An investigation into the accuracy of measurements made on radiographs of the alveolar crests of dried mandibles

The treatment timing of labial inversely impacted maxillary central incisors: A prospective study

OBJECTIVE

To determine the timing of treatment for the labial inversely impacted maxillary central incisors.

METHODS

Twenty-eight patients (mean age, 8.2 years) with labial inversely impacted maxillary central incisors were divided into early-treated and later-treated groups according to their dental age. All of the patients were treated with a combination of surgery and orthodontic traction using the Guide rod appliance. Cone-beam computed tomography images were taken immediately after treatment for assessing the root morphology, root length, and alveolar bone loss. Sagittal slices were evaluated at the widest labial-lingual width of the tooth in the axial view. All variables were evaluated by Simplant 13.0 software (Materialise Dental NV, Leuven, Belgium).

RESULTS

The rank sum test indicated that the root length of two groups showed a statistically significant difference between the impacted and homonym tooth, with a shorter length in the impacted tooth (P < .05). The D-value (difference of root length between the impacted and homonym tooth) and alveolar bone loss on the labial side of the impacted incisor are significantly less in the early-treated groups when compared with the later-treated groups (P < .05). Spearman rank correlation analysis showed a statistically positive association between the treatment timing and D-value (r  =  .623, P < .05). The chi-square test for morphology of root apex indicated that the incidence of the root-apex-directed labial side is significantly higher in the later-treated groups when compared with the early-treated groups.

CONCLUSION

The labial inversely impacted maxillary central incisors should be treated early to promote root development by achieving a better morphology of root apex, thus reducing the risk of alveolar bone loss on the labial side.

Prevalence of Periodontal Bone Loss in Brazilian Adolescents through Interproximal Radiography

Purpose. The aim of this study was to verify the prevalence of alveolar bone loss in Brazilian adolescents through the interproximal X-rays analysis. Methods. Bilateral and standardized interproximal (bitewing) X-rays were performed in 15-year-old adolescents (n = 326), and the processing of films and measurements of alveolar bone levels were accomplished by a single examiner. A distance between the cementoenamel junction (CEJ) and the alveolar bone crest more than 2 mm was considered as periodontal bone loss. Results. The results showed percentage of bone loss of 10.4% with predominance of horizontal defects (8.9%) over the vertical types (1.5%). It was verified higher individual distribution of one lesion (67.6%) than two (26.5%) or three lesions (5.6%), and higher occurrence was detected in men (14.95) than in women (8.21). Conclusion. It can be concluded that the interproximal radiography was an efficient method for the detection of alveolar bone loss, revealing low prevalence in adolescents and predominance of horizontal bone defects.

Alveolar Bone Loss around Incisors in Surgical Skeletal Class III Patients

Objective: To test the hypothesis that there is no difference in the vertical alveolar bone levels and alveolar bone thickness around the maxillary and mandibular central incisors in surgically treated skeletal Class III malocclusion patients.

Materials and Methods: The study sample comprised 20 Korean patients with skeletal Class III malocclusion with anterior crossbite and openbite (9 male, 11 female, mean ages 24.1). Three-dimensional cone beam computed tomography images were taken at least 1 month before the orthognathic surgery, and sagittal slices chosen at the labio-lingually widest point of the maxillary and mandibular right central incisor were evaluated. Measurement of the amount of vertical alveolar bone levels and alveolar bone thickness of the labial and lingual plate at the root apex was made using the SimPlant Pro 12.0 program.

Results: The mandibular incisors showed reduced vertical alveolar bone levels than the maxillary incisors, especially on the lingual side. The alveolar bone thickness was significantly greater on the lingual side in the maxillary incisors, whereas the mandibular incisors exhibited an opposite result (P &lt; .05). The percentage of vertical bone loss to root length showed a statistically significant difference between the upper labial and lower labial alveolar bone and also between the upper lingual and lower lingual alveolar bone, showing more bone loss in the lower incisors (P &lt; .001).

Conclusions: The hypothesis is rejected. For the skeletal Class III patients undergoing orthognathic surgery, special care should be taken to prevent or not aggravate preexisting alveolar bone loss in the anterior teeth, especially in the mandible.

Calculus deposits and bone loss on the teeth of Romano-British and eighteenth-century Londoners

The relation between dental calculus and periodontal disease is not clear but it is generally recognized that calculus is a significant pathogenetic factor. Skeletal material has previously been used to study some aspects of chronic adult periodontitis but few studies have quantified the extent of calculus in ancient populations and its relation to changes in alveolar bone height. This study records the presence and extent of calculus and its relation to alveolar bone loss in a Romano-British and eighteenth-century London population. There were significant differences in calculus deposition in the two populations but this appeared to have little effect on changes in alveolar bone contour. It is suggested that the amount of calculus may be related to diet but that changes in alveolar bone height seem to be independently controlled.

Accuracy of quantitative digital subtraction radiography for determining changes in calcium mass in mandibular bone: an in vitro study

The aim of this in vitro study was to determine the accuracy of digital subtraction radiography (DSR) to detect small changes in calcium mass in alveolar bone adjacent to tooth roots. In each of 4 dried porcine mandible segments, one interproximal and one buccal "defect" region was defined adjacent to a premolar root. A series of cortical and cancellous bone slices with a 50 microns--stepwise increasing thickness (0-5000 microns) were attached to the mandible segments covering the respective "defect" region. Standardized radiographs were quantitatively assessed for density changes using DSR. After dissolving each bone slice in hydrochloric acid, its calcium concentration was photometrically determined. For each bone slice, the mean calcium mass covering a single pixel of the subtraction image was calculated. The Wilcoxon signed-rank test and the Mann-Whitney U-test were used for statistical analysis (alpha = 0.05). A strong linear correlation (r2 = 0.86-1.00; p < or = 0.001) was found between the thickness of the bone slices and their calcium mass. Cortical bone showed a 3.5 times higher mean calcium mass/pixel than cancellous bone. Furthermore, a strong linear correlation (r2 = 0.63-1.00; p < or = 0.001) was found between the mean calcium mass per image pixel and the radiographic density changes. Neither the bone type nor the "defect" localization had a significant influence on radiographic density changes caused by changes in calcium mass. A change in mean calcium mass per image pixel of 0.1-0.15 mg was necessary to be detected by DSR. In conclusion, this study revealed a high accuracy of DSR to detect small changes in calcium mass in alveolar cortical and cancellous bone.

Prevalence and severity of apical root resorption and alveolar bone loss in orthodontically treated adults

This study assessed the frequency of root resorption and alveolar bone loss in 88 adults who had undergone orthodontic treatment. Pretreatment and posttreatment periapical radiographs were used to determine the amount of external apical root resorption and alveolar bone loss of the maxillary and mandibular incisors. Alveolar bone loss in the posterior quadrants was determined from bite-wing radiographs. The number of incisors showing root resorption, including blunting, increased from 15% before treatment to 73% after treatment. The number of incisors having moderate to severe apical root resorption was 2% before treatment and 24.5% after treatment. The number of anterior sites in which loss of alveolar bone height exceeded 2 mm from the cementoenamel junction to the alveolar crest increased from 19% before treatment to 37% after treatment; the number of posterior sites was 7% before treatment and 14% after treatment. Bone LOSS > or = 1.5 mm from the pretreatment to posttreatment stages occurred in 11% of the incisors and 3% of the posterior sites. A marked increase in the prevalence of root resorption and alveolar bone loss occurred over the course of treatment. The prevalence of iatrogenic effects for adults may be higher for incisors than in previously reported adolescent studies. A small subgroup with multiple sites of either root resorption or bone loss account for a disproportionate number of iatrogenic sequelae. However, in general, the iatrogenic experience did not preclude the orthodontic treatment of adults.

Reproducibility of repeat bitewing radiographs determined by measurement of the distance between the amelocemental junction and the alveolar crest: an ex vivo study using human skulls

OBJECTIVE

To assess the reproducibility of repeat bitewing radiographs.

METHODS

Five right and left pairs of posterior bitewing radiographs were taken without the use of beam-aiming or film-holding devices in five dry skulls with complete dentitions. The amelocemental junction (ACJ) and alveolar crest (AC) of every interdental site was traced on projected radiographs and the linear distance between the ACF and AC determined.

RESULTS

There was close concordance between the ability to read the ACJ on the approximal tooth surface and the AC. The overall readability of interdental sites was 71% although sites at the extremities of radiographs were often unreadable. Kappa analysis of the readability of alveolar bone height from repeat radiographs was 0.52. There were significant differences in the reproducibility of ACJ and AC measurements from repeated radiographs (p<0.001). Intra-examiner variability was significantly less (p<0.001) than that due to repeat radiography with no significant differences between sites. The standard deviation for all surfaces from repeat readings of the same radiographs was 0.12 mm compared with 0.51 mm from repeat radiography.

CONCLUSIONS

In this study a freehand technique produced a degree of imprecision in readings of alveolar bone height from successive films of the same site. In clinical terms, a difference of more than 1.4 mm between pairs of serial measurements from the same site would have to occur in order to be certain that the difference was not measurement error but real bone loss.

A cohort study of radiographic alveolar bone loss during adolescence

The aim of the present study was to assess the changes in prevalence of early radiographic alveolar bone loss in a birth cohort (all subjects born 1970) over a period of 8 years as related to sex, ethnic origin, orthodontic treatment and socio-economic status. In 1984, the target population consisted of 2767 subjects. In 1986, 1988 and 1992, sets of bite-wing radiographs were obtained from samples of the same population. Alveolar bone loss was recorded if the distance from the cemento-enamel junction to the alveolar crest exceeded 2 mm measured on posterior bite-wing radiographs. The frequency of subjects with radiographic alveolar bone loss increased significantly with age (p < 0.05). The number of subjects with 3 or more lesions also increased with age. The demographic variables studied did not seem to influence the prevalence of bone loss significantly in the present cohort study.

Digital radiographic image-based bone level measurements: effect of film density

Previous studies have demonstrated that accurate alveolar bone-level measurements can be made using digitally enhanced bitewing radiographs. In this study, we determined the effect of exposure variations on bone-level measurement accuracy using digital radiographic images of dry skulls. 6 direct bone-level measurements on the mandibular 1st molars of dry skulls were established by consensus of 2 expert observers. 13 bitewing radiographs were taken on each side of 11 skulls, using a specially designed positioning device. Exposure settings of 70 kVp, 10 mA, and 24 impulses were empirically chosen as the baseline. Kilovoltage and impulses times were individually varied (50 to 100 kVp in 10 kV increments and 15 to 48 impulses in 6 steps) to ensure a wide range of clinically relevant optical densities on the test images. The radiographs were digitized and alveolar bone level measurements, corresponding to those for skulls, were made on the images by 2 observers. Pearson product-moment coefficients between radiographs and criteria measurements were calculated. It was found that dry skull and digital bitewing radiographic measurements were highly correlated, within the limits of exposure parameter variations tested. Accurate measurements of alveolar bone level are possible from bitewing radiographs taken within a wide range of exposures, when digital image processing techniques are employed.

Overhanging amalgam restorations in young adults attending a periodontal department

An important factor affecting plaque retention is the presence of amalgam restorations which are poorly contoured at the gingival margin. The aim of the study was to investigate the occurrence and effects of overhanging amalgam restorations in young adults. One hundred patients, aged 20-29 years, referred to the Periodontal Department, School of Dentistry, Belfast were investigated. Bitewing radiographs were used to examine the restorative status of the approximal surfaces of premolar and permanent molar teeth, excluding third molars. Fifty-seven per cent of the patients investigated had at least one amalgam overhang and 27 per cent had three or more overhangs visible on the radiographs. One hundred and seventy-eight (25 per cent) of the restored approximal surfaces had detectable amalgam overhangs. The mean bone level-amelocemental junction (ACJ) distance related to the approximal surfaces with overhangs was 1.77 (s.d. 1.0) mm and 37 (32 per cent) of these surfaces had bone levels which were greater than 2 mm from the ACJ. The mean bone level-ACJ distance for the other approximal surfaces of the teeth with overhangs was 1.63 (s.d. 1.2) mm. The mean bone level-ACJ distance for matching control surfaces on contralateral teeth was 1.86 (s.d. 1.2) mm. It was concluded that overhanging amalgam restorations were common in the restorations of young adults (20-29 years old) referred for periodontal treatment but were not associated with increased levels of bone destruction.

Tooth components of mandibular deciduous molars of Homo sapiens sapiens and Homo sapiens neanderthalensis: a radiographic study

Tooth components of deciduous molars were measured from standardized radiographs of Homo sapiens sapiens and Homo sapiens neanderthalensis. Enamel height and width were greater in deciduous teeth of Homo sapiens sapiens than in Homo sapiens neanderthalensis and the differences were statistically significant (p less than 0.01). Dentin height showed no significant differences between the two groups, but enamel to floor of pulp chamber and pulp height and width dimensions were significantly greater in Homo sapiens neanderthalensis. Discriminant analysis carried out between groups, using deciduous tooth components, showed an accuracy of 98-100% for identification of Homo sapiens sapiens and 83-92% for identification of Homo sapiens neanderthalensis. The results obtained in this study on dental dimensions support the hypothesis of a distinct evolutionary line for Neanderthals.

The effect of alignment errors on bitewing-based bone loss measurements

Alveolar bone loss measurements made using digitized dental radiographs have been shown to be precise and accurate. We determined the influence of alignment errors introduced when exposing the radiographs on the precision and accuracy of bone loss measurements. Bitewing radiographs of 15 day skulls were obtained using a positioning device (modified after the methods of Duckworth and associates). The sequence of radiographs was taken while the alignment of the main Roentgen beam was systematically varied within a 10 degree cone. Angular displacements were calculated from the digitized radiographs. Space variant digital image enhancement was performed to improve visualization of the cementoenamel junctions and alveolar crests. Corresponding bone loss measurements were made on dry skulls and radiographs. The criterion for truth in these measurements was established by 2 expert observers who measured the skulls with periodontal probes. Radiographic measurements were statistically compared with the criterion using validity coefficients. We found beam positioning errors of up to 10 degrees do not substantively affect alveolar bone loss measurements of mandibular molars taken from enhanced digital images of bitewing radiographs.

Quantitative evaluation of digital dental radiograph imaging systems

Two digital imaging systems, a video camera and analog-to-digital converter, and a charge-coupled device linear photodiode array slide scanner, were tested for their suitability in quantitative studies of periodontal disease. The information content in the original films was estimated, and digital systems were assessed according to these requirements. Radiometric and geometric performance criteria for the digital systems were estimated from measurements and observations. The scanner-based image acquisition (digitization) system had no detectable noise and had a modulation transfer function curve superior to that of the video-based system. The scanner-based system was equivalent to the video-based system in recording radiographic film densities and had more geometric distortion than the video-based system. The comparison demonstrated the superiority of the charge-coupled device linear array system for the quantification of periodontal disease extent and activity.

Criteria for assessment of interproximal bone loss on bite-wing radiographs in adolescents

The present study was performed to determine radiographically the normal distance between the cemento-enamel junction (CEJ) and the alveolar bone crest (AC) as a background for diagnostic decision on bone loss in adolescents. For this purpose, the normal appearance of the alveolar crest was studied in 30, 18-year-olds reported to have had a clinically healthy gingiva at the age of 16 years. A clinical examination was performed and 4 posterior bite-wing radiographs were taken. Sites with bleeding on probing, loss of probing attachment, defective fillings and calculus were excluded from the analysis. At the remaining 737 sites, the distance CEJ-AC was measured on radiographs. Also, the appearance of the marginal bone (normal, sclerotic, notched and/or irregular image, widening of the periodontal ligament space) was recorded. The mean distances CEJ-AC for the separately-recorded maxillary surfaces amounted to 0.9 or 1.0 mm. In the mandible, the distances amounted to 0.7 or 0.8 mm except for the mesial surface of the mandibular first premolar, where a mean distance of 0.5 mm was noted. At maxillary surfaces, 84-90% of the sites showed a distance of 1 mm or less and 94-100% a distance of 1.5 mm or less. At mandibular surfaces, 93-100% of the sites showed a distance of 1.0 mm or less and 100% a distance of 1.5 mm or less. At 4 sites, located at the mesial surface of the first and second premolars in the maxilla, the CEJ-AC distance was recorded as 2 mm. One site was classified as not having a normal appearance.(ABSTRACT TRUNCATED AT 250 WORDS)

Periodontal health at first permanent molars adjacent to primary molar stainless steel crowns

The present investigation was designed to study the effect of stainless steel crowns (SSC), placed on second primary molars, on the periodontal tissues of neighbouring first permanent molars. 36 children (9-12 years old) with an SSC on a second primary molar on one side of the mouth only, were selected for the study. A clinical and radiographic examination was performed at the mesial surface of the first permanent molar, adjacent to the SSC, and at the corresponding area on the contralateral side of the mouth. The clinical examination included gingival and plaque index scores and probing depth measurements. In the radiographic examination, the marginal bone level was assessed. No statistically significant differences in plaque index scores, gingival index scores and probing pocket depth were noted between the mesial surface of first permanent molars and the contralateral control area. Nor were any significant differences in bone level seen. The present findings suggest that the presence of a well-adapted SSC on a second permanent molar does not affect the periodontal health of the neighbouring first permanent molar.

Assessment of bone loss in periodontitis from panoramic radiographs

Bone loss in chronic periodontitis was assessed from panoramic radiographs by direct measurement from the cemento-enamel junction (CEJ) and by measuring the proportion of the tooth length supported by bone. Mesial and distal bone levels of all available teeth were assessed for 50 patients aged 30-39 years referred for periodontal treatment. 85% and 74% of surfaces were measurable by the proportional and direct techniques, respectively. 27% of surfaces had no bone loss according to the proportional score, whereas 22% had a CEJ to alveolar bone distance of less than 2 mm. In addition, over half the surfaces with a proportional bone loss score of zero had a CEJ to alveolar bone distance of 2 mm or more, and for each proportional bone loss score, there was considerable overlap in the CEJ to alveolar bone distances recorded. The validity of the CEJ to alveolar bone measurements was established by comparison with direct measurements at periodontal surgery. The results support the use of direct measurement from the CEJ to alveolar bone rather than the assessment of the proportion of the tooth length within the bone when investigating bone loss from panoramic radiographs. This population of 30-40-year-old periodontal patients had a mean of 50% of sites with a CEJ to alveolar bone distance of 3 mm or more, and at such sites, there was a mean additional bone loss of 2.1 mm.

Variation in prevalence of radiographic alveolar bone loss in subgroups of 14-year-old schoolchildren in Oslo

The aim of the present study was to assess the prevalence of radiographic alveolar bone loss, as related to selected background variables in 2767 14-year old schoolchildren. Bone loss was recorded when the distance from the cemento-enamel junction to the alveolar crest exceeded 2 mm. The radiographs were magnified approximately 10 times. 3% of the subjects and 18.5% of the sites were excluded because of indistinct radiographic reference points. Radiographic bone loss was found in 4.5% of the subjects. Horizontal lesions were more prevalent than vertical defects. Most subjects with bone loss had 1 (75%) or 2 (22%) lesions. No subject was diagnosed with juvenile periodontitis kind of lesion. The prevalence of bone loss depended on the variables sex, orthodontic treatment and ethnic background.

Detection of three-walled infrabony defects by subtraction radiography

An in vitro investigation was undertaken to establish the sensitivity of subtraction radiography for three-walled infrabony defect detection. After the creation of defects of controlled sizes in the interproximal regions of a dried mandible, subsequent radiographs were taken with the help of an occlusal stent. The radiographs were then digitized, and the images were enhanced by frame summation and averaging to reduce electronic noise. Further standardization was facilitated by the use of a step wedge on each radiograph and a computer program to correct variations in processing and exposure. The results show that defect resolution depended not only on the diameter of the defect but also on the mass of the adjacent bone. The smallest detectable lesion was 0.5 mm in diameter in the interproximal region of the premolars. In addition, a change in depth of 1 mm could be detected at the base of three-walled infrabony defects.

Periodontal disease in adolescents: epidemiologic findings in Navajo Indians

A cross-sectional epidemiologic survey was conducted of 618 Navajo Indians, aged 14-19, resident in a boarding school in New Mexico. Periodontal status was assessed by clinical measurements of attachment level and gingival bleeding, and evidence of alveolar bone loss from standardized bitewing radiographs. Attachment level and gingival bleeding were measured at 24 posterior interproximal sites (six sites in each quadrant): the mesio-buccal aspect of the second molar; the disto-buccal and mesio-buccal aspects of the first molar and second premolar; and the disto-buccal aspect of the first premolar. Alveolar bone level was measured from radiographs at the corresponding approximal surfaces of the same teeth. Attachment loss was considered present when the distance from the CEJ to the base of the pocket was greater than 1 mm; bone loss was considered present when the radiographic distance from the CEJ to the alveolar crest was greater than 2 mm, and gingival bleeding was considered present if bleeding occurred immediately after gentle probing. Attachment loss was evident at one or more sites in 88.7% of the population, 45.9% of the subjects had attachment loss at eight or more sites, and 101 subjects (16.3%) had one or more sites with at least 4.0 mm of attachment loss. Bone loss was present at one or more sites in 89.2% of the population, 28.6% had eight or more affected sites, and 4.7% (29 subjects) had one or more sites with at least 2.0 mm of bone loss. Gingival bleeding was evident at one or more sites in 70.6% of the population, and 19.7% had eight or more affected sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of projection angles upon position of cementoenamel junction on radiographs

The CEJ on radiographs is often used as a reference point in the assessment of alveolar bone loss. The aim of the present study was to test the stability of the radiographic CEJ ("RCEJ") in relation to the alveolar crest under varying angulations of the central X-ray beam. In an experimental model four types of extracted teeth were radiographed at 0 degree and 20 degrees vertical angulation and at 15 horizontal angulations varying from a 17.5 degrees mesial view to a 17.5 degrees distal view. The buccal alveolar bone margin was simulated by a steel needle. RCEJ-"crest" distances were read at a X 10 magnification. Changing the vertical angulation from 0 degree to 20 degrees reduced the RCEJ-"crest" distances for all tooth types (range of average reduction 2.2-4.1 mm). Horizontal angulations without concomitant vertical angulation had a significant effect but were without clinical significance. Horizontal angulations in combination with a 20 degrees vertical angulation had a considerable influence; in a mesial view, mesial RCEJ-"crest" distances decreased and distal ones increased, and vice versa in a distal view. The deviations from the true CEJ-crest distance demonstrated may be of clinical significance, and a critical attitude to alveolar bone loss measures on radiographs using the RCEJ as reference point is recommended.

Usefulness of subtraction radiography in the evaluation of periodontal therapy

Subtraction radiography, a sensitive and accurate technique for identifying alveolar crestal change from standardized pairs of radiographs, is useful in monitoring periodontal therapy. One half of the radiographs were found to be appropriate for subtraction analysis using present technology for taking standardized radiographs. The criterion for usability was identical interpretation of subtraction images made in duplicate from a pair of radiographs. A set of radiographs was analyzed by subtraction radiography as well as by measurement of alveolar bone-crest height. Subtraction radiography was found to be more sensitive in detecting change. Whereas 53% pairs of radiographs showed a change on subtraction radiography, only 14% showed a change in crest height. Comparison of change by subtraction radiography and probing attachment level showed an overall correlation. Since these two measures assess different aspects of the periodontium, perfect correlation was not expected.

Comparison between standardized periapical and bitewing radiographs in assessing alveolar bone loss

Readability and alveolar bone level were compared in 455 sets of standardized radiographs each consisting of four periapical (PA) and two bitewing (BW) films. BW radiographs showed significantly higher proportions of unreadable sites in the canines and the mesial surface of first premolars (P less than 0.0001), while PA radiographs exhibited significantly higher proportions of unreadable sites in the distal surface of second molars (P less than 0.0001). Alveolar bone level was assessable in a total of 10016 sites, and the comparison showed identical readings in 82% of the sites. In the maxilla, a significantly higher proportion of sites exhibited larger bone loss measurements (P less than 0.0001) and more sites with significantly higher mean values (P less than 0.005) in BW than in PA films. Mandibular sites showed the opposite trend. The majority of the sites revealed a Pearson's correlation coefficient (r) ranging between 0.60 and 0.82. No significant difference between mean bone loss measurements in the two types of radiographs for all the sites was found. It was concluded that the two radiographic techniques may be used interchangeably in epidemiologic studies.

Quantitative assessment of tooth wear, alveolar-crest height and continuing eruption in a Romano-British population

Although measurements from cement-enamel junction (CEJ) to alveolar crest (AC) have been used in assessing changes in alveolar-crest height as age or chronic inflammatory periodontal disease (CIPD) progresses, there is evidence from ancient populations that the position of AC remains almost constant throughout life and continuing eruption to compensate for attrition may explain why CEJ-AC measurements increase with age. Measurements of occlusal attrition and relationship of CEJ to AC were made on the cheek teeth of 500 Romano-British skulls by direct measurement or by reference to the fixed line of the inferior alveolar canal (IAC) on radiographs. Direct measurements indicated that there were usually no statistical differences between the vertical amounts of tooth substance lost by attrition and the change in the distance CEJ-AC as age progressed. Measurements on radiographs showed that posterior teeth continued to erupt to compensate for attrition and the AC remained static as age progressed. Bone deposition at the AC was seen in the majority of ground sections. Thus tooth wear appears to be compensated by continuing movement of teeth in an occlusal direction. The position of the AC remained almost constant throughout life; AC bone lost by CIPD seemed to be replaced during continuing tooth eruption.

Periodontal disease and approximal overhangs on amalgam restorations in Norwegian 21-year-olds

The prevalence of periodontal disease and overhanging approximal amalgam restorations in molars and premolars was registered in a clinical and radiographic examination of Norwegian adults (born 1959). A random sample of 250 persons was drawn from the populations of two neighboring towns where the Public Dental Services had operated different preventive programs. Results pertain to approximately 175 subjects whose mean age was 21.5 yr (SD 0.3). Twelve subjects had no gingival bleeding and the mean Gingival Bleeding Index of the group was 30.8 (SD 17.6). No pocket depth exceeded 5 mm. In eight subjects the radiographic distance from the cementoenamel junction to the interproximal alveolar crest was greater than 2 mm at one or more teeth. The mean number of filled approximal surfaces in molars and premolars was 12.8 (SD 6.8). Approximal overhangs were present in 87% of subjects, and at 1/4 of restorations. Ninety-six percent of overhangs were less than 0.5 mm. There was no significant difference between the different subgroups of the sample for any of the variables studied.

The relationship between attachment level loss and alveolar bone loss

Standardized radiographs and repeated periodontal probe measurements were made on 22 untreated subjects with destructive periodontal disease monitored for 1 year. Radiographs of selected sites were taken at 0, 6 and 12 months. Measurements of attachment level were made monthly. Radiographic measurements were made on 7X magnified projected images. Alveolar bone height from the CEJ was computed by multiplying the average length of the root times the measured ratio of CEJ to alveolar bone over CEJ to root tip. Each radiograph was measured twice by 2 investigators. Sites were excluded as having indistinct anatomical landmarks in which the standard deviation of the 4 measurements exceeded 0.16 mm, the measurement error for repeat determination of bone height on high quality radiographic images. A 3 sigma critical value for significant bone loss was selected as 0.48 mm. Changes in attachment level were computed for the intervals preceding and during the 6-12 month radiographic measurement period. Based on these critical values, 6.1% of the 231 radiographed sites showed significant bone loss. Similarly, 5.7% of the 1155 probed sites showed significant attachment loss. However, none of the sites with significant bone loss exhibited significant attachment loss over the same time period. In general, significant attachment loss preceded bone loss by 6 to 8 months. At 4 mm, attachment loss was found to predict subsequent bone loss with a true positive ratio of 60% and a false positive ratio of 5%, indicating a high degree of predictive discrimination. These observations indicate that attachment loss precedes radiographic evidence of crestal alveolar bone loss during periods of periodontal disease activity.

Prevalence of bone loss in a group of Brazilian teenagers assessed on bite-wing radiographs

Bite-wing radiographs were used to assess periodontal disease in 304 Brazilian 15-year-old schoolchildren from a population with a low socioeconomic status. The criterion for destructive periodontitis was a distance from the cementoenamel junction to the alveolar crest greater than 2 mm. 90 subjects were excluded, mainly due to missing first molars. Bone loss was diagnosed in 28% of the subjects. More males than females were affected. 50% of all lesions were observed adjacent to first molars. The juvenile periodontitis type of lesion was found in 8 subjects. It was concluded that in young populations bite-wing X-rays seem to be valuable in screening for individuals with incipient bone loss as well as for identification of subjects with juvenile periodontitis. In community programs regular use of this kind of roentgen examination is therefore recommended.

Periodontal bone loss in 15-year-old Norwegians

The prevalence of marginal bone loss was determined on bite-wing radiographs in 2,409 15-year-old schoolchildren living in the country of Buskerud, Norway. Radiographs were collected from all dentists in the area participating in the Public Dental Service. A distance exceeding 2 mm from the cementoenamel junction to the alveolar crest was recorded as bone loss. Bone loss around one or more teeth was found in 11.3% of the subjects. More males than females were affected, with prevalences of 13.7 and 9.0%, respectively. Most of the lesions were observed adjacent to the maxillary first molars. Overt infrabony pockets were found in only a very few cases (0.5%). A clinical examination of 31 of the subjects could not distinguish those with and those without bone loss. The present study has demonstrated that alveolar bone loss is a common finding in 15-year-old school children. It is concluded that bite-wing roentgenograms may be useful in the detection of early bone lesions in young individuals.

Associations between gingivitis, pocket depths, and radiographic bone loss in interproximal areas in young adults

Fifty-five 15-yr-old Brazilian students were selected on the basis of presence or absence of radiographic bone loss. One hundred and fourteen sites were selected, representing areas with and without bone loss, with varying degrees of inflammation and pocket depths. The association between the parameters were evaluated on a site by site basis. Areas with deep pockets more often showed severe inflammation and bone loss than did areas with shallow pockets. However, deep pockets often occurred where no bone loss could be detected radiographically. In this age group clinical assessments seem to overestimate the prevalence of destructive periodontitis, and should be supplemented with radiographic examination for screening purposes and for identification of risk subjects.

Evaluation of endosseous implant abutments as a base for fixed prosthetic appliances. A preliminary clinical study

In the present 2-year report nineteen Linkow blade implants with a total of twenty-seven perforating posts were assessed. All implants included were considered functionally successful and served as abutments for fixed prosthetic appliances. Periodontal probe and radiographic measurements of bone loss around the perforating implant posts, and registration of plaque and gingival index scores were performed every 6 months. During the first 4-6 weeks after implantation a vertical bone loss approximating an average of 1-2 mm occurred in the neck area of the implants. After this initial resorption, bone loss proceeded at a slower rate. The mean annual crest reduction was approximately 0.1 mm from the first to the fourth examination, as assessed from radiographic measurements. Periodontal probe measurements, showing a mean annual crest reduction of 0.2 mm, usually exhibited higher values than corresponding radiographic measurements at both implants and abutment teeth. At implants there was a significant positive correlation between plaque and gingivitis after 18 and 24 months, but not before that time. No correlation was seen between gingival index scores and the degree of bone resorption.

Method for radiographic assessment of alveolar bone level at endosseous implants and abutment teeth

A radiographic method expressing the alveolar bone level in absolute figures is presented. By means of a calibrated measuring radiographic film fixed to a magnifying viewer, alveolar bone levels were determined directly on intraoral periodic "identical" radiographs. A polyether impression was made for fixation of the filmholder in order to obtain reproducible radiographs. The method was applied to assess changes in the alveolar bone level at endosseous implants and abutment teeth. Radiographs of 23 endosseous implants and 21 abutment teeth from nine patients were examined and measurements of the alveolar bone level were performed. The mean difference between double observations on the same exposure as well as on repeated exposures was about 0.2 mm (s.d. 0.17-0.32 mm). The uncertainty of the present radiographic method was mainly due to the measurement procedure, as the radiographic technique showed a high degree of reproducibility. The method is a simple and reliable technique for longitudinal investigations of changes in the alveolar bone level at endosseous implant and tooth abutments.

A radiographic study of the prevalence of chronic periodontitis in 14-year-old English schoolchildren

The prevalence of chronic periodontitis was investigated in six hundred and two 14-year-old English schoolchildren using a standardised radiographic technique. The interproximal spaces on the mesial and distal aspects of the first molar teeth were examined. Oral cleanliness and gingivitis for the anterior teeth and caries prevalence were also recorded. Radiographic evidence of chronic periodontitis was detected in 51.5% of the children examined. No significant relationship was demonstrated between bone loss associated with the first molars and any of the other parameters measured.