2D radiographs, cone-beam computed tomography and 3D CBCT-based planning software in access cavity preparation: A single blinded randomised controlled in vitro study.

This study compared endodontic access cavities prepared by operators of different experience levels (students, general-practitioners and specialists), guided by periapical radiographs, cone-beam computed tomography (CBCT) or 3D CBCT-based planning software, with regards to tooth substance loss and preparation errors. Operators (n = 34) prepared endodontic access cavities in 306 three-dimensionally printed copies of human teeth with standardised anatomies. Access cavities were volumetrically assessed post-operative using digital scans, while preparation errors were evaluated with CBCT. Tooth substance loss was significantly influenced by the operator's experience, being highest with students', followed by general-practitioners and specialists (P < 0.05), with no significant association with the employed imaging/planning modality. Pulp chamber floor, iatrogenic perforations and incomplete pulpal roof removal were insignificant between operator groups or imaging/planning modalities. It can be concluded that irrespective of advancement in imaging/planning modalities the practitioner's experience level remains to be the decisive factor significantly influencing tooth substance loss during endodontic access cavity preparations.