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The purpose of this study was to assess the prevalence of A. actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia, and their association with periodontal disease states in a population sample from Sri Lanka. Based on clinical parameters, a total of 536 sites in 268 male Sri Lankan tea workers were categorized as healthy, or showing gingivitis only, moderate or advanced periodontitis. Bacterial samples were obtained from all sites and the three target bacteria identified by indirect immunofluorescence. P. intermedia, P. gingivalis and A. actinomycetemcomitans were found in 76%, 40% and 15% of the subjects, respectively. Of the 536 periodontal sites, 10.5% were categorized with "no disease", 14% "gingivitis only": 59% with moderate and 16% with advanced periodontitis. The prevalence of P. gingivalis and P. intermedia was significantly higher in sites with moderate and advanced periodontitis than in sites with no disease or gingivitis only. A. actinomycetemcomitans was not found in healthy sites, but occurred with equal frequency in sites with gingivitis, moderate and advanced periodontitis. The association between these three bacteria and periodontal diseases in Sri Lankan tea laborers was similar to that described for other non-industrialized and industrialized countries.

This paper describes the initiation, rate of progress of periodontal disease and consequent tooth loss in a population never exposed to any programs or incidents relative to prevention and treatment of dental diseases. The group consisted of 480 male laborers at two tea plantations in Sri Lanka. The study design and baseline data have been published. At the initial examination in 1970, the age of the participants ranged between 14 and 31 years. Subsequent examinations occurred in 1971, 1973, 1977, 1982 and 1985. Thus, the study covers the age range 14-46 years. Throughout the study, the clinical indices were scored by the same two examiners, both well-trained and experienced periodontitis. Intra-examiner reproducibility for each index was tested at baseline and repeated periodically during the study. The data for each examination were computerized and updated on an ongoing basis. At the last examination in 1985, there were 161 individuals who had participated in the first survey. This population did not perform any conventional oral hygiene measures and consequently displayed quite uniformly large aggregates of plaque, calculus and stain on their teeth. Virtually all gingival units exhibited inflammation. Based on interproximal loss of attachment and tooth mortality rates, three subpopulations were identified: (1) individuals (approximately 8%) with rapid progression of periodontal disease (RP), those (approximately 81%) with moderate progression (MP), and a group (approximately 11%) who exhibited no progression (NP) of periodontal disease beyond gingivitis. At 35 years of age, the mean loss of attachment in the RP group was approximately 9 mm, the MP group had approximately 4 mm and the NP group had less than 1 mm loss of attachment. At the age of 45 years, the mean loss of attachment in the RP group was approximately 13 mm and the MP group approximately 7 mm. The annual rate of destruction in the RP group varied between 0.1 and 1.0 mm, in the MP group between 0.05 and 0.5 mm, and in the NP group between 0.05 and 0.09 mm. Since this population was virtually caries free, essentially all missing teeth were lost due to periodontal disease. In the RP group, tooth loss already occurred at 20 years of age and increased throughout the next 25 years. At 35 years of age, 12 teeth had been lost, at 40 years of age 20 teeth were missing and at 45 all teeth were lost. In the MP groups, tooth mortality started after 30 years of age and increased throughout the decade.(ABSTRACT TRUNCATED AT 400 WORDS)

This longitudinal study of randomly selected Norwegian students and academicians has shown that 50% of the 17-year olds have lost no periodontal support, and the other 50% exhibited slight localized loss of attachment primarily on buccal surfaces of first molars and first bicuspids of both jaws. At 21 all students show one or more of these lesions as well as loss of attachment on interproximal surfaces. At 30 years of age the mean cumulative loss is still less than 1 mm. As they approach 40 years of age the mean individual loss of attachment is slightly above 1.5 mm or 10% of the total periodontal support, and the mean annual rate of attachment loss is 0.08 for interproximal surfaces and 0.1 mm for buccal surfaces. No case of juvenile periodontitis (periodontosis) or adult aggressive periodontitis were seen in this population. Seventy percent of the 15-year-old Sri Lankans have no or very little loss of periodontal support. However, approximately 30% exhibit localized lesions measuring between 2 and 9 mm and more than 1% have one or more root surfaces with 10 mm loss of attachment or more. In this age group the lesions occur at the interproximal and buccal aspects of lower central incisors and in first molars of both jaws. At 30 years of age the mean loss of attachment is 3.11 mm and approximately 25% of the tea laborers have lesions extending 10 mm or more below the cemento-enamel junction. As the Sri Lankan approaches 40 years of age the mean loss of attachment is 4.50 mm and the mean rate of progress of the lesion is 0.20 mm per year for buccal surfaces and 0.30 mm for interproximal surfaces. This study suggests that without interference the periodontal lesion progresses at a relatively even pace and that the progress is continuous.