CAD-CAM Technique Research Articles

Comparative Study of the Cad-Cam Technique vs. The Conventional Technique in the elaboration of Fixed Zirconia Prostheses

Comparative Study of the Cad-Cam Technique vs. The Conventional Technique in the elaboration of Fixed Zirconia Prostheses

Marginal gap of zirconia and lithium disilicate frameworks produced by the CAD-CAM technique through a comparator microscope in vitro analysis

Marginal gap of zirconia and lithium disilicate frameworks produced by the CAD-CAM technique through a comparator microscope in vitro analysis

Pretreatment of Hybrid Ceramics Using Alumina (Al2O3) Nanoparticles, Hydrofluoric Acid, and Holmium: YAG Laser for Optimizing Surface Roughness, Shear Bond Strength, and Topography

Evaluation of different conditioning regimes i.e., hydrofluoric acid (HFA), sandblasting (SB), selfetching ceramic primer (SECP), and Holmium: YAG (Ho: YAG) laser on the surface roughness (Ra) and shear bond strength (SBS) of hybrid ceramics. One hundred and ten hybrid ceramic discs were fabricated using the CAD-CAM technique. The discs were randomly allocated into five groups. Group 1: No Conditioning (Control), Group 2: HFA etching, Group 3: SB, Group 4: SECP and Group 5: Ho: YAG laser. The quantitative measurement of the roughness (Ra) (n = 10) from each group was conducted using a profilometer. The dual cure resin cement was bonded on the remaining fifty samples. Shear bond strength (SBS) and failure analysis were performed using a universal testing machine (UTM) and stereomicroscope. One-way analysis of variance (ANOVA) with post hoc Tukey tests was used to assess and compare the mean values of Ra and SBS among study groups. Specimens pretreated with SB displayed the maximum Ra value and bond scores. The control specimens exhibited minimum Ra and SBS. Intergroup comparison analysis indicated that HFA and Ho: YAG laser-treated groups displayed comparable outcomes of Ra and bond integrity. Sandblasting using alumina particles proved to be the most favorable pretreatment modality for hybrid ceramic surface pretreatment for attaining optimum surface roughness and shear bond strength.

The Effect of Thermo Cycling on Fracture Resistance Of Temporary Prosthesis Fabricated By CAD/CAM With Composite- Based Material

Aim: The objective of this study was to evaluate the effect of thermo cycling on fracture resistance of temporary prosthesis constriction by computer-aided design/ computer-aided manufacturing (CAD/CAM) with those of composite materials. Material and Methods: A dentoform maxillary molar tooth was prepared for full coverage crown, temporary prosthesis was constriction and divided into the following groups: CAD/CAM poly (methyl methacrylate) (PMMA) blocks, and auto- polymerizing temporary material. All specimens were subjected to thermo cycling and then fracture strength was measured by a universal testing machine. Results: The mean ± Stander deviation values for CAD CAM group before thermo cycling (560.50 ±83.581 Newton) and after thermo cycling (901.00± 311.598 Newton) were recorded statistically significant higher fracture resistance mean compared with composite fabricated interim restorations. Conclusion: Interim prosthesis constructed using CAD CAM technique showed higher fracture

Evaluation of marginal and internal fit of metal crowns made from wax patterns made by conventional technique and CAD CAM milling technique: An in vivo study

Introduction: Marginal and internal fit of a metal crown are very important for a successful metal crown prosthesis. This study will evaluate the marginal and internal fit of metal crowns produced from wax patterns that are formed by two different wax pattern fabrication procedures: conventional wax pattern fabrication and wax pattern milled using the computer-aided design and manufacture (CAD CAM) method. Objectives: To evaluate the marginal and internal fit of metal crowns over prepared tooth made from wax patterns made by conventional technique and CAD CAM technique. Methodology: A total of 21 participants with endodontically restored mandibular first molar will be selected. Two all-metal crowns will be made for each participant, thus 42 metal crowns in total will be made. These 42 metal crowns will be divided into two groups based on the method used to create wax patterns: metal crowns made using conventional hand-carved wax pattern technique (Group I, n=21) and metal crowns made using CAD CAM-milled wax pattern technique (Group II, n=21). Then, the marginal and internal fit of metal crowns from both groups will be compared. Expected results: It is expected that metal crowns made by CAD CAM milled wax pattern fabrication method will have better marginal and internal fit than those of conventional method. Conclusions: The clinical acceptability and success of the dental crown will be assessed by this study. Minimal marginal gap and better internal fit of all metal crown are key qualities.

Theoretical and practical aspects regarding the role of the working model in the workflow of porcelain fused to metal fixed restorations - Preliminary study

In dental practice, the fidelity of a model is given by the quality and type of material used, the technique by which it is made, and last but not least by the experience and skill of the dental technician. But, the emergence of CAD-CAM technology has led to a major change in the stages of making the working model, through the development of the virtual model. Thus, the purpose of this material is to perform a comparative study between several techniques for obtaining sectional working models, with or without pins, compared to the virtual model obtained by CAD-CAM technique.

Tensile Bond Strength and Retention of Three Types of Ceramic Endocrowns.

By development of adhesive dentistry and noble mechanical strength of ceramics, reconstruction of posterior teeth with partial coverage restorations such as ceramic endocrowns is possible. Different ceramics may show different mechanical properties which should be investigated. The aim of this experimental in vitro study was to compare the tensile bond strength of endocrowns made by CAD-CAM using 3 types of ceramics. In this in vitro study, 30 fresh extracted human molars were prepared to evaluate the tensile bond strength of endocrowns made by IPS e.max CAD, Vita Suprinity, and Vita Enamic blocks (n=10). The specimens were mounted and endodontically treated. Standard preparations were done with 4.5±0.5 mm intracoronal extensions into the pulp chamber and the restorations were designed and milled by CAD-CAM technique. All specimens were cemented with a dual polymerizing resin cement according to the manufacturer's instructions. The specimens were incubated for 24 hours and then thermocycled for 5000 cycles at 5-55°C and underwent the tensile strength test by universal testing machine (UTM). Shapiro-Wilk and one-way ANOVA test were used to statistically analyzed (α= 0.05). The highest tensile bond strength values were achieved in IPS e.max CAD (216.39 ±22.67N) and Vita Enamic (216.22±17.72N) followed by Vita Suprinity (211.54±20.01N). There was no significant statistical difference between retention of endocrowns made by CAD-CAM technique among ceramic blocks (p= 0.832). Within the limitation of this study, there was no significant difference between retention of endocrowns made by IPS e.max CAD, Vita Enamic, and Vita Suprinity as ceramic blocks.

Differences between the Fittings of Dental Prostheses Produced by CAD-CAM and Laser Sintering Processes.

Digital dentistry and new techniques for the dental protheses' suprastructure fabrication have undergone a great evolution in recent years, revolutionizing the quality of dental prostheses. The aim of this work is to determine whether the best horizontal marginal fit is provided by the CAD-CAM technique or by laser sintering. These values have been compared with the traditional casting technique. A total of 30 CAD-CAM models, 30 laser sintering models, and 10 casting models (as control) were fabricated. The structures realized with chromium-cobalt (CrCo) have been made by six different companies, always with the same model. Scanning electron microscopy with a high-precision image analysis system was used, and 10,000 measurements were taken for each model on the gingival (external) and palatal (internal) side. Thus, a total of 1,400,000 images were measured. It was determined that the CAD-CAM technique is the one that allows the best adjustments in the manufacturing methods studied. The laser sintering technique presents less adjustment, showing the presence of porosities and volume contraction defects due to solidification processes and heterogeneities in the chemical composition (coring). The technique with the worst adjustments is the casting technique, containing numerous defects in the suprastructure. The statistical analysis of results reflected the presence of statistically significant gap differences between the three manufacturing methods analyzed (p < 0.05), with the samples manufactured by CAD-CAM and by traditional casting processes being the ones that showed lower and higher values, respectively. No statistically significant differences in fit were observed between the palatal and gingival fit values, regardless of the manufacturing method used. No statistically significant differences in adjustment between the different manufacturing centers were found, regardless of the process used.

Marginal discrepancy and fracture load of thermomechanically fatigued crowns fabricated with different CAD-CAM techniques.

To assess the effect of CAD-CAM technique (monolithic, CAD-on, or CAD-on cemented) and thermomechanical fatigue on the marginal discrepancy and fracture load of ceramic crowns. A total of 90 brass master dies were fabricated to investigate marginal adaptation and fracture load. A mandibular first molar crown's median measurements were loaded into CAD software and divided into 2 crown design groups: Monolithic (M)(IPS e.max zirCAD)(n= 30) or CAD-on core (IPS e.max zirCAD) and lithium disilicate veneer (IPS e.max CAD) (n= 60). The crowns and cores were milled, seated on their respective dies, and marginal discrepancy values were measured by using microcomputed tomography. After veneers were milled, the cores in the veneer groups were divided into 2 groups; veneers bonded with fusion glass-ceramic (IPS e.max CAD Crystal) in CAD-on group (CO) and CAD-on cemented group (CO-C) where veneers were cemented (RelyX U200) onto cores (CO-C). The marginal discrepancy measurements were remade and the crowns were subjected to thermomechanical fatigue (TMF) by using a chewing simulator and thermocycling (5-55°C, 1,200,000 cycles). Marginal discrepancy measurements were repeated and the crowns were subjected to fracture load test by using a universal test device. Data were analyzed statistically by analysis of variance (ANOVA) and Tukey's honestly significant difference test (α= 0.05). All crown groups had similar marginal discrepancy before veneering. Veneering and cementation on die increased the marginal discrepancy of crowns in cemented CAD-on group. Thermomechanical fatigue increased the marginal discrepancy of both CAD-on groups. Monolithic crown group had the lowest marginal discrepancy after thermomechanical fatigue (p < 0.001), and the highest fracture load (p < 0.001) CONCLUSIONS: Fabrication technique affected the marginal fit and fracture load of CAD-CAM crowns after thermomechanical fatigue. All crowns survived the thermomechanical fatigue test without dislodgement or fracture. Monolithic crowns had the best fit and highest fracture load after fatigue testing. The CAD-on systems had similar marginal discrepancies, and static loading reproduced veneer chipping.

Design And Digital Fabrication Technique of a Hybrid Framework - A Literature Review

Hybrid dentures consist of one of the most popular options in the fixed restoration of the edentulous arch. For a successful and durable prosthesis it is of utmost importance to pay good attention to the design and fabrication of such implant frameworks. Conventionally the framework was fabricated using traditional metal casting. However, with the advent of digital dentistry CAD CAM frameworks have become popular and their fabrication much easier and efficient.With a focus on design of implant frameworks and the digital fabrication process of hybrid dentures, the goal of this study was to summarise the pertinent literature in this area.In conclusion, hybrid dentures seem like a viable treatment option when designed correctly and CAD CAM technique seems like a popular and efficient technique to do so.

Marginal Misfit of 3D-Printed (Selective Laser Sintered), CAD-CAM and Lost Wax Technique Cobalt Chromium Copings with Shoulder and Chamfer Finish Lines: An In-Vitro Study.

Background and Objectives: The aim was to compare the Misfit of 3D-Printed, Selective laser melting (SLM), milled (Computer aided design-Computer aided manufacture CAD-CAM) and Lost wax technique (LWT) fabricated Cobalt chromium (CoCr) alloy copings on shoulder (SH), radial shoulder (R-SH) and chamfer (CH) finish line configuration. Materials and Methods: Ninety resin, second maxillary premolar teeth were prepared for metal-ceramic crowns, equally divided into (n = 30) SH, R-SH and CH margin preparations. For each preparation design (SH, R-SH and CH), CoCr copings were prepared using SLM, CAD-CAM and LWT. This resulted in nine study groups with 10 CoCr copings each. The marginal misfit of specimens was assessed with a high-resolution digital microscope. Misfit was evaluated in vertical and horizontal dimensions in μm. Data were analyzed using ANOVA and a post hoc multiple comparisons test. Results: For vertical misfit, the highest was observed in SLM samples with chamfer margin (167.96 ± 24.1), and the least was shown by CAD-CAM samples with radial shoulder (58.8 ± 12.53). CAD-CAM and shoulder margins showed the least vertical misfit. For horizontal misfit, the maximum was observed in SLM samples with shoulder margin (137.94 ± 37.85) and the least by LWT samples with chamfer (89.38 ± 14.81). Chamfer margins and LWT samples showed the least horizontal misfit among the group samples. Fabrication technique and finish line design play a critical role in reducing the marginal misfit of CoCr copings. Conclusions: For vertical misfit, SLM copings showed poor outcomes compared to CAD-CAM specimens, however comparable outcomes to Cast specimens. SLM copings showed comparable horizontal misfit outcomes to CAD-CAM specimens and low misfit compared to Cast copings, respectively. Vertical misfit was low with shoulder margins, and horizontal misfit was better with chamfer marginal configuration.

Effect of Vent Hole and Cement Type on Fracture Resistance of CAD-CAM Monolithic Zirconia Crowns.

To assess the fracture resistance of monolithic zirconia crowns cemented with different types of cement on cement-retained implant abutments. Forty implant analogs were positioned in acrylic resin blocks, and cement-retained straight implant abutments were fastened to the analogs. Crowns were designed with/without occlusal vent holes and produced from monolithic zirconia blocks by the CAD-CAM technique. The two crown types were divided into two groups and cemented with resin and zinc-polycarboxylate cement under 5 kg weight. A universal testing machine applied compressive forces to the crowns until fracture. Fracture resistance values were analyzed using two-way ANOVA and the independent samples t-test with statistical significance set at p < 0.05. According to the two-way ANOVA results, although the crown design did not have a significant effect on fracture resistance (1417.65 ± 337.39 N, 1565.16 ± 517.12 N; crowns with and without vent holes, respectively), the main effect of the cement variable on the fracture resistance was significant. Zinc-polycarboxylate cement (1680.1 ± 375.23 N) showed higher fracture resistance than resin cement (1302.71 ± 420.64 N) in the crowns designed with vent holes (p < 0.005). The use of cement-retained implant-supported monolithic zirconia crowns with an occlusal vent hole is safe, and zinc-polycarboxylate cement use may be an appropriate choice for cementation of these crowns.

The cumulative effect of error in the digital workflow for complete-arch implant-supported frameworks: An in vitro study.

To investigate the error accumulation and distribution through various stages of the digital workflow for complete-arch implant-supported framework fabrication. A resin model of edentulous maxilla with 6 dental implants was scanned using an intraoral scanner for 10 times (Complete-digital group). Ten conventional gypsum casts were made and digitized by a laboratory scanner (Analogue-digital group). Five implant frameworks were designed and milled using CAD-CAM technique for each workflow. Inter-implant distances and angles of the resin model (reference) and frameworks were measured by a coordinate measuring machine, while the scans and virtual frameworks were examined by an inspection software. Effect of type of workflow and the individual stage on the accuracy of the frameworks were analysed by Two-way ANOVA. The expanded uncertainty of both workflows was ~150 μm and ~ 0.8°. The accuracy of the CAD stage was the highest. In the complete-digital workflow, the greatest distortion was found in the data acquisition stage, while in the analogue-digital workflow, it was found in the CAM stage. Compared with the analogue-digital group, the complete-digital group showed a significant higher precision in the first quadrant, but lower trueness in the second quadrant in data acquisition, and a significantly lower precision in the second quadrant at the CAD stage. Linear distortions of the complete-digital and analogue-digital workflows were clinically acceptable, while angular distortions were not. Distortions were generally derived from data acquisition and CAM stage. The CAD precision depended on the distortions derived from data acquisition. The complete-digital workflow was not as accurate as the analogue-digital in complete-arch implant rehabilitation.

CAD-CAM technique based digital diagnosis and fixed partial denture treatment on maxillary congenital missing teeth with skeletal class III tendency patient: A case report

CAD-CAM technique based digital diagnosis and fixed partial denture treatment on maxillary congenital missing teeth with skeletal class III tendency patient: A case report

Fabrication of Metal-Reinforced Complete Dentures Using the CAD-CAM Technique

The digital manufacture of complete dentures would greatly simplify the workflow; however, the metal-reinforced complete dentures production method has not been well established. This article describes a technique of fabricating metal-reinforced complete dentures in a milling machine using the geometry guide, a negative impression of the occlusal surface of the metal-reinforced complete denture designed using the computer-aided design software. The geometry guide supports and stabilizes the artificial teeth and metal framework in the correct position in the surrounding resin. Fabrication of metal-reinforced dental prosthesis using the digital technique is possible with this method.

Degenerative joint disease: from a conservative to a minimally invasive approach – clinical case

Introduction Degenerative joint disease is a subtype of temporomandibular derangements. It can be characterised by possible progressive cartilage degradation, subchondral bone remodelling, and chronic inflammation in the synovial tissue [1]. For the treatment of temporomandibular disorders, minimally invasive techniques, such as viscosupplementation, should normally be applied after more conservative techniques [2]. Materials and methods Female patient, 22 years old, with probable disc displacement with occasional blocking and bilateral degenerative joint disease. Before starting any treatment, the patient was asked to sign an informed consent. Diagnosis was made through the symptom questionnaire and clinical exam integrated on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) protocol [3] along with imagiological exams. Definitive diagnosis was disc displacement with occasional blocking, bilateral degenerative joint disease, bilateral arthralgia, masseter myalgia and bruxism self-report. On a first approach we did behavioural and cognitive therapy, viscosupplementation with hyaluronic acid 1.5% of high molecular weight (Syaloset 2000®), anterior repositioning splint drawn and printed with CAD-CAM technique (Exocad dentalCAD®) and physiotherapy exercises, like manual therapy for muscular relaxation and condylar distraction, as well as, at-home physiotherapy exercises. For evaluate if there were any improvement on function, comfort and quality of life the OHIP-14 questionnaire [4] was applied before and after the viscosupplementation and again, after 1 month of the occlusal splint use. The same thing was done with the DC/TMD protocol. Results According to the OHIP-14 questionnaire, before treatment the patient mainly referred the articular pain that she felt during mastication. After the first viscosupplementation session and the new OHIP-14 questionnaire application, the patient referred substantial improvements on the pain during function. However, she expressed her concerns with the expectations of the treatment. After 1 month of occlusal splint use her concerns were gone and pain during function did not come back. Discussion and conclusions Disc displacements should be carefully evaluated before the prescription of an anterior repositioning splint. However, in cases like this, they are indicated [5]. In this case, viscosupplementation was used in the beginning of treatment to allow the TMJ to recover function without limitations and restoring a dynamic lubrification. Treatment of TMJ disfunctions should be conservative and always multidisciplinary.

Comparison of the Fit Accuracy of Hybrid Ceramic Prostheses Generated By Three CAD-CAM Systems.

Background: Marginal and internal fit are believed to be one of the most important guideline in the assessment of ceramic restorations and are one of the most remarkable requirement for the long-term performance of fixed dental prostheses. PURPOSE: Was to evaluate the influence of different CAD-CAM systems on the marginal and internal adaptation of hybrid ceramic restorations. Materials and Methods: Lower right six of a typodont resin cast with a 1.0 mm circumferential chamfer finish line, an occlusal reduction of 2.0 mm, and an average of 10-12° convergence angle was prepared. This master die was duplicated to thirty acrylic resin dies milled from PMMA discs using CAD-CAM technique. Vita Enamic monolithic crowns were manufactured using three different CAD-CAM systems Ceramill, Zirkonzahn and CEREC InLab systems (n=10). Replica technique procedure was used to assess marginal and internal fit of the fabricated prostheses by measuring the thickness of light body impression material between the master die and the restoration at five points using digital microscope. Results: Measurements were collected for each group and appropriate statistical analysis was carried out. Conclusion: CEREC system showed relatively lower marginal and internal discrepancy in a comparison with the other systems. Therefore, there is a significant difference among the three systems.

A case of digital maxillary complete denture and mandibular implant overdenture fabricated by CAD-CAM technique

A case of digital maxillary complete denture and mandibular implant overdenture fabricated by CAD-CAM technique

Comparison between Additive and Subtractive CAD-CAM Technique to Produce Orthognathic Surgical Splints: A Personalized Approach.

The present study aimed to evaluate the accuracy of digitally designed surgical splints generated with milling technology (material subtractive procedure) and with 3D printing technology (material additive procedure) through a customized approach in the planning of surgical orthognathic splints. Cone beam computed tomography (CBCT) examinations and scanned dental models of 10 subjects who had required surgical treatment of skeletal malocclusion were included. Simulation of the orthognathic surgery was performed according to dento-skeletal and aesthetic characteristics of the subjects and the visual treatment objective (VTO), using Dolphin3D software (Dolphin Imaging, version 11.0, Chatsworth, CA, USA). Afterward, the Appliance Designer software (3Shape A/S, Copenhagen, Denmark) was used to digitally design the surgical splints that were generated twice using laser stereolithography technology (DWS 0.29D, DWS, Vicenza, Italy) and milling technology (Sirona inLab MC X5). Finally, each physical splint was digitalized using a desktop scanner (D500 3D, 3Shape A/S, Copenhagen, Denmark) in order to perform deviation analysis using the original project as a reference. The relative percentage of matching (trueness) was calculated (Geomagic Control X software (3D Systems, version 2018.1.1, 3D Systems, Rock Hill, SC, USA). An Independent Student’s t-test was used to statistically analyze the data. The milled splints showed a lower value of root to mean square (RMS) relative to the original project (0.20 mm ± 0.018) compared to the prototyped splints (0.31 ± 0.021) (p < 0.001). According to the present findings, surgical splints generated with milling technology present higher trueness compared with 3D printing technology.

Fitness evaluation of mandibular kennedy class I BioHPP Poly-Ether-Ether ketone removable partial denture fabricated by various techniques

Fitness evaluation of mandibular kennedy class I BioHPP Poly-Ether-Ether ketone removable partial denture fabricated by various techniques - APRD- Print ISSN No: - 2581-4796 Online ISSN No:- 2581-480X Article DOI No:- 10.18231/j.aprd.2019.023, IP Annals of Prosthodontics and Restorative Dentistry-IP Ann Prosthodont Res