In Vitro Comparative Analysis of Fracture Resistance of Lithium Disilicate Endocrown and Prefabricated Zirconium Crown in Pulpotomized Primary Molars

AIM: This study aimed to evaluate the effect of lithium disilicate endocrowns compared to prefabricated zirconia crown used for restoring pulpotomized primary molars, on their Fracture Resistance and to compare the loads to failure these different ceramic restorations with previously reported posterior occlusal forces. METHODS: Twenty mandibular left second primary molars were randomly distributed into two groups (n = 10 in each group) the zirconia Crown (Nusmile zr.) Group (G1) and the lithium disilicate (IPS e.max Press) Endocrown Group (G2). In all groups pulpotomy procedure was done before preparation then each sample was prepared based on their allocated restoration, both zirconia crown (Nusmile zr.) and endocrown (IPS e.max Press) were cemented by dual-cure resin cement. All samples were loaded to failure using a universal testing machine (Instron, USA), and the compressive force was applied. The data were analysed using one-way (ANOVA) and Tukey’s post hoc significance difference tests. Differences were considered significant at (p< 0.05). RESULTS: Group zirconia crown (G1) showed significantly higher fracture strength than Group (G2) lithium disilicate endocrown (p < 0.05). CONCLUSION: The zirconia crown showed higher fracture resistance than lithium disilicate endocrown. However, both tested zirconia crown and lithium disilicate endocrown withstood the application of axial occlusal forces greater than the reference values for posterior occlusal loads.