A Critical Review of Dental Lithia-Based Glass–Ceramics

Abstract

The purpose of this article is to review current understanding of lithia-based glass–ceramics and to identify future research needs for this class of dental materials in relation to novel compositions and fabrication methods. With rapid advances in material development and digital technology, time efficiency of dental workflow and fit accuracy of ceramic restorations are ever improving. Lithia-based glass–ceramics are at the forefront of this advance—new variants with more efficient fabrication routes are continually being introduced into the marketplace. Base glass composition, crystallization heat treatment, nucleant and coloration additives, and property gradation are some pertinent variables. The trend in fabrication is to move from CAD/CAM grinding of partially crystallized glass–ceramics to fully crystallized materials, thereby circumventing the need for postmachining firing altogether. In these endeavors, a better understanding of mechanical properties and evolving shaping technologies, such as ductile grinding, is paramount. Additive manufacturing and 3-dimensional printing methodologies offer a promising alternative to current CAD/CAM subtractive manufacturing routes. Challenges to the implementation of new technologies in efficient development and production of high-quality dental glass–ceramic prostheses are addressed.

Hydrofluoric acid concentration and etching time affect differently the microstructure and surface properties of pressed lithium disilicate glass ceramics

“…Although the aforementioned materials are lithium disilicates, different compositions and microstructures 7 could require different acid etching parameters to achieve adequate adhesive bonding. XRD analysis demonstrated similar crystalline phases for all the materials tested, however with different intensities, indicating a greater vitreous phase for LiSi Press.…”

“…Among these materials, silica/glass‐based ceramics have shown to provide excellent optical properties for esthetic treatments. However, silica/glass‐based ceramics are comprised by a high glass content (~40%–53%) 7 that reduces the material's strength 8 . To enhance the mechanical behavior of glass–ceramics, reinforcement crystals varying in size, shape and amount are frequently dispersed in the glassy matrix to provide a secondary phase 9 .…”

Influence of ceramic thickness and dental substrate on the survival rate and failure load of non‐retentive occlusal veneers after fatigue

“…[10][11][12] Compared to resin composites, glass ceramic materials offer a higher abrasion resistance, biocompatibility and color stability 13 eventually resulting in higher survival rate and lower risk of fracture. 14 Lithium disilicate (LDS) glass ceramic has shown to be a reliable material for the fabrication of minimally invasive restorations in terms of esthetic, mechanical properties 15 and clinical long-term survival. 16,17 Based on these in-vitro and clinical data, the manufacturer reduced the minimum occlusal layer thickness for adhesively bonded IPS e.max restorations to 1 mm.…”

Minimally invasive CAD/CAM lithium disilicate partial‐coverage restorations show superior in‐vitro fatigue performance than single crowns

“…In times of digital dentistry, the steadily evolving Computer‐Aided Design (CAD)/Computer‐Aided Manufacturing (CAM) technology leads to a trend toward monolithic restorations in all material classes 4–7 . Monolithic reconstructions fulfill the potential to avoid chipping and delamination problems, which are common in veneered bi‐layer systems, while reducing tooth substance removal and production costs at the same time 8–12 …”

“…[4][5][6][7] Monolithic reconstructions fulfill the potential to avoid chipping and delamination problems, which are common in veneered bi-layer systems, while reducing tooth substance removal and production costs at the same time. [8][9][10][11][12] Increased prevalence of severe tooth wear caused by biocorrosive defects, such as erosion, abrasion, attrition or combinations of these, especially in young patients, accelerated the development of minimally invasive treatment concepts. 13,14 To rehabilitate the posterior dentition in a minimal invasive approach, occlusal veneers evolved as the preferred treatment choice.…”