Reinforced Glass-ceramics: Parametric Inspection of Three-Dimensional Wear and Volumetric Loss after Chewing Simulation

Abstract

The aim of this study was to investigate the three-dimensional wear, volumetric loss and surface roughness after chewing simulation of two glass ceramics. Lithium disilicate (LD, Emax CAD, Ivoclar) and Zirconia reinforced lithium silicate (ZLS, Vita Suprinity, Vita Zhanfabrick) discs (n=20/g) were scanned to obtain stereolithography (STL) files for each sample. All discs were submitted to chewing simulation with sliding configuration (30 N, 300,000 cycles, 6 mm and 1.7 Hz) with steatite as antagonist. The samples were then scanned again and the volume loss and the deepest defect depth was measured using the superimposed file from the baseline using three-dimensional digital parametric inspection software (GOM Inspect, Braunschweig, Germany). Surface roughness (Ra and Rz) was analyzed with a contact profilometer. Data were analyzed by one-way ANOVA and Tukey test (α=0.5%). ANOVA showed significant differences among the groups. Considering the ceramic volume loss, wear depth defect length and Rz roughness, LD (-22.09±5.57%; 0.80±0.06 µm; 3.08±1.02 µm) showed higher mean values than ZLS (-15.67±4.51%; 0.56±0.09 µm; 1.51±0.90 µm). Ra mean values were similar for both materials (p=0.064). All discs exhibited slight surface scratches along with the sliding direction with pitted wear patterns, while large cracks were observed on wear traces. These same areas can be identified in blue, overlapping the STL files before and after chewing simulation in inspection software. The linear reduction generated by sliding contact shows a graph with a similar wear pattern shape. ZLS was more resistant to wear than LD, with less volume loss and shallower surface defects.

Effect of defect size and tooth anatomy in the measurements of a 3D patient monitoring tool

“…It is important to consider the parameter used to display dental defects in the software [ 25 ]. In the software version used in the study, no distinction can be made between the reduction (negative) or gain (positive) in volume.…”

“…Another limitation is that the software only displays defects greater than 50 microns, as the minimum threshold established by the manufacturer. The averages tooth wear per year is 30 microns although the actual rate in the dental practice was expected to be higher [ 23 , 24 , 25 , 26 ]. Given the minimum 50 microns and the average yearly rate of tooth wear, the TPM could offer useful information in two years follow-up.…”

“…There are inherent study’s limitations that need to be taken into account before a clinical extrapolation. The in vitro environment simulated herein represents a different scenario than a clinical evaluation [ 25 , 26 , 27 , 28 ]. Additionally, to calculate the wear, only the highest value of each area was selected and not the total deviation.…”

Table-Top Lithium Disilicate Ceramic Restoration Thickness Effect on the Stress Distribution in Upper Premolars: 3D Finite Element Analysis

“…Among the available dental ceramics is glass ceramic reinforced with lithium disilicate crystals (approximately 60-70 %), guaranteeing a very translucent structure to this system while conferring a low refractive index that efficiently reflects light and still allows adequate mechanical resistance (Culp & McLaren, 2010;Matos et al;Tribst et al, 2021). In addition to offering a variety of colors and high flexural strength (360 to 400 MPa), this material is suitable for making restorations with minimum thicknesses which avoids excessive wear for the convenience of prosthetic preparations in the dental structure (Tribst et al, 2019(Tribst et al, , 2021. These characteristics confer versatility to the material enabling rehabilitation with single crowns in the posterior and anterior region through adhesive cementation.…”

Efeito da aplicação de líquidos para caracterização extrínseca do polimento e do glazeamento nas características superficiais propriedades ópticas e mecânicas da zircônia totalmente estabilizada na fase cúbica

“…Materiais com menores valores do módulo de elasticidade são responsáveis por promover menor concentração de estresse mecânico na superfície contra antagonistas de diferentes materiais restauradores em resposta às forças oclusais aplicadas em meio bucal (Tribst et al, 2019) A fase monoclínica contribui para o aumento da resistência do material (Prado et al, 2020). O mecanismo de transformação de fase monoclínica na zircônia totalmente estabilizada na fase cúbica decorre da pequena porcentagem de conteúdo na fase tetragonal presente no material (Dutra et al, 2017, Kolakarnprasert et al, 2019, Vila-Nova et al, 2020.…”