Is Prolonged Mask Wearing Associated With Orofacial Pain?

During the pandemic of coronavirus disease 2019 (COVID-19), the Centers for Disease Control and Prevention recommended surgical N95 respirators (also referred as a medical respirator) to be used by healthcare providers for protection from airborne and fluid transmission. With the prolonged use of face masks and surgical respirators, new issues of mask-associated orofacial pain have emerged for oral and maxillofacial surgeons and should be investigated for proper management and prevention.

Healthcare workers have reported masks-associated orofacial pain, specifically in areas of temporalis (94.5%), zygomaticus (96.1%), nasalis (96.9%), and auricularis muscle (93.8%) with the use of N95 masks with a mean of 5.9 hours per day.¹ The onset of the pain is as immediate as less than 60 minutes after donning, and it usually resolves spontaneously within 30 minutes after doffing of the masks. Such orofacial pain can be secondary to excessive compression caused by straps of masks, the pressure from which irritates superficial sensory nerves, especially trigeminal and occipital¹ branches, leading to incidence of orofacial pain, including headache. Orofacial pain associated with mask wearing is often reported by healthcare workers related to masks with designs of ear loop and head strap. The tight seal N95 respirators with head strap compress and create tension of masticatory muscles, including masseter, temporalis, and the pterygoid muscles, while those with ear loop style impose significant pressure on the eminence of concha, leading to the risk of ear deformity and pain radiation to other orofacial muscles.

Moreover, another study reported orofacial pain secondary to temporomandibular joint disease (TMD). The authors suggest there is a higher risk of TMD for populations with prolonged use of masks (>8 hours), especially for females.² In the study, detailed history, including frequent jaw movement for mask adjustment, lifestyle or parafunctional habits, examination, and imaging information were obtained to confirm the presence of muscle or arthrogenous pain. Notably, disk displacement with reduction is reported to be significantly higher in those with frequent jaw movement related to masks.² The findings can be attributed to the limitation of custom sizes available for mask users with different facial profiles and nasal bridge shapes, whereby repeated jaw motions are needed to adjust the mask position (Fig 1 ). These motions include frequent maximal mandible protrusion and rotation, imposing continuous strain to extracapsular ligaments and eventually associative pain. While TMD and its multifactorial pathoetiology are related to facial morphology, dental occlusion, and psychological and neuromuscular disease, the authors suggest adding mask-related repetitive jaw movements into consideration of the management of TMD as a psychosocial factor. Although a contradictory finding was reported that they found significant decrease in resting temporalis anterior and masseter muscle activity during mask wearing, the observation was only made throughout a period of 4 hours, and only healthy, young females were included in the study,³ making it insufficient to draw a conclusion on correlation between mask wearing and muscle activity.

Figure 1.

Temporomandibular joint activities during frequent mouth opening and protrusive jaw movement for frequent mask adjustment (created with BioRender.com).

It is also important to note that other contributory factors on mask-associated orofacial pain and TMD could be parafunctional activities and physiological changes, including hypoxia and hypoxemia associated with prolonged wearing of masks. Indeed, dental students and dentists who wear N95 respirators during work reported an increase in TMD symptoms and parafunctional movements such as repetitive mouth opening and closing, bruxism, lateral excursions or protrusive movements compared to daily life when without mask.⁴ Although the association between mask wearing and daytime bruxism is pathophysiologically unclear, underlying reasons can be related to stress with prolonged hours of work with the use of masks, anxiety from discomfort and even claustrophobic reactions from the tight seal of N95 respirators. On the other hand, some dentists reportedly have a significant drop in oxygen saturation 1 hour after wearing N95 respirators, which later increased after another hour but was still lower than the baseline.⁵ In such cases, changes in breathing pattern and jaw movements, including mouth breathing and bruxism, can collectively contribute to the development of orofacial pain including TMD.

Several questions still need to be addressed, as there is limited evidence evaluating the following considerations: (1) assessing facial muscle activity during and/or after prolonged mask wearing, (2) investigating the effects of mask-wearing on orofacial muscles and temporomandibular joints, and (3) exploring the difference between types of masks (N95/KN95/FFP2 respirators vs regular medical masks; masks with ear loop vs masks with head strap/overhead vs tie-on/tie-back surgical masks) regarding their effects on orofacial muscles and temporomandibular joints.

Wearing masks has become our daily norm as a result of the COVID-19 pandemic. The N95 respirators used for added protection are distinctive from loose-fitting regular surgical masks due to their tight facial fit, enhanced filtration against 95% or more of 0.3-μm particles, and proven previous success in the prevention of respiratory viral infections including severe acute respiratory syndrome coronavirus 1 and 2 infection. While there are no data on the incidence of orofacial pain and TMD related to mask-wearing prior to the COVID-19 pandemic, with the current prolonged and frequent use of N95 respirators especially, orofacial pain associated with masks should be a topic of discussion considering its clinical relevance. Currently, TMD can be managed conservatively with nonsteroidal anti-inflammatory drugs, hot compressions, soft diet, night guard, and BOTOX injections. It would also be worth considering for manufacturers to design custom masks for people with different mandibular shapes and nasal bridge heights to reduce the need to frequently adjust mask with repeated jaw motions. Yet, there is still much that is unclear regarding mask-related orofacial pain and TMD. There needs to be more studies to address the pathophysiology of mask-related TMD and to develop preventive measures aimed at protecting the 59 million healthcare workers, including oral and maxillofacial surgeons who wear masks for long hours on a daily basis, as well as non-healthcare workers whose jobs require long hours of mask wearing.