In vitro assessment of the antibacterial properties of novel chemomechanical caries removal agents and their impact on bonding performance to resin composite restorations.

OBJECTIVES

To assess the antibacterial efficacy of novel bromelain-containing chemomechanical caries removal (CMCR) agents and their effect on the bonding strength of residual dentine to an adhesive resin composite restoration.

METHODS

The antibacterial efficacy of three formulated CMCR gels, comprising 30 % bromelain (F1), 30 % bromelain with 0.1 wt.% chloramine-T (F2), and 30 % bromelain with 1.5 % chlorhexidine (F3), was evaluated in comparison to Brix 3000, specifically against Streptococcus mutans and Lactobacillus acidophilus species. A total of 120 extracted permanent molars exhibiting natural carious lesions were randomly allocated into six groups based on excavation techniques; hand excavation, rotary excavation, Brix 3000, F1, F2, and F3. The microshear bond strength (µSBS) of the residual dentine to resin composite was assessed after two-time intervals. The morphological assessment was conducted using scanning electron microscopy (SEM).

RESULTS

F3 demonstrated the most pronounced statistically significant antimicrobial efficacy against both bacterial species (p < 0.001), as well as the highest statistically significant immediate µSBS to the residual dentine (p < 0.001). In contrast, F2 exhibited the highest µSBS mean value post aging (p < 0.001), along with the greatest percentage of mixed and cohesive failures. This was accompanied by the presence of a well-integrated hybrid layer and numerous elongated resin tags within the residual dentine.

CONCLUSION

The novel bromelain-based CMCR gels, particularly when combined with chlorhexidine, demonstrated a remarkable antimicrobial efficiency. In contrast, the formulation containing chloramine-T exhibited superior prolonged bonding performance.

CLINICAL SIGNIFICANCE: These novel formulations present a promising strategy for caries management and enhance the longevity of adhesive restorations.