Direct and Transdentinal (Indirect) Antibacterial Activity of Commercially Available Dental Gel Formulations against Streptococcus mutans

OBJECTIVE: To evaluate the direct and transdentinal (indirect) agar diffusion antibacterial activity of different commercially available antibacterial dental gel formulations against Streptococcus mutans. MATERIALS AND METHODS: The commercially available dental gel formulations were Corsodyl® (COG, 1s% chlorhexidine), Cervitec® (CEG, 0.2s% chlorhexidine s+ 0.2s% sodium fluoride), Forever Bright® (FOB, aloe vera), Gengigel® (GEG, 0.2s% hyaluronic acid), 35s% phosphoric acid gel and distilled water (control). Direct agar diffusion was performed by isolating three wells from brain-heart infusion agar plates using sterile glass pipettes attached to a vacuum pump and adding 0.1 ml of the gels to each well. Transdentinal (indirect) agar diffusion was performed by applying gel to 0.2- and 0.5-mm-thick human dentin discs previously etched with phosphoric acid and rinsed with distilled water. Zones formed around the wells and the dentin discs were measured and analyzed using Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction (p < 0.01). RESULTS: Direct agar diffusion tests showed significant differences among all gel formulations (p < 0.01) except for COG and CEG (p > 0.01). COG and CEG exhibited higher antibacterial effects compared to FOB and GEG (p < 0.01) in both direct and transdentinal (indirect) testing procedures. GEG did not show any antimicrobial activity in transdentinal (indirect) testing. CONCLUSION: Commercially available dental gels inhibited S. mutans, which may indicate their potential as cavity disinfectants.