Outcome quality of Class II division 1 Herbst-multibracket appliance treatment: influence of pretreatment Class II severity and skeletal maturity

Abstract

Summary Background No reliable predictive factors for treatment (Tx) success and outcome quality in Class II:1 Tx have been identified yet. Objective To assess the influence of pre-Tx Class II severity and skeletal maturity on outcome quality after Herbst-multibracket appliance (MBA) Tx. Subjects and methods All Class II:1 patients who completed Herbst-MBA Tx between 1986 and 2014 at University of Giessen, Germany. Pre-Tx (T0), post-Tx (T1), and (if available) post-retention (≥24 months; T2) study casts were evaluated using the Peer Assessment Rating (PAR) index and the Ahlgren scale. Three occlusal severity (mild, moderate, and severe) and four skeletal maturity (pre-peak, peak, post-peak, and adult) subgroup categories were defined. Results Four hundred eight-five patients (age at T0: 14.4 ± 3.2 years) could be evaluated; post-retention (T3) data were available for 230 patients. For the total sample, the median PAR score was 32.4 ± 8.85 at T0, 8.0 ± 4.52 at T1, and 8.8 ± 5.11 at T2. Very low correlations between the subgroup categories (occlusal severity/skeletal maturity) and PAR-score reduction were detected both during Tx (r = 0.12/r = 0.05) and the total observation period (r = 0.17/r = 0.03). The overall outcome quality according to Ahlgren was: 17.0% excellent, 34.8% good, 43.8% acceptable, 2.2% unacceptable, and 2.2% not assessable. The association with the subgroup categories was: p = 0.019 (occlusal severity)/p = 0.820 (skeletal maturity). Limitations Retrospective study design with follow-up data was not available from all subjects and no data from untreated controls. Tx was performed by several physicians using different kind of MBAs. Conclusion Class II:1 Herbst-MBA Tx is an effective and successful Tx approach irrespective of pre-Tx skeletal maturity but dependent—to a certain extent—on Class II severity. Thus, when considering a Herbst appliance for Class II correction, neither of the two variables should considerably limit the indication.