1
|
Abduo J, Ho G, Centorame A, Chohan S, Park C, Abdouni R, Le P, Ngo C. Marginal Accuracy of Monolithic and Veneered Zirconia Crowns Fabricated by Conventional and Digital Workflows. J Prosthodont 2023; 32:706-713. [PMID: 36321644 DOI: 10.1111/jopr.13618] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/21/2022] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To compare the marginal accuracy of zirconia crowns fabricated by different workflows (conventional and digital) and designs (monolithic and veneered). MATERIALS AND METHODS A prepared maxillary first molar was used for the study. Four workflow combinations were evaluated: (1) intraoral scanning and monolithic zirconia (IOS-M), (2) intraoral scanning and veneered zirconia (IOS-V), (3) conventional impression and monolithic zirconia (IMP-M), and (4) conventional impression and veneered zirconia (IMP-V). All of the specimens had similar designs. The veneered groups had a buccal cutback for esthetic veneer application. A total of 10 crowns were produced in each workflow. The vertical and horizontal marginal accuracies were measured with a traveling microscope. Depending on the normality of the data, one-way analysis of variance test or Kruskal-Wallis test were applied to evaluate the differences among the groups (α = 0.05). RESULTS The most superior vertical marginal accuracy was observed for IOS-V (mean = 22.5 μm; SD = 6.7 μm), followed by IMP-V (mean = 23.9 μm; SD = 7.8 μm), IOS-M (mean = 28.7 μm; SD = 10.3 μm), and IMP-M (mean = 39.8 μm; SD = 22.0 μm), respectively (p < 0.001). The IOS-M had the greatest mean horizontal discrepancies (mean = 23.9 μm; SD = 4.3 μm) followed by IMP-M (mean = 21.3 μm; SD = 5.7 μm), IMP-V (mean = 19.2 μm; SD = 5.3 μm) and IOS-V (mean = 17.6 μm; SD = 5.7 μm) (p < 0.001). CONCLUSIONS Monolithic zirconia crowns fabricated digitally had superior marginal accuracy than monolithic zirconia crowns fabricated conventionally. Esthetic buccal veneering of predominantly monolithic zirconia copings improved the vertical and horizontal marginal accuracies.
Collapse
Affiliation(s)
- Jaafar Abduo
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Grace Ho
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Alannah Centorame
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Simran Chohan
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Clara Park
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Ramiz Abdouni
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Phillip Le
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Christopher Ngo
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| |
Collapse
|
2
|
Nawafleh N, Hatamleh M, Janzeer Y, Alrahlah A, Alahadal K. Marginal Discrepancy of Five Contemporary Dental Ceramics for Anterior Restorations. Eur J Dent 2023; 17:1114-1119. [PMID: 36599451 PMCID: PMC10756837 DOI: 10.1055/s-0042-1758787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVES This study aimed to compare marginal accuracy of five contemporary all-ceramic crowns indicated for anterior restorations. MATERIALS AND METHODS A master die of maxillary central incisor was prepared for all-ceramic crown and duplicated to produce 50 replicas of epoxy resin material. Five ceramic materials were used to mill the crowns (n = 10). All crowns were manufactured following the same digital workflow; same master die, scanning unit and design software, and the recommended manufacturing protocol. Final seating of crown was secured by a small droplet of temporary cement on its incisal edge. Marginal accuracy was evaluated by scanning electronic microscope with a magnification of 300 × . Vertical marginal gap was measured for each crown at predefined four points. STATISTICAL ANALYSIS One-way analysis of variance was used to test differences between groups and Tukey test was used for multiple comparisons between group combinations. A level of significance at 95% was set for all statistics. RESULTS The highest mean marginal gap and mean maximum gap calculated were for the e.max CAD crowns (49.2 µm, 87.6 µm), while the lowest values were for the Cercon xt crowns (10.2 µm, 21.7 µm). The mean marginal gap and the mean maximum gap of the e.max CAD crowns were statistically significantly greater than those of all other groups (p < 0.05). However, the differences between all other combinations were insignificant (p > 0.05). CONCLUSION Marginal accuracy of lithium disilicate crowns is clinically acceptable. Zirconia and zirconia-reinforced lithium silicate materials can produce a greater level of marginal accuracy compared to lithium disilicate.
Collapse
Affiliation(s)
- Noor Nawafleh
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Muhanad Hatamleh
- Department of Applied Medical Sciences, Luminus Technical University College, Amman, Jordan
| | - Yasmeen Janzeer
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Ali Alrahlah
- Engineer Abdullah Bugshan Research Chair for Dental and Oral Rehabilitation, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
- Restorative Dental Sciences Department, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Khold Alahadal
- Restorative Dental Sciences Department, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| |
Collapse
|
3
|
Raghav PS, Abirami S, Gupta A, Khan Yusufi FN, Afroz S. Effect of different impression techniques on marginal fit of restoration - An In Vitro study. Indian J Dent Res 2023; 34:294-299. [PMID: 38197350 DOI: 10.4103/ijdr.ijdr_991_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024] Open
Abstract
Introduction Impression making is one such important clinical step, which is critical in the accurate fitting of resulting prostheses. Impression making itself depends on the type of material and the impression technique used to record the details. Various combinations of material and the technique have been described in the literature. Aim To evaluate the effect of three different impression techniques on the marginal fit of computer-aided designed/computer-aided manufactured (CAD/CAM) single unit composite fixed dental prostheses (FDP), different consistencies of addition silicone impression material and different tray design were utilized. Method Impression of prepared tooth on typodont was made using Matrix impression system, two-step putty wash technique, and individual tooth tray technique. Prosthesis was fabricated using CAD/CAM technology and marginal accuracy was evaluated using scanning electron microscopy (SEM). Result In the present study, the matrix impression system resulted in less microgap in both mid-buccal and mid-mesial region, whereas putty wash technique showed very high standard deviation in the interproximal region. Conclusion Matrix impression system had the best results at both mid-buccal and mid-mesial position with least marginal discrepancy. Clinical Implication The findings of this study could be used by clinicians to help them choose the viscosity of polyvinylsiloxane material and impression techniques for FDP that will result in high-accuracy impressions and well-fitting prostheses.
Collapse
Affiliation(s)
- Priyanka S Raghav
- Department of Prosthodontics/Dental Materials, Dr. Z. A. Dental College, Aligarh, Uttar Pradesh, India
| | - S Abirami
- Department of Prosthodontics/Dental Materials, Dr. Z. A. Dental College, Aligarh, Uttar Pradesh, India
| | - Abhinav Gupta
- Department of Prosthodontics/Dental Materials, Dr. Z. A. Dental College, Aligarh, Uttar Pradesh, India
| | - Faiz Noor Khan Yusufi
- Department of Statistics and Operations Research, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Shaista Afroz
- Department of Prosthodontics/Dental Materials, Dr. Z. A. Dental College, Aligarh, Uttar Pradesh, India
| |
Collapse
|
4
|
A B, M S, B M. Comparative Evaluation of Distortion in Wax Patterns Fabricated Using Conventional and Electrical Heat Sources: An In Vitro Study. Cureus 2023; 15:e41235. [PMID: 37529510 PMCID: PMC10388666 DOI: 10.7759/cureus.41235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2023] [Indexed: 08/03/2023] Open
Abstract
Introduction Tooth loss significantly impacts individuals' functional capabilities and quality of life. Fixed partial dentures have been a reliable treatment method for tooth replacement, with their fabrication often involving waxes. Waxes play a crucial role in creating a wax pattern in dental restoration; in particular, inlay waxes play a role in the shape, size, and contour of the restorations. However, these waxes have inherent disadvantages, including a high thermal expansion coefficient and propensity to warp or distort over time. This study aimed to compare wax patterns derived from two heat sources, an electric heat source and a conventional flame, to enhance their marginal accuracy and dimensional stability. Methods This study used an abutment resembling a prepared maxillary right central incisor designed via computer-aided design software and milled from zirconia. Inlay wax was melted using either an electrically heated spatula or a conventional flame, poured into a metal sleeve or a cuboidal mold, and allowed to cool to room temperature. The wax patterns were stored at room temperature for one hour and 24 hours. Subsequently, linear and volumetric measurements were taken to assess the shrinkage of the wax patterns. Results Patterns fabricated using the electric heat source showed less shrinkage at both time points for linear shrinkage and at one hour for volumetric shrinkage than those made using the conventional flame. However, by the 24th hour, patterns made with the electric heat source showed more volumetric shrinkage than those made with the conventional heat source. Significant shrinkage was observed between one hour and 24 hours for both heat sources, suggesting that wax patterns should be invested immediately after fabrication for maximum precision. Conclusions The results suggest that electric heating may be a viable alternative to conventional flame for minimizing discrepancies in wax patterns, particularly in the initial stages of wax pattern fabrication. However, prolonged use may lead to greater volumetric shrinkage with electric heating. These findings point to the potential of electric heating as an alternative to conventional flame in dental restorations, although further research is needed to validate and expand upon these findings.
Collapse
Affiliation(s)
| | - Saravanan M
- Prosthodontics, SRM Dental College, Chennai, IND
| | - Muthukumar B
- Prosthodontics, SRM Dental College, Chennai, IND
| |
Collapse
|
5
|
Ferrini F, Paolone G, Di Domenico GL, Pagani N, Gherlone EF. SEM Evaluation of the Marginal Accuracy of Zirconia, Lithium Disilicate, and Composite Single Crowns Created by CAD/CAM Method: Comparative Analysis of Different Materials. Materials (Basel) 2023; 16:2413. [PMID: 36984293 PMCID: PMC10058296 DOI: 10.3390/ma16062413] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/12/2023] [Accepted: 03/15/2023] [Indexed: 06/18/2023]
Abstract
(1) Background: The objective of this in vitro study is to evaluate the marginal accuracy of crowns created by CAD/CAM. (2) Methods: A customized chrome-cobalt (Cr-Co) implant abutment simulating a maxillary right first molar was fixed in a hemi-maxillary stone model and scanned. In total, 27 crowns were fabricated, including 9 lithium disilicate crowns, 9 composite crowns, and 9 zirconia crowns. The measurements were determined by scanning electron microscopy. Descriptive analysis was performed using the mean and standard deviation, while the Kruskal-Wallis test was performed to determine whether the marginal discrepancies were significantly different between each group (p < 0.05). (3) Results: The lowest marginal gap value was reported for zirconia (21.45 ± 12.58 µm), followed by composite (44.7 ± 24.96 µm) and lithium disilicate (62.28 ± 51.8 µm). The Kruskal-Wallis tests revealed a statistically significant difference (p-value < 0.05) in the mean marginal gaps between different materials. (4) Conclusions: The proposed digital workflow can be a viable alternative for fixed prosthetic rehabilitations. The best performance in terms of marginal gap was achieved by zirconia crowns, but all three materials demonstrate marginal closure below the clinically accepted threshold value (120 µm). Clinical significance: although significant differences were reported, the investigated CAD/CAM materials showed clinically acceptable marginal gaps.
Collapse
Affiliation(s)
- Francesco Ferrini
- Dental School, IRCCS San Raffaele Hospital, Vita-Salute San Raffaele University, 20132 Milan, Italy
| | - Gaetano Paolone
- Dental School, IRCCS San Raffaele Hospital, Vita-Salute San Raffaele University, 20132 Milan, Italy
| | | | - Nicolò Pagani
- Dental School, IRCCS San Raffaele Hospital, Vita-Salute San Raffaele University, 20132 Milan, Italy
| | - Enrico Felice Gherlone
- Dental School, IRCCS San Raffaele Hospital, Vita-Salute San Raffaele University, 20132 Milan, Italy
| |
Collapse
|
6
|
Arora O, Ahmed N, Maiti S. Comparison of the marginal accuracy of metal copings fabricated by 3D-printed resin and milled polymethyl methacrylate - An in vitro study. J Adv Pharm Technol Res 2022; 13:S238-S242. [PMID: 36643161 PMCID: PMC9836134 DOI: 10.4103/japtr.japtr_210_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 08/07/2022] [Accepted: 08/08/2022] [Indexed: 01/17/2023] Open
Abstract
Computer-aided design/computer-aided manufacturing (CAD/CAM) systems have gained popularity over the traditional laboratory procedures in dentistry. In the conventional metal casting technique by burnout of a pattern, instead of using a wax pattern (which has several disadvantages), milled polymethyl methacrylate (PMMA) and 3D-printed resin patterns can also be used. The objective of the study was to assess and compare the marginal accuracy of single-crown cobalt-chromium (Co-Cr) metal copings fabricated using milled PMMA and 3D-printed resin patterns. Digital designing was done for metal coping on a prepared typodont mandibular molar using 3Shape Dental Design software. Standard Tessellation Language document of CAD design was used to fabricate 3D-printed resin patterns (Sprintray 3D printer) and milled PMMA patterns (CAD/CAM milling machine CoriTEC). A total of ten Co-Cr copings were casted, of which five belonged to Group A: 3D-printed resin and the other five to Group B: milled PMMA. The copings were assessed for marginal fit at eight different points using a stereomicroscope. Statistical analysis was done using an independent t-test. The t-test revealed a significant difference between the mean marginal gap values of the two groups, with the marginal gap values for the 3D-printed resin group (82.21 ± 15.26 μm) being lesser than that of the milled PMMA group (106.75 ± 12.76 μm). The marginal accuracy of copings fabricated using 3D-printed resin patterns was superior to that of copings fabricated from milled PMMA patterns.
Collapse
Affiliation(s)
- Ojasvini Arora
- Department of Prosthodontics and Implantology, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India
| | - Nabeel Ahmed
- Department of Prosthodontics and Implantology, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India
| | - Subhabrata Maiti
- Department of Prosthodontics and Implantology, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India,Address for correspondence: Dr. Subhabrata Maiti, Department of Prosthodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai - 600 077, Tamil Nadu, India. E-mail:
| |
Collapse
|
7
|
Ferrini F, Sannino G, Chiola C, Capparé P, Gastaldi G, Gherlone EF. Influence of Intra-Oral Scanner (I.O.S.) on The Marginal Accuracy of CAD/CAM Single Crowns. Int J Environ Res Public Health 2019; 16:ijerph16040544. [PMID: 30769768 PMCID: PMC6406818 DOI: 10.3390/ijerph16040544] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 11/16/2022]
Abstract
The aim of this in vitro study was to compare the quality of digital workflows generated by different scanners (Intra-oral digital scanners (I.O.S.s)) focusing on marginal fit analysis. A customized chrome-cobalt (Cr-Co) implant abutment simulating a maxillary right first molar was fixed in hemi-maxillary stone model and scanned by eight different I.O.S.s: Omnicam® (Denstply Sirona, Verona, Italy) CS3500®, CS3600®, (Carestream Dental, Atlanta, GA, USA), True Definition Scanner® (3M, St. Paul, MN, USA), DWIO® (Dental Wings, Montreal, Quebec, Canada), PlanScan® (Planmeca Oy, Helsinki, Finland), 3D PROGRESS Plus® (MHT, Verona, Italy), TRIOS 3® (3Shape, Copenhagen, Denmark). Nine scans were performed by each tested I.O.S. and 72 copings were designed using a dental computer-assisted-design/computer-assisted-manufacturing (CAD/CAM) software (exocad GmbH, Darmstadt, Germany). According to CAD data, zirconium dioxide (ZrO₂) copings were digitally milled (Roland DWX-50, Irvine, CA, USA). Scanning electron microscope (SEM) direct vision allowed for marginal gap measurements in eight points for each specimen. Descriptive analysis was performed using mean, standard deviation, and median, while the Kruskal⁻Wallis test was performed to determine whether the marginal discrepancies were significantly different between each group (significance level p < 0.05). The overall mean marginal gap value and standard deviation were 53.45 ± 30.52 μm. The minimum mean value (40.04 ± 18.90 μm) was recorded by PlanScan®, then 3D PROGRESS Plus® (40.20 ± 21.91 μm), True Definition Scanner® (40.82 ± 26.19 μm), CS3500® (54.82 ± 28.86 μm) CS3600® (59,67 ± 28.72 μm), Omnicam® (61.57 ± 38.59 μm), DWIO® (62.49 ± 31.54 μm), while the maximum mean value (67.95 ± 30.41 μm) was recorded by TRIOS 3®. The Kruskal⁻Wallis tests revealed a statistically significant difference (p-value < 0.5) in the mean marginal gaps between copings produced by 3D PROGRESS Plus®, PlanScan, True Definition Scanner, and the other evaluated I.O.S.s. The use of an I.O.S. for digital impressions may be a viable alternative to analog techniques. Although in this in vitro study PlanScan®, 3D PROGRESS Plus® and True Definition Scanner® may have showed the best performances, all I.O.S.s tested could provide clinically encouraging results especially in terms of marginal accuracy, since mean marginal gap values were all within the clinically acceptable threshold of 120 μm.
Collapse
Affiliation(s)
- Francesco Ferrini
- Department of Dentistry, IRCCS San Raffaele Hospital and Dental School, Vita Salute University, 20123 Milan, Italy.
| | - Gianpaolo Sannino
- Department of Dentistry, IRCCS San Raffaele Hospital and Dental School, Vita Salute University, 20123 Milan, Italy.
| | - Carlo Chiola
- Dental School, Vita Salute University, 20123 Milan, Italy.
| | - Paolo Capparé
- Department of Dentistry, IRCCS San Raffaele Hospital and Dental School, Vita Salute University, 20123 Milan, Italy.
| | - Giorgio Gastaldi
- Department of Dentistry, IRCCS San Raffaele Hospital and Dental School, Vita Salute University, 20123 Milan, Italy.
- San Rocco Clinical Institute, 25050 Brescia, Italy.
| | - Enrico Felice Gherlone
- Department of Dentistry, IRCCS San Raffaele Hospital and Dental School, Vita Salute University, 20123 Milan, Italy.
| |
Collapse
|
8
|
Kim MJ, Choi YJ, Kim SK, Heo SJ, Koak JY. Marginal Accuracy and Internal Fit of 3-D Printing Laser-Sintered Co-Cr Alloy Copings. Materials (Basel) 2017; 10:E93. [PMID: 28772451 DOI: 10.3390/ma10010093] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 01/17/2017] [Accepted: 01/18/2017] [Indexed: 12/04/2022]
Abstract
Laser sintered technology has been introduced for clinical use and can be utilized more widely, accompanied by the digitalization of dentistry and the development of direct oral scanning devices. This study was performed with the aim of comparing the marginal accuracy and internal fit of Co-Cr alloy copings fabricated by casting, CAD/CAM (Computer-aided design/Computer-assisted manufacture) milled, and 3-D laser sintered techniques. A total of 36 Co-Cr alloy crown-copings were fabricated from an implant abutment. The marginal and internal fit were evaluated by measuring the weight of the silicone material, the vertical marginal discrepancy using a microscope, and the internal gap in the sectioned specimens. The data were statistically analyzed by One-way ANOVA (analysis of variance), a Scheffe’s test, and Pearson’s correlation at the significance level of p = 0.05, using statistics software. The silicone weight was significantly low in the casting group. The 3-D laser sintered group showed the highest vertical discrepancy, and marginal-, occlusal-, and average- internal gaps (p < 0.05). The CAD/CAM milled group revealed a significantly high axial internal gap. There are moderate correlations between the vertical marginal discrepancy and the internal gap variables (r = 0.654), except for the silicone weight. In this study, the 3-D laser sintered group achieved clinically acceptable marginal accuracy and internal fit.
Collapse
|
9
|
Amin BM, Aras MA, Chitre V. A comparative evaluation of the marginal accuracy of crowns fabricated from four commercially available provisional materials: An in vitro study. Contemp Clin Dent 2015; 6:161-5. [PMID: 26097348 PMCID: PMC4456735 DOI: 10.4103/0976-237x.156035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Purpose: The purpose of this in vitro study was to evaluate and compare the primary marginal accuracy of four commercially available provisional materials (Protemp 4, Luxatemp Star, Visalys Temp and DPI tooth moulding powder and liquid) at 2 time intervals (10 and 30 min). Materials and Methods: A customized stainless steel master model containing two interchangeable dies was used for fabrication of provisional crowns. Forty crowns (n = 10) were fabricated, and each crown was evaluated under a stereomicroscope. Vertical marginal discrepancies were noted and compared at 10 min since the start of mixing and then at 30 min. Observations and Results: Protemp 4 showed the least vertical marginal discrepancy (71.59 μ), followed by Luxatemp Star (91.93 μ) at 10 min. DPI showed a marginal discrepancy of 95.94 μ while Visalys Temp crowns had vertical marginal discrepancy of 106.81 μ. There was a significant difference in the marginal discrepancy values of Protemp 4 and Visalys Temp. At 30 min, there was a significant difference between the marginal discrepancy of Protemp 4 crowns (83.11 μ) and Visalys Temp crowns (128.97 μ) and between Protemp 4 and DPI (118.88 μ). No significant differences were observed between Protemp 4 and Luxatemp Star. Conclusion: The vertical marginal discrepancy of temporary crowns fabricated from the four commercially available provisional materials ranged from 71 to 106 μ immediately after fabrication (at 10 min from the start of mix) to 83–128 μ (30 min from the start of mix). The time elapsed after mixing had a significant influence on the marginal accuracy of the crowns.
Collapse
Affiliation(s)
| | - Meena Ajay Aras
- Department of Prosthodontics, Goa Dental College, Bambolim, Goa, India
| | - Vidya Chitre
- Department of Prosthodontics, Goa Dental College, Bambolim, Goa, India
| |
Collapse
|
10
|
Alex D, Shetty YB, Miranda GA, Prabhu MB, Karkera R. Marginal accuracy of nickel chromium copings fabricated by conventional and accelerated casting procedures, produced with ringless and metal ring investment procedures: A comparative in vitro study. J Indian Prosthodont Soc 2015; 15:58-64. [PMID: 26929488 PMCID: PMC4762291 DOI: 10.4103/0972-4052.155043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Conventional investing and casting techniques are time-consuming and usually requires 2-4 h for completion. Accelerated nonstandard, casting techniques have been reported to achieve similar quality results in significantly less time, namely, in 30-40 min. During casting, it is essential to achieve compensation for the shrinkage of solidifying alloy by investment expansion. The metal casting ring restricts the thermal expansion of investment because the thermal expansion of the ring is lesser than that of the investment. The use of casting ring was challenged with the introduction of the ringless technique. MATERIALS AND METHODS A total of 40 test samples of nickel chromium (Ni-Cr) cast copings were obtained from the patterns fabricated using inlay casting wax. The 20 wax patterns were invested using metal ring and 20 wax patterns were invested using the ringless investment system. Of both the groups, 10 samples underwent conventional casting, and the other 10 underwent accelerated casting. The patterns were casted using the induction casting technique. All the test samples of cast copings were evaluated for vertical marginal gaps at four points on the die employing a stereo optical microscope. RESULTS The vertical marginal discrepancy data obtained were tabulated. Mean and standard deviations were obtained. Vertical discrepancies were analyzed using analysis of variance and Tukey honestly significantly different. The data obtained were found to be very highly significant (P < 0.001). Mean vertical gap was the maximum for Group II (53.64 μm) followed by Group IV (47.62 μm), Group I (44.83 μm) and Group III (35.35 μm). CONCLUSION The Ni-Cr cast copings fabricated with the conventional casting using ringless investment system showed significantly better marginal fit than that of cast copings fabricated from conventional and accelerated casting with metal ring investment and accelerated casting using ringless investment since those copings had shown the least vertical marginal discrepancies among the four methods evaluated in this study.
Collapse
Affiliation(s)
- Deepa Alex
- Department of Prosthodontics, A.J. Institute of Dental Sciences, Mangalore, Karnataka, India
| | - Y Bharath Shetty
- Department of Prosthodontics, A.J. Institute of Dental Sciences, Mangalore, Karnataka, India
| | - Glynis Anita Miranda
- Department of Prosthodontics, A.J. Institute of Dental Sciences, Mangalore, Karnataka, India
| | - M Bharath Prabhu
- Department of Prosthodontics, A.J. Institute of Dental Sciences, Mangalore, Karnataka, India
| | - Reshma Karkera
- Department of Prosthodontics, A.J. Institute of Dental Sciences, Mangalore, Karnataka, India
| |
Collapse
|