Evaluation of in vitro Streptococcus mutans and Actinomyces naeslundii attachment and growth on restorative materials surfaces

Abstract

Background: Restorative materials have varying surface characteristics from natural tooth, which may affect oral‐bacterial surface attachment/growth. This study examined 48‐h Streptococcus mutans (Sm) or Actinomyces naeslundii (An) growth on various restorative materials and tooth surfaces.

Methods: The quantity and viability of 48‐hour‐old Sm and An growth on polished (180‐ or 1200‐grits), saliva‐coated resin composite (RC), glass ionomer cements (GIC), resin‐modified GIC (R‐GIC), GIC containing casein phosphopeptide–amorphous calcium phosphate (3% (w/w), CPP‐ACP GIC), amalgam or tooth blocks (5 × 5 × 1 mm3) were examined.

Results: Rough‐polished (arithmetical mean deviation of the assessed surface roughness profile (Ra): 1.50–1.75 µm) material surfaces revealed relatively higher proportion of inorganic, positively charged surface components ((Si + Al)/C) and greater quantity of surface attached bacteria than smooth polished (Ra: 0.20–0.35 µm) material groups (P < 0.001). Less Sm and An were observed on tooth, and smooth polished GIC and CPP‐ACP GIC surfaces than on resin‐based materials (RC, R‐GIC) and amalgam (P ≤ 0.003). Viability of Sm was found to be lower on amalgam surfaces (P < 0.001), whereas that of An appeared lower on both amalgam surfaces and rough CPP‐ACP GIC surfaces (P ≤ 0.033).

Conclusion: Surface roughness exerted a pronounced effect on in vitro growth/attached Sm/An quantity but may not have an impact on bacteria viability. Interestingly, despite smoother surfaces of various materials tested, fewer Sm/An were observed attaching on tooth surfaces.