Comparison between two antimicrobial photodynamic therapy protocols for oral candidiasis in patients undergoing treatment for head and neck cancer: A two-arm, single-blind clinical trial

•No differences in microorganisms were observed between groups.•In both groups, there were low rates of treatment failure.•Methylene blue reduced the number of infected anatomical sites. Purpose This study aimed to compare the efficacy of Antimicrobial Photodynamic Therapy (aPDT) with 300 µmol/L of methylene blue and 8 µmol/L of curcumin on oral candidiasis patients with HNSCC undergoing treatment. Methods A two-arm, single-blind clinical trial was performed. Following verification for eligibility (n = 447), 108 patients were included in the study. The study consisted of a group that received aPDT with methylene blue (n = 57) and another that received aPDT with curcumin (n = 51). The patients rinsed their mouths with an aqueous solution of 300 µmol/L of methylene blue and 8 µmol/L of curcumin in four sessions, and then the lesion was scraped for the subsequent RT-qPCR. The primary outcome was that no cure was presented for oral candidiasis after treatment. The secondary result was reducing the number of sites affected by oral candidiasis. Results There was no difference in treatment failure evaluated by the necessity of drug prescription or Candida sp DNA quantification. However, clinically the methylene blue protocol reduced the number of infected anatomical sites compared to the curcumin protocol. Conclusion Methylene blue aPDT reduced the number of infected anatomical sites compared to curcumin.