Prevalence and pathogenesis of dental and periodontal lesions in children with X-linked hypophosphatemic rickets.

Aim: To assess the prevalence and to investigate the pathogenetic mechanisms of dental and periodontal lesions in children with X-linked hypophosphatemic rickets (XLH) examined at diagnosis or during treatment.
Methods: Nine children with XLH (age 7.2 +/- 3.3 years) were enrolled in the study (at diagnosis, n = 2; during treatment with oral inorganic phosphate salts combined with 1,25-dihydroxyvitamin D3, n = 7). Oral examination was performed according to the evidence of carious and gingival lesions. Decayed or filled teeth (dft) index for primary teeth, and the decayed, missing, or filled teeth (DMFT) index for permanent teeth was assessed. All patients with a history of spontaneous dental abscesses underwent orthopantomography examination.
Results: d/D ranged from 0 to 9 and f/F from 0 to 3. DMFT/dft index was 0 in the three youngest patients. One patient had enamel hypoplasia and two had enamel dyschromic alterations. Six out of nine patients (67%) had a history of spontaneous fistulae as a consequence of periapical abscesses occurring in the absence of dental decay or history of injury. In these patients, orthopantomographies showed enlarged pulp chambers associated with prominent pulp horns extending up to the dentino-enamel junction in both primary and permanent dentition.
Conclusion: XLH patients show some peculiar dentinal abnormalities. Treatment prevents only in part dental and periodontal lesions. Genetic mechanisms have a main role in causing defective dentin mineralisation.