Details of the distal bite and methods for its correction in children and adults

In simple terms, the distal bite is such malocclusionin which the teeth of the upper jaw are strongly advanced forward with respect to the teeth of the lower jaw. Well, as expressed in the language of orthodontists, a bite is considered distal, in which the first molars of the upper and lower jaw close in the second class of Engle, that is, the lower jaw reduced in size is behind the dominant upper jaw.

Generally speaking, such an arrangement of the jaws is not so rare, and occupies about 30 percent of the prevalence among the European population of the Earth.

Let's see, what, in fact, is the distal bite bad, what are the reasons for its appearance, and also whether it is necessary to deal with the prevention of the development of the distal bite and treatment, if it has already formed ...

 

Types of distal bite and problems created by it

First of all, it should be borne in mind that distal bites are, so to speak, different - respectively, and problems in people with such an anomaly also differ.

When diagnosing a distal occlusion, orthodontists distinguish two subclasses: the difference is due to the position of the front teeth, namely the incisors, and the inclination of the incisors often greatly affects the course of the pathology and treatment tactics of the patient.

So, for example, during the first subclass of the distal bite or, as it is also called, the horizontal type of the distal bite, the incisors of the lower jaw abut with their cutting edges on the palatal surfaces of the upper incisors, which, in turn, are inclined towards the upper lip.

In grade 2, subclass 2 or, in other words, the vertical type of the distal bite, the cutting edges of the lower incisors abut against the palatine tubercle of the upper incisors, while the upper central incisors are inclined towards the oral cavity. Sometimes the upper front teeth rest against the gum, resulting in trauma to it (traumatic bite).

The incline of the incisors affects not only the shape of the person’s face, which may eventually become far from normal, but also on the specific problems that often accompany the distal bite.

For example, the formation of an open bite in the anterior section (the first subclass of class II), that is, when the upper front teeth protrude forward, leads to impaired sound pronunciation, difficulty in eating, and also sometimes to problems with the gastrointestinal tract.

The photo below shows an example of an open bite:

In the second subclass of class II, the situation is the opposite: a deep bite is formed in the front section, that is, the front upper teeth sink into the interior. Patients note lisping, in some cases, children complain of an injury caused by the lower incisors in contact with the soft palate - such wounds do not heal for a very long time, since soft tissues are constantly injured when chewing.

Among other common problems accompanying the distal bite, patients note problems with the temporomandibular joint (TMJ): there are pains when opening the mouth, pains in chewing, headaches, crunching and clicking in the joint. These joint disorders occur due to improper position of the head of the lower jaw in the articular fossa, compression of the articular ligaments, and overstrain of the masticatory muscles. Over time, in the absence of proper treatment, symptoms can progress, forcing a person to resort to regular administration of painkillers.

Gingival recession and wedge-shaped defects are also frequent consequences of a distal bite: due to improper position of the jaws and teeth, an involuntary overload of the masticatory apparatus and compensatory loss of soft gum tissue occur. In turn, all this leads to tooth sensitivity when brushing, when taking cold, sour and solid foods.

In the photo - gum recession at the base of the lower teeth:

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An unpleasant consequence of the long presence of a distal bite, especially in childhood, is the development of psychological problems - in particular, low self-esteem: a child is shy of his appearance due to improperly standing teeth, is afraid to smile. In the absence of timely adequate treatment (correction of occlusion), such psychological problems can accompany a person in the future throughout his adult life.

In addition, over time, if the distal bite is not treated, complications such as premature abrasion of teeth, their pathological mobility and premature loss are sometimes observed.

 

How can a patient's face change due to a distal bite (facial features)

With the development of a distal bite, a person’s face usually undergoes appropriate changes, and not for the better. However, such changes are largely reversible: after treatment, the face profile in most cases returns to a state close to the physiological norm - in other words, the person begins to look more beautiful (this is clearly visible when comparing photographs before and after treatment of the distal bite).

So, that usually immediately gives a distal bite when looking at a person’s face:

• The concave profile is the so-called “bird's face”. This occurs due to the fact that the lower jaw is in the rear position relative to the upper, as a result of which a visible step is created between the upper lip and the base of the chin. The photo below shows an example of such a profile:
• Depending on the inclinations of the incisors, the upper lip with a distal bite can either be advanced forward when the lower lip is retarded and strained, or the upper lip may be stuck with the lower lip slightly extended forward. The second option is to compensate for an open bite in the anterior part of the dentition, when the patient, in the presence of a sagittal fissure (the space between the teeth of the upper and lower jaw), is forced to strain his lower lip to close his mouth;
• A characteristic sign of the distal bite can also be a pronounced intense chin fold - with an average and large sagittal fissure (3-6 mm or more), the chin fold is constantly in tension with the patient's mouth closed.

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Sometimes, for a complete understanding of the clinical picture and construction of treatment tactics, the orthodontist may conduct specific clinical tests, for example, the Ashler-Bitner test, which allows you to determine which of the jaws is “to blame” for the abnormal bite.

To conduct the test, the doctor remembers or photographs the patient’s profile at rest, and then asks to push the lower jaw forward to the physiological position of the first molars. If the profile of the face improves, the cause of the formation of the distal bite is underdevelopment and improper position of the lower jaw, and if the profile worsens, then the deficit of the growth of the upper jaw causes a problem. If the profile of the face first improves and then worsens, then the distal bite is caused by a growth imbalance in both jaws.

 

Reasons for the formation of pathology

Let's see why a distal bite occurs at all - what causes the position of the jaws along with the dentition to begin to deviate from the norm.

• Endogenous diseases carried by a child in early childhood can lead to the development of a distal bite. For example, rickets causes changes in the bone structures of the whole organism, greatly influencing the process of their development. So, the lower jaw in children who have undergone rickets is usually reduced in size, compared with the norm. The picture shows the so-called rickets bite (open);
• Diseases of the nasopharynx, enlargement of the pharyngeal tonsils, frequent colds, curvature of the nasal septum - all this makes the child breathe through his mouth, which, in turn, has a direct effect on the formed occlusion. Due to frequent oral breathing, the upper and lower jaw are displaced in the anteroposterior direction, the tongue sinks to the bottom of the oral cavity, creating an open bite in the anterior part and a distal bite in the lateral area of ​​the dentition;
• Injuries to the maxillofacial region: falls, strong blows to the face of the child during the period of active growth can slow down or even disrupt the development of the jaw bones, especially the lower jaw. Since the bone tissue in children is still quite soft, even a minor blow from the point of view of an adult can cause the lower jaw to move to its posterior position and reduce its relative size in the near future with the formation of a distal bite;
• Bad habits - propping up a chin with a fist, sucking a finger, pencils and other foreign objects. If this is an everyday involuntary repeating process, then it becomes a kind of orthodontic force directed "in the wrong direction." In particular, this causes the lower jaw to gradually move backward under the influence of pressure, while, among other things, an open bite is formed: the front teeth of the upper and lower jaw lean towards the lips, a sagittal fissure appears;
• We must not forget about the factor of heredity - the bite, like other phenotypic features (eye color, hair color), is inherited by the child from parents. Sometimes the mismatch in the size of the jaws is due to the fact that one jaw developed like a father’s, and the other - like a mother’s child;
• Extraction of teeth in childhood due to caries and its complications provokes the displacement of adjacent teeth towards the removed, because nature does not tolerate emptiness. Thus, sometimes whole groups of teeth are displaced to replace the appeared space. To avoid this phenomenon (and if you still need to remove the tooth), the pediatric dentist sends the child to the orthodontist to manufacture a special apparatus that saves space for further eruption of permanent teeth in place;
• Late weaning from the nipple can also cause a distal bite. The sucking reflex in infancy contributes to the growth and development of the lower jaw, but if the sucking nipple lasts more than 1-1.5 years, then it already begins to cause harm. The lower jaw while sucking the nipples shifts back, under the action of the lips and tongue, the front teeth of the upper jaw lean forward, forming an open bite;
• The presence of exceptionally soft food in the child’s diet leads to a decrease in the size of the jaws, because the child’s dentition does not experience the proper load, which is necessary to stimulate the growth and development of the jaw bones. As a result, there is a narrowing and flattening of the jaws, especially the lower jaw.

 

Principles for the treatment of distal occlusion in children

A very effective way to treat a distal bite in children is myogymnastics - provided that the child regularly performs exercises.

The first exercise with myogymnastics: you need to push the lower jaw forward so that the lower incisors overlap the upper ones. In this position, you need to hold the jaw for a few seconds. Exercise is performed until the muscles are tired.

The second exercise: raise the tongue to contact with the palatine surfaces of the upper teeth.

In combination with the use of special removable devices, the treatment of a distal bite can be greatly reduced in terms of time, and the achieved result will be as stable as possible. For example, in an early removable bite (milk), removable devices with a screw are used to expand and control the growth of both jaws. An example of such an apparatus is shown in the photo below:

The doctor may also suggest that the child wear a silicone double-jaw splint that relaxes the muscles and pushes the lower jaw to the correct forward position. Such devices include trainers, LM activators.

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Removable orthodontic appliances are effective both in the milk bite and during the change of teeth. For example, with a distal bite in a 10-year-old child, the use of trainers, correctors, and other silicone tires can serve as a preparation for the stage of active orthodontic treatment for the bracket system, thereby reducing the period of wearing braces.

Removable devices are capable of exerting the required therapeutic effect only with strict observance of the wearing regimen prescribed by the doctor. So, for example, the wearing mode of silicone devices is usually 2 hours during the day and all night.

In the relatively “adult” age of the child (8-10 years), orthodontists use devices such as Twin block - this is a system consisting of two plates, which, forming a block between themselves, push the lower jaw forward.

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For the manufacture of apparatus with paired blocks, in addition to taking casts, the stage of determining a structural bite is important. To do this, the doctor asks the patient to push the lower jaw forward until the first class condition is achieved in molars. The orthodontist fixes this position using wax bite patterns, or using silicone material. Then these templates together with the models are sent to the laboratory for the manufacture of the apparatus.

Sometimes the orthodontist prefers to partially fix the braces on the already erupted permanent teeth: the bracket system allows you to align the dentition and put the teeth in the correct position. On the bracket system, it is more convenient to move the 6th and 7th teeth with the help of the springs to the rear position - distalize them to Angle class I position (to the norm).

In children and adults at the final stages of treatment of the distal bite, if the correct position of the lower jaw has not been reached, the orthodontist may suggest wearing the Herbst apparatus and its modifications. This apparatus consists of two spring modules: the upper part of the module is fixed to the 6th teeth of the upper jaw, and the lower part is fixed either to the canine or to the premolar of the lower jaw. The springs push the lower jaw forward, while the upper jaw moves slightly to the rear position.

 

Treatment for distal occlusion in adults

In adults, depending on the severity of the pathology, several stages of orthodontic treatment of the distal bite can be distinguished. The first stage is preparation for fixing active equipment (bracket system). To reduce the time of treatment for braces, as well as to ultimately achieve a stable and expected result, orthodontists begin treatment with the fixation of various frame devices.

For example, Distal Jet is quite popular today:

Such an orthodontic apparatus allows you to move the first molars of the upper jaw to the back position, until the ratio of the molars in the first Angle class, that is, to the norm, is reached.

Structural elements include:

• Rings pre-arranged by the doctor for molars and premolars;
• Palatine arch - arc elements that go from rings on premolars to the center of the crown of fangs. Thus, stabilization of the anterior segment of the upper jaw is created and the possible extension of the anterior teeth is prevented;
• The Nanase button is a lamellar element of the base adjacent to the middle of the sky and, with the correct fitting of the apparatus, 0.5 mm behind it;
• And also two spring modules that carry out the distalization of molars.

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Devices of this type are made individually according to the model of the patient's jaws in the dental laboratory.The doctor receives the finished design on the model of the jaw, fits it in the patient’s oral cavity, and adjusts it if necessary so that the device sits correctly and maximally performs its function. Then the doctor fixes the rings on the teeth with dental cement.

The terms of use of this device on average are from three to six months. Then the orthodontist fixes the palatal arch on the first molars to maintain the achieved position, and the bracket system is fixed on the remaining teeth, which, in fact, completes the treatment that has been started.

When correcting a distal bite, the first and second molars can be displaced without the indicated devices, using the braces immediately. To do this, at the stage of setting the teeth on rectangular arches, the doctor rigidly binds the teeth with a metal ligature and puts a spring between 6 and 7 teeth. The springs are replaced with stronger springs every 2-3 weeks.

Another effective way of tooth distalization is the use of the facial arch with chin sling and palatine traction. The patient uses the facial arch for 2-3 hours a day and at night.

The photo below shows an example of such a correction:

To set the lower jaw in the front position using intermaxillary elastic traction. If the doctor's recommendations are followed, the result can be achieved in about 3-4 months of treatment.

If it was not possible to achieve the desired result after the appointment of intermaxillary traction, then the doctor fixes the Herbst apparatus described above.

With a severe degree of a distal bite, when its cause lies in the strongly expressed anomalies of the development and correlation of the jaw bones, one has to resort to the help of the maxillofacial surgeon and correct the bite surgically. If the patient agrees to surgery, then the orthodontist together with the surgeon draw up a joint plan for preparing the patient for surgery and rehabilitation in the postoperative period.

In many forums today, one often encounters disputes about whether or not to agree to such an operation. People often criticize the treatment plan proposed to other people, while forgetting that the treatment plan of a particular patient is made by the orthodontist based on the medical history, severity of the disease and the result that the patient seeks.

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In this case, we are talking about the so-called orthognathic operation, which is carried out in the operating room. The surgeon makes an incision in the soft tissues to expose the underlying bone, then the bone is sawn and extended to the desired position, after which the jaw is fixed in a new position with the help of metal plates made of titanium nickelide. In the hospital, the patient spends from 5 days to a week to monitor the condition.

Despite the seemingly rather scary description, in reality, an orthognathic operation is today a well-established and non-hazardous procedure.

If, with a severe degree of distal occlusion, the patient strongly disagrees with the surgical stage of treatment, then the orthodontist corrects the occlusion only partially: so that the dental arches are even. However, the position of the jaw bones relative to the base of the skull remains unchanged in this case, that is, the profile of the patient’s face does not change.

 

How to prevent the development of a distal bite

To prevent the formation of a distal bite, first of all, it is necessary to monitor the development of the child from early childhood. Timely wean him from using a nipple, sucking a finger, propping his chin with his fist, introduce fresh (and, therefore, quite hard) fruits and vegetables into the diet. Correct other bad habits.

Do not start the condition of milk teeth, believing that since they are temporary, then it is not necessary to treat them - in fact, on the contrary, they need to be treated in a timely manner so that there are no problems with permanent teeth.An important task is to preserve milk teeth until their natural change, without leading to their removal due to caries or pulpitis.

It is also useful to visit the orthodontist to control the growth and development of the dentition in general.

 

So to summarize. Distal bite is a very common pathology of the population of Europe and the European part of Russia. The state of the dentofacial system formed by a distal bite requires treatment, and you should not think that if you do not intervene, then there will be nothing wrong and everything will somehow "resolve". Alas, it will not resolve.

In the future, an uncorrected distal bite can cause a violation of the temporomandibular joint function (chewing pains, regular headaches), abnormal tooth abrasion (there will be nothing to chew on aging), and in some cases it can cause early tooth loss and psychological problems. In addition, many people with a distal bite do not even realize that they could look more attractive if their face profile was not distorted by anomalous bite.

Therefore, if you see signs of a problem in yourself or your child, then do not waste time, it is best to solve it in the early stages.

Be healthy!

 

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