Comparison between a simplified and a conventional biofilm index in relation to caries activity and gingivitis in the primary dentition

Aim: This was to compare a simplified biofilm index with a conventional one in relation to caries activity and gingivitis in the primary dentition. Study design: Observational, crosssectional. Methods: The sample consisted of 90 children aged 10 to 57 months-old. A single examiner performed all examinations. Two visible biofilm indices, one simplified (BF1) and the other conventional (BF2), were used. Gingival bleeding was assessed after flossing all proximal surfaces and each tooth surface was classified for caries, including non-cavitated lesions. Results: According to BF1, half of the sample (45 -50%) had thick biofilm. BF2 showed a mean value of 21.8% (SD +/- 6.5); 12 (13.3%) children had gingival bleeding and the mean percentage of bleeding surfaces was 0.9% (SD +/- 2.5). Caries was present in 36 (40.0%) children and the mean value of active lesions was 2.1 (SD +/- 4.3). The association between visible biofilm and gingival bleeding was significant (p= 0.01), except when BF1 was associated with the gingival index (p= 0.08). The association between BF1 and BF2 with caries activity was highly significant (p <= 0.001). Conclusion: Both biofilm indices may be used when the outcome being measured is caries. In the primary dentition, though, the conventional index (BF2) is better suited for studies about gingivitis.