Variations in cervical preparations for metal-ceramic crowns in undergraduate dental students.

Abstract

Objective. This study aims to evaluate the characteristics of the finish line of dental abutments made by fourth year dental students in during clinical practice in prosthodontics. Materials and methods. Eighty preparations were evaluated on working cast. All preparations were made for the application of porcelain fused to metal (PFM) crown, with non-noble metal framework. Aspects of the preparations were quantified and compared with accepted criteria defined following a review of the literature. Results. The teeth found to be most frequently prepared for PFM crowns were premolars and molars (lateral group) (80,74%). Six percent of samples presented a shoulder finish line while a chamfer margin design was noticed in 62,6%. Thirty-one percent of samples had either a feathered or no clear margin design respectively. Of the cervical preparations analyzed, 86% had been underprepared, mostly on the oral and distal surfaces. A significant difference was observed between cervical preparations on molars (preparation width ≤ 0,5 mm), comparing to premolars (preparation width ≥ 0,5 mm). Conclusion. On the evidence of this survey of this sample of undergraduate dental students, it was found that relevant guidelines for the preparations of PFM crown are not being fully adhered to.