A SEM STUDY TO DETERMINE OCCLUSAL MARGINAL ADAPTATION OF DENTAL AMALGAM AND COMPOSITE RESIN RESTORATIVE MATERIALS LINKED TO INSTRUMENTATION AND THE HANDLING OF THESE MATERIALS

Objectives: SEM to determine occlusal adaptability and damage to tooth structure after finishing and polishing of 2 restorative materials: Non-gamma 2 high-copper dental amalgams and hybrid composite resins.

Methods: Forty Class I occlusal cavities of uniform size were prepared following Black’s principles on extracted human premolars. These were divided into groups A and B (20 specimens each). Group A: Fife cavities were restored with non-gamma 2 high copper amalgam using a HU-FRIEDY condenser, manipulated either with ball burnisher or excavator. Fifth teen cavities were restored with hybrid composites, manipulated either with ball burnisher, flat plastic or comporoller. In Group B cavity preparations/ restorations mimicked group A. However, the 5 amalgam restorations were polished using amalgam finishing burs and the 15 hybrid composite restorations were trimmed and polished with Dura-White stones and the Enhance system. All specimens were mounted on a metallic slab, dehydrated, gold-palladium sputter-coated and viewed under SEM at 15-30x Kv5 magnification.

Results: Group A: Amalgam restorations revealed no original cavo-surface margins, over extensions and loose/granular amalgam pieces. Hybrid composite restorations revealed no original cavo-surface margins, over-extensions and loose pieces in the fissures. The comporoller created pores and untidiness.
Group B: Polished amalgams revealed visible pitted cavo-surface margins. Polished hybrid composite restorations revealed visible cavo-surface margins in some areas, over-extension of resin material, and damage to surrounding enamel.
Conclusions: It is difficult to achieve an acceptable marginal adaptation of a dental material, even when adhering to the methods and principles of placement, finishing and polishing.