LAUSR

BACKGROUND Assessment of orthodontic treatment outcomes such as treatment duration in patients with hypodontia are lacking. OBJECTIVES To assess the overall treatment duration of cases of bilateral absent upper lateral incisors treated with either orthodontic space closure (SC) or space opening (SO). The secondary aim was to determine factors which influence overall treatment duration. SUBJECTS AND METHODS A retrospective cohort study was undertaken within the Orthodontic department at Kings College Hospital NHS Foundation Trust. Consecutively treated patients between 2008 and 2018 with bilateral absent upper lateral incisors were identified from clinic lists, clinical logbooks, and multidisciplinary clinics. All study data variables were collected by a single investigator using a pre-specified data collection sheet. RESULTS In total, 52 cases were included, 29 in the SC group and 23 in the SO group. Overall non-extraction treatment was favoured (P = 0.001) with differences in restorations provided post-treatment evident (P = 0.01). Although not statistically significant, the mean overall orthodontic treatment duration was less in the SC group 25.7 months (SD 7.6) compared to the SO group 27.4 (SD 6.1). Overall treatment duration was reduced if treatment was carried out on an extraction basis (-7.02, 95% CI: -11.93, 2.11, P = 0.01) but increased as the amount of crowding in the lower arch increased (0.89, 95% CI: 0.08, 1.71, P = 0.03). CONCLUSIONS Within the study limitations, there is no difference in the overall treatment duration between both treatment approaches. Treatment duration is reduced in both SO or SC treatment plans if extractions are undertaken. The presence of lower arch crowding increases the duration of treatment.