Open bite: causes, symptoms, diagnosis, treatment

According to literature, open bite (mordex apertus) occurs in 1.7% of children, more often at an older age than at a younger age.

This type of bite accounts for 1-2% of the total number of its violations.

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What causes open bite?

An open bite is usually associated with rickets, underdevelopment of the intermaxillary bone, bad habits, insufficient biological potential for eruption, which is expressed by tooth retention or too late eruption. Of great importance is the disruption of nasal breathing in early childhood.

An open bite is not an independent nosological form of the disease, but only a symptom of one of many disorders of the dental-jaw system. Thus, it can arise as a result of underdevelopment of one of the alveolar processes (upper or lower jaw) or both at the same time.

An open bite can be a symptom of excessive development and protrusion of the entire upper or lower jaw, or only its frontal section. In all these cases, it is impossible to bite off food due to the lack of contact between the front teeth. Thus, with an open bite, there is no contact between the front and side teeth, either vertically or horizontally.

There are 4 forms of open bite:

• I - arising from deformations of the frontal part of the upper jaw;
• II - caused by deformation of the distal part of the upper jaw;
• III - caused by deformation of the lower jaw;
• IV - caused by deformation of both jaws.

Symptoms of open bite

Symptoms of an open bite are characterized by the fact that when the teeth close, a more or less pronounced vertical slit-like gap is formed between the front and side teeth of the upper and lower jaws.

Symptoms of open bite are largely determined by the length of the gap in the vertical and horizontal directions. Depending on the vertical size, there are 3 degrees of gap size:

1. up to 2 mm;
2. from 3 to 5 mm;
3. 5 mm and more.

According to length, there are also 3 types of gaps:

1. Do not articulate all or part of the front teeth;
2. The front teeth and premolars do not articulate;
3. Only the second molars articulate.

As a result of the above changes, the patient's mouth is open or half-open, the lips do not close. The front teeth often have more or less pronounced signs of hypoplasia. The line of the cutting edges of the front teeth is concave. In this case, an open bite can be caused by the concavity of one (upper or lower) occlusal curve, or both.

There is excessive development of the alveolar processes in the lateral parts of the jaws and underdevelopment in the anterior part, especially the intermaxillary bone.

The degree of separation of teeth in the frontal area can reach 1.5 cm or more. The upper lip in some cases takes an extended position, the lower labial fold is smoothed out, as patients strive hard to hide their defect, trying to cover their mouth.

In other cases, when the orbicularis oris muscle is inactive, the upper lip may be shortened, underdeveloped and flattened. In this case, the oral slit is gaping and has oval outlines, which causes unclear speech and spitting during conversation.

Constant dryness of the mucous membrane of the gums and tongue leads to their chronic inflammation.

Such patients are withdrawn, shy, and feel inferior.

Violation of occlusion and articulation leads to significant disruption of chewing function - the inability to bite off and difficulty in crushing and grinding food.

According to mastication data, in all examined patients the total period of chewing and the number of chewing waves were increased.

The period of initial food fragmentation (normally equal to 1-2 s) in patients lasts from 3 to 10 s, and the duration of the chewing period (normally 14-14.5 s) increases to 44 sec.

As a result of chewing dysfunction with a combination of open bite and deformation of both jaws, the loss of chewing efficiency reaches 75.8%, with a combination of open bite and deformation of the upper jaw, it decreases by 62.1%, and with its combination with deformation of the lower jaw - by 47.94%. The loss of chewing efficiency in different patients ranges from 27 to 88%.

Impaired chewing function leads to various gastrointestinal disorders (in approximately 30% of patients).

Patients complain of impaired chewing (biting and chewing food), and an unaesthetic appearance due to the lengthening of the lower third of the face.

When an open bite is combined with prognathism, patients are distressed by the predatory expression on their face caused by the protrusion of the chin.

They often feel dry mouth due to the prevalence of oral rather than nasal breathing. In addition, patients complain of abundant tartar deposits in the area of inactive (not closing with antagonists) teeth.

Open bite diagnostics

Diagnosis of open bite should be carried out taking into account the need to identify other, concomitant or secondary dental and jaw deformations, so that, based on such a detailed diagnosis, the doctor could determine the prospects for conservative and surgical treatment. In this case, it is advisable to be guided by the classification of P. F. Mazanov, who identifies 4 forms of open bite:

• I - open bite, combined with underdevelopment or deformation of the anterior part of the alveolar process of the upper or lower jaw;
• II - open bite combined with mandibular prognathism;
• III - open bite combined with maxillary prognathism;
• IV - mixed form, in which an open bite is combined with an anomaly in the development of one or both jaws, alveolar processes and teeth.

A. V. Klementov (1957) recommends distinguishing 3 degrees of each form of open bite:

1. the distance between the first upper and lower incisors is less than 0.5 cm;
2. this distance is from 0.5 to 0.9 cm;
3. the distance between the incisors is 1 cm or more, but without signs of the beginning of tooth articulation.

This classification differs from the others in that it covers all types of open bite, including as a component of a more complex deformation of the entire dental system.

To determine the distance between the antagonist incisors, A. V. Klementov suggests using a triangular plexiglass plate with a scale applied to it.

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Treatment of open bite

Treatment of open bite can be conservative (orthodontic), surgical and combined depending on the patient's age, the nature and severity of the deformation. Thus, in early childhood, treatment is usually orthodontic, and its method depends on the child's age and clinical picture.

During the period of milk bite, for example, they resort to preventive measures aimed at reducing the effect of the pathogenetic factor (rickets, bad habits, etc.). For this, in addition to general therapeutic effects, they use specially developed myogymnastics and a chin sling with elastic traction from the bottom up.

During the period of mixed dentition, in addition to myogymnastics, biological and hardware treatment methods are used to increase the bite of the crown (for example, on the sixth teeth) or mouth guards, etc.

In older children (in the second half of the mixed dentition and during the period of permanent dentition), therapeutic measures should be aimed at enhancing the development of the anterior segment of the alveolar processes: intermaxillary traction according to Z. F. Vasilevskaya, grinding down of contact “points” at articulating teeth, Angle’s spring arch, etc.

Main types of surgical interventions for open bite

Some of the operations have already been discussed in the section on overdevelopment of the lower jaw.

Two variants of gentle osteotomy of the anterior part of the upper jaw according to Yu. I. Bernadsky

• Option I is indicated in cases where the open bite is caused by underdevelopment of the anterior section of the alveolar process of the upper jaw in the absence of signs of its protrusion forward. In this case, only some lowering of the resected section of the jaw is necessary to achieve contact with the lower teeth.
• Option II of the operation is applicable when an open bite is combined with a protrusion (forward protrusion) of the anterior portion of the alveolar process and the entire group of upper frontal teeth.

Both versions of the operation have much in common with similar operations by Cohn-Stock, Spanier (Fig. 296), G. I. Semenchenko, P. F. Mazanova, Wassmund, and others.

My technique is distinguished, firstly, by the fact that it involves submucous osteotomy of the bone both from the side of the oral vestibule and from the side of the oral cavity (from the palatal side). This allows us to avoid dissection of the mucous membrane, its wide detachment and the associated threat of necrosis of the entire mobilized frontal section of the upper jaw in the postoperative period. Secondly, no horizontal dissections of the mucous membrane are made in the area of the piriform aperture and nasal septum, but are limited to its detachment and submucous fracture of the base of the nasal septum. Consequently, my technique involves maximum preservation of all sources of blood supply to the soft tissues within the moved section of the jaw.

Option I of the operation is distinguished by the fact that the osteotomy is performed with extremely thin (No. 3) fissure and spear-shaped burs. In this case, it is possible to avoid significant loss of bone substance along the osteotomy line and thereby prevent the displacement of the mobilized fragment of the jaw back, providing it with the ability to shift only downwards.

In option II, the osteotomy is performed not with a thin bur, but with a wide (0.5-0.6 cm) cutter, so that simultaneously with the mobilization of the anterior fragment of the upper jaw, part of it is also resected, which allows the alveolar process and the anterior group of teeth to be displaced not only downwards, but also backwards, and to eliminate 2 defects - open bite and prognathism.

Consequently, variant I of the operation is only an osteotomy, and variant II is a combination of osteotomy with partial resection of the bone substance of the upper jaw (along the osteotomy line).

Methodology of the first variant of submucosal surgery

Small (6-8 mm) vertical incisions are made in the mucous membrane and periosteum on the vestibular and lingual sides along the roots of teeth 5 | 5. The mucous membrane and periosteum are peeled off on both sides of the alveolar process within teeth 543 | 345. The soft tissues are separated from the side of the oral vestibule with a special angular raspatory to the lower edge of the piriform aperture, and from the side of the palate - to the median palatine suture; in the area of the edge of the piriform aperture and the bottom of the nasal cavity, the mucous membrane is separated inward to the anterior nasal spine.

The soft tissues exfoliated in the vestibule of the mouth are taken onto a narrow flat hook-holder, a bur (No. 3-5) is placed under them and, starting from the edge of the pear-shaped aperture, the outer plate of the compact substance of the jaw is dissected (it is important not to damage the apex of the canine root and not to expose the periodontium of the teeth).

The osteotomy line in the alveolar process area is drawn between the root of the canine tooth and the first premolar or between the roots of the premolars (the osteotomy site is chosen before the operation - during the "rehearsal" of the future operation on plaster models). A good reference point is the clearly defined root elevation (juga alveolaria) of the canine tooth. Gradually going deeper, the spongy part of the bone is dissected with burs (which have to be changed frequently, as they quickly become clogged with bone filings).

Having pushed aside the exfoliated soft tissues on the palate with a narrow and flat instrument (L-shaped), an osteotomy is performed with the same burs along the line connecting the space between the roots of teeth 43 | 34 and a point on the sagittal palatine suture at the level of teeth 4 | 4, so as not to damage the powerful vascular-nerve bundle emerging on the palate from the incisive foramen.

Then a vertical incision (0.5 cm) is made in the skin in the area of the base of the anterior edge of the nasal septum (immediately above the anterior nasal spine) and at this level the mucous membrane is peeled off (with a narrow and thin raspatory) from the base of the membranous part of the nasal septum, dissected with a scalpel or scissors from front to back by 1.5-2 cm. In this way the connection of the osteotomized section of the jaw with the cartilage of the nasal septum is broken. If the anterior fragment of the jaw is still held by the uncut bridges of the spongy part, a narrow chisel is inserted into the osteotomy gap and lightly struck with a hammer. After this, the bone becomes completely mobile.

The mobilized fragment of the upper jaw is lowered and placed in the correct position relative to the teeth of the lower jaw. Sutures are applied (from the vein), connecting the exfoliated gingival papillae from the vestibular and lingual sides, as well as 1-2 sutures on the skin in the area of the base of the nasal septum. Using a thin steel or aluminum wire (2 mm in diameter), a smooth dental splint-bracket is applied to the upper jaw; an immobilizing splint made of the vein and quick-hardening plastic can also be applied. It is removed after 5-6 weeks.

When performing an operation using this method, it is possible to do without various types of splinting devices.

II variant of submucosal surgery

The second variant of submucosal surgery begins with the removal of 4 | 4 or 5 | 5 teeth; the width of the crowns of these teeth usually corresponds to the distance by which the frontal section of the upper jaw must be moved backwards. It is better to remove those premolars that are located abnormally (vestibular or oral). After this, the soft tissues are exfoliated in the same way as in the first variant of the surgery.

The osteotomy is performed directly through the alveolus of the extracted tooth, using a cutter that corresponds in diameter to the width of the bone strip to be resected (i.e., to be turned into shavings during the rotation of the cutter). The width of this strip should be the same everywhere and, in turn, correspond to the distance by which the surgeon moves the anterior section of the upper jaw backwards (this is determined before the operation on plaster models, as in the above-described interventions regarding progenia).

If the subperiosteal bed is too small to accommodate a cutter of the required width, a claw scalpel can be used to vertically dissect the periosteum, while maintaining the integrity of the mucous membrane.

After dissecting the periosteum above the site of the upcoming osteotomy, even the thickest metal cutter can be inserted into the submucosal niche.

All subsequent stages of the operation are performed in the same way as in the first version.

The mobilized jaw fragment is displaced backwards, turning the cutting edges of the teeth downwards, into a normognathic position. After this, an excess amount of soft tissue usually appears at the site of the resection-osteotomy. This should not confuse the surgeon, since they soon smooth out on their own.

At the end of the operation, the ridges formed by the soft tissues must be sutured “towards themselves” so that a gap does not form between the bone and the exfoliated tissue.

The jaw fragment displaced backwards and downwards is fixed with one of the dental wire or plastic (made outside the laboratory from quick-hardening plastic) splints for 5-6 weeks.

In conclusion, it is necessary to provide several recommendations for carrying out the described variants of the operation.

If during osteotomy, despite the precautions taken, the vascular-nerve bundle near the apex of a canine or premolar is cut, one should not rush to depulp and fill them, since it has been established that after cutting the vascular-nerve bundle at the apex of the tooth root, its blood supply and innervation are restored. If this does not happen after 2-3 months (which can be checked using an electroodontodiagnostic device), the tooth should be trepanned, the pulp removed from it and filled.

If perforation of the mucous membrane of the maxillary sinus occurs during the operation, this should not cause much concern, since after fixation of the mobilized fragment of the jaw in a new position, the possibility of infection of the sinus from the oral cavity is usually eliminated. In addition, such small focal damage to the healthy mucous membrane of the maxillary sinus is not complicated by diffuse traumatic sinusitis.

In the event of perforation of the mucous membrane of the maxillary sinus, we recommend instilling naphthyzin or sanorin into the patient’s nose for 5-7 days, 3-5 drops 2-3 times a day to ensure free outflow of exudate from the damaged sinus into the nasal cavity.

To prevent overheating of the bone during sawing with burs, it should be periodically irrigated with a cold isotonic solution of sodium chloride or 0.25% novocaine solution. To do this, the blunt end of a long injection needle is brought to the osteotomy site from time to time and the saw line and the heating bur itself are sprayed from a syringe.

Osteotomy of the frontal part of the upper jaw according to P. F. Mazanov

Vertical incisions are made in the mucous membrane and periosteum in the direction from the outer edge of the pyriform aperture to the 5 | 5 teeth. The medial edges of the flaps are peeled off both on the right and on the left, to the level of the line of the proposed osteotomy, i.e. to the 4 | 4 teeth.

Then 4 | 4 (or 5 | 5) teeth located outside the bite are removed, and “tunnels” are formed by peeling back the mucous membrane and periosteum from the palate side in the direction from the alveolus of the removed tooth on the left to the alveolus of the opposite side.

An osteotomy of the bone plate of the upper jaw is performed with a bur from the lip side and from the palate side. A horizontal incision is made in the mucous membrane and periosteum slightly above the transitional fold at the base of the vomer. The vomer is separated and mobility of the anterior fragment of the upper jaw is ensured.

This fragment is displaced into the bite with the lower jaw, sutures are placed on the mucoperiosteal flaps and the mixed fragment of the upper jaw is fixed with rubber rings to the hooks of the splinting devices.

Therefore, unlike the above-described similar operations using our method, the operation according to P. F. Mazanov, firstly, does not provide for preserving the integrity of the mucous membrane and periosteum from the vestibular side (which are cut vertically) and at the base of the nasal septum (cut horizontally). Thus, the blood supply to the frontal part of the jaw is disrupted. Secondly, the method of P. F. Mazanov provides not single-jaw, but intermaxillary fixation of the resected anterior fragment of the jaw, as a result of which the patient is forced to remain with his mouth closed for a long time.

As experimental studies have shown, 1.5-6 months after the operation according to Yu. I. Vernadsky, morphological changes in the dental pulp are less pronounced than in operations according to P. F. Mazanov, K. V. Tkzhalov; the layer of odontoblasts has changed insignificantly, the number of rows of these cells has increased only to 8-10, an accumulation of macrophages, an active process of fibril formation and development of granulation tissue fields are noted in the pulp.

These data confirm the advisability of maintaining the continuity of the mucoperiosteal flaps in the area of the alveolar process and the body of the maxilla in the osteotomy and osteoectomy zone, i.e. the submucosal tunnel approach to the bone. In addition, accelerated healing of bone and soft tissue wounds and preservation of the pulp of the teeth of the maxilla are facilitated by active contractions of the facial and masticatory muscles immediately after surgery, which cannot be ensured with intermaxillary immobilization.