A pediatrician is a doctor who specializes in the regular care of children, as well as the diagnosis and treatment of illness in children. Young patients are often more complicated to treat because they are still growing and developing.
While pediatricians may sub-specialize in specific therapy areas like oncology, surgery, ophthalmology, and anesthesiology, in general, pediatricians provide services like vaccinations, health exams, and treatment of common ailments and injuries. In addition, pediatricians are trained to handle the complex emotional and behavioral issues faced by children, especially during puberty.
Pediatricians normally see their patients from birth until the age of 18, although some may agree to treat patients into their early 20s, if requested.

A nephrologist is a physician who is specially trained to diagnose and treat conditions affecting the kidneys or renal system.
A nephrologist will determine through urine analysis, blood test, X-ray, sonogram, or kidney biopsy how well the kidneys are functioning and will then prescribe a special diet and exercise program, medication or dialysis - a process by which a machine filters the blood when the kidney is no longer capable of doing so.

A dentist is a doctor who diagnoses and treats oral health issues. The most basic services dentists provide are preventative and regular maintenance treatments such as cleanings, fluoride treatments, X-rays (to look for cavities), cavity fillings. He or she also provides advice on proper brushing, flossing, and rinsing for the prevention of plaque buildup.

An oral & maxillofacial surgeon is a physician who surgically corrects conditions of the mouth and surrounding facial structures including the head, neck and jaws. These doctors usually start out as dentists before undertaking extensive surgical and medical training.