Investigation of thermal stress in differentmetal-ceramic restorations by mathematicalanalysis

Abstract

Objectives: The aim of this study was to investigate the effect of heat changes in oralenvironment producing thermal stresses (TS) in prosthetic restorations by a mathematicalmethod.Material and Methods: Three different metals, commercial pure titanium (cpTi), preciousmetal alloy (Minigold, Bego dental, Bremen, Germany), chrome-cobalt-molybdenum (Wirobond,Bego dental, Bremen, Germany) were chosen for the frameworks. Titankeramik, VM13, andOmega 900 ceramics (Vita, Bad Sackingen, Germany) were used in theoretical analysis. Thephysical properties of the materials were obtained from manufacturers and from the literaturesreports. The calculation method was based on Boley’s equation.Results: In ceramics, the highest thermal stress was in titankeramik and the lowest was in VM13.Both commercial and theoretical samples were compared and at interface of the restoration,thermal stress accumulation was the highest in cpTi and titankeramik and the lowest was inprecious metal alloy and VM13 respectively. In metallic frameworks CrCoMo had the highestand semiprecious metal alloy had the lowest thermal stress deposition in its structures.Conclusions: Thermal stresses are not capable of breaking the metal-ceramic bond strength butshorten the life span of the prosthetics.