jkap The Journal of Korean Academy of Prosthodontics J Korean Acad Prosthodont 0301-2875 2005-3789 The Korean Academy of Prosthodontics 10.4047/jkap.2008.46.5.528 jkap-46-528 ORIGINAL ARTICLE Comparison of marginal fit before and after porcelain build-up of two kinds of CAD/CAM zirconia all-ceramic restorations ShinHo-SikDDS, MSD1 KimSeok-GyuDDS2 Graduate student, Department of Prosthodontics, Graduate School of Clinical Dental Science, The Catholic University of Korea Professor, Department of Prosthodontics, Graduate School of Clinical Dental Science, The Catholic University of Korea Corresponding Author: Seok-Gyu Kim Department of Prosthodontics, Graduate School of Clinical Dental Science, The Catholic University of Korea, #505 Banpo-Dong, Seocho-Gu, Seoul, 137-701, Korea Tel.: +82-2-590-1620 E-mail: seokgyuk@paran.com 12 2008 ∗ 12 2008 46 5 528 534 11072008 16092008 10102008 Copyright © 2008 The Korean Academy of Prosthodontics 2008 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Purpose

Marginal fit is one of the important components for the successful prosthodontic restoration. Poor fitting margin of the restoration causes hypersensitivity, secondary caries, and plaque accumulation, which later result in prosthodontic failure. CAD/CAM zirconia all-ceramic restorations, such as LAVA® (3M ESPE, St. Paul, MN) and EVEREST® (KaVo Dental GmbH, Biberach, Germany) systems were recently introduced in Korea. It is clinically meaningful to evaluate the changes of the marginal fit of the CAD/CAM zirconia systems before and after build-up. The purposes of this study are to compare the marginal fit of the two CAD/CAM all-ceramic systems with that of the ceramometal restoration, before and after porcelain build-up

 Material and methods

A maxillary first premolar dentiform tooth was prepared with 2.0 mm occlusal reduction, 1.0 mm axial reduction, chamfer margin, and 6 degree taperness in the axial wall. The prepared dentiform die was duplicated into the metal abutment die. The metal die was placed in the dental study model, and the full arch impressions of the model were made. Twenty four copings of 3 groups which were LAVA®, EVEREST®, and ceramometal restorations were fabricated. Each coping was cemented on the metal die with color-mixed Fit-checker II® (GC Cor., Tokyo, Japan). The marginal opening of each coping was measured with Microhiscope® system (HIROX KH-1000 ING-Plus, Seoul, Korea. X300 magnification). After porcelain build-up, the marginal openings of LAVA®, EVEREST®,and ceramometal restorations were also evaluated in the same method. Statistical analysis was done with paired t-test and one-way ANOVA test.

 Results

In coping states, the mean marginal opening for EVEREST® restorations was 52.00 ± 11.94 ㎛, for LAVA® restorations 56.97 ± 10.00 ㎛, and for ceramometal restorations 97.38 ± 18.54 ㎛. After porcelain build-up, the mean marginal opening for EVEREST® restorations was 61.69 ± 19.33 ㎛, for LAVA® restorations 70.81 ± 12.99 ㎛, and for ceramometal restorations 115.25 ± 23.86 ㎛.

 Conclusion

1. LAVA® and EVEREST® restorations in comparison with ceramometal restorations showed better marginal fit, which had significant differences (P < 0.05) in coping state and also after porcelain build-up . 2. The mean marginal opening values between LAVA® and EVEREST® restorations did not showed significant differences after porcelain build-up as well as in coping state (P > .05). 3. EVEREST®, LAVA® and ceramometal restorations showed a little increased marginal opening after porcelain build-up, but did not show any statistical significance (P > .05). (J Kor Acad Prosthodont 2008;46:528-34).

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Dental study model®.

Microhiscope®(HIROX KH-1000, ING-Plus).

LAVA® coping margin.

EVEREST® coping margin.

PFM metal coping margin.

LAVA® crown margin.

EVEREST® crown margin.

PFM crown margin.

Mean marginal opening values in the coping and crown states of three groups A,B: statistical grouping of the mean marginal openings among three groups (One-way ANOVA test & Tukey grouping, P < .05).

Means and standard deviations of marginal openings in the coping and crown states of three groups (unit: ㎛)

System Number Mean (Coping) Mean (Crown) P-value
LAVA 8 56.97 ± 10.00 70.81 ± 12.99 0.1132
EVEREST 8 52.00 ± 11.94 61.69 ± 19.33 0.1091
PFM 8 97.38 ± 18.54 115.25 ± 23.86 0.0593