A study is presented of 85 cases of perforation to the maxillary sinus closed within 48 h after appearance. All cases were treated with the Rehrmann buccal flap procedure or primary suture. 1 patient developed an oro-antral fistula and sinusitis and a further 3 patients developed sinusitis postoperatively. A detailed presentation of the cases with complications is made. The relationship between a non-infectious sinus and the treatment results is discussed and the importance of antibiotic treatment in addition to surgical intervention is stressed.