scholarly journals Wear Behavior of Monolithic Zirconia against Natural Teeth in Comparison to Two Glass Ceramics with two Surface Finishing Protocols: An In-Vitro Study

2020 ◽  
Vol 23 (2) ◽  
Author(s):  
Dina Kamal Abouelenien ◽  
Hany Halim Nasr ◽  
Hanaa Zaghloul
Keyword(s):  
Weight Loss ◽  
Surface Finish ◽  
Glass Ceramic ◽  
Wear Behavior ◽  
Ceramic Materials ◽  
Surface Finishing ◽  
Group I ◽  
Significant Difference ◽  
Monolithic Zirconia ◽  
Natural Tooth

Objective: To evaluate and compare the wear behavior of three different ceramic systems; monolithic zirconia, lithium di-silicate and nano-fluorapatite glass ceramic with two finishing procedures polishing and glazing, and their effect on the wear of natural tooth antagonists. Material and Methods: Forty two ceramic disc specimens (10mm x3mm) and forty two natural tooth antagonists were used. Samples were divided according to ceramic materials into 3 groups (n = 14). Group I: nano-fluorapatite glass ceramic (FLU) (IPS e.max Ceram), Group II: lithium disilicate (LD) (IPS e.max CAD) and group III: monolithic zirconia (ZIR) (ZirkoZahn Prettau). Each group was further subdivided into two subgroups (n = 7), according to the surface finish: Polishing (P) and glazing (G). Specimens were subjected to a custom designed two-body wear simulator. Quantitative wear assessment was carried out using weight loss measurements. Scanning electron microscope was used for characterization of wear patterns. Kruscal Wallis and Dunn’s tests were used to compare between weight loss of the three ceramic materials. Whitney U test was used to compare the weight loss between the two surface finish protocols. Wilcoxon Signed rank test was used to compare the weight loss between ceramic specimens and antagonist teeth (p ≤ 0.05). Paired t-test was used to compare weight loss before and after wear test. Results: After wear, LD and FLU had the highest weight loss values compared to ZIR (p < 0.05). For teeth, there was no significant difference between the weight loss values with the three materials (p > 0.05). P and G specimens showed no significant difference in weight loss values. SEM images of the wear patterns verified the previous analysis. Conclusion: ZIR is more wear resistant than LD and FLU. However, the surface treatment had no impact on the wear behavior.KEYWORDSGlass-ceramics; Monolithic; Two-body wear simulation; Wear; Zirconia.

Factors Affecting the Wear Behavior of Monolithic Zirconia and the Antagonists: Literature Review

2020 ◽  
Vol 2 (1) ◽  
pp. 4-11
Author(s):  
Marcia Borba ◽  
Paula Benetti ◽  
Giordana P. Furini ◽  
Kátia R. Weber ◽  
Tábata M. da Silva
Keyword(s):  
Literature Review ◽  
Glass Ceramic ◽  
Wear Behavior ◽  
Glass Ceramics ◽  
Surface Treatments ◽  
Human Tooth ◽  
Initial Surface ◽  
Monolithic Zirconia ◽  
Feldspathic Porcelain

Background: The use of zirconia-based ceramics to produce monolithic restorations has increased due to improvements in the optical properties of the materials. Traditionally, zirconiabased ceramics were veneered with porcelain or glass-ceramic and were not directly exposed to the oral environment. Therefore, there are several doubts regarding the wear of the monolithic zirconia restoration and their antagonists. Additionally, different surface treatments are recommended to promote a smooth surface, including glaze and several polishing protocols. To support the correct clinical application, it is important to understand the advantages and limitations of each surface treatment. Objective: The aim of this short literature review is to investigate the factors that may affect the wear of monolithic zirconia restorations in service and their antagonists. Methods: Pubmed/Medline database was accessed to review the literature from a 10-year period using the keywords: zirconia, monolithic, prosthesis, wear. Both clinical and in vitro studies were included in the review. Results: Studies investigated the effect of several surface treatments, including grinding with diamond- burs, polishing and glazing, on the surface roughness, phase transformation and wear capacity of monolithic zirconia. The wear behavior of monolithic zirconia was frequently compared to the wear behavior of other ceramics, such as feldspathic porcelain, lithium disilicate-based glassceramic and leucite-reinforced glass-ceramic. Human tooth, ceramics and resin composites were used as antagonist in the investigations. Only short-term clinical studies are available (up to 2 years). Conclusion: Literature findings suggest that zirconia monolithic restorations are wear resistant and unlikely to cause excessive wear to the antagonist, especially when compared to feldspathic porcelain and glass-ceramics. Monolithic zirconia should be polished rather than glazed. Yet, none of the polishing systems studied was able to completely restore the initial surface conditions of zirconia after being adjusted with burs. More clinical evidence of the antagonist tooth wear potential of monolithic zirconia is needed.

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.

scholarly journals Wear of Ceramics Systems with Different Surface Applications in a Chewing Simulator

2020 ◽  
Vol 7 (10) ◽  
pp. 670-679
Author(s):  
Mehmet Çağatay Ulucan ◽  
Giray Bolayır ◽  
Ayşegül Saygın ◽  
Koray Soygun
Keyword(s):  
Weight Loss ◽  
Dental Materials ◽  
Surface Treatments ◽  
Highest Weight ◽  
Significant Difference ◽  
Before And After ◽  
Optical Profilometer ◽  
Substance Loss ◽  
Monolithic Zirconia ◽  
Chewing Simulator

Objective:   This study was aimed to compare the wear of four types of the ceramic dental materials with different surface treatments. Material and Methods: Porcelain (low-fusing feldspathic, monolithic zirconia, lithium disilicate glass, and leucite glass-ceramic) samples (9 x 3 mm) were prepared with different surface treatments (glazed and mechanical polished). Samples were mechanically loaded in a chewing simulator (600.000 cyles of 50N) and 64 teeth were used to simulate as the antagonist. To evaluate the wear of the samples before and after the test, samples were scanned by 3D scanner, Dental Wings 7 Series. Then they were transformed into the digital platform. Surface analysis was performed by using an optical profilometer and scanning electron microscope. A sensitive digital scale was used for weight measurements of antagonist's teeth. Results: It was a significant difference between the volume values of the groups with mechanical polish and the groups with glaze, except for zirconia samples (p<0.05). While the least change in volume and surface roughness was observed in the zirconia mechanic polished group (ZP), this change was not statistically significant (p>0.05). In terms of the weight measurement results of the antagonist teeth, while  leucite reinforced overglazed group (PRG) has the highest weight loss as a result of wear, ZP group has the least weight loss. Conclusion: It was concluded that glazed groups of ceramics lose more substances than polished groups, and that causes more wear on antagonist teeth. Zirconia ceramics showed less substance loss, and that causes less wear on antagonist teeth.

scholarly journals Effectiveness of a custom-made natural tooth powder on oral hygiene status of children: A randomized controlled trial

2020 ◽  
Vol 5 (4) ◽  
pp. 125-129
Author(s):  
Sharath Asokan ◽  
◽  
Geetha Priya PR ◽  
Sudhandra Viswanath ◽  
B Kesavaraj ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Streptococcus Mutans ◽  
Oral Hygiene ◽  
Antioxidant Properties ◽  
Diffusion Method ◽  
Group I ◽  
Custom Made ◽  
Significant Difference ◽  
Group Ii ◽  
Natural Tooth

Aim: To evaluate antibacterial, antifungal, antioxidant properties of custom-made natural tooth powder and the effectiveness of custom-made natural tooth powder on the oral hygiene status of children. Methodology: Antibacterial and antifungal properties were determined by agar diffusion method against Streptococcus mutans, Candida albicans and antioxidant properties were determined by DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assay. Clinical trial included 60 children aged 8 to 11 years. Oral prophylaxis was done and after a washout period of 10 days, baseline Simplified Oral Hygiene index (OHI-S) scores, plaque scores and Streptococcus mutans colony counts were recorded. Children were randomly divided into two groups: Group I children brushed with custom-made natural tooth powder and Group II children used commercially available natural tooth powder twice daily. At the end of 30 days, post intervention data was collected and statistically analyzed. Results: In-vitro trial showed that the custom-made natural tooth powder exhibited both antimicrobial and antioxidant properties. Intragroup assessment of clinical trial showed significant reduction in the OHI-S [Group I (p=0.03), Group II (p=0.01)] plaque scores [Group I (p=0.05), Group II (p=0.006)] and Streptococcus colony counts [Group I (p=0.000), Group II (p=0.000)] in both the groups. But there was no statistically significant difference between the two groups. Conclusion: The newer custom-made natural tooth powder is effective in oral hygiene maintenance and can be a possible alternative to the commercially available natural tooth powder.

Influence of Ceramic Thickness and Ceramic Materials on Fracture Resistance of Posterior Partial Coverage Restorations

2015 ◽  
Vol 40 (2) ◽  
pp. 211-217 ◽  
Author(s):  
EM Bakeman ◽  
N Rego ◽  
Y Chaiyabutr ◽  
JC Kois
Keyword(s):  
Glass Ceramic ◽  
Fracture Resistance ◽  
Testing Machine ◽  
Lithium Disilicate ◽  
Ceramic Materials ◽  
Tooth Structure ◽  
Partial Coverage ◽  
Significant Difference ◽  
Ceramic Thickness ◽  
Ceramic Restorations

SUMMARY This study evaluated the influence of ceramic thickness and ceramic materials on fracture resistance of posterior partial coverage ceramic restorations. Forty extracted molars were allocated into four groups (n=10) to test for two variables: 1) the thickness of ceramic (1 mm or 2 mm) and 2) the ceramic materials (a lithium disilicate glass-ceramic [IPS e.max] or leucite-reinforced glass ceramic [IPS Empress]). All ceramic restorations were luted with resin cement (Variolink II) on the prepared teeth. These luted specimens were loaded to failure in a universal testing machine, in the compression mode, with a crosshead speed of 1.0 mm/min. The data were analyzed using two-way analysis of variance and the Tukey Honestly Significantly Different multiple comparison test (α =0.05). The fracture resistance revealed a significant effect for materials (p&lt;0.001); however, the thickness of ceramic was not significant (p=0.074), and the interaction between the thickness of ceramic and the materials was not significant (p=0.406). Mean (standard deviation) fracture resistance values were as follows: a 2-mm thickness of a lithium disilicate bonded to tooth structure (2505 [401] N) revealed a significantly higher fracture resistance than did a 1-mm thickness of leucite-reinforced (1569 [452] N) and a 2-mm thickness of leucite-reinforced ceramic bonded to tooth structure (1716 [436] N) (p&lt;0.05). There was no significant difference in fracture resistance values between a lithium disilicate ceramic at 1-mm thickness (2105 [567] N) and at 2-mm thickness. Using a lithium disilicate glass ceramic for partial coverage restoration significantly improved fracture resistance compared to using a leucite-reinforced glass ceramic. The thickness of ceramic had no significant effect on fracture resistance when the ceramics were bonded to the underlying tooth structure.

scholarly journals Fracture Strength of Zirconia and Alumina Ceramic Crowns Supported by Implants

2015 ◽  
Vol 41 (S1) ◽  
pp. 352-359 ◽  
Author(s):  
Tonino Traini ◽  
Roberto Sorrentino ◽  
Enrico Gherlone ◽  
Federico Perfetti ◽  
Patrizio Bollero ◽  
...  
Keyword(s):  
Fracture Strength ◽  
Glass Ceramic ◽  
Ceramic Materials ◽  
Fracture Load ◽  
Fractographic Analysis ◽  
Core Material ◽  
Loading Test ◽  
Significant Difference ◽  
Cad Cam ◽  
Ceramic Crowns

Due to the brittleness and limited tensile strength of the veneering glass-ceramic materials, the methods that combine strong core material (as zirconia or alumina) are still under debate. The present study aims to evaluate the fracture strength and the mechanism of failure through fractographic analysis of single all-ceramic crowns supported by implants. Forty premolar cores were fabricated with CAD/CAM technology using alumina (n = 20) and zirconia (n = 20). The specimens were veneered with glass-ceramic, cemented on titanium abutments, and subjected to loading test until fracture. SEM fractographic analysis was also performed. The fracture load was 1165 (±509) N for alumina and 1638 (±662) N for zirconia with a statistically significant difference between the two groups (P = 0.026). Fractographic analysis of alumina-glass-ceramic crowns, showed the presence of catastrophic cracks through the entire thickness of the alumina core; for the zirconia-glass-ceramic crowns, the cracks involved mainly the thickness of the ceramic veneering layer. The sandblast procedure of the zirconia core influenced crack path deflection. Few samples (n = 3) showed limited microcracks of the zirconia core. Zirconia showed a significantly higher fracture strength value in implant-supported restorations, indicating the role played by the high resistant cores for premolar crowns.

scholarly journals Clinical Evaluation of Wear Behavior of Human Enamel and Chipping of Veneered Zirconia against Monolithic Zirconia (Randomized Controlled Clinical Trial)

2020 ◽  
Vol 23 (4) ◽  
pp. 11p
Author(s):  
Nouran Mahmoud Ibrahim ◽  
Reham El-basty ◽  
Hesham Katamish
Keyword(s):  
Wear Behavior ◽  
Intervention Group ◽  
United States Public Health ◽  
Controlled Clinical Trial ◽  
Full Coverage ◽  
Human Enamel ◽  
Significant Difference ◽  
Monolithic Zirconia ◽  
Group 2 ◽  
Group 1

Objective: To evaluate the wear behavior of human enamel and chipping of veneered and monolithic zirconia for posterior full coverage restorations. Material and methods: Thirty-four zirconia full coverage restorations (seventeen in each group) were fabricated. The patients were divided into two groups according to the type of zirconia used; group 1 (comparator group) veneered zirconia crowns and group 2 (intervention group) monolithic zirconia single crowns. All crowns were lab fabricated and polished. For opposing teeth wear measurements 3D non-contact profilometer was used where epoxy resin replicas were constructed for opposing arch immediately after crowns cementation, three, six and twelve months. Restoration chipping was measured using modified United States Public Health Services (USPHS) criteria. Results: All restorations were reported as alpha with no chipping. There was no statistically significant difference between (Group 1) and (Group 2) for wear test. Conclusion: Both monolithic and veneered restorations revealed satisfactory mechanical properties with no chipping after one year of clinical use. Wear of opposing enamel was clinically acceptable for both materials. Keywords Ceramics; Chipping; Monolithic zirconia; Veneered zirconia; Wear.

scholarly journals Flexural Strength of Different Monolithic Computer-Assisted Design and Computer-Assisted Manufacturing Ceramic Materials upon Different Thermal Tempering Processes

2020 ◽  
Vol 14 (04) ◽  
pp. 566-574
Author(s):  
Niwut Juntavee ◽  
Pithiwat Uasuwan
Keyword(s):  
Flexural Strength ◽  
Tetragonal Zirconia ◽  
Ceramic Materials ◽  
Bending Test ◽  
Lithium Silicate ◽  
Computer Assisted ◽  
Three Point Bending ◽  
Significant Difference ◽  
Monolithic Zirconia ◽  
Thermal Tempering

Abstract Objective Strength of ceramics related with sintering procedure. This study investigated the influence of different tempering processes on flexural strength of three monolithic ceramic materials. Materials and Methods  Specimens were prepared in bar-shape (width × length × thickness = 4 × 14 × 1.2 mm) from yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP, inCoris TZI [I]), zirconia-reinforced lithium silicate (ZLS, Vita Suprinity [V]), and lithium disilicate (LS2, IPS e.max CAD [E]), and sintered with different tempering processes: slow (S), normal (N), and fast (F) cooling procedure (n = 15/group). Flexural strength (σ) was determined using three-point bending test apparatus at 1 mm/min crosshead speed. Statistical Analysis  The analysis of variance and Bonferroni’s multiple comparisons were determined for significant difference (α = 0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristics strength (σo). Microstructures were evaluated with scanning electron microscope and X-ray diffraction. Results  The mean ± standard deviation (MPa) of σ, m, and σo were: 1,183.98 ± 204.26, 6.23, 1,271.80 for IS; 1,084.43 ± 204.79, 5.76, 1,170.08 for IN; 777.19 ± 99.77, 8.78, 819.96 for IF; 267.15 ± 32.71, 9.11, 281.48 for VS; 218.43 ± 38.46, 6.40, 234.23 for VN; 252.67 ± 37.58, 7.20, 269.23 for VF; 392.09 ± 37.91, 11.37, 409.23 for ES; 378.88 ± 55.38, 7.45, 403.11 for EN, and 390.94 ± 25.34, 16.00, 403.51 for EF. Thermal tempering significantly affected flexural strength of Y-TZP (p < 0.05), but not either ZLS or LS2 (p > 0.05). Y-TZP indicated significantly higher flexural strength upon slow tempering than others. Conclusion  Enhancing flexural strength of Y-TZP can be achieved through slow tempering process and was suggested as a process for monolithic zirconia. Strengthening of ZLS and LS2 cannot be accomplished through tempering; thus, either S-, N-, or F- tempering procedure can be performed. Nevertheless, to minimize sintering time, rapid thermal tempering is more preferable for both ZLS and LS2.

scholarly journals Effect of pH Cycling Frequency on Glass–Ceramic Corrosion

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3655
Author(s):  
Shu-Min Hsu ◽  
Fan Ren ◽  
Christopher D. Batich ◽  
Arthur E. Clark ◽  
Dan Neal ◽  
...  
Keyword(s):  
Weight Loss ◽  
Glass Ceramic ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Ceramic Materials ◽  
Ion Concentration ◽  
Ion Release ◽  
Effect Of Ph ◽  
Ph Changes ◽  
Glass Ceramic Materials

The effect of pH changes on the chemical durability of dental glass–ceramic materials was evaluated using weight loss and ion release levels. The hypothesis that increased pH changes will exhibit greater corrosion was investigated. The ion concentration was analyzed using inductively coupled plasma atomic emission spectrometer (ICP). The surface compositions were investigated using X-ray photoelectron spectroscopy (XPS). The surface morphologies were examined using scanning electron microscopy (SEM). Dental glass–ceramics were tested in constant immersion, 3-day cycling, and 1-day cycling with pH 10, pH 2, and pH 7 for 3, 15, and 30 days. The 1-d cycling group demonstrated the highest levels of weight loss compared with 3-d cycling and constant immersion. For the ion release, Si4+ and Ca2+ had the highest rates of release in 1-d cycling, whereas the Al3+ release rate with constant pH 2 was highest. The alteration/passivation layer that was formed on the surface of disks possibly prevented further dissolution of pH 10 corroded disks. XPS analysis demonstrated different surface compositions of corroded disks in pH 10 and pH 2. Si4+, K+, Na+, Al3+, and Ca2+ were detected on the surface of corroded pH 10 disks, whereas a Si4+ and P5+-rich surface formed on corroded pH 2 disks. SEM results demonstrated rougher surfaces for corroded disks in cycling conditions and pH 2 constant immersion. In conclusion, increased pH changes significantly promote the corrosion of dental glass–ceramic materials.

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