Spontaneous bone formation after sinus graft infection control: a case report and review of the literature

BACKGROUND: Spontaneous bone formation in the maxillary sinus is a rare phenomenon, commonly attributed to multiple factors that influence the space between the sinus floor and mucosa, thereby promoting the formation of blood clots in this region. Nevertheless, these factors are not yet fully elucidated. CASE PRESENTATION: In January 2022, a 20-year-old male patient underwent bone-added osteotome sinus floor elevation with simultaneous implant placement at the maxillary left first molar. However, 10 days after surgery, the patient presented with left infraorbital pain, peri-implant suppuration, and a loose implant. Cone beam computed tomography (CBCT) images showed sinus opacification and reduced density of the peri-implant bone and graft materials. The implant and graft materials were then removed, and the socket was thoroughly irrigated with copious chlorhexidine solution and saline, then meticulously covered with iodoform gauze. The pain symptoms were alleviated a week after implant removal. The maxillary sinus remained opaque on CBCT images, with thinning of the lateral sinus wall and reduced bone height. After 3 months, clinical examination revealed no significant abnormalities in the soft tissues. Radiographic evaluations showed new bone formation within the maxillary sinus, accompanied by mucosal thickening and the disappearance of opacities. 2 years later, CBCT images displayed spontaneous bone formation in the maxillary sinus. Finally, an implant was placed, and the restoration was completed successfully. CONCLUSIONS: This case report underscores the occurrence of spontaneous bone formation in the maxillary sinus after resolution of a postoperative sinus graft infection, ultimately enabling successful reimplantation at the same site. In analogous cases, prolonging the healing period may be beneficial to promote natural self-healing.