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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.


Two-dimensional replica technique. A: The inside of the core was first filled with the light body silicone and pressure (50 N for 10 min), B: Stabilization of the light body silicone using medium body silicone, C: The silicone replica sectioned four times (red line) and sixteen marginal points (P1-P16) were measured on each specimen.
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Figure 2: Two-dimensional replica technique. A: The inside of the core was first filled with the light body silicone and pressure (50 N for 10 min), B: Stabilization of the light body silicone using medium body silicone, C: The silicone replica sectioned four times (red line) and sixteen marginal points (P1-P16) were measured on each specimen.

Mentions: The silicone replica technique was used to measure the marginal gap after the SLS core group and casting core group specimens were produced. Using this technique, the inside of the core was first filled with light body silicone (Aquasil Ultra XLV; Dentsply DeTrey GmbH, Konstanz, Germany) and pressure was applied along the major axis of the teeth at 50 N for 10 minutes (Fig. 2A), until the light body silicone hardened. After hardening, the core was carefully removed from the study model, and the light body silicone was strengthened using medium body silicone (Aquasil Ultra Monophase; Dentsply DeTrey GmbH) (Fig. 2B). This procedure is necessary because it is difficult to cut light body silicon accurately, since it does not maintain its shape. Therefore, reinforcing with medium body silicone enables accurate cutting from a specified direction.


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)

Two-dimensional replica technique. A: The inside of the core was first filled with the light body silicone and pressure (50 N for 10 min), B: Stabilization of the light body silicone using medium body silicone, C: The silicone replica sectioned four times (red line) and sixteen marginal points (P1-P16) were measured on each specimen.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Two-dimensional replica technique. A: The inside of the core was first filled with the light body silicone and pressure (50 N for 10 min), B: Stabilization of the light body silicone using medium body silicone, C: The silicone replica sectioned four times (red line) and sixteen marginal points (P1-P16) were measured on each specimen.
Mentions: The silicone replica technique was used to measure the marginal gap after the SLS core group and casting core group specimens were produced. Using this technique, the inside of the core was first filled with light body silicone (Aquasil Ultra XLV; Dentsply DeTrey GmbH, Konstanz, Germany) and pressure was applied along the major axis of the teeth at 50 N for 10 minutes (Fig. 2A), until the light body silicone hardened. After hardening, the core was carefully removed from the study model, and the light body silicone was strengthened using medium body silicone (Aquasil Ultra Monophase; Dentsply DeTrey GmbH) (Fig. 2B). This procedure is necessary because it is difficult to cut light body silicon accurately, since it does not maintain its shape. Therefore, reinforcing with medium body silicone enables accurate cutting from a specified direction.

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.