An underdiagnosed manifestation: Mandibular bone loss in primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a metabolic bone disorder characterized by elevated parathyroid hormone (PTH) levels, leading to decreased bone mineral density and increased risk of osteoporosis. While oral manifestations are frequently reported, mandibular bone loss and its relationship with systemic bone health remain inadequately characterized. This study aimed to investigate mandibular bone loss in PHPT patients and its association with osteoporosis.

In this single-center, case-control study, 226 participants (111 PHPT patients and 115 age- and sex-matched healthy controls) were enrolled. Clinical, laboratory, and imaging data were collected, including panoramic radiographs to assess mandibular bone loss using the Parathyroid Mandibular Index (PMI) and the Klemetti Index (KI). Dual-energy X-ray absorptiometry (DXA) was used to assess bone mineral density and diagnose osteoporosis. Correlation and logistic regression analyses were performed to explore associations between mandibular indices and osteoporosis.

PHPT patients had significantly lower PMI values and more advanced KI categories compared to controls, indicating greater mandibular bone loss. Also, in the PHPT group, patients with osteoporosis had worse PMI and KI values than those without osteoporosis. Correlation analysis showed that PMI scores positively correlate with skeleton t scores. Multivariate logistic regression analysis identified PMI as an independent predictor for osteoporosis in PHPT patients.

Mandibular bone loss, particularly indicated by lower PMI values, is a potential early marker for osteoporosis in PHPT patients. To our knowledge, our study is one of the first to highlight the significance of mandibular bone loss in PHPT patients and its correlation with osteoporosis. Routine panoramic radiographs, commonly obtained in dental practice, could provide valuable adjunctive information for osteoporosis risk assessment in this population.