Effect of Anti-caries Dental Adhesive on the Multi-species Biofilms

Objectives: This study aimed to develop antibacterial adhesive containing dimethylaminododecyl methacrylate(DMADDM) and poly(amidoamine) dendrimer (PAMAM), and to investigate the effect of a novel anti-caries adhesive on different bacterial in controlled muti-species biofilms for the first time.
Methods: Anti-caries adhesive was obtained by incorporating DMADDM and PAMAM, and Streptococcus mutans, Streptococcus gordonii, and Streptococcus sanguinis were chosen to form multi-species biofilms. Microtensile bond strength test was performed to study the dentin bond strength of the adhesive in different groups. Lactic acid assay and MTT assay were conducted to study the metabolic activity of the biofilms. Exopolysaccharide (EPS)/bacteria volume ratio measured by confocal laser scanning microscopy (CLSM) was performed to determine the EPS production of the biofilms. The scanning electron microscope imaging and dead/live volume ratio decided by CLSM were used to study the biomass. The TaqMan realtime polymerase chain reaction were used to study the proportion change in multi-species biofilms of different groups.
Results: The results showed that incorporating PAMAM and DMADDM into adhesive had no adverse effect on the dentin bond strength. The 1% PAMAM and 5% DMADDM adhesive group decreased the metabolic activity noticeably, and had higher dead/live volume ratio in biofilm, compared with control group (P< 0.05). EPS was reduced significantly in 1% PAMAM and 5% DMADDM group (P< 0.05). The biofilm had a more healthy development tendency after the regulation of PAMAM and DMADDM.
Conclusions: In conclusion, adhesives containing DMADDM and PAMAM had remarkable antimicrobial properties and biological remineralization potentials, promising for anti-caries clinical applications and contributing to a better management of secondary caries.