scholarly journals Digital versus conventional techniques for pattern fabrication of implant-supported frameworks

2018 ◽  
Vol 12 (01) ◽  
pp. 071-076 ◽  
Author(s):  
Marzieh Alikhasi ◽  
Ahmad Rohanian ◽  
Safoura Ghodsi ◽  
Amin Mohammadpour Kolde
Keyword(s):  
Statistical Analysis ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Conventional Technique ◽  
Wax Pattern ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam ◽  
Level Of Significance ◽  
Post Hoc

ABSTRACT Objective: The aim of this experimental study was to compare retention of frameworks cast from wax patterns fabricated by three different methods. Materials and Methods: Thirty-six implant analogs connected to one-piece abutments were divided randomly into three groups according to the wax pattern fabrication method (n = 12). Computer-aided design/computer-aided manufacturing (CAD/CAM) milling machine, three-dimensional printer, and conventional technique were used for fabrication of waxing patterns. All laboratory procedures were performed by an expert-reliable technician to eliminate intra-operator bias. The wax patterns were cast, finished, and seated on related abutment analogs. The number of adjustment times was recorded and analyzed by Kruskal–Wallis test. Frameworks were cemented on the corresponding analogs with zinc phosphate cement and tensile resistance test was used to measure retention value. Statistical Analysis Used: One-way analysis of variance (ANOVA) and post hoc Tukey tests were used for statistical analysis. Level of significance was set at P < 0.05. Results: The mean retentive values of 680.36 ± 21.93 N, 440.48 ± 85.98 N, and 407.23 ± 67.48 N were recorded for CAD/CAM, rapid prototyping, and conventional group, respectively. One-way ANOVA test revealed significant differences among the three groups (P < 0.001). The post hoc Tukey test showed significantly higher retention for CAD/CAM group (P < 0.001), while there was no significant difference between the two other groups (P = 0.54). CAD/CAM group required significantly more adjustments (P < 0.001). Conclusions: CAD/CAM-fabricated wax patterns showed significantly higher retention for implant-supported cement-retained frameworks; this could be a valuable help when there are limitations in the retention of single-unit implant restorations.

The Accuracy of Optical Scanning: Influence of Convergence and Die Preparation

2011 ◽  
Vol 36 (5) ◽  
pp. 486-491 ◽  
Author(s):  
DCN Chan ◽  
AK-H Chung ◽  
J Haines ◽  
EH-T Yau ◽  
C-C Kuo
Keyword(s):  
Surface Area ◽  
White Light ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Area Measurement ◽  
Finish Line ◽  
Optical Scanner ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam

SUMMARY The purpose of this study was to determine the reliability of the data acquisition and modeling process of laser and white light scanners by evaluating the reproducibility of digitized simulated crowns with different convergences. A secondary purpose was to analyze the influence of die preparation by testing this hypothesis with a set of dies without ditching compared with a set with well-defined margins. Ditching or trimming the die defines the position of the margin and acts as a guide to gingival contour when the restoration is being waxed. Two light scanners (a white light optical scanner [Steinbichler Gmbh, Neubeuern, Germany] and red laser light scanner [TurboDent System, Taichung, Taiwan]) were evaluated. Two sets of simulated crowns were fabricated as cone frustrum models with a total occlusal convergence (TOC) of 0°, 5°, 10°, 15°, 20°, and 25° and a 9-mm base and 3-mm height using a precision milling machine and computer-aided design/computer-aided manufacturing (CAD/CAM) technique. One set of the dies was ditched immediately below the finish line to enhance marginal definition. Each die was optically digitized five times directly with the two different measuring systems. The area of each triangle in the scan that is occlusal to the margin line was calculated and summed to produce the final surface area measurement provided. The digitizing error was compared with the computed surface area of the original master die sets and compared with a paired t-test (df=4; 95% CI). There was no difference in accuracy of the untrimmed dies between the two systems evaluated. We also did not find any difference in the 0° (p=0.12) and 5° degree (p=0.21) groups among the ditched dies. However, when the TOC exceeded 5°, there was a significant difference between the two groups, with the laser groups having a smaller error percentage. Three-dimensional light scanning was not affected by the convergence angle except in the 0°-5° range. Trimming the dies greatly affected the accuracy of scanning.

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.

Evaluation of Polishing Systems for CAD/CAM Polymer-Infiltrated Ceramic-Network Restorations

2021 ◽  
Author(s):  
CA Jurado ◽  
A Tsujimoto ◽  
H Watanabe ◽  
NG Fischer ◽  
JA Hasslen ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Computer Aided Design ◽  
Dental Students ◽  
Faculty Members ◽  
Dental School ◽  
Control Group ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam ◽  
A Company

SUMMARY Objective: The purpose of this study was to evaluate the effectiveness of five different polishing systems on a computer-aided design and computer-aided manufacturing (CAD/CAM) polymer-infiltrated ceramic-network restoration with nanoscale assessment using atomic force microscopy (AFM) and visual assessment performed by dental school senior students and faculty members. Method: Forty-eight full coverage crowns were milled out of polymer-infiltrated ceramic-network CAD/CAM blocks (Vita Enamic) for polishing with one company proprietary, two ceramic and two composite polishing systems. The prepared crowns were divided into six groups: (1) no polishing (control); (2) polishing with Vita Enamic Polishing Kit (VEna); (3) polishing with Shofu Porcelain Laminate Polishing Kit (SCer); (4) polishing with Brasseler Dialite Feather lite All- Ceramic Adjusting & Polishing System (BCer); (5) polishing with Shofu Composite Polishing Kit (SCom); and (6) polishing with Brasseler Composite Polishing Kit (BCom). The polished crown surface topography was observed, and surface roughness and area were measured with AFM. In addition, polished crowns were visually assessed by 15 senior dental students and 15 dental school faculty members. Results: All polishing treatments significantly reduced the surface roughness and area of the crown compared with the control. SCom and BCom showed significantly higher surface area than VEna, and the SCer and BCer groups were intermediate, showing no significant difference from either VEna or SCom and BCom. There were no significant differences in surface roughness between any of the systems. Dental students and faculty members classified the groups polished with VEna, SCer, and BCer groups as clinically acceptable, and they selected BCer group as the best polished restorations and the control group as the least polished restorations. Conclusions: Ceramic and composite polishing systems produced similar polishing results as that observed using a company proprietary polishing system. However, effectiveness for polishing using a company proprietary and ceramic polishing system tends to be higher than composite polishing systems.

scholarly journals Monitoring Alveolar Ridge Remodelling Post-Extraction Using Sequential Intraoral Scanning over a Period of Four Months

2020 ◽  
Vol 17 (18) ◽  
pp. 6638
Author(s):  
Khaled E. Ahmed
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Dimensional Changes ◽  
Intraoral Scanning ◽  
Computer Aided ◽  
Potential Applications ◽  
Cad Cam ◽  
Aided Design ◽  
2D And 3D

The potential applications of computer-aided design/computer-aided manufacturing (CAD/CAM) and intraoral scanning exceed the delivery of standard prosthodontic interventions. The aim of this study was to clinically present a developed assessment technique, that relies on the use of sequential intraoral scanning, three-dimensional superimposition, and 2D and 3D deviation analyses based on a standardised protocol, as an auxiliary tool in monitoring dimensional changes of residual ridge post-extraction with a follow-up period of four months.

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 VIRTUAL TECHNOLOGIES IN DENTISTRY

2020 ◽  
pp. 606-612
Author(s):  
S.V. KAZUMYAN ◽  
◽  
I.A. DEGTEV ◽  
V.V. BORISOV ◽  
K.A. ERSHOV
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Interdisciplinary Treatment ◽  
Digital Dentistry ◽  
Dental Restorations ◽  
Technological Advances ◽  
Planning Approach ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design

The article represents the information that in the age of digital dentistry, virtual treatment planning is becoming an increasingly important element of dental practice. With new technological advances in computer-aided design and computer-aided manufacturing (CAD/CAM) of dental restorations, predictable interdisciplinary treatment using a reverse planning approach appears to be beneficial and feasible. It is noted that thanks to achievements in medical imaging and computer programming, 2D axial images can be processed into other reformatted representations (sagittal and coronal) and three-dimensional (3D) virtual models representing the patient’s anatomy. It is shown that telemedicine occupies a special place among modern technologies in dentistry, which is used both for remote consultation and for the successful treatment of patients. Keywords: Virtual assistants , virtual nurses, voice technologies, artificial intelligence, virtual reality, 3D printing, telemedicine.

scholarly journals Different fabrication techniques of implant-supported prostheses

2019 ◽  
Vol 18 ◽  
pp. e191573
Author(s):  
Silas Monteiro Borges ◽  
Stephanie Francoi Poole ◽  
Izabela Cristina Maurício Moris ◽  
Aloísio Oro Spazzin ◽  
Adriana Cláudia Lapria Faria ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Computer Aided Design ◽  
Fracture Load ◽  
Fracture Pattern ◽  
Thermomechanical Cycling ◽  
Significant Difference ◽  
Computer Aided ◽  
Before And After ◽  
Cad Cam ◽  
Manufacturing Techniques

Aim: This study evaluated the mechanical behavior of implant-supported crowns obtained by different fabrication technique after thermomechanical cycling. Methods: Thirty-two external hexagon dental implants were divided into four groups (n=10): CC – conventional casting with torch; EI – electromagnetic induction casting; PL – plasma casting; and CAD-CAM – milling through computer-aided design and computer-aided manufacturing. Vickers microhardness of the specimens were made before and after the thermomechanical cycling, and then subjected to fracture load. Fracture pattern was evaluated. Results: No significant difference was observed comparing the microhardness before and after thermomechanical cycling. CAD-CAM group presented significant lower microhardness than the other groups. No significant statistical difference was showed on fracture load between the groups. The CAD-CAM and PL presented lower number of failure by plastic deformation. Conclusion: The manufacturing techniques affected the mechanical behavior and the failure pattern of implant-supported crowns tested.

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 Evaluation of the light transmission of chairside polymer infiltrated hybrid ceramics in different shades and thicknesses

2019 ◽  
Vol 17 (1) ◽  
pp. 228080001880710 ◽  
Author(s):  
İbrahim Duran ◽  
Necati Kaleli ◽  
Çağrı Ural ◽  
İdris Kavut
Keyword(s):  
Computer Aided Design ◽  
Light Transmission ◽  
Univariate Analysis ◽  
Control Group ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam ◽  
Lower Light ◽  
Hybrid Ceramic

Background: This in vitro study aimed to evaluate the amount of polymerizing light passing through hybrid ceramic specimens in different shades and thicknesses. Methods: Rectangular-shaped feldspathic ceramic computer aided design and computer aided manufacturing (CAD-CAM) blocks and translucent and high translucent polymer infiltrated hybrid ceramic CAD-CAM blocks in four different shades (1M1, 1M2, 2M2, and 3M2) were sectioned in four different thicknesses (0.8, 1.5, 2, and 3 mm), and a total of 48 groups ( n = 10) were obtained. Feldspathic ceramic specimens served as the control group. The light transmission of each ceramic specimen was measured three times by using a light-emitting diode and a radiometer. Data were statistically analyzed by using univariate analysis of variance (ANOVA) followed by one-way ANOVA, Tukey honest significant difference, and Tamhane T2 tests (α = 0.05). Results: Translucent polymer infiltrated hybrid ceramic specimens exhibited significantly ( p < 0.001) lower light transmission values than high translucent polymer infiltrated hybrid ceramic and feldspathic ceramic specimens, whereas feldspathic ceramic specimens exhibited significantly ( p < 0.001) higher light transmission than translucent and high translucent polymer infiltrated hybrid ceramic specimens. The amount of light transmission significantly ( p < 0.05) decreased when the shade value decreased and the thickness increased. Conclusions: Polymer infiltrated hybrid ceramic specimens showed lower light transmission values than feldspathic ceramic specimens, and the amount of light transmission was affected by the ceramic shade and thickness.

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