Assessment of Plaque Control by Robot Simulation of Tooth Brushing

Objectives: To demonstrate correlation of tooth cleaning efficiency of a new robot brushing simulation technique with clinical plaque removal.Methods: Clinical programme: 27 subjects received a professional dental cleaning prior to 3-day-plaque-regrowth-interval. Plaque was stained, photographically documented and scored using planimetrical index (Claydon and Addy 1995). The subjects brushed teeth 33-47 with three most recommended brushing techniques (horizontal, rotating, vertical), each for 20s buccally and for 20s orally in 3 consecutive intervals. The pressure was calibrated (3.5N), and the brushing technique was video supported. Two brushes with flat trim and interdental cut were compared (Dr.Best®plus medium(n=13) and Dr.Best®Interdent medium(n=14), GlaxoSmithKline, Germany). Robot programme: The clinical brushing programmes were meticulously transformed to the 6-axis-robot (Kawasaki Robotics, Japan). Artificial teeth 33-47 (KaVo, Germany) were covered with plaque simulating substrate. All brushing techniques were repeated 7 times, and results were scored according to clinical planimetry. All data underwent statistical analysis by t-test, U-test and multivariate analysis. Results: The individual clinical cleaning patterns tooth by tooth as well as their variations are well reproduced by the robot programmes. Differences in plaque removal are statistically significant for the two brushes, for incisors vs. premolars vs. molars and buccally vs. orally. Differences were reproduced in clinical and robot data. Multivariate analysis confirms the higher cleaning efficiency for anterior teeth and for the buccal sites. Rotating technique was superior to horizontal brushing. Molars were more effectively cleaned by the subjects than by the robot. Conclusions: The robot tooth brushing simulation programme showed good correlation with clinically standardized tooth brushing. This new robot brushing simulation programme can be used for rapid, reproducible laboratory testing of tooth cleaning.This study was supported by GlaxoSmithKline and M+C-Schiffer.