The antibacterial efficiency of Chitosan photodynamically activated Phycocyanin, and Morinda Oleifera against S.mutans and the bonding strength between composite resin and caries-affected dentin.

Objective: Evaluation of contemporary disinfection techniques, Moringa Oleifera (M.Oleifera), Phycocyanin activated by photodynamic therapy (PDT), and Chitosan, on S.mutans survival rate and bond integrity of composite to carious-affected dentin (CAD).

Methods: The in vitro study was conducted at King Saud University and concluded within three months. Sixty mandibular teeth with cavities extending to the middle third of the dentin were sterilized. was inoculated onto the CAD surface of twenty samples. The samples were randomly divided into four groups (n: 15) based on various disinfection regimes. Group-1 received 2% CHX, Group-2 Phycocyanin activated by photodynamic therapy (PDT), Group-3 Chitosan, and Group-4 M.oleifera. S.mutans survival rate was calculated. Ten CAD samples from each group were restored using composite. The bond integrity of samples was assessed using a Universal testing machine (UTM) and failure mode using a stereomicroscope. Analysis of variance (ANOVA) and Tukey's Post Hoc test were used to calculate statistical significance (p=0.05).

Results: Group-2 samples subjected to Phycocyanin activated using PDT, displayed minimal survival rate (0.24 ± 0.05 CFU/ml) of S.mutans.Group-1 samples treated with CHX exhibited the highest count of S.mutans (0.69 ± 0.12 CFU/ml). The most robust bond was observed in Group-3 (Chitosan) samples (19.33 ± 0.47 MPa). In contrast, SBS values were lowest in Group-1 (CHX) treated study samples (13.17 ± 1.88 MPa).

Conclusion: Chitosan, Phycocyanin activated by PDT, and Moringa Oleifera extract exhibit potential as viable substitutes for chlorhexidine (CHX) in clinical settings, presenting the possibility of better eradication of S.mutans and greater adhesive strength to CAD.