How effective is CBCT-guided endodontic access over 'brain-guided' accesses, and is this a likely addition to the...

Non-randomised prospective single-arm controlled clinical trial. The main inclusion criteria for both guided and freehand access groups was pulp canal obliteration (PCO). All teeth underwent cone-beam CT (CBCT) scan prior to access. Null hypothesis was that there is no difference in technical failure between guided and unguided access. The primary outcome was canal location success as a discrete measure (found, not found, perforated). The secondary outcome was conservativeness of drill pathway using discrete measures (optimal precision, acceptable precision, technical failure (included canal not found and perforation)). Patients underwent one subsequent annual follow-up.

Patients attended for consultation at one centre (University Hospital Leuven, Belgium). PCO extent was assigned using periapical radiograph followed by CBCT. Cases graded as 'high difficulty' (via qualitative assessment) by briefed endodontists within the centre were selected for the study. Control group was taken from historical records as assigning an active patient to the freehand over the guided group was considered unethical.

Sample size calculation to achieve conventional 80% power and statistical significance of 0.05% was undertaken, mandating 60 teeth per group. An analysis including all data, without matching, was performed by a generalized linear model for binary data using a logit link function with the primary outcome (canal found or not found/perforation) as response variable and the technique (guided or freehanded) as explanatory variable. p  ≤  0.05 was considered statistically significant. Blinding of operators was not possible. Teeth were matched (paired) per group to achieve group homogeneity.

Guided access yielded a 98.3% (n = 59/60) success rate with only one case unsuccessful (canal not found). In comparison, freehand access yielded 81% (n = 59/73) success rate, with 9.5% (n = 7/73) of teeth with canals unfound, and 9.5% (n = 7/73) of teeth perforated. Null hypothesis rejected given statistical significance of results (p = 0.011).

Cases presenting with PCO that undergo guided access show optimal outcomes both from an endodontic and from a conservational perspective, with significant increased chances of canal location in a conservative manner. Freehand correction in guided access cases can be used to inform changes to initial guided access if the canal is not found.