INTRODUCTIONWretched and unforeseen occurrences can occur during dental treatment. Most common being anaphylactic reactions to local anesthetics, allergic reactions to dental materials, antibiotics, nonsteroidal anti-inflammatory drugs, etc.1 A patient with orofacial edema arouses several possibilities in the dental practitioner’s mind. However, rare diseases may mimic or present similarly to common diseases, resulting in a “medical mystery.” Such diagnostic quandary can be disturbing for both the patient and the dentist.The resin-based restorations as well as their constituents must satisfy the biocompatibility testing as they are indicated for a long time period in the mouth and can cause allergic reactions in the form of urticaria, swelling, rash, contact allergy and rhinorrhea. The clinical features include burning, pain and dryness of mucosa, nonspecific stomatitis and cheilitis. Composites, latex gloves, local anesthetic agents, endodontic materials, impression materials, and metals are some of dental materials suspected with biocompatibility issues.The demand for esthetics has increased the application of the acid-etch technique thus increasing the use of phosphoric acid as an etchant. 30 to 40% phosphoric acid is the most used concentration however; the chemical is potentially caustic in higher concentrations. In a review of local and systemic responses related to the effects of dental restorative materials, Stanley found that inappropriate acid etching procedures with 50% phosphoric acid could lead to ulceration and sloughing of oral tissues.2 To date, adverse reactions caused by its contact with the oral mucosa are rare except for the references to such occurrences only in oral pathology texts.3-5Allergic contact dermatitis (ACD) is a non-infectious inflammatory disease of the skin characterized by a delayed hypersensitivity reaction (type IV T-cell-mediated) due to contact with methacrylate present in bonding agents.6,7 The first case report that follows showed an adverse reaction to etchant thus indicating the need of taking precautions to prevent its spillage in undesired areas while the purpose of second case report was to promote the awareness regarding the allergies due to methacrylate in bonding agents when placed on gloved hands during composite restorations.