Effect of Separated Instruments on Apical Seal of Root Canals Obturated with Different Techniques: An In-vitro Stereomicroscopic Study

Abstract

Introduction: Practitioners often encounter challenges during root canal preparation, particularly with instrument separation. There is a need to understand how broken instruments interact with different obturation techniques. Aim: To evaluate the extent of apical microleakage in root canals containing fractured instruments obturated using three different materials and techniques, and to investigate the interaction between fractured instruments and these obturation methods. Materials and Methods: This in-vitro study was conducted at Bharati Vidyapeeth Deemed to be University Dental College and Hospital, Pune, Pune, Maharashtra, India, over a duration of three months, from February 2024 to April 2024. Total 45 single-rooted premolars were decoronated and prepared with hand and rotary files upto size 20. A #25 rotary file was scratched and fractured 3 mm from the tip at the apex. Samples were randomly assigned to three obturation groups (n=15 each): Group A {Mineral Trioxide Aggregate (MTA)}, Group B (lateral compaction), and Group C (injectable gutta-percha). Roots were coated with nail varnish, sparing the apical 2 mm. The parameters studied included the degree of apical microleakage, which was measured by sectioning samples after 48 hours of immersion in methylene blue dye for observation under a stereomicroscope. Statistical analysis was performed using Statistical Package of Social Sciences (SPSS) version (IBM Corp, v.21.0). Intergroup comparison of apical microleakage (in mm) between different groups was conducted using One-way Analysis of Variance (ANOVA). Level of significance was set at p<0.05. Results: Intergroup comparison of apical microleakage (in mm) between different groups was performed using One-way ANOVA. This comparison showed statistically significant differences (p-value=0.047*) between the three groups. Pair-wise multiple Post-hoc comparison of apical microleakage (in mm) between different groups was performed using Tukey’s Post-hoc test. Group A (MTA) exhibited significantly lower microleakage (1.59 mm) compared to Group B (lateral compaction, 1.83 mm) and Group C (injectable gutta-percha, 2.25 mm). Groups A and B showed p-value of 0.047*, and Groups A and C showed p-value of 0.027*. No significant differences were found between Groups B and C (p=0.558). Conclusion: The MTA obturation demonstrated superior sealing capability compared to the other techniques, while comparable leakage was observed in the lateral compaction and injectable gutta-percha groups. These findings highlight the effectiveness of MTA in managing apical microleakage in the presence of fractured instruments.

Keywords

• dental instruments
• endodontics
• gutta-percha
• root canal filling materials