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Accuracy evaluation of metal copings fabricated by computer-aided milling and direct metal laser sintering systems.

Park JK, Lee WS, Kim HY, Kim WC, Kim JH - J Adv Prosthodont (2015)

Bottom Line: The mean gap differed significantly with fabrication methods (P<.001).Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (<120 µm).However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.

View Article: PubMed Central - PubMed

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

ABSTRACT

Purpose: To assess the marginal and internal gaps of the copings fabricated by computer-aided milling and direct metal laser sintering (DMLS) systems in comparison to casting method.

Materials and methods: Ten metal copings were fabricated by casting, computer-aided milling, and DMLS. Seven mesiodistal and labiolingual positions were then measured, and each of these were divided into the categories; marginal gap (MG), cervical gap (CG), axial wall at internal gap (AG), and incisal edge at internal gap (IG). Evaluation was performed by a silicone replica technique. A digital microscope was used for measurement of silicone layer. Statistical analyses included one-way and repeated measure ANOVA to test the difference between the fabrication methods and categories of measured points (α=.05), respectively.

Results: The mean gap differed significantly with fabrication methods (P<.001). Casting produced the narrowest gap in each of the four measured positions, whereas CG, AG, and IG proved narrower in computer-aided milling than in DMLS. Thus, with the exception of MG, all positions exhibited a significant difference between computer-aided milling and DMLS (P<.05).

Conclusion: Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (<120 µm). However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.

No MeSH data available.


Measurement of the marginal area silicone thickness by digital microscopy (magnification 160×).
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Figure 3: Measurement of the marginal area silicone thickness by digital microscopy (magnification 160×).

Mentions: To measure the marginal and internal gaps, a silicone replica technique was used. For this, the fabricated metalceramic crown copings were first filled with yellow lightbody silicone (Aquasil Ultra XLV; Dentsply Caulk, Milford, DE, USA), and then placed on a stone die and fitted by applying an even finger pressure of 50 N on an electronic scale. Next, the metal copings were carefully separated, with the hardened yellow light-body silicone film produced used to represent the gaps between the copings and the die. To keep bubbles from rising around the margin of the replicated silicone, and to measure the gap with ease, a contrasting blue light-body silicone (Aquasil Ultra LV; Dentsply Caulk, Milford, DE, USA) was then added. As the light-body silicone film adhering to the stone die was often too thin to resist tearing or to maintain its shape, it was additionally covered with a strong heavy-body silicone for stabilization (Aquasil Ultra Monophase; Dentsply Caulk, Milford, DE, USA). Finally, the replicated silicone was cut using a razor blade along the mesiodistal and labiolingual directions, with the thickness of each section examined under a digital microscope at 160× magnification (KH-7700; Hirox, Tokyo, Japan). Digital images were taken with the digital microscope. The images were measured by the internal stored imaging data software (KH-7700 software Ver. 2.10c; Hirox, Tokyo, Japan) which was equipped to the digital microscope machine (Fig. 3).


Accuracy evaluation of metal copings fabricated by computer-aided milling and direct metal laser sintering systems.

Park JK, Lee WS, Kim HY, Kim WC, Kim JH - J Adv Prosthodont (2015)

Measurement of the marginal area silicone thickness by digital microscopy (magnification 160×).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414942&req=5

Figure 3: Measurement of the marginal area silicone thickness by digital microscopy (magnification 160×).
Mentions: To measure the marginal and internal gaps, a silicone replica technique was used. For this, the fabricated metalceramic crown copings were first filled with yellow lightbody silicone (Aquasil Ultra XLV; Dentsply Caulk, Milford, DE, USA), and then placed on a stone die and fitted by applying an even finger pressure of 50 N on an electronic scale. Next, the metal copings were carefully separated, with the hardened yellow light-body silicone film produced used to represent the gaps between the copings and the die. To keep bubbles from rising around the margin of the replicated silicone, and to measure the gap with ease, a contrasting blue light-body silicone (Aquasil Ultra LV; Dentsply Caulk, Milford, DE, USA) was then added. As the light-body silicone film adhering to the stone die was often too thin to resist tearing or to maintain its shape, it was additionally covered with a strong heavy-body silicone for stabilization (Aquasil Ultra Monophase; Dentsply Caulk, Milford, DE, USA). Finally, the replicated silicone was cut using a razor blade along the mesiodistal and labiolingual directions, with the thickness of each section examined under a digital microscope at 160× magnification (KH-7700; Hirox, Tokyo, Japan). Digital images were taken with the digital microscope. The images were measured by the internal stored imaging data software (KH-7700 software Ver. 2.10c; Hirox, Tokyo, Japan) which was equipped to the digital microscope machine (Fig. 3).

Bottom Line: The mean gap differed significantly with fabrication methods (P<.001).Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (<120 µm).However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.

View Article: PubMed Central - PubMed

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

ABSTRACT

Purpose: To assess the marginal and internal gaps of the copings fabricated by computer-aided milling and direct metal laser sintering (DMLS) systems in comparison to casting method.

Materials and methods: Ten metal copings were fabricated by casting, computer-aided milling, and DMLS. Seven mesiodistal and labiolingual positions were then measured, and each of these were divided into the categories; marginal gap (MG), cervical gap (CG), axial wall at internal gap (AG), and incisal edge at internal gap (IG). Evaluation was performed by a silicone replica technique. A digital microscope was used for measurement of silicone layer. Statistical analyses included one-way and repeated measure ANOVA to test the difference between the fabrication methods and categories of measured points (α=.05), respectively.

Results: The mean gap differed significantly with fabrication methods (P<.001). Casting produced the narrowest gap in each of the four measured positions, whereas CG, AG, and IG proved narrower in computer-aided milling than in DMLS. Thus, with the exception of MG, all positions exhibited a significant difference between computer-aided milling and DMLS (P<.05).

Conclusion: Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (<120 µm). However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.

No MeSH data available.