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

A Panoramic X-ray as a Supportive Diagnostic Tool for the Screening of Osteoporosis in Patients with Hemophilia A and B

BACKGROUND

Hemophilia is associated with an increased risk of developing osteoporosis and osteopenia. The aim of the study was to interpret the usefulness of fractal analysis of the trabecular bone of the mandible (FD) and selected radiomorphic indices (the antegonial index (AI) and Klemetti index (KI)) to assess the risk of reduced bone mineral density (BMD) in patients with hemophilia A/B.

METHODS

The study group consisted of 50 patients with type A/B hemophilia. The control group consisted of 25 males without congenital bleeding disorders. The patients had a panoramic radiograph taken with the same X-ray machine (Vistapano S, Durr Dental, Bietigheim-Bissingen, Germany). The AudaXCeph software (Audax d.o.o., Ljubljana, Slovenia) was used to evaluate the AI index, and the ImageJ, software with a specially prepared script, was used to evaluate the FD. The mandibular cortex was assessed distal to the mental foramen using the Klemetti index.

RESULTS

There were no statistically significant differences between the AI, KI and FD values between the study group and the control group.

CONCLUSIONS

This study indicated the lack of usefulness of AI, KI and fractal analysis in identifying patients with hemophilia at risk of reduced bone mass.

Composition and Properties of Saliva in Patients with Osteoporosis Taking Antiresorptive Drugs

The aim of this study was to examine how the composition and properties of saliva change in people with osteoporosis who have received antiresorptive (AR) treatment, compared to patients with osteoporosis who have not yet received this treatment.

METHODS

The study population consisted of 38 patients with osteoporosis using AR drugs (Group I) and 16 patients with osteoporosis who had never used AR drugs (Group II). The control group consisted of 32 people without osteoporosis. Laboratory tests included determination of pH and concentrations of Ca, PO₄, total protein, lactoferrin, lysozyme, sIgA, IgA, cortisol, neopterin, activity of amylase at rest, and stimulated saliva. The buffering capacity of stimulated saliva was also determined.

RESULTS

There were no statistically significant differences between the saliva of Group I and Group II. No statistically significant correlation was found between the amount of time using AR therapy (Group I) and the tested parameters of the saliva. Significant differences were found between Group I and the control group. The concentrations of PO₄, lysozyme, and cortisol were higher, while concentrations of Ca ions, sIgA, and neopterin were lower, in comparison to the control group. The significant differences between Group II and the control group were smaller, and they concerned only the concentrations of lysozyme, cortisol, and neopterin.

CONCLUSIONS

The saliva of people with osteoporosis subjected to AR therapy and those not subjected to AR therapy did not show statistically significant differences in terms of the examined parameters of the saliva. However, the saliva of patients with osteoporosis taking and not taking AR drugs was significantly different compared to the saliva of the control group.

Automatic detection of the mental foramen for estimating mandibular cortical width in dental panoramic radiographs: the seventh survey of the Tromsø Study (Tromsø7) in 2015–2016

Objective

To apply deep learning to a data set of dental panoramic radiographs to detect the mental foramen for automatic assessment of the mandibular cortical width.

Methods

Data from the seventh survey of the Tromsø Study (Tromsø7) were used. The data set contained 5197 randomly chosen dental panoramic radiographs. Four pretrained object detectors were tested. We randomly chose 80% of the data for training and 20% for testing. Models were trained using GeForce RTX 2080 Ti with 11 GB GPU memory (NVIDIA Corporation, Santa Clara, CA, USA). Python programming language version 3.7 was used for analysis.

Results

The EfficientDet-D0 model showed the highest average precision of 0.30. When the threshold to regard a prediction as correct (intersection over union) was set to 0.5, the average precision was 0.79. The RetinaNet model achieved the lowest average precision of 0.23, and the precision was 0.64 when the intersection over union was set to 0.5. The procedure to estimate mandibular cortical width showed acceptable results. Of 100 random images, the algorithm produced an output 93 times, 20 of which were not visually satisfactory.

Conclusions

EfficientDet-D0 effectively detected the mental foramen. Methods for estimating bone quality are important in radiology and require further development.

Potential Biochemical Markers and Radiomorphometric Indices as Predictors of Reduced Bone Mass in Patients with Congenital Hemophilia

Background: The study aimed to evaluate radiomorphometric indices derived from panoramic X-rays and selected blood markers of bone turnover and neutrophil extracellular traps, with a view to identifying hemophilic patients at risk of developing osteoporosis. Methods: The study consisted of 50 adult men with hemophilia A and B (mild, moderate, and severe). The control group consisted of 25 healthy adult men. In both groups, blood samples were collected to determine concentrations of citrullinated histone H3 (CH3) and osteocalcin (BGLAP) with ELISA tests, and panoramic X-rays were obtained. Images were imported into AudaXCeph software to calculate two radiomorphometric indices: mental index (MI) and panoramic mandibular index (PMI). Concentrations of BGLAP and CH3 were compared with MI and PMI values in patients with and without hemophilia. Results: There were statistically significant differences in BGLAP, CH3, and PMI between the study and the control group (p < 0.05). Multivariate logistic regression analysis showed a predictive value for PMI, BGLAP, and CH3.The ROC curve with cutoff point (Youden index) at 0.40—PMI was calculated. No correlation was observed for the PMI index in any particular subgroup of patients. No correlation between MI and BGLAP/CH3 was observed. Conclusions: Simultaneous use of PMI value and BGLAP and CH3 levels may allow the identification of patients with hemophilia who requirea detailed diagnosis of osteoporosis with DXA.

Mandibular cortical bone structure as risk indicator in fractured and non-fractured 80-year-old men and women

Objective

To investigate the association between mandibular cortex parameters and fracture in a group of 286 men and women, 79–80 years of age.

Study design

In a cross-sectional study, the mandibular cortex was evaluated with Klemetti’s index for cortical erosion. The cortical thickness was measured with a ruler adjusting for the magnification factor. The odds ratio (OR) for fracture when having a severely eroded cortex or a cortex thickness < 3 mm was calculated.

Results

A normal cortex was found in 65% of men, whereas only 7% had a severely eroded cortex. The OR for severely eroded cortex  as fracture risk predictor was significant (2.32; 95% CI 1.3–4.2), also when the female group was evaluated separately. A significant difference was found between the mean thickness for men (3.96 mm) and women (2.92 mm), respectively. The OR for cortical thickness < 3 mm was significant (2.00; 95% CI 1.1–3.6) in the total group, but not when men and women were evaluated separately.

Conclusions

Among old women, the cortical parameters were significantly associated with prevalent fracture. In old men, other circumstances may be more important.

Diagnostic Validity of Orthopantomogram Compared to Dual Energy X-ray Absorptiometry Scan in Detecting Osteoporosis

Introduction Osteoporosis is one of the most common and rampant metabolic bone disorders among the geriatric, particularly affecting postmenopausal women. Even though resorption tends to occur more rapidly in bones with a higher proportion of trabecular bone (e.g., vertebrae, pelvis, calcaneus), bones with significant cortical bone content also do undergo resorption, for example, mandible. The dental manifestations that may indicate low-bone density include loose teeth, receding gums, and ill-fitting or loose dentures.

Objective To validate the efficacy of orthopantomograms (OPGs) in recognizing bone mineral density (BMD) changes of the mandible using mandibular cortical index (MCI) and substantiate the same with dual energy X-ray absorptiometry (DEXA) scan on femoral neck and spine.

Materials and Methods This cross-sectional study comprised 60 geriatric patients of both genders. All the patients were subjected to panoramic radiographs wherever clinically indicated. The visual analysis was done based on the radiographic appearance of the mandibular cortical border and results were compared with DEXA scan reports, followed by an analysis of three grades of MCI and BMD statistically.

Results In our study, out of 40 patients in C2 and C3 subgroups, 67% and 20% were normal, respectively. The incidence of osteopenia was 33% in the C2 group and 70% in the C3 group, whereas Osteoporosis was present only among 10% of the population in the C3 group. The difference between the groups are statistically significant (p = 0.01). These findings imply that a progressive link exists between BMD and deteriorating cortical morphology.

Conclusion The purpose of this study is that dentists will be able to refer patients to physicians of suspected low BMD, based on incidental findings on panoramic radiographs for further examination. There is a statistically significant correlation present between DEXA and MCI, so the latter can also be used for screening BMD changes.

Clinical guidelines for the application of panoramic radiographs in screening for osteoporosis

Osteoporotic fractures are associated with an increased risk of subsequent fractures, a higher rate of mortality, and incremental medical costs. Incidental findings, which include some measurements related to the mandibular inferior cortex and the alveolar trabecular bone pattern of the mandible determined on panoramic radiographs, are considered to be a useful tool for identifying asymptomatic individuals at risk of having osteoporosis and/or fragility fractures. We undertook a worldwide literature survey and present the following clinical recommendations. Postmenopausal female dental patients with a mandibular inferior cortical width of less than 3 mm on panoramic radiographs may be at risk of having low skeletal bone mineral density (BMD) or osteoporosis, but not fragility fractures. In addition, those with a severely eroded mandibular inferior cortex may have an increased risk of having low skeletal BMD, osteoporosis, and fragility fractures. The alveolar trabecular bone pattern of the mandible might be useful for identifying female dental patients at risk of having fragility fractures, although further investigation is necessary to confirm this possibility. These incidental findings on panoramic radiographs, when used for identifying asymptomatic postmenopausal female patients at risk of having osteoporosis in general dental practice, may be helpful in reducing the incidence of first fractures, with a consequent reduction in the secondary fractures, medical costs, and mortality associated with osteoporotic fragility fractures, without incurring any additional cost.

Osteoporosis risk assessment in primary dental care-The attitudes of Swedish dentists, patients and medical specialists

OBJECTIVE

To explore and identify the attitudes of dentists, patients and medical specialists regarding implementation of osteoporosis risk assessment into Swedish primary dental care.

BACKGROUND

Osteoporosis is a major health problem leading to fragility fractures. As shown in academic-based research, dental radiological examination can be used for osteoporosis risk assessment. A substantial number of patients undergo radiographic examinations in primary dental care each year, but little is known about implementation of osteoporosis risk assessment in this setting.

MATERIALS AND METHODS

A qualitative research approach using focus group discussions and manifest content analysis was applied. Five focus groups with dentists and representatives from patient support groups and a single individual interview with one medical specialist were included in the sample.

RESULTS

From the manifest content analysis, three categories emerged: (a) barriers to change in practice, (b) benefits to change in practice, and (c) needs and requirements prior to change in practice. Most participants felt that there was insufficient knowledge of osteoporosis as well as a heavy existing workload. A concern was expressed about medical practitioners' willingness to take on responsibility for patients referred by dentists. Representatives from patient support groups highlighted a lack of knowledge about osteoporosis among both the general public and the medical professionals. Clear guidelines and improved communication channels between stakeholders would have to be established to ensure a smooth treatment path for patients.

CONCLUSION

Despite interest in osteoporosis risk assessment in primary dental care, there are political, workflow and educational barriers that must be overcome for successful implementation.

Quantitative Ultrasound of the Mandible as a Novel Screening Approach for Osteoporosis

This study used an axial transmission quantitative ultrasound (QUS) device to assess mandibular bone strength. The aim of the study was first to establish the precision and repeatability of the axial transmission QUS measurement for a range of mandibular anatomic sites, and second to investigate the ability of the modality to differentiate between osteoporotic subjects and a control group. Three groups of adult Caucasian women were recruited: (1) healthy premenopausal women (n = 26), (2) healthy postmenopausal women (n = 48), and (3) women with osteoporosis (n = 53). Subjects were excluded from groups 1 and 2 if they had any pre-existing bone conditions. Speed of sound (SOS) measurements were taken from the mandible using an OmniSense multisite QUS device. Group 3 had dual-energy X-ray absorptiometry scans of the lumbar spine and femur. The most suitable site on the mandible was determined by repeat SOS measurements in 10 healthy premenopausal subjects, at 5 different sites. The parasymphysis site had the lowest root mean squared coefficient of variation at 0.74%, and was chosen as the most suitable site for mandibular SOS measurements. Group 1 and group 2 had significantly higher mean SOS measurements than the osteoporotic subjects (group 3), with means of 3683 m/s (210), 3514 m/s (221), and 3312 m/s (264), respectively. A 1-way analysis of variance confirmed a statistically significant difference between mean SOS measurements from the 3 groups (p < 0.0001). Axial transmission QUS of the mandible can differentiate between subjects with osteoporosis and a healthy control group, and shows potential for use as a screening tool for osteoporosis.

Evaluation of clinical and radiographic indices as predictors of osteoporotic fractures: a 10-year longitudinal study

OBJECTIVES

The aim of the study was to evaluate 2 radiographic and 3 clinical indices as predictors of future osteoporotic fractures.

STUDY DESIGN

In a prospective, longitudinal study with a 10-year fracture follow-up, the 2 radiographic indices mandibular cortical erosion (normal, mild/moderate erosion, and severe erosion of the inferior cortex) and cortex thickness were assessed using panoramic radiographs of 411 women, age 62 to 78 years. The clinical indices were the fracture assessment tool FRAX, the osteoporosis index of risk (OSIRIS), and the osteoporosis self-assessment tool (OST).

RESULTS

The relative risks (RRs) for future fracture were significant for FRAX greater than 15%, 4.1 (95% confidence interval [CI] 2.4-7.2), and for severely eroded cortices, 1.7 (95% CI 1.1-2.8). Cortical thickness less than 3 mm, OSIRIS, and OST were not significant fracture predictors (RR 1.1, 1.4, and 1.5, respectively). For the 5 tested fracture predictors, Fisher's exact test gave the following P values for differences between fracture and nonfracture groups: FRAX <.001, cortical erosion 0.023, OST 0.078, OSIRIS 0.206, and cortical thickness 0.678. The area under the curve was 0.69 for FRAX less than 15%, 0.58 for cortical erosion, and 0.52 for cortical thickness. Adding OSIRIS and OST did not change the area under the curve significantly.

CONCLUSIONS

FRAX and severely eroded cortices predicted fracture but cortical thickness, OSIRIS, and OST did not.

IDIOS: An innovative index for evaluating dental imaging-based osteoporosis screening indices

Purpose

The goal of this study was to develop a new index as an objective reference for evaluating current and newly developed indices used for osteoporosis screening based on dental images. Its name; IDIOS, stands for Index of Dental-imaging Indices of Osteoporosis Screening.

Materials and Methods

A comprehensive PubMed search was conducted to retrieve studies on dental imaging-based indices for osteoporosis screening. The results of the eligible studies, along with other relevant criteria, were used to develop IDIOS, which has scores ranging from 0 (0%) to 15 (100%). The indices presented in the studies we included were then evaluated using IDIOS.

Results

The 104 studies that were included utilized 24, 4, and 9 indices derived from panoramic, periapical, and computed tomographic/cone-beam computed tomographic techniques, respectively. The IDIOS scores for these indices ranged from 0 (0%) to 11.75 (78.32%).

Conclusion

IDIOS is a valuable reference index that facilitates the evaluation of other dental imaging-based osteoporosis screening indices. Furthermore, IDIOS can be utilized to evaluate the accuracy of newly developed indices.

Dental panoramic indices and fractal dimension measurements in osteogenesis imperfecta children under pamidronate treatment

OBJECTIVES

To verify radiomorphometric indices and fractal dimension (FD) in dental panoramic radiographs (DPRs) of children with different types of osteogenesis imperfecta (OI) and also to verify the effect of pamidronate (PAM) treatment in such panoramic analyses.

METHODS

In this retrospective study, 197 DPRs of 62 children with OI Types I, III and IV who were in treatment with a comparable dosage of intravenous PAM were selected. The mandibular cortical width (MCW), mandibular cortical index, visual estimation of the cortical width and FD of three standardized trabecular and cortical mandibular regions of interest were obtained from the radiographs. Factorial analysis of variance and Fisher test were used to compare FD and MCW measurements in children with different types of OI for different PAM cycles.

RESULTS

Children with all types of OI have thinner and more porous mandibular cortices at the beginning of treatment. There were significant differences between MCW and FD of the cortical bone, regarding different types of OI and number of PAM cycles (p = 0.037 and p = 0.044, respectively). FD measurements of the trabecular bone were not statistically different among OI types nor were PAM cycles (p > 0.05).

CONCLUSIONS

Children with OI presented cortical bone alterations after PAM treatment. Both MCW and the FD of the cortical bone were higher in children with OI after PAM treatment. It is argued that cortical bone should be considered for analyzing patients with OI, as well as to monitor the progress of PAM treatment.

Detecting low bone mineral density from dental radiographs: a mini-review

Over a number of years researchers have reported associations between osteoporosis or low bone mineral density and signs that can be detected on dental radiographs, particularly in the width of the inferior mandibular cortex and the texture of the trabecular bone. As patients visit the dentist more regularly than they visit their doctor, there is the possibility that such signs could be used as a means of identifying individuals at risk of developing osteoporosis or suffering from consequent fracture. This paper reviews the historical background behind this research and the current status, including recent developments in automation of measurement using computer image analysis.

Y, Rakesh N, Reddy SS, Santana N, Shetty N. Relationship between femur bone mineral density, body mass index and dental panoramic mandibular cortical width in diagnosis of elderly postmenopausal women with osteoporosis

OBJECTIVES

To measure and determine mandibular cortical width (MCW) on the panoramic radiographs, to evaluate the usefulness of the method in identifying postmenopausal women with low femoral bone mineral densities (f- BMD) and to correlate the radiographic findings on panoramic radiographs with the f-BMD assessed by dual X-ray absorptiometry (DXA) to predict the efficacy of the radiographic method in diagnosing osteoporosis.

MATERIALS AND METHODS

One hundred and twenty postmenopausal women (60 normal and 60 osteoporotic) in the age group of 50-75 y with f-BMD assessed by DXA had undergone panoramic radiographic examination. The patients were classified as normal (T-score ≥ -1.0) and osteoporotic (T-score ≤ -2.5). MCW on panoramic radiographs was measured bilaterally at the mental foramen region with a caliper and their mean was used as the exposure measure in the analysis.

RESULTS

Student t-test showed that mean f-BMD, BMI and MCW was found be less in osteoporotic patients as compared to normal group with a statistically significant p-value < 0.001. Pearson correlation coefficient test revealed that MCW correlated positively with f-BMD and showed a significant decrease with age of the patient.

CONCLUSION

Postmenopausal women with low f-BMD had thinner mandibular cortex at the mental foramen region when compared to normal subjects and are more susceptible to femoral neck fractures. Mandibular inferior cortical width at the mental foramen region could be used to identify postmenopausal women with low f- BMD. Hence, dental panoramic radiographs serve as a useful screening tool for early diagnosis of osteoporotic fractures.

Digital panoramic radiographs are useful for diagnosis of osteoporosis in Korean postmenopausal women

OBJECTIVE

The purpose of this study was to determine whether digital panoramic radiographs could be used for the diagnosis of osteoporosis through evaluation of the radiographs based on the correlation with bone mineral density (BMD).

METHODS

One hundred and ninety-four post-menopausal women were selected from participants who had participated in the Dong-gu study. Panoramic radiographic indices measured are mental index (MI), mandibular cortical index (MCI) and simple visual estimation (SVE). BMD at the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry (DXA). The Pearson's correlation test was performed to analyse the correlation between MI and age and BMD at the lumbar spine, femoral neck and total hip. Multiple linear regression analysis was performed to analyse the association of MI, MCI and SVE with BMD after adjusting for age, height and weight. To determine the optimal cut-off point of MI for the diagnosis of osteoporosis, the receiver operating characteristic analysis was performed.

RESULTS

The MI was positively correlated with BMDs: lumbar spine: r = 0.36, femoral neck: r = 0.59 and total hip: r = 0.58 (p < 0.001). As age increased, MI decreased (r = -0.46). BMD at the lumbar spine and total hip were significantly lower in participants with reduction of mandibular width, thinning and resorption of mandibular cortex by the MI, SVE and MCI, respectively. The optimal cut-off value of MI for the diagnosis of spinal osteoporosis was 2.22 mm.

CONCLUSION

Thickness and morphological changes of mandibular inferior cortical bone are associated with BMD, independent of age, height and weight. These results suggest that MI, MCI and SVE may be useful indices for the diagnosis of osteoporosis in a Korean population.

Relation between Spongy Bone Density in the Maxilla and Skeletal Bone Density

BACKGROUND AND PURPOSE

Osteoporosis is a disease affecting more than 300 million people worldwide and is responsible for numerous medical complications. This study aimed to investigate the relation between skeletal and maxillary bone density.

MATERIALS AND METHODS

Seventy-three patients were recruited and divided between group A (osteoporosis), group B (healthy, control), and group C (osteopenia) on the basis of a dual-energy x-ray absorptiomery (DXA) scan. These patients also received a CT scan on which bone density measurements were performed at five sites: maxilla midline, retromolar tuberosities, incisor, premolars, and molar regions.

RESULTS

The bone density was lower in osteoporotic patients compared with the control patients. The bone mineral density (BMD) of the tuberosities showed the strongest correlations with the BMD of the hip and the spine (respectively, r = 0.50 and r = 0.61). The midline region showed moderate correlations with the hip (r = 0.47) and the spine (r = 0.46). For potential implant sites, the correlations with the BMD of the hip and spine were, however, small to insignificant. Based on measurements of bone density of the maxilla, it was possible to predict if the patient was osteoporotic or not with a sensitivity of 65% and a specificity of 83%.

CONCLUSIONS

The maxillary bone density of subjects with osteoporosis is significantly lower than that of healthy patients. Moreover, there is a direct correlation between the density of the skeleton and the density of some sites of the maxilla. Using measurements of maxillary bone density in order to predict skeletal bone density might be a useful tool for the screening of osteoporosis.

Mandibular bone structure, bone mineral density, and clinical variables as fracture predictors: a 15-year follow-up of female patients in a dental clinic

OBJECTIVE

To compare three mandibular trabeculation evaluation methods, clinical variables, and osteoporosis as fracture predictors in women.

STUDY DESIGN

One hundred and thirty-six female dental patients (35-94 years) answered a questionnaire in 1996 and 2011. Using intra-oral radiographs from 1996, five methods were compared as fracture predictors: (1) mandibular bone structure evaluated with a visual radiographic index, (2) bone texture, (3) size and number of intertrabecular spaces calculated with Jaw-X software, (4) fracture probability calculated with a fracture risk assessment tool (FRAX), and (5) osteoporosis diagnosis based on dual-energy-X-ray absorptiometry. Differences were assessed with the Mann-Whitney test and relative risk calculated.

RESULTS

Previous fracture, gluco-corticoid medication, and bone texture were significant indicators of future and total (previous plus future) fracture. Osteoporosis diagnosis, sparse trabeculation, Jaw-X, and FRAX were significant predictors of total but not future fracture.

CONCLUSION

Clinical and oral bone variables may identify individuals at greatest risk of fracture.

Fractal dimension and mandibular cortical width in normal and osteoporotic men and women

OBJECTIVE

To verify whether fractal dimensions (FD) on the mandibular trabecular and cortical bone and mandibular cortical width (MCW) differ between patients with normal bone mineral density (BMD) and osteoporosis.

STUDY DESIGN

In this retrospective study, 133 dental panoramic radiographs from men aged >60 years and postmenopausal women with a bone densitometry report of the lumbar spine and hip classified as either normal or osteoporotic were selected. Fractal dimensions of five standardized trabecular and cortical mandibular regions of interest and mandibular cortical width were measured on the panoramic radiographs by an experienced oral radiologist, blinded to the densitometric diagnosis. The following statistical analyses were performed: ANOVA and a forward logistic stepwise regression to verify associations between dental panoramic measurements and the densitometric diagnosis. P values less than .05 indicated statistical significance.

MAIN OUTCOME MEASURES

Fractal dimension and mandibular cortical width.

RESULTS

Differences were found in the FD values on mandibular cortical bone and MCW between patients with normal BMD and with osteoporosis, but not in the FD values of trabecular bone. The odds of having lower mean values of MCW and FD on cortical bone were 2.16, 3125 and 1005 times in osteoporotic patients, respectively, compared with patients with normal BMD.

CONCLUSION

The values of FD analysis on mandibular cortical bone and MCW were lower in women with osteoporosis. A well-adjusted logistic regression model showed that cortical bone measurements might be considered as auxiliary tools to referring patients for DXA exam.

Mandibular cortical shape index in non-standardised panoramic radiographs for identifying patients with osteoporosis as defined by the German Osteology Organization

The aim of this prospective controlled study was to determine the validity of the mandibular cortical shape index (CI) on panoramic radiographs in distinguishing patients with osteoporosis as defined by the German Osteology Organization (Dachverbands der Deutschsprachigen Osteologischen Fachgesellschaften, DVO). The study group contained 50 patients (33 female, 17 male, mean age: 74.9 years), who had a high risk of osteoporosis. 50 young patients (33 female, 17 male, mean age: 37.9 years) with no anamnestic evidence of osteoporosis served as control. Three blinded observers evaluated panoramic views of the study and the control group in a mixed manner regarding the mandibular cortical shape index. The study group underwent bone mineral density measurement using dual energy X-ray absorptiometry and received a diagnosis according to the Organization's guidelines (normal, osteopenia, osteoporosis). The CI showed a high sensitivity of 72.2% and a high specificity of 93.9% with a highly significant predictive value (Chi-square = 22.96, p < 0.001), while the observer's agreement was moderate (kappa = 0.47). We concluded that patients with a cortical shape index of the category assessed as "severe" on non-standardised panoramic radiographs have a higher risk of suffering systemic osteoporosis. The CI in panoramic radiographs is a good screening tool, which could be implemented in the routine assessment of panoramic radiographs in elder patients.

Increased vertebral morphometric fracture in patients with postsurgical hypoparathyroidism despite normal bone mineral density

BACKGROUND

The mechanism behind parathyroid hormone (PTH) activation of bone remodeling is intimately dependent on the time of exposure of bone cells to hormone levels. Sustained high PTH levels trigger catabolism, while transitory elevations induce anabolism. The effects of hypoparathyroidism (PhPT) on bone are unknown. The objective was to study the impact of PhPT on bone mineral density (BMD), on the frequency of subclinical vertebral fracture and on mandible morphometry.

METHODS

The study comprised thirty-three postmenopausal women, 17 controls (CG) and 16 with PhPT (PhPTG) matched for age, weight and height. Bone mineral density (BMD) of lumbar spine, total hip and 1/3 radius, radiographic evaluation of vertebral morphometry, panoramic radiography of the mandible, and biochemical evaluation of mineral metabolism and bone remodeling were evaluated in both groups.

RESULTS

There were no significant differences in lumbar spine or total hip BMD between groups. There was marked heterogeneity of lumbar spine BMD in PhPTG (high = 4, normal = 9, osteopenia = 1, and osteoporosis = 2 patients). BMD was decreased in the 1/3 radius in PhPTG P < 0.005). The PhPTG group exhibited an increased frequency of morphometric vertebral fractures and decreased mandible cortical thickness.

CONCLUSION

The study suggests that vertebral fragility occurs in PhPT despite normal or even high BMD. The current results encourage further studies to evaluate the use of panoramic radiography in the identification of osteometabolic disorders, such as PhPT and the development of a more physiological treatment for PhPT.

Relationship between bone mineral density and trabecular bone pattern in postmenopausal osteoporotic Brazilian women

OBJECTIVES

The aim of this study is to evaluate the relative efficacy of the mandibular trabecular bone in detecting osteoporotic-associated bone changes in Brazilian women.

MATERIALS AND METHODS

Seventy-three digital panoramic radiographs of healthy and osteoporotic postmenopausal women were used. Regions of interest were selected in the mandibular angle and body of the panoramic images, which were analyzed for fractal dimension (FD) and pixel intensity (PI). Statistical analysis evaluated the distribution pattern, compared normal with osteoporotic patients and the right with the left mandible, and assessed the relationship between FD and PI. The significance level was set at 0.05.

RESULTS

FD and PI values were significantly different (p < 0.05) between normal and osteoporotic patients for the right and left mandibular angle and for the left mandibular body. There was no significant difference (p > 0.05) between the right and left mandibular angle for FD and PI, but a significant difference (p < 0.05) was observed on the mandibular body for PI values. FD and PI values presented positive correlation.

CONCLUSIONS

The mandibular trabecular bone was effective in detecting osteoporotic changes, with the exception of the right mandibular body.

CLINICAL RELEVANCE

Mandibular trabecular bone shows a promising attempt of accurate detection of osteoporotic changes in some regions of the jaws. Fractal analysis and pixel intensity had strong positive correlation.

Object position and image magnification in dental panoramic radiography: a theoretical analysis

OBJECTIVES

The purpose of our study was to investigate how image magnification and distortion in dental panoramic radiography are influenced by object size and position for a small round object such as a ball bearing used for calibration.

METHODS

Two ball bearings (2.5 mm and 6 mm in diameter) were placed at approximately the same position between the teeth of a plastic skull and radiographed 21 times. The skull was replaced each time. Their images were measured by software using edge detection and ellipse-fitting algorithms. Using a standard definition of magnification, equations were derived to enable an object's magnification to be determined from its position and vice versa knowing the diameter and machine parameters.

RESULTS

The average magnification of the 2.5 mm ball bearing was 1.292 (0.0445) horizontally and 1.257 (0.0067) vertically with a mean ratio of 1.028 (0.0322); standard deviations are in parentheses. The figures for the 6 mm ball bearing were 1.286 (0.0068), 1.255 (0.0018) and 1.025 (0.0061), respectively. Derived positions of each ball bearing from magnification were more consistent horizontally than vertically. There was less variation in either direction for the 6 mm ball bearing than the 2.5 mm one.

CONCLUSIONS

Automatic measurement of image size resulted in less variation in vertical magnification values than horizontal. There are only certain positions in the focal trough that achieve zero distortion. Object location can be determined from its diameter, measured magnification and machine parameters. The 6 mm diameter ball bearing is preferable to the 2.5 mm one for more reliable magnification measurement and position determination.

Measurement error in statistical models of shape

Active shape models (ASMs) are popular and sophisticated methods of extracting features in (especially medical) images. Here we analyse the error in placing ASM points on the boundary of the feature. By using replications, a corrected covariance matrix is presented that should reduce the effects of placement error. We show analytically and via simulations that the cumulative variability for a given number of eigenvalues retained in principal components analysis (PCA) ought to be reduced by increasing levels of point-placement error. Results for predicted errors are in excellent agreement with the set-up parameters of two simulated shapes and with anecdotal evidence from the trained experts for real data taken from the OSTEODENT project. We derive an equation for the reliability of placing the points and we find values of 0.79 and 0.85 (where 0=bad and 1=good) for the two clinical experts for the OSTEODENT data. These analyses help us to understand the sources and effects of measurement error in shape models.

Radiological and histologic studies of the mandibular cortex of ovariectomized monkeys

OBJECTIVE

The objective was to study the radiological and histologic changes in the mandibular cortices of ovariectomized monkeys.

STUDY DESIGN

Twelve female, adult, Cynomolgus monkeys (Macaca fascicularis) were used. Under anesthesia, 1 group was bilaterally ovariectomized (OVX), and the other (control group) underwent sham surgery. Seventy-six weeks after surgery, the monkeys were humanely killed, their mandibles were excised, and their mandibular inferior cortices (MIC) and adjacent cortices were examined histologically and with panoramic radiographs and micro computed tomography.

RESULTS

Striped shadows were seen on the endosteal side of the OVX cortices on panoramic radiographs. Histologic observation revealed many enlarged pores with eroded surfaces and calcein labeling (indicating osteon remodeling) in the OVX cortices.

CONCLUSIONS

In the MIC and adjacent cortices of OVX monkeys, enlarged Haversian canals were seen and there were indications of a high rate of bone turnover. The enlarged Haversian canals resulted in striped shadows and unclear endosteal margins on radiographic images.

Changes in mandibular cortical width measurements with age in men and women

Automated software was used to measure the mandibular cortical width in a large sample of dental radiographs. We determined that cortical thinning normally starts in women at age 42.5 years and accelerates thereafter. We can estimate population referral rates and thus enable cost benefit analyses for osteoporosis detection by dentists.

INTRODUCTION

Previous studies have shown that the mandibular cortical width is significantly correlated with the bone mineral density at sites which may undergo osteoporotic fracture, e.g. hip. Mandibular cortical width can be determined automatically from dental panoramic radiographs that dentists frequently request, using appropriate software. We study the distribution of cortical width given age to predict those patients requiring further investigation for osteoporosis.

METHODS

The mandibular cortical width was measured in 4,949 dental panoramic tomograms, in patients aged 15-94 years. The inferior and superior cortical edges were detected automatically using a global active shape model image search, followed by an active appearance model search. Nonparametric statistical analysis and nonlinear piecewise linear/quadratic regression were used to analyse the data.

RESULTS

For females, the mean cortical width had a linear increase before the age of 17 years, a period of no change (estimate = 3.25 mm, se = 0.01) until the age of 42.5 years, followed by a quadratic decrease with age. For males, it had a linear increase before the age of 19 years, a constant value (estimate = 0.37 mm, se = 0.01) until the age of 36 years and then a slow linear decrease. The rate of decrease in mean cortical width goes from 0.049 to 0.105 standard deviations per year in the 60-80-year-old female age group, in line with published bone mineral density T-score reductions.

CONCLUSIONS

The pattern of decrease in mandibular cortical width with age was similar to the known pattern of bone loss from the hip, accelerating in women after the age of 42.5 years.

The facial skeleton in patients with osteoporosis: a field for disease signs and treatment complications

Osteoporosis affects all bones, including those of the facial skeleton. To date the facial bones have not drawn much attention due to the minimal probability of morbid fractures. Hearing and dentition loss due to osteoporosis has been reported. New research findings suggest that radiologic examination of the facial skeleton can be a cost-effective adjunct to complement the early diagnosis and the follow up of osteoporosis patients. Bone-mass preservation treatments have been associated with osteomyelitis of the jawbones, a condition commonly described as osteonecrosis of the jaws (ONJ). The facial skeleton, where alimentary tract mucosa attaches directly to periosteum and teeth which lie in their sockets of alveolar bone, is an area unique for the early detection of osteoporosis but also for the prevention of treatment-associated complications. We review facial bone involvement in patients with osteoporosis and we present data that make the multidisciplinary approach of these patients more appealing for both practitioners and dentists. With regard to ONJ, a tabular summary with currently available evidence is provided to facilitate multidisciplinary practice coordination for the treatment of patients receiving bisphosphonates.

Modern dental imaging: a review of the current technology and clinical applications in dental practice

A review of modern imaging techniques commonly used in dental practice and their clinical applications is presented. The current dental examinations consist of intraoral imaging with digital indirect and direct receptors, while extraoral imaging is divided into traditional tomographic/panoramic imaging and the more recently introduced cone beam computed tomography. Applications, limitations and current trends of these dental "in-office" radiographic techniques are discussed.