An underbite, or mandibular prognathism is an orthodontic condition in which the lower jaw protrudes beyond the upper jaw. In children with a normal jaw relationship, the lower jaw should be slightly behind the upper jaw resulting in the upper front teeth being ahead of and overlapping the lower front teeth. When a patient has an underbite, the excessive growth of the lower jaw causes the lower front teeth to protrude ahead of and overlap the top front teeth.
While underbites are far less common than overbites, they do effect around 1 in 10 Canadians. When Dr. Virdee first assesses a patient for treatment of an underbite in Sudbury, she evaluates several components including, a patient’s medical and family histories, their growth, as well as their face and teeth using a clinical exam and x-rays. Here are 10 facts that you need to know about underbites:
Underbites have a large genetic component. This means that you are born with an underbite and inherit from your parents. When you come in for a consultation with us, the first question that Dr. Virdee will ask is whether there is a family history of an underbite. Even if a grandfather, aunt or distant cousin have the same condition, this information can be significant information for diagnosis as well as treatment. As an example, the underbite, or the Habsburg Jaw manifested itself everywhere in Medieval Europe because of generations of royals marrying each other. In fact, this physical feature because especially pronounced in Spanish Habsburgs because of inbreeding. King Juan Carlos I, the current ruler of Spain, is a distant descendant of the House of Habsburg although he does represent Philip V’s House of Bourbon. He does have the Habsburg Jaw, but in a much more diminished capacity.
People from different ethnic groups are at higher risk for developing underbites. For example, people of Asian descent (Chinese, Korean, Japanese etc) have a higher propensity for mandibular prognathism or underbites. In Northern Ontario, including Sudbury, Sturgeon Falls, North Bay, Massey where there is a larger population of First Nations communities, there is a higher percentage of patients with underbites.
3. Birth Defects
Congenital abnormalities or birth defects such as cleft lip and palate and Cruzon’s syndrome are more likely to have an underbite. These patients need special consideration as they must be treated by a team of professionals, including the orthodontist. Dr. Virdee works with special medical organizations around the world to help patients with cleft lip and palate. You can read about it here.
4. Growth Potential
Growth or the potential for growth is very important when assessing how to treat a patient with an underbite. A young patient presenting with an underbite still has a huge potential for growth, especially when they go through their final growth spurt during puberty when the lower jaw tends to have a higher growth velocity. The treatment alternatives for the correction of an underbite are greater in younger patients because we can take advantage of their growth so that we can avoid extractions or surgery later in life. Therefore, the best way to treat an underbite is to treat it early with an appliance called a protraction face mask or face mask.
5. Limited or No Growth Potential
By comparison, adult patients who have limited or no growth potential will not have any options for treatment of their underbites using growth modification because we cannot take advantage of their growth. As a result, depending on the severity of the underbite the options are likely to be surgery, extraction of permanent teeth, or reducing the size of the teeth by trimming the sides of the teeth, a procedure called inter proximal reduction or IPR.
6. The Face
In adults with an underbite, the treatment options are dependent on their facial appearance. Dr. Virdee will assess the extent of the mandibular prognathism or the extent of lower jaw growth in comparison the the upper jaw by assessing the facial appearance. If the facial appearance looks normal, then the underbite is likely to be corrected with braces or Invisalign, without surgery. In this case extractions or reducing the size of the teeth by trimming them with IPR may be required. If the lower jaw is prominent or prognathic and the patient’s facial appearance or profile is of concern, surgery is likely to be recommended.
7. The Cephalometric X-ray
The cephalometric x-ray is used to evaluate growth and assess the size and position of the jaws. It also allows us to further evaluate if an underbite can be treated with or without surgery.
8. The Teeth
Both in adult and children, it is very important to assess the teeth to evaluate the cause of the underbite. Some patients may be missing teeth in the upper jaw or will have severe crowding in the upper jaw, which will result in an underbite. Some patients may have extra teeth or spacing in the lower jaw, which will also result in an underbite. Assessment of the teeth is very important to determine the course of action or treatment that Dr. Virdee may institute for correction of the underbite. The crowding, spacing and position of the teeth will also determine if we use Invisalign or braces.
9. The Shift
In assessing the teeth and the bite, Dr. Virdee will also assess whats called a CR-CO shift. This shift is usually present when there is some interference between the upper and lower front teeth, resulting in a shift of the lower jaw forward. Dr. Virdee will usually assess this during the initial evaluation where the lower jaw is brought into CR, the relaxed position of the lower jaw. In this position, if there is contact between the front teeth but not the back teeth, the front teeth, upper or lower may be in interference which results in a forward shift of the lower jaw to CO where the back teeth are in contact but an underbite exists. Shifts can be corrected by either braces, Invisalign or selective grinding of the upper or lower teeth. Which option is best will be determined by Dr. Virdee’s assessment.
10. Complications of the Underbite
Several complications may arise with having an underbite. In extreme cases, underbites cad cause facial abnormalities such as a prominent lore jaw and chin. Underbites can cause difficulty chewing, swallowing, and speaking and sometimes low self esteem because of the patient’s facial abnormalities. The bite problems can wear down a tooth’s enamel increasing a patient’s chances for tooth decay and other oral health issues.
To find out if your child is suffering from an underbite visit our office today for a complimentary evaluation with Dr. Virdee at Hometown Orthodontics.
Got any questions that you want answered on our blog? Whether you are in Sudbury, North Bay, Sturgeon Falls, Massey or Espanola, contact Dr. Virdee at firstname.lastname@example.org.