Comparative Cone Beam Computed Tomographic Evaluation of Conventional and Conservative Endodontic Access Cavity Designs on Pericervical Dentin Thickness and Fracture Resistance of Teeth: An In-vitro Study

Introduction: The concept of ‘extension for prevention’ accelerates treatment processes but eliminates precious dentin at the pericervical area, resulting in biomechanically weakened tooth structure after endodontic treatment. Pericervical Dentin (PCD) is a new paradigm for endodontic success supports the idea that the amount of residual tooth structure is closely associated with long-term retention of the tooth and resistance to fracturing.

Aim: To determine the impact of two endodontic access cavity designs and biomechanical preparation on the pericervical dentin thickness using three-dimensional (3D) Cone Beam Computed Tomographic (CBCT) visualisation technique and fracture resistance of the maxillary anterior teeth under compressive load using universal testing machine.

Materials and Methods: The in-vitro study was conducted in the Department of Conservative Dentistry and Endodontics at Karnavati School of Dentistry, Karnavati University, Gandhinagar, Gujarat, India, from October 2020 to March 2021. Study was carried out on the 30 single rooted freshly extracted maxillary central incisors and were randomly divided into two groups of conventional and conservative access preparation groups (n=15). Group 1 was conventional group, samples were accessed using endo access bur #1. Group 2 was conservative group, samples were accessed using CK micro-endodontic bur under a dental operating microscope. Cleaning and shaping was done using 17% Ethylenediamine Tetraacetic Acid (EDTA) as lubricant and 4% Hyflex CM rotary file system. The CBCT scans were taken preoperatively, following access cavity preparation and post obturation to evaluate the amount of pericervical dentin loss in mesial, lingual, facial and distal surfaces of the teeth at the levels of 1 mm to 4 mm above and below Cementoenamel Junction (CEJ). The samples were then loaded to fracture in the Universal Testing Machine, and the data were analysed using Independent sample t test using Statistical Package for Social Sciences (SPSS) software version 20.0.

Results: In comparison to the group 2, group 1 led to an increase in substantial tooth structure loss in the pericervical region. Among all surfaces, pericervical dentin loss was more pronounced on the lingual surface in the group 1 than in the group 2 (p-value <0.001). Higher fracture resistance was observed in group 2 (1136.75 N) compared to group 1 (687.22 N) under compressive load (p-value <0.001).

Conclusion: Incisal cavity design is a less invasive method of accessing maxillary central incisors that preserves pericervical dentin. Under compressive load, pericervical dentin conservation provided greater fracture resistance in the conservative group than in the conventional group.