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Effects of the sintering conditions of dental zirconia ceramics on the grain size and translucency.

Kim MJ, Ahn JS, Kim JH, Kim HY, Kim WC - J Adv Prosthodont (2013)

Bottom Line: The mean grain size ranged from 347-1,512 nm for Lava and 373-1,481 nm for KaVo.The mean light transmittance values of Lava and KaVo were 28.39-34.48% and 28.09-30.50%, respectively.To obtain more translucent dental zirconia restorations, shorter sintering times should be considered.

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: This study aimed to identify the effects of the sintering conditions of dental zirconia on the grain size and translucency.

Materials and methods: Ten specimens of each of two commercial brands of zirconia (Lava and KaVo) were made and sintered under five different conditions. Microwave sintering (MS) and conventional sintering (CS) methods were used to fabricate zirconia specimens. The dwelling time was 20 minutes for MS and 20 minutes, 2, 10, and 40 hours for CS. The density and the grain size of the sintered zirconia blocks were measured. Total transmission measurements were taken using a spectrophotometer. Two-way analysis of variance model was used for the analysis and performed at a type-one error rate of 0.05.

Results: There was no significant difference in density between brands and sintering conditions. The mean grain size increased according to sintering conditions as follows: MS-20 min, CS-20 min, CS-2 hr, CS-10 hr, and CS-40 hr for both brands. The mean grain size ranged from 347-1,512 nm for Lava and 373-1,481 nm for KaVo. The mean light transmittance values of Lava and KaVo were 28.39-34.48% and 28.09-30.50%, respectively.

Conclusion: Different sintering conditions resulted in differences in grain size and light transmittance. To obtain more translucent dental zirconia restorations, shorter sintering times should be considered.

No MeSH data available.


Related in: MedlinePlus

SEM images (Original magnification ×10,000) of the polished and thermally etched surface of Lava specimens sintered for various times using different approaches: A: MS-20 minutes, B: CS-20 minutes, C: CS-2 hours, D: CS-10 hours, and E: CS-40 hours. The black arrows indicate grain boundary cracks.
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Figure 1: SEM images (Original magnification ×10,000) of the polished and thermally etched surface of Lava specimens sintered for various times using different approaches: A: MS-20 minutes, B: CS-20 minutes, C: CS-2 hours, D: CS-10 hours, and E: CS-40 hours. The black arrows indicate grain boundary cracks.

Mentions: The mean grain size ranged from 347-1,512 nm for Lava and 373-1, 481 nm for KaVo according to the sintering conditions. Both Lava and KaVo had the smallest mean grain sizes of 347 and 373 nm, respectively, at MS-20 minutes, and the largest mean grain sizes of 1,512 and 1,481 nm, respectively, at CS-40 hours (Table 3). The longer the sintering time, the larger the resulting grain. This finding was confirmed by SEM images (Fig. 1).


Effects of the sintering conditions of dental zirconia ceramics on the grain size and translucency.

Kim MJ, Ahn JS, Kim JH, Kim HY, Kim WC - J Adv Prosthodont (2013)

SEM images (Original magnification ×10,000) of the polished and thermally etched surface of Lava specimens sintered for various times using different approaches: A: MS-20 minutes, B: CS-20 minutes, C: CS-2 hours, D: CS-10 hours, and E: CS-40 hours. The black arrows indicate grain boundary cracks.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3675289&req=5

Figure 1: SEM images (Original magnification ×10,000) of the polished and thermally etched surface of Lava specimens sintered for various times using different approaches: A: MS-20 minutes, B: CS-20 minutes, C: CS-2 hours, D: CS-10 hours, and E: CS-40 hours. The black arrows indicate grain boundary cracks.
Mentions: The mean grain size ranged from 347-1,512 nm for Lava and 373-1, 481 nm for KaVo according to the sintering conditions. Both Lava and KaVo had the smallest mean grain sizes of 347 and 373 nm, respectively, at MS-20 minutes, and the largest mean grain sizes of 1,512 and 1,481 nm, respectively, at CS-40 hours (Table 3). The longer the sintering time, the larger the resulting grain. This finding was confirmed by SEM images (Fig. 1).

Bottom Line: The mean grain size ranged from 347-1,512 nm for Lava and 373-1,481 nm for KaVo.The mean light transmittance values of Lava and KaVo were 28.39-34.48% and 28.09-30.50%, respectively.To obtain more translucent dental zirconia restorations, shorter sintering times should be considered.

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: This study aimed to identify the effects of the sintering conditions of dental zirconia on the grain size and translucency.

Materials and methods: Ten specimens of each of two commercial brands of zirconia (Lava and KaVo) were made and sintered under five different conditions. Microwave sintering (MS) and conventional sintering (CS) methods were used to fabricate zirconia specimens. The dwelling time was 20 minutes for MS and 20 minutes, 2, 10, and 40 hours for CS. The density and the grain size of the sintered zirconia blocks were measured. Total transmission measurements were taken using a spectrophotometer. Two-way analysis of variance model was used for the analysis and performed at a type-one error rate of 0.05.

Results: There was no significant difference in density between brands and sintering conditions. The mean grain size increased according to sintering conditions as follows: MS-20 min, CS-20 min, CS-2 hr, CS-10 hr, and CS-40 hr for both brands. The mean grain size ranged from 347-1,512 nm for Lava and 373-1,481 nm for KaVo. The mean light transmittance values of Lava and KaVo were 28.39-34.48% and 28.09-30.50%, respectively.

Conclusion: Different sintering conditions resulted in differences in grain size and light transmittance. To obtain more translucent dental zirconia restorations, shorter sintering times should be considered.

No MeSH data available.


Related in: MedlinePlus