In vitro investigation of the breaking resistance of inley supported bridges produced by using monolithic zirconia materials in different brand and thickness

Agar B, An Evaluation of Fracture Resistance of Monolithic Inlay-Retained Zirconia Fixed Bridges Constructed with Different Brands and in Different Thicknesses in Vitro, Hacettepe University Graduate School of Health Sciences Prosthesis Program Dissertation, Ankara, 2018. Besides pathological situations such as decays, fractured teeth, trauma, periodontal diseases, internal and external resorptions, single tooth loss is a frequently seen result after unsuccessful endodontic and prosthetic applications. As an alternative to the traditional treatment methods, inlay-retained bridges have been commonly used after the advancements in full ceramic materials in recent years. In this study, the aim is to evaluate the fracture resistance of inlay-retained bridges which are produced with three different brands of monolithic zirconia material in accordance with two different connectors. A model which mimics the absence of mandibular first molar for cavity preparations was created in the study. 54 models were prepared with the impressions obtained with one stage impression technique by making use of A type silicone. For two different connector thicknesses, 9 inlay-retained bridge restoration were produced from Noritake KATANA, GC Initial Zirconia Disc and VITA YZ DISC HT monolithic Zirconia materials. Each restoration was cemented to their model with SDI set pp dual care resin luting cement in accordance with manufacturer's instructions. Samples were subjected to the fracture test crosshead speed as 1mm/min. in universal testing machine. As descriptive statics, mean, standard deviation, median, minimum and maximum value for numerical variables and number and percentage values for categorical variables were given. Two-way analysis of variance (two-way ANOVA) was used to compare groups and thicknesses in terms of depth. Paired comparison test was applied in case of any differences among groups. According to this, while fracture resistance impressions show significant difference (p<0,05) according to thickness groups, it does not show significant difference according to groups and thickness-group interaction (p>0,05). Average fracture resistance of those which had 3 mm thick connectors are significantly higher than the group that has 2 mm thick connectors.