The Herbst appliance and the Activator: influence of the vertical facial pattern

Christopher Turnock,Michael G Woods

doi:10.21307/aoj-2020-120

Abstract

Abstract Aim To compare the effects of the Herbst appliance and the Activator at the completion of two-phase treatment, with respect to the vertical facial pattern (VFP) and to identify possible predictors of treatment effect. Materials and methods Pretreatment, post-treatment and overall cephalometric change data were used to assess the dental and skeletal effects. Results for the change in mandibular length were also compared with changes reported for an untreated external control group. Results Clinically significant dental and skeletal changes (including mandibular incisor proclination and overjet reduction) were characteristics of both treatment methods. Any increases in mandibular length and chin prominence were not greater than those expected following natural growth. The pretreatment VFP remained essentially unaltered, while mean changes as a result of treatment were similar for brachyfacial, mesofacial, and dolichofacial subjects. No predictive factors were identified. Conclusions Clinicians are advised to expect significant overjet reduction and mandibular incisor proclination with either treatment method. Significant skeletal change may be observed in growing subjects; however, any increase in mandibular length or chin projection is not likely to be beyond the limit set by nature. While there will be some individual variation, no significant long-term alteration in the pretreatment vertical facial pattern should be expected with either treatment. Long faces will remain long and short faces will remain short.

Highlights

The orthodontic and orthopaedic treatment of the developing Class II occlusion and skeletal base has been an area of much controversy
Class II malocclusions may be separated into maxillary and mandibular dental and skeletal components, with a general lack of homogeneity in the presenting dentofacial morphology observed.[1]
The pretreatment differences in facial axis measurements for the two treatment groups were still present in the post-treatment analysis

Summary

Introduction

The orthodontic and orthopaedic treatment of the developing Class II occlusion and skeletal base has been an area of much controversy. Class II malocclusions may be separated into maxillary and mandibular dental and skeletal components, with a general lack of homogeneity in the presenting dentofacial morphology observed.[1] It is, recognised that the majority of Class II cases involve a component of mandibular retrognathia.[2] It is this realisation that has prompted extensive research into the use of functional appliances and two-phase orthodontic treatment. Successful individualised treatment planning relies on an analysis of skeletal and dental components in all three dimensions. Growth status,[5,6] as well as the underlying vertical facial pattern (VFP)[1,7] and associated growth rotation[8,9,10,11,12] may play significant roles in overall treatment effect and success

Objectives

Methods

Results

Discussion

Conclusion