A role of oral bacteria in bisphosphonate-induced osteonecrosis of the jaw.

No consensus has yet been reached to associate oral bacteria conclusively with the etio-pathogenesis of bisphosphonate-induced osteonecrosis of the jaw (BONJ). Therefore, the present study examined the effects of oral bacteria on the development of BONJ-like lesions in a mouse model. In the pamidronate (Pam)-treated mice, but not control non-drug-treated mice, tooth extraction followed by oral infection with Fusobacterium nucleatum caused BONJ-like lesions and delayed epithelial healing, both of which were completely suppressed by a broad-spectrum antibiotic cocktail. Furthermore, in both in vitro and in vivo experiments, the combination of Pam and Fusobacterium nucleatum caused the death of gingival fibroblasts (GFs) and down-regulated their production of keratinocyte growth factor (KGF), which induces epithelial cell growth and migration. Therefore, in periodontal tissues pre-exposed to bisphosphonate, bacterial infection at tooth extraction sites caused diminished KGF expression in GFs, leading to a delay in the epithelial wound-healing process that was mitigated by antibiotics.

Oral epithelial dysplasia and squamous cell carcinoma following allogeneic hematopoietic stem cell transplantation: clinical presentation and treatment outcomes.

Late complications of allogeneic hematopoietic stem cell transplantation (HSCT) include a risk of secondary malignancies. Optimization for early diagnosis and treatment of oral premalignant or malignant lesions requires an assessment of potential predisposing risk factors. The medical records of patients who developed oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC) following allogeneic-HSCT were reviewed. Data on HSCT course, chronic graft-versus-host disease (cGVHD), and clinical outcome were recorded; landmark survival was calculated. Twenty-six patients with OED (n=8) and OSCC (n=18) were identified with a median follow-up of 26.5 and 21.5 months, respectively. Premalignant and malignant oral lesions were diagnosed at a median time of 2.5 and 8 years after HSCT, respectively. Chronic GVHD was present in 96% of patients and of these, 96% had oral involvement. Multifocal oral cancer was found in 28% of cases, and localized recurrence was observed in 44% of cases. These results suggest that oral cGVHD may be considered a potential risk factor for the development of OSCC following allogeneic-HSCT. The observation that oral cancers were frequently multifocal and recurred locally suggests that these cancers may be more aggressive. Vigilant follow-up and coordination of care are critical.