Prosthodontics is one of the nine dental specialties recognized by the American Dental Association (ADA). A prosthodontist is a dentist who specializes in prosthodontics. Prosthodontic training requires an additional 3-4 years of training after obtaining a dental degree (D.D.S. or D.M.D.) in an ADA approved program. Prosthodontists specialize in the restoration of oral function by creating prostheses and restorations (i.e. Complete dentures, crowns, implant retained/supported restorations). Training consists of rigorous preparation in head and neck anatomy, materials science, esthetics, and occlusion (bite). Due to this extensive training, prosthodontist are frequently called upon to treat TMD related disorders, congenital disorders, and sleep disorders by planning and fabricating various prostheses and orthotic appliances. Maxillofacial prosthetics is a sub-specialty of prosthodontics requiring an additional year of training after completing an ADA approved prosthodontic training program. Maxillofacial prosthodontists treat patients who have acquired and congenital defects of the head and neck (maxillofacial) region due to surgery, trauma, and/or birth defect. Artificial eyes, ears, and maxillary obturators are commonly planned and fabricated by maxillofacial prosthodontists. Other less commonly employed prostheses include mouth devices used by amputees to aid in daily activities, and tracheostomy obturators.