Oral hygiene frequency and presence of visible biofilm in the primary dentition.

The purpose of this study was to associate oral hygiene frequency and presence of visible biofilm in the primary dentition. The sample consisted of 90 children, aged up to 4 years old, outpatients of the University Hospital of the Rio de Janeiro State University. The examinations were carried out in a dental office by a single trained examiner who was aided by an assistant. The parents answered a structured questionnaire about oral hygiene methods and frequency. Two biofilm indices, one simplified (BF1) and the other conventional (BF2), were used. BF1 classifies biofilm as absent, thin or thick, in anterior and/or posterior teeth, and provides a score for the patient, whereas BF2 classifies biofilm as absent or present, provides scores for three surfaces of each tooth and the final score is the percentage of tooth surfaces with biofilm. More than half of the parents (51 - 56.7%) reported they cleaned their child's teeth at least twice a day, while 7 (7.8%) had never cleaned their child's teeth. BF1 revealed that 12.2% (11) of the children had no visible biofilm, 37.8% (34) had thin biofilm in anterior and/or posterior teeth, 27.8% (25) had thick biofilm in anterior or posterior teeth and 22.2% (20) had thick biofilm in both anterior and posterior teeth. BF2 revealed a mean value of 21.8% (s.d. 16.5). No statistically significant correlations were found between oral hygiene frequency and the two biofilm indices (p > 0.05), indicating that oral hygiene frequency was not associated to oral hygiene quality in the evaluated sample.