Abstract
Statement of problem
An implemented objective measuring system for measuring clinical tooth preparations
does not exist.
Purpose
The purpose of this study was to compare clinically achieved tooth preparations for
ceramic crowns by general dentists with the recommended values in the literature with
an objective measuring method.
Material and methods
Two hundred thirty-six stone dies prepared for anterior and posterior complete ceramic
crown restorations (IPS e.max Press; Ivoclar Vivadent) were collected from dental
laboratories. The dies were scanned and analyzed using the coordinate geometry method.
Cross-sectioned images were captured, and the average total occlusal convergence angle,
margin width, and abutment height for each preparation was measured and presented
with associated 95% confidence intervals.
Results
The average total occlusal convergence angles for each tooth type was above the recommended
values reported in the literature. The average margin widths (0.40 to 0.83 mm) were
below the minimum recommended values (1 to 1.5 mm). The tallest preparations were
maxillary canines (5.25 mm), while the shortest preparations were mandibular molars
(1.87 mm).
Conclusions
Complete crown preparations produced in general practice do not achieve the recommended
values found in the literature. However, these recommended values are not based on
clinical trials, and the effects of observed shortfalls on the clinical longevity
of these restorations are not predictable.
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Article info
Publication history
Published online: April 06, 2015
Identification
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© 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.
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- Reporting numeric values of complete crowns. Part 2: Retention and resistance theoriesJournal of Prosthetic DentistryVol. 114Issue 1
