Spee curve, кривая Шпее
Jun. 10th, 2025 06:55 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
healthy_back Ещё одна шарлатанская выходка. Я видел исследование, но к сожалению, ссылки не сохранил. Там было прямым текстом написано, что никаких иследований, подтверждающих какую-то пользу от её выравнивания - нет. То исследование найти не могу, но оставляю ссылки на то, что есть
https://pmc.ncbi.nlm.nih.gov/articles/PMC10901573/
Conclusion
Bite force variations across various CS types were linked to gender and habits. Chewing ability showed no differences concerning gender, habits, TMJ problems, caries, or restorations, emphasizing CS's significant impact on bite force while showcasing the unchanged nature of chewing ability amidst diverse factors.
https://www.worldwidejournals.com/indian-journal-of-applied-research-(IJAR)/recent_issues_pdf/2014/November/November_2014_1492773313__44.pdf
https://www.researchgate.net/publication/365057463_A_Virtual_Investigation_of_the_Change_in_Arch_Length_from_Leveling_a_Curve_of_Spee_A_Pilot_Study
https://www.ajodo.org/article/S0889-5406(20)30834-9/fulltext
https://www.preprints.org/manuscript/202306.2259/v1
Functional Significance of the Curve of Spee: Electro-myographic Analysis of Young Adults-A Preliminary Study
3. Results
This study evaluated the influence of the arrangement of dental elements in sagittal view on the contractile activity of the masticatory muscles.
The subjects examined presented curves of Spee with mild depth, zero depth and in some cases had a negative curve (inverted concavity), probably caused by previous orthodontic treatment. The study shows that in the arches where the curve of Spee is more flattened and levelled, the maximum depths of the curve are often reached at the level of the distal buccal cusp of the first molar.
A further observation made concerns the differences in the depth of the curves in the two hemiarches, left and right, in the same subject.
It was noted that the curvatures of the two hemiarches are different, in a variably marked manner, and that the hemiarches in which the third molar is present are those with greater curvature. In fact, the presence of third molars in the arch causes a significant increase in the curve of Spee. The results show that the hemiarch in which the curvature is deepest is the hemiarch of the subject in which the occlusal contacts in maximum intercuspation are greater (as observed by colorimetric evaluations) and in which the stress resulting from occlusion in maximum intercuspation appears to be more distributed at the molar level and less localized at the premolar, canine and incisor levels. In contrast, in the arches or hemiarches in which the curve of Spee is flatter and almost level, stress appears to be more evenly distributed over both anterior, lateral and posterior elements.
With these curve depth values (reduced, zero, or reversed), an increased activity in the anterior temporalis was noted. The BAR index (occlusal centre of gravity) was found to vary in all subjects and be delocalized anteriorly in a variable manner in the 5 electromyographic recordings performed per participant. In addition to the BAR index, the electromyographic evaluations showed that IMPACT was another parameter which was often found to be lower than the normal value range. The system's fit bite algorithm indicated in these cases the need for shim additions in the posterior sectors (Figure 1). Changes in MVC activity recorded in muscle activity while seated and activity measured in orthostatism presented no significant differences; both the tracings and the indices were found to be similar, the slight differences presented being related to interpersonal variations. Visual inputs were found to be irrelevant in the muscle activity of the masticatory muscles examined. The slight differences in developed contractile activity (measured in microvolts, along the vertical y-axis of the ordinates of the electromyographic tracing) reoccurred and were reflected in slight, nonsignificant differences at the level of the indices evaluated.
https://pubmed.ncbi.nlm.nih.gov/34084757/
Results: Von mises over the mandible was higher in flat than in curve model. The highest stress levels were detected at the Mesio-buccal cusp tip of first molar for flat and curved simulation (5053, 3304) Mpa respectively. Mesio-distally, the teeth displacement was higher in curve model than in flat one. The maximum distal displacement, in flat model, was seen in central and lateral incisors. While, in curve model, the maximum distal displacement was grasped within first and second premolars.
Conclusions: Flatting the COS magnify the stresses over whole mandible and reduce lower teeth displacement mesio-distally. We speculated that the readjustment of the COS after orthodontic treatment could reduce the stress and displacements on the lower anterior teeth and decrease the lower anterior teeth crowding relapse.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10901573/
Conclusion
Bite force variations across various CS types were linked to gender and habits. Chewing ability showed no differences concerning gender, habits, TMJ problems, caries, or restorations, emphasizing CS's significant impact on bite force while showcasing the unchanged nature of chewing ability amidst diverse factors.
https://www.worldwidejournals.com/indian-journal-of-applied-research-(IJAR)/recent_issues_pdf/2014/November/November_2014_1492773313__44.pdf
https://www.researchgate.net/publication/365057463_A_Virtual_Investigation_of_the_Change_in_Arch_Length_from_Leveling_a_Curve_of_Spee_A_Pilot_Study
https://www.ajodo.org/article/S0889-5406(20)30834-9/fulltext
https://www.preprints.org/manuscript/202306.2259/v1
Functional Significance of the Curve of Spee: Electro-myographic Analysis of Young Adults-A Preliminary Study
3. Results
This study evaluated the influence of the arrangement of dental elements in sagittal view on the contractile activity of the masticatory muscles.
The subjects examined presented curves of Spee with mild depth, zero depth and in some cases had a negative curve (inverted concavity), probably caused by previous orthodontic treatment. The study shows that in the arches where the curve of Spee is more flattened and levelled, the maximum depths of the curve are often reached at the level of the distal buccal cusp of the first molar.
A further observation made concerns the differences in the depth of the curves in the two hemiarches, left and right, in the same subject.
It was noted that the curvatures of the two hemiarches are different, in a variably marked manner, and that the hemiarches in which the third molar is present are those with greater curvature. In fact, the presence of third molars in the arch causes a significant increase in the curve of Spee. The results show that the hemiarch in which the curvature is deepest is the hemiarch of the subject in which the occlusal contacts in maximum intercuspation are greater (as observed by colorimetric evaluations) and in which the stress resulting from occlusion in maximum intercuspation appears to be more distributed at the molar level and less localized at the premolar, canine and incisor levels. In contrast, in the arches or hemiarches in which the curve of Spee is flatter and almost level, stress appears to be more evenly distributed over both anterior, lateral and posterior elements.
With these curve depth values (reduced, zero, or reversed), an increased activity in the anterior temporalis was noted. The BAR index (occlusal centre of gravity) was found to vary in all subjects and be delocalized anteriorly in a variable manner in the 5 electromyographic recordings performed per participant. In addition to the BAR index, the electromyographic evaluations showed that IMPACT was another parameter which was often found to be lower than the normal value range. The system's fit bite algorithm indicated in these cases the need for shim additions in the posterior sectors (Figure 1). Changes in MVC activity recorded in muscle activity while seated and activity measured in orthostatism presented no significant differences; both the tracings and the indices were found to be similar, the slight differences presented being related to interpersonal variations. Visual inputs were found to be irrelevant in the muscle activity of the masticatory muscles examined. The slight differences in developed contractile activity (measured in microvolts, along the vertical y-axis of the ordinates of the electromyographic tracing) reoccurred and were reflected in slight, nonsignificant differences at the level of the indices evaluated.
https://pubmed.ncbi.nlm.nih.gov/34084757/
Results: Von mises over the mandible was higher in flat than in curve model. The highest stress levels were detected at the Mesio-buccal cusp tip of first molar for flat and curved simulation (5053, 3304) Mpa respectively. Mesio-distally, the teeth displacement was higher in curve model than in flat one. The maximum distal displacement, in flat model, was seen in central and lateral incisors. While, in curve model, the maximum distal displacement was grasped within first and second premolars.
Conclusions: Flatting the COS magnify the stresses over whole mandible and reduce lower teeth displacement mesio-distally. We speculated that the readjustment of the COS after orthodontic treatment could reduce the stress and displacements on the lower anterior teeth and decrease the lower anterior teeth crowding relapse.