Osteoporosis therapy in patients with inflammatory rheumatic diseases and osteonecrosis of the jaw

Mechanism of bisphosphonate-related osteonecrosis of the jaw (BRONJ) revealed by targeted removal of legacy bisphosphonate from jawbone using competing inert hydroxymethylene diphosphonate

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) presents as a morbid jawbone lesion in patients exposed to a nitrogen-containing bisphosphonate (N-BP). Although it is rare, BRONJ has caused apprehension among patients and healthcare providers and decreased acceptance of this antiresorptive drug class to treat osteoporosis and metastatic osteolysis. We report here a novel method to elucidate the pathological mechanism of BRONJ by the selective removal of legacy N-BP from the jawbone using an intra-oral application of hydroxymethylene diphosphonate (HMDP) formulated in liposome-based deformable nanoscale vesicles (DNV). After maxillary tooth extraction, zoledronate-treated mice developed delayed gingival wound closure, delayed tooth extraction socket healing and increased jawbone osteonecrosis consistent with human BRONJ lesions. Single cell RNA sequencing of mouse gingival cells revealed oral barrier immune dysregulation and unresolved proinflammatory reaction. HMDP-DNV topical applications to nascent mouse BRONJ lesions resulted in accelerated gingival wound closure and bone socket healing as well as attenuation of osteonecrosis development. The gingival single cell RNA sequencing demonstrated resolution of chronic inflammation by increased anti-inflammatory signature gene expression of lymphocytes and myeloid-derived suppressor cells. This study suggests that BRONJ pathology is related to N-BP levels in jawbones and demonstrates the potential of HMDP-DNV as an effective BRONJ therapy.

Oral Rehabilitation With Dental Implants and the Importance of a Preventive Evaluation for Osteonecrosis of the Jaws Associated With Medications

Osteonecrosis of the jaw is a possible oral complication resulting from antiresorptive therapies, such as bisphosphonates (Bfs). Although the etiology is not entirely clear, it has been shown to be dependent on several factors, with the traumatic stimulation caused by the placement of teeth implants indicated as one of the predisposing factors to this pathology. The indications and preventive methods for performing these procedures have been questioned, making it essential to determine the proper protocols. Thus, the present study aims to discuss the risks of the development of osteonecrosis in patients undergoing dental implant surgery who use Bfs as well as to discuss related local and systemic factors and possible methods for preventing this side effect. The study also aims to present a clinical case of an osteopenic patient who used Bfs and underwent rehabilitation through implants according to specific protocols, which resulted in successful treatment.