Effects of retraction of anterior teeth and initial soft tissue variables on lip changes in Japanese adults

Abstract

Aim: To estimate the changes in the lip with the retraction of anterior teeth in orthodontically treated patients. Objective: To study the amount the amount of changes seen in the upper lip with the various degrees of retraction of the upper anterior teeth in patients under orthodontic correction. Background: In orthodontic treatment the correction of anterior teeth proclination is carried out by creating space with extractions. With the retraction of the proclined anterior teeth, the lip which is in close contact with it also undergoes changes based on the degree of retraction. This study aims to analyse the various changes of the lip with the changes in anterior teeth position. Materials and method: Pre-and post-treatment cephalogramsof 41 patients who have undergone correction of class I or class II division I malocclusion is collected and traced manually and analysed cephalometricallyfor this study. Result: Positive correlation between the retractions of the upper lip following the upper teeth retraction is seen in an average of 0.51 cases. Negative correlation i.e. increase in the lip thickness with the retraction of upper anterior teeth is seen in an average of 0.29 cases and no changes are seen after the anterior teeth retraction in average of 0.19 cases.

Unpredictability of soft tissue changes after camouflage treatment of Class II division 1 malocclusion with maximum anterior retraction using miniscrews

“…(Table 3). The increased thickness of the upper lip was consistent with the results of previous studies, 3,4,12 but the magnitude of change in the maximum group was relatively large. The reduction in lip strain may be a result of the recovery of upper lip thickness because of hard tissue retraction.…”

“…[2][3][4][8][9][10][11] In this study, we used maximum anchorage for treating Class II Division 1 malocclusion to examine how soft and hard tissues respond in cases with very large retractions of the anterior teeth. Soft and hard tissue responses were compared between the moderate and maximum retraction groups, with the hypothesis that soft and hard tissue responses differ when using maximum anchorage for retracting the anterior teeth maximally.…”

“…First, the ratio of the amount of soft tissue movement to the amount of tooth retraction can be affected by many factors, including dentofacial morphology, age, sex, ethnicity, and study methodology. 4,8,14 Moreover, owing to individual variability in soft tissues of the musculonervous system, it was difficult to determine the accuracy of lip posture during imaging. Although lip strain should be considered in both the soft tissue analysis and lip thickness evaluation, it does show not only differences between individuals, but also temporal differences within individuals; accordingly, these variables could not be controlled for or quantified.…”

“…1 Among the facial soft tissue changes resulting from orthodontic treatment, there is particular interest in changes in the position and contour of the lips, and various methods of predicting posttreatment soft tissue changes have been reported to establish a diagnosis and treatment plan. [2][3][4][5] Choi et al 2 reported that in adult female patients with Class II Division 1 malocclusion, the ratios of movement between labrale superioris (Ls) and labrale inferioris (Li) to the extent of anterior teeth retraction are 1:0.45 and 1:2.08, respectively, and that the amount of posterior movement of Ls is correlated with posterior movement of the maxillary incisal edge.…”

Avaliação das Alterações Verticais e Horizontais do Lábio Superior após Retração de Incisivos Superiores

“…No presente estudo, os lábios superiores exibiram alteração significante após a retração dos incisivos RESULTADOS DISCUSSÃO superiores, com uma taxa de 0,8 mm de reposicionamento posterior para cada milímetro de retração dos incisivos. Esta taxa de resposta labial foi maior do que as relatadas anteriormente, que variaram entre 0,25 e 0,65 mm 3,5,6,26,27 . Porém, a variabilidade em espessura, tonicidade e composição adiposa dos tecidos moles faciais diversifica a forma com que estes respondem às mudanças dento-esqueléticas 28,29 , sendo considerada imprevisível por alguns autores 7,30 .…”