Influence of normocalcemic primary hyperparathyroidism in bone density alterations of the jaws in patients with periodontitis.

Background: Normocalcemic Primary Hyperparathyroidism (NPHPT) is a complex syndrome that causes excess secretion of parathyroid hormone (PTH) from the parathyroid glands. PTH in bone activates the function of osteoclasts, to increase bone resorption and thus increase plasma calcium levels. Given that periodontitis generates osteolytic lesions and has a high prevalence in adults, both pathologies could share etiopathogenic mechanisms, although no studies have been found to date that have investigated this. Therefore, the aim of the study was to evaluate the bone density, periodontal status and biochemistry variables to determinate if there is a relationship between both pathologies.

Material and methods: A case-control study was carried out with 86 cases (NPHPT) and 87 controls. Bone density was evaluated through computed tomography, measured in Hounsfield units, in seven Regions of Interest. Periodontal status and biochemical variables, such as marker hormones of bone metabolism (25 OH vitamin D and PTH), were analyzed. A Student's t test, bivariate correlations were performed and the OR was calculated.

Results: NPHPT patients are more susceptible to changes in the pattern of bone remodeling due to elevated serum levels of PTH and a decrease in 25OH vitamin D under conditions of normocalcemia. The 58.9% of cases group had periodontitis Stage IV, 27% Stage III, 9.45% Stage II and 8.1% with Stage I. Control group showed a 32% periodontitis Stage IV, 39% Stage III, 8.82% have Stage II and 16.2% Stage I.

Conclusions: There was an association between NPHPT and periodontitis, with patients with NPHPT showing a 1.78 (OR) greater probability of suffering from periodontitis. Our biochemical results showed that the increase in PTH and the decrease in 25OH VIT-D were associated with loss of bone density and these patients presented advanced periodontitis.