Margin width, internal line angle and labial emergence profiles of maxillary metalloceramic crowns.
- Author:
N.A. Yahya
;
C.C. Youngson
- Publication Type:Journal Article
- Keywords:
emergence profile;
crown preparation;
shoulder width
- From:
Annals of Dentistry
2007;14(1):7-13
- CountryMalaysia
- Language:English
-
Abstract:
The purpose of this study were to compare the
emergence profiles of crowns with their contralateral
tooth, in vitro, and to determine if there is any
association between the design of tooth preparations
and the resultant emergence profile. 50 working
models used for single crown construction were
examined. Measurements of the faciolingual width
of the crowns and contralateral teeth were taken
using digital calipers. Internal line angles and the
margin width of dies and the emergence profile of
the corresponding crowns were measured from
longitudinally sectioned polyvinylsiloxane indices
mounted on a flat-bed scanner using image analysis
software. Using Students t tests, no statistically
significant differences (p>0.05) were found for
shoulder width (mean 0.94 ± 0.23mm), internal line
angle (mean 105.83 ± 13.57°) or emergence profiles
(28.56 ± 12.95°) in the different (anterior, premolar
or molar) preparations or crowns. The mean
emergence profiles for all crowns was statistically
significantly greater (p<0.001) than the contralateral
tooth (mean 15.33 ± 7.77°). Using linear regression,
there was a weak statistical relationship between
emergence profile and margin width (Emergence
profile° = 31.352 – 2.973 x margin width (mm)).
There was no statistical association between the
internal line angle and the resultant emergence
profile. In conclusion, the emergence profiles of
crowns were higher than the contralateral teeth.
Maxillary metalloceramic crown preparations had
shoulder widths that did not conform to
recommendations in standard texts but line angles
were within a satisfactory range. The margin width
exerts a weak effect upon the emergence profile of
the crown.
- Full text:W020150904318095594847.pdf
