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A Comparison of the Marginal and Internal Fit of Cobalt- Chromium Copings Fabricated by Two Different CAD/CAM Systems (CAD/ Milling, CAD/ Ceramill Sintron) | ||
| Journal of Dentistry | ||
| مقاله 2، دوره 17، شماره 4، اسفند 2016، صفحه 301-308 اصل مقاله (396.79 K) | ||
| نوع مقاله: Original Article | ||
| نویسندگان | ||
| Mahroo Vojdani1؛ Kianoosh Torabi1؛ Berivan Atashkar* 2؛ Hossein Heidari2؛ Mahshid Torabi Ardakani3 | ||
| 1Dept. of Prosthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran. | ||
| 2Postgraduate Student in Prosthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran. | ||
| 3Dept. of Prosthodontics, School of Dentistry, Azad University of Medical Sciences, Tehran, Iran. | ||
| چکیده | ||
| Statement of the Problem: Marginal fitness is the most important criteria for evaluation of the clinical acceptability of a cast restoration. Marginal gap which is due to cement solubility and plaque retention is potentially detrimental to both tooth and periodontal tissues.Purpose: This in vitro study aimed to evaluate the marginal and internal fit of cobalt- chromium (Co-Cr) copings fabricated by two different CAD/CAM systems: (CAD/ milling and CAD/ Ceramill Sintron).Materials and Method: We prepared one machined standard stainless steel master model with following dimensions: 7 mm height, 5mm diameter, 90˚ shoulder marginal finish line with 1 mm width, 10˚ convergence angle and anti-rotational surface on the buccal aspect of the die. There were 10 copings produced from hard presintered Co-Cr blocks according to CAD/ Milling technique and ten copings from soft non- presintered Co-Cr blocks according to CAD/ Ceramill Sintron technique. Marginal and internal accuracies of copings were documented by the replica technique. Replicas were examined at ten reference points under a digital microscope (230X). The Student's t-test was used for statistical analysis. p< 0.001 was considered significant.Results: Statistically significant differences existed between the groups (p< 0.001). The CAD/milling group (hard copings) had a mean marginal discrepancy (MD) of 104 µm, axial discrepancy (AD) of 23 µm and occlusal discrepancy of 130 µm. For CAD/ Ceramill Sintron group, these values were 195 µm (MD), 46 µm (AD), and 232 µm (OD). Internal total discrepancy (ITD) for the CAD/milling group was 77 µm, whereas for the CAD/Ceramill Sintron group was 143 µm.Conclusion: Hard presintered Co-Cr copings had significantly higher marginal and internal accuracies compared to the soft non-presintered copings.Keywords ● Marginal and Internal fit ● CAD/CAM ● Ceramill Sintron ● Base Metal Alloy | ||
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