Background: Malocclusion can affect the oral health-related quality of life (OHRQoL). The influence of the orthodontic treatment need (OTN) and the type of brackets on OHRQOL is not clear.
Objectives: The aim of the present study was to determine the relationships between OTN and the bracket type and OHRQoL during the first 6 months of orthodontic treatment (OT) in adult patients.
Material and methods: This cohort study was conducted at the Department of Orthodontics of a private university. A total of 216 patients aged ≥18 years participated in the study (106 patients with conventional brackets and 110 with self-ligating brackets). The OHRQoL was evaluated using the 14-item Oral Health Impact Profile (OHIP-14) at 5 time points - before OT (T0), and at 24/48 h (T1), 1 month (T2), 3 months (T3), and 6 months (T4) after the installation of the orthodontic appliance. The OTN was evaluated with the dental aesthetic index (DAI) by 2 previously calibrated operators. For the statistical analysis, the χ2 test and the Mann-Whitney U test were used. Additionally, Poisson regression models were performed.
Results: The evidence of an association between OHRQoL and OTN was found only at T3 (p = 0.0095). No association was found between OHRQoL and the bracket type. However, in the regression models, OHRQoL was statistically significantly worse at T3 in the group with a greater OTN (IRR (incidence rate ratio) = 1.34; 95% CI (confidence interval): 1.21;1.48) and at T4 in the self-ligation group (IRR = 1.23; 95% CI: 1.12;1.36).
Conclusions: The OHRQoL was affected in the same way at the beginning of OT, regardless of OTN and the bracket type used. However, a worse OHRQoL was observed at 3 months in subjects with greater OTN and at 6 months in patients with self-ligating brackets.
Keywords: malocclusion; orthodontic appliances; orthodontic brackets; orthodontics; quality of life.