Harmonization of visible posterior teeth width after orthodontic treatment

Objectives: To determine whether successfully treated orthodontic patients exhibit similar visible posterior teeth width values regardless of initial malocclusion type, and to evaluate the influence of age and sex on this variable.
Methods: Orthodontically treated patients (n=60; 20/group; age 16–35 y; mean 23.8±5.2 y; median 22 [IQR:21–26]) with Class I, II, and III malocclusions were photographed under standardized conditions using a 1-cm adhesive calibration strip to control magnification error. Frontal full-face smiling images were analyzed using image-analysis software to quantify visible posterior teeth width. Differences were assessed using one-way ANOVA (group), independent t-tests (gender), and Spearman rank-order correlation (age).
Results: No significant difference in visible posterior teeth width was observed among the three malocclusion groups (p >0.05). Mean visible posterior teeth width was highest in Class I (52,22±2,48mm) and
lowest in Class III (51,53±2,85mm) (F (2)= 0,322, p =0.726). Male subjects showed a nonsignificant trend toward greater visible posterior teeth width compared to females in Class I (t(18)=1.119, p=0.278), Class II (t(18)=-0.544, p=0.593) and Class III (t(18)=0.702, p=0.491). Age showed nonsignificant correlations with visible posterior teeth width, with slight negative trend in Class I (R(20) = 0.064, p = 0.789) and Class II (R(20) = 0.017, p = 0.945), and a nonsignificant positive trend in Class III (R(20) = 0.433, p = 0.057).
Conclusions: Orthodontic treatment harmonizes smile parameters, producing comparable visible posterior teeth width across malocclusion types. Comprehensive smile analysis remains essential for accurate diagnosis and optimal esthetic treatment outcomes.