That is for a specific type of dental surgery. Also the failure does not mean the patient dies. It means allergic reactions, second operation requires, fracture

That is for a specific type of dental surgery. Also the failure does not mean the patient dies. It means allergic reactions, second operation requires, fractured tooth etc. To give you an example in some cases the bone is so weak that they have to use a Cow's bone marrow to fill it. In some people the body rejects this and hence another surgery is required where a person's hip bone marrow is used.