Evaluation of the Use of Acai ( Euterpe oleracea Martius) for Carious Dentin Disinfection, Combined or Not with Antimicrobial Photodynamic Therapy

Objective: To investigate the effectiveness of the acai photosensitizer ( Euterpe oleracea Martius), combined or not with low-intensity laser, in reducing Streptococcus mutans in carious dentin. Background: Due to its high penetration power and coloring ability, acai presents a promising and unexplored option for use as a photosensitizer in antimicrobial photodynamic therapy. Methods: We selected 60 permanent third molars and exposed their coronal dentin. After producing dentin carious lesions, we randomly divided the teeth into four groups ( n = 15 each): C (control)—no disinfection; AC (acai)—acai photosensitizer application; AC + BL (acai + laser)—acai photosensitizer application and irradiation with low-intensity blue laser diode (Therapy); and BL (laser)—low-intensity blue laser diode (Therapy) application. All carious tissue was collected post-protocol application. Total viable bacterial count was determined after 2 days of incubation. Micro-computed tomography was used for qualitative analysis of carious lesions through observation of a carious tooth (control group). Scanning electron microscopy (SEM) was used for qualitative analysis of carious tissue disinfection using different protocols. Results were analyzed using the Kruskal–Wallis test (Student–Newman–Keuls). Results: The cariogenic challenge produced a carious lesion measuring 17.14875 mm 3 , located in deep dentin close to the pulp. The AC + BL group showed the most significant reduction in S. mutans count ( p < 0.0001), followed by the AC group ( p = 0.0055). The BL group showed no significant reduction in S. mutans count ( p = 0.2122). SEM analysis showed that AC + BL promoted dentin disinfection, with exposed dentinal tubules. The percentage reduction in S. mutans count was: BL (35.75%), AC (63.41%), and AC + BL (92.68%). Conclusions: The AC + BL group showed significantly better results than the AC group alone. The acai photosensitizer, with or without antimicrobial photodynamic therapy, is indicated for carious dentin disinfection.