Placement and reasons for failure of amalgam versus composite posterior restorations for patient attending to dental school

Objective: The aim of this study is to assess the prevalence of distribution of posterior amalgam and composite restoration and to register various reasons for replacement or repair of amalgam or composite restorations of patients visiting a dental school.
Materials and Methods: A cross sectional study on 635 patients aged 17 years and above, visiting School of Dentistry, Faculty of Medical Sciences/University of Sulaimani was carried out over a period of 6 months. These patients were examined clinically and radiographically to determine the choice of direct amalgam and composite restorative material for restorations of teeth and to find out the reasons of the failed amalgam or composite restorations which needed replacement or repair.
Results: The results of the present study revealed that the sample group comprised of 334 males and 301females, it was concluded that the Amalgam (65.52%)) was the most frequently used restorative material. This was followed by resin composite (34.48%). Seven reasons were found responsible for replacement or repair of restorations; Secondary caries was the most prevalent reason for replacement or repair of both amalgam (32.54%) and composite (54.7%).
Conclusion: It was concluded that amalgam was the most chosen direct restorative material and the majority of restorations were placed in class I and II preparations in lower molar.  Secondary caries was the most common reason for repairing or replacing existing restorations.