BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuPrognathismExtended chin; UnderbitePrognathism 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. Considerations 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. Causes 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.Basal cell nevus syndromeNevoid basal cell carcinoma syndrome is a group of defects passed down through families. The disorder involves the skin, nervous system, eyes, endoc...ImageRead Article Now Book Mark Article It may develop over time in children or adults as the result of excess growth in conditions such as gigantism or acromegaly.GigantismGigantism is abnormal growth due to an excess of growth hormone (GH) during childhood.ImageRead Article Now Book Mark Article AcromegalyAcromegaly is a condition in which there is too much growth hormone (GH) in the body.ImageRead Article Now Book Mark Article 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.Contact a provider if:You or your child have difficulty talking, biting, or chewing related to the abnormal jaw alignment. You have concerns about jaw alignment. What to Expect at Your Office Visit The provider will perform a physical exam and ask questions regarding your medical history. Questions may include:Physical examDuring a physical examination, a health care provider studies your body to determine if you do or do not have a physical problem. A physical examinat...Read Article Now Book Mark Article Is there any family history of an unusual jaw shape? Is there difficulty talking, biting, or chewing? What other symptoms do you have? Diagnostic tests may include:Skull x-ray (panoramic and cephalometric) Skull x-rayA skull x-ray is a picture of the bones surrounding the brain, including the facial bones, the nose, and the sinuses.ImageRead Article Now Book Mark Article Dental x-rays Dental x-raysDental x-rays are a type of image of the teeth and mouth. X-rays are a form of high energy electromagnetic radiation. The x-rays penetrate the body...Read Article Now Book Mark Article Imprints of the bite (a plaster mold is made of the teeth) This condition may be treated with surgery. An oral surgeon, plastic facial surgeon, or ENT specialist may perform this surgery. Open ReferencesReferencesDhar V. Malocclusion. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 335.Goldstein JA, Baker SB. Cleft and craniofacial orthognathic surgery. In: Rodriguez ED, Losee JE, Neligan PC, eds. Plastic Surgery: Volume 3: Craniofacial, Head and Neck Surgery and Pediatric Plastic Surgery. 4th ed. Philadelphia, PA: Elsevier; 2018:chap 28.Koroluk LD. Adolescent patients. In: Stefanac SJ, Nesbit SP, eds. Diagnosis and Treatment Planning in Dentistry. 3rd ed. St Louis, MO: Elsevier; 2017:chap 16.AllVideoImagesTogPrognathism - illustration Prognathism is a descriptive term for a jaw (upper or lower) that protrudes forward beyond the plane of the face.PrognathismillustrationMalocclusion of teeth - illustration Occlusion refers to the alignment of teeth and the way that the upper and lower teeth fit together (bite). Malocclusion is the most common reason for referral to an orthodontist. Most malocclusion is mild enough not to require treatment. If a severe misalignment is present, orthodontics and/or oral surgery may be required.Malocclusion of teethillustrationPrognathism - illustration Prognathism is a descriptive term for a jaw (upper or lower) that protrudes forward beyond the plane of the face.PrognathismillustrationMalocclusion of teeth - illustration Occlusion refers to the alignment of teeth and the way that the upper and lower teeth fit together (bite). Malocclusion is the most common reason for referral to an orthodontist. Most malocclusion is mild enough not to require treatment. If a severe misalignment is present, orthodontics and/or oral surgery may be required.Malocclusion of teethillustrationRelated Information Review Date: 1/24/2022 Reviewed By: Michael Kapner, DDS, General Dentistry, Norwalk Medical Center, Norwalk CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. 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. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- © 1997- All rights reserved. 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