Performance of stereolithography and milling in fabricating monolithic zirconia crowns with different finish line designs

2021 ◽  
Vol 115 ◽  
pp. 104255
Author(s):  
Rong Li ◽  
Hu Chen ◽  
Yong Wang ◽  
Yuchun Sun
Keyword(s):  
Finish Line ◽  
Zirconia Crowns ◽  
Monolithic Zirconia

scholarly journals Effect of finish line design and cement space thickness on the marginal accuracy of monolithic zirconia crowns

2020 ◽  
Vol 23 (3) ◽  
Author(s):  
Mohamed Eldamaty ◽  
Mohammed Abdel-Aziz ◽  
Ahmed El-Kouedi ◽  
Tamer Hamza
Keyword(s):  
Space Thickness ◽  
Marginal Gap ◽  
Finish Line ◽  
Marginal Fit ◽  
Significance Level ◽  
Significant Difference ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
Line Design ◽  
Line Type

Objective: The purpose of this study was to evaluate the effect of finish line design and cement space thickness on the marginal accuracy of monolithic zirconia crowns. Materials and methods: Thirty crowns were fabricated from translucent zirconia (inCoris TZI) using Cerec in-Lab system and divided into three main groups (10 each) according to the finish line type of the die (knife-edge, chamfer, and shoulder). Every group was divided into two subgroups (5 each) according to cement space thickness (20 and50μm). Optical impressions were taken for the dies using the Cerec scanner and cement space was set twice for every finish line design; 20 and 50 μm. The completed crowns were cemented to the dies and the marginal gap was evaluated. The collected data was statistically analyzed using Mann-Whitney U test and Kruskal-Wallis test and the significance level was set at P ≤ 0.05. Results: Regarding the marginal gap; there was no statistically significant difference between different finish line designs or between different cement space thicknesses. Conclusion: Neither finish line design nor cement space thickness has an effect on the marginal gap of inCoris TZI crowns.KeywordsCement space; Finish line; Marginal fit; Monolithic zirconia.

scholarly journals Assessment of Tooth Preparations Submitted to Dental Laboratories for Fabrication of Monolithic Zirconia Crowns

2021 ◽  
Vol 9 (10) ◽  
pp. 112
Author(s):  
Ramtin Sadid-Zadeh ◽  
Hadjer Sahraoui ◽  
Brian Lawson ◽  
Robert Cox
Keyword(s):  
Three Dimensional ◽  
Finish Line ◽  
Posterior Teeth ◽  
3D Images ◽  
Line Angle ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
Tooth Preparation ◽  
Line Design

Purpose: The objective of this study was to assess the quality of posterior teeth prepared for monolithic zirconia crowns. Materials and Methods: A total of 392 STL-files of posterior preparations for monolithic zirconia crowns were evaluated in this study. Three-dimensional (3D) images were evaluated using a software (3D Viewer; 3Shape A/S, Copenhagen, Denmark) for finish line design, finish line width, occluso-cervical dimension, total occlusal convergence (TOC), intercuspal angulation, finish line quality, line angle form, and presence or absence of undercut at the axial wall and unsupported lip of enamel. The assessment was performed by two calibrated evaluators. Then, data were descriptively analyzed. Data for occluso-cervical dimension and TOC were descriptively analyzed according to their location. Results: Thirty-nine percent of premolars, 77% of first molars, and 91% of second molars had an average occluso-cervical dimension of less than 3 mm (premolars) and 4 mm (molars), with most of the preparations having a TOC of more than 20 degrees. More than 50% of preparations had undercut, unsupported enamel and/or unacceptable finish line quality. Conclusions: The quality of tooth preparation including finish line quality, absence of unsupported enamel and undercut at the axial wall should be evaluated when preparing monolithic zirconia crowns.

scholarly journals Quantitative analysis on the wear of monolithic zirconia crowns on antagonist teeth

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhenyu Tang ◽  
Xinyi Zhao ◽  
Hui Wang
Keyword(s):  
Epoxy Resin ◽  
Tetragonal Zirconia ◽  
Fatigue Wear ◽  
Posterior Teeth ◽  
Contact Points ◽  
Significant Difference ◽  
Zirconia Crowns ◽  
Natural Teeth ◽  
Monolithic Zirconia

Abstract Background The present study aimed to quantitate the wear of the highly transparent Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) ceramic monolithic zirconia crown on the enamel in vivo and discuss the prone position of the wear and the underlying mechanism. Methods A total of 43 patients with 43 posterior teeth were selected for full zirconia crown restoration and examined immediately, at 6 months, and at 1 year after restoration. During the follow-up visit, the fine impression of the patients’ monolithic zirconia crowns, the antagonist teeth, the corresponding contralateral natural teeth, the super plaster cast, and epoxy resin model was ontained. The model of epoxy resin was observed under a stereo microscope, and the microstructure parts were observed under a scanning electron microscope. Results After 1 year, the mean depth and volume of wearing of the monolithic zirconia crown were the smallest (all P < 0.01), while those of the antagonist teeth were significantly larger than those of the natural teeth (P < 0.0001), and no significant difference was found among the natural teeth (P = 0.3473, P = 0.6996). The amount of wear after one year was remarkably higher than that at 6 months (P < 0.0001). The microscopic observation revealed the tendency of wearing of the monolithic zirconia crown on the antagonist teeth at the protruding early contact points. Electron micrographs of tooth scars showed that the wearing mechanism of the monolithic zirconia crown on natural teeth was mainly abrasive and fatigue wear. Conclusions Although the self-wearing is insignificant, the monolithic zirconia crown can cause wear of the antagonist teeth via occlusal or early contact significantly; the amount of wearing is higher than that of natural teeth and increases over time. The wearing mechanism is mainly abrasive and fatigue wear.

scholarly journals Clinical evaluation of monolithic zirconia crowns: a failure analysis of clinically obtained cases from a 3.5-year study

2021 ◽  
Author(s):  
Shoko Miura ◽  
Shinobu Yamauchi ◽  
Shin Kasahara ◽  
Yusuke Katsuda ◽  
Masanori Fujisawa ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Clinical Evaluation ◽  
Zirconia Crowns ◽  
Monolithic Zirconia

scholarly journals Evaluation of marginal fit and microleakage of monolithic zirconia crowns cemented by bio-active and glass ionomer cements: In vitro study

2020 ◽  
Vol 23 (1) ◽  
Author(s):  
Radwa Hamdy Aboelenen ◽  
Ashraf Mokhtar ◽  
Hanaa Zaghloul
Keyword(s):  
Glass Ionomer Cement ◽  
Glass Ionomer ◽  
Marginal Gap ◽  
Marginal Fit ◽  
Group I ◽  
Significant Difference ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
Ionomer Cement ◽  
Gap Values

Objective: To evaluate the marginal fit and microleakage of monolithic zirconia crowns cemented with bioactive cement (Ceramir) compared to that cemented with glass ionomer cement and to evaluate the effect of thermocycling on marginal fit. Materials and methods: Twenty sound human molar teeth were prepared to receive a monolithic zirconia crowns. Teeth were divided randomly into two equal groups according to the type of luting cement. Group I: glass ionomer cement and group II: Ceramir cement. After cementation, the vertical marginal gap was assessed by using stereomicroscope before and after thermocycling. Twenty equidistant measurement points were taken for each crown. Leakage assessment was carried out using Fuchsin dye penetration followed by digital photography under a stereomicroscope. Data were analyzed by Mann-Whitney U test to compare between the two luting cements. Wilcoxon signed-rank test was used to evaluate the effect of thermocycling on the marginal fit (P ≤ 0.05)
Results: Whether before or after thermocycling, the results showed no significant difference between the marginal gap values of the two tested groups. For both groups, there was a significant increase in marginal gap values after thermocycling. Also, there was no significant difference between leakage scores of the two tested groups. Conclusions: Similarity in the physical properties and chemical composition of the two cements result in a non- significant effect on the vertical marginal fit and the extent of microleakage of translucent zirconia crowns.  Thermocycling had a negative impact on the vertical marginal gap of the two tested luting agents.

Sign in / Sign up

Export Citation Format

Share Document