scholarly journals Vertical Marginal gap and internal fit of two types of fully anatomic zirconia crowns constructed by different CAD/CAM system

2018 ◽  
Vol 64 (1) ◽  
pp. 475-483
Author(s):  
Tarek Abdel Hamid ◽  
Diaaeldin Awad ◽  
Mosaad Al-gabrouny ◽  
Osama Atta
Keyword(s):  
Marginal Gap ◽  
Cad Cam ◽  
Zirconia Crowns ◽  
Internal Fit

scholarly journals Marginal and Internal Fit of Ceramic Prostheses Fabricated from Different Chairside CAD/CAM Systems: An In Vitro Study

2021 ◽  
Vol 11 (2) ◽  
pp. 857
Author(s):  
Keunbada Son ◽  
Kyu-Bok Lee
Keyword(s):  
Computer Aided Design ◽  
In Vitro Study ◽  
Vitro Study ◽  
Marginal Gap ◽  
Significant Difference ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Internal Fit ◽  
Cam Systems

The purpose of this in vitro study was to evaluate marginal and internal fits of ceramic crowns fabricated with chairside computer-aided design and manufacturing (CAD/CAM) systems. An experimental model based on ISO 12836:2015 was digitally scanned with different intraoral scanners (Omnicam (CEREC), EZIS PO (DDS), and CS3500 (Carestream)). Ceramic crowns were fabricated using the CAD/CAM process recommended by each system (CEREC, EZIS, and Carestream systems; N = 15). The 3-dimensional (3D) marginal and internal fit of each ceramic crown was measured using a 3D inspection software (Geomagic control X). Differences among the systems and various measurements were evaluated using the Kruskal–Wallis test. Statistically significant differences were validated using pairwise comparisons (α = 0.05). Occlusal gaps in the CEREC, EZIS, and Carestream groups were 113.0, 161.3, and 438.2 µm, respectively (p < 0.001). The axial gaps were 83.4, 78.0, and 107.9 µm, respectively. The marginal gaps were 77.8, 99.3, and 60.6 µm, respectively, and the whole gaps were 85.9, 107.3, and 214.0 µm, respectively. Significant differences were observed with the EZIS system compared with the other two systems in terms of the marginal gap sizes. The CEREC system showed no significant differences among the four measured regions. However, the EZIS and Carestream systems did show a statistically significant difference (p < 0.05). All three systems were judged to be capable of fabricating clinically acceptable prostheses, because the marginal gap, which is the most important factor in the marginal fit of prostheses, was recorded to be below 100 µm in all three systems.

Effect of imaging powder and CAD/CAM stone types on the marginal gap of zirconia crowns

2015 ◽  
Vol 146 (2) ◽  
pp. 111-120 ◽  
Author(s):  
Tariq F. Alghazzawi ◽  
Khalid H. Al-Samadani ◽  
Jack Lemons ◽  
Perng-Ru Liu ◽  
Milton E. Essig ◽  
...  
Keyword(s):  
Marginal Gap ◽  
Cad Cam ◽  
Zirconia Crowns

scholarly journals In Vitro Comparison of Marginal and Internal Fit of Zirconia Copings Fabricated by One CAD/CAM System with Two Different Scanners

2021 ◽  
Author(s):  
Zahra Khamverdi1 ◽  
Elmira Najafrad ◽  
Maryam Farhadian
Keyword(s):  
T Test ◽  
Marginal Fit ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
The Mean ◽  
Internal Fit ◽  
Paired T Test

Objectives: Marginal and internal fit of restorations are two important clinical factors for assessing the quality and durability of computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated monolithic zirconia restorations. The purpose of this study was to evaluate the marginal and internal fit of CAD/CAM zirconia crowns with two different scanners (i3D scanner and 3Shape D700). Materials and Methods: Twelve extracted sound human posterior teeth were prepared for full zirconia crowns. Two different extraoral scanners namely i3D scanner and 3Shape D700 were used to digitize type IV gypsum casts poured from impressions. The crowns were milled from presintered monolithic zirconia blocks by a 5-axis milling machine. The replica technique and MIP4 microscopic image analysis software were utilized to measure the marginal and internal fit by a stereomicroscope at ×40 magnification. The collected data were analyzed by paired t-test. Results: The mean marginal gap was 203.62 μm with 3Shape D700 scanner and 241.07 μm with i3D scanner. The mean internal gap was 192.30 μm with 3Shape D700 scanner and 196.06 μm with i3D scanner. The results of paired t-test indicated that there was a statistically significant difference between the two scanners in marginal fit (P=0.04); while, there was no statistically significant difference in internal fit (P=0.761). Conclusion: Within the limitations of this study, the results showed that type of extraoral scanner affected the marginal fit of CAD/CAM fabricated crowns; however, it did not have a significant effect on their internal fit.

scholarly journals Marginal and Internal Precision of Zirconia Four-Unit Fixed Partial Denture Frameworks Produced Using Four Milling Systems

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2663
Author(s):  
Karl Martin Lehmann ◽  
Michael Weyhrauch ◽  
Monika Bjelepavlovic ◽  
Herbert Scheller ◽  
Henning Staedt ◽  
...  
Keyword(s):  
Marginal Gap ◽  
Partial Denture ◽  
System A ◽  
Fixed Partial Denture ◽  
Bonferroni Adjustment ◽  
Cad Cam ◽  
Level Of Significance ◽  
Internal Fit ◽  
Cam Systems ◽  
Marginal Region

Background: CAD/CAM systems enable the production of fixed partial dentures with small and reproducible internal and marginal gaps. Purpose: The purpose of this study was to evaluate the reproducibility of the marginal and internal adaptations of four-unit fixed partial denture frameworks produced using four CAD/CAM systems. Materials and Methods: Prepared dies of a master model that simulated the loss of the first left molar were measured. Fifteen frameworks were manufactured using four CAD/CAM systems (A–D). The internal fit was determined by the replica technique, and the marginal gap was determined by microscopy. ANOVA was carried out to detect significant differences, and the Bonferroni adjustment was performed. The global level of significance was set at 5%. Results: The mean gap size ranged from 84 to 132 µm (SD 43–71 µm). The CAD/CAM systems showed significant variance (p < 0.001), and system A (VHF) showed the smallest gaps. The smallest gaps for each system were in the molar part and in the marginal region of the frameworks (p < 0.001). Conclusions: The CAD/CAM systems showed significantly different gap sizes, particularly between premolars and molars and among the marginal, axial and occlusal regions. All of the systems are suitable for clinical application.

scholarly journals Effect of Sintering Time on The Marginal and Internal Fit of Monolithic Zirconia Crowns Containing 3-4 Mol% Y2O3

2021 ◽  
Author(s):  
Yunus Emre Ozden ◽  
M.Baris Guncu ◽  
Guliz Aktas ◽  
Senay Canay
Keyword(s):  
Tetragonal Zirconia ◽  
Cubic Phase ◽  
Marginal Gap ◽  
Sintering Time ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
The Mean ◽  
Internal Fit ◽  
Tetragonal Zirconia Polycrystal ◽  
Gap Values

Abstract Background Short-time sintering may offer advantages including saving time and energy but there is limited evidence on the effect that altering sintering time has on the accuracy of monolithic zirconia crowns. The purpose of this in vitro study was to investigate the effect of shortened sintering time on the marginal and internal fit of 3Y-TZP (three mol% yttria-stabilized tetragonal zirconia polycrystal) and 4Y-TZP (four mol% yttria-stabilized tetragonal zirconia polycrystal) monolithic crowns. Methods Sixty monolithic zirconia crowns were fabricated for the maxillary first molar tooth on the prefabricated implant abutment. Groups were created according to the material composition: 3Y-TZP Generation 1 (alumina wt; ≤0.5%, < 15% cubic phase), 3Y-TZP Generation 2 (alumina wt; ≤0.05%, < 15% cubic phase) and 4Y-TZP (alumina wt; ≤0.05%, > 25% cubic phase). Two different sintering protocols were performed: same final sintering temperature (1500°C) and various rates of heating (10°C/min and 40°C/min), cooling down speed (-10°C/min and − 40°C/min), holding time (45 and 120 minutes), and total sintering time (approximately 2 and 7 hours, respectively). The marginal and internal fit of the crowns were determined using the silicone replica technique. Comparisons between groups and sintering times were analyzed using two-way ANOVA. Pairwise multiple comparisons were performed using the t-test (p < 0.05). Results The mean marginal gap values of 4Y-TZP zirconia revealed statistically significant increase for the speed sintering protocol (p < 0.0001), while no difference was observed between the sintering protocols for the mean marginal gap values of 3Y-TZP groups. Conclusions Although all groups showed clinically acceptable gap values (<120 µm), altering the sintering time had an effect on the marginal fit of the crowns manufactured from 4Y-TZP zirconia. Shortening the sintering time may lead to differences within clinically acceptable limits. The manufacturer's recommendations according to material composition should be implemented with care.

scholarly journals The effect of off-axis seating on the marginal adaptation of full coverage all ceramic crowns

2020 ◽  
Vol 75 (6) ◽  
pp. 303-310
Author(s):  
George P Babiolakis ◽  
C Peter Owen
Keyword(s):  
In Vitro Study ◽  
Axial Direction ◽  
Three Dimensions ◽  
Marginal Gap ◽  
Cad Cam ◽  
3D Printed ◽  
Ceramic Crowns ◽  
Crown Preparation ◽  
Internal Fit

INTRODUCTION: No studies on the marginal gap or internal fit of crowns have reported the effect of non-axial seating which may often occur inadvertently clinically. AIM: Therefore this in vitro study sought to investigate the off-axis seating of CAD/CAM crowns and its effect on the marginal gap and internal fit. METHOD: A standardised crown preparation on a typodont tooth was used to design and mill 30 crowns with a flat occlusal surface. Ten Zirconia (Dentsply Sirona, Germany), 10 Enamic (Vita, Austria), and 10 Brilliant Crios (Coltene, Switzerland) crowns were milled, Ave of each milled with a luting space of 100µm, and Ave of 200µm. The marginal gap was measured in two and three dimensions after luting with silicone on a 3D-printed metal replica. Seating occurred axially, at 5° buccally and 5° lingually. The silicone was used to calculate the internal fit RESULTS: Axial seating with a 100 µm luting space obtained the smallest marginal gap, irrespective of material or luting space. 3D measurements were larger than 2D measurements, but not significantly. The maximum off-axis gap was 117µm, on the opposite side to which pressure was applied. CONCLUSIONS: Care must be taken clinically to ensure that luting takes place in an axial direction only.

scholarly journals Evaluation of Marginal Gap / Fit of Zirconia Copings & Full Contoured Monolith Zirconia Crowns (CAD / CAM) - A Comparative In-Vitro Study

2021 ◽  
Vol 10 (20) ◽  
pp. 1483-1488
Author(s):  
Liya Zacharias
Keyword(s):  
Experimental Study ◽  
P Value ◽  
Marginal Gap ◽  
Marginal Fit ◽  
Type Iv ◽  
Significant Difference ◽  
Cad Cam ◽  
Zirconia Crowns ◽  
Group 2

BACKGROUND Inadequate marginal fit of fixed restorations leads to plaque accumulation, recurrent caries and periodontal problems. The purpose of this experimental study is to evaluate and compare the marginal fit/gap of computer-aided design and computeraided manufacturing (CAD/CAM) fabricated zirconia copings and zirconia full contoured monolith crowns fabricated on type IV gypsum die having a definite cement spacer thickness of 0.05mm. METHODS This is an in-vitro experimental study carried out from November 2018 to November 2019. A master stainless steel die was used to make 52 type IV die stone models which were randomly divided into 2 groups of 26 samples each. Group 1: zirconia copings and group 2: zirconia monolith full contoured crowns. These restotations were fabricated using CAD/CAM. The marginal gap of each zirconia copings and zirconia full contoured crowns was assessed using scanning electron microscopic analysis on four different pre-marked points (GEMINI SEM 500; ZEISS). Observations were tabulated and analyzed statistically. Independent t-test was used to compare the measurements between zirconia copings & zirconia monolith crowns. RESULTS The least marginal gap observed was for group 2 (zirconia full contoured crown) with a mean value of 29.88 ± 9.16 μm while that of group1 (zirconia coping) was 73.64 ± 28.13 μm. There was a statistically significant difference in the measurements between zirconia copings and zirconia full contoured monolith crowns (P - value < 0.001). There was statistically significant difference in each side of zirconia monolith crowns when compared to the corresponding side of zirconia copings (P - Value < 0.001). CONCLUSIONS CAD/CAM milled full contoured zirconia crowns showed least marginal discrepancy when compared to zirconia copings. All samples had marginal gap within the clinically acceptable range of 120 μm. KEY WORDS Monolith, Zirconia Crowns, Zirconia Copings, Full Contoured Crowns, CAD-CAM

Marginal and Internal Fit of Monolithic and Veneered Zirconia Crowns

2019 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Mai Mohammed Faek ◽  
Mona hossam ◽  
Rania Amin Shetawy
Keyword(s):  
Zirconia Crowns ◽  
Internal Fit

The Effect of Thickness on the Fracture Strength and Failure Modes of Zirconia Crowns

2016 ◽  
Vol 697 ◽  
pp. 629-632
Author(s):  
Li Xian Zhang ◽  
Rui Li ◽  
Yu Niu ◽  
Yu Xiao Liu
Keyword(s):  
Fracture Strength ◽  
Failure Modes ◽  
Statistical Significance ◽  
Dental Practice ◽  
Significant Difference ◽  
Cad Cam ◽  
Zirconia Crowns ◽  
Different Thickness

To explore the effect of thickness on the fracture strength and failure modes of zirconia crowns, four crown models with different thickness (1.2 mm, 1.0 mm, 0.8 mm, 0.6 mm) with the same shape were designed by Dental Designer software in CAD/CAM system. They were manufactured to 40 zirconia crowns by CAM carving machine. The fracture strength and the failure modes of each crown was measured, while porcelain fused to metal (PFM) crowns as control. The average fracture strength of different zirconia crowns were recorded as below: 1308.38 ± 111.38 N (Group 0.6 mm), 1841.60 ± 68.21 N (Group 0.8 mm), 2429.88 ± 315.03 N (Group 1.0 mm), 3068.31 ± 233.88 N (Group 1.2 mm). There was no significant difference between Group 1.0 mm and Group 1.2 mm (P > 0.05), and statistical significance was obtained among every other two groups (P < 0.05). The failure modes of different thickness zirconium crowns are similar. There are more broken pieces from thicker crowns compared to thinner ones. It is concluded that the thickness can influence the fracture strength of zirconia crown. With the increase of the thickness, the fracture strength of the zirconium crowns also increases. We recommend zirconia crowns thicker than or at least 1.0 mm in dental practice.

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