*3.1.5 Phosphate*

Phosphorus is an essential element and plays an important role in multiple biological processes, due to the fact that maintaining physiological phosphate balance is of crucial biological importance for bone health [17]. Approximately 85% of phosphorus is in the bone, primarily compounded with calcium (Ca2+), the most abundant mineral in hydroxyapatite (HAP) crystals deposited on the collagen matrix [18].

The importance of phosphate in periodontal disease has been observed in X-linked hypophosphatemia (XLH); this disease is a rare skeletal genetic illness in which increased phosphate in the kidney produces hypophosphatemia and prevents normal mineralization of the bone and bone dentine. In a study of 2017, it was observed that the frequency and severity of periodontitis increased in adults with XLH and that the severity varied according to the treatment of hypophosphatemia. Patients who benefited from early and continuous phosphate supplementation during childhood had less loss of periodontal attachment than patients with late or incomplete supplementation [19].
