It usually takes four years of dental school, and after you've completed your bachelor's degree, to earn your Doctor of Dental Surgery (DDS) or Doctor of Dental Medicine (DMD). If you wish to work in a particular specialty, it will require additional post-graduate work. The Commission on Dental Accreditation (CODA) of the American Dental Association recognizes nine separate dental specialties:
Dental Public Health involves the prevention and control of dental diseases and promoting dental health within a community, rather than on an individual basis as is the case in private practice.
Endodontics involves studying, treating and preventing diseases of the dental pulp.
Oral and Maxillofacial Pathology deals with diseases that affect the oral and maxillofacial (jaw) regions.
Oral and Maxillofacial Radiology involves the interpretation of radiologic images used to diagnose and management of oral and maxillofacial diseases.
Oral and Maxillofacial Surgery involves the surgical treatment of oral and maxillofacial diseases (extractions, implants, etc.).
Orthodontics and Dentofacial Orthopedics involves the correction of malocclusion (straightening teeth), as well as any abnormalities of the jaw area.
Pediatric Dentistry involves providing oral health care for infants and children.
Periodontics involves the study and treatment of diseases of the surrounding and supporting tissues of the teeth, and involves placing and maintaining of dental implants.
Prosthodontics involves treating patients who have missing or defective teeth by use of prosthetic devices such as dentures and bridges.
As you can see there are many specialties to choose from in dentistry, the choice is yours. You may also become a dental assistant or a dental hygienist. These are some of the choices if you want to study for two to four years. An associate degree is sufficient for practicing in private dental offices, while a bachelor's or master's degree can lead to careers in research, administration, teaching or clinical practice in public or school health programs.