Prognathism – Treatment Without Surgery, Causes, Skull, Radiology

Key Facts

• Prognathism refers to a positional discrepancy of the maxillary (upper) or mandibular (lower) jaw in relation to the facial skeleton and soft tissues
• There are mainly two types of prognathism: Maxillary prognathism where the upper jaw protrudes, and Mandibular prognathism where the lower jaw protrudes
• It can be caused by genetic factors, hormonal imbalances, or as a result of other conditions like acromegaly
• The treatment ranges from orthodontic braces to corrective jaw surgery, depending on the severity and underlying cause

What is Prognathism in Upper Jaw and Lower Jaw?

Prognathism (also called Habsburg chin, Habsburg’s chin, Habsburg jaw or Habsburg’s jaw) is a dental condition where there is an abnormal protrusion of either the upper jaw (maxilla) or the lower jaw (mandible), leading to an atypical facial appearance and malocclusion, which means misaligned teeth when the jaws are closed.
In maxillary prognathism, the upper jaw protrudes forward compared to the lower jaw. In contrast, mandibular prognathism, often referred to as an underbite, involves the lower jaw protruding beyond the upper jaw.
This condition can affect an individual’s ability to chew and speak, and may also have psychological and social impacts due to the alteration in facial appearance.

What Does Maxillary and Mandibular Prognathism Look Like?

Prognathism is characterized by a noticeable protrusion of the upper or lower jaw which alters the profile of the face (creates abnormal facial characteristics). There are two types of prognathism:

• Maxillary Prognathism: In cases of maxillary prognathism, there is a pronounced bulging of the upper jaw. This may cause the upper teeth to be prominently visible even when the mouth is closed, and the person might have a gummy smile.
• Mandibular Prognathism: With mandibular prognathism, the lower jaw and teeth noticeably jut out in front of the upper jaw. This gives the chin and lower face a pronounced appearance, often referred to as an underbite.

In both cases, the alignment of the teeth is often affected, and there may be gaps or crowding.

Who Does Prognathism Affect?

Prognathism can affect individuals of any age, gender, or race.
However, several factors can influence its occurrence:

• Genetics: A family history of prognathism can increase the likelihood of an individual developing the condition. Certain genetic disorders, such as Crouzon syndrome, can also be associated with prognathism.
• Hormonal Factors: Conditions such as acromegaly, where there is excess growth hormone, can cause prognathism. This usually affects adults.
• Environmental Factors: Habits like thumb-sucking or tongue-thrusting in childhood can affect the development of the jaw and lead to prognathism.
• Ethnicity: Certain racial backgrounds have a higher incidence of prognathism. For example, mandibular prognathism is relatively more common in individuals of Asian descent.

Understanding prognathism is essential for recognizing its impact on dental health and quality of life. In the subsequent sections, we will explore the causes in detail, methods of diagnosis, treatment options, and ways to manage and live with prognathism.

How Common is Prognathism?

The prevalence of prognathism varies depending on the population and the type of prognathism being considered. Mandibular prognathism is relatively more common, affecting around 1% of the general population. However, this figure can vary depending on ethnic background, with some studies showing higher rates among certain Asian populations. Maxillary prognathism is less common, and its prevalence is not as well documented. Prognathism can be both a congenital condition (present at birth) or develop later in life due to other factors such as hormonal imbalances or growth abnormalities.

Health Impacts of Prognathism: How Does Prognathism Affect My Health?

Prognathism can have several impacts on your health:

• Dental Issues: The misalignment of jaws can lead to improper fitting of the upper and lower teeth (malocclusion), which can cause wear and tear on the teeth, increase the risk of tooth decay, and contribute to the development of gum disease.
• Chewing and Speech: Prognathism can affect the ability to chew food properly and may contribute to speech issues such as a lisp or difficulty pronouncing certain words.
• Breathing Problems: In severe cases, particularly with maxillary prognathism, there may be issues with breathing through the mouth or nose, and it may contribute to sleep apnea.
• Facial Pain and TMJ Disorders: The abnormal positioning of the jaw can put stress on the muscles and joints, leading to facial pain and temporomandibular joint (TMJ) disorders.
• Psychological Impact: The altered facial appearance due to prognathism can have psychological impacts, including reduced self-esteem and social anxiety.

Facial Features Associated with Prognathism

Prognathism, characterized by the protrusion of the upper or lower jaw, can lead to various distinctive facial features, depending on which part of the jaw is affected and the severity of the condition. Here are some common facial characteristics associated with prognathism:

• Extended Chin: In mandibular prognathism, where the lower jaw protrudes, there is often a noticeable extension of the chin beyond the upper jaw.
• Protruding Jaw: Either the upper or lower jaw (or both in bimaxillary prognathism) juts out, altering the normal profile of the face.
• Altered Bite and Dental Structure: Misalignment of the teeth (malocclusion) is common, leading to an overbite or underbite, depending on the type of prognathism.
• Facial Asymmetry: In some cases, the condition can cause an asymmetrical appearance of the face.
• Broad Nose: Especially in maxillary prognathism, the mid-face may appear more prominent, sometimes including a broader nasal structure.
• Small Upper Jaw: In cases of mandibular prognathism, the upper jaw may appear relatively smaller or receded.
• Abnormal Facial Contours: The overall structure and contours of the face may appear irregular, with certain features being more pronounced.

Prognathism in Relation to Other Conditions

Prognathism can be associated with or indicative of various other conditions, either genetic or acquired:

• Basal Cell Nevus Syndrome (Gorlin Syndrome): This genetic condition can feature prognathism, among other symptoms like basal cell carcinomas and skeletal anomalies.
• Acromegaly: Caused by excessive production of growth hormone, often leading to an enlarged mandible and resultant prognathic jaw.
• Genetic Disorders: Conditions like Crouzon syndrome, Marfan syndrome, and Down syndrome can include prognathism as a characteristic feature.
• Environmental Influences: Childhood habits like thumb-sucking or prolonged use of a pacifier can influence jaw development and lead to prognathism.
• Developmental Abnormalities: Premature fusion of skull bones or abnormal bone growth can result in prognathism.
• Hormonal Imbalances: Disorders that affect hormone levels, especially during the growth phases of childhood and adolescence, can lead to abnormal jaw development.
• Trauma or Injury: Injuries to the jaw during developmental years can affect the growth and shape of the jaw, potentially causing prognathism.

What are the Symptoms of Prognathism?

The symptoms of prognathism can vary depending on whether it is maxillary or mandibular, and the severity of the condition:

• Visible Protrusion of the Jaw: The most obvious symptom is a noticeable protrusion of either the upper or lower jaw.
• Malocclusion: The upper and lower teeth do not align properly when the mouth is closed. This may cause difficulty in biting or chewing food.
• Altered Facial Appearance: Depending on which jaw is affected, the face may have an elongated appearance (maxillary) or a prominent lower face and chin (mandibular).
• Speech Problems: Pronunciation of certain sounds or words may be difficult.
• Mouth Breathing: There may be a tendency to breathe through the mouth rather than the nose, especially during sleep.
• Pain or Discomfort: There may be pain or discomfort in the jaw, particularly when chewing or speaking for extended periods.
• Gum Problems: The misaligned teeth can make it difficult to clean the teeth and gums properly, leading to an increased risk of gum disease.

Identifying the symptoms of prognathism early on is crucial in managing the condition effectively and preventing long-term health issues.

What Causes Prognathism?

Prognathism can be caused by a variety of factors, including:

• Genetic Factors: A family history of prognathism can be a significant factor. Certain genetic disorders such as acromegaly, Marfan syndrome, or Crouzon syndrome are known to cause prognathism.
• Hormonal Imbalances: Conditions like acromegaly, where there is an overproduction of growth hormone, can lead to the excessive growth of the jawbones.
• Environmental Factors: Habits such as thumb sucking or tongue thrusting in childhood can affect the growth and development of the jaws.
• Trauma or Injury: Injury to the jaw, especially during the growth phase, can lead to abnormal growth and development of the jawbones.
• Tumors or Cysts: Abnormal growths in the jaw area can push the jaw out of its normal alignment.

How is Prognathism Diagnosed?

Diagnosis of prognathism involves a series of steps:

• Medical History: The healthcare provider will begin by taking a detailed medical history, including any family history of prognathism or related disorders.
• Physical Examination: This includes a visual examination of the face and jaw, and an assessment of the bite to see how the teeth align. The healthcare provider may also ask the patient to open and close their mouth to observe jaw movement.
• Imaging Tests: X-rays, CT scans, or MRI scans may be used to get detailed images of the jawbones and surrounding structures. This helps in assessing the extent of the prognathism and planning treatment.
• Dental Models: Impressions of the teeth may be taken to create plaster models. These models help in analyzing the teeth alignment and bite.
• Referral to Specialists: If needed, referral to an orthodontist, oral surgeon, or a geneticist may be necessary for further evaluation.

How is Prognathism Treated? What is Corrective Jaw Surgery?

Treatment for prognathism depends on the severity of the condition, the underlying cause, and the age of the patient.

• Orthodontics: Braces and other orthodontic devices can be used to correct mild to moderate cases of prognathism by realigning the teeth and jaws. This is often a long-term treatment that may take several years.
• Orthognathic Surgery: In more severe cases, surgery to reposition the jawbones may be necessary. This is often done in conjunction with orthodontic treatment.
• Growth Modification: In children and adolescents, devices such as headgear or chin caps may be used to guide the growth of the jaws and prevent the development of prognathism.
• Therapy for Underlying Conditions: If prognathism is caused by a hormonal imbalance or another underlying condition, treating that condition is crucial.
• Physical Therapy: After surgery, physical therapy may be recommended to help regain normal jaw movement and alleviate discomfort.
• Psychological Support: Counseling or support groups can help patients cope with the emotional impact of changes in appearance due to prognathism.

It’s important for patients with prognathism to work closely with their healthcare providers to develop a treatment plan tailored to their specific needs.

Can You Fix Prognathism Without Surgery?

Yes, it is possible to address certain cases of prognathism without surgery, particularly when detected early. However, the feasibility of non-surgical treatment depends on the severity of the condition, the age of the patient, and the underlying cause. Here are some non-surgical options:

• Orthodontic Treatment: This involves using braces and other dental appliances to correct the alignment of teeth and modify the growth of the jaw. This option is more effective in children and adolescents whose jaws are still developing.
• Dental Appliances: For mild cases, dental appliances such as retainers or headgear can be used to alter the growth pattern of the jaw and guide it into the proper position.
• Behavioral Changes: Addressing habits like thumb-sucking or tongue thrusting early on can prevent the development or worsening of prognathism.
• Hormonal Therapy: In cases where prognathism is caused by hormonal imbalances, such as acromegaly, medication to control hormone levels may indirectly affect jaw growth.

It’s essential to note that in severe cases or when prognathism is due to structural abnormalities in the jaw bones, surgery might be the only effective treatment option.

How Long Does It Take to Recover From Orthognathic Surgery?

Recovery from orthognathic surgery can vary based on the complexity of the procedure, the patient’s health, and other factors.
Here is a general timeline:

• Immediate Recovery: The first 1-2 weeks after surgery often involve managing pain, swelling, and a liquid diet. Patients typically take 1-3 weeks off work or school during this time.
• Intermediate Recovery: Over the next 3-8 weeks, patients gradually return to a more normal diet and resume regular activities. There may still be some swelling and minor discomfort.
• Long-Term Recovery: It can take several months for the bones to fully heal and for the patient to adapt to the new jaw alignment. The final bite alignment is usually achieved through continued orthodontic treatment.

What Are the Risks of Orthognathic Surgery?

As with any surgery, orthognathic surgery comes with risks and potential complications, including:

• Infection: There is a risk of infection post-surgery, which can usually be managed with antibiotics.
• Bleeding: Some amount of bleeding is common, but excessive bleeding can be a complication.
• Nerve Damage: There is a risk of damage to nerves in the face, which can cause numbness or tingling.
• Relapse: In some cases, the jaw may shift back towards its original position after surgery.
• Speech or Eating Difficulties: Adjustments to the jaw can affect the way a patient speaks or eats.
• Aesthetic Changes: The shape of the face might change, sometimes in ways that the patient did not anticipate.
• Psychological Impact: The change in facial appearance can have psychological impacts, and counseling may be beneficial.

It’s important for patients to discuss the risks and benefits of orthognathic surgery with their healthcare provider to make an informed decision about whether this treatment is the right option for them. Regular follow-up appointments and adherence to post-operative care instructions are crucial for minimizing risks and ensuring a successful recovery.

Can I Prevent Prognathism?

The prevention of prognathism largely depends on the underlying cause. Some forms of prognathism are hereditary, and in such cases, there’s little that can be done to prevent the condition.
However, there are certain steps that can be taken to address or mitigate other causes:

• Early Intervention: In children, early orthodontic evaluation and intervention can sometimes prevent or lessen the severity of prognathism by guiding jaw growth.
• Addressing Habits: Certain habits, such as thumb sucking or mouth breathing, can contribute to the development of prognathism. Addressing these habits early in childhood can help in prevention.
• Managing Underlying Conditions: Prognathism can be secondary to other medical conditions, such as hormonal disorders. Proper management of these conditions can help prevent or control prognathism.

What Can I Expect If I Have Prognathism?

If you have prognathism, the following are some of the things you might expect:

• Dental Problems: Issues like difficulty in biting, chewing, and speaking, as well as abnormal tooth wear and jaw pain, are common.
• Facial Appearance: There may be noticeable changes in the profile and appearance of your face.
• Treatment Needs: Treatment for prognathism can range from orthodontic braces to surgery. This often requires a long-term commitment to the treatment plan.
• Psychological Impact: Having prognathism can have psychological effects such as low self-esteem or social anxiety, especially if it significantly affects facial appearance.

Basal Cell Nevus Syndrome and Prognathism

Basal Cell Nevus Syndrome, also known as Gorlin syndrome, is a rare genetic condition characterized by a range of abnormalities, including the development of numerous basal cell carcinomas (skin cancers), jaw cysts, and skeletal anomalies. One of the distinctive facial features associated with Basal Cell Nevus Syndrome is prognathism, which refers to the protrusion or forward positioning of the jaw, particularly the mandible (lower jaw).
Prognathism in the context of Basal Cell Nevus Syndrome is often a part of a broader spectrum of craniofacial abnormalities. These can include a broadened head, cleft lip or palate, and other irregularities in facial bone development. The prognathism may become more noticeable with age and can contribute to a characteristic facial appearance for individuals with this syndrome.

When Should I See My Healthcare Provider?

You should consider seeing a healthcare provider or dentist:

• Early Signs: If you notice that your lower jaw is protruding or if your child has signs of prognathism, it’s good to seek evaluation early.
• Dental Issues: If you’re experiencing difficulties in biting, chewing, speech issues, or jaw pain.
• Facial Concerns: If you have concerns about the appearance of your face or jaw, especially if it’s affecting your self-esteem or causing distress.
• Underlying Medical Conditions: If you have a medical condition that can cause prognathism, such as a hormonal disorder.

Bottom Line

Prognathism is a condition where the lower jaw protrudes beyond the upper jaw. While some cases of prognathism are due to genetic factors and cannot be prevented, early intervention and addressing certain habits can play a role in preventing or mitigating the condition. Prognathism can have physical and psychological impacts, and it’s important to seek professional advice and intervention if you notice signs of this condition. Treatment can range from orthodontic appliances to surgery and often involves a long-term commitment. It is vital to communicate openly with healthcare providers to understand the options and develop a tailored treatment plan.

This article is complete and was published on July 11, 2023, and last updated on December 7, 2023.