Objective: To investigate the effects on plaque index (PI) scores of manual or electric toothbrush with or without repeated oral hygiene instructions (OHI) and motivation on patients wearing fixed orthodontic appliances. Materials and Methods: One month after the orthodontic fixed appliance bonding on both arches, 60 patients were randomly assigned to four groups; groups E 1 (n 5 15) and E 2 (n 5 15) received a powered rotating-oscillating toothbrush, and groups M 1 (n 5 15) and M 2 (n 5 15) received a manual toothbrush. Groups E 1 and M 1 received OHI and motivation at baseline (T0) and after 4, 8, 12, 16, and 20 weeks (T4, T8, T12, T16, and T20, respectively) by a Registered Dental Hygienist; groups E 2 and M 2 received OHI and motivation only at baseline. At each time point a blinded examiner scored plaque of all teeth using the modified Quigley-Hein PI. Results: In all groups the PI score decreased significantly over time, and there were differences among groups at T8, T12, T16, and T20. At T8, PI scores of group E 1 were lower than those of group E 2 , and at T12, T16, and T20, PI scores of groups M 1 and E 1 were lower compared to those of groups M 2 and E 2 . A linear mixed model showed that the effect of repeated OHI and motivation during time was statistically significant, independently from the use of manual or electric toothbrush.
Conclusions:The present results showed that repeated OHI and motivation are crucial in reducing PI score in orthodontic patients, independent of the type of toothbrush used. (Angle Orthod. 2014;84:896-901.)