RESUMO
Clinical longevity is a primary concern when selecting a restorative dental material. Clinical failure is the point at which the restoration is no longer useful and may pose sever risks if not replaced. The aim of this clinical study was to evaluate the failure in CL II amalgam restorations in operative department of dental school affiliated to Shahid Sadoughi University of Medical Sciences. This was an analytic-descriptive study performed on 69 patients who were previously treated at Yazd dental school and invited to be reexamined for treated teeth. All Patients [220 teeth] with problems in their amalgam restoration were thoroughly examined under appropriate light. Evaluation criteria were direct observation, probing by explorer, dental floss, and radiography. Patients were requested to fill a questionnaire regarding a number of subjective questions and oral hygiene. Objective observations were overhang 25.5%, secondary caries 15%, improper contact 7.3%, fracture 1.4%, improper anatomic form 3.6%, ditch 3.6%, gap 0.4%, and restoration avulsion 0.5%. Regarding the subjective criteria, problems such as food impaction 13.2%, sensitivity to cold 8.2%, sensitivity to heat 5.9%, sensitivity to pressure 3.2%, gingival discomfort 3.2%, spontaneous pain 2.3%, and poor oral hygiene 15.8% were revealed. Although he difference in failure of amalgam restoration among all study groups was shown to be insignificant however, more strict supervision by dental attending concerning the proper implementation of procedures for an ideal restoration is recommended