In vitro evaluation of Streptococcus mutans adhesion on prefabricated primary crowns using colony-forming unit analysis and scanning electron microscopy: a pilot study

Early childhood caries is one of the most common oral health problems in children, and in cases of extensive tooth coronal destruction, prefabricated crowns are considered an effective and necessary treatment option. The aim of this in vitro pilot study was to evaluate Streptococcus mutans adhesion to prefabricated primary crowns compared with natural primary teeth using CFU analysis, supplemented by scanning electron microscopy assessment. A statistically significant difference in mean microbial plaque adhesion was observed among the study groups ( p = 0.020). Fiberglass-reinforced resin crowns exhibited the lowest bacterial adhesion (39.71 ± 12.38 CFU/mL), whereas zirconia crowns (66.00 ± 20.22 CFU/mL) and primary teeth (69.14 ± 23.00 CFU/mL) showed higher values. Post hoc analysis revealed significantly lower bacterial adhesion on fiberglass-reinforced resin crowns compared with zirconia crowns ( p = 0.049) and primary teeth ( p = 0.024). No statistically significant differences were observed among zirconia crowns, stainless steel crowns, and primary teeth. SEM observations were consistent with the quantitative findings. Under the conditions of this in vitro study, fiberglass-reinforced resin crowns exhibited lower Streptococcus mutans biofilm formation than zirconia crowns and primary teeth. Further studies are required to determine the clinical relevance of these findings.