13 - A vertical analysis of incisor positioning in adolescent patients treated with fixed orthodontic appliances

Abstract

Introduction

Fixed appliances are thought of being extrusive by nature, but there is no evidence as to if wearing fixed appliances has a significant effect on the vertical position of maxillary and mandibular incisors. The aim of this study is to evaluate vertical skeletal and dental changes in incisor positioning among adolescents treated with fixed orthodontic appliances, utilizing the Case Western Reserve University (CWRU) Vertical Analysis.

Methods

A retrospective case-control design with 30 adolescents (ages 10–15) who completed comprehensive non-extraction orthodontic treatment with full fixed pre-torqued, pre-angulated appliances was included. Subjects receiving any adjunctive vertical control methods, such as TADs, bite turbos, functional appliances, orthopedic expansion, extractions (excluding third molars), or segmental mechanics, were excluded. Each subject was matched to an untreated control by age, sex, and initial dental classification from the Bolton-Brush Growth Study. Vertical incisor changes were quantified using the CWRU Vertical Analysis, which evaluates both skeletal and dental components of vertical correction. Initial and final CBCTs were used to construct lateral cephalograms, and all cephalometric tracings were performed by a single calibrated examiner to ensure consistency. Seven key landmarks were identified: anterior nasal spine (ANS), incisal tip and apex of the maxillary and mandibular central incisors, and the centers of resistance of both incisors. Vertical changes were calculated using six independent variables: maxillary skeletal change, mandibular skeletal change, bodily and tipping movements of both maxillary and mandibular incisors. These changes were then compared to the corresponding control group.

Results

Preliminary results show significant differences between treated and untreated samples, with intrusive movements in the treated sample. No significant differences were found between genders.

Conclusions

The use of fixed appliances have a significant effect on the vertical position of the anterior dentition.