Factors affecting the fit of porcelain jacket crowns

Hn, Alkumru; Hullah, W; Marquis, P. M.; Wilson, H.J.

doi:10.1038/sj.bdj.4806339

Cited by 25 publications

(28 citation statements)

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“…This finding was not consistent with the results of previous studies that reported on the influence of ceramic firing on marginal adaptation 6,10) . This disagreement might again reflect the differences arising from the different types of ceramic materials used in each study.…”

Section: Discussioncontrasting

confidence: 99%

“…Numerous studies have evaluated the marginal and internal adaptation of single-tooth crown restorations fabricated from various systems and materials [1][2][3][4][5] . Factors such as type of finish line design, ceramic firing effect, and materials used reportedly influence the marginal adaptation of all-ceramic crown restorations [6][7][8][9][10] . Studies that examined the influence of finish line design on adaptation yielded contradictory results.…”

Section: Introductionmentioning

confidence: 99%

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Marginal and Internal Adaptation of Zirconium Dioxide Ceramic Copings and Crowns with Different Finish Line Designs

et al. 2007

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The present study evaluated the marginal and internal adaptation of single-tooth zirconium dioxide (ZrO2) ceramic copings or crowns with three different finish line designs. Twenty-four steel dies were prepared for maxillary central incisor crowns with the following finish line designs: shoulder (S), rounded shoulder (RS), and chamfer (C) preparations. Twenty-four standardized ZrO2 ceramic copings were manufactured with a CAD/CAM system (Cercon Smart Ceramics), and the crowns were finalized by veneering with a feldspathic ceramic. Measurements for marginal and internal adaptation were performed at two stages: the copings and the completed crowns. No significant differences were observed between the three groups in terms of marginal discrepancy median value: S, 73/69; RS, 61/60; C, 64/55 (μm). However, significant differences in internal adaptation were widely found among all groups: S, 117/111; RS, 72/75; C, 56/57 (μm). As for intra-group comparisons of marginal and internal adaptation values for all groups, the differences were not significant. It was found that the finish line design seemingly wielded no influence on marginal adaptation of single-tooth ZrO2 ceramic copings and crowns. It was also observed that the marginal and internal adaptation values in the present study were all within the clinically acceptable range.

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Section: Discussioncontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Marginal and Internal Adaptation of Zirconium Dioxide Ceramic Copings and Crowns with Different Finish Line Designs

et al. 2007

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“…This phenomenon was first described in 1988 with porcelain jacket crowns. 7 While this increase in the marginal gap is detectable, the mean marginal gap of the lithium disilicate crowns in this study, even after crystallization firing, falls below the clinically acceptable limit for marginal discrepancies of 120 μm. 8 It is also consistent with the marginal gap measurements reported by others (previously mentioned).…”

Section: Discussionmentioning

confidence: 96%

Effect of Crystallization Firing on Marginal Gap of CAD/CAM Fabricated Lithium Disilicate Crowns

Gold

Ferracane

Costa

2017

Journal of Prosthodontics

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The article is associated with the American College of Prosthodontists' journal-based continuing education program. It is accompanied by an online continuing education activity worth 1 credit. Please visit www.wileyhealthlearning.com/jopr to complete the activity and earn credit. KeywordsCeramic; fit; restoration. Correspondence AbstractPurpose: To evaluate the marginal gaps of CAD/CAM (CEREC 3) produced crowns made from leucite-reinforced glass-ceramic (IPS Empress CAD) blocks (LG), and lithium-disilicate (IPS e.max CAD) blocks before (LD-B), and after (LD-A) crystallization firing. Materials and Methods: A human molar tooth (#19) was mounted with adjacent teeth on a typodont and prepared for a full-coverage ceramic crown. The typodont was assembled in the mannequin head to simulate clinical conditions. After tooth preparation 15 individual optical impressions were taken by the same operator using titanium dioxide powder and a CEREC 3 camera per manufacturer's instructions. One operator designed and machined the crowns in leucite-reinforced glass-ceramic blocks (n = 5) and lithium-disilicate blocks (n = 10) using the CEREC 3 system. The crowns were rigidly seated on the prepared tooth, and marginal gaps (μm) were measured with an optical microscope (500×) at 12 points, 3 on each of the M, B, D, and L surfaces of the leucite-reinforced glass-ceramic crowns and the lithium-disilicate crowns before and after crystallization firing. Results were analyzed by two-way ANOVA followed by a Tukey's post hoc multiple comparison test (α = 0.05). Results:The overall mean marginal gaps (μm) for the crowns evaluated were: LG = 49.2 ± 5.5, LD-B = 42.9 ± 12.2, and LD-A = 57.2 ± 16.0. The marginal gaps for LG and LD-B were not significantly different, but both were significantly less than for LD-A. Conclusions: The type of ceramic material did not affect the marginal gap of CAD/CAM crowns. The crystallization firing process required for lithium-disilicate crowns resulted in a significant increase in marginal gap size, likely due to shrinkage of the ceramic during the crystallization process. Clinical Relevance: The marginal gap of CAD/CAM-fabricated lithium disilicate crowns increases following crystallization firing. The marginal gap still remains within clinically acceptable parameters.Interest in and use of chairside computer-assisted design/ computer-assisted manufacturing (CAD/CAM) systems for the fabrication of indirect dental restorations have dramatically increased over the last decade. Marginal gaps of CAD/CAM fabricated all-ceramic restorations have improved, and with current technology, crowns can consistently be fabricated with marginal gaps in the clinically acceptable range. For example, Nakamura et al reported a marginal gap of 53 to 67 μm for CEREC 3 generated crowns.1 Anadioti et al found a 2D mean marginal gap of 74 ± 26 μm for IPS e.max CAD restorations fabricated from digital impressions.2 Ng et al measured CAD/CAM-fabricated lithium disilicate crown marginal gaps at 48 ± 25 μm.3 Keshvad et al investigated t...

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“…Ceramic crowns can be distorted during this process, which can negatively affect the fit and compromise the success of the restoration. [7][8][9][10] Important considerations are how accurate the milling process is and whether it damages the restoration.…”

Section: Discussionmentioning

confidence: 99%