International Journal of Dental Sciences and Research, 2018, Vol. 6, No. 2, 25-28 Available online at http://pubs.sciepub.com/ijdsr/6/2/1 ©Science and Education Publishing DOI:10.12691/ijdsr-6-2-1 Anti-microbial Photo Dynamic Therapy (aPDT) in Endodontics: A Literature Review Muhammad Zubair Ahmad * Assistant Professor, Restorative Dental Sciences Department, Alrass Dental College, Qassim University, Buraydha, Saudi Arabia *Corresponding author: m.muhammad@qu.edu.sa Abstract Elimination of root canal pathogens is one of the main objectives for successful outcome of root canal treatment. Conventional chemo-mechanical debridement is not always successful in removing all bacteria. Adjunctive use of antimicrobial photodynamic therapy (aPDT) can be a used as a practical approach for successful elimination of all these bacteria. The aim of this review was to assess scientific literature that used various photosensitizers for bacterial reduction using aPDT methods. A search of the PubMed and Cochrane data bases using appropriate terms and keywords related to antimicrobial photodynamic therapy in endodontic disinfection was conducted. A hand search also was conducted in the preceding 5 years of several journals. Full texts of the selected articles were obtained and analyzed. A total of 177 articles published were identified at first stage of data extraction. After final screening, 41 articles were included in this review. This review summarizes the usage principles of aPDT and outlines the applications of aPDT in root canal disinfection procedures. It was concluded that aPDT should be used in conjunction with the conventional chemo mechanical debridement and disinfection of root canal system. It is critical to note that selection of photosensitizer dye, its correct delivery within the prepared root canal system, laser application with correct type of tips are predictors for successful outcome of this protocol of root canal disinfection. Keywords: Root canal disinfection, photodynamic therapy, E-faecalis Cite This Article: Muhammad Zubair Ahmad, “Anti-microbial Photo Dynamic Therapy (aPDT) in Endodontics: A Literature Review.” International Journal of Dental Sciences and Research, vol. 6, no. 2 (2018): 25-28. doi: 10.12691/ijdsr-6-2-1. 1. Introduction Endodontic treatment outcome is dependent on the presence and absence of microbes inside the root canal system [1]. Failure of root canal treatment is attributed to various causes from persistence of bacteria after treatment to micro leakage from coronal restorations in cases of late failures [2]. Variations and complexities of the root canal system, in addition to composition of dentin, are the main challenges to disinfect the root canal system [3]. There are different antimicrobials that are common in practice [4]; however, anatomical variations and un-instrumented areas of the canal can reduce their effectiveness considerably. To enhance the root canal disinfection properties of ordinary irrigants, using Anti-microbial photo dynamic therapy (aPDT) protocol is proposed. High power lasers due to their heat based destruction of microbes aided in developing the methods that are useful in root canals disinfection [5,6,7,8]. There are concerns of some undesirable effects on surface of radicular dentin that include carbonization and cratering with some lasers types e.g. Nd:YAG and carbon dioxide lasers, and this warrants following strict protocols to minimize these effects during use of these lasers for root canal disinfection [9]. 2. Search methodology and Study Selection A search was done of the PubMed and Cochrane databases using appropriate Medical Subject Headings terms and keywords related to use and application of aPDT in root canal disinfection. The following combination of MeSH terms and keywords were used: “anti-microbial photodynamic therapy” OR “photodynamic” OR “light activated disinfection” OR “photodynamic therapy” OR “photo-activated disinfection” AND “endodontics” OR “photodynamic therapy endodontics” OR “anti-microbial light activated disinfection root canal” OR “anti-microbial light activated disinfection endodontic” OR “photo-activated disinfection endodontics.” No time limit was applied. One hundred seventy-seven articles published were identified. After removal of duplication and full text screening of all the studies 41 articles were selected. From each study information was gathered for this review. 3. Disinfection by Photochemical Process A light of an appropriate wavelength is used to irradiate molecules of photosensitizer dyes, this promotes the target molecule to a high energy state also called triplet state that transfers its energy to oxygen molecule, which results in