Although all the theories reported of the etiopathology of dry socket still need to be established, some evidence has suggested that an interaction exists between excessive local trauma and bacterial invasion. This association results in the formation of plasmin and, consequently, fibrinolysis inside the socket. In 1989, Catellani stated that the pyrogens secreted by the bacteria are indirect activators of fibrinolysis in vivo. Catellani studied the effectiveness of those pyrogens on the treatment of thromboembolic disease, injecting the products intravenously. An interesting fact is that dry socket does not occur until after the first postoperative day. The explanation is that the blood clot contains antiplasmin, which must be consumed by the plasmin before disorganization of the clot.
Surgical extraction that includes the presence of flaps and sectioning of the tooth with an osteotomy level have also been referred to as factors contributing to dry socket. Birn considered that the trauma resulting from extraction, as well as aggressive curettage, might harm the alveolar bone cells, causing inflammation of the alveolar osseous medulla and release of cell mediators to the alveolus, where they cause fibrinolytic activity, increasing the risk of dry socket. This has been highlighted by studies in which less-experienced surgeons had a greater incidence of complications after the extraction of nonerupted third molars compared with more experienced surgeons. Also, dry socket was the most common complication observed in these studies. Investigators have studied the relationship between the reason for extraction and the incidence of dry socket. They found a 21.9% incidence of dry socket when the extraction was considered therapeutic (presence of infection and caries) compared with 7.1% for prophelactic extractions (without any symptoms).
The presence of dental and osseous remains within the socket has also been considered a possible cause of dry socket. In 1969, Simpson demonstrated through microscopic studies of monkeys that those fragments are commonly observed in any extraction and do not necessarily cause problems, although they might cause inflammation and some delay in the chronology of the alveolar repair. Bone and dentin components such as sialoprotein and phosphoprotein have been reported to trigger leukocyte chemoattraction and the production of inflammatory cytokines, which characteristically upregulate bone resorption and downregulate bone formation.
Vasoconstrictors, which are present in local anesthetics, have also been considered contributing factors for the etiopathogeny of dry socket. This affirmation was contested, however, because patients undergoing extraction with local anesthesia without local infiltration have also developed dry socket. Other investigators have also observed that patients who underwent intraligamentary anesthesia did not present with a greater incidence of dry socket compared with patients who had undergone anesthesia exclusively by regional anesthesia.
Poor oral hygiene and consequent alveolar contamination is also an important factor for the onset of dry socket. This relationship was supported by reports of this complication in patients with poor oral hygiene and/or pre-existing local infection, such as pericoronitis and severe periodontal disease.
Concerning the involvement of bacteria in the pathogenesis of dry socket, investigators have observed the
presence of Streptococcus