Purpose: To evaluate the association between orthodontic treatment with fixed appliances and periodontal health during treatment by examining gingival inflammation indices and saliva properties.
Materials and Methods: Thirty consecutive orthodontic patients, aged 11–18 years old, who were eligible for fixed orthodontic appliances, were included in the study. Plaque index (PI), gingival index (GI), salivary pH and flow rate were recorded at three timepoints: immediately before placement of orthodontic fixed appliances (T0), and 1 (T1) and 3 months (T2) after bonding.
Results: The hypothesis that PI would remain constant across timepoints was rejected. PI increased over time (0 to 1 scale, T1-T0: mean diff. = 0.10, 95% CI = 0.03, 0.18, p = 0.01; T2-T0: mean diff. = 0.16, 95% CI = 0.08, 0.24, p < 0.001). On the other hand, GI changed statistically significantly over time (p = 0.05). Patients’ age was not a predictor for PI change (p = 0.93), but it was for GI (p = 0.01). As anticipated, average PI was found to be higher for the mandibular dentition by 0.10 (95% CI = 0.04, 0.16) and the labial surfaces of teeth of both jaws by 0.51 (95% CI = 0.45, 0.57).
Conclusions: Within the framework of the current study, orthodontic treatment appeared to affect the periodontal health of patients, but the changes were clinically negligible and not consistently statistically significant.