Imagine a 65-year-old woman visiting a dental clinic for a routine examination. She has no idea that her bones are gradually becoming thinner. There is no pain and no obvious symptom. Yet hidden within the dental X-ray taken by her dentist may be an important clue: the trabecular structure of her jaw is beginning to change, potentially signaling the early stages of osteoporosis.
This is the central finding of research conducted by drg. Silviana Farrah Diba, Sp.RKG., Subsp.RP(K), and a team from the Department of Oral and Maxillofacial Radiology, Faculty of Dentistry (FKG), Universitas Gadjah Mada. Published in the Saudi Dental Journal in 2021, the study proposed a simple yet promising approach: using digital periapical radiographs, an imaging tool already commonly available in dental clinics, to assess bone quality in postmenopausal women.
Why Can the Jaw Reflect Skeletal Health?
Osteoporosis is often a silent disease. The gold standard for diagnosis, dual-energy X-ray absorptiometry (DXA), is accurate but expensive and not available in all healthcare facilities. Moreover, DXA measures bone mineral density (BMD) but does not describe trabecular architecture—the sponge-like network within bone that is among the first structures to experience bone loss in postmenopausal women.
This is where periapical radiography comes in. The imaging technique has long been used by dentists to examine tooth roots and alveolar bone. The FKG UGM research team hypothesized that the same images could be analyzed further to assess the trabecular structure of the mandible and that changes in this structure might correlate with skeletal conditions elsewhere in the body.
The study involved 31 postmenopausal women aged 50 to 86 years, with a mean age of 65.2 years. All participants underwent DXA examinations at Dr. Sardjito General Hospital to assess femoral BMD (BMDF) and lumbar BMD (BMDL), after which they were classified into three groups: normal, osteopenia, and osteoporosis. Digital periapical radiographs were obtained from the right and left posterior mandibular regions at the UGM Dental Hospital. For each image, the researchers defined a 100 × 100-pixel region of interest (ROI), positioned approximately 2 mm from the apical tip of the mandibular first molar.
Trabecular analysis was performed using ImageJ software and the BoneJ plugin, which converted the radiographic images into black-and-white binary images. Two parameters were then measured: the percentage of bone area relative to total area (BA/TA) and trabecular thickness (Tb.Th).
Thinner Trabeculae, Telling Numbers
The results were striking in their simplicity. Both trabecular parameters, BA/TA and Tb.Th, showed significant differences between the normal and osteoporosis groups. In the osteoporosis group, mean Tb.Th was only 34.13 pixels, substantially lower than the 60.70 pixels observed in the normal group. BA/TA also declined from 0.525 in the normal group to 0.436 in the osteoporosis group.
Interestingly, the difference between the osteopenia and normal groups was not statistically significant. This suggests that trabecular changes became clearly detectable only once the condition had progressed to osteoporosis rather than during the osteopenic stage.
In terms of correlation, Tb.Th showed a stronger relationship with femoral BMD (r = 0.508; p < 0.05) than BA/TA (r = 0.3796; p < 0.05). This finding is consistent with anatomical characteristics: the femur and mandible have similar proportions of trabecular and cortical bone, unlike the lumbar spine, which is more heavily dominated by trabecular bone with a thin cortical layer.
“Dental radiography is a simple and affordable bone quality screening tool.” — Silviana Farrah Diba et al., Saudi Dental Journal, 2021
What Does This Mean for Everyday Dental Practice?
The practical implications are significant. If periapical radiographs can serve as an initial screening tool for bone quality, routine dental visits could potentially become opportunities for early osteoporosis detection, particularly in areas where access to DXA machines is limited.
The study does have limitations. Only three subjects were included in the normal group, compared with 22 in the osteopenia group. This uneven distribution limits the statistical strength of comparisons between groups. The researchers also noted that using a standardized square ROI may be less optimal than an ROI shaped to naturally follow the trabecular contours.
Future studies involving larger samples and ROIs covering multiple posterior mandibular teeth simultaneously have been proposed to strengthen the conclusions. Nevertheless, as an initial step, this study opens an intriguing pathway: tools already in dentists' hands every day may possess diagnostic potential that has not yet been fully explored.
Postmenopausal women may remain unaware of changes occurring in their bones until a fracture occurs. Dental X-rays, traditionally viewed as tools for examining tooth roots and caries, may one day serve as an early window into skeletal health—potentially providing a warning before it is too late.
Source DOI: https://doi.org/10.1016/j.sdentj.2021.07.003
Authors: Anny Anggraini; drg. Achmad Zam Zam Aghasy, M.Kes.
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