Survival rates of teeth treated with bacterial photo-dynamic therapy during disinfection of the root canal system

Objective To ascertain the survival of teeth having undergone root canal therapy, when bacterial photo-dynamic therapy (bacterial PDT) was used as an adjunct during root canal system disinfection. Design Retrospective survival analysis (Kaplan-Meier method) of endodontically-treated teeth, when bacterial PDT was used as an adjunct during root canal system disinfection by a single operator in a private general dental practice. Materials and methods The records relating to endodontically treated teeth, performed between 27 May 2001 and 23 June 2016, were sourced. The details of these were placed into a database that permitted flexible interrogation. Survival data on de novo root canal treated teeth (RCT), and those requiring revision of the endodontic treatment (reRCT), were exported into a statistical package to permit survival analysis by the method of Kaplan-Meier. Results The number of teeth available for analysis were RCT = 620 and reRCT = 167. Percentage survival at two, four, six, eight, and ten years for RCT was 98.31, 97.38, 95.76, 91.81 and 91.80 respectively. When non-endodontic failures were excluded percentage survival was 99.27, 98.91, 98.28, 97.33 and 97.33 respectively. Percentage survival of teeth having undergone reRCT at the same time periods was 94.14, 92.77, 86.52, 84.09 and 84.09 respectively and respectively. When non-endodontic failures were excluded percentage survival was 96.01,96.01,93.67,63.67 and 93.67 respectively. Conclusions Within the limitations of the study, the survival rates of teeth treated with bacterial PDT, as an adjunct during root canal system disinfection, compare very favourably with previously published work where bacterial PDT was not used. The effectiveness of conventional chemo-mechanical disinfection of the root canal system may be enhanced by the adjunctive use of bacterial PDT, particularly in reRCT cases.