Influence of different surface treatments on the fracture toughness of a commercial ZTA dental ceramic

Flavio Teixeira Da Silva,Helio Salim De Amorim,Marcio Alessandro Negrelly Zacché

doi:10.1590/s1516-14392007000100014

Flavio Teixeira Da Silva, Helio Salim De Amorim + Show 1 more

Open Access

https://doi.org/10.1590/s1516-14392007000100014

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Abstract

The objective of this study was to investigate how mechanical surface treatments performed for removal of excess of molten glass, influence the fracture toughness of a dental zirconia toughened alumina (In-Ceram® Zirconia). Infiltrated ZTA disks were submitted to three different surface treatments (grinding, sandblasting and grinding + sandblasting + annealing). Fracture toughness was accessed through indentation strength test (IS). X ray diffraction was used to investigate the metastability of tetragonal zirconia particles under all treatments proposed. Kruskall-Wallis non-parametrical test and Weibull statistics were used to analyze the results. Grinding (group 1) introduced defects which decreased the fracture toughness and reliability, presenting the lowest KIC. On the other hand, grinding followed by sandblasting and annealing (group 3) presented the highest KIC. Sandblasting (group 2) presented the highest reliability but lower KIC compared to group 3.

Highlights

The loss or destruction of teeth due to periodontal disease, caries or trauma, have lead dentistry and engineering professionals to develop new materials and search for prosthetic treatments for the replacement of those missing teeth.Until recently, all ceramic restorations were indicated only for single crowns and partial coverage restorations due to their low flexural strength and fracture toughness.Many all ceramic systems were developed with the goal to improve the possible indications of metal free restorations
In terms of tetragonal/monoclinic zirconia content, it can be seen that tetragonal zirconia is the predominant phase
It is clear that tetragonal zirconia content increased after sintering (1180 °C), which is an evidence that the starting powder was originally milled

Summary

Introduction

The loss or destruction of teeth due to periodontal disease, caries or trauma, have lead dentistry and engineering professionals to develop new materials and search for prosthetic treatments for the replacement of those missing teeth.Until recently, all ceramic restorations were indicated only for single crowns and partial coverage restorations due to their low flexural strength and fracture toughness.Many all ceramic systems were developed with the goal to improve the possible indications of metal free restorations. The loss or destruction of teeth due to periodontal disease, caries or trauma, have lead dentistry and engineering professionals to develop new materials and search for prosthetic treatments for the replacement of those missing teeth. All ceramic restorations were indicated only for single crowns and partial coverage restorations due to their low flexural strength and fracture toughness. Many all ceramic systems were developed with the goal to improve the possible indications of metal free restorations. The In-Ceram® Zirconia (Vita Zahnfabrik, Bäd Sackingen – Germany) is composed of α-alumina with 33 w% partially stabilized zirconia (12 mol% Ceria), partially sintered in two steps at low temperature (1120 and 1180 °C) to avoid shrinkage, followed by glass infiltration at 1140 °C, resulting in a dense and high strength ceramic core material, mainly used for replacing posterior teeth with all ceramic restorations. The processing steps are similar to the well known In-Ceram® Alumina technique[1]

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