Atypical and Late-Developed Sinus Graft Complications Following Maxillary Sinus Augmentation: Successful Management with Guided Bone Regeneration.

Complications that occur after maxillary sinus floor augmentation (MSA) can be divided into early and late complications. Early complication is a side effect that occurs during the MSA procedure or during the initial healing period. Usually, late complication refers to a side effect that occurs after 3 weeks of MSA.