Résumé
Overdentures have gained high popularity in the last ten years as an alternative to complete dentures for patients with remaining natural teeth. The advantages of over denture were recorded as preserving the residual alveolar ridge, as well as increased masticatory performance due to the proprioceptive impulses from over denture abutments. [Lord and Teels., 1974 and Rissin et al., 1987]Many techniques for overdenture construction were used, but the most common techniques were that one constructed over reduced abutments with amallgum filling or over reduced abutments with cast metal or gold copings. The loss of abutments of the overdenture was the prime etiologic factor in overdenture failure, and that loss was often due to periodontal disease affecting the abutments. A question arise, dose the restorations for abutments of over dentures have an effect on the subgingival micro flora. The present work aims to study the effect amalgam and coping restoration of the abutments of overdenture on subgingival micro flora as well as the count of subgingival Bacteroides melaninigenicus