Presence of cariogenic streptococci on various bracket materials detected by polymerase chain reaction

To determine the in vivo presence of Streptococcus mutans and Streptococcus sobrinus on different bracket materials and to correlate the prevalence with the Visible Plaque Index (VPI) and the Gingival Bleeding Index (GBI).

Orthodontic brackets made of different materials (stainless steel, gold, ceramic, plastic) were bonded to the upper and lower second premolars in 40 subjects receiving fixed orthodontic appliances. After 30 days, the brackets were debonded and the presence of S. mutans and S. sobrinus on the brackets was determined using the polymerase chain reaction (PCR) technique. The VPI and GBI were recorded and the relationship between the prevalence of the streptococci and the level of oral hygiene was calculated.

There were fewer S. mutans and S. Sobrinus over the surface of gold and stainless steel brackets compared with the plastic and ceramic brackets. A statistically significant difference was observed in S. mutans and S. sobrinus prevalence between the metal brackets and the aesthetic brackets. However, there were no statistically significant differences in S. mutons and S. Sobrinus prevalence when the gold and stainless steel brackets were compared. Comparison between the plastic and ceramic brackets revealed a similar finding. Furthermore, a significant correlation was found between the in vivo prevalence of S. mutans and S.sobrinus and the oral hygiene indices (p < 0.05), suggesting that the oral hygiene indices could be a good indicator of S. mutans and S. sobrinus prevalence.

Since microbial adhesion is greater on aesthetic brackets, good oral hygiene during treatment should be emphasised.