Skin irritation is often encountered in children undergoing orthodontic treatment with facemask. Since treatment success is highly dependent on patient cooperation and wearing time of the device, discomfort or pain related to skin changes can result in reduced treatment effects. The present study aimed to investigate the prevalence, pattern, and factors related to skin irritation during facemask therapy.
The results showed that 43.5% of the patients experienced some form of skin reaction during the treatment. There are no comparable reports in the literature, which investigated the prevalence of skin changes associated with facemask therapy. Most of the studies regarding adverse skin reactions during orthodontic treatment deal with nickel allergy caused by nickel containing appliances.11–13 Furthermore, only little is reported about reactions caused by extraoral appliances, while the majority of these reports are about nickel component of headgear.14–18
While most of the adverse reactions caused by intraoral appliances are immunological reactions to allergens such as nickel, latex or other components of orthodontic devices, the skin changes in facemask patients are often due to pressure on the skin or friction.19–21 Although rare, allergic contact dermatitis in association with facemask has also been reported.22,23 Allergic contact dermatitis is a pruritic, eczematous eruption, which may be acute (blistering, weeping and/or edema) or chronic (lichenified or scaly plaques).24 This reaction is typically well demarcated and localized to the site of skin that comes in contact with the allergen.24 The skin changes observed in the present study were not characteristic for allergic contact dermatitis (Fig. 1). Furthermore, they only affected small areas in the lower part of the chin, but not the forehead that also had contact with the facemask. Therefore, allergic contact dermatitis can be excluded as a differential diagnosis for the skin changes. There are few possible causes that could explain the affected skin in the present study. These are, for instance, irritant contact dermatitis or atopic diathesis in correlation with epidermal barrier dysfunction.
Irritant contact dermatitis is a localized, non-immunological, cutaneous inflammatory reaction with polymorphous clinical features. In acute cases, erythema, scaling, edema, vesiculation and erosions can occur. In chronic cases, lichenification, hyperkeratosis and fissures can be observed. Frictional irritant contact dermatitis is a subtype of irritant contact dermatitis, resulting from repeated low grade frictional trauma, such as wearing a facemask like in the present study.24 25
Atopic diathesis, encompassing atopic dermatitis, allergic rhino-conjunctivitis, food allergy, eosinophilic esophagitis, and asthma, is commonly associated with epidermal barrier dysfunction.26 The barrier function of the skin resides primarily in the stratum corneum of the epidermis.27 The epidermal barrier function can be measured by parameters such as transepidermal water loss (TEWL) and stratum corneum hydration (SCH).26 TEWL evaluates the diffusion of condensed water through stratum corneum, and a greater TEWL is often associated with skin barrier impairment.26,28 SCH describes the water content of the stratum corneum, and a lower value is associated with skin barrier dysfunction.26 There are a number of studies that suggest that TEWL decreases with age, implicating weaker skin barrier in younger age. This may explain the increased frequency of skin changes in younger age groups observed in the present study. However, in children with eczema, a decrease of SCH is reported regardless of gender and age, while no significant changes in terms of SCH could be observed in children without eczema.29 These findings suggest that the difference in skin condition among participants in our study might also depend on the presence of atopic diathesis.
An interesting finding of this study is the more frequent occurrence of skin irritation in female patients. Epidermis is the outermost layer of the skin with the function of providing a protective barrier, for example against mechanical stimuli or potentially harmful environmental agents, and regulating loss of water and electrolytes.30 Depending on the thickness of the epidermis, the protective and regulative function of the skin can vary. Several studies reported the epidermis to be thicker in men than in women.30–33 This suggests that male skin might have better protective function of the epidermis against mechanical stress and frictional forces compared to female skin, reflecting the results of the present study.
In the present study, the severity of malocclusion and chin morphology were not found to be significantly correlated with the occurrence of skin irritation, although there was some tendency towards increased skin problems in patients with more severe malocclusion. On the other hand, the presence of complaints in the TMJ area had a statistical significance. From these results, it can be inferred that skin irritation is more closely associated with the amount of force applied than the individual anatomical variations. The facemask appliance is fitted to sit passively on the forehead and chin, while the protraction force is generated by the elastics. The amount of force is adjusted by the size of the elastics and position of the crossbar. In other words, the chin position related with prognathic mandible usually does not affect the amount of force applied. However, the total amount of stress exerted on the chin and TMJ area may vary depending on the appliance design and the direction of force application.7,34,35 Skin irritation and TMJ complaints may both result from excessive force delivered by the appliance.36 On the other hand, skin irritation can also occur secondary to TMJ pain. When the mandible is forced posteriorly, the condyle can press against the sensitive retrodiskal bilaminar zone, causing pain or discomfort.37,38 For pain relief the patient may develop a habit of mandibular thrusting, which increases pressure on the chin area and also the risk for skin irritation. However, the cause-and-effect relationship between the occurrence of skin irritation and TMJ complaints is not clear and needs to be further investigated in future studies.
The gradual development of 3D technology has opened up new possibilities in the production of orthodontic devices. With the help of 3D face scanner and 3D printer orthodontic facemask can be fully customized. Such customization can improve device fit and patient comfort.39 Furthermore, it can also contribute to the reduction of skin irritation, if the chin cup is modified in shape and material to fit the individual anatomy and skin type. However, the need for additional equipment and high costs for the manufacture of customized facemask makes its application in every patient difficult. As an alternative to full customization, the chin cup component of the prefabricated facemask can be modified to prevent skin irritation. A chair-side customization using polyvinyl siloxane for a better fit and stability has been suggested for better distribution of stress in the chin area.40 Furthermore, lining of the internal surface with skin-friendly materials such as cotton cloth, hydrocolloid or foam could also help reduce the pressure or friction caused by facemask. In addition, patients and parents should be informed of possible skin reactions prior to facemask therapy, and provided with sufficient guidelines regarding the correct use of facemask, and the management in case of skin problems during the treatment.