RESUMEN
Background: Streptococcus mutans is a Gram-positive opportunistic bacterial pathogen and that causes dental caries and then restorative treatment remains the best clinical practice approach to repair and prevent dental caries. Aims: This study compared the antimicrobial performance of resin modified glass ionomer cement (RM-GIC) and ACTIVA restoratives by evaluating the S. mutans count, pH levels, and plaque index (PI) scores before and on the 7th day of restoration, and then determined the antimicrobial activities against S. mutans ATCC 25175 in both restoratives in vitro. Materials and Methods: Seventy-eight eligible Saudi female participants, with class II carious lesions, were randomly distributed into RM-GIC and ACTIVA restorative groups. We evaluated the S. mutans count by the serial dilution technique and salivary pH by using a portable pH meter. The PI scores were determined by Silness-Löe method and the antibacterial activity by the agar well diffusion method. Statistical analysis of normality distribution was performed with the Kolmogorov-Smirnov and the difference between groups was an analysis by paired t-test. In addition, the independent sample was compared with the independent samples t-test. Results: Both groups reduced the S. mutans count, pH acidity, and PI scores, and this reduction was statistically significant on the 7th day of restoration (P < 0.05), preference for ACTIVA. The in vitro antibacterial activity against S. mutans ATCC 25175 showed a non-significant difference between both bioactive restorative materials (P < 0.05). Conclusion: The novel application of ACTIVA restorative material is a promising option for patients at risk of caries.