Influence of the location of the deep margin elevation in the biomechanical behavior and marginal quality of endodontically treated central incisors

• Grant number: 21/09713-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: January 01, 2023
• End date: July 01, 2026
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Guilherme de Siqueira Ferreira Anzaloni Saavedra
• Grantee: Elisa Donária Aboucauch Grassi
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil
• Associated scholarship(s): 23/11332-6 - Effect of various surface modifications on the bonding strength of composite to an IDS layer and to contaminated dentin and performance of laminated ceramic veneers with immediate dentin sealing: follow up 15-year clinical study, BE.EP.DR

Abstract

This study aims to evaluate the stress distribution, fatigue behavior and marginal quality of endodontically treated incisors, without ferrule and with glass fiber post, restored with composite resin crowns, varying the presence and location of deep margin elevation (DME). Consisting of a 2x3 factorial design, considering the factors presence of DME in 2 levels (with [E], and without [SE]), and location in 3 levels (mesial proximal surface [P], vestibular [V], and lingual [L]). 138 bovine roots will be used for the fatigue test (n=13), and for the marginal infiltration test (n=10). The number of cycles and the load at which each specimen fail will be used for Kaplan-Meier and Mantel-Cox (Log Rank test) statistical analysis (± = 5%). The failure will be evaluated by stereomicroscopy. For the marginal quality test, thermocycling (6,000 cycles from 5 to 55ºC) and mechanical cycling (100N /100,000 cycles) will be performed. After cycling, the specimens will be immersed in a coloring substance for 24 hours, sectioned, to assess marginal infiltration under stereomicroscopy. The stress distribution will be assessed by finite element analysis. For this, the groups will be reproduced in 3D (three-dimensional) digital models. The models will be considered isotropic, linearly elastic and homogeneous, except for the glass fiber post that will be considered orthotropic. An axial load (100 N) will be applied at the cingulum (30°). The stress distribution in the restorations, adhesive interfaces and the dental structure will be analyzed by the Maximum Principal Stress criteria. The results discussed before the relevant literature.