title: Causes and timing of delayed bleeding after oral surgery.
abstract: OBJECTIVE
  This study examines a cohort of patients who suffered bleeding requiring hemostatic intervention after oral surgery. The reasons for bleeding and the interval between surgery and onset of bleeding are investigated.
  
  
  METHODS
  Between 1998 and 2009, 1,819 cases were eligible for this retrospective study. Factors (independent parameters) influencing the interval (dependent variable) were analyzed using negative binomial count regression models (NegBin II). The significance of each regressor's effect was tested using Wald's test and the total effect using likelihood ratio test.
  
  
  RESULTS
  Of the patients examined, 1,101 (60.1 %) did not take anticoagulants, 394 (21.5 %) took phenprocoumon, 233 (12.7 %) took acetylsalicylic acid, 33 (1.8 %) took clopidogrel, 17 (0.9 %) took more than one anticoagulant, and 78 (4.3 %) had a congenital blood disorder. After simple tooth extraction, 95.3 % suffered bleeding; 69.7 % of extractions were performed in the molar region. Later that day of surgery, 66.0 % of all patients showed bleeding. The bleeding interval was significantly prolonged by anticoagulant therapy with phenprocoumon, by congenital clotting disorders.
  
  
  CONCLUSIONS
  Normal tooth extractions are underestimated for their risk for postoperative bleeding, especially in the molar region. Anticoagulant therapy or congenital blood disorders present oral surgeons with a further challenge.
  
  
  CONCLUSIONS
  Performing surgery before midday allows surgeons managing postoperative bleeding themselves for a better patient satisfaction. Intensified information about correct postoperative behavior is crucial. Prolonged blood coagulation should intensify follow-up checks. Patients with congenital blood disorders and patients at high risk for bleeding with the need for substitution of platelets or clotting factors should receive inpatient care. More potent, local applicable coagulant agents are required for these patients.
authors.affiliation: University Clinic of Cranio-, Maxillofacial and Oral Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria, cornelia.czembirek@meduniwien.ac.at.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Czembirek
authors.forename: Wolfgang Paul
authors.initials: WP
authors.lastname: Poeschl
authors.forename: Christina
authors.initials: C
authors.lastname: Eder-Czembirek
authors.forename: Michael Bernhard
authors.initials: MB
authors.lastname: Fischer
authors.forename: Christos
authors.initials: C
authors.lastname: Perisanidis
authors.forename: Philip
authors.initials: P
authors.lastname: Jesch
authors.forename: Kurt
authors.initials: K
authors.lastname: Schicho
authors.forename: Angel
authors.initials: A
authors.lastname: Dong
authors.forename: Rudolf
authors.initials: R
authors.lastname: Seemann
mesh_terms: D015331:Cohort Studies; D005260:Female; D006470:Hemorrhage / Q000209:etiology*; D006801:Humans; D008297:Male; D019647:Oral Surgical Procedures / Q000009:adverse effects*; D011183:Postoperative Complications