Also known as: Extended chin
- You have difficulty talking, biting, or chewing related to the abnormal jaw alignment.
- You have concerns about jaw alignment.
- Is there any family history of an unusual jaw shape?
- Is there difficulty talking, biting, or chewing?
- What other symptoms do you have?
Prognathism is an extension or bulging out (protrusion) of the lower jaw (mandible). It occurs when the teeth are not properly aligned due to the shape of the face bones.
Prognathism may cause malocclusion (misalignment of the biting surfaces of the upper and lower teeth). It can give a person an angry, or fighter's appearance. Prognathism may be a symptom of other syndromes or conditions.
An extended (protruding) jaw can be part of a person's normal face shape that is present at birth.
It can also be caused by inherited conditions, such as Crouzon syndrome or basal cell nevus syndrome.
When to Contact a Medical Professional
A dentist or orthodontist may be able to treat abnormal alignment of the jaw and teeth. Your primary health care provider should also be involved to check for underlying medical disorders that can be associated with prognathism.
Call a provider if:
What to Expect at Your Office Visit
The provider will perform a physical exam and ask questions regarding your medical history. Questions may include:
Diagnostic tests may include:
This condition may be treated with surgery. An oral surgeon, plastic facial surgeon, or ENT specialist may perform this surgery.
Taub DI, Jacobs JMS, Jacobs JS. Anthropometry, cephalometry, and orthognathic surgery. In: Neligan PC, ed. Plastic Surgery. 3rd ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 16.
Whyte MP. Hereditary disorders of the skeleton. In: Jameson JL, De Groot LJ, de Kretser DM, Giudice LC, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 68.
- Review date:
- December 07, 2016
- Reviewed by:
- Michael Kapner, DDS, general and aesthetic dentistry, Norwalk Medical Center, Norwalk, CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2008 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.