Methodologies used in quality assessment of root canal preparation techniques: Review of the literature

Objectives: To review the dentistry literature regarding methodologies and parameters used to evaluate the quality of performance of root canal debridement techniques and instruments. Methods: An extensive literature search with pre-defined inclusion and exclusion criteria was undertaken to identify studies that assessed root canal debridement, methodologies and parameters used to assess shaping and cleaning ability of root canal debridement and instruments. The relevant literature in the field of endodontics published from November 1950 to February 2014 was reviewed using PubMed and MEDLINE databases in all languages. Results: A large number of studies have assessed the quality of root canal instrumentation through the evaluation of cleaning ability (debris, smear layer) using histological sections and Scanning Electron Microscopy (SEM). The majority (71.9%) of studies evaluated the shaping ability. A body of literature has illustrated invitro applications of extracted teeth in muffle system and radiographic analysis. Additionally, the majority of studies have used Schneider angle technique as a random criterion. Micro-CT analysis has been increasingly used in the last decade. Conclusion: Several parameters are employed in the assessment of the post-operative shape or changes in the root canal morphology. Shaping ability of the root canal instrumentation techniques has been more extensively investigated than the cleaning ability. Additional care needs to be taken regarding entire angular changes by combining both Schneider and Canal Access Angel (CAA) methods and their variants. Finally, more concern regarding micro-computed tomography technique has been expressed.