The risk of Schneiderian membrane perforation and the postoperative complications of the sinus floor elevation surgery were evaluated for patients with and without history of COVID-19 infection.

COVID-19 induced chronic sinusitis with subsequent increased Schneiderian membrane thickness could increase the risk of its perforation during the sinus floor elevation. The aim of the study is to compare the incidence of Schneiderian membrane perforation and the postoperive complications of the sinus floor elevation in patients with and without history of COVID-19.

Inclusion Criteria:

• 4 mm or less residual alveolar bone height
• Age more than 18 years
• Highly motivated patients

Exclusion Criteria:

• Patients who suffer from any systemic disease
• sinus pathosis other than sinusitis induced covid 19
• Patients under any medication that may interfere with the normal bone healing