Title: X linked hypophosphataemic rickets in adulthood: Recurrent dental abscesses and implant failure
Abstract:
Background: X-linked hypophosphataemic rickets (XLH) is the most common inherited cause of rickets and results in chronic renal phosphate wasting and impaired mineralisation of bone and dentine. Dental manifestations are well recognised, with spontaneous, non-carious dental abscesses occurring in a substantial proportion of affected adults. However, guidance regarding dental implant placement in adults with XLH remains limited.
Case Report: A 35-year-old male with XLH was referred to the endodontic department with recurrent facial swelling and a diffuse buccal swelling associated with the lower left molar region. He had a history of recurrent spontaneous dental abscesses affecting multiple teeth, despite regular attendance with his general dental practitioner and good oral hygiene. His XLH was not being medically treated with phosphate, active vitamin D or FGF23-targeted therapy. Radiographic and clinical examination demonstrated multifocal periapical pathology affecting teeth that were otherwise clinically and radiographically unremarkable prior to presentation, with no identifiable history of caries or trauma. Multiple teeth subsequently developed spontaneous pulp necrosis and periapical infection, requiring sequential root canal treatment. Apical surgery was required for several teeth, including management of apical granulation tissue and a mandibular anterior bone fenestration. Progressive mobility and infection ultimately resulted in extraction of three mandibular incisors, followed by socket preservation and grafting. Three dental implants were subsequently placed using fully guided protocols. Although good primary stability was achieved at placement, two implants subsequently demonstrated complete loss of osseointegration. One implant placed in native bone was found to have silently lost integration at the stage of definitive restoration, while a second implant placed in grafted bone developed a draining sinus and gross mobility. A third implant placed concurrently in the same grafted site remains clinically stable.
Conclusion: This case demonstrates the significant dental burden associated with untreated XLH in adulthood, characterised by recurrent spontaneous, non-carious dental abscesses and subsequent tooth loss. It also highlights the potential risk of impaired osseointegration in patients with untreated metabolic bone disease. Current international guidance recommends medical optimisation before implant surgery in patients with XLH. Recurrent unexplained dental abscesses should prompt consideration of an underlying phosphate metabolism disorder and, in patients with known XLH, dental management should be undertaken in conjunction with appropriate medical optimisation.
