Influence of root canals flattening degree on endodontic treatment and restorative procedure with fiberglass post

• Grant number: 18/12694-0
• Support Opportunities: Regular Research Grants
• Start date: October 01, 2018
• End date: March 31, 2021
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Yara Teresinha Correa Silva Sousa
• Grantee: Yara Teresinha Correa Silva Sousa
• Host Institution: Universidade de Ribeirão Preto (UNAERP). Campus Ribeirão Preto. Ribeirão Preto , SP, Brazil

Abstract

The aim of this study will be to evaluate, by means of microCT, the anatomy of mandibular molars and the influence of root canal flattening degree on the endodontic treatment and the restorative procedure with different fiberglass posts methods. Four hundred mandibular molars will be scanned with microCT for two-dimensional (area, perimeter, circularity, larger diameter, smaller diameter and shape factor) and three-dimensional (volume, surface area and SMI) root canal data record. Two hundred and four distal roots with different flat root canal will be selected for this study. For the first study, 144 roots will be assigned into two groups according to the flattening degree (n=72): oval shape and flat shape canals. Each group will be subdivided into two groups according the biomechanical preparation (n=36): TRUShape system and Reciproc Blue system. The roots will be rescanned with microCT to evaluate the two and three-dimensional data changes according to the biomechanical preparation system used. The root canals will be assigned into three groups according the filling technique: Lateral Compaction, Tagger's Hybrid Technique and Single Cone. The roots will be rescanned with microCT to evaluate the voids volume percentage after filling. The roots will be sectioned into 2 mm thick slices. The first slice from each root third will be used for push out test with a universal testing machine at 0.5 mm/min to evaluate the filling material bond strength to root dentin, and the second slice from each root third analyzed with scanning electron microscopy (SEM) to evaluate the filling material/root dentin bonding interface. For the restorative analysis, 60 roots will be assigned into two groups according to the flattening degree (n=30): oval shape and flat shape canals. The roots will be prepared with TRUShape system and filled with AH Plus sealer and gutta-percha cones by lateral compaction technique. The root post space will be prepared with no 1 to 3 Largo drills with 4 mm of root filling remaining. The roots will be rescanned with microCT and assigned to three groups according to the root canal post (n=10): Resin post reinforced with fiber glass; Bundled glass fiber-reinforced composite post; two previous techniques combined. The luting process will be performed with a universal adhesive system and a dual-curing adhesive system. The roots will be scanned with microCT to evaluate the posts fitting to the root canal and luting composite volume measure. The roots will be sectioned into 2 mm thick slices. The first slice from each root third will be used for push out test with a universal testing machine at 0.5 mm/min to evaluate the material bond strength to root dentin. The three-dimensional finite element analysis will be used to evaluate the tension created between the different post methods and flattened and oval shape root canals. All data will be submitted to statistical analysis. (AU)