Natural history of periodontal disease in man. Rapid, moderate and no loss of attachment in Sri Lankan laborers 14 to 46 years of age

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)