Effect of the Crystallization Process on the Marginal and Internal Gaps of Lithium Disilicate CAD/CAM Crowns.
The aim of this study is to quantify the effect of the crystallization process on lithium disilicate ceramic crowns fabricated using a computer-aided design/computer-aided manufacturing (CAD/CAM) system and to determine whether the effect of crystallization is clinically acceptable by comparing values of fit before and after the crystallization process. The mandibular right first molar was selected as the abutment for the experiments. Fifteen working models were prepared. Lithium disilicate crowns appropriate for each abutment were prepared using a commercial CAD/CAM system. Gaps in the marginal area and 4 internal areas of each crown were measured twice-before and after crystallization-using the silicone replica technique. The mean values of fit before and after crystallization were analyzed using a paired t-test to examine whether the conversion that occurred during crystallization affected marginal and internal gaps (α = 0.05). Gaps increased in the marginal area and decreased in the internal areas after crystallization. There were statistically significant differences in all of the investigated areas (P < 0.05). None of the values for marginal and internal fit of lithium disilicate CAD/CAM crowns after crystallization exceeded 120 μm, which is the clinically acceptable threshold.
Department of Dental Technology, School of Medical and Public Health, Kyungdong University, 815 Gyeonhwon-ro, Wonju, Gangwondo 24695, Republic of Korea.
Jae-Hong
JH
Kim
Department of Dental Biomaterials, College of Dentistry, Wonkwang University, 344-2 Shinyong-dong, Iksan, Jeonbuk 570-749, Republic of Korea.
Seunghan
S
Oh
Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Republic of Korea; DNV GL Business Assurance Korea Ltd., 18th Floor, Kyobo Building, 1 Jong-ro, Jongno-gu, Seoul 03154, Republic of Korea.
Soo-Hyuk
SH
Uhm
D017076:Computer-Aided Design; D003460:Crystallization; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design / Q000379:methods*; D008963:Molar / Q000737:chemistry*; D012828:Silicones / Q000737:chemistry; D013499:Surface Properties; D019228:Tooth Crown / Q000737:chemistry*
D012828:Silicones; C493120:lithia disilicate; D003776:Dental Porcelain