Factors affecting dental biofilm in patients wearing fixed orthodontic appliances

Background: The aim of this study is to investigate the amount and the distribution of biofilm in patients wearing fixed appliances and its relation with age, gender, frequency of tooth brushing, and patient motivation. Methods: The sample comprised 52 patients (15.5 ± 3.6 years old, 30 females and 22 males) wearing fixed orthodontic appliances. Dental biofilm was assessed using a modified plaque index (PI). A questionnaire was used to collect patient's information, including gender, age, treatment motivation, and frequency of tooth brushing. Results: Gingival (PI score = 0.9 ± 0.7), mesial (0.8 ± 0.6), and distal (0.8 ± 0.5) areas accumulated more biofilm than occlusal areas (0.3 ± 0.3) (P < 0.038). The maxillary lateral incisors (1.1 ± 0.8) and maxillary canines (1.0 ± 0.8) had more biofilm than other teeth (P < 0.05). The maxillary arch (0.8 ± 0.7) had significantly more biofilm than mandibular arch (0.6 ± 0.6) (P = 0.042). No significant difference was found between the right side (0.7 ± 0.7) and left side (0.7 ± 0.6) (P = 0.627). Less biofilm was found in females (0.6 ± 0.5), adults (0.3 ± 0.3), and "self-motivated" patients (0.3 ± 0.3), compared with males (0.9 ± 0.5), children (0.8 ± 0.6), and "family-motivated" patients (1.1 ± 0.5) (P < 0.001). The amount of biofilm was associated with self-report of the frequency of daily tooth brushing (P < 0.001). Conclusions: Patients wearing fixed orthodontic appliances have the highest biofilm accumulation on the maxillary lateral incisors and maxillary canines, particularly in the gingival area and areas behind arch wires. Less biofilm was observed in female and adult patients and in those who were self-motivated and brushed their teeth more often.