Stig Lavstedt

Proximal alveolar bone loss in a longitudinal radiographic investigation: IV. Smoking and some other factors influencing the progress in individuals with at least 20 remaining teeth

In Sweden people in all age groups now have more remaining teeth than previously. An investigation has been made to identify some predictors of alveolar bone loss in a 10-year period in subjects with at least 20 remaining teeth. The material consisted of 349 individuals, examined radiographically, clinically, and by interview in 1970 and in 1980. These subjects, born in 1904-1952, constituted a subgroup, with regard to remaining teeth, of an unselected sample of the population of the old county of Stockholm. In the unselected sample statistically significant predictors of alveolar bone loss found in a stepwise multiple regression analysis were alveolar bone loss in 1970, age, number of lost teeth, and Russells Periodontal Index (PI). In the subgroup the predictors were in the order Russells PI and smoking. The prediction values (R2) of further variables were marginal. The analyses showed that there was an interaction between PI and smoking, implying that the effect of smoking on alveolar bone loss was increased in individuals with high PI values. Furthermore, a tendency was found for a dose-response effect of tobacco consumption. This tendency almost disappeared when controlling for PI.

Proximal alveolar bone loss in a longitudinal radiographic investigation: II. A 10-year follow-up study of an epidemiologic material

Four hundred and six individuals from an unselected sample from the County of Stockholm aged 18-65 years in 1970 were examined radiographically in 1970 and 1980. The differences in proximal alveolar bone height were recorded, attention being paid to the divergences in projection between the two investigations. The mean of the alveolar bone difference was 5.5% of the mean root length, which corresponds to an average annual bone loss of 0.09 mm. Ninety per cent of the individuals had a difference in alveolar bone height of less than 10% of the root length--that is, an average bone loss of 1.6 mm or less during 10 years. By linear regression analysis it was shown that the difference in alveolar bone height is a function of the initial bone loss; that is, the greater the initial bone loss, the greater the alveolar bone loss during the 10-year period. The result of the regression analysis may facilitate predictions of alveolar bone loss.

A computerized system to measure interproximal alveolar bone levels in epidemiologic, radiographic investigations: II. Intra-and inter-examiner variation study

The study was aimed at analyzing intra- and inter-examiner variations in computerized measurement and in non-measurability of alveolar bone level in a cross-sectional, epidemiologic material. At each interproximal tooth surface, alveolar bone height in percentage of root length (B/R) and tooth length (B/T) were determined twice by one examiner and once by a second examiner from x5-magnified periapical radiographs. The overall intra- and inter-examiner variations in measurement were 2.85% and 3.84% of root length and 1.97% and 2.82% of tooth length, respectively. The variations were different for different tooth groups and for different degrees of severity of marginal periodontitis. The overall proportions of non-measurable tooth surfaces varied with examiner from 32% to 39% and from 43% to 48% of the available interproximal tooth surfaces for B/R and B/T, respectively. With regard to the level of reliability, the computerized method reported is appropriate to cross-sectional, epidemiologic investigations from radiographs.

A computerized system to measure interproximal alveolar bone levels in epidemiologic, radiographic investigations: I. Methodologic study

The aims of the study were to adapt a computerized system to epidemiologic conditions, for rapid full-mouth measurements of alveolar bone levels from X5-magnified periapical radiographs and to analyze the variations in measurement due to different system components. Full-mouth measurements of interproximal alveolar bone height in percentage of root and tooth lengths were completed within an average time of 15 min per set of radiographs. An analysis of variance showed that the examiner variation in measurement of a linear scale distance was 0.02 mm. The measurement accuracy was different for different distances; each distance (d) measured with this system should therefore be calibrated with the equation Y = -0.007-0.014 (log3d-1.50), where Y is the estimate of measurement accuracy. The present computerized system enabled rapid recordings and demonstrated good measurement precision and accuracy; these are valuable features in epidemiologic investigations.

Proximal alveolar bone loss in a longitudinal radiographic investigation I. Methods of measurement and partial recording

A longitudinal radiographic investigation was made of the progression of the proximal alveolar bone loss over a 10-year period (1970-1980). The material was unselected and consisted of 669 individuals in the county of Stockholm. Sixty-one individuals were randomly selected for evaluation of a recording system using alternative methods of measurement, and 90% of the measurement sites could then be assessed. The correlations between some of the methods were high, such as between measurement of alveolar bone height and root length and between alveolar bone height and tooth length. To reduce the number of measurements, a partial recording was made, giving a high correlation coefficient between the partial recording and total recording. When five measurement sites (12 m, 11 m, 33 d, 31 d, 41 m) were were used, the correlation coefficient was 0.96, and a slight increase of the coefficient was obtained when using additional sites.