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PubMed · 12892452

Ensuring retention for crowns and fixed prostheses.

Gordon J Christensen
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Abstract

Crowns and fixed prostheses are well-proven, accepted and routinely used restorations. However, they occasionally come loose from tooth preparations. Many things can cause these failures. In this article, I have discussed the following reasons for lack of adequate retention of crowns and fixed prostheses: inadequate tooth preparation; too much trust in dentin bonding agents and lack of adequate tooth buildup; tooth preparations that lack irregularities; improper selection of cements; and lack of postoperative occlusal adjustment.

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CrownsDental BondingDental CementsDental Prosthesis RetentionDental Restoration FailureDenture RetentionDenture, Partial, FixedHumansOcclusal AdjustmentSurface PropertiesTooth Preparation, ProsthodonticJournal Article

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Gordon J Christensen. 2003. Ensuring retention for crowns and fixed prostheses.. https://doi.org/10.14219/jada.archive.2003.0293

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PubMed2006

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PubMed2006

Assessment of the amount of remaining coronal dentine in root-treated teeth.

OBJECTIVES: There is currently no standardised technique to measure the amount of coronal dentine remaining in a root-treated tooth after crown preparation. The aim of this study was to develop a method of measuring remaining coronal dentine in root-treated teeth and to propose an index for grading tooth restorability. METHODS: The study recruited 20 patients who had completed molar endodontic treatment at the Eastman Dental Hospital and had been prescribed an amalgam coronal-radicular core with a full coverage cast restoration. Using a series of interlocking special trays and impressions, a method was devised to produce a cast of the amount of remaining dentine coronal to the finish line after crown preparation. This cast was scanned using a laser profilometer and the volume of remaining dentine was calculated. A tooth restorability index (TRI) was developed to assess the strategic value of the remaining dentine. The TRI allowed scores of 0-3 in each sextant with a maximum score of 18 per tooth. RESULTS: Twenty teeth were scored by three examiners and the TRI scores varied from 2 to 13. The volume of coronal dentine varied from 61.73 to 232.22 mm(3). CONCLUSIONS: A tooth restorability index has been devised to assess the strategic value of remaining dentine. A Kappa statistic was calculated to produce values of 0.584, 0.688 and 0.720, giving moderate-good agreement between the examiners.

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