Intraoral contact allergy to materials used in dental practice. A critical review.

Intraoral contact allergy reactions are clinically poorly differentiated and understood, and are not very commonly described in the specialized literature. Although such reactions appear to be scantly relevant, evidence suggests that they may be more frequent than previously believed. No single or specific clinical picture of intraoral contact allergy exists, though lichenoid reactions appear to be the most common manifestations. Epicutaneous patch testing, together with the clinical manifestations, constitute the most widely used diagnostic approach in such situations. Metals used in dental practice--particularly amalgams and gold--are the most commonly reported causes of intraoral allergic reactions, though hypersensitivity to resins is increasingly mentioned in the literature, as a consequence of their increasingly widespread use. The systematic intraoral elimination or substitution of materials inducing cutaneous hypersensitivity has recently been questioned, while on the other hand it not possible to discard an allergic component in some nonspecific stomatological disorders. The present study offers clinicians an evidence-based update of current knowledge in this field.