Initial bacterial adherence and biofilm formation on novel restorative materials used in paediatric dentistry

Objective: To evaluate the initial bacterial adherence and biofilm formation on novel restorative materials in paediatric dentistry and compare the results to stainless steel crown and primary enamel. Materials and methods: Twenty-five samples (Diameter = 4 mm) from five restorative materials (Tetric Power Fill light cured for 3 s or 10 s, Fuji II LC, Equia Forte HT Fil, Cention Forte, Stainless-steel crown) and primary enamel were prepared. Four samples served for recording of surface roughness (Ra) using a contact profilometer, 21 samples were incubated in stimulated human saliva for 2 h (initial bacterial adherence) and 72 h (biofilm formation) and served to determine ion releasing and bacterial growth. After 2 and 72 h, the number of colonyforming units (CFU) per ml was counted and expressed in Log10 CFU/ml. Data were analysed with two-way ANOVA and Tuckey's multiple comparisons test (p < 0.05). Results: All tested materials showed similar initial bacterial adherence (p > 0.1). Stainless steel crown showed statistically significantly less biofilm formation than all other tested materials (p <= 0.02), except for Fuji II LC (p = 0.06). In terms of biofilm formation, the differences between all tested materials were not statistically significant (p >= 0.9). Significance: Novel restorative materials in paediatric dentistry show similar initial bacterial adherence and biofilm formation. However, compared to other restorative materials, stainless steel crowns demonstrate the lowest level of biofilm formation. Ion-releasing materials may not necessarily show better antimicrobial properties than conventional materials.