Objectives: The aim of this study was to evaluate available knowledge and identify knowledge gaps within the field of oral and maxillofacial surgery, by systematically collecting and evaluating systematic reviews. Twelve specific domains were selected: surgical removal of teeth, antibiotic and corticosteroid prophylaxis, orofacial infections, dental and facial trauma, orthognathic surgery, reconstructive surgery, benign tumors, cysts, premalignant lesions, oral complications of treatment of malignant tumors, hyperbaric oxygen therapy, temporomandibular joint surgery, cost effectiveness of different surgical treatments, and ethics. Methods: The literature search, covering four databases, was conducted during September 2014: PubMed, The Cochrane library, Centre for Reviews and Dissemination and EBSCO dentistry and oral science source. Retrieved systematic reviews were quality assessed by AMSTAR. Results: In all, 1,778 abstracts were identified, of which 200 met the inclusion criteria. Forty-five systematic reviews were assessed as of high to moderate quality. The results disclosed some existing evidence in a few domains, such as surgical removal of teeth and implant survival after sinus lifts. However, in all domains, the search revealed a large number of knowledge gaps. Also of concern was the lack of data regarding health economics and ethics. Conclusions: In conclusion, there is a need for well-conducted clinical research in the fields of oral and maxillofacial surgery.