An open bite describes a condition where some of the upper and lower teeth do not make contact when the mouth is closed. This results in a visible gap between them. Skeletal open bite is a specific type of open bite where the underlying jaw structure contributes to this vertical separation of the teeth.
Understanding Skeletal Versus Dental Open Bite
An open bite can stem from tooth positioning or jawbone structure. A dental open bite occurs when teeth fail to meet, but the jawbones themselves are generally in normal alignment. This type often arises from habits such as prolonged thumb-sucking or tongue thrusting, which can impede tooth eruption or push teeth out of alignment.
Skeletal open bite, however, stems from a disproportionate growth of the upper and lower jaws, leading to a vertical gap between the front teeth even when the back teeth are closed. This condition involves a vertical disharmony of the craniofacial skeleton, often characterized by an increased lower facial height compared to the upper facial height.
Factors Contributing to Skeletal Open Bite
Skeletal open bite development is often influenced by a combination of factors, with genetic predisposition playing a significant role. Family history and genetics can influence jaw growth patterns, leading to inherited tendencies for open bites, including the shape and alignment of jaws and tongue.
Abnormal growth patterns of the facial bones are another primary contributor. For instance, excessive vertical growth of the posterior part of the upper jaw (maxilla) or a short lower jaw (mandible) can prevent the front teeth from meeting properly when the mouth is closed. This can result in a “long face” appearance due to increased lower anterior facial height. Hyperdivergent facial growth patterns, where the maxillary, occlusal, and mandibular planes diverge excessively, are commonly associated with skeletal open bite.
Environmental and habitual factors can also contribute to or worsen an existing skeletal open bite, particularly during growth. Chronic mouth breathing, often due to nasal obstructions or allergies, can alter normal jaw development and dental structures. Atypical tongue posture, such as tongue thrusting where the tongue pushes against the teeth during swallowing or at rest, can also exacerbate the condition by preventing the vertical eruption of front teeth.
Recognizing and Diagnosing Skeletal Open Bite
Recognizing a skeletal open bite often begins with noticeable visible signs. Individuals may observe that their front upper and lower teeth do not touch when their mouth is closed, leaving a visible gap. This can lead to an elongated facial appearance or difficulty in completely closing the lips without strain.
Beyond aesthetics, functional issues are common. People with a skeletal open bite may experience difficulties biting into certain foods, especially those that require tearing or incising with the front teeth. Speech impediments, such as lisping or trouble pronouncing specific sounds, can also arise due to the improper alignment. Jaw discomfort or pain, particularly during eating or speaking, may also be present.
Professional diagnosis typically involves a comprehensive evaluation by a dentist or orthodontist. This includes a clinical examination to assess tooth alignment and jaw structure. Diagnostic tools such as dental impressions or digital scans are used to create models of the bite for detailed analysis and treatment planning. X-rays, particularly lateral cephalometric radiographs, provide detailed views of jaw structures, assess jaw angles, and evaluate growth patterns.
Corrective Treatment Options
Corrective treatment for skeletal open bite varies significantly based on the patient’s age and the severity of the condition. For children and adolescents whose jaws are still developing, early intervention, often termed growth modification, is a primary approach. This involves using functional appliances like palatal expanders, headgear, or chin cups to guide jaw growth and encourage proper alignment. These appliances aim to restrict excessive vertical growth of the upper jaw or promote more favorable growth of the lower jaw, thereby reducing the skeletal discrepancy.
Orthodontic treatment is employed for less severe cases or as part of a combined approach. Braces or clear aligners can effectively reposition teeth to improve bite closure. While orthodontics alone can address dental components of the open bite, their ability to correct significant underlying skeletal discrepancies is limited. However, they are often used in conjunction with other treatments to achieve optimal tooth positioning.
For severe skeletal open bites, especially in adults where jaw growth has ceased, orthognathic surgery, commonly known as jaw surgery, is often the recommended solution. This surgical procedure involves repositioning the jawbones to achieve proper alignment and bite closure. Such surgery is typically combined with orthodontic treatment, where braces or aligners are used before and after the surgical procedure to ensure teeth are correctly aligned with the newly positioned jaws. The goals of treatment generally include improving facial aesthetics, enhancing chewing function, and correcting speech impediments.