Could chlorhexidine be an adequate positive control for antimicrobial photodynamic therapy in- in vitro studies?

Author(s)

Chaves Lamarque, Giuliana Campos ^[1] ; Cusicanqui Mendez, Daniela Alejandra ^[1] ; Gutierrez, Eliezer ^[1] ; Dionisio, Evandro Jose ^[1] ; Andrade Moreira Machado, Maria Aparecida ^[1] ; Oliveira, Thais Marchini ^[1] ; Rios, Daniela ^[1] ; Cruvinel, Thiago ^[1]

Affiliation

^[1] Univ Sao Paulo, Bauru Sch Dent, Dept Pediat Dent Orthodont & Publ Hlth, Alameda Dr Octavio Pinheiro Brisolla 9-75, BR-17012901 Bauru, SP - Brazil

• Document type: Journal article
• Source: Photodiagnosis and Photodynamic Therapy; v. 25, p. 58-62, MAR 2019.
• Web of Science Citations: 2

Abstract

Background: Chlorhexidine digluconate (CHX) is commonly applied as positive control of new antimicrobials, because it is considered the gold-standard for chemical plaque control. The aim of this study was to compare the effect of treatments with curcumin-mediated aPDT and CHX in relation to the viability of specific microorganism groups in two distinct times (immediately and 24 h later). Methods: Dentin caries microcosms were grown on bovine dentin discs (37 degrees C, anaerobiosis) for 3 days in the Active Attachment Amsterdam Biofilm Model. The biofilms were treated with 300 mu M curcumin and 75 J.cm(-2) LED, or 0.06% and 0.12% CHX. Then, total microorganisms, total streptococci, mutans streptococci, and total lactobacilli counts were determined. The statistical analysis was conducted by Kruskal-Wallis and post-hoc Dunn's tests (P < 0.05). Results: Curcumin-mediated aPDT (C + L + ), 0.06% and 0.12% CHX reduced mutans streptococci counts (0.19, 0.10 and 0.07 log10 respectively) in the immediate analysis. After 24 h, it was observed a re-growth of microorganisms treated by curcumin-mediated aPDT, whereas both CHX concentrations demonstrated a decrease of the viable microorganisms. Conclusion: This study confirmed the substantive effect of CHX and the immediate effect of aPDT. The use of a neutralizer solution was important to block the substantivity of CHX and permit its fair comparison with aPDT, allowing its use as a positive control in further studies. (AU)

• FAPESP's process: 14/10897-0 - Effect of antimicrobial photodynamic therapy on dentin caries microcosms
• Grantee: Thiago Cruvinel da Silva
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/24962-4 - Comparison between the antimicrobial effects of Photodynamic Antimicrobial Therapy mediated by curcumin and chlorhexidine on microcosms of dentin caries lesions
• Grantee: Eliézer Gutierres
• Support Opportunities: Scholarships in Brazil - Scientific Initiation