Effect of total occlusal convergence on fit and fracture resistance of zirconia-reinforced lithium silicate crowns

Alammari, Manal R; Abdelnabi, Mohamed H.; Swelem, Amal A.

doi:10.2147/ccide.s193326

Cited by 11 publications

(18 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…When using natural teeth, the researcher can perform various bonding techniques that have a significant influence on the behavior of the materials being investigated. 37,38 In in-vitro studies, the dentin wetness, thickness and the pressure of the tooth pulp are influential variables that try to imitate in-vivo conditions. The modulus of elasticity of natural teeth is essential factor when applying fracture tests as the other materials do not behave as natural teeth.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of zirconia and zirconia‐reinforced glass ceramic systems fabricated for minimal invasive preparations using a novel standardization method

Kasem

Sakrana

Ellayeh

et al. 2020

J Esthet Restor Dent

View full text Add to dashboard Cite

Objective: Currently, minimal invasive approaches combining less invasive finish line preparations and reduced ceramic thickness are required. The aim of this study was to evaluate the fracture resistance of two ceramic systems fabricated with two preparation designs using CAD/CAM standardization technology. Materials and methods: Forty intact human maxillary premolars were divided into two main groups according to the preparation technique. Group H (Horizontal): teeth with shoulder finish line and group V (Vertical): teeth with feather edge. Each main group was subdivided randomly into two subgroups according to the material used. Group CD (Celtra Duo) zirconia-reinforced glass ceramics and group K (KATANA) monolithic zirconia. CAD/CAM was used for standardization of natural teeth preparation. After cementation using self-adhesive resin cement, all specimens were subjected to 5000 thermal cycles and then were loaded until fracture. Failure types were evaluated using Stereomicroscopy and Scanning Electron Microscopy (SEM). Results: Nonsignificant; the higher mean value was recorded with VCD group (482.5 ± 103.8 N) and VK group (1347.6 ± 177.4 N) vs HCD group (471 ± 107.6 N) and HK group (1255.6 ± 121.3 N). SEM findings showed that fractures occurred mainly at the occlusal side of the crowns. Conclusions: Vertical preparation showed a promising alternative to horizontal preparation. Moreover, both Celtra Duo and KATANA crowns can be used in premolar area with 0.5 mm margin thickness. Clinical significance: Zirconia-reinforced glass ceramic and monolithic zirconia crowns may not necessitate the preparation of invasive finish lines as the type of finish line did not impair the strength after aging conditions

show abstract

Section: Discussionmentioning

confidence: 99%

Evaluation of zirconia and zirconia‐reinforced glass ceramic systems fabricated for minimal invasive preparations using a novel standardization method

Kasem

Sakrana

Ellayeh

et al. 2020

J Esthet Restor Dent

View full text Add to dashboard Cite

show abstract

“…A total of 32 crowns were thus fabricated for marginal and internal fit evaluation: Group 1, 16 monolithic Zi crowns; Group 2, 16 monolithic ZLS crowns (n = 16). The sample size of this study was based on earlier related published studies [ 25 , 28 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. Based on the mean differences and standard deviation assumptions, the total sample size was estimated as 24 crown samples (12 for each of the two ‘ceramic material’ groups), at α = 0.05 and power of 85% (G* Power statistical power software v.3.1.9.7) for the marginal and internal gap evaluations.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of Marginal/Internal Fit and Fracture Load of Monolithic Zirconia and Zirconia Lithium Silicate (ZLS) CAD/CAM Crown Systems

2021

View full text Add to dashboard Cite

Fit accuracy and fracture strength of milled monolithic zirconia (Zi) and zirconia-reinforced lithium silicate (ZLS) crowns are important parameters determining the success of these restorations. This study aimed to evaluate and compare the marginal and internal fit of monolithic Zi and ZLS crowns, along with the fracture load, with and without mechanical aging. Thirty-two stone dies acquired from a customized master metal molar die were scanned, and ceramic crowns (16 Zi Ceramill Zolid HT+ and 16 ZLS Vita Suprinity) were designed and milled. Absolute marginal discrepancies (AMD), marginal gaps (MG), and internal gaps (IG) of the crowns, in relation to the master metal die, were evaluated using x-ray nanotomography (n = 16). Next, thirty-two metal dies were fabricated based on the master metal die, and crowns (16 Zi; 16 ZLS) cemented and divided into four groups of eight each; eight Zi with mechanical aging (MA), eight Zi without mechanical aging (WMA), eight ZLS (MA), and eight ZLS (WMA). Two groups of crowns (Zi-MA; ZLS-MA) were subjected to 500,000 mechanical cycles (200 ± 50 N, 10 Hz) followed by axial compressive strength testing of all crowns, until failure, and the values were recorded. Independent sample t tests (α = 0.05) revealed no significant differences between Zi and ZLS crowns (p > 0.05); for both internal and marginal gaps, however, there were significant differences in AMD (p < 0.005). Independent samples Mann–Whitney U and Kruskal–Wallis tests revealed significant differences between the two materials, Zi and ZLS, regardless of fatigue loading, and for the individual material groups based on aging (α = 0.05). Multiple comparisons using Bonferroni post-hoc analysis showed significant differences between Zi and ZLS material groups, with or without aging. Within the limitations of this study, the ZLS crown fit was found to be on par with Zi, except for the AMD parameter. As regards fracture resistance, both materials survived the normal range of masticatory forces, but the Zi crowns demonstrated greater resistance to fracture. The monolithic Zi and ZLS crowns seem suitable for clinical application, based on the fit and fracture strength values obtained.

show abstract

“…The results hence rejected the hypothesis described in the introduction. Alammari et al [34] reported that an increase of TOC (from 12 to 20 degree) did not affect marginal and internal fit but resulted in higher load to fracture values of ceramic crowns. A similar finding was reported by Corazza et al [35], who compared the influence of 6 • , 12 • , and 20 • TOC on the fracture load of yttria partially stabilized zirconia veneered with feldspathic porcelain.…”

Section: Discussionmentioning

confidence: 99%

Fracture Resistance of Monolithic Zirconia Crowns on Four Occlusal Convergent Abutments in Implant Prosthesis

et al. 2019

View full text Add to dashboard Cite

Featured Application: Thicker and appropriately designed monolithic zirconia crown in the posterior implant area may have better fracture resistance even if the abutment needs to be milled to a convergent occlusal surface for a new insertion pathway.Abstract: Adjusting implant abutment for crown delivery is a common practice during implant installation. The purpose of this study was to compare the fracture resistance and stress distribution of zirconia specimens on four occlusal surface areas of implant abutment. Four implant abutment designs [occlusal surface area (SA) SA100, SA75, SA50, and SA25] with 15 zirconia prostheses over the molar area per group were prepared for cyclic loading with 5 Hz, 300 N in a servo-hydraulic testing machine until fracture or automatic stoppage after 30,000 counts. The minimum occlusal thickness of all specimens was 0.5 mm. Four finite element models were simulated under vertical or oblique 10-degree loading to analyze the stress distribution and peak value of zirconia specimens. Data were statistically analyzed, and fracture patterns were observed under a scanning electron microscope. Cyclic loading tests revealed that specimen breakage had moderately strong correlation with the abutment occlusal area (r = 0.475). Specimen breakage differed significantly among the four groups (P = 0.001). The lowest von Mises stress value was measured for prosthesis with a smallest abutment occlusal surface area (SA25) and the thickest zirconia crown. Thicker zirconia specimens (SA25) had higher fracture resistance and lowest stress values under 300 N loading.

show abstract

Effect of total occlusal convergence on fit and fracture resistance of zirconia-reinforced lithium silicate crowns

Cited by 11 publications

References 43 publications

Evaluation of zirconia and zirconia‐reinforced glass ceramic systems fabricated for minimal invasive preparations using a novel standardization method

Evaluation of zirconia and zirconia‐reinforced glass ceramic systems fabricated for minimal invasive preparations using a novel standardization method

Evaluation of Marginal/Internal Fit and Fracture Load of Monolithic Zirconia and Zirconia Lithium Silicate (ZLS) CAD/CAM Crown Systems

Fracture Resistance of Monolithic Zirconia Crowns on Four Occlusal Convergent Abutments in Implant Prosthesis

Contact Info

Product

Resources

About