|Year : 2016 | Volume
| Issue : 2 | Page : 205-211
Digital panoramic radiography: An aid in the early detection of osteoporotic signs
Y Udaya Sindhu1, Y Samatha2, A Ravikiran2, P Rama Swamy1, Abhishek Singh Nayyar3, B Kartheeki3
1 Department of Oral Medicine and Radiology, St. Joseph Dental College and Hospital, Eluru, Andhra Pradesh, India
2 Department of Oral Medicine and Radiology, Sibar Institute of Dental Sciences, Guntur, Andhra Pradesh, India
3 Department of Oral Medicine and Radiology, Saraswati-Dhanwantari Dental College and Hospital, Post Graduate Research Institute, Parbhani, Maharashtra, India
|Date of Web Publication||20-Dec-2016|
Abhishek Singh Nayyar
44, Behind Singla Nursing Home, New Friends' Colony, Model Town, Panipat - 132 103, Haryana
Source of Support: None, Conflict of Interest: None
Background: Osteoporosis is a worldwide problem demanding attention in the modern world. In the last four decades, numerous research teams have reported oral radiographic findings associated with osteoporosis. The preponderance of the evidence shows that the jaws of subjects with osteoporosis show reduced bone mass and altered morphology. A number of mandibular cortical indices (MCIs) have also been developed to allow quantification of mandibular bone mass and identification of osteoporosis. Aims and Objectives: The aim of the present study was to measure various radiomorphometric indices and/or, mandibular cortical indices (MCIs) on digital panoramic radiographs (Orthopantomographs [OPGs]) of postmenopausal females; to assess the bone mineral density (BMD) of postmenopausal females using dual energy X-ray absorptiometry (DEXA); and to compare the radiomorphometric indices on digital panoramic radiographs with BMD values and thereby assessing the efficacy of digital panoramic radiographs in detecting mandibular osteoporotic changes so as to screen osteoporosis. Materials and Methods: One hundred postmenopausal females were randomly selected from the outpatient department. All the patients were explained about the need for the study. Informed consent was taken, and a detailed case history was obtained. After subjecting the patients to digital panoramic radiography, the patients were taken for BMD evaluation using DEXA scans. Statistical Analysis: The data obtained were subjected to statistical analysis using SPSS version 14. P < 0.05 was considered statistically significant. ANOVA with post hoc Tukey's test, Chi-square test, Pearson correlation coefficient, and Spearman correlation coefficient were used for statistical analysis. Results: Klemetti index showed that a patient with C3 cortical appearance had a low BMD. Among the quantitative indices, mental index, panoramic mandibular index, antegonial index, and gonial index, showed significantly lower values among the osteoporotic group. Conclusion: Digital panoramic radiographs (OPGs) have a significant role in the initial screening of elderly females for early osteoporotic changes.
Keywords: Bone mineral density, digital panoramic radiography, dual energy X-ray absorptiometry, mandibular cortical indices, osteoporosis
|How to cite this article:|
Sindhu Y U, Samatha Y, Ravikiran A, Swamy P R, Nayyar AS, Kartheeki B. Digital panoramic radiography: An aid in the early detection of osteoporotic signs. Arch Med Health Sci 2016;4:205-11
|How to cite this URL:|
Sindhu Y U, Samatha Y, Ravikiran A, Swamy P R, Nayyar AS, Kartheeki B. Digital panoramic radiography: An aid in the early detection of osteoporotic signs. Arch Med Health Sci [serial online] 2016 [cited 2017 Mar 27];4:205-11. Available from: http://www.amhsjournal.org/text.asp?2016/4/2/205/196208
| Introduction|| |
Osteoporosis is a worldwide problem demanding attention in the modern world. Although osteoporosis is known since ages, dramatic increase in the numbers related to osteoporotic fractures is drawing researchers from various fields into this silent disease. The burden of osteoporosis is because of its clinical outcome: Osteoporotic fractures, which are generally recognized as low-trauma fractures resulting from low bone mineral density (BMD). Asia is the region expecting the most dramatic increase in hip fractures during coming decades; by 2050, one out of every two hip fractures worldwide will occur in Asia. One out of eight males and one out of three females in India suffer from osteoporosis, making India one of the largest affected countries in the world. In most Western countries, the peak incidence of osteoporosis occurs at about 70–80 years of age, while in India, it may afflict at age 50–60. For a person, over 50 years living in a developing country, the lifetime risk of sustaining a fracture has been estimated at 50% for females and 20% for men. Dual energy X-ray absorptiometry (DEXA) is the most reliable technique to determine BMD. The American College of Preventive Medicine (ACPM) has stated that screening with BMD testing for osteoporosis is recommended in females aged 65 years and over, and men aged 70 years and over. ACPM also recommends that younger postmenopausal females and men aged 50–69 years should undergo BMD testing if they have at least one major or two minor risk factors for osteoporosis. However, BMD testing for all such individuals is not practical in many countries where DEXA is not widely available. The role of digital panoramic radiographs in identifying systemic diseases has drawn considerable interest in the field of research across the globe. The fact that dental radiographs are regularly made on a large fraction of the adult population makes their potential use, as a marker of skeletal health, an exciting avenue of research. The incidental findings detected on digital panoramic radiographs may be used to identify patients who have no awareness of their low BMD and would benefit from BMD testing. In the last four decades, numerous research teams have reported oral radiographic findings associated with osteoporosis. The preponderance of this evidence shows that the jaws of subjects with osteoporosis show reduced bone mass and an altered morphology. A number of mandibular cortical indices (MCIs) have been developed to allow quantification of mandibular bone mass and identification of osteoporosis. A study was conducted on 100 postmenopausal females with evaluation of a set of radiomorphometric indices on digital panoramic radiographs and correlated with bone density status using DEXA which is considered to be the gold standard for diagnosing osteoporosis. The aims and objectives of the study were to measure the various radiomorphometric indices on digital panoramic radiographs (orthopantomography [OPGs]) of postmenopausal females; to assess the BMD of postmenopausal females using DEXA; and to compare the radiomorphometric indices on digital panoramic radiographs (OPGs) with BMD values and thereby assessing the efficacy of digital panoramic radiographs (OPGs) in detecting the initial mandibular osteoporotic changes.
| Materials and Methods|| |
Source of data
One hundred postmenopausal females were randomly selected from the outpatient department (OPD).
- Inclusion criteria:
- Female patients within the age group of 45–70 years.
- Exclusion criteria:
- Patients on any specific medications or hormones (oral contraceptive pills, corticosteroids, or hormone therapy) which are known to have adverse effects on bone metabolism
- Patients with severe periodontal diseases and conditions resulting in bone loss in the jaw bones
- Patients with known systemic diseases that would affect bone metabolism such as Paget's disease, renal osteodystrophy or, osteogenesis imperfect and various cancers with or without bony metastases, etc.
All the patients were explained about the need for the study. Informed consent was taken, and a detailed case history was obtained from each patient. After subjecting the patients to digital panoramic radiography (OPGs), the patients were taken for BMD evaluation using DEXA scans.
Measurement of bone mineral density
Examination of the BMD was done using DEXA scans. The data regarding menopausal status and age were recorded at the time of DEXA measurement. The dual X-ray absorptiometry of lumbar spine (L1–L4) and left hip were performed using Hologic (Model: Explorer, 12.6 version) machine. The system used an X-ray tube with a switched pulsed dual energy of 100 and 150 kVp at a frequency of 50 Hz. The scan speed was 0.321 mm/s. The patients were classified according to the World Health Organization (WHO) classification based on T-scores which are the expression of BMD values in terms of standard deviations from the normal value of a female, young adult mean.
Assessment of mandibular indices (mandibular cortical indices) using digital panoramic radiographs (OPGs)
All the patients were subjected to digital panoramic radiography (OPGs) with lead apron using Kodak 9000C machine operated at 70 kVp and 8–12 mA and for 14.2 s. A set of indices, both qualitative and quantitative, were calculated as described below using SIDEXIS XG software (Sirona Dental Systems Gmbh 2003-2011; Fabrikstrasse 31, 64625 Bensheim; Germany) by two different observers blinded of each other's readings. To maintain standardization, both the observers had calculated the values only on the left side.
Morphology of mandibular inferior cortex (MIC): Klemetti et al. classified morphology of MIC by observing the mandible distally from mental foramen as follows:
- Class I: The endosteal margin of the inferior cortex is smooth;
- Class II: The endosteal margin shows semilunar defects (lacunar resorption) with formation of endosteal cortical residues, 1–3 layers thick; and
- Class III: The cortex is obviously porous with dense endosteal residues.
Quantitative indices included the mental index (MI), panoramic mandibular index (PMI) as done by Benson et al., panoramic analysis, antegonial index (AI) as described by Ledgerton et al., gonial angle (GA), antegonial angle (AA), and antegonial depth (AD).
The data so obtained was subjected to statistical analysis using SPSS version 14 (SPSS Inc., 233 South Wackier Drive, 11th Floor, Chicago, USA). P < 0.05 was considered statistically significant. Comparison of the mean scores was done using ANOVA with post hoc Tukey's test. Comparison of MCI scores was done using Chi-square test. Pearson correlation coefficient was used to correlate age with indices, and Spearman correlation coefficient was used to correlate age with MCI. Interobserver reliability was calculated and was in the range of 0.952–0.982 for the various indices.
| Results|| |
The radiomorphometric indices were categorized as qualitative and quantitative indices. Qualitative index included the MCI as described by Klemetti et al. and quantitative indices measured were MI, PMI, AI, AD, AA, gonial index (GI), and GA. MCI which describes the mandibular inferior cortical shape has been categorized into C1, C2, and C3 as suggested by Klemetti et al. In this study, out of 100 patients, 22 had C1 cortex, 54 had C2 cortex, and 24 had C3 cortex. The mean age of patients with C1 cortex was 51.05 years, with C2 cortex was 53.89 years and with C3 cortex was 59.29 years. Chi-square test revealed that normal subjects had significantly higher proportions of category C1 and C2 whereas osteopenic and osteoporotic subjects had higher C2 and C3 scores (P < 0.001). Out of the 24 normal patients, 41.7% had C1 cortex, and 58.3% had C2 cortex. In this study, none of the patients with normal BMD had a C3 cortex (0%) [Figure 1]a,[Figure 1]b,[Figure 1]c and [Table 1]. According to the study, the range of MI for normal subjects came out to be 3.01–5.21 mm, for osteopenic patients, was 2.50–4.50 mm, and for osteoporotic subjects, was 2.13–4.73 mm. Statistically significant difference was present in relation to MI and BMD with lower scores in relation to osteoporotic group (P < 0.001) [Figure 2] and [Table 2]. PMI was calculated according to the method described by Benson et al. The PMI values were in a range of 0.29–0.56 for the normal subjects, 0.24–0.61 for the osteopenic patients and 0.20–0.41 for osteoporotic subjects. The mean PMI value for normal subjects was found to be 0.41, for osteopenic subjects were 0.35 while for osteoporotic patients was 0.28. Statistically significant difference was found between the mean PMI values of normal, osteopenic and osteoporotic females with osteoporotic patients having smaller PMI ratios (P < 0.05) [Figure 2] and [Table 2]. AI was calculated as described by Ledgerton et al. The mean AI values for normal subjects were 2.70 mm, for osteopenic subjects was 2.89 mm while for osteoporotic individuals was 2.40 mm. Statistically significant difference was found with lower values in the osteoporotic group (P = 0.007) [Figure 3] and [Table 2]. With respect to the AD, the mean values did not show any statistically significant correlation with BMD (P = 0.418) [Figure 4] and [Table 2]. In case of AA, the results were not found to be statistically significant with a P = 0.354 [Figure 4] and [Table 2]. There was a statistically significant difference among the three BMD groups in this case. Lower GI values were seen in osteoporotic group than those from the normal group and this difference reached a significant level in our study with a P = 0.001 [Figure 3] and [Table 2]. Furthermore, no statistically significant correlation could be found between GA and BMD status (P = 0.748) [Figure 3] and [Table 2]. Spearman's correlation coefficient was used to correlate age with MCI and the various other indices used wherein a significant positive correlation with age was found for MCI scores (r = 0.36 and P < 0.001) while in case of all other quantitative indices, only a weakly negative correlation with age for PMI scores was seen (r = −0.244 and P = 0.015) [Table 3]. In addition, a comparison of mean age with MCI (MCI values) and BMD revealed both the relations to be statistically significant [Table 4].
|Table 1: Means with standard deviation of mandibular cortical index in various groups using Chi-square test|
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|Figure 2: Cropped panoramic radiograph showing mental index, panoramic mandibular index calculated.|
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|Table 2: Means with standard deviation of the various quantitative indices in various groups using ANOVA with post hoc Tukey's test|
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|Figure 3: Cropped panoramic radiograph showing antegonial index, gonial index, and gonial angle calculated.|
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|Figure 4: Cropped panoramic radiograph showing antegonial depth, antegonial angle calculated.|
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|Table 3: Comparison of mean age with various indices using Pearson's and Spearman's rho Correlation Coefficients|
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|Table 4: Comparison of mean age with mandibular cortical index and bone mineral density using ANOVA with post hoc Tukey's test|
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| Discussion|| |
The present day, world is facing many health-related challenges of which osteoporosis has come into focus because of its potential in causing fractures and their associated morbidity. A large number of elderly females suffer with this grave disease which often remains undiagnosed. Osteoporosis has been defined as a disease characterized by low bone mass and microarchitectural deterioration of the bone tissue, leading to enhanced bone fragility and consequent, increase in fracture risk. The general clinical diagnosis of this disease is performed by observing the formed fractures with little trauma in bones that have occurred due to a reduction in BMD. Cardinal radiographic features of osteoporosis in the skeleton as a whole include generalized osteopenia that is most often prominent in the spine, thinning, and accentuation of the bone cortices and loss of secondary trabeculation. Low bone mass can be evaluated using various methods including quantitative computed tomography, magnetic resonance imaging, quantitative ultrasonography, single photon absorptiometry, dual photon absorptiometry, single X-ray absorptiometry, and dual X-ray absorptiometry/DEXA. Among these, DEXA is considered as gold standard and was approved by WHO. Although osteoporosis, and its sequelae, may be seen throughout the skeleton, there are three common sites of fracture: The vertebral bodies, the distal forearm, and the femoral neck. Consequently, research is being focused on these specific skeletal areas. However, there has been a growing interest among dental researchers in the possible relationship between systemic osteoporosis and BMD in the mandible. The mandibular cortical bone undergoes a resorptive activity in osteoporotic subjects, and its manifestations can be detected on dental panoramic radiographs. These evidence reveal that observing thinning of the MIC and changes in the morphology of the endosteal margin of the cortex can be utilized as simple and available tools in the detection of probable low BMD, and referring high-risk patients for, further, assessment by bone densitometric analysis to prevent the further progression of the disease process. Radiologic features of osteoporosis in the jaws include relative radiolucency of both jaws and reduced definition of the cortices. As there is a lack of practicality in assessing mandibular osteoporotic changes as elsewhere in the general skeleton, clinicians have started to focus on some mandibular panoramic indices such as the MCI, mandibular cortical width, PMI, AI, AA, AD, GI, and GA, bone quality index, relative bone density, and simple visual methods for the identification of elderly individuals who require a BMD assessment. A study was conducted on 100 postmenopausal females between the ages of 45–70 years. A study sample was selected randomly from the OPD. After subjecting the patient to digital panoramic radiographs, the study sample was subjected to DEXA scans. MCI, mandibular cortical thickness and PMI, AI, AA, AD, GI, and GA were taken into consideration for the study. Two observers blinded of each other's readings calculated the indices. According to the study, a clearly observable deterioration of skeletal status as age increased was present because the mean age of osteoporotic individuals was higher than the nonosteoporotic groups. Similar interpretation was also given by Dutra et al. and Alonso et al. Klemetti et al. were the first to describe the mandibular cortical shape classifications. Our study revealed that normal individuals had significantly higher proportions of category C1 and C2 whereas osteopenic and osteoporotic had higher C2 and C3 scores (P < 0.001). In this study, it was observed that none of the patients with C3 cortex were normal. Thus, our study suggests a strong correlation between thinner cortices (C3) and low BMD. The results of our study regarding MCI were in agreement with those of Taguchi, Ledgerton et al., Bollen et al., Drozdzowska et al., Yasar et al., and Uysal et al. who had conducted MCI on varying sample sizes and ethnicities and had confirmed the efficacy of MCI in detecting patients with low BMD. However, literature shows that few studies like the ones conducted by Horner and Devlin  did not find any correlation between MCI and BMD. In this study, the mean values of MI were found to be significantly less in osteoporotic individuals than in osteopenic and normal individuals (P < 0.001). Our study was in agreement with the studies conducted by Taguchi, Klemetti et al., Horner and Devlin  and Vlasiadis et al. who had, also, found the values of MI in patients with low BMD to be low. However, studies conducted by Drozdzowska et al. and Yasar et al. showed no correlation between MI and osteoporosis. Ledgerton et al. found that the mean cortical width (3.96 mm) in British postmenopausal females with a low BMD (T-score of 21.0 or less) was about 84% of the mean cortical width (4.73 mm) in those with a normal BMD. Taguchi et al. had found that the mean cortical width (3.75 mm) in Japanese postmenopausal females with a low BMD was also about 84% of the mean cortical width (4.45 mm) in those with a normal BMD. Our study had shown that the mean cortical width was 83.56% of the mean cortical width of normal individuals. Thus, our study recommends the reliability of MI in the screening of osteoporosis. PMI was first described by Benson et al. and was later modified by Wical and Swoope. The mean PMI values were significantly lower in osteoporotic individuals in the present study (P < 0.005). The results were in accordance with the studies done by Ledgerton et al., Drozdzowska et al., Rao et al. Gulsahi et al., Dagistan and Bilge, Marandi et al., Hastar et al., and Johari Khatoonabad et al. AI was first described by Ledgerton et al. They described the advantages of AI over other indices. In the present study, the mean values of AI were found to be higher in osteopenic individuals than in the osteoporotic individuals. However, there was a statistically significant difference between the AI values of osteoporotic and normal individuals with lower values among osteoporotic group compared to normal subjects (P = 0.007). The results of the study were in accordance with the works done by Ledgerton et al., Dutra et al., Alonso et al., Dagistan and Bilge  and Leite et al. Bras et al. first described the thickness of the mandibular angle cortex as a useful diagnostic tool in patients with metabolic diseases such as renal osteodystrophy. Thereafter, several researchers have evaluated whether cortical width of the mandibular angle, subsequently named the gonion index (GI), is an effective screening tool for identifying elderly, especially postmenopausal females, with undetected osteoporosis. Statistically significant difference was found among the three BMD status with lower values in the osteoporotic group (P = 0.007). Our results were consistent with the studies done by Law et al. and Alonso et al. who, also, had found significantly lower values in osteoporotic females when compared to the nonosteoporotic females. Few studies, done by Ledgerton et al. and Leite et al., however, showed a negative correlation between skeletal status and GI values. Literature, also, showed that the values of GI were insignificant because of lack of precision and the values being extremely low, this being a cause of variable measurements. The present study, however, showed a positive correlation. In the present study, there was no statistically significant difference as far as GA was concerned among the three skeletal groups (P = 0.748). The findings of the present study were in accordance with the studies conducted by Dutra et al., Leite et al., Casey and Emrich  and Ghosh et al. Also, in the present study, no statistically significant relation could be observed between the mean AAs and depths with BMD status and the results of the present study were found to be in accordance with the studies conducted by Leite et al. and Ghosh et al., however, the study conducted by Dutra et al. had found the antegonial region to be a great predictor in detecting the risk of osteoporosis by evaluating AD and AA.
| Conclusion|| |
Osteoporosis is a grave disease and its associated morbidity has been increasing across the world. An early detection can be of profound significance as the turmoil related to fractures can be minimized. Researchers had found that the panoramic radiographs taken routinely by the dental surgeons can be helpful in the screening of osteoporosis.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]