This is a very difficult scenario. If the allergy is caused by prolonged exposure in the workplace and the dentist has paid into Workers Compensation, the assistant may qualify under a WSIB (Workers Safety Insurance Board) claim. However, we know that approximately only 15% of dental officespay into WSIB, so chances are this may not be the case.If she is a long-term employee, the employer is required to come up with a solution. The Ontario Ministry of Labour may provide some assistance such as sending an inspector to the office to make recommendations or covering some of the associated costs.A last resort would be to resign, but before that happens, please ask her to call he ODAA office for some assistance.