The investigation of fracture strength of various temporary crown materials

Temporary crowns and bridges are fabricated to protect tooth preparations and adjacent gingiva until insertion of the final restoration, to restore normal tooth function, and thus to prevent occlusal changes and tooth migration. In the fixed prosthetic treatments, temporary crown and bridge materials must be strong, resistant to wear and fracture, as well as esthetics. In our study, polycarbonate crowns prefabricated by dental manufacturer and temporary acrylic and composite resin crowns fabricated in dental laboratory situations made from 6 materials were used. All temporary crowns were storaged in room temperature distilled water for 24 hours. Then, these crowns were seated on metal dies fabricated from Cr-Co alloy and they were tested by way of the indentor was located 1/3 inciso-palatinal surface and incisal edge with 135° using Hounsfield testing machine. The data were analyzed for differences by one-way ANOVA and Tukey's HSD test. Additionally, the types of failure obtained from the fracture strength test were observed under the steromicroscope. As a result of the each test, the crowns fabricated from Structur 2 Dominant resin material were demonstrated the minimum values, though the maximum values were obtained from polycarbonate crowns. However, temporary crowns used in our study were demonstrated lower values when the load were applied to incisal edge by the indentor directly.