Background: Clinical observations and epidemiologic studies suggest that some negative life events and psychological factors may contribute to an increased susceptibility to periodontal disease. The aim of the present study was to systematically review the evidence from case-control studies, cross-sectional studies, and prospective clinical trials reporting on the influence of stress and psychological factors on periodontal disease. The focused question addressed in this systematic review was whether the scientific evidence is enough to consider stress and psychological factors as risk factors for periodontal disease.
Methods: A literature search was conducted using two databases (MEDLINE and the Cochrane Oral Health Group specialist trials register) in addition to searching reference lists of original and review articles. The search strategy used was the combination of the terms: "stress," "periodontal disease," and "psychosocial disorders." Studies were selected if they were published in dental journals between January 1, 1990 and April 1, 2006; only human studies and studies with adults and middle-aged subjects were included. Suitable variables included control for the potential effect of confounding factors, adequate criteria to define periodontal disease, adequate criteria for establishing stress, and methodologic quality. Only English-language articles were considered, and unpublished data were not sought. Two reviewers independently extracted information regarding quality and study characteristics in duplicate. The studies were assessed regarding their methodologic characteristics, statistical analysis, characteristics of the periodontal outcome measures, and psychological measurements.
Results: Of the 58 articles identified in the search, 10 were excluded because they were reviews and 34 did not comply with the selection criteria. Fourteen articles (seven case-control studies, six cross-sectional studies, and one prospective clinical trial) were included in the analysis; their quality and main study characteristics were assessed according to the criteria preestablished in the protocol of the study. With regard to the results of the studies, 57.1% found a positive outcome between psychosocial factors/stress and periodontal disease, 28.5% observed a positive outcome for some characteristics and a negative outcome for others, and 14.2% found a negative outcome.
Conclusions: Within the limitations of this systematic review, the majority of studies showed a positive relationship between stress/psychological factors and periodontal disease. However, in the future, well-designed and more representative studies should be considered to confirm these factors as a risk for periodontal disease.