Impact of conservative endodontic access cavity on the biomechanical behavior of maxillary premolars with non-carious cervical lesions restored with different materials

• Grant number: 22/14927-8
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2023
• End date: August 31, 2025
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Fabiane Carneiro Lopes Olhê
• Grantee: Fabiane Carneiro Lopes Olhê
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated researchers: Jardel Francisco Mazzi Chaves ; Manoel Damiao de Sousa Neto

Abstract

The purpose of this study will be to evaluate the impact of conservative endodontic access cavity on the fracture resistance and failure pattern of maxillary premolars with wedge-shaped non-carious cervical lesions (NCCL) restored with different materials. One hundred maxillary premolars will be selected and distributed according to the endodontic access cavity: control (healthy) (n=10), control with NCCL (n=10), NCNC with conventional endodontic cavity (CC) (n=40) and NCCL with conservative endodontic cavity (CEC) (n=40). Wedge-shaped NCCLs will be prepared in the vestibular region. The CC and CEC will be performed using 1014 HL and Endo Z drills and E7D ultrasonic tip. The canals will be prepared with Reciproc Blue system following the manufacturer's guidelines. The specimens will be filled with epoxy resin based sealer using the single cone technique, and restored with temporary material. After the biomechanical preparation and filling, a new randomization will be performed according to the restorative material (n=10): control (provisional restorative material), conventional composite resin, regular bulk fill composite resin and fluid bulk fill composite resin associated with conventional composite resin. After 7 days, the teeth will be restored according to respective groups using conventional composite resin through the incremental technique, regular bulk fill composite resin in a single increment and a single increment of fluid bulk fill composite resin with a layer of conventional composite resin. The samples will be subjected to thermocycling and cyclic loading. A compressive 45o load will be applied in the palatal plane of the buccal cusp until the tooth fracture. Fracture strength and failure patterns will be analyzed using analysis of variance and chi-square test (±=0.05), respectively. Also, 1 healthy maxillary premolar, 1 with NCCL, and 1 of each type of access (conventional and conservative) representative of the evaluated teeth will be selected, which will be scanned in a micro-CT and reconstructed. Three-dimensional models of the teeth with the endodontic access conditions and the restorative materials will be generated for analysis by the finite element method. (AU)