Resistance to Fracture of Lithium Disilicate Feldspathic Restorations Manufactured Using a CAD/CAM System and Crystallized with Different Thermal Units and Programs.

Cristian Abad-Coronel,Benjamín José Martín Biedma,Jorge I Fajardo,Andrea Ordoñez Balladares

doi:10.3390/ma14123215

Abstract

The aim of this study was to determine the resistance to fracture of feldspathic restorations with lithium disilicate and crystallized with different ovens and programs. Methods: Sixty monolithic restorations (LD) (EMAX CAD™ LT, Ivoclar-Vivadent™) were designed with the same parameters and milled with a CAD/CAM system (CEREC SW 5.1, CEREC MCXL, Dentsply-Sirona™, Bensheim). Each restoration was randomly assigned by randomization software (RANDNUM) to one of the three groups: (a) (NF) Oven P310 (Ivoclar, Vivadent) normal crystallization program, (b) (FF) Ivoclar P310 oven (Ivoclar-Vivadent™) rapid crystallization program, or (c) (SF) SpeedFire oven (Dentsply-Sirona™). Results: There were statistically significant differences between the groups (ANOVA, p < 0.05). The NF and FF groups showed the highest values of resistance to fracture, with statistically significant differences with the SF group. Conclusions: Using a furnace from the same dental company with predetermined programs from the material manufacturer, as well as using a predetermined program for rapid crystallization, has no effect on fracture resistance, and would save clinical time when performing ceramic restorations with lithium disilicate, while keeping their mechanical properties.

Highlights

Ceramic CAD/CAM blocks were introduced to the dental market in 1980 [1]
One of the CAD/CAM materials most used for indirect restorations is feldspathic ceramic with lithium disilicate crystals, EMAX-CADTM (Ivoclar-VivadentTM, Liechtenstein), which was developed in 2005, and which in its pre-crystallized or metasilicate intermediate state shows a purple color due to the stains used to identify this state
A statistically significant difference was not found between the Normal Firing (NF) and Fast Firing (FF) groups (p = 0.537) (Figure 4)

Summary

Introduction

Ceramic CAD/CAM blocks were introduced to the dental market in 1980 [1]. One of the CAD/CAM materials most used for indirect restorations is feldspathic ceramic with lithium disilicate crystals, EMAX-CADTM (Ivoclar-VivadentTM, Liechtenstein), which was developed in 2005, and which in its pre-crystallized or metasilicate intermediate state shows a purple color due to the stains used to identify this state. This material in the metasilicate state requires a certain time and temperature to reach its crystallized final state. The appropriate combination is usually between 800 ◦ C and 870 ◦ C, for 5 to 30 min

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Discussion

Conclusion