Adhesion of Streptococci to various orthodontic composite resins

This investigation aimed to determine quantitatively the adhesion of Streptococcus mutans and Streptococcus sobrinus to orthodontic composite resins that were tested simultaneously using radio-markers.

Seven orthodontic composite resins were classified into seven groups: BeautyOrtho Bond (GI), Blugloo (GII), Enlight (GIII), Grengloo (GIV), Kurasper F (GV), Transbond CC (GVI) and Turbo Bond II (GVII). Thirty 4 x 4 x 1 mm blocks of each orthodontic composite resin were made (a total of 210 blocks). Both Streptococcus species were cultivated independently. For the quantitative analysis, radioactive markers were used to codify the bacteria ((3) H for Streptococcus mutans and (14) C for Streptococcus sobrinus). The blocks were submerged in a solution with microorganisms previously radiolabelled for 2 hours at 37 °C in constant movement. The blocks were placed in a combustion system to quantify the Streptococcus adhering to the surface of the materials by capturing the residues and measuring the radiation.

Significant differences in bacterial adhesion were found among the groups. The lowest significant scores for both microorganisms were observed in GIII.

The orthodontic composite resin evaluated in GIII exhibited the lowest adhesion of Streptococcus mutans and Streptococcus sobrinus, which may reduce enamel demineralization and the risk of white spot lesion formation.