Fracture behaviors of monolithic lithium disilicate ceramic crowns with different thicknesses

Yu, Tao; Wang, Fu; Liu, Yan; Tao, Wu; Deng, Zaixi; Chen, Ji Hua

doi:10.1039/c6ra28847b

Cited by 15 publications

(19 citation statements)

References 39 publications

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“…Regarding the results of this research, all groups in this study showed a clinically acceptable marginal fit below 100 µm [10,11] The results proved that regardless the type of the milling device used, there was a significant increase in the marginal fit with 0.5 mm thickness laminate veneers in X5I, CMI and XLI subgroups. This finding was consistent with results showed by Yu et al [22], who concluded that the increased thickness of the ceramic can contribute to reducing the crack initiation within the ceramic and so increasing the marginal fracture resistance during milling. So, the first null hypothesis was rejected.…”

Section: Discussionsupporting

confidence: 93%

In vitro evaluation of marginal fit of zirconia-reinforced lithium silicate laminate veneers at two thicknesses using different CAD/CAM systems

El-Mahdy

Aboelfadl

Wahsh

2020

BDS

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Objective: The purpose of this in vitro study was to evaluate the marginal fit of laminate veneers made of zirconia-reinforced lithium silicate with two thicknesses using different CAD/CAM systems. Material and methods: 42 Laminate veneers milled from zirconia-reinforced lithium silicate were divided into three main groups according to milling machine used into: group X5, laminate veneers fabricated by inLab MCX5 milling machine; group CM, laminate veneers fabricated by Ceramill motion 2; and group XL, laminate veneers fabricated by inLab MCXL. Each group was divided into two subgroups according to veneer thickness into: subgroup I, 0.5 mm thickness laminate veneers and subgroup II, 0.3 mm thickness laminate veneers. The marginal fit was measured using stereomicroscope. The results were tabulated and statistically analyzed using two-way ANOVA test followed by Tukey’s post hoc test. Comparisons of main and simple effects were done utilizing Bonferroni correction (P ? 0.05). Results: The mean (±SD) highest marginal discrepancy was recorded in subgroup BII at 85.45±1.82 µm while the least mean marginal discrepancy was recorded in subgroup AI 71.24±2.64 µm. Conclusion: Both thicknesses (0.5 mm thickness and 0.3 mm thickness) and all tested CAD/CAM systems produced zirconia-reinforced lithium silicate laminate veneers with clinically acceptable marginal gaps; however, the closed CAD/CAM systems produced veneers with superior marginal fit than open systems at 0.3 mm thickness. The CAD/CAM system with the 5-axis milling machine produced the best marginal fit with 0.5 mm thickness. KEYWORDS Marginal fit; Zirconia-reinforced lithium silicate; Laminate veneers; CAD/CAM; Milling machines. RESUMOObjetivo: O objetivo deste estudo in vitro foi avaliar a adaptação marginal de facetas laminadas de silicato de lítio reforçado com zircônia com duas espessuras, utilizando diferentes sistemas CAD / CAM. Material e métodos: 42 facetas laminadas fresadas a partir de silicato de lítio reforçado com zircônia foram divididos em três grupos principais de acordo com a fresadora usada em: grupo X5, facetas laminadas fabricados pela fresadora inLab MCX5; grupo CM, facetas laminadas fabricados por Ceramill motion 2; e grupo XL, facetas laminadas fabricados pelo inLab MCXL. Cada grupo foi dividido em dois subgrupos, de acordo com a espessura do laminado, em: subgrupo I, facetas laminadas com 0,5 mm de espessura e subgrupo II, facetas laminadas com espessura de 0,3 mm. A adaptação marginal foi medida usando estereomicroscópio. Os resultados foram tabulados e analisados estatisticamente usando o teste ANOVA de dois fatores seguido pelo teste post hoc de Tukey. Comparações dos efeitos principais e simples foram realizadas utilizando a correção de Bonferroni (P ?0,05). Resultados: A maior discrepância marginal média (± DP) foi registrada no subgrupo BII em 85,45 ± 1,82 µm, enquanto a menor discrepância marginal média foi registrada no subgrupo AI 71,24 ± 2,64 µm. Conclusão: Ambas as espessuras (0,5 mm e 0,3 mm) e todos os sistemas CAD / CAM testados produziram facetas de laminado de silicato de lítio reforçadas com zircônia com lacunas clinicamente aceitáveis. No entanto, os sistemas CAD / CAM fechados produziam facetas com adaptação marginal superior aos sistemas abertos com 0,3 mm de espessura. O sistema CAD / CAM com a fresadora de 5 eixos produziu a melhor adaptação marginal com 0,5 mm de espessura.PALAVRAS-CHAVE Adaptação marginal; Silicato de lítio reforçado com zircônia; Facetas laminados; CAD / CAM; Fresadoras.

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Section: Discussionsupporting

confidence: 93%

In vitro evaluation of marginal fit of zirconia-reinforced lithium silicate laminate veneers at two thicknesses using different CAD/CAM systems

El-Mahdy

Aboelfadl

Wahsh

2020

BDS

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“…This difference in fracture pattern could be caused by the reduced thickness of ceramic at the load contact area and angulation of contact stresses inherent to the FE preparation 47 . This is supported by the results of an in vitro study that showed that the thickness of monolithic lithium disilicate ceramic crowns was responsible for such failures, and they recommended a minimum thickness of 1.0 to 1.2 mm 59 …”

Section: Discussionmentioning

confidence: 83%

Effect of incisal preparation design on load‐to‐failure of ceramic veneers

Bennani

Aarts

Lyons

et al. 2020

J Esthet Restor Dent

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Objective: This in vitro study aims to evaluate load-to-failure of ceramic veneers with butt joint (BJ) and feathered edge (FE) incisal preparation designs, and to correlate these results to the failure mode of the restorations. Materials and methods:One hundred and forty-eight typodont teeth (customized Nissin A25A-UL19B) were divided into two different preparation configurations BJ and FE and two different loading angulations, 0 and 20 . Lithium disilicate ceramic veneers (IPS e.max CAD, Ivoclar Vivadent) were milled using computer-aided-designand-computer-aided-manufacturing (CAD/CAM) techniques. Veneers were bonded to typodont teeth with resin cement (IPS Variolink Esthetic, Ivoclar Vivadent). Each group was loaded at the incisal edge using an Instron Universal Testing Machine at a crosshead speed of 0.01 mm/s till failure.Results: Pairwise comparison showed veneers from the BJ groups had a significantly higher load-to-failure value compared to the FE groups. Veneers with a FE preparation design loaded at 20 angulation had the lowest load-to-failure value.Conclusions: Within the limitations of the present study, both incisal preparation designs and loading angulations have significant effects on the load-to-failure values of ceramic veneers. BJ group exhibits a significantly higher load-to-failure value compared to the FE group.Clinical significance: BJ incisal preparation is preferred over FE preparation design. K E Y W O R D S butt joint, feathered edge, load-to-failure, preparation design, veneer preparation 1 | INTRODUCTION Ceramic veneers have become a popular treatment modality due to their conservative and esthetic nature and clinical performance. 1-3Compared to resin composite veneers, ceramic veneers are stronger and more durable, as they are less susceptible to wear, marginal fracture, discoloration, staining, and plaque accumulation. 4-6 A recent systematic review and meta-analysis of the clinical outcome of ceramic veneers showed that both feldspathic porcelain and glass-ceramic laminate veneers have high survival rates. 7 Glass-ceramic laminate veneers show a slightly higher survival rate than feldspathic porcelain veneers, 94% vs 87%, respectively. The complications reported were fracture/chipping (4%), debonding (2%), severe marginal discoloration (2%), endodontic problems (2%), and secondary caries (1%). 7 A recent retrospective clinical study conducted in a university setting by two academic staff with a follow-up of 20 years indicated that ceramic fracture was the main reason for failure of ceramic veneers. 1 This finding is also supported by numerous earlier clinical studies. 3,8-16

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“…The easy generation and propagation of radial cracks within thinner crowns cause catastrophic fractures, while the cone crack mechanism is predominantly observed in thicker crowns. 22 Harvey et al 23 suggested that the cone-crack fracture of glass-ceramic restorations requires a higher load leading to bulk fracture.…”

Section: Discussionmentioning

confidence: 99%

Effect of different preparation designs and all ceramic materials on fracture strength of molar endocrowns

Haralur

Alamrey

Alshehri

et al. 2020

Journal of Applied Biomaterials & Functional Materials

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Objective: The aim was to compare the fracture strength of Molar endocrowns fabricated from different all-ceramic materials and various preparation designs. Materials and methods: Ninety extracted human molar teeth were root canal treated and randomly divided into three groups according to the all ceramic materials used for fabrication of the endocrowns ( n = 30): (1) Lithium disilicate (IPS e.max Press); (2) Polymer infiltrated ceramic (Vita Enamic); (3) High translucency zirconia (Ceramill Zolid HT). Each group was subdivided into 3 subgroups ( n = 10) according to the preparation design as 2 mm occlusal reduction, 4.5 mm occlusal reduction, and 4.5 mm occlusal reduction with 2 mm radicular extension. The endocrowns from each material were fabricated and surface treated according to the manufacturer’s recommendations. After cementation with self-adhesive resin luting cement, the specimens were stored in a humid environment for 72 hours and subsequently subjected to 5000 thermal cycles. After, a compressive, static-axial load was applied using a universal testing machine until failure. Load-to-failure was recorded (N) and the specimens were examined under a stereomicroscope to determine the failure type. The data was statistically analyzed using One-way ANOVA and Tukey HSD tests at p < 0.05. Results: The Lithium Disilicate endocrowns recorded the higher mean fracture strength for 4.5 mm occlusal thickness and 2 mm radicular extension at 3770.28 N and 3877.40 correspondingly. The High translucency zirconia endocrowns at conventional 2 mm thickness showed the highest mean fracture load (3533.34 N). Even though polymer infiltrated ceramic endocrowns displayed comparatively lesser fracture load; they recorded the predominantly favorable fractures. Conclusions: Increased occlusal thickness showed a significant improvement in fracture strength of lithium disilicate and polymer infiltrated ceramic molar endocrowns. Although the 2 mm radicular extension had the substantial enhancement of fracture strength in high translucency zirconia, it resulted in more unfavorable failure types.

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Fracture behaviors of monolithic lithium disilicate ceramic crowns with different thicknesses

Cited by 15 publications

References 39 publications

In vitro evaluation of marginal fit of zirconia-reinforced lithium silicate laminate veneers at two thicknesses using different CAD/CAM systems

In vitro evaluation of marginal fit of zirconia-reinforced lithium silicate laminate veneers at two thicknesses using different CAD/CAM systems

Effect of incisal preparation design on load‐to‐failure of ceramic veneers

Effect of different preparation designs and all ceramic materials on fracture strength of molar endocrowns

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