Serum bone and mineral metabolism markers in CBCT confirmed degenerative versus non-degenerative temporomandibular disorders

Abstract

Background Bone and mineral metabolism markers, particularly vitamin D, have been linked to temporomandibular disorders, but rarely to objectively documented joint degeneration. We examined whether serum bone and mineral metabolism markers, particularly 25-hydroxyvitamin D and magnesium, differ between temporomandibular disorder patients with versus without cone-beam computed tomography-documented osseous degeneration, and whether they track with condylar erosion severity.

Methods In this single-centre prospective cross-sectional study of consecutively enrolled patients, sixty temporomandibular disorder patients with cone-beam computed tomography-confirmed degenerative joint disease were compared with forty symptomatic patients without cone-beam computed tomography-detectable osseous degeneration. Serum 25-hydroxyvitamin D, magnesium, parathyroid hormone, calcium, phosphorus and alkaline phosphatase were measured. The two markers of primary interest were 25-hydroxyvitamin D, the established candidate, and magnesium, the novel one; all remaining comparisons were secondary or exploratory. Groups were compared with parametric or non-parametric tests as appropriate, and with a Firth penalized logistic regression adjusted for age and sex only.

Results Degenerative patients had lower 25-hydroxyvitamin D (16.4 versus 25.6 ng/mL) and magnesium (1.66 versus 2.00 mg/dL) and higher parathyroid hormone (p < 0.001, p < 0.001 and p = 0.005, respectively); calcium did not differ. No degenerative patient was vitamin D-sufficient, whereas the comparison group was predominantly insufficient. After adjustment, 25-hydroxyvitamin D and magnesium remained associated with degeneration independently of age and sex, whereas parathyroid hormone did not. Within degenerative patients, erosion severity correlated inversely with 25-hydroxyvitamin D and positively with parathyroid hormone; magnesium separated the groups but showed no severity gradient.

Conclusions Lower serum 25-hydroxyvitamin D and magnesium were associated with cone-beam computed tomography-documented joint degeneration independently of age and sex, most strongly for 25-hydroxyvitamin D; the magnesium association is the novel element and requires confirmation. Comparing degenerative with non-degenerative patients reduces confounding by the presence of the disorder itself, although the groups also differed in their DC/TMD profiles and adjustment was possible for age and sex only. These cross-sectional associations do not establish causality and do not support any screening or treatment recommendation; they identify bone and mineral metabolism status as a hypothesis for prospective study in temporomandibular joint osteoarthritis.