The relation between tooth eruption and alveolar crest height in a human skeletal sample.

It is commonly assumed that alveolar crest height increases with continuing tooth eruption unless affected by marginal inflammation. To test this hypothesis, the relation between eruption and alveolar crest height was examined in skulls from a sample consisting of the remains of 244 individuals from the late medieval period. The mandibular first and second molars and second premolars were analysed. The age of the skulls was determined on the basis of dental development and molar attrition. Radiographs were taken and points representing the levels of the inferior dental canal (IDC), root apices (AP), alveolar crest (AC), cementum-enamel junction (CEJ) and occlusal surface were determined on the radiographs. The level of the IDC was used as a reference not changing with age. The distances between the points were measured with a help of a computer-digitizer system. Variable IDC-AP increased with age, indicating continuous eruption of the teeth. The distance between AC and CEJ also increased while the distance between IDC and AC remained constant, showing that the alveolar crest height did not increase accordingly. The lack of inflammatory changes on the alveolar bone surface suggests that occlusal attrition may be compensated for by continuous eruption without bone growth in the alveolar margin.

Significance of some variables on interproximal alveolar bone height based on cross-sectional epidemiologic data.

The objective of the study was to analyze the significance of some variables on interproximal alveolar bone height, based on cross-sectional epidemiologic data from a Swedish survey conducted in 1983-1984, in the northern medical care district of Alvsborg county. 723 dentate individuals (92% of the randomly selected dentate individuals) with complete anamnestic, clinical and radiographic documentation were included in the statistical analyses. The computerized method used to measure interproximal alveolar bone height as a % of root length (B/R) provided data at each measurable interproximal surface of the individual teeth. On the population basis, a multivariate linear regression analysis showed that: (i) mean B/R values did not differ significantly between men and women, (ii) B/R value decreased with increasing age at a linear rate of 0.26% (0.04 mm) per year of age, (iii) the higher the calculus index value, the lower the mean B/R value, (iv) the higher the plaque index value, the higher the mean B/R value, (v) level of education, dentist attendance frequency and prevalence of defective margins of dental restorations did not show any statistically significant association with B/R, (vi) individuals attending the dental hygienist less than once every 2 years had higher mean B/R value than individuals attending the dental hygienist at least once every two years, and (vii) current smokers exhibited significantly lower mean B/R value than former and non-smokers. Individuals smoking more than 5 g of tobacco per day had lower mean B/R values than individuals smoking between 1 and 5 g of tobacco per day. There was no statistically significant relationship between snuffing and B/R.

Marginal alveolar bone height in an adult Swedish population. A radiographic cross-sectional epidemiologic study.

The purpose of the present cross-sectional epidemiologic study was to assess the interproximal alveolar bone level within the dentition of 732 randomly selected adult individuals, stratified according to gender and age. Full mouth series of periapical radiographs were used for the assessments of the relation alveolar bone height/root length (B/R). A computer/digitizer recording method was utilized for the assessments. The results were presented as (i) mean values per age group and gender, (ii) mean frequency of subjects with sites exceeding certain thresholds of bone loss and (iii) cumulative frequencies of subjects with various number and percentual proportion of sites in relation to different B/R-ratio intervals. The results showed a reduction in mean alveolar bone/root ratio with age. The women had a significantly more favourable mean B/R-ratio than men in the ages above 40 years; the women had, however, more missing sites above age 60 years. By older age, there was observed an increased variation between individual mean B/R-ratios. Only a few subjects had a mean B/R-ratio less than or equal to 50%. A subfraction of the subjects in the different age groups had greater than 20% of their sites below a B/R-ratio of 60%. This fraction increased with age.

Prevalence of interproximal periodontal intrabony defects in an adult population in Sweden. A radiographic study.

The aim of this study was to determine the prevalence and localization of interproximal periodontal intrabony defects (IPIDs) in the total adult population of a Swedish county. On each interproximal tooth surface (third molars excluded) in 733 randomly selected dentate individuals aged 20 years and over, one examiner recorded from x5-magnified periapical radiographs, the presence or absence of IPID with a width and depth of at least 5 and 10 mm, respectively, representing 1 and 2 mm unmagnified. Intra-examiner reproducibility determined from double recordings was substantial (kappa = 0.66). Recordings of IPID were compared with those performed by 24 specialist periodontists using their own diagnostic criteria. IPIDs were recorded in 32% of the 733 examined individuals; the number of defects per individual ranged from 1 to 15. The prevalence of IPID increased with increasing age and IPID occurred more frequently in men than in women. IPID was observed more frequently on mesial than on distal tooth surfaces, whereas there was no difference between maxillary and mandibular tooth surfaces. Symmetrical localizations of IPID in relation to the sagittal plane were observed.

Measurement of gingival swelling from dental casts by generation of a moiré pattern with laser light.

The aim of the study was to develop a sensitive measuring method enabling direct evaluation of gingival swelling to be made as registered on dental casts. On two separate occasions, when different degrees of severity of gingival inflammation were present in the same subject, reversible hydrocolloid impressions were taken of the mandible. The casts obtained were located successively in identical three-dimensional relationships in a field of interference fringes generated by two intersecting beams of collimated helium-neon laser light, and were photographed. The evaluation of the moiré pattern obtained directly by superimposition of the two images of the surface studied indicated that a decrease in gingival height of 0.38 mm in the direction of the camera had occurred between the two occasions. The use of a computer-based image-processing system considerably improved the visibility of the pattern. The reproducibility of the impression technique, as well as the relocation and superimposing techniques, proved satisfactory at the moiré resolution used (0.19 mm). The method has potential application in clinical experimental research, and therefore warrants further evaluation.

EPIX: an interactive computer application program for cross-sectional epidemiological, periodontal investigations from X-ray films.

This article introduces the interactive computer application program EPIX and the associated personal computer/digitizer system. The system is used to measure marginal alveolar bone height and to record angular alveolar bone defects, defective margins of dental restorations and dental calculus from 5 X-magnified periapical radiographs in cross-sectional epidemiological investigations. The 134-kBytes compiled BASIC program provides 17 menu options. A complete recording of interproximal tooth surfaces takes on average 20 minutes per subject. Data from 200 subjects can be stored on one 5.25" floppy disk. EPIX transforms data files into text files to enable transfer to main-frame computer for statistical analyses. Data displays on VDU or paper are available. Routines for data location and processing, file processing and visual display of an operator's manual provide additional facilities. EPIX has been used to process an epidemiological material of 912 subjects and has proved to be useful.

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.