Anterior tooth wear and retention type until 5 years after orthodontic treatment

Abstract

Objectives. To study occlusal wear of anterior teeth in orthodontic patients retained with different retainers until 5 years post-treatment, and to investigate whether type of retention influences occlusal wear. Material and methods. Orthodontic patients (n=222), aged 15 years maximally at the start of treatment, were followed until 5 years post-treatment. In the maxilla, a retainer bonded on all six teeth or a removable retainer was used; in the mandible, a lingual retainer was bonded on all anterior teeth or on canines only. Dental casts were analyzed before treatment (T₀), after treatment (T₁), and 5 years post-treatment (T₅). Incisal and canine wear were scored by applying a grading scale. Intercanine width, overjet, and overbite were measured with an electronic caliper. Statistics used were: Paired samples t-test for differences over time; Pearson correlation coefficients for associations between wear and retention type; and backward linear regression for influence of retention type on wear. Results. There was an increase in wear during all time periods and for all teeth. From T₀ to T₅ an increase in maxillary intercanine width and maxillary retention had an effect on changes in canine wear. Incisal wear was associated with an increase in upper intercanine width (T₁–T₅). For both arches, an increase in maxillary intercanine width during treatment was associated with less progression of canine and incisal wear, but the explained variance was low, 13.4% and 19.3%, respectively. Conclusions. Retention type and, occasionally, an increase in intercanine width influence anterior teeth wear post-treatment. However, the clinical significance and impact of the examined retention methods on occlusal wear are small.