An implant patient shows a 15 mm thickening of the maxillary sinus membrane on imaging. The appropriate step is to:

Correct answer: C. Refer to an otolaryngologist (ENT)

• A. Incorrect – operating into pathologic mucosa risks complications/failure.
• B. Incorrect – irrelevant to sinus pathology.
• C. Correct – significant sinus membrane thickening suggests sinus pathology (e.g., chronic sinusitis); ENT evaluation/clearance is appropriate before sinus augmentation.
• D. Incorrect. A 15 mm sinus membrane thickening warrants ENT evaluation of the underlying sinus pathology before any sinus-floor surgery; empiric antibiotics with delayed imaging is not the appropriate first step.