The effect of vertical growth pattern on mandibular incisor proclination in non-extraction Invisalign Teen® cases.

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Hennessey, Declan
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Objectives: To investigate the effect of vertical growth pattern on the position of the mandibular incisors for non-extraction Invisalign teen® patients, with or without interproximal reduction. Subjects and methods: A retrospective chart review consisting of 40 (26 girls;14 boys) Caucasian adoloscent patients in the permanent dentition (12- 18) was undertaken. Subjects were categorized into 4 groups based on the value of the pre-treatment lower dentition crowding and value of patients mandibular plane angle (MPA). Crowding was assessed as mild (0-3.9mm) or moderate (4-5.9mm) and MPA as normal growth (30-37°) or vertical growth (>37°). The sample provided 10 normal growth/mild crowding, 10 vertical growth/mild crowding, 10 normal growth/moderate crowding and 10 vertical growth/moderate crowding subjects. Measurements were taken from digitized cephalograms to determine the changes in the lower incisors from T0 (pre-treatment) to T1 (post-treatment). Interproximal reduction (IPR) and buccal expansion were recorded as contributing parameters to crowding resolution. Statistical analysis included a paired t-test and ANOVA. Changes in parameters and the final lower incisor position were evaluated. Results: No significant increase in buccal expansion between the 4 groups (p<0.05) was observed. IPR average values for the Normal and Vertical growth/ mild crowding groups were
Invisalign vertical growth pattern lower incisor proclination