We conducted a study designed to investigate the clinical factors correlated with the spread of an odontogenic infection to the deep spaces of the head and neck. We also analyzed the treatment modalities for this and their outcomes. The study retrospectively examined all patients admitted in 2009 and 2010 to the General Hospital of Attica "KAT" with maxillofacial infections of odontogenic origin. The patients' case records were reviewed according to predefined inclusion and exclusion criteria and the relevant data were collected. The data were analyzed statistically. The study involved 212 patients with a mean age of 40.8 y. Of these, 59.9% reported using oral antibiotics, usually (35.4%) without prescription. Moderate or poor oral hygiene was present in 78.3% of the study patients. The percentage of incompatible use of antibiotics due to non-compliance was 13.4%. Non-compliance indicates that these patients failed to follow the daily dosage or the dosing intervals of a prescribed antibiotic or they stopped an antibiotic due to an adverse reaction. Incision and drainage was required in 63.2% of the study patients, and 46.2% required extraction of the tooth responsible for their infection. A statistically significant association was documented between fever on admission and a prolonged hospital stay. No major complications were encountered among the study patients. Odontogenic infections remain a common cause of morbidity. Poor oral hygiene, self-medication, inadequate utilization of antibiotics, lack of treatment of the causative tooth, delayed presentation at the hospital, and bacterial resistance to empirically administered antibiotics appear to correlate with the spread of odontogenic infections. Incision and the evacuation of pus when indicated, intravenous antibiotic therapy, modification of the antibiotic regimen according to the results of sensitivity tests, and early treatment of the causative tooth constitute a successful management protocol for odontogenic infections.