Thorough evaluation of all structures that might contribute support to a prosthesis must certainly include natural teeth, since their number, location in the arch, individual position, mobility, vitality, crown-to-root ratio, root size and shape, susceptability to caries and pathologie involvement. One of the most important observations affecting treatment planning involves the condition of the occlusal plane of the remaining natural teeth. The use of periodontally weakened teeth as abutments is often debated but the prognosis of periodontal therapy and thus the possibility of using periodontally diseased teeth for prosthesis include: 1. The extention of the disease involvement. 2. Duration and progression. 3. Causative factors, including occlusal, bone level, pocket-dept and furcation involvement and 4. Attitude, cooperation and determination to provide home care. The development and the maintenance of bacterial plaque on the teeth is considered as a primary factor that causes inflammation and effects the Biological future of fixed prosthesis.