Influence of convergence angle and cement space on adaptation of zirconium dioxide ceramic copings

Iwai, Takayuki; Komine, Futoshi; Kobayashi, Kazuhisa; Saito, Ayako; Matsumura, Hideo

doi:10.1080/00016350802139833

Cited by 55 publications

(65 citation statements)

References 15 publications

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“…The adaptation of most zirconia-based restorations fabricated with CAD/CAM technology is within the acceptable range for meeting clinical requirements (13)(14)(15)(16)(17)(18). Some basic in vitro studies have evaluated the adaptation of single crown restorations in terms of clinical parameters for tooth preparation.…”

Section: Marginal and Internal Adaptationmentioning

confidence: 99%

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Current status of zirconia-based fixed restorations

2010

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Section: Marginal and Internal Adaptationmentioning

confidence: 99%

“…Increasing the convergence angles of the tooth abutments reportedly improved the internal (16) and marginal (17) adaptation of zirconia-based crowns. Using CAD software, Iwai et al (16) found that computer-fixed cement spaces with might influence the marginal adaptation of zirconia-based crowns.…”

Section: Marginal and Internal Adaptationmentioning

confidence: 99%

Current status of zirconia-based fixed restorations

2010

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“…8 When using light microscopy directly, only the marginal gap width can be determined, 8 and when using a number of prepared teeth and then sectioning the crowns/teeth, the gap width could be influenced by such factors as the design of the prepared teeth. [25][26][27][28] It should be noted, however, that with the replica technique used in the present study the crowns were filled with light-body impression material and held in place with finger pressure. This could have resulted in a variable force applied on the crowns, but the experimental setup imitates the way crowns are usually placed in patients.…”

Section: Discussionmentioning

confidence: 99%

“…Possible explanations for the divergent gap width determined in the three studies could be that the there were slight differences in convergence angle and/or in the finishing margin design of the prepared teeth and/or differences in preparation depth. [25][26][27][28] Regarding the internal fit, internal discrepancies may weaken the ceramic crowns, so the marginal and internal fits are among the important criteria for the long-term success of ceramic restorations. For example, because the space between the tooth and the restoration exposes the luting material to the oral environment, a wide gap discrepancy may cause cement solubility, plaque accumulation, marginal leakage, and crown failures.…”

Section: Discussionmentioning

confidence: 99%

Accuracy of Ceramic Restorations Made Using an In-office Optical Scanning Technique: An In Vitro Study

Tidehag

Ottosson

Sjögren

2014

Operative Dentistry

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The findings in the present study suggest that in-office digital impressions and subsequent computer-aided design/computer-aided manufacturing (CAD/CAM) fabrication of ceramic crowns could result in marginal and internal fit similar to that of hot-pressed all-ceramic crowns. SUMMARYThe present in vitro study concerns determination of the pre-cementation gap width of all-ceramic crowns made using an in-office digital-impression technique and subsequent computer-aided design/computer-aided manufacturing (CAD/CAM) production. Two chairside video camera systems were used: the Lava Oral scanner and Cadent's iTero scanner. Digital scans were made of a first molar typodont tooth that was suitably prepared for an all-ceramic crown. The digital impressions were sent via the Internet to commercial dental laboratories, where the crowns were made. Also, an impression of the typodont tooth was made, poured, and scanned in order to evaluate the pre-cementation gap of crowns produced from scanning stone dies. These methods and systems were evaluated by creating replicas of the intermediate space using an addition-cured silicone, and the gap widths were determined using a measuring microscope. Hot-pressed leucite-reinforced glassceramic crowns were selected as a reference. The mean value for the marginal measuring points of the control was 170 lm, and the values for all the evaluated crowns ranged from 107 to 128 lm. Corresponding figures for the internal measuring points were 141-210 lm and 115-237 lm, respectively. Based on the findings in the present study, an in-office digital-impression technique can be used to fabricate CAD/CAM ceramic single crowns with a marginal and internal accuracy that is on the same level as that of a conventional hot-pressed glass-ceramic crown. In the pre-

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“…3,4,[6][7][8] Vertical gaps may be introduced during either fabrication step, including during computer-aided design (CAD)/ computer-aided manufacturing (CAM) digitization. 9 Hence, since both the scanning technique 7,9 and the preparation design [10][11][12] may play an important role in the clinical success of the denture, different preparation angles can be evaluated to test the accuracy of different CAD/CAM systems.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of fit of zirconia posterior bridge structures constructed with different scanning methods and preparation angles

2010

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This study evaluated the influence of scanning method, abutment position, and preparation angle on the vertical seal of three-unit posterior zirconia structures. Sixty differently angled metallic models were machined to receive 30 bridge frameworks. For each preparation type, half of the structures were waxed-up and digitized, whereas the other half were computer-designed after the abutments were scanned. Once milled, the samples were cemented in standard fashion. Misfit was assessed by scanning electron microscopy. Three-way analysis of variance showed significant differences. Computer-designed structures achieved the highest accuracy (P< 0.0001). No significant differences were recorded concerning the abutment position and convergence angle. All discrepancy values were within the clinically acceptable range.

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Influence of convergence angle and cement space on adaptation of zirconium dioxide ceramic copings

Cited by 55 publications

References 15 publications

Current status of zirconia-based fixed restorations

Current status of zirconia-based fixed restorations

Accuracy of Ceramic Restorations Made Using an In-office Optical Scanning Technique: An In Vitro Study

Evaluation of fit of zirconia posterior bridge structures constructed with different scanning methods and preparation angles

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