraction: its limitations and contraindications in orthodontic treatment. Am J Orthod. 1967;53(12):904–921. DOI → Warned explicitly: backward mandibular rotation and flattened profiles from extractions during growth.
Dupré N., Rallo A., et al. Reduced bone dimension in oligodontia patients: maxillary and mandibular CBCT study. Orthod Craniofac Res. 2023;26(4). DOI → Agenesis cases had narrower alveolar dimensions even at dentate sites, confirming jaw development restriction.
Graber T.M. Serial extraction: a continuous diagnostic and decisional process. Am J Orthod. 1971;60(6):541–575. PubMed → Warned that extractions must be growth-sensitive; otherwise they impede jaw development.
Hotz R.P. Guidance of eruption versus serial extraction. Trans Eur Orthod Soc. 1970;46:311–335. PubMed → Advocated eruption guidance; noted that extraction may cause narrow arches and growth restriction.
Jurek A., Antoszewska-Smith J., Turp I., et al. Effect of tooth agenesis on mandibular morphology and position: 3D cephalometric study. Int J Environ Res Public Health. 2021;18(22):11876. PubMed | Full text → Agenesis patients had shorter mandibles and narrower symphyses, consistent with growth restriction.
Kjellgren B. Serial extraction as a corrective procedure in dental orthopedic therapy. Am J Orthod. 1948;34(5):372–379. DOI → First formal proposal of serial extraction. Already noted risk of arch constriction and altered development.
Lloyd Z.B. Serial extraction as a treatment procedure. Angle Orthod. 1956;26(4):291–307. DOI → Protocol emphasizing evaluation of arch length vs. basal bone growth. Noted risk of jaw growth restriction if done prematurely.
Norman F. Serial Extraction. Angle Orthod. 1965;35(1):1–25. DOI → Mid-60s review: cautioned that premature extraction could limit basal bone growth.
Oeschger E.S., Eliades T., Papadopoulou A.K., Gkantidis N. Number of teeth is associated with facial size in humans. Sci Rep. 2020;10:58565. PubMed | Full text (https://www.nature.com/articles/s41598-020-65376-3) → Population study: fewer teeth directly linked to smaller faces.
Rachmiel A., Emodi O., et al. Management of severely atrophic maxilla in EEC syndrome. Case Rep Plast Surg Hand Surg. 2018;5(1). PubMed | Full text → Syndromic agenesis → atrophic maxillae, underscoring the role of teeth in maintaining alveolar/jaw development.
Richardson A. A review of changes in lower arch length. Br J Orthod. 1979;6(3):151–154. PubMed → Arch length naturally declines with age; extractions accelerate the reduction, constraining mandibular development.
Ringenberg Q.M. Serial extraction: Stop, look, and be certain. Am J Orthod. 1964;50(5):328–336. DOI → Controlled St. Louis study (1954–1959): delayed forward mandibular growth, flatter/concave profiles with incisor retraction. Famous line: “After using forceps, there is no turning back.”
Ringenberg Q.M. Influence of serial extraction on growth and development of the maxilla and mandible. Am J Orthod. 1967;53(2):89–102. DOI → Directly measured restricted maxillary/mandibular growth after serial extractions.
Schieffer L., Nowak R., May A., et al. Curve of Spee and second mandibular premolar agenesis—mandibular morphology differences. Appl Sci. 2022;12(22):11747. Full text → Agenesis linked to smaller mandibles and altered morphology; mechanism: alveolar bone deficiency.
Tweed C.H. Indications for the extraction of teeth in orthodontic procedure. Am J Orthod Oral Surg. 1944;30(8):405–428. DOI → Landmark paper advocating extractions to reduce protrusion—later criticized for producing flat profiles and altering jaw growth direction.
Zierhut E.C., Joondeph D.R., Artun J., Little R.M. Long-term profile changes associated with premolar extractions. Am J Orthod Dentofacial Orthop. 2000;118(2):91–103. PubMed → Long-term follow-up: extraction patients show restrained jaw projection and flatter profiles vs. non-extraction.
Synthesis
Agenesis and extractions operate by the same mechanism: fewer teeth → less alveolar bone → restricted jaw growth → flatter profiles. Historic warnings (Brodie 1942; Tweed 1944; Dewel 1954, 1967; Ringenberg 1964, 1967; Graber 1971; Hotz 1970) anticipated what modern CBCT/morphometric studies (Bertl 2016; Jurek 2021; Schieffer 2022; Brézulier 2024) have quantified.