title: Evaluation of internal and marginal fit of two metal ceramic system - in vitro study.
abstract: BACKGROUND
  The high strength porcelain fused metal crowns have been extensively used in dentistry. However, the fit is the most encountered problems in porcelain fused metal crowns. This mainly depends on the fabrication technique.
  
  
  OBJECTIVE
  The purpose was to compare the internal and marginal fit of laser sintered and conventionally casted Cobalt-Chromium copings.
  
  
  METHODS
  Twenty stainless steel dies of dimension 15 x 10 mm with 1 mm finish margin were fabricated using CAD-CAM technology. Twenty dies were divided into two groups Group 1 and Group 2 containing 10 samples each. All 20 dies were scanned using LAVA 3M scanner and data were used to fabricate metal copings using Laser sintering technique (Group-1) and Conventional casting technique (Group-2). Copings were cemented onto respective dies and finished and standardized sectioning were made. The sectioned models were scanned under stereomicroscope at 50 x magnification for internal and marginal fit evaluation.
  
  
  RESULTS
  Mean and standard deviation of internal and marginal discrepancy of laser sintered copings/conventional cast metal copings was 107.6 ± 10.9μ and 102.1 ± 17.2μ/187.09 ± 11.47 μ and 176.57 ± 25.82 μ respectively. Statistical analysis showed the laser sintered copings have lesser internal and marginal discrepancy than conventional casted copings with p value < 0.001.
  
  
  CONCLUSIONS
  The laser sintered Co-Cr copings showed better internal and marginal fit when compared to that of conventional Co-Cr casted copings.
authors: Assistant Professor, Department of Prosthodontics, Srimuthukumaran Medical College , Chennai, India .
authors: Harish
authors: H
authors: V
authors: Assistant Professor, Department of Prosthodontics, Indira Gandhi institute of Dental Sciences , Pondicherry, India .
authors: Mohamed
authors: M
authors: Ali S A
authors: Assistant Professor, Department of Prosthodontics, Menakshi ammal Dental College , Chennai, India .
authors: Jagadesan
authors: J
authors: N
authors: Consultant Endodontist & Private practioner, Pondicherry, India .
authors: Mohamed
authors: M
authors: Ifthikar
authors: Assistant Professor, Department of Prosthodontics, Indira Gandhi institute of Dental Sciences , Pondicherry, India .
authors: Siva
authors: S
authors: Senthil
authors: Consultant Prosthodontist & Private Practioner, West Bengal, India .
authors: Debasish
authors: D
authors: Basak
authors: Consultant Prosthodontist, Vasan Dental Care , Trichy, India .
authors: Febel
authors: F
authors: Huda
authors: Consultant Prosthodontist, Vasan Dental Care , Madurai, India .
authors: Priyanka
keywords: Cobalt chromium alloy; Laser sintered; Metal crowns; Porcelain fused metal crowns
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