Rapid method for the detection of root canal bacteria in endodontic therapy.

INTRODUCTION: Complete eradication of microorganisms is essential for successful root canal therapy. However, current methods to evaluate persistent bacteria after therapy are not widely practiced. Adenosine triphosphate (ATP) is an indicator of viable cells. The bioluminescence-based ATP assay is easy to perform, and results can be obtained in a clinically relevant time frame of 5 minutes. The aims of this study were to evaluate the sensitivity of the ATP detection method and the specificity of this assay for viable cells and to compare the ATP and culture methods from root canal samples of patients undergoing endodontic treatment. METHODS: The sensitivity of the ATP assay was determined using bacterial species commonly isolated from root canals. Bacteria were treated with sodium hypochlorite; after which, culture plating and the ATP assay were performed. Forty-three root canal samples before (S1) and after (S2) instrumentation and 36 samples after the removal of calcium hydroxide dressing (S3) were collected from patients undergoing root canal treatment and subjected to ATP assay and anaerobic culture. RESULTS: The sensitivity of the ATP assay was determined to be between 10 and 100 bacterial cells. This method of detection also correlated well with the presence of viable bacteria. The ATP readings obtained allowed clear segregation of anaerobic culture-positive and -negative samples obtained from infected root canals of patients. CONCLUSIONS: The ATP detection method can be used as a rapid tool to determine the presence of viable bacteria during root canal therapy. This method may be potentially useful as an adjunct to root canal treatment.