Changing concepts. The effects of occlusion on periodontitis.
Despite volumes of publications on the theory of occlusion, occlusal design, and equilibration techniques, there have been few well-designed human studies directed at answering the question does occlusal trauma modify the progression of attachment loss in periodontitis. The articles reviewed indicate that occlusal forces can cause changes in the alveolar bone and periodontal connective tissue both in the presence and in the absence of periodontitis. These changes can affect tooth mobility and clinical probing depth. Although occlusal forces do not initiate periodontitis, results are inconclusive as to if or how these forces affect attachment loss owing to plaque-induced inflammatory periodontal disease. Although some studies reported a relationship between increased attachment loss and tooth mobility, others found no relationship between attachment loss and abnormal occlusal contacts. Tooth mobility results from a variety of factors, including alveolar bone loss, attachment loss, disruption of the periodontal tissues by inflammation, widening of the PDL in response to occlusal forces (physiologic adaptation), PDL atrophy from disuse, and other processes that effect the periodontium. Therefore, any relationship found between tooth mobility and progressing periodontitis does not necessarily implicate or defend occlusion as a cofactor in the progression of inflammatory periodontal disease. Periodontitis can be treated and periodontal health maintained without occlusal adjustment and in the presence of traumatic occlusal forces. Statistically greater gains in clinical periodontal attachment level have been reported, however, when occlusal adjustment was included as a component of periodontal therapy. The extent to which this is clinically meaningful is unclear. Once periodontal health is established, occlusal therapy can be used to reduce mobility, to regain bone lost owing to traumatic occlusal forces, and to treat a variety of clinical problems related to occlusal instability and restorative needs. The clinician's decision whether or not to use occlusal adjustment as a component of periodontal therapy should be related to an evaluation of clinical factors involving the patient's comfort and function and not based on the assumption that occlusal adjustment is necessary to stop the progression of periodontitis.