Guided endodontics: a comparative in vitro study on the accuracy and effort of two different planning workflows

Aim: To compare the accuracy and effort of digital workflow for guided endodontic access (GEA) procedures using two different software applications in 3D-printed teeth modeled to simulate pulp canal obliteration (PCO) in vitro. Materials and methods: 32 3D-printed incisors with simulated PCO were fabricated and mounted, four each on maxillary and mandibular study arches. Cone beam computed tomography (CBCT) and 3D surface scans were matched and used to virtually plan and prepare GEA by one operator using two different methods: 1) CoDiagnostiX (CDX; Dental Wings) with 3D-printed templates, and 2) Sicat Endo (SE; Sicat) with subtractive CAD/CAM-manufactured templates. Postoperative CBCT and virtual planning data were superimposed for analysis. Accuracy was assessed by measuring the discrepancies between planned and prepared cavities at the tip of the bur (three spatial dimensions, 3D vector, angle). Virtual planning effort was defined as the time and number of computer clicks. A 95% confidence interval (CI) was computed for each sample. Results: SE successfully located root canals for GEA in 16/16 cases (100%) and CDX in 15/16 cases (94%). SE resulted in less mean deviation at the tip of the bur with regard to distance in the labial-oral direction (0.12 mm), 3D vector (0.35 mm), and angle (0.68 degrees) compared with CDX (0.54 mm, 0.74 mm, 1.57 degrees, respectively; P 0.001). CDX required less mean planning time and effort for each four-tooth arch (10 min 50 s, 107 clicks) than SE (20 min 28 s, 341 clicks; P 0.05). Conclusions: Both methods enabled rapid drill path planning, a predictable GEA procedure, and the reliable location of root canals in teeth with PCO without perforation. Keywords: 3D printing, access cavity, accuracy, calcific metamorphosis, guided endodontics, pulp canal obliteration, root canal treatment, template