Occlusal Plane Change as a Predictor for Class-II Molar Correction

Materials and Methods: The subjects for this retrospective study had participated in a prospective, longitudinal, randomized clinical trial designed to examine the effectiveness of early treatment with headgear/biteplane (H) or a bionator (B), compared to observation (O), among subjects with a Class II malocclusion. The occlusal plane changes were measured in relation to the SN plane. Dental casts were used to score molar and canine classification from 1 to 5 (1= full cusp class II to 5 = class I) which were then added together to get a total score (TS) (bilateral class I molar and canine TS = 20). Data were collected at the start of treatment (DC1), and at various time-points until the end of treatment (DCF). 211 subjects (69 B, 73 H, and 69 O) were used in the analysis..

Results: Change in TS from DC1 to DCF did not vary by treatment group (p=0.27, mean change B 6.41, H 6.42, O 5.33). Change in SN OP angle during the course of treatment was small and did not vary by treatment group (p=0.65, mean degree change B 1.77, H 1.30, O 1.70). The change in molar and canine classification TS was not correlated, r=0.00 (p=0.97), with the change in the SN-OP angle.

Conclusion: Changes in molar and canine classification over the course of treatment did not differ significantly for those with bionator or headgear early treatment or adolescent comprehensive treatment. Changes in SN-OP angle were small, did not vary by treatment group and were not correlated with the changes in molar and canine classification. NIH/NIDCR grant DE08715.