Reentry of endodontic access cavities: composite residue and loss of tooth substance

Abstract

The purpose of this study was to investigate the ability of dentists to remove composite fillings from endodontic access cavities using illumination from a conventional light source (CLS) versus the fluorescence-aided identification technique (FIT) in terms of completeness, selectivity and treatment duration. Therefore, two independent operators removed composite resin from six sets of root-filled incisors in a maxillary model under simulated clinical conditions using the CLS or FIT method (twelve teeth per operator and technique). The duration of treatment was recorded and before-after micro-CT scans were superimposed for volumetric assessment of treatment completeness and selectivity. Statistical significance was determined by t-testing and two-way ANOVA for operator comparison.
Overall, there was no significant difference be- tween FIT and CLS in terms of volume, height and area of composite residues (p = 0.98/p = 0.75/p = 0.64) and regarding hard tissue loss in terms of volume, depth and area (p = 0.93/p = 0.70/p = 0.14). However, there was a significant difference between the two groups regarding treatmenttime (FIT=428s, CLS=523s; p=0.023). Significant differences between operators regardless of method were found for volume, height and area of composite residues (p < 0.05) and also for defect area (p = 0.01) and time (p < 0.001). A significant difference between operators including the method was only found for height of composites (p = 0.037). It can be concluded, that composite remnants and tooth structure losses may occur after reentry of root-filled teeth regardless of the illumination method (conventional vs. fluorescence-aided) and operator, but preparation was less time-consuming with FIT.