Dental technicians are exposed to methyl methacrylate(MMA) and hard metal dusts while working, and several cases of hypersensitivity pneumonitis caused by the exposure have been reported. The authors experienced a case of hypersensitivity pneumonitis in a female dental technician who had 10 years’ work experience and report the case with clinical evidence.

The patient’s work, personal, social, and past and present medical histories were investigated based on patient questioning and medical records. Furthermore, the workplace conditions and tools and materials the patient worked with were also evaluated. Next, the pathophysiology and risk factors of pneumonitis were studied, and studies on the relationship between hypersensitivity pneumonitis and a dental technician’s exposure to dust were reviewed. Any changes in the clinical course of her disease were noted for evaluation of the work-relatedness of the disease.

The patient complained of cough and sputum for 1 year. In addition, while walking up the stairs, the patient was not able to ascend without resting due to dyspnea. She visited our emergency department due to epistaxis, and secondary hypertension was incidentally suspected. Laboratory tests including serologic, electrolyte, and endocrinologic tests and a simple chest radiograph showed no specific findings, but chest computed tomography revealed a centrilobular ground-glass pattern in both lung fields. A transbronchial biopsy was performed, and bronchoalveolar washing fluid was obtained. Among the findings of the laboratory tests, microcalcification, noncaseating granuloma containing foreign body-type giant cells, and metal particles within macrophages were identified histologically. Based on these results, hypersensitivity pneumonitis was diagnosed. The patient stopped working due to admission, and she completely quit her job within 2 months of restarting work due to reappearance of the symptoms.

In this study, the patient did not have typical radiologic findings, but pathological evaluation of the lung biopsy from the bronchoscope led to the suspicion of pneumonitis. Under the microscope, the sample contained fibrotic changes in the lung, multinucleated giant cells, and particles in macrophages and was diagnosed as dental technician pneumoconiosis by the pathology. Working as a dental technician had directly exposed her to light metal dust and MMA, and her clinical symptoms and radiologic findings subsided after withdrawal from exposure to the workplace. These outcomes led to the diagnosis of hypersensitity pneumonitis due to MMA exposure and strong work-relatedness.