The REDUCTION trial is a prospective multicentre cohort study conducted at the level I emergency departments of the University Medical Center Groningen, Isala hospital (Zwolle, The Netherlands) and the level II trauma center Nij Smellinghe hospital (Drachten, The Netherlands). The increased availability of Computed Tomography (CT) in the emergency department is leading to an overuse for patients with suspected maxillofacial injury. The use of a clinical decision aid could lead to more expedient use of diagnostic imaging within this population of patients. Therefore, all maxillofacial trauma patients admitted to the emergency department are included in this trial if the consultation is within 7 days after trauma. Both maxillofacial trauma patients admitted to CT scan and patients without a radiological confirmed diagnosis are included. The research protocol was approved by the institutional review board of the University Medical Center Groningen (Groningen, The Netherlands). Informed consent was waived as patients are treated according to the standards of care. Upon admission, each patient with maxillofacial injury will be allocated as a midfacial or mandibular trauma. During physical examination, either by the emergency physician or surgical resident, a pre-defined selection of clinical parameters will be assessed focussing on the assessment of potential presence of fractures in the maxillofacial region. The standardization of this examination will be ensured using a pocket map and easy accessible online instructional video's. The clinical parameters, fracture likelihood and physical examination findings will be structurally reported in electronic health record software using a smart tool dedicated for maxillofacial injury. Data regarding patient demographics, mechanism of injury, concomitant injury, diagnostic outcome and radiation dose parameters will be derived from the medical records.