Shrinkage‐Free, Alumina–Glass Dental Composites via Aluminum Oxidation

Abstract

Alumina–glass composites that contain oxidized aluminum were investigated to make shrinkage‐free, all‐ceramic dental porcelain. This was achieved by control of the volume expansion and shrinkage that occur during the aluminum oxidation and densification processes. The dimensional change and strength of the alumina‐glass composites were dependent on the aluminum content and particle size. A shrinkage‐free sample with a strength of 330 MPa and transmittance of 1.21 was fabricated by using 4‐5 vol% of aluminum powder with an average particle size of 6 μ m in the alumina‐glass composite made by the In‐Ceram method.

Evaluation of glass viscosity of dental bioceramics by the SciGlass information system

“…The compositions of the glasses used in glass-infiltrated ceramic composites reported in literature [34][35][36][37] are shown in Table 3, and are divided in two groups according to the type of porous ceramic preform used for glass infiltration: aluminaAl 2 O 3 (A1 to A3), or spinel-MgAl 2 O 4 (S1 to S5). The reported infiltration temperatures are also indicated in Table 3.…”

“…Viscosity determines the temperatures at which the processing Table 3 Compositions (mol%) of glasses used for infiltration of porous preform of alumina -Al 2 O 3 (A1 to A3) and spinel -MgAl 2 O 4 (S1 to S5), and respective temperature of infiltration (T), from literature [34][35][36][37]. techniques of glasses will occur, like melting, forming, annealing, thermal tempering, and ion-exchange [38,39].…”

Systematic approach to preparing ceramic–glass composites with high translucency for dental restorations

“…1 shows the calculated viscosities from the chemistry of some glasses as a function of the temperature used for the infiltration process reported in Refs. [15][16][17]. It could be observed that the viscosities of the glasses at the infiltration temperature ranged from around 10 2 to 10 3 dPa s. Therefore, in this work it was established that the glass should have viscosity lower than 10 2 dPa s at 1200 • C for the design of glass composition.…”

Influence of Multi-cycle Infiltration on Porosity and Optical Properties of Glassinfiltrated Alumina Biocomposites for Dental Restorations

“…Light scattering significantly decreases total light transmittance through the material [8]. In addition, residual porosity significantly reduces the mechanical properties of the biocomposite, [5] and is considered the most significant optical heterogeneity in its microstructure, causing significant light scattering and therefore decreasing light transmittance [8].…”

“…Good aesthetics for artificial teeth can be obtained using glass-infiltrated alumina biocomposites, which can be translucent enough to mimic the characteristics of the natural teeth, [3] yet keeping an excellent, accurate marginal and internal adaptation after multiple heat treatments [4]. The good marginal adaption of these glass-infiltrated alumina biocomposites is related to the low shrinkage of the final material, [5] which is below 0.5%, due to the fact that pre-sintering of the preform and infiltration of the glass are performed at relatively low temperatures [6].…”