Iatrogenic risk of osteonecrosis of the jaw? Bone substitutes for dental implants: a warning from Japan

Commercial bone substitutes that are widely used for bone augmentation for dental implants are predisposing factors in the development of osteonecrosis of the jaw (ONJ), overlooking this situation may lead to serious problems. Most of these materials are supplied as inorganic porous granules of calcium phosphate, which have characteristics that exceed the bone resorption ability of normal osteoclasts; therefore, they can be equally regarded as existing antiresorptive necrotic bony granules in the body, i.e., micro-ONJs. In addition, because dental implants directly contact the surrounding bone without the periodontium with immunoprotective functions, the mucosal penetration of the dental implant itself predisposes the underlying bone to the risk of infection, latent osteomyelitis, and ONJ. Therefore, the remaining porous granules surrounding the dental implant pose an additional iatrogenic risk, even though the tissue may appear superficially healthy. In an aging society, an individual who was systemically healthy at the time of implantation with bone augmentation could develop osteoporosis or cancer bone metastasis later in life. ONJ can occur more easily if an antiresorptive agent such as bisphosphonates or denosumab is administered without sufficiently recognizing an intraoral situation. If the latent risk is known in advance, the selection or use of medicines could be restricted. Such restrictions can result in other crucial issues that are beyond the discretion of the dentists; however, dentists have not been warned about such possibilities. The use of antiresorptive agents and bone substitutes for dental implants should be reconsidered to avoid numerous adverse events such as ONJ.