scholarly journals Effect of Digital Technologies on the Marginal Accuracy of Conventional and Cantilever Co–Cr Posterior-Fixed Partial Dentures Frameworks

2021 ◽  
Vol 11 (7) ◽  
pp. 2988
Author(s):  
Celia Tobar ◽  
Verónica Rodríguez ◽  
Carlos Lopez-Suarez ◽  
Jesús Peláez ◽  
Jorge Cortés-Bretón Brinckmann ◽  
...  
Keyword(s):  
Digital Technologies ◽  
Hard Metal ◽  
Direct Metal Laser Sintering ◽  
Cobalt Chromium ◽  
Metal Ceramic ◽  
Marginal Discrepancy ◽  
Soft Metal ◽  
Manufacturing Techniques ◽  
Ceramic Restorations ◽  
To Receive

The introduction of new digital technologies represents an important advance to fabricate metal–ceramic restorations. However, few studies have evaluated the influence of these technologies on the fit of the restorations. The aim of this study was to evaluate the effect of different manufacturing techniques and pontic design on the vertical marginal fit of cobalt–-chromium (Co–Cr) posterior fixed partial dentures (FPDs) frameworks. Methods: Eighty stainless-steel dies were prepared to receive 3-unit FPDs frameworks with intermediate pontic (n = 40) and cantilever pontic (n = 40). Within each design, the specimens were randomly divided into four groups (n = 10 each) depending on the manufacturing technique: casting (CM), direct metal laser sintering (LS), soft metal milling (SM), and hard metal milling (HM). The frameworks were luted, and the vertical marginal discrepancy was assessed. Data analysis was made using Kruskal–Wallis and Mann–Whitney U tests (α = 0.05). Results: The vertical marginal discrepancy values of all FPDs were below 50 μm. The HM frameworks obtained the lowest misfit values in both designs. However, no differences were found among intermediate pontic groups or cantilevered groups. Likewise, when differences in a marginal discrepancy between both framework designs were analyzed, no differences were observed. Conclusions: The analyzed digital technologies demonstrated high precision of fit on Co–Cr frameworks and on both pontic designs.

scholarly journals MANUFACTURING TECHNIQUE OF METAL CERAMIC RESTORATION WITH IMPLANT-ABUTMENT AT GINGIVAL RESORPTION CASE

2019 ◽  
Vol 3 (1) ◽  
pp. 22
Author(s):  
Galih Paramarta ◽  
Eny Inayati
Keyword(s):  
Three Dimensional ◽  
Dental Restoration ◽  
Coating Application ◽  
Manufacturing Technique ◽  
Implant Abutment ◽  
Metal Ceramic ◽  
Manufacturing Techniques ◽  
The Aesthetic ◽  
Ceramic Restorations

Background: The low levels of patient satisfaction and confidence in the restoration of the gingival resorption results in impaired quality of life in both functional and psychosocial aspects. It is necessary to manufacture a dental restoration to restore the mastication, phonetic, and aesthetic functions associated with soft tissue repair. Manufacture of gingiva ceramic restorations which are believed to be an alternative to restore the aesthetic function and harmonization of the patient’s teeth. In terms of manufacturing techniques, this restoration has a level of difficulty in achieving a balance between “White aesthetic” and “aesthetic pink”. Objective: This study aims to provide knowledge to the reader of Manufacturing Technique of Metal Ceramic Restoration with Implant-Abutment at Gingival Resorption Case. Reviews: Gingiva ceramic restorations can be used to create esthetic implant-supported restorations when bone and gingival tissues are deficient and surgical replacement of such tissues is not possible. Dental technicians should be able to analyze the three-dimensional shapes of gingival anatomy, color, texture, smile components, the balance of the “pink aesthetic” and “white aesthetic”. Conclusion: Manufacturing Technique of Metal Ceramic Restoration with Implant-Abutment at Gingival Resorption Case including the manufacture of metal coping, oxidation, application of opaque coating, application of the first “white aesthetic” ceramics (Opaque Dentine, Dentine, Enamel and transpa on crown coping restorations), Application of opaque gingiva layer, gingival ceramics build-up "pink aesthetics”, first firing, followed by correction build-up, and second firing, and ends with the glazing process.

Marginal discrepancy of noble metal-ceramic fixed dental prosthesis frameworks fabricated by conventional and digital technologies

2018 ◽  
Vol 119 (2) ◽  
pp. 307.e1-307.e7 ◽  
Author(s):  
Ahmed Afify ◽  
Stephan Haney ◽  
Ronald Verrett ◽  
Michael Mansueto ◽  
James Cray ◽  
...  
Keyword(s):  
Noble Metal ◽  
Digital Technologies ◽  
Dental Prosthesis ◽  
Fixed Dental Prosthesis ◽  
Metal Ceramic ◽  
Marginal Discrepancy

scholarly journals Comparison of Retention and Seating of Implant-Supported Hard and Soft Metal Copings

2020 ◽  
Author(s):  
Safoura Ghodsi ◽  
Anahita Fayyazi ◽  
Maryam Ghiasi ◽  
Ahmad Rohanian ◽  
Marzieh Alikhasi
Keyword(s):  
Testing Machine ◽  
Hard Metal ◽  
Cobalt Chromium ◽  
Soft Or ◽  
Whitney Test ◽  
Mann Whitney Test ◽  
Significant Difference ◽  
Metal Group ◽  
Soft Metal ◽  
The Mean

Objectives: Implant-supported restorations are generally used for the replacement of the lost teeth. Stability against masticatory forces and proper retention are critical for optimal durability of restorations. The aim of this experimental study was to compare the retention of cobalt-chromium (Co-Cr) copings made by different techniques. Materials and Methods: Twenty-four solid abutment analogs were mounted and scanned with a desktop scanner. They were divided into two groups (n=12) and received metal copings fabricated by either soft or hard Co-Cr alloy. Soft Cera­mill Sintron Co-Cr patterns were milled and sintered. Hard Co-Cr blocks were milled in a milling machine. The copings were sandblasted, polished, adjusted, and placed on the respective abutments. The frequency of adjustments was recorded for each abutment. The copings were cemented with zinc phosphate cement and underwent tensile test by a universal testing machine. The Mann-Whitney test and t-test were used to compare the two groups (α=0.05). Results: There was no significant difference in retention of copings between the experimental groups. The mean retentive force was 559.58±115.66 N and 557.13 ±130.48 N for the soft and hard metal groups, respectively (P=0.96). Considering the non-normal distribution of adjustment frequency data, the Mann-Whitney test showed that the frequency of adjustments was significantly higher in the hard metal group than the soft metal group (9.5 versus 0.1667; P<0.001). Conclusion: Although hard metal copings required more adjustments, retention of soft and hard Co-Cr copings was not significantly different.

scholarly journals Lost-wax or laser sintering? Findings on marginal and internal adaptation of metallic copings

2021 ◽  
Vol 10 (17) ◽  
pp. e162101724429
Author(s):  
Lucas José de Azevedo-Silva ◽  
Brunna Mota Ferrairo ◽  
Renato José Berro-Filho ◽  
Fernanda Ferruzzi Lima ◽  
José Henrique Rubo
Keyword(s):  
Laser Sintering ◽  
Internal Space ◽  
Marginal Adaptation ◽  
Direct Metal Laser Sintering ◽  
Cobalt Chromium ◽  
Replica Technique ◽  
Low Viscosity ◽  
Metal Ceramic ◽  
Internal Adaptation ◽  
Ceramic Crown

Marginal and internal adaptation are parameters of crucial importance to the success of prosthetic crowns. Automatized process creates an expectative of superior or equivalent results compared to restorations manufactured ​​by conventional lost-wax technique. The purpose of this study was to evaluate the marginal adaptation and internal adaptation (cement space) of metal-ceramic crown copings produced by lost-wax (LW) and direct metal laser sintering (DMLS) techniques. An artificial lower first molar was prepared for a full crown, duplicated in plaster and scanned. Twenty metal-ceramic crown copings were fabricated in cobalt-chromium by the two techniques (n=10). The copings were filled with low viscosity silicone and seated on the prepared tooth, resulting in a replica of the internal space. The pellicle formed was embedded in heavy body silicone, sectioned and captured by means of a stereomicroscope at 50x magnification, according to replica technique (RT). Shapiro-Wilk test followed by Holm-Sidak test were used for statistical analysis (α=.05). Marginal adaptation presented no difference between LW (101.5 ± 41.6) and DMLS (86.3 ± 39.9) groups (p=0.24). Conventional LW technique showed significantly lower occlusal (p<0.008) and axial spaces (p<0.03).  Measurements of all regions showed numerically larger adaptation values than that defined during design​​ for DMLS group. Both the LW technique and the DMLS technique are within the clinically acceptable.

scholarly journals Fit of metal-ceramic crowns

2021 ◽  
Vol 21 ◽  
pp. e225136
Author(s):  
Patrícia Valéria Manozzo Kunz ◽  
Gabriela Andrade Serpa ◽  
Leonardo Fernandes da Cunha ◽  
Gisele Maria Correr ◽  
Carla Castiglia Gonzaga
Keyword(s):  
Cobalt Chromium ◽  
Manufacturing Method ◽  
Significant Difference ◽  
Metal Ceramic ◽  
Before And After ◽  
Cad Cam ◽  
Marginal Discrepancy ◽  
Ceramic Crowns ◽  
Student’S T ◽  
Internal Fit

Aim: To evaluate the influence of cobalt-chromium (Co-Cr) coping fabrication methods and ceramic application on the marginal and internal fit of metal-ceramic crowns. Methods: Co-Cr copings for metal-ceramic crowns were prepared by lost wax casting or CAD-CAM machining of sintered blocks. The fit was analyzed using the silicone replica technique at four assessment points: marginal gap (MG), axial wall (AW), axio-occlusal (AO) angle, and central occlusal (CO) wall. After the initial analysis, the copings were ceramic-veneered with the layering technique, and the fit was again determined. Data were statistically analyzed by paired and unpaired Student’s-t test (α=0.05). Results: Marginal and internal fit before ceramic application according to the coping manufacturing method showed significant differences only at CO (p < 0.001), with milled copings (137.98±16.71 μm) showing higher gap values than cast copings (112.86±8.57 μm). For cast copings, there were significant differences at MG (before 109.13±8.79 μm; after 102.78±7.18 μm) and CO (before 112.86±8.57 μm; after 104.07±10.63 μm) when comparing the fit before and after ceramic firing. For milled copings, there was significant difference only at AO (before 116.39±9.64 μm; after 108.54±9.26 μm). Conclusion: This study demonstrated that the coping fabrication method influenced the internal fit. Ceramic firing maintained or improved the fit of the metal-ceramic crowns. The marginal discrepancy of all restorations, before and after ceramic firing, can be considered clinically acceptable.

scholarly journals Marginal Discrepancy of Single Implant-Supported Metal Copings Fabricated by Various CAD/CAM and Conventional Techniques Using Different Materials

2019 ◽  
Vol 13 (04) ◽  
pp. 563-568
Author(s):  
Safoura Ghodsi ◽  
Marzieh Alikhasi ◽  
Nika Soltani
Keyword(s):  
Rapid Prototyping ◽  
Acrylic Resin ◽  
Hard Metal ◽  
Control Group ◽  
Wax Pattern ◽  
Significant Difference ◽  
Cad Cam ◽  
Marginal Discrepancy ◽  
Soft Metal ◽  
Measuring Machine

Abstract Objective Framework patterns can be formed using various materials such as wax, acrylic resin, or composite. Frameworks can be fabricated using either conventional or computerized techniques, using additive or subtractive method. This study aimed to compare the marginal adaptation of metal copings fabricated by two computerized technologies (milling and rapid prototyping) and additive conventional methods using different materials. Materials and Methods Seventy-two fixture analogs were mounted vertically in acrylic resin. One-piece abutments with 5.5 mm in length and 6 degrees of convergence were secured into the analogs. The experimental frameworks were fabricated using either subtractive CAD/CAM milling (by wax, soft or hard metal), additive rapid prototyping (by wax), or conventional pattern fabrication (by wax [control] or acrylic resin). Wax and acrylic resin patterns were casted in Ni-Cr alloy. Marginal discrepancy was measured in 12 points by video measuring machine. Statistical Analysis One-way ANOVA and posthoc tests were used to detect any significant difference among the groups at α= 0.05. Results There was a statistically significant difference among the marginal discrepancy of six groups (p = 0.018). The Tukey test indicated a significant difference between CAD/milling of soft metal and conventional wax pattern groups (p = 0.011); a significant difference was also reported between CAD/milling of wax patterns and control group (p = 0.046). Conclusions Frameworks fabricated by conventional wax-up showed the largest marginal gaps, while the marginal gap created by frameworks made of soft metal CAD/milling were the smallest. In addition, frameworks fabricated by rapid prototyping showed clinically acceptable adaptations.

Ceramic fracture in metal-ceramic restorations: the aetiology

Dental Update ◽  
2017 ◽  
Vol 44 (5) ◽  
pp. 448-456
Author(s):  
Ayesha Aslam ◽  
Danish Azeem Khan ◽  
Syed Hammad Hassan ◽  
Bilal Ahmed
Keyword(s):  
Ceramic Fracture ◽  
Metal Ceramic ◽  
Ceramic Restorations

scholarly journals Effect of recasting on the elastic modulus of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

2007 ◽  
Vol 64 (7) ◽  
pp. 469-473 ◽  
Author(s):  
Nemanja Mirkovic
Keyword(s):  
Elastic Modulus ◽  
Testing Machine ◽  
Fracture Load ◽  
Bending Test ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Nickel Chromium ◽  
Ceramic Samples ◽  
Chromium Alloys ◽  
Metal Ceramic

Background/Aim. Elastic modulus of metal-ceramic systems determines their flexural strength and prevents damages on ceramics during mastication. Recycling of basic alloys is often a clinical practice, despite the possible effects on the quality of the future metal-ceramic dentures. This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the elastic modulus of metalceramic systems in making fixed partial dentures. Methods. The research was performed as an experimental study. Six metal-ceramic samples of nickel-chromium alloy (Wiron 99) and cobalt-chromium alloy (Wirobond C) were made. Alloy residues were recycled through twelve casting generations with the addition of 50% of new alloy on the occasion of every recasting. Three- point bending test was used to determine elastic modulus, recommended by the standard ISO 9693:1999. Fracture load for damaging ceramic layer was recorded on the universal testing machine (Zwick, type 1464), with the speed of 0,05 mm/min. Results. The results of this research revealed significant differences between elasticity modules of metal-ceramic samples in every examined recycle generation. Recasting had negative effect on the elastic modulus of the examined alloys. This research showed the slight linear reduction of elastic modulus up to the 6th generation of recycling. After the 6th recycling there was a sudden fall of elastic modulus. Conclusion. Recasting of nickelchromium and cobalt-chromium alloys is not recommended because of the reduced elastic modulus of these alloys. Instead of reusing previously recasted alloys, the alloy residues should be returned to the manufacturer. .

scholarly journals CLINICAL EVALUATION OF COBALT-CHROMIUM-BASED FIXED DENTURES

2019 ◽  
Vol 15 (3) ◽  
pp. 146-151
Author(s):  
Арзу Керимова ◽  
Arzu Kerimova
Keyword(s):  
Survival Rate ◽  
Laser Sintering ◽  
High Wear Resistance ◽  
Marginal Adaptation ◽  
Direct Metal Laser Sintering ◽  
Cobalt Chromium ◽  
Proximal Caries ◽  
Direct Laser ◽  
Resistance To Deformation ◽  
Regional Adaptation

Subject. Ceramic-metal prostheses are distinguished by high wear resistance, resistance to deformation, and tight fit to the gums. However, there are relatively large differences in determining the success / survival of cobalt chromium based restorations. The article presents the results of a study of cobalt-chromium fixed dentures. Objectives — evaluate the effectiveness of cobalt-chromium fixed dentures made using the direct metal laser sintering (DMLS) technique. Material and methods. 32 patients (mean age 41.8 ± 2.46 years) were found to have 54 fixed cobalt-chromium fixed bridges made using direct laser sintering of metals. Dentures were evaluated between 6, 12, 24, 36 months according to G. Ryge criteria. The survival rate of restorations is calculated according to Kaplan-Meyer. Results. Assessment of fixed prostheses revealed the absence of criteria C and D in all 3 categories. A comparative analysis of prostheses showed no change in the period 6, 12, 24 months. After 36 months, chips that did not violate the function of the prosthesis were revealed in 5.5 % of cases, visible signs of a cleft in the category of “marginal adaptation” in 1.8 % of cases, edge discoloration of the surface in 3.7 % of cases. Radiographically, 1 patient showed signs of incipient proximal caries and periapical changes, respectively. During the study period of 6-24 months. survival rate was 1.0. The survival of the restoration over a 3-year period was 88.9 %. Conclusion. The frequency of cleavage was 5.5 %, which is comparable to the usual performance of ceramic-metal restorations. The visible signs of a cleft in the regional adaptation was 1.8 %, and the regional color mismatch was 3.7 %. 1.8 % of restoration was detected. Signs of incipient proximal caries were 1.8 %, periapical changes — 1.8 %. Survival was 88.9 %.

Sign in / Sign up

Export Citation Format

Share Document