Comparative Evaluation of Remaining Pericervical Dentin Thickness after Instrumentation with Different Rotary File Systems with and Without Coronal Flaring Using CBCT: An in Vitro Study

Abstract

Introduction: Preservation of pericervical dentin (PCD) is a fundamental determinant of the biomechanical integrity and long-term prognosis of endodontically treated teeth. Excessive dentin removal during instrumentation, particularly in the cervical region, may predispose teeth to structural failure. Contemporary rotary systems are designed to optimize canal shaping while minimizing dentin loss; however, variations exist among different file systems and preparation techniques. Aim: This study aimed to evaluate and compare the remaining pericervical dentin thickness following instrumentation with different rotary file systems, with and without coronal flaring, using cone beam computed tomography (CBCT). Methods: Sixty extracted human mandibular first molars were selected and standardized. Samples were randomly divided into two groups: with coronal flaring and without coronal flaring (n = 30 each). Each group was further subdivided based on instrumentation system: TruNatomy, ProTaper Gold, and K3XF (n = 10 each). Pre- and post-instrumentation CBCT scans were obtained. Measurements of dentin thickness were recorded at 1 mm, 2 mm, 3 mm, and 4 mm below the furcation. Statistical analysis was performed using one-way ANOVA, Tukey post hoc tests, and independent t-tests. Study Design: In vitro comparative CBCT study. Results: TruNatomy consistently demonstrated the highest remaining dentin thickness at all levels, followed by K3XF and ProTaper Gold. Differences among file systems were statistically significant (p < 0.001). Coronal flaring resulted in slightly reduced dentin thickness; however, these differences were not statistically significant (p > 0.05). Conclusion: Rotary file design significantly influences pericervical dentin preservation. TruNatomy exhibited superior conservative shaping ability. Coronal flaring, when performed judiciously, does not significantly compromise dentin thickness.

Keywords: Pericervical dentin, Cone beam computed tomography, TruNatomy, ProTaper Gold, K3XF, minimally invasive endodontics, coronal flaring, rotary instrumentation