Hawley retainer and lichenoid reaction: a rare case report

BACKGROUND: Oral lichenoid reaction (OLR) is a type IV cell-mediated immune response in the oral cavity. There is an established relationship between various dental materials and OLR, but few cases reports reported the occurrence of a lichenoid reaction in association with the use of a Hawley retainer. CASE PRESENTATION: A female patient (twenty years of age) has been complaining of a reddish painful area on the tongue, which started one year ago and has been increasing in size over time. The patient completed orthodontic treatment two years ago and has been using a Hawley retainer for orthodontic retention since then. After performing histological analysis and patch test, the lesion was diagnosed as a lichenoid reaction to the Hawley retainer. Topical corticosteroids were prescribed, and the patient was asked to stop using the retainer and followed for six months. CONCLUSIONS: It is difficult to diagnose lichenoid lesions and even more challenging to differentiate between OLP and OLR, therefore it is essential to do a full intraoral and extraoral examination. OLL can occur in association with Hawley retainer, which we believe could be because it is made of an acrylic based material. Generally, OLL resolves after removal of the cause.