Antimicrobial efficacy of photodynamic therapy on dental implant surfaces: A systematic review of in vitro studies.

BACKGROUND: To systematically review the literature regarding the antimicrobial effects of photodynamic therapy (PDT) on multi-bacterial species and the possible surface alterations of dental implants as a result of PDT. METHODS: The addressed focused question was: "Does PDT show antimicrobial efficacy against multi-bacterial species colonization and result in surface alteration on dental implants?" Electronic databases including MEDLINE and EMBASE up to and including December 2018 were searched. RESULTS: Seven studies were included. Two studies used a total of 110 titanium dental implants, while 1 study included a total of 72 zirconia dental implants. Three studies investigated the antimicrobial PDT effects on titanium discs, while 1 study used titanium plates with germanium prisms. All in-vitro studies used diode laser. Energy fluence was reported only in 2 studies. Power output and density were 100 mW (mW) and 150 mW cm(-2), respectively. All in-vitro studies reported the multibacterial species outcomes after the application of antimicrobial PDT. All studies showed a significant reduction in the bacterial load. Only two studies reported the outcomes of microstructural changes on the titanium surface, in which both studies did not report any significant alterations on the titanium implants or discs with the application of PDT. CONCLUSION: This systematic review demonstrated significant reduction in the bacterial load but inconclusive findings regarding structural alterations on the titanium surface with the use of PDT. The results of this review should be considered preliminary and further in-vitro studies with standardized laser parameters are needed to obtain strong conclusions.