During the three previous decades the etiology and pathogenesis of gingivitis and periodontitis has been studied by a variety of techniques. Microbiological, cell biological, molecular biologyl and clinical methods have been employed. Taken together the results from these studies and experiences show beyond doubt that periodontal attachment loss is caused by subgingival colonization of oral microorganisms. The infection is of opportunistic character even if certain oral bacteria seem to be more important as periodontopathogenes than others. Longitudinal studies in humans have shown that elimination of the supra- and subgingivally located bacteria reduce the symptoms gingival inflammation and periodontal pathology. Such treatment procedures lead to that further progression of periodontal attachment loss can bereduced and/or prevented.Periodontal diseases are treated with what is called non-surgical and surgical methods.

The difference between these two treatment procedures is however limited. The procedure called non-surgical periodontal therapy includes actually an unintentional removal of the pocket epithelium and an uncontrolled removal of varying parts of the connective tissue lateral to the pocket epithelium. The surgical treatment aims at elimination of pathology either by a resective technique: gingivectomy or a by a flap procedure. The difference between non-surgical and surgical treatment methods is more quantitative than qualitative. Recently, techniques for regeneration of lost periodontal attachment has been developed. However, this far these latter procedures do not result in a predictable result. In some patients excellent regeneration is achieved while in others there is limited effect of the regenerative treatments. The difference in results of regenerative treatment might relate to variations in the cleaning of the root surfaces and the postoperative control of bacterial recolonization. Long term success of periodontal treatment has been demonstrated in patients who maintain a good oral hygiene level and recieve supportive treatments at regular intervals.