Digital microscopic evaluation of vertical marginal discrepancies of CAD/CAM fabricated zirconia cores

2019 ◽  
Vol 64 (2) ◽  
pp. 207-214 ◽  
Author(s):  
Syed Rashid Habib
Keyword(s):  
Computer Aided Design ◽  
Microscopic Evaluation ◽  
Significant Difference ◽  
Digital Microscope ◽  
Cad Cam ◽  
Marginal Discrepancy ◽  
Aided Design ◽  
Post Hoc ◽  
Cam Systems

Abstract Objective: The aim of this in vitro research study was to evaluate the vertical marginal discrepancies of zirconia (Zr) cores fabricated by five different computer-aided design and manufacturing (CAD/CAM) systems using a digital microscope. Materials and methods: A total of 60 specimens were prepared and randomly divided into five groups (n=12 each) using the following systems: Ceramill Motion 2 (CM, Amanngirrbach, Germany); Weiland (WI, Ivoclar Vivadent, USA); Cerec (CS, Sirona Dental, USA); Zirkonzahn (ZZ, Gmbh Bruneck, Italy) and Cad4dent (CD, Canada). The specimens were numbered and the vertical marginal discrepancies were evaluated with a digital microscope at 50× magnification. Results: A one-way analysis of variance showed a statistically significant difference (p=0.002) between the groups. The CM group exhibited the lowest values for the marginal gaps (31.30±15.12 μm), while the ZZ group exhibited the highest values for the marginal gaps (44.83±28.76 μm) compared to other groups. A post hoc Tukey’s test for multiple comparisons between the experimental groups showed a statistically significant difference (p<0.05) between the group CM and group CD with group ZZ. The rest of the groups showed no significant differences between them. Variations in the values were observed for the four sites measured with the highest and the least mean marginal gap value of 43.19±23.84 μm and 32.49±12.21 μm for buccal and lingual sites, respectively. Conclusion: Variations existed in the marginal discrepancy values for the CAD/CAM systems investigated in the study. Vertical marginal discrepancy values observed for various systems investigated in the study were well within the clinically acceptable range.

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.

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

2020 ◽  
Vol 23 (4) ◽  
pp. 9p
Author(s):  
Manar Ahmed El-Mahdy ◽  
Ahmed Khaled Aboelfadl ◽  
Marwa Mohamed Wahsh
Keyword(s):  
In Vitro Study ◽  
Lithium Silicate ◽  
Milling Machine ◽  
Marginal Fit ◽  
Cad Cam ◽  
Marginal Discrepancy ◽  
Post Hoc ◽  
Laminate Veneers ◽  
Cam Systems

ABSTRACTObjective: 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.

scholarly journals Marginal Gap Evaluation of Metal Onlays and Resin Nanoceramic Computer-Aided Design and Computer-Aided Manufacturing Blocks Onlays

2019 ◽  
Vol 13 (01) ◽  
pp. 017-021
Author(s):  
Nor Faharina Abdul Hamid ◽  
Wan Zaripah Wan Bakar ◽  
Zaihan Ariffin
Keyword(s):  
Statistical Analysis ◽  
Computer Aided Design ◽  
Marginal Gap ◽  
Computer Aided Manufacturing ◽  
Promising Alternative ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design

Abstract Objective This study was carried out to assess and compare the marginal gap of conventionally used metal onlays and new resin nanoceramic (RNC) (Lava Ultimate block) onlays. Materials and Methods This is an in vitro study using two extracted sound human mandibular molars. One tooth was prepared to receive the metal onlays and another one for the RNC onlays which were fabricated using the computer-aided design and computer-aided manufacturing (CAD/CAM) technology. Twelve metals and 12 ceramic onlays were fabricated before they were placed at their respective preparation and examined under the Leica stereomicroscope, M125C (Leica Microsystems, Wetzlar, Germany) for a marginal analysis. The gap width was measured at 10 predefined landmarks which included 3 points on the buccal and lingual surfaces each and 2 points each on the mesial and distal surfaces, respectively. Statistical Analysis Mann–Whitney post hoc test was used for statistical analysis (P ≤ 0.05). Results Overall, the RNC onlays showed significant lower marginal gap with the exception of the landmarks 5 and 6 (on distolingual) and no significant difference at landmark 7 (on midlingual). It was observed that the marginal gap were all within the clinically acceptable limit of 120 μm. Conclusions Based on the results obtained, it can be concluded that the RNC CAD/CAM onlays are a promising alternative to the metal onlays.

scholarly journals (In-Vitro Comparison between Closed Versus Open CAD/CAM Systems) Comparison between Closed and Open CAD/CAM Systems by Evaluating the Marginal Fit of Zirconia-Reinforced Lithium Silicate Ceramic Crowns

2021 ◽  
Vol 11 (10) ◽  
pp. 4534
Author(s):  
Gil Ben-Izhack ◽  
Asaf Shely ◽  
Omer Koton ◽  
Avi Meirowitz ◽  
Shifra Levartovsky ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Open Systems ◽  
Lithium Silicate ◽  
Marginal Gap ◽  
Computer Aided ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Aided Design ◽  
Cam Systems

Background: This study compared the marginal gap (MG) and absolute marginal discrepancy (AMD) of computer-aided design and computer-aided manufacturing (CAD–CAM) used in open systems (OSs) and closed systems (CSs) for producing monolithic zirconia-reinforced lithium silicate (ZLS) ceramic crowns. Methods: 60 ZLS ceramic crowns were cemented to abutment acrylic teeth; thirty crowns were designed and milled by an OS, and thirty by a CS. All crowns were sectioned for evaluating the marginal gap by scanning electronic microscopy (SEM). To compare the marginal gap between CS and OS techniques, data were analyzed using the independent-samples Mann–Whitney U Test (α = 0.05). Results: AMD was found to be significantly better for the closed system (p < 0.05). Mean AMD values for the CS were 148 µm, and for the OS it was 196 µm. MG was found to be significantly better for the OS (p < 0.05). Mean MG values for the CS were 55 µm, and for the OS they were 38 µm. Conclusions: The marginal gap in relation to AMD was significantly better for CS. However, the marginal gap in relation to MG was significantly better for OS. Both techniques showed clinically acceptable MG values (<120 µm).

Design of special tools by CAD/CAM systems

1998 ◽  
Vol 212 (5) ◽  
pp. 357-371
Author(s):  
J C Rico ◽  
S Mateos ◽  
E Cuesta ◽  
C M Suárez
Keyword(s):  
Computer Aided Design ◽  
Automatic Identification ◽  
Automatic Design ◽  
Technological Parameters ◽  
Optimum Cutting ◽  
Cad Cam ◽  
The Cost ◽  
Aided Design ◽  
Cam Systems ◽  
Selection Of

This paper presents a program for the automatic design of special tools developed under a CAD/CAM (computer aided design/manufacture) system. In particular, the special tools made with standard components have been considered. Since the design of these types of tools was essentially related to the selection of their components, this paper deals with this aspect, insisting upon the selection of those components directly related to the removal of material: the toolholders or cartridges and the inserts. To select these components it is necessary to take into account not only geometrical or technological rules but also economical ones, owing to the high amount of possible components they can select. Consideration of economical aspects required the formulation of the cost equation associated with the use of these types of tools, characterized because their cutting edges coincide with different cutting velocities. Likewise, consideration of economical aspects allows the selection of the optimum cutting conditions and the cutting components to take place at the same time. Some of the geometrical and technological parameters related to the selection of cutting components are automatically identified by the system through an automatic identification of the workpiece profile.

Premolar Axial Wall Height Effect on CAD/CAM Crown Retention

2016 ◽  
Vol 41 (6) ◽  
pp. 666-671 ◽  
Author(s):  
C Gillette ◽  
R Buck ◽  
N DuVall ◽  
S Cushen ◽  
M Wajdowicz ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
Failure Resistance ◽  
All Ceramic ◽  
Computer Aided ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Aided Design ◽  
Post Hoc

SUMMARY Objective: To evaluate the significance of reduced axial wall height on retention of adhesively luted, all-ceramic, lithium disilicate premolar computer-aided design/computer-aided manufacturing (CAD/CAM) crowns based on preparations with a near ideal total occlusal convergence of 10°. Methods: Forty-eight recently extracted premolars were randomly divided into four groups (n=12). Each group received all-ceramic CAD/CAM crown preparations featuring axial wall heights of 0, 1, 2, and 3 mm, respectively, all with a 10° total occlusal convergence. Scanned preparations were fitted with lithium disilicate all-ceramic crowns that were luted with a self-etching resin cement. Specimens were tested to failure at a 45° angle to the tooth long axis with failure load converted to megapascals (MPa) based on the measured bonding surface area. Mean data were analyzed using analysis of variance/Tukey's post hoc test (α=0.05). Results: Lithium disilicate crowns adhesively luted on preparations with 0 axial wall height demonstrated significantly less failure resistance compared with the crowns luted on preparations with axial wall heights of 1 to 3 mm. There was no failure stress difference between preparations with 1 to 3 mm axial wall height. Conclusions: Under conditions of this study, adhesively luted lithium disilicate bicuspid crowns with a total occlusal convergence of 10° demonstrated similar failure resistance independent of axial wall height of 1 to 3 mm. This study provides some evidence that adhesion combined with an ideal total occlusal convergence may compensate for reduced axial wall height.

Effects of Polishing Bur Application Force and Reuse on Sintered Zirconia Surface Topography

2018 ◽  
Vol 43 (4) ◽  
pp. 437-446 ◽  
Author(s):  
NG Fischer ◽  
A Tsujimoto ◽  
AG Baruth
Keyword(s):  
Surface Topography ◽  
Computer Aided Design ◽  
Groove Depth ◽  
Control Group ◽  
Limited Information ◽  
Average Roughness ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam

SUMMARY Objective: Limited information is available on how to polish and finish zirconia surfaces following computer-aided design/computer-aided manufacturing (CAD/CAM), specifically, how differing application forces and reuse of zirconia polishing systems affect zirconia topography. Purpose: To determine the effect of differing, clinically relevant, polishing application forces and multiple usages of polishing burs on the surface topography of CAD/CAM zirconia. Methods: One hundred twenty 220-grit carbide finished zirconia disks were sintered according to manufacturer's directions and divided into two groups for the study of two coarse polishing bur types. Each group was divided into subgroups for polishing (15,000 rpm) at 15 seconds for 1.0 N, 4.5 N, or 11 N of force using a purpose-built fixture. Subgroups were further divided to study the effects of polishing for the first, fifth, 15th, and 30th bur use, simulating clinical procedures. Unpolished surfaces served as a control group. Surfaces were imaged with noncontact optical profilometry (OP) and atomic force microscopy (AFM) to measure average roughness values (Ra). Polishing burs were optically examined for wear. Scanning electron microscopy (SEM) was performed on burs and zirconia surfaces. One-way ANOVA with post hoc Tukey HSD (honest significant difference) tests (α=0.05) were used for statistical analyses. Results: AFM and OP Ra values of all polished surfaces were significantly lower than those of the unpolished control. Different polishing forces and bur reuse showed no significant differences in AFM Ra. However, significant differences in OP Ra were found due to differing application forces and bur reuse between the first and subsequent uses. SEM and optical micrographs revealed notable bur wear, increasing with increasing reuse. SEM and AFM micrographs clearly showed polished, periodic zirconia surfaces. Nanoscale topography, as analyzed with kurtosis and average groove depth, was found dependent on the specific polishing bur type. Conclusions: These in vitro results suggest changes in OP Ra due to bur reuse and polishing application force. Within the parameters of this study, the resultant topography of zirconia polishing is force-dependent and the reuse of coarse polishing burs is possible without statistically significant differences in Ra values after initial use. Nanoscale and microscale topography were shown to depend on specific polishing bur type.

scholarly journals Accuracy and Precision Evaluation of International Standard Spherical Model by Digital Dental Scanners

Scanning ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Hong Xin Cai ◽  
Qi Jia ◽  
HaoYu Shi ◽  
Yujie Jiang ◽  
Jingnan Xue ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Spherical Model ◽  
Scanning System ◽  
Sphere Model ◽  
Accuracy And Precision ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam ◽  
Fitting In ◽  
Aided Design

With the popularization of digital technology and the exposure of traditional technology’s defects, computer-aided design and computer-aided manufacturing (CAD/CAM) has been widely used in the field of dentistry. And the accuracy of the scanning system determines the ultimate accuracy of the prosthesis, which is a very important part of CAD/CAM, so we decided to evaluate the accuracy of the intraoral and extraoral scanners. In this study, we selected the sphere model as the scanning object and obtained the final result through data analysis and 3D fitting. In terms of trueness and precision, the scanner of SHINING was significantly different from that of others; however, there was no significant difference between TRIOS and CEREC. SHINING showed the lowest level of accuracy, with CEREC slightly lower than TRIOS. The sphere model has also been proven to be scanned successfully.

scholarly journals Effect of Tooth Types on the Accuracy of Dental 3D Scanners: An In Vitro Study

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1744 ◽  
Author(s):  
Keunbada Son ◽  
Kyu-bok Lee
Keyword(s):  
Computer Aided Design ◽  
Reference Model ◽  
Three Dimensional ◽  
In Vitro Study ◽  
Test Model ◽  
Intraoral Scanner ◽  
3D Scanners ◽  
Aided Design ◽  
Post Hoc

The purpose of this study was to evaluate the accuracy of dental three-dimensional (3D) scanners according to the types of teeth. A computer-aided design (CAD) reference model (CRM) was obtained by scanning the reference typodont model using a high-precision industrial scanner (Solutionix C500, MEDIT). In addition, a CAD test model (CTM) was obtained using seven types of dental 3D scanners (desktop scanners (E1 and DOF Freedom HD) and intraoral scanners (CS3500, CS3600, Trios2, Trios3, and i500)). The 3D inspection software (Geomagic control X, 3DSystems) was used to segment the CRM according to the types of teeth and to superimpose the CTM based on the segmented teeth. The 3D accuracy of the scanner was then analyzed according to the types of teeth. One-way analysis of variance (ANOVA) was used to compare the differences according to the types of teeth in statistical analysis, and the Tukey HSD test was used for post hoc testing (α = 0.05). Both desktop and intraoral scanners showed significant differences in accuracy according to the types of teeth (P < 0.001), and the accuracy of intraoral scanners tended to get worse from anterior to posterior. Therefore, when scanning a complete arch using an intraoral scanner, the clinician should consider the tendency for the accuracy to decrease from anterior to posterior.

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