[Periodontal disease and occlusal trauma: a still debated controversy? A review of the literature].

In the "Glossary of Periodontics Terms" written by the American Academy of Periodontology, the occlusal trauma is defined as "an injury to the attachment apparatus as a result of excessive occlusal forces". Nowadays, the effects of occlusal trauma on tooth support tissues, the onset and the progression of periodontal disease are still debated: many commonplaces have been disproved, but some doubts and not yet clear points remain, even owing to the difficult diagnosis of the presence and the real clinical impact of a traumatic occlusion. Then, ethical reasons prevent researchers from prospective clinical trials. At the beginning of the last century occlusal trauma has been supposed to be an etiologic factor of "alveolar pyorrhea", but several studies attending more strict scientific criteria failed to prove such correlation. On the basis of the bacterial genesis of periodontal disease, researchers started evaluating the possible effects of occlusal discrepancies on incidence, progression and treatment outcomes of periodontitis, but all the results underlined the more relevant role played by micro-organisms. The present review of the literature runs through this controversy again, analysing the most significant studies published.