Comparison of skeletal and dentoalveolar effects of herbst and monoblock appliances used in during different growth periods

Objective: The aim of this retrospective study was to compare changes in skeletal, dentoalveolar and soft tissues according to the growth and developmental stages and treatment methods of Class II anomalies in which functional therapy was applied by Herbst and monoblock appliances. Method: Between the years 2012-2018 the records of 279 patients with mandibular retrognathia whose functional treatment completed were examined. The study included the remaining Herbst (H) group 59, monoblock (M) group and 59 individual radiographs after the inclusion criteria were applied. Cephalometric and hand wrist radiographs of the individuals included in the study were examined and skeletal development periods were determined. Individuals were divided into peak period (P) and postpeak (PP) periods and a total of four study groups were designed. The Herbst peak (HP) group consisted of 17 individuals (mean age: 13.02 ± 1.48 years), while the Herbst postpeak group (HPP) consisted of 42 individuals (mean age: 13.93 ± 1.28 years); the monoblock peak (MP) group consisted of 43 individuals (mean age: 12.74 ± 1.42 years), and the monoblock postpeak (MPP) group consisted of 16 individuals (mean age: 12.88 ± 0.98 years). Intra-group changes in cephalometric measurements were performed by paired t-test; MANOVA test was used to compare the inter group changes. Results: The parameters of A1-NB (mm), A1-NBº and IMPAº were significantly higher in the Herbst groups than the monoblock groups. It was determined that maxillary growth was restricted in all groups. Increases were observed in all dimensional and positional measurements of the mandible and similar increases were obtained in the post pubertal period. Conclusion: It was concluded that the Herbst appliance caused more protruded teeth lower incisors than those of the monoblock appliance. In the peak period, the skeletal effect of the monoblock appliance is higher than the Herbst appliance on overjet improvement and the skeletal effect of the Herbst and monoblock appliances in the postpeak period is similar. Key Words : Mandibular retrognathia, monoblock appliance, Herbst appliance, late term functional treatment