Fitting accuracy and fracture resistance of crowns using a hybrid zirconia frame made of both porous and dense zirconia

Nakamura, Takashi; Sugano, T.; Usami, Hirofumi; Wakabayashi, Keiji; Sekino, Tohru; Yatani, Hirofumi

doi:10.4012/dmj.2014-145

Cited by 7 publications

(2 citation statements)

References 24 publications

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“…These approaches include direct view technique using external microscope, cross‐sectioning, replica technique, profile projector, and microtomography . However, most of the studies have assessed the marginal fit of zirconia prostheses with external microscopes and the internal fit with either internal microscopes or replica technique . In this study, we measured the marginal gaps by optical microscope due to its non‐destructive nature, feasibility, and practicality.…”

Section: Discussionmentioning

confidence: 99%

Marginal Discrepancies of Monolithic Zirconia Crowns: The Influence of Preparation Designs and Sintering Techniques

Ahmed

Abdallah

McCullagh

et al. 2019

Journal of Prosthodontics

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Purpose The marginal fit is an essential component for the clinical success of prosthodontic restorations. The aim of this study was to investigate the influence of different abutment finish line widths and crown thicknesses on the marginal fit of zirconia crowns fabricated using either standard or fast sintering protocols. Materials and Methods Six titanium abutments were fabricated for receiving zirconia molar crowns. Crowns were designed virtually and milled from partially sintered zirconia blanks and divided into 12 groups (n = 10/group). Crowns in groups 1 to 6 were sintered by standard sintering, while those in groups 7 to 12 were sintered by fast sintering. Groups were further categorized according to abutment finish line and crown thickness: G1/G7 (0.5 mm chamfer, 0.8 mm thick); G2/G8 (0.5 mm chamfer, 1.5 mm thick); G3/G9 (1.0 mm chamfer, 0.8 mm thick); G4/10 (1.0 mm chamfer, 1.5 mm thick); G5/G11 (1.2 mm chamfer, 0.8 mm thick); G6/G12 (1.2 mm chamfer, 1.5 mm thick). The marginal gaps were assessed at 8 locations using digital microscopy. The linear mixed effect model analysis was performed at a significance level of 0.05. Results All vertical marginal gaps were within the clinically acceptable range (∼11‐52 μm). G8 (FS, 0.5 mm chamfer, 1.5 mm thick) demonstrated the largest gaps (47.95 μm, 95% CI: 44.57‐51.23), whereas G3 (SS, 1.0 mm chamfer, 0.8 thick) had the smallest marginal gap (14.43 μm, 95% CI: 11.15‐17.71). A linear mixed effect models showed significant differences for the interaction between finish line × crown thickness × sintering (F = 18.96, p < 0.001). The lingual surfaces showed the largest gaps in both sintering protocols, while the mesial and mesiobuccal surfaces demonstrated the smallest gaps. Conclusions There was a significant interaction between finish line widths, crown thickness, and sintering protocol on the marginal gaps in both sintering protocols; 1.0 mm finish line preparations with either 0.8 mm or 1.5 mm occlusal reduction had better marginal fit in both sintering protocols compared to 0.5 mm or 1.2 mm finish lines. Smaller marginal discrepancies were observed for standard sintering crowns with a 0.5 mm finish line and 1.5 mm occlusal reduction. Conservative occlusal reduction should be accompanied with a 1.2 mm finish line to obtain better marginal fit for full‐contoured zirconia crowns.

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Section: Discussionmentioning

confidence: 99%

Marginal Discrepancies of Monolithic Zirconia Crowns: The Influence of Preparation Designs and Sintering Techniques

Ahmed

Abdallah

McCullagh

et al. 2019

Journal of Prosthodontics

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“…2) Effect of type of material and presence of water 28) , processing could be performed in a short period of time. On the other hand, because of the high standard deviation, that is, the large amount of variability, it will be necessary to investigate the precision with regard to porous materials.…”

Section: ) Evaluation Of Cavity Formationmentioning

confidence: 99%

Processing of Ceramic Blocks Using Femtosecond Lasers

Kitao¹,

Matsubara

Kakimoto

et al. 2016

J. Jpn. Soc. Laser Dent.

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Recently, ceramics has rapidly gained in popularity among dental restorative materials 1) because of increased desire for aesthetics, improvements in materials, and development of computer aided design/computer aided manufacturing (CAD/CAM) systems. Zirconia is the most frequently used material for all-ceramic crowns owing to its overwhelmingly high fracture toughness 2-3). Zirconia crowns are processed either by cutting completely-sintered materials with a cutting tool, or by cutting semi-sintered crowns and then completely sintering. Although the former method yields better processing precision, the latter is widely adopted because of its ease. To process completely sintered zirconia, the use of a laser instead of a mechanical cutting tool has been considered, and processing using a pulsed nanosecond Nd:YVO4 laser has been reported 4). However, the pro

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Fit of tooth‐supported zirconia single crowns—A systematic review of the literature

Ahmed

Shariati

Gazzaz

et al. 2020

Clinical & Exp Dental Res

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Purpose The purpose of this study is to systematically map all the factors that influence the fit and adaptation of zirconia crowns and/or copings. Materials and methods The investigational strategy involved carrying out an electronic search between December 1, 2009 and September 1, 2019 through the Embase and Medline databases using Boolean operators to locate appropriate articles. Results A total of 637 articles were discovered after the removal of duplicates, and 46 of these were selected for evaluation. Further, a quality assessment was performed using GRADE evaluation criteria. Conclusions Shoulder finish line preparations had slightly better marginal fit compared to chamfer finish lines. Crowns obtained from digital impressions had comparable to superior marginal adaptation compared to conventional impressions. Increasing cement space showed to improve zirconia crown adaptation. Cementation and veneering zirconia frameworks found to increase the marginal and internal gaps. Limited information is available on the effect of the alteration of sintering time/Temperature and/or sintering techniques on the adaptation of zirconia crowns. Most of the selected studies had a moderate quality assessment evaluation. Future studies could investigate the chair‐side, ultra‐fast sintering effect on the marginal gap of zirconia crowns.

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Fitting accuracy and fracture resistance of crowns using a hybrid zirconia frame made of both porous and dense zirconia

Cited by 7 publications

References 24 publications

Marginal Discrepancies of Monolithic Zirconia Crowns: The Influence of Preparation Designs and Sintering Techniques

Marginal Discrepancies of Monolithic Zirconia Crowns: The Influence of Preparation Designs and Sintering Techniques

Processing of Ceramic Blocks Using Femtosecond Lasers

Fit of tooth‐supported zirconia single crowns—A systematic review of the literature

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