Speakers - 2026

Title: Does preheating resin cements affect fracture resistance of lithium disilicate and zirconia restorations

Abstract

Purpose:

The purpose of this study was to evaluate the effect of pre-heating of (adhesive and self-adhesive) resin cements on fracture resistance of lithium di silicate and tetragonal zirconia.

Materials and methods:

Eighty intact human maxillary premolars free of cracks and caries were prepared with a standard dimension and randomly divided into 2 main groups according to the material used for crowns fabrication (n=40)  as following: Group (Z): Monolithic zirconia (Blu-Zirkon; Simex Italia), Group (E): Lithium di silicate (IPS e.max PRESS; Ivoclar Vivadent). Each main group was subdivided into two equal subgroups according to type of resin cement: Subgroup (ZP): Blu Zirkon with Panavia SA cement plus, Subgroup (ZL): Blu-Zirkon with G C Link Force cement, Subgroup (EP): IPS e.max Press with Panavia SA cement plus, Subgroup (EL): IPS e.max Press with G C LinkForce cement. Half of the crowns were cemented by heated cement at 54C (h represents heated cement) and the other half were cemented by non heated cement stored at 25C (n represents non-heated cement). CAD/CAM crowns were fabricated from the material specified foe each main group. Resin cement tubes were heated for 24 hours at 54C by using BINDER incubator. Samples were exposed to thermo-cycling (10000 cycle between 5C and 55C) and cyclic loading (240,000 cycle). Fracture load was applied to all specimens under static compressive load using Instron Universal Testing Machine (Model 3345, Instron, Canton, MA. USA). The results were tabulated and statistical analysis was done with three way ANOVA method.

Results:

There was statistical significant difference between means fracture resistance of all ceramic crown materials (P<0.001). There was no statically significant difference between means fracture resistance of test groups of the same crown material with different resin cements (P>0.051). There was no statically significant difference between means of fracture resistance of test groups of the same crown material and the same cement with pre-heating of cement (P>0.283).