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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.


Three-dimensional replica technique. A: The 3D surface model from the digitization of the study model used as the control model (CAD reference model; CRM), B: The point cloud model is the digitization of the light body silicone, C: The point cloud model is projected onto the surface of the CRM. The distribution of the internal gaps was measured and depicted on the color different map.
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Figure 4: Three-dimensional replica technique. A: The 3D surface model from the digitization of the study model used as the control model (CAD reference model; CRM), B: The point cloud model is the digitization of the light body silicone, C: The point cloud model is projected onto the surface of the CRM. The distribution of the internal gaps was measured and depicted on the color different map.

Mentions: The internal gap of the specimens were measured using the 3D replica technique. According to this method, the study models were digitalized by scanning with an Identica dental scanner (Medit, Seoul, Korea) (Fig. 4A). After scanning, the inside of the FDPs of the study model was filled with light body silicone (Aquasil Ultra XLV; Dentsply DeTrey GmbH) in a manner similar to the conventional silicone replica technique. Subsequently, 50 N of pressure was applied along the long axis for 10 minutes. Because the extra-light body silicone flows out in the direction of the FDPs and interferes with 3D measurements, this substance was carefully removed before the silicone hardened. After the light body silicone hardened, only the FDPs were carefully removed from the model and the light body silicone replica was kept on the teeth model while a digital replica was made using a dental scanner (Identica; Medit).


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)

Three-dimensional replica technique. A: The 3D surface model from the digitization of the study model used as the control model (CAD reference model; CRM), B: The point cloud model is the digitization of the light body silicone, C: The point cloud model is projected onto the surface of the CRM. The distribution of the internal gaps was measured and depicted on the color different map.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: Three-dimensional replica technique. A: The 3D surface model from the digitization of the study model used as the control model (CAD reference model; CRM), B: The point cloud model is the digitization of the light body silicone, C: The point cloud model is projected onto the surface of the CRM. The distribution of the internal gaps was measured and depicted on the color different map.
Mentions: The internal gap of the specimens were measured using the 3D replica technique. According to this method, the study models were digitalized by scanning with an Identica dental scanner (Medit, Seoul, Korea) (Fig. 4A). After scanning, the inside of the FDPs of the study model was filled with light body silicone (Aquasil Ultra XLV; Dentsply DeTrey GmbH) in a manner similar to the conventional silicone replica technique. Subsequently, 50 N of pressure was applied along the long axis for 10 minutes. Because the extra-light body silicone flows out in the direction of the FDPs and interferes with 3D measurements, this substance was carefully removed before the silicone hardened. After the light body silicone hardened, only the FDPs were carefully removed from the model and the light body silicone replica was kept on the teeth model while a digital replica was made using a dental scanner (Identica; Medit).

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.