Marginal and Internal Fit of CAD/CAM Crowns Fabricated Over Reverse Tapered Preparations

Mejía, Jeison B. Carbajal; Yatani, Hirofumi; Wakabayashi, Keiji; Nakamura, Takashi

doi:10.1111/jopr.12715

Cited by 15 publications

(12 citation statements)

References 39 publications

(132 reference statements)

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“…Mejia et al . (2017) investigated the effect of TOC on marginal and internal fit of CAD/CAM crowns and found that the marginal gap significantly decreased as TOC increased, which supports our finding where the 20–30° taper range produced smaller MMGs than the <20° taper range . However, no TOC above 22° was assessed in their study, and therefore cannot be compared to our finding where MMG increased in the >30° taper range.…”

Section: Discussionsupporting

confidence: 56%

The influence of different cement spaces on the marginal gap of CAD/CAM all‐ceramic crowns

Zhang

Dudley

2019

Australian Dental Journal

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Background: The purpose of this study was to measure the marginal gaps of CAD/CAM all-ceramic crowns constructed using different cement spaces on crown preparations created by undergraduate students. Methods: Twenty-four Columbia model lower left first molars with assessed tapers and reduction volumes (RV) were recruited to receive complete coverage E.max crowns. Three E.max crowns were digitally designed and milled for each crown preparation using three different cement spaces: 50 lm (CS-50), 100 lm (CS-100), 200 lm (CS-200). Each crown was seated onto its original crown preparation and three vertical marginal gap measurements were taken at four locations (mid-buccal, mid-lingual, mid-mesial, mid-distal) using a stereomicroscope. The mean marginal gap (MMG) was calculated for each crown and each individual tooth surface. Results: The MMG was statistically significantly different for each of the three cement spaces (126 lm for CS-50, 89 lm for CS-100, and 75 lm for CS-200) (P < 0.0001). A taper of between 20 and 30°produced the smallest MMG. Insufficient RV caused significantly larger MMGs. The buccal margin had significantly smaller MMGs than all other measured surfaces. Conclusions: The most accurate margins of digitally designed all-ceramic crowns constructed on simulation teeth prepared by undergraduate students were observed when using a 200 lm cement space. Abbreviations and acronyms: BL = bucco-lingual; CAD/CAM = computer-aided design/computer-aided manufacturing; CS = cement space; MD = mesio-distal; MMGITS = mean marginal gaps for individual tooth surfaces; MMG = mean marginal gap; MPa = megapascals; RV = reduction volume.

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Section: Discussionsupporting

confidence: 56%

The influence of different cement spaces on the marginal gap of CAD/CAM all‐ceramic crowns

Zhang

Dudley

2019

Australian Dental Journal

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“…The marginal gaps recorded in the four CAD/CAM ceramic materials assessed in this study were all within the range of clinical acceptance (< 120 µm) 21,22 and the values reached for fracture in all groups were above the ranges recorded for occlusal forces in the posterior region (> 500 N). In light of the data, we failed to reject the null hypothesis concerning the internal fit of the four groups but rejected the null hypothesis with regard to fracture resistance since significantly greater values were recorded for e.max.…”

Section: Resultssupporting

confidence: 58%

Evaluation of the Adaptation and Fracture Resistance of Three CAD–CAM Resin Ceramics: An In vitro Study

Naffah

Ounsi

Özcan

et al. 2019

The Journal of Contemporary Dental Practice

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Aim:The internal fit and resistance to fracture of resin ceramics are to be evaluated compared to that of lithium disilicate as the control group. Materials and methods: Four groups of 20 crowns each (GC Cerasmart, Vita Enamic, Coltène Brilliant Crios, and e.max CAD) were cemented on identical metal dies. Marginal gaps were measured before cementation and load to fracture was applied after cementation, half of each group was thermodynamically aged (3,000 cycles of 5° to 55° immersion followed by 200,000 cycles of 100 N load), finally the crowns were loaded until fracture in a universal testing machine. Statistical package for social sciences (SPSS) package 23 was used for statistical work. Results: Marginal gaps ranged between 68.5 ± 23.8 µm and 87 ± 29.1 µm while occlusal gaps ranged from 220.7 ± 33.3 µm to 275.5 ± 46.5 µm and were not significantly different between groups. Fracture loads ranged from 633.8 ± 127.3 N to 1596.4 ± 497.7 N with lithium disilicate glass ceramics (LDGCs) and Enamic having higher values than resin nano-ceramics (RNCs). The fracture resistance was more related to material than aging and gap value. Conclusion: The margin adaptation of resin ceramics was comparable to lithium disilicate with no significant difference. Lithium disilicate showed a higher resistance than resin ceramics and there was a higher resistance to fracture for polymer-infiltrated ceramic-network (PICN) than RNCs. Clinical significance: Resin ceramics can have marginal adaptation and fracture resistance within clinical acceptance; therefore, they can be a good chair-side solution achieved in a single appointment session.

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“…Studies on the marginal fit of zirconia copings fabricated by CAD-CAM have reported measured marginal discrepancies of as low as 10 μm and as high as 160 μm, with most being less than 80 μm [14–16]. With regard to full zirconia crown, the studies show marginal discrepancies between 11 μm to 58 μm [17, 18].…”

Section: Introductionmentioning

confidence: 99%

“…The marginal fit of zirconia copings produced using different CAD-CAM system has also been investigated [15, 16, 21, 22]. The marginal fit of monolithic zirconia crown was studied with regard to different preparation designs and sintering techniques [17, 18]. However, no studies investigate the effect of different CAD-CAM fabrication methods on the marginal fit of monolithic zirconia crowns; the use of monolithic zirconia crowns is increasing, and therefore a comparison of fabrication methods is justified.…”

Section: Introductionmentioning

confidence: 99%

An in vitro evaluation of marginal fit zirconia crowns fabricated by a CAD-CAM dental laboratory and a milling center

et al. 2019

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Background Marginal fit is critical for the success and longevity of a dental restoration. Zirconia crowns can be fabricated either chair-side, in a dental laboratory or in a milling center; each can give different marginal fits results. However, discussion of the marginal fit of zirconia crowns when different fabrication methods are compared is lacking in the literature. Purpose To compare the marginal discrepancy (MD) and absolute marginal discrepancy (AMD) of computer-aided design, and computer-aided manufacturing (CAD-CAM) used in a dental laboratory and a milling center for producing monolithic zirconia crowns. Methods The marginal fit of 30 zirconia crowns cemented to typodont teeth was evaluated by means of a sectioning technique. Fifteen crowns were fabricated with a CEREC inLAB MC X5 from IPS e.max ZirCAD blocks. Fifteen crowns were fabricated using a LAVA milling center from LAVA Plus Zirconia Blocks. The 30 crowns were sectioned with a precision saw, and MD and AMD were subsequently measured using a light microscope. Data were analyzed using the one-way ANOVA technique to investigate significant differences in the marginal fit between the two fabrication systems (α = .05). Results The AMD dimension of the CEREC inLAB system was significantly smaller ( P < .05). Mean AMD values for zirconia crowns fabricated by the CEREC inLAB were 85 μm, and for the LAVA milling center 133 μm. There was no significant difference between the two systems regarding the MD dimensions. The MD values for zirconia crowns fabricated by the CEREC inLAB were 53 μm and for the LAVA milling center 61 μm. Conclusions The CEREC inLAB system demonstrated significantly better marginal fit in relation to the AMD. However, no difference between the systems was found in the MD. Monolithic zirconia crowns fabricated by the CAD-CAM CEREC inLAB system and the LAVA system milling center showed MD values of less than 120 μm, which is within the clinically acceptable range.

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Marginal and Internal Fit of CAD/CAM Crowns Fabricated Over Reverse Tapered Preparations

Abstract: Under the conditions of this study, the marginal and internal fit of zirconia crowns fabricated over inverse-tapered preparations is within clinically accepted values.

Cited by 15 publications

References 39 publications

The influence of different cement spaces on the marginal gap of CAD/CAM all‐ceramic crowns

The influence of different cement spaces on the marginal gap of CAD/CAM all‐ceramic crowns

Evaluation of the Adaptation and Fracture Resistance of Three CAD–CAM Resin Ceramics: An In vitro Study

An in vitro evaluation of marginal fit zirconia crowns fabricated by a CAD-CAM dental laboratory and a milling center

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