Influence of convergence angle of tooth preparation on the fracture resistance of Y-TZP-based all-ceramic restorations

• Grant number: 10/15009-5
• Support Opportunities: Regular Research Grants
• Start date: December 01, 2010
• End date: November 30, 2012
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Alvaro Della Bona
• Grantee: Alvaro Della Bona
• Host Institution: Faculdade de Odontologia (FOSJC). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil
• Associated researchers: Pedro Henrique Corazza

Abstract

The aim of the study is to investigate the influence of the convergence angle of the tooth preparation and the wear of the burs used in a CAD-CAM system on the fracture strength (Ã) of Y-TZP-based all-ceramic restorations veneered by a feldspathic ceramic. The microstructure of the ceramics (In-Ceram YZ e Vita VM9) will be characterized using scanning electron microscopy (SEM) and EDS. Young's modulus, Poisson's ratio, density, hardness and fracture toughness will be also evaluated. Finite element analyzes (FEA) in dimensionally identical models to the ones used in vitro will be performed to verify the stress distribution. One hundred In-Ceram YZ (Vita) substructures will be fabricated by the Cerec inLab CAD-CAM system and divided into three groups according to the axial convergence angle: G1 - 6° (n=20), G2 - 12° (n=60) e G3 - 20° (n=20). The substructures will be veneered with a feldspathic ceramic (Vita VM9). The wear of the burs from the CAD-CAM system will be recorded after machining each substructure. The influence of the wear of the burs on the à of the restorations will be evaluated relating the surface roughness, the wear of the burs and the à values of each substructure machined in G2. The restorations will be cemented on an epoxy resin die and submitted to compressive loading until fracture. Half of the specimens of each group will be cyclic fatigued (one million cycles) before the à test. Fracture surfaces will be examined following the fractography principles and the à data will be statistically analyzed using ANOVA and Tukey tests, at significance level of 5%. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

CORAZZA, PEDRO HENRIQUE; FEITOSA, SABRINA ALVES; SOUTO BORGES, ALEXANDRE LUIZ; DELLA BONA, ALVARO. Influence of convergence angle of tooth preparation on the fracture resistance of Y-TZP-based all-ceramic restorations. Dental Materials, v. 29, n. 3, p. 339-347, MAR 2013. (10/15009-5)

CORAZZA, PEDRO HENRIQUE; DE CASTRO, HUMBERTO LAGO; FEITOSA, SABRINA ALVES; KIMPARA, ESTEVAO TOMOMITSU; DELLA BONA, ALVARO. Influence of CAD-CAM diamond bur deterioration on surface roughness and maximum failure load of Y-TZP-based restorations. AMERICAN JOURNAL OF DENTISTRY, v. 28, n. 2, p. 95-99, APR 2015. (10/15009-5)