Accuracy of Static Guided Endodontic Access for Pulp Canal Obliteration: A Three-Dimensional Analysis of Sleeve Material and Height

Background Pulp canal obliteration (PCO) complicates endodontic access due to canal calcification and increases the risk of iatrogenic errors during conventional freehand procedures. Static guided endodontic access (SGEA) has been proposed as a minimally invasive solution; however, evidence regarding the influence of guide sleeve material and height on three-dimensional (3D) access accuracy is limited. This study aimed to evaluate the effect of sleeve material and height on the accuracy of SGEA in teeth with simulated PCO. Methods An in vitro experimental study was performed using forty-eight standardized replicas of maxillary central incisors with simulated PCO. Tooth-supported static guides were fabricated using sleeves of different materials: titanium (control), cobalt-chromium (CoCr), and zirconia with heights of 3, 5, and 7 mm. A freehand access group served as control. Pre- and post-operative cone-beam computed tomography (CBCT) datasets were superimposed to assess coronal (base) offset, apical (tip) offset, angular deviation, and access cavity volume. Data were analyzed using two-way ANOVA followed by Bonferroni post hoc tests (α = 0.05). Results Static guided access showed significantly lower coronal and apical deviations than freehand access, particularly in the labial and lingual directions (p < 0.001). Sleeve height significantly affected accuracy, with 7 mm sleeves demonstrating the lowest deviations and improved directional control. Zirconia sleeves, especially at 5–7 mm heights, exhibited superior accuracy and smaller access cavity volumes compared with metallic sleeves. Sleeve material had no significant effect on linear deviation, whereas sleeve height was a critical determinant of precision. Conclusions Three-dimensional analysis showed that static guided endodontic access produced lower base offset and tip offset than freehand access in teeth with simulated pulp canal obliteration, particularly in the labial–lingual direction (0.13 ± 0.19 mm and 0.10 ± 0.24 mm vs up to 2.23 ± 0.80 mm and 8.01 ± 0.70 mm). The lowest access cavity volume was observed with zirconia 5 mm sleeves (9.33 ± 1.90 mm³).