title: Correlation between metal-ceramic bond strength and coefficient of linear thermal expansion difference.
abstract: The purpose of this study was to evaluate the metal-ceramic bond strength (MCBS) of 6 metal-ceramic pairs (2 Ni-Cr alloys and 1 Pd-Ag alloy with 2 dental ceramics) and correlate the MCBS values with the differences between the coefficients of linear thermal expansion (CTEs) of the metals and ceramics. Verabond (VB) Ni-Cr-Be alloy, Verabond II (VB2), Ni-Cr alloy, Pors-on 4 (P), Pd-Ag alloy, and IPS (I) and Duceram (D) ceramics were used for the MCBS test and dilatometric test. Forty-eight ceramic rings were built around metallic rods (3.0 mm in diameter and 70.0 mm in length) made from the evaluated alloys. The rods were subsequently embedded in gypsum cast in order to perform a tensile load test, which enabled calculating the CMBS. Five specimens (2.0 mm in diameter and 12.0 mm in length) of each material were made for the dilatometric test. The chromel-alumel thermocouple required for the test was welded into the metal test specimens and inserted into the ceramics. ANOVA and Tukey's test revealed significant differences (p=0.01) for the MCBS test results (MPa), with PI showing higher MCBS (67.72) than the other pairs, which did not present any significant differences. The CTE (10(-6) oC(-1)) differences were: VBI (0.54), VBD (1.33), VB2I (-0.14), VB2D (0.63), PI (1.84) and PD (2.62). Pearson's correlation test (r=0.17) was performed to evaluate of correlation between MCBS and CTE differences. Within the limitations of this study and based on the obtained results, there was no correlation between MCBS and CTE differences for the evaluated metal-ceramic pairs.
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Stella Crosara
authors.initials: SC
authors.lastname: Lopes
authors.forename: Valéria Oliveira
authors.initials: VO
authors.lastname: Pagnano
authors.forename: João Manuel Domingos de Almeida
authors.initials: JM
authors.lastname: Rollo
authors.forename: Mônica Barbosa
authors.initials: MB
authors.lastname: Leal
authors.forename: Osvaldo Luiz
authors.initials: OL
authors.lastname: Bezzon
mesh_terms: D055598:Chemical Phenomena; D003722:Dental Alloys; D001840:Dental Bonding; D003799:Dental Stress Analysis; D004055:Differential Thermal Analysis; D006358:Hot Temperature; D008422:Materials Testing; D016876:Metal Ceramic Alloys; D013718:Tensile Strength
chemical_list: D003722:Dental Alloys; D016876:Metal Ceramic Alloys