Oral radiographic predictors of osteoporosis

A Radiographic comparison of mandibular bone quality in pre- and post-menopausal women in Indian population

Aim and Objectives:

The main objective of the study is to assess mandibular bone changes in pre and postmenopausal women with chronic generalized periodontitis using different radiomorphometric indices, mandibular cortical index (MCI), mental index (MI), and panoramic mandibular index (PMI) in Indian population.

Materials and Methods:

Panoramic radiographs of 60 patients visiting the Department of Periodontology were taken and divided in two groups - pre and post-menopausal. Detailed medical and menopausal history was recorded for each patient. All the radiographs were assessed for PMI, MI and MCI and presence of periodontitis. The destructive periodontitis was assessed as distance from the cementoenamel junction to the alveolar crest greater than 2mm.

Statistical Analysis:

Student-t test was applied to compare mean values of MI and PMI. Intra and inter group comparison of MCI were made using chi-square test. Correlation of age and MI and PMI was found by Pearson’s correlation coefficient.

Results:

MCI, PMI and MI were related to the menopausal status. Patients with C3 category were seen only in post-menopausal group after 54 years of age. Higher mean values for both MI (p<0.05) and PMI (p<0.05) were observed in pre-menopausal group with statistically significant differences. MI showed negative correlation with age in both the groups; however PMI was positively correlated with age.

Conclusions:

Radiomorphometric indices could be used by general dentists after a little training to detect post-menopausal women at higher risk of osteoporosis.

Development of a prediction tool for low bone mass based on clinical data and periapical radiography

OBJECTIVES

This study aimed to develop and test a tool for low bone mass pre-screening by combining periapical radiographs with clinical risk factors.

METHODS

The study sample consisted of 60 post-menopausal women over 40 years of age who were referred for dental radiographs. These patients also had their bone mineral density measured at the lumbar spine and proximal femur using dual-energy X-ray absorptiometry. Radiographic density measurements and 14 morphological features were obtained from each dental radiograph using digital image processing software. The clinical variables considered were age and bone mass index. Classification and regression tree analysis (CART) was used to test the predictive power of clinical and radiographic risk factors for classifying individuals.

RESULTS

CART indicated that the most important variables for classifying patients were age, number of terminal points/periphery, periphery/trabecular area, radiographic density and bone mass index.

CONCLUSION

A combination of clinical and radiographic factors can be used to identify individuals with low bone mineral density, with higher accuracy than any one of these factors taken individually.

Assessment of trabecular pattern on periapical and panoramic radiographs: a pilot study

OBJECTIVE

This methodological study aimed to determine whether the mandibular trabecular bone assessment from panoramic radiographs, using a visual index, corresponds to the evaluation obtained from periapical radiographs.

MATERIAL AND METHODS

A panoramic radiograph and corresponding periapical radiographs of the region of the lower premolars and molars were collected from each of 32 patients (mean age 18.5 +/- 5.5 years). Two calibrated observers assessed randomly the interdental sites between the first molar and second premolar and between the two premolars on all the radiographs using a visual index. Evaluations were repeated with an interval of 60 days. The results of the repeated evaluations were used to assess intra- and inter-observer agreements, employing Kappa statistics. Spearman's correlation was used to determine the association between assessments of panoramic and periapical radiographs.

RESULTS

In total, 79 interdental sites were evaluated on the panoramic and periapical radiographs. The visual analysis of periapical radiographs revealed intra-observer agreements of 0.88 for observer 1 and 0.93 for observer 2, and an inter-observer agreement of 0.82. The intra-observer agreement for panoramic radiographs was 0.79 and 0.83 for observers 1 and 2, respectively, and the inter-observer agreement was 0.79. A substantial correlation was found between periapical and panoramic radiographs (rho = 0.737, p = 0.001).

CONCLUSIONS

Although panoramic radiographs are less reliable than periapical radiographs, they can be used for assessment of the trabecular bone pattern with the aid of a visual index. Training on the method is recommended to obtain results with a high reproducibility.

Cross-sectional study of vitamin D and calcium supplementation effects on chronic periodontitis

BACKGROUND

A low dietary intake of vitamin D and calcium hastens bone loss and osteoporosis. Because vitamin D metabolites may also alter the inflammatory response and have antimicrobial effects, we studied whether the use of vitamin D and calcium supplements affects periodontal disease status.

METHODS

A cohort of 51 subjects receiving periodontal maintenance therapy was recruited from two dental clinics; 23 were taking vitamin D (>or=400 IU/day) and calcium (>or=1,000 mg/day) supplementation, and 28 were not taking such supplementation. All subjects had at least two interproximal sites with >or=3 mm clinical attachment loss. Daily calcium and vitamin D intake (from food and supplements) were estimated by nutritional analysis. The following clinical parameters of periodontal disease were recorded for the mandibular posterior teeth: gingival index, probing depth, cemento-enamel junction-gingival margin distance (attachment loss), bleeding on probing, and furcation involvement. Posterior photostimulable-phosphor bitewing radiographs were taken to determine cemento-enamel junction-alveolar crest distances (alveolar crest height loss). Data were analyzed with a repeated-measures multivariate analysis of variance.

RESULTS

Compared to subjects who did not take vitamin D and calcium supplementation, supplement takers had shallower probing depths, fewer bleeding sites, lower gingival index values, fewer furcation involvements, less attachment loss, and less alveolar crest height loss. The repeated-measures analysis indicated that collectively these differences were borderline significant (P = 0.08).

CONCLUSIONS

In these subjects receiving periodontal maintenance therapy, there was a trend for better periodontal health with vitamin D and calcium supplementation. More expanded longitudinal studies are required to determine the potential of this relationship.

Osteoporosis and oral bone resorption: a review

This paper is a summary of the published studies on the possible association between osteoporosis and alveolar bone loss. Osteoporosis and low bone mass are considered as a major public health problem. The mandible like other bones of the body has a series of anatomical landmarks that can serve as radiographic indicators. Using these indicators it is possible to evaluate changes in bone with respect to its quantity or quality by different methods of taking images. Higher bone resorption was detected in women with a higher number of pregnancies. Also, the higher educated the patient, the less bone resorption. Women with a background of backaches had more bone resorption to those who did not have this backache background. Finally, it was recognized that it would be possible to clear the quality dimension of the process of mandibular bone resorption. If we can identify the osteoporotic process using a basic panoramic radiography measurement technique, then it is possible to intercept the progress of the disease through early warning and treatment. From the results of this study, it can be concluded the thickness of the mandibular angular cortex can be used as an index for bone resorption. A healthy lifestyle has multiple benefits for the mouth and throughout the body. Dental professionals can play a role in preventing osteoporosis by reinforcing this message.

Bone quality assessment based on cone beam computed tomography imaging

OBJECTIVES

The aim of this in vitro study was to investigate the accuracy of fractal analysis and morphometry for bone quality assessment as measured with dual energy X-ray absorptiometry (DXA).

MATERIAL AND METHODS

Nineteen mandibular bone samples were used for the creation of artificial bone lesions (n=5) or decalcification (n=12) to simulate osteoporosis; two samples were used as controls. Cone beam computed tomography (CBCT) and DXA scans were made before and after processing the samples. The image data obtained from the CBCT scans were used to calculate the mean fractal dimension (FD), bone area and density (morphometric analysis) of the samples. Bone mineral density (BMD) was obtained from the DXA scans and set as a reference value for bone quality. The correlation between BMD and FD and between BMD and morphometric results were calculated.

RESULTS

A significant correlation between FD and BMD (rho=+0.71 to +0.75; P<0.05) was observed. Bone area and BMD of the specimens (rho=+0.69 to +0.85; P<0.05) were also significantly related, in contrast to the density analysis, for which no significant correlation to BMD was found.

CONCLUSIONS

The results of this study suggest that fractal analysis and bone area measurement have potential to evaluate bone quality on CBCT images, while density measurement does not seem to be valid.

Diagnosis of osteoporosis in oral health care

Osteoporosis is characterized by an increased risk of bone fractures, affecting especially the forearm, vertebrae and hip. Women are more commonly affected than men because their peak bone density is usually less than that of men at adulthood and declines at the menopause. Early detection of osteoporosis is advisable to prevent the often devastating consequences of hip fracture later in life, though a mass screening programme is not considered cost-effective. Once osteoporotic individuals are identified, drug treatment can be effective in increasing their bone mineral density and reducing fracture rates. Is it possible for dentists to accurately detect early osteoporotic changes on dental radiographs and the affected individuals to be referred to a medical specialist? If the radiographs were taken for other diagnostic purposes, this would increase the cost effectiveness of this regime.

Detecting reduced bone mineral density from dental radiographs using statistical shape models

We describe a novel method of estimating reduced bone mineral density (BMD) from dental panoramic tomograms (DPTs), which show the entire mandible. Careful expert width measurement of the inferior mandibular cortex has been shown to be predictive of BMD in hip and spine osteopenia and osteoporosis. We have implemented a method of automatic measurement of the width by active shape model search, using as training data 132 DPTs of female subjects whose BMD has been established by dual-energy X-ray absorptiometry. We demonstrate that widths measured after fully automatic search are significantly correlated with BMD, and exhibit less variability than manual measurements made by different experts. The correlation is highest towards the lateral region of the mandible, in a position different from that previously employed for manual width measurement. An receiver-operator characterstic (ROC) analysis for identifying osteopenia (T < -1: BMD more than one standard deviation below that of young healthy females) gives an area under curve (AUC) value of 0.64. Using a minimal interaction to initiate active shape model (ASM) search, the measurement can be made at the optimum region of the mandible, resulting in an AUC value of 0.71. Using an independent test set, AUC for detection of osteoporosis (T < -2.5) is 0.81.

Vitamin and Mineral Supplements

BACKGROUND

Vitamins and minerals are essential for systemic and oral health and the prevention of nutrient deficiencies. The author reviews recommendations for their use, consumer intake patterns and considerations for dental practice.

CONCLUSIONS

Vitamin and mineral supplements are designed to treat and prevent deficiency syndromes and promote health. Consumers frequently misuse them, as they are guided by the belief that these supplements will prevent diseases and cure symptoms. Scientific evidence demonstrates their limited usefulness in systemic disease prevention or treatment. The author reviews demonstrated benefits in select diseases.

CLINICAL IMPLICATIONS

Being familiar with the appropriate uses of vitamin and mineral supplements, as well as nutrient-supplement and drug-supplement interactions, will give dental professionals the knowledge to question and advise patients using evidence-based resources.

Measuring cortical thickness on panoramic radiographs: a validation study of the Mental Index

OBJECTIVES

To validate the Mental Index assessment obtained from panoramic radiographs.

STUDY DESIGN

Ten dried mandibles were selected, and standardized panoramic radiographs were obtained. The specimens were then perpendicularly sectioned at the mental foramen region, and the inferior mandibular cortical thickness was recorded using a digital caliper. Measurements of panoramic radiographs were compared with the dried mandibles. Four observers carried out twice the measurements for the panoramic radiographs. Two observers performed twice the measurements of the dried mandibles. Reliability was assessed by duplicate measurements.

RESULTS

Agreement between the actual mandible measurements and the radiographic assessment was moderate for the noncorrected measurements. Agreement between anatomic and radiographic measurements improved remarkably after standard correction for magnification.

CONCLUSIONS

Bone status reports based on measuring cortical thickness of the lower border of the mandible at the mental foramen based on panoramic radiographs, i.e., Mental Index, are accurate. Compensation for magnification, however, is necessary.

A comparison of bone mineral density in the spine, hip and jaws of edentulous subjects

OBJECTIVES

The aim was to investigate the relationship between bone mineral density (BMD) of the jaws (mandible and maxilla) and other skeletal sites. In addition, the influence of gender, smoking and the number of years without natural teeth were examined.

MATERIALS AND METHODS

18 edentulous patients (9 females, 9 males) with a mean age of 67.1 (sd 12.6) years had DXA scans to assess the BMD of the lumbar spine and hip, together with the ramus, body and symphysis of the mandible and the anterior of the maxilla.

RESULTS

BMD values for the ramus were similar to those for the femur but significantly lower than the lumbar spine. The body and anterior mandible had higher values and the anterior maxilla lower values than both the femur and ramus. The ramus BMD showed moderately strong relationships with the standard measures of BMD in the spine and hip, but the BMD of other areas of the jaws showed no relationship with skeletal sites. The BMD for both the hip and the ramus showed an inverse relationship with increasing age. There was no statistically significant relationship between BMD of hip, spine and jaw and either years edentulous or cigarette years. (207)

CONCLUSIONS

Although the ramus of the mandible may show correlation of BMD with skeletal sites, the areas of the jaws where implants may be placed do not. Therefore BMD of the skeletal sites could not be used to predict BMD of the jaws. The BMD of the jaws as measured by DXA showed no relationship with either years edentulous or cigarette smoking.

Prediction of bone mineral density with dental radiographs

There is consensus to use the bone mineral density (BMD) for the operational definition of the degree of osteoporosis and the risk of osteoporotic fractures. Dual X-ray absorptiometry (DXA) is the common technique to determine BMD. Because of high costs and limited availability of DXA equipment it is worthwhile to look for alternative diagnostic techniques. As part of a larger study, the Osteodent project, we investigated if the trabecular pattern on dental radiographs can be used to predict BMD and to identify the subjects with osteoporosis and increased risk of osteoporotic fractures. In four clinical centers 671 women with an average age of 55 years were recruited. BMD values were measured by DXA equipment at the femoral neck, total hip, and spine. One panoramic and two intraoral radiographs were made. From 525 women a complete set of BMD values and radiographs was obtained. Four regions of interest on the radiographs were selected manually and then processed automatically. On all regions of interest mean and standard deviation of the gray values were measured and several features describing the shape of the binarized trabecular pattern. Multiple regression was used to predict BMD of total hip and spine by means of the radiographic measurements combined with age. It was found that age accounts for 10% of the variation in total hip BMD and 14% of the variation in spinal BMD. When all measurements on the dental radiographs are used the explained variation increases to 22% and 23%. The areas under the ROC curves are comparable to those of commonly used screening instruments for osteoporosis. It is concluded that prediction of DXA measurements of BMD by means of quantitative analysis of the trabecular pattern on dental radiographs is feasible.

Comparative study of axial and femoral bone mineral density and parameters of mandibular bone quality in patients receiving dental implants

INTRODUCTION

In view of the increase in the life expectancy of humans and in edentulism of the population above 50 years of age, in which the prevalence of osteoporosis is also higher, it is fundamental to better understand the effects of systemic bone mass loss on the healing process of dental implants and to determine the quality of the bone that surrounds them. The objective of the present study was to compare systemic osteoporosis (axial and femoral) and parameters of mandibular bone quality, and to evaluate osseointegration in postmenopausal women receiving dental implants.

METHODS

The sample consisted of 39 women aged 48-70 years, 19 with a densitometric diagnosis of osteoporosis in the lumbar spine and femoral neck and 20 controls with a normal densitometric diagnosis. Bone mineral density was measured in the patients and controls by dual-energy X-ray absorptiometry. Eighty-two osseointegrated dental implants were placed in the mandible, 39 of them in the osteoporosis group and 43 in the control group. Mandibular bone quality was evaluated by classifying mandibular inferior cortical and trabecular bone on panoramic radiographs and by histomorphometric analysis of a mandibular bone biopsy. Osseointegration was analyzed after 9 months.

RESULTS

No significant difference was observed between patients with osteoporosis and controls when comparing individuals with a normal cortex and those with a severely or moderately eroded cortex determined on panoramic radiographs, although patients with MEC/SEC had lower femoral neck BMD than those with NC (0.688 +/- 0.17 vs. 0.814+/- 0.144 g/cm2, P<0.012). Histomorphometric analysis also revealed no difference in the parameters of bone formation or resorption between the two groups. Implant failure was observed in only one case.

CONCLUSION

We conclude that there is an association between low femoral neck BMD and poor mandibular bone quality as assessed by panoramic radiography. The loss of one implant (1.2%) is compatible with the literature and cannot be attributed to systemic osteoporosis.

Bone density measurements in intra-oral radiographs

Jaw bone density measurements are applicable in many clinical situations to assess bone tissue. To be able to implement research findings in clinical reality, tools must be simple and low cost. Intra-oral radiographs including a reference material perform well as a densitometric tool. However, the inclusion of a reference material, usually in the form of a metal wedge, is an additional burden for the dentist. The aim of this study was to evaluate whether a reference step wedge is required for accurate densitometric results. Dual energy X-ray absorptiometry measurements and densitometric measurements on intra-oral radiographs using a custom-made software were performed on bone samples from the premolar region of the mandible. Observer agreement of bone density expressed as grey value was high. The correlation between mandibular bone mineral density and the densitometric values on intra-oral radiographs was substantially higher when the aluminium step wedge was included. The Wilcoxon test revealed no significant difference between the density measurements using nine or three steps of the Al reference wedge. Density determination of grey value and mm Aleq thickness value both have good intra- and inter-observer agreement. However, jaw bone densitometry is far more accurate when including a reference wedge.

Accuracy in osteoporosis diagnosis of a combination of mandibular cortical width measurement on dental panoramic radiographs and a clinical risk index (OSIRIS): the OSTEODENT project

Clinical questionnaires and dental radiographic findings have both been suggested as methods of identifying women at risk of having osteoporosis and who might benefit from bone densitometry. The aim of this study was to measure the diagnostic accuracy of a combination of mandibular cortical width (MCW) measured from dental panoramic radiographs (DPRs) and the osteoporosis index of risk (OSIRIS) in the diagnosis of osteoporosis. 653 women (age range 45-70 years, mean age 54.95 years) in four European centres underwent standardised dual X-ray energy absorptiometry (DXA) to provide reference data on osteoporosis status. Each subject was interviewed to derive OSIRIS scores and underwent DPR examination. MCW was measured directly by five observers. Receiver Operating Characteristic (ROC) curve analysis was used to calculate sensitivities and specificities of the clinical and radiographic tests for the diagnosis of osteoporosis. 512 (78.4%) of the study population were classified as having normal BMD and 141 (21.6%) as having osteoporosis. Using ROC analysis, OSIRIS gave a ROC curve area (A(z)) of 0.838, with a sensitivity of 70.9% and a specificity of 79.5% at a diagnostic threshold of <or=+1. MCW on DPRs gave Az values for the five observers ranging from 0.71 to 0.78, providing sensitivities between 41.0% and 59.6% and specificities of between 81.8% and 90.3% at a diagnostic threshold of a 3 mm MCW and sensitivities between 94.2% and 99.3% and specificities of between 9.8% and 23.7% at a diagnostic threshold of a 4.5 mm MCW. Inter-observer repeatability was less than 2.15 mm for 95% of subjects. Combining clinical and radiographic tests had the effect of improving specificity at the expense of a fall in sensitivity. Diagnostic thresholds for MCW and OSIRIS can be chosen to provide the sensitivity and specificity combination that best suits locally determined needs. However, the addition of OSIRIS as a stepwise 'follow-up' test to radiographic assessment of MCW should only be performed if the aim is to have a test for which the highest achievable specificity is desired.

Comparative study of axial and femoral bone mineral density and parameters of mandibular bone quality in patients receiving dental implants

INTRODUCTION

In view of the increase in the life expectancy of humans and in edentulism of the population above 50 years of age, in which the prevalence of osteoporosis is also higher, it is fundamental to better understand the effects of systemic bone mass loss on the healing process of dental implants and to determine the quality of the bone that surrounds them. The objective of the present study was to compare systemic osteoporosis (axial and femoral) and parameters of mandibular bone quality, and to evaluate osseointegration in postmenopausal women receiving dental implants.

METHODS

The sample consisted of 39 women aged 48-70 years, 19 with a densitometric diagnosis of osteoporosis in the lumbar spine and femoral neck and 20 controls with a normal densitometric diagnosis. Bone mineral density was measured in the patients and controls by dual-energy X-ray absorptiometry. Eighty-two osseointegrated dental implants were placed in the mandible, 39 of them in the osteoporosis group and 43 in the control group. Mandibular bone quality was evaluated by classifying mandibular inferior cortical and trabecular bone on panoramic radiographs and by histomorphometric analysis of a mandibular bone biopsy. Osseointegration was analyzed after 9 months.

RESULTS

No significant difference was observed between patients with osteoporosis and controls when comparing individuals with a normal cortex and those with a severely or moderately eroded cortex determined on panoramic radiographs. Histomorphometric analysis also revealed no difference in the parameters of bone formation or resorption between the two groups. Implant failure was observed in only one case.

CONCLUSION

We conclude that there is no association between systemic osteoporosis (axial and femur) and parameters of poor mandibular bone quality. The loss of one implant (1.2%) is compatible with the literature and cannot be attributed to systemic osteoporosis.

Accuracy and precision of a densitometric tool for jaw bone

OBJECTIVES

To develop a digital densitometric tool for jaw bone to analyse intraoral radiographs. To assess precision and accuracy for this tool and determine the minimal detection threshold for density changes.

METHODS

Bone samples deriving from the premolar region of 47 human mandibles were selected for analysis. The samples were obtained from adult cadavers in the department of anatomy (Faculty of Medicine, KULeuven) with ethical approval. Digital radiography was performed on all bone samples. Direct volumetric measurements served as gold standard density values and allowed determination of accuracy. Dual-energy X-ray absorptiometry (DXA) scans were performed on all specimens. For all radiographs, density in mm Al eq was calculated using custom-made software, Osteop. Precision and intraobserver and interobserver reliability of this method were assessed. The bone specimens were progressively decalcified. At standard time intervals the percentage of decalcification was calculated. At each decalcification step, radiographs were taken and analysed.

RESULTS

CV was always lower than 3%, which points to a good precision of the method. Correlation between the density measurements in mm Al eq and the DXA results was 0.9, for the density measurements in mm Al eq and the direct density measurements r was 0.5. The custom-made software was able to detect a change in bone mineralization of 6.6%.

CONCLUSIONS

The present method for bone densitometric analysis offers potentials for clinical evaluation of bone density and minute bone density changes in the jaw bone.

Pixel intensity and fractal analyses: detecting osteoporosis in perimenopausal and postmenopausal women by using digital panoramic images

OBJECTIVE

Pixel intensity values (PI) and fractal dimensions (FD) were compared in selected mandibular regions on digital panoramic images of normal, osteopenic, and osteoporotic perimenopausal and postmenopausal women to evaluate their relative efficacies in detecting osteoporotic-associated bone density changes.

STUDY DESIGN

Standardized mandibular angle, body, and canine/premolar (C/PM) regions on 54 charge-coupled device (CCD) digital panoramic images of normal and potentially osteoporotic postmenopausal women were analyzed for PI and FD. Lumbar spine and femoral neck dual-energy x-ray absorptiometry (DXA) on each patient served as the reference standard examination. Pearson correlation coefficients and analysis of variance (ANOVA) were performed.

RESULTS

There was significant correlation among PI measurements (P < 0.01), and no significant correlation between FD. C/PM had significantly lower PI than control C/PM (P = 0.049).

CONCLUSIONS

Osteoporotic changes in mandibular C/PM cancellous bone were detected in our study population on CCD digital panoramic images by using a robust image analysis paradigm. Future automated application of such image analysis could enable widespread, cost effective screening for osteoporosis in dental settings.

Changes in the radiographic characteristics of the mandibular alveolar process in dentate women with varying bone mineral density: a 5-year prospective study

The association between skeletal bone mineral density (BMD) and mandibular alveolar bone mass has been reported to be rather weak, probably due to local functional factors. Many new investigations are therefore focused on assessing the mandibular bone structure. No long-term structural alterations have been reported in human mandibular bone with the exception of alveolar crest changes related to periodontal disease. The aim of this prospective study was to investigate dentate women to see if possible alterations in the radiographic characteristics of the mandibular alveolar bone are related to changes in BMD. The BMD of 131 women (initial age 22-75 years) was determined in the distal forearm with dual energy X-ray absorptiometry on two occasions separated by an interval of 5 years. Mandibular alveolar bone mass (MABM) was assessed both by the optical density and by the grey-level value on digitized, calibrated, periapical radiographs. The radiographic alveolar bone structure was evaluated with a visual index [Lindh C, Petersson A, Rohlin M. Assessment of the trabecular pattern before endosseous implant treatment: diagnostic outcome of periapical radiography in the mandible. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;82:335-43. ] and digitally by the alveolar bone texture. MABM decreased significantly during the 5-year period. Changes in MABM, evaluated by the mean grey-level value of a bone segment between the premolars, were correlated to changes in skeletal BMD (r = 0.33, P < 0.001). Changes in MABM, evaluated by the optical density, did not correlate to changes in skeletal BMD. The overall trabecular pattern did not change during the study period, but small changes in the bone texture were measured. The changes in the bone texture were correlated with BMD change (r = 0.39, P < 0.001). We conclude that changes in the mandibular alveolar bone do reflect changes in the skeletal BMD, and these may be estimated on periapical radiographs by changes in their grey-level value and their texture.

Mandibular morphological changes in low bone mass edentulous females: evaluation of panoramic radiographs

OBJECTIVE

The objective of this study was to evaluate morphological changes of the mandible in osteopenic and osteoporotic edentulous females.

STUDY DESIGN

Fifty-two female edentulous patients underwent panoramic radiography and dual-energy x-ray absorptiometry of the lumbar spine and femoral neck. Measurements of the gonial angle, antegonial angle, antegonial depth, antegonial index (AI), and mental index (MI) were performed. Patients were classified as normal (T-score > -1.0), osteopenic (T-score of -1.0 to 0 -2.5), or osteoporotic (T-score < -2.5).

RESULTS

The gonial angle did not show differences among the three categories of skeletal bone status (P > .05). The antegonial angle was significantly smaller in individuals with low bone mass (P < .05). The antegonial depth was significantly greater in osteoporotic (P < .05) and osteopenic individuals (P < .05). The AI and MI were significantly smaller in individuals with low bone mass (P < .05); however, after age adjustment there were no differences among the groups (P > .05).

CONCLUSIONS

Edentulous females with low bone mass have a deeper antegonial region. The thickness of the cortical mandibular bone is highly influenced by age.

Significance of osteoporosis in craniomaxillofacial surgery: a review of the literature

Osteoporosis is a common problem in orthopedic surgery. The purpose of this review of the literature was to examine whether osteoporosis is also an important factor in patient treatment in the field of craniomaxillofacial surgery. Emphasis was given to the consequences of osteoporosis for the maxilla and mandible, the influence of osteoporosis on fracture treatment, the use of dental implants, the importance of soft tissues and the effect of osteoporosis therapies. It was found that osteoporosis does affect the bones of the skull. The effect of osteoporosis on treatment, however, is controversial and necessitates better ways of quantifying bone loss. Large inter-individual and site-specific differences in bone density, as well as other effects such as removal of teeth, periodontitis, implant insertion, augmentation procedures and altered loading with dystrophic consequences need to be considered in future studies. Special attention should be given to osteoporosis during fracture treatment.

The differences in panoramic mandibular indices and fractal dimension between patients with and without spinal osteoporosis

OBJECTIVES

The aims of this study were to evaluate the relationship between osteoporosis, oral signs, body mass index and age; and to assess the possibility of using these parameters as an indicator of post-menopausal osteoporosis. The oral signs were panoramic-based mandibular indices, such as cortical width, cortical index, panoramic mandibular index and mandibular crest resorption degree; the number of teeth and fractal dimension analysis.

METHODS

Forty-eight post-menopausal women between the ages of 40 years and 64 years were evaluated. Mandibular indices and the number of mandibular teeth were measured and evaluated from panoramic radiographs and fractal dimension was calculated from the direct digital periapical radiographs of the mandibular premolar-molar region in box-counting method. Weight, height, menopausal status and age of the patients were recorded by questionnaire. Bone mineral densities of the patients were measured with dual energy X-ray absorptiometry.

RESULTS

In this study there were no statistically significant differences between the osteoporotic and non-osteoporotic patients for cortical width, panoramic mandibular index, alveolar crest resorption degree, fractal dimension and the number of mandibular teeth, but there was a difference for cortical index. Binary logistic regression analyses demonstrated that age (P = 0.015) was an important risk factor for osteoporosis.

CONCLUSION

The results of this study demonstrated that osteoporotic patients were more likely to have altered inferior cortex morphology than non-osteoporotic patients and age is an important risk factor for osteoporosis.

Radiomorphometric indices and their relation to gender, age, and dental status

OBJECTIVES

To evaluate the antegonial index (AI) and the mental index (MI) in edentulous and dentate patients, in different age groups and between genders.

STUDY DESIGN

We evaluated 312 panoramic radiographs and grouped them into 4 10-year age groups. Gender, dentition status and age were recorded. The measurements were performed by 2 researchers independently.

RESULTS

The AI and MI were significantly smaller in older females, whereas they were greater for older males (P < 0.01). Edentulous individuals had a lower AI than dentate and partially dentate individuals (P < 0.01).

CONCLUSIONS

There is a continuous remodelling in the mandibular cortex with age and this is influenced by dental status and gender. The difficulty of measuring the AI in a reproducible manner, its interaction with dental status and low correlation with MI in younger patients should discourage its use in detecting patients at risk of osteoporosis.

Clinical and panoramic predictors of femur bone mineral density

Dentists are a potentially valuable resource for initial patient screening for signs of osteoporosis, as individuals with osteoporosis have altered architecture of the inferior border of the mandible as seen on panoramic radiographs. Our aim was to evaluate the efficacy of combining clinical and dental panoramic radiographic risk factors for identifying individuals with low femoral bone mass. Bone mineral density was measured at the femoral neck and classified as normal, osteopenic or osteoporotic using WHO criteria in 227 Japanese postmenopausal women (33-84 years). Panoramic radiographs were made of all subjects. Mandibular cortical shape and width was determined and trabecular features were measured in each ramus. Mean subject age, height, and weight were significantly different in the three bone-density groups (P<0.0001). A classification and regression trees (CART) analysis using just clinical risk factors identified 136 (87%) of the 157 individuals with femoral osteopenia or osteoporosis. Mean mandible cortical width (P<0.0001), cortical index (P<0.0001) and trabecular features (P=0.02) were also significantly different in the three bone density groups. A CART analysis considering only radiographic features found 130 (83%) of the 157 individuals with femoral osteopenia or osteoporosis, although none of the subjects with osteoporosis was correctly identified. A CART analysis using both clinical and radiographic features found that the most useful risk factors were thickness of inferior border of the mandible and age. This algorithm identified 130 (83%) of the 157 individuals with femoral osteopenia or osteoporosis. The results of this study suggest that 1) clinical information is as useful as panoramic radiographic information for identifying subjects having low bone mass, and 2) dentists have sufficient clinical and radiographic information to play a useful role in screening for individuals with osteoporosis.

Maxillary bone mineral density and its relationship to the bone mineral density of the lumbar spine and hip

OBJECTIVE

We sought to measure the bone mineral density (BMD) of various regions in the maxilla before implant treatment and to investigate correlations between these values and the BMDs of the spine and hip.

STUDY DESIGN

Eighteen patients were examined by means of quantitative computed tomography, and the BMD of the maxillary alveolar ridge was calculated. The same patients also underwent dual-energy x-ray absorptiometry of the lumbar spine and the total hip. Analysis of variance was used to compare BMD values between and within individuals. The Pearson correlation coefficient was used to correct for sex and body mass and to calculate the correlation between the BMD of the maxillary alveolar ridge and the BMD of the spine and hip.

RESULTS

The maxillary BMD varied significantly between individuals (P <.001) and within individuals (P <.001). The BMD of the anterior region of the maxilla was correlated significantly with the BMD of the lumbar spine (r=0.6; P <.05).

CONCLUSION

A site-specific evaluation of maxillary bone tissue could be of value before implant treatment.

Fourier and wavelet analyses of dental radiographs detect trabecular changes in osteoporosis

OBJECTIVES

Osteoporosis results in loss of bone mass and microarchitectural deterioration. Dental radiographs potentially offer a means of screening for osteoporosis as they are commonly made on adults. Spatial frequency analyses are well suited to detect subtle changes in image patterns. We hypothesize that individuals with osteoporosis exhibit an altered radiographic trabecular pattern that can be detected by spatial frequency and strut analysis.

STUDY DESIGN

Maxillary and mandibular periapical radiographs of 26 women with osteoporosis and 23 controls were examined using one-dimensional discrete Fourier and wavelet analyses in both jaws to measure the spatial frequency distributions of trabecular structures. A strut analysis was also performed.

RESULTS

Individuals with osteoporosis revealed an altered trabecular pattern compared to controls. Using Fourier and strut variables allows classification of subjects with 92% sensitivity, 96% specificity, and a 22% cross-validation error rate. Wavelet analysis was also useful but did not perform better than Fourier analysis for subject classification.

CONCLUSIONS

Spatial frequency analysis of digitized dental radiographs, especially Fourier analysis, and strut analysis provide value for identifying individuals with osteoporosis.

Estrogen and/or Calcium Plus Vitamin D Increase Mandibular Bone Mass

BACKGROUND

We have previously reported that estrogen/hormone replacement therapy (E/HRT) has beneficial effects on oral bone density over 3 years and that calcium and vitamin D supplementation has a lesser effect. Here we report on mandibular bone mass for 49 women (of the original cohort of 135) who continued in an additional 2-year, open-label extension.

METHODS

Postmenopausal women were randomly assigned to receive calcium and vitamin D plus E/HRT, or calcium and vitamin D only. Regression analysis of mandibular bone mass over time was performed for each woman.

RESULTS

Twenty-two of 26 women who took calcium and vitamin D plus E/HRT for 5 years had small mandibular bone mass increases (0.35 +/- 0.38%, P<0.001). Seventeen of 19 women who took only calcium and vitamin D for 3 years had increases in mandibular bone mass (0.74 +/- 0.89%, P<0.002). The largest gains in mandibular bone mass occurred during the first 3 years of the study.

CONCLUSIONS

The data of this study indicate that E/HRT and/or calcium and vitamin D may result in increases of mandibular bone mass in postmenopausal women. Because of the long-term risks associated with E/HRT, caution should be exercised in prescribing E/HRT for prevention of chronic menopausal conditions.

Effects of oestrogen deficiency on rat mandibular and tibial microarchitecture

OBJECTIVES

To investigate the effects of oestrogen deficiency on the microarchitecture of trabecular bone in the mandible and the tibia and to test whether they are correlated.

METHODS

Twenty-four age-matched Lewis-Brown-Norway female rats underwent surgical intervention either to remove ovaries (ovariectomy, n=12) or to create a complementary control group (sham-operated, n=12). Sixteen weeks later, the animals were sacrificed and the left side of the mandibles and the tibias were scanned with high resolution micro-CT (15 micro m). Multiple morphological measures including the ratio of bone volume/tissue volume, trabecular thickness, trabecular separation and structure model index were obtained from the experimental and control groups.

RESULTS

Ovariectomy significantly decreased the ratio of bone volume/soft tissue volume and trabecular thickness, whilst significantly increasing trabecular separation and structure model index in the mandible (P<0.005) and the tibia (P<0.005). There were significant positive correlations between the mandible and the tibia for trabecular separation (r=0.68, P<0.01) and structure model index (r=0.60, P<0.01).

CONCLUSIONS

Oestrogen deficiency results in microarchitectural alterations of trabecular bone in both the mandible and the tibia within 16 weeks. The size of marrow spaces and the shape of trabeculae in the mandible correlate with osteoporotic changes in the long bone.

Visibility of trabecular structures in oral radiographs

OBJECTIVES

To determine whether alveolar trabecular bone is visible and quantifiable in projection radiographs. Radiographic changes in oral trabecular bone have been studied as possible indications of bone loss, but in some previous studies, observed structures have been attributed entirely to the endosteal surface.

METHODS

Computed radiography (CR) images of human mandibles in molar and pre-molar regions were compared with simulations calculated from high-resolution computed-tomography (CT) and micro-CT volumes. By digitally editing the CT volumes, the simulations were separated into trabecular and cortical components. High-pass-filtered CR images revealed structural details of cortical and trabecular bone.

RESULTS

Trabecular bone constitutes as much as 38% of the total alveolar bone, and accounts for most of the observed alveolar fine structure. Several morphological types of fine structure can be distinguished. The noise in filtered images appears to be a meaningful measure of trabecular bone.

CONCLUSION

Trabecular bone is highly visible in intraoral radiographs.