A patient who smokes and uses oral contraceptives undergoes a mandibular molar extraction. Which factor most significantly increases the risk of alveolar osteitis (dry socket)?

Smoking is the strongest independent risk factor for alveolar osteitis (dry socket) because nicotine and tobacco smoke increase fibrinolytic activity, disrupting the blood clot. The sucking motion of smoking also creates negative intraoral pressure that can mechanically dislodge the clot. While oral contraceptives slightly increase risk by elevating estrogen-mediated fibrinolysis (particularly with estrogen-containing pills), smoking has a markedly stronger and more consistent association with dry socket. Poor oral hygiene increases the risk of postoperative infection but is a weaker predictor of dry socket specifically.