Comparison of the Remaining Tooth Structure and Fracture Resistance between Labial and Lingual Access Cavities in Permanent Anterior Teeth with Labial Caries: An In-vitro Study

Statement of Problem: Labial access cavity preparation is a conventional method in endodontic treatment of the anterior teeth, but in some conditions labial cavity preparation is recommended.Purpose: The aim of this study was to compare labial and lingual access cavity preparation in the permanent anterior teeth with labial caries in terms of the remaining tooth structure and fracture resistance. Materials and Method: In this experimental study, 150 intact permanent human anterior teeth were selected in 5 groups each with 30 teeth including the maxillary central, maxillary lateral, maxillary canine, mandibular incisors and mandibular canine. A class V cavity with similar ratios to dimensions of each tooth was prepared on the labial surface of all specimens. The volumes of each of these teeth were measured by Penta Pycnometer before and after class V cavity preparation (V1, V2). Each group was randomly divided into 2 equal subgroups (n=15). Access cavities were prepared labially in subgroup A and lingually in subgroup B; then, the remained volume of each tooth was measured again (V3). The mean proportional volume loss of each tooth was calculated through access preparation (V2-V3/V1). Then, the specimens were embedded in acrylic resin blocks and subjected to load with a universal testing machine.Results: The differences of mean of theremained volume and fracture resistance of the two subgroups were statistically significant in all groups ( p <0.05) and those teeth with labial access showed more remained volume and fracture resistance than lingual access. Conclusion: Labial access cavity preparation can enhance the remained volume and fracture resistance as compared to lingual access in endodontic treatment of the anterior teeth with labial caries especially in mandibular incisors.