Marginal fit of castable ceramic crowns

Holmes, J. R.; Sulik, William D.; Holland, Gene A.; Bayne, Stephen C.

doi:10.1016/0022-3913(92)90153-2

Cited by 100 publications

(77 citation statements)

References 8 publications

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“…Groten and others 18 suggested a measurement of ideally 50 points, or at least 20 to 25 measurements per crown. In earlier studies, the reliability of the marginal opening measurements were either validated by the larger sample sizes ranging from 5-10 specimens 1,[18][19] or an increased number of measurements from different points. In the current study, seven specimens for each finish line type yielded up to 64 MO and 16 AMO measurement points.…”

Section: Discussionmentioning

confidence: 99%

“…Luting agent solubility may, in time, result in gap formation between the tooth and the restorative material, leading to microleakage, plaque accumulation, caries and subsequent failure of the restoration. While a clinically acceptable range of marginal discrepancies is advised to be less than 120 µm, 1 in CAD/CAM or copy-milling systems, the marginal opening has been reported to range between 60 µm and 300 µm. [2][3] Several in vitro studies demonstrated that the marginal adaptation of metal-ceramic FPDs is influenced by the type of cervical finish line, shrinkage after firing procedures of the veneering ceramic, 4-5 differences in thermal expansion coefficients of the framework and veneering ceramic and, most importantly, the amount of circumferential ceramic thickness of the substructure.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Cervical Finish Line Type on the Marginal Adaptation of Zirconia Ceramic Crowns

Çömlekoğlu¹,

Dündar²,

Özcan³

et al. 2009

Operative Dentistry

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Cervical finish line type has an influence on the marginal adaptation of Y-TZP restorations. Both shoulder and mini-chamfer exhibited the least marginal opening values for zirconia crowns and can be recommended for clinical applications. SUMMARYThe current study evaluated the effect of different cervical finish line designs on the marginal adaptation of a zirconia ceramic. Four different marginal finish lines (c: chamfer, mc: mini-chamfer, fe: feather-edge and s: rounded shoulder) were prepared on phantom incisors. Die models for each preparation group (N=28, n=7 per finish line design group) were made of epoxy resin. Y-TZP (ICE Zirkon) frameworks were manufactured by a copy-milling system (Zirconzahn) using prefabricated blanks and tried on the master models for initial adaptation of the framework; they were then sintered, followed by veneering (Zirconzahn). The finished crowns were cemented with a polycarboxylate cement (Poly F) under 300 g load and ultrasonically cleaned. The specimens were sliced and the marginal gap was measured, considering absolute marginal opening (AMO) and marginal opening (MO) for each coping under a stereomicroscope with image processing software (Lucia). The measurements were statistically analyzed using the Kruskal Wallis, Mann Whitney and Wilcoxon Signed Ranks tests at a significance level of α α=0.01. Means of AMO measurement (µm) for the feather-edge finish line (87 ± 10) was significantly lower than that of the chamfer (144 ± 14), shoulder (114 ± 16) and mini-chamfer finish line types (114 ± 11) (p<0.01). Means of MO measurements was the lowest for feather-edge finish line (68 ± 9) (p<0.01) and then, in ascending order, shoulder (95 ± 9), mini-chamfer (97 ± 12) and chamfer (128 ± 10). The cervical finish line type

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Cervical Finish Line Type on the Marginal Adaptation of Zirconia Ceramic Crowns

Çömlekoğlu¹,

Dündar²,

Özcan³

et al. 2009

Operative Dentistry

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“…However, the maximum marginal gap has been suggested as the most clinically relevant measure [5], since this would likely form the point of failure of the marginal seal. The acceptable size of a marginal gap is also not clear, although values in the region of 100µm have been suggested for conventional cements [6].…”

Section: Introductionmentioning

confidence: 99%

Confounding factors affecting the marginal quality of an intra-oral scan

Keeling

Ferrari

2017

Journal of Dentistry

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Title: Confounding Factors Affecting the Marginal Quality of an Intra-Oral ScanObjectives: To assess the effect of clinical factors on the quality of intra-oral scans of crown margins. These factors are; presence of adjacent teeth, proximity to gingivae, encumbrance of wand positioning within oral cavity. Methods:A typodont lower molar (Frasaco, Germany) was prepared for an all-ceramic crown with 1.5mm supraginigival (lingual) and equigingival (buccal) margins. The tooth was scanned in a model scanner, creating a master scan.An intra-oral scanner (IOS) (Omnicam, Sirona Dental) was used to acquire sets of 5 scans each, under varying conditions; 1)the presence/absence of adjacent teeth, 2)model mounted in manikin head/hand-held, 3)with/without a 1mm shim to elevate the margin. Every combination was investigated, yielding 40 scans (8 groups of 5).The master scan margin was identified by selecting the highest curvature region (>1.8). The master was aligned to each IOS scan, and 4 regions of each IOS scan margin were extracted, lying within 100µm of predefined mesial, distal, buccal and lingual sections of the master margin.The mean curvature of each margin section was calculated using Meshlab. The effect of each confounding factor on margin curvature was analysed using ANOVA.Results: Lingual margin curvature remained consistent regardless of scanning conditions. Buccal margin curvature was significantly affected when located equigingivally. Mesial margin curvature was significantly affected in the presence of adjacent teeth and proximity to the gingivae. Distal margin curvature was significantly affected by all three confounding factors. Conclusions:The curvature (sharpness) of the margin recorded by a commercial IOS is significantly affected by clinical factors obscuring visibility.

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“…According to Holmes et al [16] a marginal gap 100 to 120 µm is acceptable to avoid potential degradation or dissolution problems that could contribute to cement loss. However, other studies [17][18][19] have considered the marginal gap values of 100 to 200 µm to be clinically acceptable for cemented restorations.…”

Section: Discussionmentioning

confidence: 99%

Effect of different impression methods and ceramic materials on adaptation of inlays

Rippe

Guerra

Coelho

et al. 2018

BDS

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Objective: The aim of this study was to evaluate the internal and marginal adaptation of inlays fabricated from different types of impressions (conventional and digital) and different ceramics (feldspathic and lithium disilicate). Material and Methods: Forty premolars were prepared for all-ceramic inlay restoration and assigned to 4 groups (n=10), according to the impression method (conventional with addition silicone and digital impressions) and ceramic type (lithium disilicate and feldspathic ceramic blocks). For each type of impression, 10 inlays were fabricated from lithium disilicate blocks and the other 10 from feldspathic ceramic blocks, by means of the CAD-CAM system. The internal adaptation was analyzed by replica. The marginal fit was analyzed under a stereomicroscope by directly measuring the gap formed between the inlay and the tooth in the proximal and occlusal regions. Results: The marginal or internal adaptations were not affected by type of impression (conventional = digital impression), irrespective of the ceramic type. Only the internal adaptation was affected by material, i.e., feldspathic ceramic had lower values than disilicate ceramic, when considering the digital impression. Conclusion: The conventional and digital impressions promote similar marginal and internal adaptation of tested feldspathic and disilicate ceramic inlays. For digital impression the feldspathic ceramic showed better internal adaptation than lithium disilicate. KeywordsCeramics; Dental internal adaptation; Dental marginal adaptation; Dental impression technique.

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Marginal fit of castable ceramic crowns

Cited by 100 publications

References 8 publications

Influence of Cervical Finish Line Type on the Marginal Adaptation of Zirconia Ceramic Crowns

Influence of Cervical Finish Line Type on the Marginal Adaptation of Zirconia Ceramic Crowns

Confounding factors affecting the marginal quality of an intra-oral scan

Effect of different impression methods and ceramic materials on adaptation of inlays

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