Etiology of periodontal diseases.

Periodontal diseases are a series of complex, distinct, pathologic entities caused by the interaction of bacterial plaque and the host. This interaction results in destruction of the supporting alveolar bone and connective tissue. Although bacterial plaque has been implicated as the primary etiologic agent in most forms of periodontal disease, there are local and systemic factors which may modify both microbial and host components. Local factors may favor plaque accumulation and maturation, while systemic factors may modulate and decrease the host's protective response.