What is the ruling on refusing to pay the costs of dental treatment to a dentist who promised the service for free then demanded a sum of money, especially after the treatment caused severe health damages to the patient?

This gift falls under the category of employee gifts, which are given to them due to their work, and it is not permissible to accept it except with the employer's permission. If the employer gives permission, the employee is not required to pay for the tooth extraction, because it was promised free of charge by the general manager, and a promise becomes binding if the promisee undertakes work based on it.

Regarding medical error, it should be examined whether it is a natural error or if the treating physician is ignorant of medicine and his error is inexcusable. If it is the latter, then he is liable.