Mandibular Cortex Research Articles

A Comparison of Facial and Lingual Cortical Thicknesses in Edentulous Maxillary and Mandibular Sites Measured on Computerized Tomograms

Edentulous ridges suitable for implant treatment depend on cortical bone for implant stability, especially for ridge-expansion procedures. This study was done to find and compare the actual thicknesses of the facial and lingual edentulous cortices of the maxilla and mandible as measured on computerized tomograms. The collected computerized tomographs (CT) of one implantologist's practice (D.F.) were measured. The measurements taken demonstrated that the edentulous lingual cortex is almost always thicker than the facial cortex in the maxilla and mandible. The combined maxillary and mandibular facial cortices measurement sites average was 1.79 mm. The combined maxillary and mandibular lingual cortices measurement sites average was 2.33 mm. The average cortical thickness measurement of the maxillary facial cortices was 1.66 mm. The lingual maxillary average was 2.16 mm. The mandibular facial cortical sites averaged 1.83 mm, while the lingual cortical sites were 2.40 mm. These data confirm that the lingual cortex of the maxilla and mandible is thicker than the facial cortex at a ratio of 1:1.3. This ratio was consistent for maxilla and mandible.

An unnamed branch of the lingual nerve: Gingival branch

Our main aim was to study the mylohyoid nerve, but during cadaveric dissections an unnamed branch of the lingual nerve was encountered incidentally. Dissections of sublingual and pterygomandibular spaces on 13 cadavers preserved in formalin showed an unnamed branch present bilaterally in 11 specimens, which had not been identified before in any of the anatomical textbooks. The branch extended horizontally from the medial mandibular cortex at the level of the retromolar pad to mesial of the lower first molars-second premolars. It was supplying the lingual periosteum, gingiva, and mucosa that were overlying the medial alveolar process. The mean (SD) diameter of the left and right branches was 0.66 (0.1) mm at the branching side. The mean (SD) length of the right and left sides was 28.7 (4.4) mm. The mean (SD) distance from the alveolar crest was 5.8 (0. 9) mm. The lingual nerve supplies the lingual soft tissues; however, none of the anatomical textbooks mention such a subdivision or a branch supplying that part of the oral cavity. We describe the site and the morphological characteristics of this unnamed branch, and recommend that it be named “the gingival branch of the lingual nerve”.

P.204 Myositis ossiflcans traumatica of the bilateral pterygoid

Disorders due to widespread death of bone matrix, osteonecrosis, and focal or systemic bone thickening are reviewed here. Osteonecrosis is a common problem and may be caused by trauma, with direct damage to blood vessels supporting bone or due to fractures that interrupt vascular supply. Osteonecrosis is also caused by metabolic imbalance, commonly due to glucocorticoid administration with secondary ACTH suppression, receptors for both of which are important in bone. Osteonecrosis also occurs with bone-binding antimetabolites, and bisphosphonate osteonecrosis, particularly of the jaw, is an important problem where type and length of treatment affect likelihood of the complication. Sclerotic disorders generally reflect local or systemic changes in bone morphogenetic protein signaling or other signals including sclerostin. Benign focal ossification and several rare diseases reflect this imbalance, including fibrodysplasia ossificans progressiva (FOP), sclerosteosis, osteopoikilosis, and melorheostosis.1. Focal osteonecrosis occurs as a consequence of metabolic or traumatic events. Trauma that interrupts the blood supply to a bone, such as the femoral head, causes osteonecrosis. Regions with abundant trabecular bone are subject to osteonecrosis with disruption of microvascular support by high glucocorticoids especially when ACTH is depressed. Joint replacement is often required. Regions of bone that normally have low turnover, such as the femoral or mandibular cortex, are subject to necrosis in bisphosphonate toxicity. Conditions that increase the likelihood of osteonecrosis should be avoided.2. Myositis ossificans circumscripta, or traumatica, and other heterotopic ossification events are manifest as focal calcification, often with differentiation of true bone, usually at sites of injury. Usually no management is required, although surgical excision may be useful. Localized TGF-β and activin activity has been noted during the development of these lesions.3. FOP is a rare, aggressive disease where many tissues calcify progressively. Most, if not all, of the cases have a constitutively active BMP type I receptor subunit, the activin-like kinase 2. Management is very difficult; attempts to reverse activin signaling are in development.4. Rare diseases with focal cortical thickening may be systemic or local. The syndromes need to be identified as nonmalignant, but specific therapy is not available; symptomatic treatment may be required. Systemic forms include osteosclerosis due to sclerostin defects with diffuse cortical thickening. Osteopoikilosis, characterized by scattered foci of thick bone, is usually associated with dominant mutations in the LEMD3 gene, which regulates BMP signaling. Melorheostosis is an acquired disorder with focal or segmental thickening of the bone cortex likened to dripping candle wax without a known mechanism. It usually involves a segmental region of the skeleton or one bone and may cause deformity and local functional defects in mobility or circulation.

Assessment of panoramic radiomorphometric indices in Turkish patients of different age groups, gender and dental status

The aim of the study was to determine the distribution of the appearance of the inferior mandibular cortex (Mandibular Cortical Index (MCI)) in a large Turkish population group and to assess a range of values for cortical width at the mental foramen region (Mental Index (MI)) and the ratio of the thickness of the mandibular cortex to the distance between the inferior margin of the mental foramen and the inferior mandibular cortex (Panoramic Mandibular Index (PMI)) according to the MCI. In addition, we assess how age, sex and dental status affected the MCI. Panoramic radiographs of 1,863 patients, 698 (37.5%) men and 1,165 (62.5%) women over 20 years old, were assessed during 2005-2006 from the files of Baskent University. Gender, age and dental status were recorded for each patient. MCI classifications, MI and PMI values in the MCI groups were evaluated and comparisons were made using logistic regression analysis. Compared with patients aged 20-49 years, the likelihood of MCI C3 category in patients over 70 years of age and in patients aged 50-69 years of age was 79.14 and 9.17 times higher. The likelihood of the C3 category in edentulous and partially dentate patients was 27.30 and 2.68 times higher than in fully dentate patients, respectively. The likelihood of C3 category in patients with MI <3 mm was 14.86 times higher than in patients with MI >or=3 mm; also, in patients with a PMI of <0.30 this likelihood was 9.78 times higher than in patients with a PMI of >or=0.30. Without respect to gender, edentulous patients with C3 category, MI <3 mm and PMI <0.30 may be seen as high-risk patients for osteoporosis and therefore should be referred for further osteoporosis investigation.

Assessment of the relationship between the mandibular cortex on panoramic radiographs and the risk of bone fracture and vascular disease in 80-year-olds

The objective of this study was to assess cortical measurements on panoramic radiographs in 80-year-old subjects to predict bone fracture and vascular disease risks. The cortical width and shape (normal cortex, mildly to moderately eroded cortex, and severely eroded cortex) were evaluated on 659 panoramic radiographs obtained from 262 men and 397 women, all of whom were 80 years old. At baseline, a general medical examination, including heel bone density, was performed in all subjects. Fractures and vascular disease occurring within 5 years after the baseline examination were determined in 191 subjects and in 108 subjects who died within 5 years after the baseline examination. There were significant correlations between heel bone density and cortical width (r = 0.435, P < .001) and shape (r = 0.231, P < .001). However, cortical measurements on panoramic radiographs were not significantly associated with the occurrence of fractures and vascular disease within 5 years after the baseline examination. Among the elderly, cortical measurements on panoramic radiographs may be associated with bone mineral density and physical activity, but they are not useful markers for the subsequent occurrence of fractures and vascular disease.

Relationship between BMD, dental panoramic radiographic findings and biochemical markers of bone turnover in diagnosis of osteoporosis

Objective Mandibular indices, measured on panoramic radiographs, may be useful screening implements for low skeletal bone mass density (BMD). Recent studies suggest that radiographic examination of mandible may constitute an effective process for the early diagnosis of osteoporosis. Biochemical markers of bone turnover may be of value for prediction of individual bone loss and they may help in predicting risk of fracture in elderly women. In contrast to the vast information available on dental radiographic findings and BMD only scarce data exist on the relationship between panoramic mandibular indices and biochemical markers. The aim of this study was to examine the diagnostic performance of dental panoramic radiography and biochemical markers of bone turnover in relation to BMD at the spine in a group of postmenopausal women. Subjects and methods An assessment of the number of lost teeth, mandibular cortical width (MCW) at the mental region and morphologic classification of mandibular inferior cortex (MIC grade) was performed on dental panoramic radiographs in a group of 141 postmenopausal women 38–81 years of age. BMD at the lumbar spine was measured by dual energy X-ray absorptiometry. BMD values were categorized as normal ( T-score greater than 1.0), and as indicative of osteopenia ( T-score −1.0 to −2.5) or osteoporosis ( T-score less than −2.5) according to the World Health Organization classification. Serum bone alkaline phosphatase (BAP) was measured with an enzyme immunoassay. Cross-linked N-telopeptides of type I collagen (NTx) corrected for creatinine secretion, was measured with a competitive-inhibition enzyme-linked immunosorbent assay ELISA. Results In our study, a decrease in MCW by 1 mm increases the likelihood of osteopenia or osteoporosis to 47% ( p-value < 0.05), having taken into consideration the effect of the years elapsed since menopause. The increase of alkaline phosphatase (ALP) per unit increase the likelihood of osteopenia or osteoporosis to 14% ( p-value < 0.05), having checked the effect of the years since menopause. A decrease in MCW by 1 mm increases the likelihood of moderately or severely eroded cortex to 97% ( p-value < 0.001). The increase in ALP per 1 unit increases the likelihood of moderate or severe erosion per 10% ( p-value < 0.05), taking into account the years since menopause. Conclusions Our results suggest that dentists have sufficient clinical and radiographic information that enables them to play a significant role in early diagnosis of osteoporosis in postmenopausal women. Panoramic radiographs and biochemical markers of bone turnover may be of value for prediction of individual bone loss and they may help in predicting risk of fracture in elderly women.

Experimental study of biomechanics after mandibular outer cortex osteotomy

To investigate the local changes of biomechanics after osteotomy of mandibular outer cortex in body and angle areas. Six minitype pigs at the age of 8 to 12 months were selected. The mandibular outer cortex that involves angle and part of body was removed in one side. The animals were killed 24 weeks after operation. Bone strut was taken from mandibular angle region bilaterally and sent for biomechanical test There was no biomechanical difference between the two angle areas of experimental and normal sides 24 weeks after mandibular outer cortex osteotomy (maximum load P > 0.05, rigidity P > 0.05). Mandibular outer cortex osteotomy had no influence on local biomechanics.

Relationship between mandibular inferior cortex and general bone metabolism in older adults

The purpose of this study was to investigate whether a link exists between the jawbone and general bone metabolism. The results of our study indicate that a mandibular inferior cortical erosion finding on dental panoramic radiographs is significantly associated with increased biochemical markers of bone turnover. The purpose of this study was to investigate whether a link exists between the jawbone and general bone metabolism. We measured values of serum bone-specific alkaline phosphatase (S-BAP) and urinary N-telopeptide cross-links of type I collagen (U-NTX). To evaluate the jawbone, we used mandibular inferior cortex (MIC) classification on dental panoramic radiographs. After 134 subjects were divided into three groups (C1: normal cortex, C2: mildly to moderately eroded cortex, C3: severely eroded cortex), we evaluated the relationship between S-BAP or U-NTX and MIC classification by Scheffe's multiple comparison test. A significant correlation was found between MIC classification and S-BAP (C1 vs. C2: p < 0.01, C1 vs. C3: p < 0.01, C2 vs. C3: NS). A significant correlation was found between MIC classification and U-NTX (C1 vs. C2: p < 0.01, C1 vs. C3: p < 0.001, C2 vs. C3: p < 0.01). The results of our study indicate that the mandibular inferior cortical erosion finding on dental panoramic radiographs is significantly associated with increased S-BAP and U-NTX levels. We suggest that there is an association between the jawbone and general bone metabolism.

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.

Do gender and torus mandibularis affect mandibular cortical index? A cross-sectional study

BackgroundThe interactions between torus and several factors such as age, gender, and dental status have not been studied comprehensively. The purpose of this study was to determine the effect of gender on the mandibular cortical index (MCI) and to investigate a possible association between torus mandibularis (TM) and MCI.MethodsThe study consisted of 189 consecutive patients referred to Department of Oral Diagnosis and Radiology of Hacettepe University within 30 workdays. Patients who did not have systemic disorders affecting bone density were included; and the age, gender, dental status and existing TM of the patients were recorded. Morphology of the mandibular inferior cortex was determined according to Klemitti's classification on panoramic radiographs.ResultsMCI was affected by age and gender (P < 0.05). No significant relationship was found between TM and MCI (P > 0.05).ConclusionIn the study population, MCI was affected by age and gender. As age increased, semilunar defects could be seen on the cortex of the mandible and MCI values increased. Women appeared to have higher MCI values than men.

Mandibular radiomorphometric measurements as indicators of possible osteoporosis in postmenopausal women

ObjectiveThe use of mandibular anatomic indicators on panoramic radiographs, i.e. the number of lost teeth, mandibular cortical width at the mental region (MCW), panoramic mandibular index (PMI), alveolar crest resorption degree (M/M ratio) and morphologic classification of the mandibular inferior cortex (MIC grade) can be useful in the evaluation of bone resorption in different age groups of women to determine the presence of osteoporosis. The purpose of this study was to assess the validity of mandibular radiomorphometric measurements and to determine the frequency of tooth loss in postmenopausal women. Subjects and methodsAn assessment of the number of lost teeth, MCW, PMI, M/M ratio and MIC grade was performed on dental panoramic radiographs in a group of 133 postmenopausal women 38–80 years-of-age.BMD at the lumbar spine was measured by dual energy X-ray absorptiometry. BMD values were categorized as normal (T-score greater than 1.0), and as indicative of osteopenia (T-score −1.0 to −2.5) or osteoporosis (T-score less than −2.5) according to the World Health Organization classification. ResultsIn our study when the T-score at the lumbar spine is decreased, the age of menopause is increased, and the MCW is decreased to a point of statistical significance. A decrease in MCW by 1mm increases the likelihood of osteopenia or osteoporosis to 43%, having taken into consideration the effect of the years elapsed since menopause. It was also shown that age, years since menopause, MCW value, and the number of teeth lost have a statistically important effect on the incidence of moderate or severe cortical erosion. Moreover, when the MCI is C2 or C3 (mild or severe erosions) the age is increased, the years since menopause are increased and the MCW is decreased to a point of statistical significance. As far as tooth loss is concerned, an increase by 1unit in the number of teeth lost, increase the likelihood of moderate or severe erosion to 6%, having taken into account the years elapsed since menopause. Our study also demonstrated that postmenopausal women tend to lose their teeth at an age older than 50 years. They usually lose the 1st and 2nd mandibular molars and the 1st and 2nd maxillary premolars. Loss of front teeth and canines occurs at an age older than 60 years (except for the lateral maxillary incisors). At a younger age they tend to lose the 2nd maxillary premolars more frequently than their mandibular counterparts. ConclusionsIn conclusion, panoramic radiographs constitute an integral part of almost every routine dental evaluation and can be useful for the early diagnosis of osteoporosis in postmenopausal women. Dentists have sufficient clinical and radiographic information that enables them to play a significant role in patient screening for osteoporosis.

Diagnosing osteoporosis by using dental panoramic radiographs: The OSTEODENT project

Measurement of cortical thickness and subjective assessment of cortical porosity on panoramic radiographs are methods previously reported for diagnosing osteoporosis. The aims of this study were to determine the relative efficacy of the mandibular cortical index and cortical width in detecting osteoporosis, both alone and in combination, and to determine the optimal cortical width threshold for referral for additional osteoporosis investigation. Six hundred seventy-one postmenopausal women 45 to 70 years of age were recruited for this study. They received dual energy x-ray absorptiometry (DXA) scans of the left hip and lumbar spine (L1 to L4), and dental panoramic radiographic examinations of the teeth and jaws. Three observers separately assessed the mandibular cortical width and porosity in the mental foramen region of the mandible. Cortical width was corrected for magnification errors. Chi-squared automatic interaction detection analysis (CHAID) software was used (SPSS AnswerTree, version 3.1, SPSS Inc., Chicago, IL). Chi-squared automatic interaction detection analysis showed that the cortical porosity was a poorer predictor of osteoporosis than mandibular cortical width. For the 3 observers, a mandibular cortical width of <3 mm provided diagnostic odds ratios of 6.51, 6.09, and 8.04. The test is therefore only recommended in triage screening of individuals by using radiographs made for purposes other than osteoporosis. When evaluating panoramic radiographs, only those patients with the thinnest mandibular cortices (i.e., <3 mm) should be referred for further osteoporosis investigation.

The Mandibular Cortex on Radiographs as a Tool for Osteoporosis Risk Assessment: The OSTEODENT Project

The aim of this study was to measure the accuracy of porosity of the mandibular cortex on dental panoramic radiographs (DPRs) in diagnosis of osteoporosis, alone and in combination with a clinical risk index. Six hundred seventy-one women (45–70 yr) were recruited in the study, and dual-energy X-ray absorptiometry of the hip and lumbar spine was performed. A clinical index of osteoporosis risk (OSIRIS) and a DPR were obtained for each subject. The cortical appearance on the DPR was classified using the mandibular cortical index (MCI) by 5 observers. receiver operating characteristic (ROC) curve analysis was performed with calculation of area under the ROC curve (AUC) and sensitivity and specificity at various thresholds. Complete data were available for 653 subjects, of whom 21.6% had osteoporosis. The AUC for OSIRIS was 0.838. When used alone as the diagnostic test, MCI AUC for the 5 observers ranged from 0.560 to 0.670, significantly less than OSIRIS. Intraobserver and interobserver repeatability of MCI assessment was inconsistent. We conclude that MCI has limited value for osteoporosis diagnosis, being most appropriate as a method of fortuitous case-finding.

CT and MRI findings of intraosseous schwannoma of the mandible: a case report

We report the radiographical findings of a rare case of intraosseous schwannoma of the mandible. The tumour that presented as a unilocular, well-defined, radiolucent lesion on plain radiography was located in the molar region. On CT, the tumour was a well-demarcated mass with no periosteal reaction and no destruction of the bone cortex. Destructive changes in the cortical wall of the mandibular canal by the tumour were observed on CT, but no evidence of dilatation and shift in the inferior mandibular canal was seen. MR imaging revealed that the mandibular canal was encased by the tumour as a solid mass without cystic parts. The signal intensity of the tumour was non-specific on MRI. Characteristics of intraosseous schwannoma in the mandible are the encasement of the canal by a well-demarcated tumour without periosteal reaction and the destruction of mandibular bone cortex. The destructive change of the inferior mandibular canal can be observed on CT and MRI. However, a biopsy is necessary to make the final diagnosis because of the non-specificity of the findings.

Prevalence of Osteoporotic Changes in Panoramic Radiographs of Patients showing Carotid Calcifications

ABSTRACT Objectives Atherosclerosis and Osteoporosis are two of the most prevalent chronic diseases in the western world. They share common risk factors and many studies suggest an association between arterial calcification and low bone mass possibly due to common etiology.(1-3) The aim of this pilot study is to study the prevalence of osteoporotic changes in patients showing evidence of carotid plaques on panoramic radiographs. Methods Of the panoramic radiographs done on dental school patients from 2004-2005, 24 radiographs showing frank evidence of carotid plaque were selected and reviewed for osteoporotic changes using the criteria by White et al.(4) Results 95% of our study patients showed evidence of osteoporotic changes in their mandibular cortex. Conclusions Given the results of our pilot study, it is important that dentists should screen for osteoporosis in patients showing carotid atherosclerosis.

Automated osteoporosis risk assessment by dentists: A new pathway to diagnosis

General dental practitioners use a vast amount of panoramic radiography in their routine clinical work, but valuable information about patients' osteoporotic status is not collected. There are many reasons for this, but one of the prime reasons must be the disruption involved in clinical routine with lengthy manual radiographic assessment. We have developed computer software, based on active shape modeling that will automatically detect the mandibular cortex on panoramic radiographs, and then measure its width. Automatic or semi-automatic measurement of the cortical width will indicate the osteoporotic risk of the patient. The aim of our work was to assess the computer search technique's ability to measure the mandibular cortical width and to assess its potential for detection of osteoporosis of the hip, spine and femoral neck. Mandibular cortical width was measured using the manually initialized (semi-automatic) method and, when assessed for diagnosing osteoporosis at one of the three measurement sites, gave an area under the ROC curve (A(z))=0.816 (95% CI=0.784 to 0.845) and for the automatically initialized searches, A(z)=0.759 (95% CI=0.724 to 0.791). The difference between areas=0.057 (95% Confidence interval=0.025 to 0.089), p<0.0001. For diagnosing osteoporosis at the femoral neck, mandibular cortical width derived from the manually initialized fit gave an area under the ROC curve (A(z))=0.835 (95% CI=0.805 to 0.863) and for the automatically initialized searches A(z)=0.805 (95% CI=0.773 to 0.835). The difference in A(z) values between active shape modeling search methods=0.030 (95% CI=-0.010 to 0.070), and this was not significant, p=0.138. We concluded that measurement of mandibular cortical width using active shape modeling is capable of diagnosing skeletal osteoporosis with good diagnostic ability and repeatability.

Trabecular and cortical bone as risk factors for orthodontic relapse

Dental relapse of the mandibular incisors after orthodontic treatment is a common problem, and few risk factors have been identified. The purpose of this case-control study was to evaluate whether the amount or the structure of mandibular bone affects the potential for postorthodontic mandibular incisor relapse. The subject sample was selected from the postretention database at the University of Washington. Subjects were chosen based on the availability of lateral cephalograms and mandibular periapical radiographs taken approximately 10 years postretention (T3). The mandibular incisor irregularity index (II) was measured on the T3 casts. Two groups were identified: subjects with the II greater than 6 mm (relapse or case) and those with the II less than 3.5 mm (stable or control). Once the case/control status was determined, the II was measured on models taken at the initial orthodontic examination (T1) and at the end of treatment (T2). Sixty relapse and 263 stable subjects were identified. Mandibular cortical thickness measured on both panoramic and lateral cephalometric radiographs was used to assess the amount of mandibular bone, and fractal analysis was used to analyze the trabecular bone structure around the mandibular incisors on the periapical radiographs. Logistic regression analyses were used to determine the association between dental relapse and significant bone parameters. The models were adjusted for potentially confounding variables (initial II, sex, age, and postretention time). The relapse subjects had a larger mean II at T1 and a longer postretention time than the stable subjects. The mean cephalometric mandibular cortical thickness was significantly smaller in the relapse group than in the stable group at T1, T2, and T3. There were no statistically significant differences in the trabecular structure of bone, as measured with fractal analyses, between the relapse and stable groups. These results indicate that patients with thinner mandibular cortices are at increased risk for dental relapse.

Low-grade central osteosarcoma of the mandible: a case study report

Low-grade central osteosarcoma is a rare type of osteosarcoma with peculiar clinical radiographic and microscopic features. The aim of this article is to report and discuss a case of low-grade central osteosarcoma in the mandible of a 42-year-old woman. The patient reported sensing mild pain and tooth mobility for a period of 4 years, despite continuous dental treatment. Radiographic evaluation showed a mixed radiopaque/radiolucenct lesion in the body, ramus, coronoid process, and condyle of the left side of the mandible. Destruction of the mandibular cortex in the area was also observed. After incisional biopsy, the patient underwent hemimandibulectomy. Microscopic findings showed a tumor exhibiting spindle cells with nuclear hyperchromasia and no mitotic activity, irregular osteoid formation, and soft tissue infiltration. The immunohistochemical analysis of the expression of Ki-67, Cyclin B1, and PCNA proteins (cellular proliferation markers) revealed a very low Ki-67+ and Cyclin B1+ cell index (mean 7% and 3%, respectively), but a moderate number of PCNA+ cells (mean 49%). The 2 years of clinical and imaging postoperative follow-up showed no evidence of recurrence. Clinicians should be aware of these lesions, because histopathologicially low-grade central osteosarcoma may be misinterpreted as fibrous dysplasia.

Diagnostic performance of general dental practitioners after lecture in identifying post-menopausal women with low bone mineral density by panoramic radiographs

Mandibular cortical erosion detected on panoramic radiographs may be useful for identifying post-menopausal women with low skeletal bone mineral density (BMD). The purposes of this study were to calculate the diagnostic performance of general dental practitioners (GDPs) who attended a lecture on identifying post-menopausal women with low BMD from findings on panoramic radiographs and to evaluate the influence of GDPs' age on diagnostic performance. After a 1 h lecture, 111 GDPs were asked to classify the mandibular cortex (normal or eroded) on panoramic radiographs obtained from 100 post-menopausal women who have had skeletal BMD assessment. Low BMD was defined as a BMD T score of -1.0 or less. Diagnostic performance was analysed by comparing two groups classified by mandibular cortex (women with normal cortex and women with any eroded cortex) with those classified by BMD (women with normal BMD and women with low BMD). The mean sensitivity, specificity, positive predictive value, negative predictive value, accuracy and likelihood ratio for a positive risk result were 73.0% (95% confidence interval [CI]; 71.3 to 74.7%), 49.0% (95% CI; 46.4 to 51.5%), 66.9% (95% CI; 66.0 to 67.8%), 57.0% (95% CI; 55.8 to 58.2%), 62.9% (95% CI; 62.1 to 63.7%) and 1.51 (95% CI; 1.44 to 1.58), respectively. GDPs' age did not influence diagnostic performance. Our results suggest that 73.0% of women who had low skeletal BMD can be identified by GDPs after a lecture on the use of panoramic radiographs as an aid in diagnosing low BMD; however, the diagnostic performance may not be influenced by GDPs' age.

Identification of Low Bone Mineral Density based on the Mandibular Cortex by Fuzzy Neural Network

Identification of Low Bone Mineral Density based on the Mandibular Cortex by Fuzzy Neural Network