BACKGROUND: Dental restorative materials containing silver-mercury compounds have been known to induce oral lichenoid lesions. OBJECTIVES: To determine the frequency of contact allergy to dental restoration materials in patients with oral lichenoid lesions and to study the effect of removal of the materials on the lesions. RESULTS: Forty-five patients were recruited in three groups of 15 each: Group A (lesions in close contact with dental materials), Group B (lesions extending 1 cm beyond the area of contact) and Group C (no topographic relationship). Thirty controls were recruited in two groups of 15 individuals each: Group D (oral lichenoid lesions but no dental material) and Group E (dental material but no oral lichenoid lesions). Patch tests were positive in 20 (44.5%) patients. Mercury was the most common allergen to elicit a positive reaction in eight patients, followed by nickel (7), palladium (5), potassium dichromate (3), balsam of Peru, gold sodium thiosulphate 2 and tinuvin (2) and eugenol (1), cobalt chloride (1) and carvone (1). Seven patients elicited positive response to more than one allergen. In 13 of 20 patients who consented to removal of the dental material, complete healing was observed in 6 (30%), marked improvement in 7 (35%) and no improvement in 7 (35%) patients. Relief of symptoms was usually observed 3 months after removal. LIMITATIONS: Limited number of study subjects and short follow up after removal/replacement of dental restoration materials are the main limitations of this study. CONCLUSION: Contact allergy to amalgam is an important etiologic factor in oral lichenoid lesions and removal of restorative material should be offered to patients who have lesions in close proximity to the dental material.
BACKGROUND: Dental restorative materials containing silver-mercury compounds have been known to induce oral lichenoid lesions. OBJECTIVES: To determine the frequency of contact allergy to dental restoration materials in patients with oral lichenoid lesions and to study the effect of removal of the materials on the lesions. RESULTS: Forty-five patients were recruited in three groups of 15 each: Group A (lesions in close contact with dental materials), Group B (lesions extending 1 cm beyond the area of contact) and Group C (no topographic relationship). Thirty controls were recruited in two groups of 15 individuals each: Group D (oral lichenoid lesions but no dental material) and Group E (dental material but no oral lichenoid lesions). Patch tests were positive in 20 (44.5%) patients. Mercury was the most common allergen to elicit a positive reaction in eight patients, followed by nickel (7), palladium (5), potassium dichromate (3), balsam of Peru, gold sodium thiosulphate 2 and tinuvin (2) and eugenol (1), cobalt chloride (1) and carvone (1). Seven patients elicited positive response to more than one allergen. In 13 of 20 patients who consented to removal of the dental material, complete healing was observed in 6 (30%), marked improvement in 7 (35%) and no improvement in 7 (35%) patients. Relief of symptoms was usually observed 3 months after removal. LIMITATIONS: Limited number of study subjects and short follow up after removal/replacement of dental restoration materials are the main limitations of this study. CONCLUSION: Contact allergy to amalgam is an important etiologic factor in oral lichenoid lesions and removal of restorative material should be offered to patients who have lesions in close proximity to the dental material.