Covid Mask Line. Dr.Y.S.Mohamed, published in den updates Dec 2020

COVID-mask-line: radiological phenomenon observed in occipitomental view of COVID 19 suspects with maxillofacial injuries. The authors have clearly explained the impact of COVID-19 to the practice of dentistry around the globe, and how to fulfil our obligation as a profession to ensure high standards of care to patients with urgent treatment needs in the current pandemic. This article basically focuses on robust facial protection in the practice of dentistry during the pandemic.

1 In the current COVID-19 setting, Oral and Maxillofacial Surgery (OMS) units and their supportive healthcare staff are obliged to provide care for patients whilst taking measures to ensure their own safety. We would like to highlight a simple radiological phenomenon that caught our eye which had occurred as a result of such unorthodox measures by healthcare staff. Sri Lanka has been under strict curfew for close to a month. OMS saw almost no maxillofacial fractures resulting from road traffic accidents during this time. Recently, in a village considered a COVID-19 hotspot, a man in a motorcycle breaking the curfew was chased by police. During the pursuit, the motorcyclist fell and sustained injuries including mandibular fractures. On examining his occipito-mental view (OM view) and postero-anterior mandible radiographs, the surgical team was intrigued by a linear radio-opaque artefact which ran across the radiograph. Further inquiry revealed that this artefact was due to the metal strip of the patient’s facemask, which we named as ‘COVID-mask-line’. As the patient was from a COVID-19 hotspot area, the radiographer has taken the radiograph with the man’s facemask on (Figure 1). At present, the law requires a facemask to be worn in public in Sri Lanka. As the radiography rooms are closed environments with air-conditioning, the radiographer had asked the patient to keep the mask on as a safety measure. This is contrary to the usual procedure where a radiographer would ask a patient to remove anything which would create an artefact on a radiograph. Since then, most radiographs we see happen to bear the ‘COVID- mask-line’ making it the ‘new normal’. Even though this is a seemingly innocent artefact, we would like to highlight that this radio-opaque line may obstruct the diagnosis of an infra-orbital fracture line in the OM view. Similarly, how the natural and hair extension produce ‘pseudo lesions’ and obstruct diagnosis in the maxillofacial region is described.2 These artefacts may be even questioned in medico-legal settings and may confuse undergraduates and inexperienced doctors. It will be necessary for an OMS to request an OM view radiograph ‘without the mask’, at least when suspecting an infra-orbital fracture. Interestingly, this also highlights the need for safety protocols for particular healthcare staff, such as radiographers.



  1. Samaranayake L, Shun Li DT. COVID-19:unmasking the facial protection paradigms. Dent Update 2020; 47: 644−650.
  2. Scheifele C, Lemke AJ, Reichart PA. Hair artefacts in the head and neck region. Dentomaxillofac Radiol 2003; 32: 255–257.

Dr YS Mohamed,  Consultant in Oral and Maxillofacial Surgery, National Hospital Kandy

Dr RMSHB Medawela, Lecturer in Oral Medicine and Radiology and Trainee in Oral and Maxillofacial Surgery

Dr NSS Jayasuriya, Consultant in Oral and Maxillofacial Surgery and Senior Lecturer in Oral Surgery, Faculty of Dental Sciences, University of Peradeniya, Peradeniya, Sri Lanka


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