TITLE:
Assessment of undergraduate students’ tooth preparation for full veneer cast restorations
AUTHORS:
Nuha El-Mubarak, Neamat Abu-Bakr, Osama Omer, Yahia Ibrahim
KEYWORDS:
Fixed Prosthodontics; Tooth Preparation; Finish Lines; ImpressionsFixed Prosthodontics; Tooth Preparation; Finish Lines; Impressions
JOURNAL NAME:
Open Journal of Stomatology,
Vol.4 No.2,
February
6,
2014
ABSTRACT: Purpose:
To evaluate tooth preparation for full veneer cast restorations performed by
final year dental students in Sudan. Materials and Methods: 117 stone dies from two different dental institutions were
collected and evaluated. Polyvinylsilioxane impression material was used to
produce two impressive replicas of which one was sectioned in faciolingual
plane and the other in mesiodistal plane. Occlusal clearance was measured using
a digital caliper. Amount of axial preparation was also measured. Impression
silhouettes that were produced using an overhead projector were used to measure
convergence angle. Working casts were examined for smoothness and evenness of
the preparations, existence or absence of additional features of retention
and the finishing line were evaluated for its position and continuity. All
obtained data were statistically analyzed by using T-test, ANO-VA, and Pearson
Chi square tests. P-values ≤ 0.05 were considered as statistically significant.
Results: Average taper of the examined preparations was 39.98?, with 44.1? in
the faciolingual, and 35.8? in the mesiodistal dimensions. Preparations for
full coverage restorations were over prepared. 38.5% of the total number of
preparations were found to have finishing lines in the sub and supra gingival
positions. 19.66% were unable to maintain continuity of the finishing line all
around the preparation. All preparations were generally smooth with no sharp
angles, and 1.7% of the preparations had additional retentive features. Conclusion:
Within the limitations of this study, it could be concluded that the
convergence angle and finishing line preparations were less than adequate in
a sizeable proportion of the preparations examined.