Fracture resistance of Y-TZP crowns fabricated with different cervical collars

• Grant number: 13/07404-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2013
• End date: September 30, 2014
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Marco Antonio Bottino
• Grantee: Tainá de Souza Rodrigues
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

The aim of this study is to evaluate the effect of partial or total removal of the cervical collar crowns with zirconia substructure on fracture resistance. From epoxy resin rods with 12 mm diameter will be machined 30 full crown preparations (central incisor). These preparations will be scanned and, from ceramic blocks based on zirconia (YZ Vita, Vita Zahnfabrik, Germany), it will be made 30 substructures. After sintering, these substructures will be scanned and the standard acrylic resin (CadWaxx, Vita Zahnfabrik, Germany) will be designed into the software system (InLab 3D, Sirona Dental Systems, Germany). This pattern attached to the substructure will be taken to a specific oven and the veneering ceramic (Vita PM9, Vita Zahnfabrik, Germany) will be injected. The crowns will be divided into 3 groups, varying the cervical collar of the substructure (SE): Gr1 - Collar total; Gr2 - Collar at 180; Gr3 - No cervical collar. The crowns will be cemented in preparations made in G10 resin (similar material to dentin) with dimensions similar to full crown preparations in anterior tooth. The specimens will be tested for resistance to fracture in Universal Testing Machine (EMIC, Brazil) with a load cell of 1000 Kgf and constant speed of 1mm/min. The data will be analyzed by analysis of variance (ANOVA) and differences by Tukey test with significance 95%. (AU)