Bionators are functional, removable appliances designed to correct overbites by promoting lower jaw growth. They can also be used to improve teeth positions in patients with an underdeveloped lower jaw. Bionators are suitable for patients aged seven years or older, with optimal results obtained while the patient is still growing.
Although the appliances are removable, they are meant to be worn most of the time. Ideally, they should only be removed for cleaning, eating, playing sports, or when there is a risk of dental injury. Bionators are useful for treating Class II malocclusions associated with an underdeveloped mandible. Their popularity lies in the ease of use for both the clinician and the patient. The design makes them easy to wear, providing a high level of patient compliance.
Timing is important when using functional jaw orthopedics, as studies have shown the therapeutic effectiveness of treatment is closely linked to the patient’s age. The Bionators will generally provide the greatest benefit when used during the ascending portion of the pubertal growth spurt. It is possible for significant skeletal effects to be achieved in the mandible, which can affect the soft tissues, changing the lip position and vertical dimensions of the face. In comparison, patients treated before this peak period will achieve more significant effects at the dentoalveolar level. Generally, these changes consist of retracting and positioning the maxillary incisors into a more upright position. Increases in mandibular molar eruptions are also possible.
Treatment using the Bionator I and the Bionator II is effective and stable, especially when initiated just before the pubertal growth spurt. For girls, this takes place between the ages of eight and thirteen; for boys it is between the ages of ten and fifteen.
Features of the Bionator I
The Bionator I is used to treat patients with a deep bite and Class II malocclusion, utilizing screws to lengthen and widen the upper and lower jaw while opening the bite. The appliance is designed to hold the mandible in a slightly-forward position using acrylic. Facially-angled grooves are created in the acrylic, helping to guide the eruption of the posterior teeth and correcting a deep bite. At the same time, it is expanding the dental arches.
While the anterior teeth are covered with an acrylic cap, the posterior teeth remain uncovered. The maxillary incisors contact the acrylic cap on a flat plane. This prevents the anterior teeth from erupting incorrectly and also prevents the lower incisors from flaring, an effect that may occur when forces are exerted on the lower jaw.
To allow the tongue to be correctly positioned, there is no acrylic in the palatal area. The two sides of the appliance are joined using an omega loop coffin spring which is fitted across the palate to increase rigidity. Screws can be activated to provide lateral expansion, while a screw may also be located on the lingual midline.
Features of the Bionator II
Although it is also used to treat patients with a Class II malocclusion, the Bionator II has a slightly different construction. The main difference is that this appliance is designed to help patients with an open bite. It helps to close the bite while repositioning the lower jaw. With this appliance, the posterior teeth are fully covered, preventing these teeth from erupting undesirably. Bionator II leaves the anterior teeth uncovered, which will allow them to erupt, eventually correcting the open bite.
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