Biological complications associated with aluminum ion release in implant-supported provisional restoration: a case report

Implant-supported provisional restorations are widely used during the osseointegration period and may remain in contact with peri-implant tissues for extended periods. Material biocompatibility is therefore critically important. Aluminum alloys have occasionally been used for provisional frameworks due to their low cost and ease of fabrication; however, their biological safety in the oral environment remains poorly documented. This report describes a case of peri-implant osteonecrosis associated with an aluminum framework used in a provisional restoration. A 53-year-old heavy smoker with severe periodontitis received staged full-arch implant rehabilitation with a mandibular implant-supported provisional restoration using an aluminum framework. Six months later, one implant failed early with obvious sequestrum formation. A 30-day immersion test showed sustained high-level aluminum ion release from the patient’s used framework, while titanium framework released only trace levels. ICP analysis detected 18.6 µg/g aluminum in the sequestrum, markedly higher than 3.3 µg/g in normal alveolar bone. Aluminum frameworks can release considerable aluminum ions, which may represent a potential risk factor for peri-implant osteonecrosis and tissue-damage in susceptible patients. Although multiple risk factors may be involved, these findings highlight the importance of prudent material selection for provisional restorations, particularly in high-risk patients.