K Nicopoulou-Karayianni

Tooth loss and osteoporosis: the OSTEODENT Study

AIM To determine the cross-sectional association of the osteoporotic status of patients with the number of their teeth, with and without taking into account age and/or smoking. MATERIAL & METHODS At four centres, the study recruited 665 females aged 45-70 years and the number of teeth was counted for 651 subjects. Bone density was measured at the total hip, femoral neck and lumbar spine. RESULTS The mean number of teeth in the osteoporotic subjects was 3.3 fewer than normal subjects and 2.1 fewer if those with no teeth were excluded. The association between osteoporosis and having <6 or having <28 teeth remained significant after adjusting for age, smoking and centre with p-values of 0.016 and 0.011, respectively. A single regression model for tooth count with normal errors would not fit all the data. By fitting mixture regression models to subjects with tooth count >0, three clusters were identified corresponding to different degrees of tooth loss. The overall effect of osteoporosis was as follows: -1.8 teeth before and after adjusting for smoking, -1.2 teeth after adjusting for age, and -1.1 teeth after adjusting for both age and smoking. CONCLUSIONS We have established a significant association between osteoporosis and tooth loss after adjusting the effect for age and smoking.

The relationship between osteoporosis and periodontitis in women aged 45–70 years

OBJECTIVE To explore the possible relationship between the osteoporotic condition and the severity of periodontitis in women aged 45-70 years. MATERIALS AND METHODS Ninety women with generalized chronic periodontitis, aged 45-70 years, were studied. Areal bone mineral density (BMDa) was assessed using standardized dual energy X-ray absorptiometry (normal: T-score ≥ -1, osteopenic: -2.5 ≤ T-score <-1, osteoporotic: T-score < -2.5). Gingival index (GI), bleeding on probing, clinical attachment loss (CAL), probing pocket depth and gingival recession (GR) were recorded. Periodontitis severity was represented by CAL. Menopausal condition and smoking were documented. RESULTS Mean GI, bleeding on probing, CAL and GR were significantly greater for osteoporotic women than women with normal BMDa (P = 0.002, P = 0.01, P = 0.04, respectively). Osteopenic women and women with normal BMDa significantly differed in mean GI (P = 0.02). The associations found between osteoporotic women and women with normal BMDa and the associations found between osteopenic women and women with normal BMDa existed even after adjusting for smoking and menopausal status. CONCLUSION Subjects with osteoporosis (OPR) presented with greater CAL than the subjects with normal BMDa, which suggests a greater severity of periodontitis. Subjects with OPR had greater GR than the subjects with normal BMDa. Subjects with osteopenia and subjects with normal BMDa did not differ in CAL, which might suggest that the early diagnosis of reduced BMDa, prior to the establishment of a significant negative impact on the periodontal tissues, might be important. Smoking and menopausal status did not alter these associations.

The role of the dental surgeon in detecting osteoporosis: the OSTEODENT study

Objective To determine if thinning (<3 mm width) of the lower cortical border of the mandible on dental panoramic radiographs, as well as other clinical risk factors, may provide a useful diagnostic test for osteoporosis in young postmenopausal women.Design Six hundred and fifty-two subjects (age range 45-70 years) were involved in this multi-centre, cross-sectional study.Setting Patients were recruited from centres in Leuven (Belgium), Athens (Greece), Manchester (UK), and Malmo (Sweden).Subjects and methods The subjects age, body weight, whether the patient took hormone replacement therapy or had a history of low trauma fracture were used to form a clinical osteoporosis risk assessment (the OSteoporosis Index of RISk or OSIRIS index). Each patient also received a dental panoramic radiographic examination.Results One hundred and forty subjects had osteoporosis involving at least one of the measurement sites (lumbar spine, femoral neck or total hip). Those with osteoporosis tended to have a low OSIRIS score and a thinned cortical mandibular border. The area under the ROC curve for using both cortical width and OSIRIS to predict osteoporosis was 0.90 (95% CI = 0.87 to 0.92). There was a significant improvement in the diagnostic ability of the combined OSIRIS and cortical width test over both tests applied separately (p <0.001). The cost effectiveness of the cortical width and OSIRIS model was improved by using a high specificity threshold rather than high sensitivity. However, this analysis ignores the costs associated with missed cases of osteoporosis.Conclusion Dentists have a role to play in the detection and referral of patients at high risk of osteoporosis.

Prediction of osteoporosis with dental radiographs and age

OBJECTIVES In this study age and the trabecular pattern present on dental radiographs were used to predict the presence of osteoporosis. The objective was to evaluate the contribution of the trabecular pattern to the prediction. METHODS In this project, 671 women between 45 and 71 years of age were recruited. Medical history was obtained and dental radiographs were made. Bone mineral density (BMD) was measured at three sites to assess the presence of osteoporosis according to the World Health Organization criteria. The radiographs were subjected to image analysis methods yielding measurements of the trabecular pattern. Thereafter, discriminant analysis was used to predict the presence of osteoporosis by means of the trabecular pattern and age. Sensitivity and specificity of age and the trabecular pattern were compared. Also, it was checked whether the inclusion of the trabecular pattern improved the sensitivity and specificity that were obtained when only age was used as the predictor. RESULTS The sensitivity and specificity of the trabecular pattern present on dental radiographs were almost equal to those of age. However, combining age with the trabecular pattern increased the sensitivity from 0.71 to 0.75 and the specificity from 0.72 to 0.78; the latter increase was statistically significant. CONCLUSIONS The trabecular pattern predicts the presence of osteoporosis just as well as age does. When combining the trabecular pattern with age, the sensitivity and specificity increased. Only the latter increase was statistically significant.

Selecting regions of interest on intraoral radiographs for the prediction of bone mineral density

OBJECTIVES A previous study showed that the trabecular pattern on dental radiographs correlates with femoral and spinal bone mineral density (BMD). The objective of this study was to determine if the correlation is affected by the size and location of the region of interest (ROI). METHODS In a European research project on osteoporosis, BMD was measured at the left hip and the lumbar spine of 525 women. From all subjects, intraoral radiographs were made of the premolar region in the upper and lower jaws. Two ROIs were indicated manually on each scanned image. The smallest region involved only trabecular bone and the largest also included parts of the neighbouring teeth. The ROIs were subjected to automatic image analysis, yielding 26 measurements per ROI. Stepwise linear regression was used to predict femoral and spinal BMD. RESULTS Inner and outer regions predicted BMD equally well. The radiographs of lower and upper jaw also predicted BMD equally well. Combining inner and outer regions did not improve the prediction of femoral and spinal BMD, but combining lower and upper jaws did. CONCLUSIONS This study shows that it is possible to include parts of neighbouring teeth in the ROI used to assess the trabecular pattern and predict BMD. This simplifies the process of selecting the ROIs because no efforts have to be made to exclude neighbouring teeth. Combining ROIs of lower and upper jaws significantly improves the prediction of BMD.

The use of digital subtraction radiography to evaluate bone healing after surgical removal of radicular cysts

ObjectiveThe purpose of this study was to evaluate the bone healing process after surgical removal of radicular cysts by using preoperative and postoperative panoramic radiographs, which were digitized and subtracted using a projective standardization software program (Emago).MethodsSeventeen patients with large radicular cysts treated by surgical enucleation were included in the study. All surgical procedures were performed by one of the authors (D.K.). Each patient had a panoramic preoperative radiograph (plain film) and a panoramic postoperative radiograph (plain film), which was taken 6 to 12 months after surgery. All radiographs were taken with the same panoramic unit. The part of the radiograph that included the lesion in the preoperative radiograph was digitized using a CCD digital camera at a standard distance. The postoperative radiograph was also digitized using the same standardized parameters. The preoperative and postoperative images were then manipulated by means of the projective standardization software program Emago to reveal the regenerated area. This area was calculated in pixels, and the percentage of bone healing was determined for each patient. The data were analyzed using Students t test and the Wilcoxon test for pair differences.ResultsThe percentage of bone healing ranged from 55.14% to 95.68% with a mean of 72.27%. In all cases, the differences were significantly different at P = 0.01.ConclusionsDigitizing the part of the panoramic radiograph that included the lesion area and subsequently performing projective standardization is a suitable method for analyzing the healing process by means of subtraction radiography. The projective standardization software program performs the geometric reconstruction and subtraction process. An evaluation of the healing process can be obtained by calculating the regenerated bone area in the subtracted images.

Sex determination by tooth size in a sample of Greek population

Sex assessment from tooth measurements can be of major importance for forensic and bioarchaeological investigations, especially when only teeth or jaws are available. The purpose of this study is to assess the reliability and applicability of establishing sex identity in a sample of Greek population using the discriminant function proposed by Rösing et al. (1995). The study comprised of 172 dental casts derived from two private orthodontic clinics in Athens. The individuals were randomly selected and all had clear medical history. The mesiodistal crown diameters of all the teeth were measured apart from those of the 3rd molars. The values quoted for the sample to which the discriminant function was first applied were similar to those obtained for the Greek sample. The results of the preliminary statistical analysis did not support the use of the specific discriminant function for a reliable determination of sex by means of the mesiodistal diameter of the teeth. However, there was considerable variation between different populations and this might explain the reason for lack of discriminating power of the specific function in the Greek population. In order to investigate whether a better discriminant function could be obtained using the Greek data, separate discriminant function analysis was performed on the same teeth and a different equation emerged without, however, any real improvement in the classification process, with an overall correct classification of 72%. The results showed that there were a considerably higher percentage of females correctly classified than males. The results lead to the conclusion that the use of the mesiodistal diameter of teeth is not as a reliable method as one would have expected for determining sex of human remains from a forensic context. Therefore, this method could be used only in combination with other identification approaches.