LAUSR

AIM To evaluate 3D accuracy and outcome of a dynamic navigation method for guided root canal treatment of severe pulp canal obliteration (PCO) in 3D printed jaws. METHODOLOGY Three operators with different levels of experience in Endodontics performed navigated access cavities, using the Navident system (ClaroNav, Toronto, Canada), in 2 sets (maxillary and mandibular) of 3D-printed jaw models with teeth presenting severe PCO. Models were mounted on a phantom to mimic a real clinical situation. After treatment, a post-operative high resolution CBCT scan (NewTom, Verona, Italy) was taken for each model and registered to the pre-operative model. All access cavities were then segmented using 3-Matic Medical software 15.0 (Materialise, Leuven, Belgium). Length and volume of each access cavity was measured, and a comparison was done by measuring the distance deviation in mm at the coronal entry point, apical point, vertical deviation, total deviation and angular deviation of the access cavity in comparison to the virtual planning. Additionally, all access cavities were scouted with a size 10 K-file and inspected on the CBCT to confirm that the canal was located. Descriptive statistics for each parameter were performed. Normality of the data was assessed; data were transformed if needed to make it normally distributed. One-way Analysis of Variance (ANOVA) was applied to assess differences between parameters for tooth type, jaw, and operators and corrected for simultaneous hypothesis testing according to Tukey. Significance level was set at 0.05. RESULTS After training with the system (28 cavities per operator), a total of 132 teeth and 168 access cavities (56 per operator) were prepared. All operators found a total of 156 canals, obtaining an overall success of 93% without difference between operator experience (p > 0.05). The mean deviation at the apical point was 0.63 mm (SD 0.35) and was significantly lower in anterior teeth in comparison to molars (p < 0.05). The mean angular deviation from the planning was 2.81° (SD 1.53). CONCLUSION Dynamic navigation was an accurate approach for root canal treatment in teeth with severely calcified canals. However, the technique has a learning curve and requires extensive training prior to its use clinically.