An evidence-based evaluation of contemporary dental ceramics

The Effect of Clinical Sandblasting With Different Powders on the Surface Roughness of Cores for Metal-Ceramic Crowns and Their Fracture Resistance After the Addition of Repair Material: An In-Vitro Study

Background One of the most frequently encountered issues with metal-ceramic restorations is the fracture of veneering porcelain. This in-vitro study aims to evaluate the effect of clinical sandblasting with 50 μm aluminum oxide and 30 μm silica-coated particles on the surface roughness of metal cores and the subsequent effect on their fracture resistance after the addition of specific adhesive and packable composite as a repair material. Methodology Metal cores (n = 21) were digitally designed and three-dimensionally printed by selective laser melting (SLM) technique. These cores were randomly divided into three groups. Group A (n = 8) was sandblasted with 50 μm aluminum oxide and veneered with light cure composite. Group B (n = 8) was sandblasted with 30 μm silica-coated particles and veneered with light cure composite. Group C control group (n = 5) was sandblasted in the laboratory with 250 μm aluminum oxide and veneered with porcelain. All specimens were tested for surface roughness by a stylus profilometer. After adding the veneering material, all specimens were subjected to a fracture resistance test through a universal testing machine. Results One-way analysis of variance test showed a significantly higher difference for the specimens sandblasted in the laboratory using 250 μm aluminum oxide. Fracture resistance values showed no significant difference between groups A and B. Conclusions Groups A and B showed no significant difference in surface roughness, but their fracture resistance values were above the acceptable clinical limit. Despite the rough nature of metal cores fabricated by the SLM technique, sandblasting with silica-coated particles may be an effective way to optimize the fracture resistance of the repair material because it provides the basis for chemical adhesion.

Demystifying Modern Dental Ceramics

With increasing patient expectation for aesthetic dental restorations, there has been a drive towards developing ceramic materials to meet this expectation. Multiple ceramic systems have been introduced over the past four decades with considerable advances in material properties. Survival rates of all-ceramic crowns differ by type of ceramic used, fabrication method and clinical indication. Zirconia and lithium disilicate are the most commonly used contemporary ceramic materials in dentistry. Survival data for these types of restorations appears to be promising; however, there is a lack of high-quality long-term clinical data on the success of these restorations. In the absence of robust longitudinal clinical research, laboratory studies have provided some useful information on the performance of ceramic restorations. Further high quality long-term clinical studies are needed to inform us of modes of failure of these restorations and the range of clinical circumstances in which each type of ceramic restoration may be used.