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Evaluation of the marginal and internal gap of metal-ceramic crown fabricated with a selective laser sintering technology: two- and three-dimensional replica techniques.

Kim KB, Kim JH, Kim WC, Kim HY, Kim JH - J Adv Prosthodont (2013)

Bottom Line: The marginal and internal gaps were measured by two-dimensional and three-dimensional replica techniques, respectively.The Wilcoxon signed-rank test, the Wilcoxon rank-sum test and nonparametric ANCOVA were used for statistical analysis (α=.05).Although the gap of the FDPs produced by the SLS was greater than that of the FDPs produced by the conventional casting in all measured areas, none exceeded the clinically acceptable range.

View Article: PubMed Central - PubMed

Affiliation: Department of Dental Laboratory Science and Engineering, Korea University, Seoul, Republic of Korea.

ABSTRACT

Purpose: One of the most important factors in evaluating the quality of fixed dental prostheses (FDPs) is their gap. The purpose of this study was to compare the marginal and internal gap of two different metal-ceramic crowns, casting and selective laser sintering (SLS), before and after porcelain firing. Furthermore, this study evaluated whether metal-ceramic crowns made using the SLS have the same clinical acceptability as crowns made by the traditional casting.

Materials and methods: The 10 study models were produced using stone. The 20 specimens were produced using the casting and the SLS methods; 10 samples were made in each group. After the core gap measurements, 10 metal-ceramic crowns in each group were finished using the conventional technique of firing porcelain. The gap of the metal-ceramic crowns was measured. The marginal and internal gaps were measured by two-dimensional and three-dimensional replica techniques, respectively. The Wilcoxon signed-rank test, the Wilcoxon rank-sum test and nonparametric ANCOVA were used for statistical analysis (α=.05).

Results: In both groups, the gap increased after completion of the metal-ceramic crown compared to the core. In all measured areas, the gap of the metal cores and metal-ceramic crowns produced by the SLS was greater than that of the metal cores and metal-ceramic crowns produced using the casting. Statistically significant differences were found between cast and SLS (metal cores and metal-ceramic crown).

Conclusion: Although the gap of the FDPs produced by the SLS was greater than that of the FDPs produced by the conventional casting in all measured areas, none exceeded the clinically acceptable range.

No MeSH data available.


Measurement of marginal gap by digital microscope at ×160 magnification (Orange color: light body silicone; purple color: medium body silicone).
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Figure 3: Measurement of marginal gap by digital microscope at ×160 magnification (Orange color: light body silicone; purple color: medium body silicone).

Mentions: To measure the marginal gap, the silicone replica was cut into eight pieces after it was completed (Fig. 2C). A total of 16 points per specimen, based on the surface of the cross-section (Fig. 2C), were measured, and the average was defined as the marginal gap for each specimen. The marginal gap measurement was made under ×160 magnification using a KH-7000 digital microscope (HIROX, Tokyo, Japan), and the vertical distance from the abutment tooth to the FDPs was measured as described previously (Fig. 3).20 A total of 20 specimens were measured 320 times.


Evaluation of the marginal and internal gap of metal-ceramic crown fabricated with a selective laser sintering technology: two- and three-dimensional replica techniques.

Kim KB, Kim JH, Kim WC, Kim HY, Kim JH - J Adv Prosthodont (2013)

Measurement of marginal gap by digital microscope at ×160 magnification (Orange color: light body silicone; purple color: medium body silicone).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3675292&req=5

Figure 3: Measurement of marginal gap by digital microscope at ×160 magnification (Orange color: light body silicone; purple color: medium body silicone).
Mentions: To measure the marginal gap, the silicone replica was cut into eight pieces after it was completed (Fig. 2C). A total of 16 points per specimen, based on the surface of the cross-section (Fig. 2C), were measured, and the average was defined as the marginal gap for each specimen. The marginal gap measurement was made under ×160 magnification using a KH-7000 digital microscope (HIROX, Tokyo, Japan), and the vertical distance from the abutment tooth to the FDPs was measured as described previously (Fig. 3).20 A total of 20 specimens were measured 320 times.

Bottom Line: The marginal and internal gaps were measured by two-dimensional and three-dimensional replica techniques, respectively.The Wilcoxon signed-rank test, the Wilcoxon rank-sum test and nonparametric ANCOVA were used for statistical analysis (α=.05).Although the gap of the FDPs produced by the SLS was greater than that of the FDPs produced by the conventional casting in all measured areas, none exceeded the clinically acceptable range.

View Article: PubMed Central - PubMed

Affiliation: Department of Dental Laboratory Science and Engineering, Korea University, Seoul, Republic of Korea.

ABSTRACT

Purpose: One of the most important factors in evaluating the quality of fixed dental prostheses (FDPs) is their gap. The purpose of this study was to compare the marginal and internal gap of two different metal-ceramic crowns, casting and selective laser sintering (SLS), before and after porcelain firing. Furthermore, this study evaluated whether metal-ceramic crowns made using the SLS have the same clinical acceptability as crowns made by the traditional casting.

Materials and methods: The 10 study models were produced using stone. The 20 specimens were produced using the casting and the SLS methods; 10 samples were made in each group. After the core gap measurements, 10 metal-ceramic crowns in each group were finished using the conventional technique of firing porcelain. The gap of the metal-ceramic crowns was measured. The marginal and internal gaps were measured by two-dimensional and three-dimensional replica techniques, respectively. The Wilcoxon signed-rank test, the Wilcoxon rank-sum test and nonparametric ANCOVA were used for statistical analysis (α=.05).

Results: In both groups, the gap increased after completion of the metal-ceramic crown compared to the core. In all measured areas, the gap of the metal cores and metal-ceramic crowns produced by the SLS was greater than that of the metal cores and metal-ceramic crowns produced using the casting. Statistically significant differences were found between cast and SLS (metal cores and metal-ceramic crown).

Conclusion: Although the gap of the FDPs produced by the SLS was greater than that of the FDPs produced by the conventional casting in all measured areas, none exceeded the clinically acceptable range.

No MeSH data available.