Condylar effects with stepwise mandibular advancement versus maximum jumping

Abstract

AIM: To compare, in a prospective clinical study, condylar changes during stepwise mandibular advancement and mandibular maximum jumping. SUBJECTS AND METHOD: The headgear activator group (HGA-S) had stepwise advancement (n = 24, mean age = 11.9 ± 1.2 years) for 4 mm every 3 months with individualised bite opening following the condylar translatory pathway, whilst the HGA-M group (n = 31, mean age = 11.2 ± 1.5 years) had maximum jumping to edge-to-edge with 6 mm interincisal opening. Active treatment was 12 months (T0-T12) for the HGA-S group and 6 months (T0-T6) for the HGA-M group followed by 6 months (T6-T12) of reduced appliance wear and headgear cessation. Superior and posterior condylar changes were analysed from full mouth opening lateral cephalograms (Pancherz and Hägg, 1985) taken at the start (T0) and 6 (T6) and 12 (T12) months after treatment. The results were adjusted to the same observation lengths. Growth changes were obtained from the untreated control group, i.e. HGA-M group (10.3 ± 2.4 years) before treatment. RESULTS: There was similar sagittal condylar treatment effect with both devices during the initial (T0-T6), late (T6-T12) and total treatment (T0-T12) phases. There was no statistically significant vertical condylar effect with HGA-M during either the initial (T0-T6) or late (T6-T12) phases, whereas HGA-S resulted in a statistically significant effect during both phases. CONCLUSION: Both mandibular maximum jumping and stepwise advancement resulted in a sagittal condylar effect. However, there was a vertical condylar effect only with mandibular stepwise advancement. This indicates that the amount and frequency of bite jumping seem to be decisive factors for treatment effects on the condyles.