distal position. Determination of the mesio-distal position of the lower jaw

The distal occlusion, or prognathia, is a common deformity, more common in mixed dentition than in milk and permanent dentition. This is explained, on the one hand, by the unstable relative physiological balance of the dentition during the period of tooth change, and on the other hand, by the fact that some forms of this anomaly disappear during the final formation of the masticatory apparatus as a result of self-regulation due to the intensive growth of the lower jaw.

The distal occlusion occurs as an independent deformity, but is more often aggravated by anomalies in the position of individual teeth, an open or deep bite, as well as a sharp narrowing of the jaws. The deformation is expressed in the forward protrusion of the teeth of the upper jaw, the lower one is displaced backwards, the chin is, as it were, beveled backwards, the angle of the lower jaw is reduced. In many children with an overbite, the mouth is slightly open and the lips do not close. The upper lip is short and does not cover the upper front teeth. The lower lip is placed behind the upper teeth and is adjacent to their palatal surface. The upper frontal teeth are displaced vestibularly, there are gaps between them, or they are located close to each other (Fig. 130).

With distal bite, there is often a decrease in the size of the lower jaw, a sharp curvature of the occlusal plane (the frontal teeth are higher than the level of the chewing teeth), there is no cutting-cusp contact between the frontal teeth, sometimes there is crowding of the teeth in the frontal area and the inclination of the chewing teeth in the lingual direction. Changed the shape of the alveolar processes and the palate. The alveolar processes are sometimes narrowed, the upper jaw takes on a U-shape, and sometimes a V-shape, the palate is high. The mucous membrane of the oral cavity, especially the gingival margin in the region of the frontal teeth, is hyperemic, edematous, and on the palatine side of the upper jaw is injured by the lower teeth.

The most common causes of distal occlusion include a combination of diseases of early childhood with artificial feeding, breathing disorders through the nose, bad habits (sucking the thumb and biting the lower lip), pathology of the teeth in the milk occlusion. A special place in the etiology of distal occlusion is given to a hereditary or constitutional factor.

Distal occlusion may occur as a result of morphological deviations within the dentition and in the area of ​​the alveolar process of the jaws, discrepancies in the size of the body of the upper and lower jaws and the size of the branches of the lower jaw, incorrect location of the jaws in the skull or displacement of the lower jaw.

Sometimes an underbite is the result of a slowdown in the growth and development of the jaws.

Lower micrognathia or microgenia is condylar and extra-condylar. The mechanism of development of condylar microgenia is based on primary lesions (trauma, chronic inflammation, radiation, etc.) of the articular process as the center of longitudinal growth of the lower jaw. These microgenies are characterized by a pronounced shortening of the jaw body with less reduced alveolar and dental arches.

Extracondylar microgenias have a different pathogenesis of development (congenital absence or removal of tooth germs, inflammation or trauma in the area of ​​foci of increased appositional activity), but the unifying point is that they arise in connection with the suppression or shutdown of mechanisms that are important for the development of the lower jaw.

Distal bite often occurs in children with endocrinopathies, for example, in girls with Shereshevsky-Turner syndrome.

According to Angle's classification, the distal occlusion belongs to the second class, it is determined by the distal shift of the lower jaw and the disturbed ratio in the area of ​​the first molars.

According to the classification of A. I. Betelman (1959), distal occlusion refers to anomalies in the sagittal and has the following four clinical forms:

• 1) lower micrognathia with a normal upper jaw;
• 2) upper macrognathia with a normal lower jaw;
• 3) upper macrognathia and lower micrognathia;
• 4) maxillary prognathism with compression in the lateral areas.

Depending on the shape and size of the dental arches, the position of the upper frontal teeth, the lower jaw and taking into account etiological factors, Yu. M. Malygin identified the following types of distal occlusion:

• 1) without deformation of the dental arches;
• 2) with lateral displacement of the lower jaw with habitual occlusion;
• 3) with a close position of the upper frontal teeth and narrowing of the dental arches with their normal length;
• 4) with elongation of the upper dentition, protrusion of the upper incisors with tremas and a normal width of the dental arches;
• 5) with elongation of the upper dental arch, protrusion of the upper incisors, tremas and narrowing of the dentition;
• 6) with elongation of the upper (and sometimes lower) dental arch, protrusion of the upper frontal teeth with their tight position and narrowing of the dental arches;
• 7) with asymmetry of the upper (and sometimes lower) dental arches with unilateral shortening and expansion of the dental arch from the opposite side; protrusion of the upper incisors on one side and their retrusion on the other side;
• 8) with shortening of the dental arches, retrusion of the upper central incisors and protrusion of the lateral ones with a normal width of the dental arches;
• 9) with shortening and narrowing of the dental arches and protrusion of all incisors.

This characteristic of the varieties of distal occlusion reflects the increase in deviations and makes it easier to determine the degree of difficulty of orthodontic treatment, given the severity of the violations.

F. Ya. Khoroshilkina, based on the study of lateral teleroentgenograms of the head, identified three forms of distal occlusion: dentoalveolar, gnathic and combined.

The first form of this pathology develops as a result of the abnormal position of individual teeth, their groups, or changes in the shape of the alveolar process. A common feature is the discrepancy between the length of the dental arch and its apical base in one or both jaws. There are two types of dentoalveolar form:

• a) displacement of the upper lateral teeth forward with an anterior inclination of the axes of the first upper premolars;
• b) retrusion of the alveolar process of the lower jaw in the frontal area.

With a gnathic form, the upper jaw stands forward, its body is elongated. At the same time, the shape of the face and profile are convex. The body of the mandible is shortened, located more distally due to a decrease in the size of the mandibular angles or the curvature of the necks of the articular processes posteriorly, the branches of the mandible are shortened.

With a combined form, there is an incorrect arrangement of the frontal and lateral teeth, excessive development of the body of the upper jaw and its anterior location or underdevelopment of the lower jaw, its distal location or a small angle of the lower jaw.

Since the distal occlusion is often burdened by a deep one, two forms of comorbidity are distinguished.

With the dentoalveolar form of distal occlusion in combination with a deep bite, there is:

• a) anterior arrangement of the upper dentition with protrusion of the alveolar process;
• b) posterior location of the lower dentition with retrusion of the alveolar process;
• c) posterior location of the upper and lower frontal teeth.

The gnathic form of the distal occlusion may be due to underdevelopment of the body or branches of the lower jaw and due to the distal position of the lower jaw together with the joints in relation to the upper jaw and to the base of the skull, as well as excessive development of the upper jaw or its medial position relative to the lower jaw and skull base .

Distal bite leads to disruption of important functions of the oral cavity: swallowing, chewing, especially biting off food, breathing is difficult, there is an incorrect articulation of the tongue and fuzzy pronunciation of sounds.

The degree of deformation of the occlusal plane, the size of the sagittal gap in the frontal area, the degree of reduction in the masticatory area of ​​the dentition, as well as the absence of medial-distal contact in the area of ​​the first permanent molars affect the nature of the masticatory movements of the lower jaw, and, consequently, the chewing function. With a prognathic ratio of dentition, there is a predominance of crushing or crushing movements of the lower jaw, lengthening of the chewing period, and a decrease in chewing efficiency.

Treatment of distal occlusion depends on the age of the child and the clinical form of the deformity.

In the milk occlusion, interventions are of a therapeutic and prophylactic nature and boil down to creating conditions conducive to the normal development of the child's dentoalveolar apparatus. At the same time, it is necessary to sanitize the oral cavity and the nasal part of the pharynx, to carry out exercises that promote the protrusion of the lower jaw anteriorly, and also to strengthen the tone of the circular muscle of the mouth. To do this, it is recommended to pull down the upper lip and, grabbing it with the lower teeth or lower lip, hold it in this position for several minutes. This technique is repeated several times a day.

In children with a long-standing habit of sucking the lower lip on milk molars, an apparatus consisting of metal trays with a wire soldered to them can be used. The bow is covered in the frontal area with a layer of plastic and turns into a roller that prevents biting or sucking of the lower lip. It is placed at a distance of 2-3 mm from the dentition. A plastic roller can be welded onto a removable plate with a vestibular arch, brought to the frontal part of the lower jaw (Fig. 131).

Vestibular plates can be used in early childhood to treat overbite resulting from thumb or lower lip sucking in combination with impaired nasal breathing. In this case, the plate is designed so that it is in close contact only with the vestibular surface and the cutting edges of the upper incisors and is significantly behind the rest of the teeth and alveolar processes. The stability of the plate is created by nests modeled for the cutting edges of displaced teeth. For the treatment of distal occlusion, aggravated by an open bite resulting from tongue sucking, a vestibular-lingual plate is used. Such a plate is a combination of vestibular and lingual plates, interconnected by a wire passing between the teeth or enveloping the distal surface of the last molars. The lingual plate is modeled in such a way that the tongue rests against the plate.

For weaning to push the tongue between the teeth, such a plate is replaced with a plate with a zigzag wire lattice (Fig. 132). For the treatment of distal occlusion in early childhood (milk and early periods of mixed occlusion), a occlusion shaper is also used.

The basis of the device is located on the lower jaw, the guide plane has a serpentine shape and is made of orthodontic wire with a cross section of 0.8 mm. If it is necessary to simultaneously expand the jaws, an expanding screw and lateral springy inclined planes are introduced into the design of the apparatus. In the position of central occlusion, the elastic loops of the guide plane are superimposed on the labial surface of the anterior teeth of the upper jaw, without touching the mucous membrane. The guide plane exerts constant pressure on the teeth, the strength of which is dosed by the patient. This pressure is simultaneously transmitted to the basis of the apparatus located on the opposite jaw, causing the necessary restructuring of it, resulting in the formation of the correct ratio of teeth, dentition, alveolar processes of both jaws. This device can also be used as a retention device after the elimination of severe forms of distal occlusion.

In children with a distal relation of the jaws in a mixed dentition, treatment is reduced to the use of orthodontic appliances that promote the movement of the lower jaw anteriorly or the displacement of the upper anterior teeth orally.

When choosing orthodontic appliances, preference is given to functionally guiding equipment. The main place in this group of devices is occupied by a bite plate with an inclined plane and crowns for lower deciduous molars with elongated medial tubercles (Fig. 133, 134).

These functionally guiding devices contribute to the redistribution of masticatory pressure and the establishment of the lower jaw in an anteriorly advanced position. In this case, the pressure that occurs during chewing is concentrated on the frontal part of the dentition.

Modeling of the inclined plane is carried out depending on the shape of the distal occlusion, the depth of overlap of the teeth and the size of the sagittal gap, or sagittal step.

Due to the fact that the size of the sagittal gap varies greatly with different forms of distal occlusion, this factor should be taken into account when modeling bite planes in Katz, Schwarz, Khurgina and other devices, where it is the main active part of the device.

In children with a sagittal gap of more than 5 mm, the inclined plane is first modeled in such a way that the lower jaw is displaced anteriorly up to 5 mm (about half of the path that it should follow to the correct ratio), and after 2-3 months. the inclined plane is layered for another 2-5 mm. If the ratio between the dentition after is not improved, the inclined plane is again built up or a new orthodontic appliance is being prepared.

Orthodontic appliances with an inclined plane should be used not only at night, but also during the day and for as long as possible, since during the day the activity of the masticatory muscles is much greater.

In the treatment of severe forms of distal occlusion with deep overlap, the separation between the lateral teeth should be at least 4-5 mm. It is necessary to constantly monitor the separation of the occlusion in the lateral parts of the jaws and, as contacts between the lateral teeth are obtained, again create a separation of the occlusion by thickening with quick-hardening plastic.

When using a plate with a correctly modeled on-piece platform, the lower jaw is held in an extended position, and in the lateral areas the bite will be disconnected. At the same time, the functional load on the muscles that displace the lower jaw posteriorly increases, and enhanced training of the muscles that push the lower jaw anteriorly is provided.

An increase in the tone of the masticatory muscles contributes to an increase in trophic processes in the jaws and a restructuring in the periodontal tissues of teeth that experience increased pressure.

The separation of the bite in the region of the posterior teeth promotes the growth of the alveolar process and thereby reduces the depth of overlap, and also corrects the level of the occlusal surface. The presence of flip clasps in the plate contributes to changing the position of the upper frontal teeth. The plate is modeled so that it does not adhere to the mucous membrane of the frontal area of ​​the palate.

In the treatment of distal occlusion in patients (15-20 years old), with prolonged use of bite plates, a double, or “wandering”, bite is established: in physiological rest, the lower jaw is fixed in a neutral position, and during function it shifts to the previous (distal) position.

If a shortening of the dentition in the upper jaw is shown due to the movement of the anterior teeth in the distal direction, a Schwartz plate or its modifications are used. When correcting the distal occlusion with removable plates, the correction of the apparatus is carried out in the area of ​​its base adhering to the palatine surfaces of the anterior teeth.

The disadvantage of the design of devices with an inclined plane is its solidity, which does not allow you to dose the force for each tooth separately and move it in the right direction. O. M. Basharova proposed an apparatus with a labile elastic inclined plane, consisting of a number of retractors that act on the teeth and on the alveolar processes of the jaws. This is achieved due to the labile connection of the inclined plane with the base and the elasticity of its constituent retractors, which are formed from metal strips 3-4 mm wide and 60-70 mm long. The device creates separation of the lateral sections of the dental arches, which contributes to their growth in the vertical direction in the lateral sections of the jaws and thereby corrects the bite height (Fig. 135).

With mixed dentition, metal crowns with elongated medial tubercles are also used. Crowns are fixed on the second milk or on the first permanent molars of the lower jaw. If the distal bite is aggravated by deep overlap, the elongated tubercle on the crowns is placed in the gap between the first and second primary molars of the upper jaw. The gap between the molars is created by grinding the corresponding surfaces of the milk teeth with a separation disc. An elongated anterior tubercle is installed in the polished gaps on the crown of the lower second primary molar. With the help of such crowns, some separation of the bite is achieved, which contributes to the free growth of the first permanent molars, as a result of which the permanent teeth are set with a lesser degree of overlap.

Where the distal bite is complicated by an open one, the crowns are fixed on the first permanent molars, and their elongated medial tubercle enters the space between the second primary and first permanent molars of the upper jaw. Crowns with elongated medial tubercles contribute to the displacement of the lower jaw anteriorly.

In a mixed bite, when narrowing the upper jaw, the Ainsworth apparatus is used (Fig. 136), consisting of crowns, tubes, internal tangent beams and an external springy arc. Crowns are cemented on the second milk molars, and at an older age - on the second premolars. Tubes are soldered to the crowns from the vestibular side parallel to the vertical axis of the tooth, and tangent wires from the palatal side, exactly adjacent to the teeth to be displaced. The arc must be compressed somewhat before being introduced into the tubes. Due to elasticity, the arch assumes its original position and expands the lateral sections of the dental arch.

A good result of the expansion of the upper jaw can be achieved only when, in parallel with the restructuring in the articulation of the dentition, the chewing and mimic muscles are restructured.

For the treatment of distal occlusion in the shift period, the Andresen-Goypl apparatus is also used. The device is a removable plate, which, covering the palatine and lingual surfaces of the upper and lower teeth, continues on the alveolar processes of both jaws. It is equipped with a labile arc 0.9-1.2 mm thick, extending from the apparatus between the canines and the first premolars, and is located on the vestibular surface of the frontal teeth. A screw or spring loop is fixed on the palatal surface of the plate, designed to achieve a simultaneous expanding effect on both dental arches. For this purpose, the apparatus is sawn along the sagittal plane, and the screw is actuated. The plate at the point of contact with the lower frontal teeth has the form of an inclined plane, which contributes to the movement of the lower jaw in the medial direction.

The upper and lower lateral teeth at the same time rest on the protrusions on the plate: the upper - medial, lower - distal surfaces. To facilitate the movement of the teeth in these directions, it is necessary to free up areas in the places where the plate adheres to the lateral teeth, which is achieved by sawing the distal protrusions on the upper jaw, and the medial protrusions on the lower jaw. The movement of the upper frontal teeth in the sagittal direction is carried out using a springy vestibular arch. The shackle is periodically activated by compressing the vertical loops. On the palatine side, at the necks of the upper frontal teeth, plastic is cut off so that the plate does not adhere to them.

Functionally guiding orthodontic appliances, including the Andresen apparatus, are passive in themselves, but they transfer and direct the pressure force during chewing to certain areas of the occlusal surfaces of the teeth, periodontium and joint and cause a corresponding restructuring in them. The inclined plane in the Andresen-Goipl activator can be made of soft plastic. When using such an activator, the movements of the lower jaw are less constrained, and the pressure on the dentition is reproduced with greater force, since the child can increase the pressure by squeezing the inclined plane, like chewing gum.

A contraindication to the use of the Andresen activator (and other bulky devices) is difficulty breathing through the nose. Children with excessively narrowed and high palate also cannot use the activator. In these cases, at the beginning of treatment, it is necessary to expand the upper jaw with a plate with a screw or Coffin springs.

The combination of functional orthodontic appliances with extraoral support and traction allows to speed up orthodontic treatment by actively arresting the growth of one of the jaws and increasing the load on the teeth.

Some forms of distal occlusion can be treated with the function regulators proposed by Frenkel (Fig. 137). They help to balance the tension of the muscles acting on the teeth and alveolar processes, relieve the dentition narrowed in the lateral areas from the pressure of the cheeks, remove the upper or lower lip from the frontal teeth and thus eliminate the factors that impede the normal development of the jaws.

The essence of this method of treatment differs from other methods. Previously existing devices for the treatment of distal occlusion caused changes first in hard tissues. The Frenkel method is based on primary changes in soft tissues, and then, through natural development and self-regulation, in hard tissues. The device is removable, located in the vestibule of the oral cavity, consists of two shields, two labial pads and connecting wire elements. The regulators of the function have shields of significant size, reaching and even penetrating into the transitional fold. Shields contribute to the irritation of these areas, the change in the tension of the muscle fibers of the transitional fold and the change in the morphology of the bone tissue of the jaws. Lip pads are made on models that are engraved in the area of ​​transitional folds to enhance the irritating effect. The high location of the pads on the upper jaw in the anterior area contributes to the expansion of the nasal passages and the transition of the child to breathing through the nose. The shields are separated from the lateral teeth and the alveolar process of the jaws. This position of the shields is achieved by relieving the pressure of the lips and cheeks from the corresponding parts of the jaws and dentition. When the device is modified, it can be used in later childhood. At the same time, various active wire devices made of wire with a diameter of 0.8-0.9 mm are added to the main parts of the apparatus.

The function regulator of the first type is intended for the treatment of distal occlusion with a fan-shaped arrangement of anterior teeth (second class, first subclass) and anomalies of the first class (according to Angle). To manufacture the regulator, the models are fixed in the occluder in a neutral position, all wire elements are bent, which in the regulator of the first type are the vestibular arch on the upper jaw, the palatine clasp and the lingual arch on the lower jaw. When the sagittal step exceeds 8 mm, the bite is set several times, in these cases the labial pads and lingual arches are rearranged.

The cold mode of polymerization of fast-hardening plastic is carried out in a special boiler at a pressure of 202.6-253.2 kPa (2-2.5 atm) for 30-45 minutes.

The second type function regulator is intended for the treatment of underbite (second class, second subtype) and deep overbite (according to Angle). It is distinguished by the presence of a wire loop that guides the fangs and second incisors. If these teeth need to be moved backwards, a vestibularly located arch is welded into the apparatus. If any teeth, such as central incisors, need to be moved anteriorly, a wire loop is placed on the palatal side. All wire elements must be laid closer to the cutting edge.

Apparatus of the second type helps to develop the lower jaw, can put forward the anterior teeth of the upper jaw, turned anteriorly. The vestibular arch is needed in cases where there are strongly protruding lateral incisors. The lateral shields do not adhere to the upper lateral teeth, which contributes to further expansion of the dental arch.

To expand the upper dentition, you can use the Frenkel apparatus with additional and palatine pads and wire springs. Despite the apparent bulkiness, the device is well located in the mouth, does not impede speech, the tongue freely takes place in the oral cavity, the lips are in a closed state.

After the device is inserted into the oral cavity, the child is asked to talk in the presence of relatives; you need to get used to the device gradually, use it constantly, removing it only during meals; medical control is carried out at least once a month. During the control, the doctor must establish whether the patient keeps his mouth closed and whether the tongue is located on the transversely located arch. Distal bite can be cured in 1.5-2 years.

Every six months, the device is replaced with a new one due to ongoing changes in the oral cavity. A month later, the patient develops the habit of holding the jaws in the desired closure without the apparatus. This device can also be used in the combined treatment of distal occlusion, in which the first premolars are removed.

In permanent occlusion, in addition to all these devices, Angle arcs are also used. Depending on the shape, either intermaxillary traction or an expansive arch is used to expand the upper jaw. When using intermaxillary traction, crowns with tubes are put on the first molars of the upper or lower jaw, into which the arcs are inserted. The arch on the upper jaw is bent so that it fits snugly against the front teeth. Hooks are soldered to it in the area of ​​\u200b\u200bthe fangs. On the lower jaw, the springy arch is bent so that it lags behind the frontal teeth, which are tied to it with a thread ligature. The upper and lower premolars are attached to the arch with a wire or thread ligature. Between the hooks on the arc fixed on the upper jaw and the tube on the crown of the sixth tooth of the lower jaw, an oblique rubber intermaxillary traction (rubber ring) is pulled, which helps to move the sixth tooth of the upper jaw, and then all the teeth in front distally, and the teeth of the lower jaw move medially (Fig. 138).

The intermaxillary rubber traction can also be fixed between the plates with wire bends in the form of hooks on the upper and lower jaws.

To expand the dentition, the expansive Angle arch is fitted on the upper jaw so that it fits snugly against the anterior teeth and is significantly separated from the lateral ones. The lateral teeth, tied with thread ligatures to the orthodontic arch, gradually move vestibularly, which contributes to the expansion of the lateral sections of the dental arch. The anterior teeth, under pressure on them, the arc gradually moves orally. For this purpose, you can use a plate with a screw or Coffin loops (Fig. 139, 140). When expanding the upper jaw, it is necessary to constantly monitor the ratio of the dentition, since sometimes it is necessary to expand the lower jaw as well.

All types of removable plates are fixed on the upper jaw with round or arrow-shaped clasps, Adams clasps, Napadov fixators. Regardless of the design of the clasps, it is necessary to ensure that they do not interfere with the proper closing of the dentition.

Good stability of the orthodontic appliance is the main condition for its regular use and, consequently, for effective treatment.

The expansion of the upper dentition and its apical base can be carried out by opening the median palatal suture. For this purpose, the devices of Nord, Levkovich, Derichsweiler, Malygin, Khoroshilkova are used.

In the treatment of distal occlusion, it is relatively easy to obtain an expansion of the jaw and cure protrusion, but the distal position of the lower jaw is not always eliminated. In addition, after the treatment of distal occlusion by medial movement of the lower jaw, relapses are often observed, and therefore, the size of the upper dental arch is reduced by adapting it to the size of the reduced and displaced lower jaw.

Effective in the treatment of distal bite is the method of bite hypercorrection (A.G. Shubina). Treatment begins with active myogymnastic exercises designed to rebuild myotatic reflexes, develop free movement and hold the lower jaw in the anterior position. Then, within 7-10 days, a temporary (up to 2 hours) hardware fixation of the lower jaw in a constructive occlusion is carried out. Further (the period of active treatment), the lower jaw is fixed permanently in the most extended position with a fixed apparatus while maintaining the function of chewing. The apparatus consists of two metal trays for the frontal teeth of both jaws. On the vestibular side along the central incisal line, hooks are soldered to the kappas, open towards the transitional fold. A wire with a diameter of 1.2 mm is soldered to the kappa of the upper jaw from the lingual side in the form of a sinusoid, which is necessary for fixing the plastic, from which the frontal plane is formed, holding the lower jaw in a hypercorrective position. The finished apparatus is fixed on the teeth, and while eating, the lower jaw is in the position of a hyperconstructive bite. At night, to prevent opening of the mouth and distal displacement of the lower jaw, a ligature is applied to the vestibular hooks of both mouth guards. Duration of treatment - 5-9 months. In this case, an active restructuring of the temporomandibular joint occurs.

Treatment of upper macrognathia with close standing of the anterior teeth is carried out with the extraction of teeth (often the first premolars).

When they are removed, it is also necessary to thin the interdental septum between the canine and the first premolar. This speeds up the process of moving the fangs into the gaps created.

The movement of the fangs is carried out by fixed devices or plates with levers. One of the fixed devices consists of crowns or rings for canines, equipped with beams in the form of brackets, open medially, and crowns with tubes soldered together for the first and second permanent molars. A rubber ring is pulled between the tubes and the vertical beam. The change of rubber traction is usually carried out after 3-4 days. After moving the canines to the place of the removed first premolars, the anterior teeth are moved with a sliding arch or plate with a vestibular arch (Fig. 141).

During treatment, if shortening of the upper dental arch is indicated, the removal of the first premolars is carried out before the eruption of the canines.

When conducting a combined method of treatment, A. N. Gubskaya and V. I. Rura recommend the following apparatus: orthodontic crowns or rings with hooks open medially are made for the lower 3|3 teeth, and a removable plate with a vestibular arch made of wire with a diameter of 0 .6 mm, with fixing clasps made of wire with a diameter of 0.8 mm, the ends of which are bent in the form of hooks open distally.

Between the hooks on the crowns and the hooks on the base of the removable apparatus, a rubber traction is fixed, which ensures the movement of the canines to the place of the removed premolars. A removable plate can be with an inclined plane or a bite pad, depending on the ratio between the dentition in the sagittal and vertical planes.

Correction of the basis of the apparatus is carried out in the cervical part of the displaced teeth from the oral side, as well as in the places where the plate adheres to the palatal surfaces of the anterior teeth. At the end of the treatment, the device can be used as a retention device to fix the achieved results.

To reduce the dental arch by closing the diastema and three between the anterior teeth of the upper jaw, removable devices are used: a Schwartz plate with a retraction arch, which is periodically activated; Katz’s plate in the modification of A. D. Osad-what with elongated clasp-like tangent beams, Gulyaeva’s apparatus, as well as Angle’s sliding arc, etc. Regardless of the method of moving the anterior teeth, when positive results are achieved, retention devices must be used to fix them. Often, the same devices that were used for treatment are used for this, but they are not activated during the retention period.

When treating distal occlusion in adolescence with only orthodontic appliances, it is difficult to achieve the desired results, since a stable articulatory balance has already arisen, persistent myotatic reflexes have been established, and the bones of the jaws, condylar, coronary and alveolar processes have lost the ability to significant plastic transformations. In these cases, orthodontic interventions are combined with surgical preparation.

With macrognathia, a compact osteotomy is performed, which consists in the fact that on the upper jaw above the roots of the teeth to be moved, many damages are applied to the compact layer of the bone. At the same time, the plasticity of bone tissue begins to increase by the end of the second week after surgery, so orthodontic treatment should be started no earlier than 12-16 days after surgical preparation.

Sometimes surgical interventions are combined with prosthetic treatment. For adults with enamel hypoplasia or multiple caries in the area of ​​the anterior teeth, the central or all incisors are removed with alveolotomy in this area of ​​the jaw, followed by sharp grinding of the vestibular surfaces of the canines (sometimes pre-depulped) and covering them with the supporting crowns of the bridge prosthesis.

In severe cases of distal occlusion resulting from microgenia, reconstructive surgery is performed, which consists in lengthening the lower jaw due to osteotomy and spreading of the fragments. The operation is performed on the body or on the branches of the lower jaw.

Thus, the treatment of various forms of distal occlusion is not carried out according to a single method, but requires an individual approach in each individual case. At the same time, it is impossible to confine ourselves to the impact on only one of the jaws, since in the clinic there are almost no isolated anomalies of one jaw without a deviation from the norm of the other.

The morphological and functional unity of both jaws (according to the laws of interdependence of form and function) contributes to the fact that when the shape of one of the jaws changes, the other jaw also changes. Therefore, during treatment, they do not affect one of the jaws, but use devices that have an effect on both jaws. Prevention of distal occlusion consists in combating bad habits, especially thumb sucking, biting the lower lip, in carrying out exercises for the muscles that push the lower jaw forward, as well as the circular muscles of the mouth, in the normalization of respiratory function, in the sanitation of the oral cavity.

As a result of the treatment of distal occlusion, the closing of the lips is restored, breathing is normalized, the vital capacity of the lungs increases, but the treatment prognosis is not always favorable, especially with the expansion of the upper jaw and the movement of the lower jaw anteriorly.

After defining bite height it is necessary to establish the mesio-distal position of the lower jaw in relation to the upper. Despite the complexity of the techniques, determining the last position of the lower jaw presents some difficulties. Due to the loss of a large number of teeth and atrophy of the alveolar process, as well as depletion of the ligamentous apparatus jaw joint the lower jaw protrudes significantly forward, going beyond the upper. She freely allows arbitrary movements and approaches the top more than would be necessary with an intact chewing apparatus. Consequently, when talking or eating, the patient does not need to open his mouth wide, and the movement of the lower jaw is accompanied by a predominantly hinged rotation of the articular head in the articular cavity. With the introduction of bite ridges with a normal height into the mouth, the patient opens his mouth much more and causes the articular head of the lower jaw to protrude onto the articular tubercle.

To counteract the desire of the patient to push the lower jaw forward, you have to resort to various techniques.

After the introduction of bite patterns into the mouth, the patient raises the tip of the tongue to the soft palate. In order to hold the tip of the tongue in the indicated position, on the upper template, closer to the posterior edge, a gypsum ball is first fixed with wax and the patient is asked to support this ball with the tip of the tongue all the time. With this position of the tongue, the lower jaw almost always moves back.

They ask the patient to close his lips correctly, and the surfaces of the rollers should not touch, then they offer him, without opening his lips, to make a swallowing movement, while in most cases the lower jaw assumes a normal position.

In addition, you can use light pressure with the thumb and forefinger of the right hand on the attachment area. masseter muscle with simultaneous light pressure of the soft part of the palm on the patient's chin (Fig. 53).

Rice. 53. The position of the hands when receiving central occlusion.

Strong pressure on the chin to move the lower jaw distally is completely unacceptable, since in this case the articular heads can be advanced in the articular cavity deeper than their normal position. The correct position of the lower jaw can be checked on the face with fingers in the area where the articular heads are located in front of the external auditory canal: if the lower jaw is in a protruding position, then the articular heads will be clearly palpable in front of the normal position. Then, cuts are made on the upper roller, and a heated wax plate is attached to the lower roller, having previously removed a thin strip of wax, and the patient is offered to close his jaws in the position of central occlusion. After that, the wax templates are removed from the oral cavity, cooled in cold water, applied to the models, and the fit of the lower roller to the upper one and of the templates to the models is checked.

When the central occlusion is determined, reference points are marked on the models. teeth for clasps, the boundaries of the future prosthesis and the color of artificial teeth. If there are natural teeth, then artificial ones should not differ from them in color.

Anatomical terminology serves to accurately describe the location of body parts, organs and other anatomical structures in space and in relation to each other in the anatomy of humans and other animals with a bilateral type of body symmetry, a number of terms are used. Moreover, in human anatomy, it has a number of terminological features that are described here and in a separate article.

Terms used

Terms describing the position relative to the center of mass and the longitudinal axis of the body or body outgrowth:

• abaxial(antonym: adaxial) - located farther from the axis.
• Adaxial(antonym: abaxial) - located closer to the axis.
• Apical(antonym: basal) - located at the top.
• Basal(antonym: apical) - located at the base.
• Distal(antonym: proximal) - distant.
• Lateral(antonym: medial) - lateral, lying further from the median plane.
• Medial(antonym: lateral) - median, located closer to the median plane.
• Proximal(antonym: distal) - near.

Terms describing the position relative to the main parts of the body:

• aboral(antonym: adoral) - located on the opposite mouth pole of the body.
• Adoral(antonym: aboral) - located near the mouth.
• Abdominal- abdominal, pertaining to the abdominal region.
• Ventral(antonym: dorsal) - abdominal (anterior).
• Dorsal(antonym: ventral) - dorsal (rear).
• Caudal(antonym: cranial) - tail, located closer to the tail or to the rear end of the body.
• Cranial(antonym: caudal) - head, located closer to the head or to the front end of the body.
• Rostral- nasal, literally - located closer to the beak. Located closer to the head or to the front end of the body.

Main planes and cuts:

• Sagittal- a cut going in the plane of bilateral symmetry of the body.
• Parasagittal- a cut running parallel to the plane of bilateral symmetry of the body.
• Frontal- an incision along the anterior-posterior axis of the body perpendicular to the sagittal.
• Axial- an incision in the transverse plane of the body

Directions

Animals usually have a head at one end of the body, and a tail at the opposite end. The head end in anatomy is called cranial, cranialis(cranium - skull), and the tail is called caudal, caudalis(cauda - tail). On the head itself, they are guided by the nose of the animal, and the direction to its tip is called rostral, rostralis(rostrum - beak, nose).

The surface or side of an animal's body that points upwards against gravity is called dorsal, dorsalis(dordum - back), and the opposite side of the body, which is closest to the ground, when the animal is in its natural position, that is, it walks, flies or swims, - ventral, ventralis(venter - belly). For example, the dorsal fin of a dolphin is located dorsally, and the cow's udder is ventral side.

For limbs, the concepts are true: proximal, proximalis, - for a point less distant from the body, and distal, distalis, - for remote point. The same terms for internal organs mean the distance from the place of origin of this organ (for example: "distal segment of the jejunum").

Right, dexter, And left, sinister, the sides are indicated as they might be seen from the point of view of the animal being studied. Term homolateral, less often ipsilateral denotes a location on the same side, and contralateral- located on the opposite side. Bilaterally- means location on both sides.

Application in human anatomy

All descriptions in human anatomy are based on the belief that the body is in an anatomical stance position, that is, the person stands straight, arms down, palms facing forward.

Areas closer to the head are called top; further - lower. Upper, superior, corresponds to the concept cranial, and the bottom inferior, - concept caudal. Front, anterior, And rear, posterior, correspond to the concepts ventral And dorsal. Moreover, the terms front And rear in relation to four-legged animals are incorrect, you should use the concepts ventral And dorsal.

Designation of directions

Formations lying closer to the median plane - medial, medialis, and located further - lateral, lateralis. Formations located on the median plane are called median, medianus. For example, the cheek is located more lateral wings of the nose, and the tip of the nose - middle structure. If an organ lies between two adjacent structures, it is called intermediate, intermediate.

Formations located closer to the body will proximal in relation to more distant distal. These concepts are also valid in the description of organs. For example, distal the end of the ureter enters the bladder.

Central- located in the center of the body or anatomical region;
peripheral- external, remote from the center.

When describing the position of organs occurring at different depths, the following terms are used: deep, profundus, And surface, superficialis.

Concepts outer, externus, And interior, internus, is used to describe the position of structures in relation to various body cavities.

term visceral, visceralis(viscerus - inside) denote belonging and proximity to any organ. A parietal, parietalis(paries - wall), - means related to any wall. For example, visceral The pleura covers the lungs, while parietal The pleura covers the inside of the chest wall.

Designation of directions on the limbs

The surface of the upper limb relative to the palm is designated by the term palmaris - palmar, and the lower limb relative to the sole - plantaris - plantar.

Can be teeth located in the position of supraocclusion and infraocclusion. An example of supraocclusion is the position of the anterior teeth in a deep bite, and infraocclusion is the position of the anterior teeth in an open bite.

Pregnant supraocclusion or infraocclusion can be not only a whole group of teeth, but also individual teeth. Supraocclusion should be distinguished from the Popov phenomenon, and infraocclusion should be differentiated from incomplete retention. In Popov's phenomenon, the tooth is located above the occlusal surface and is pushed out of the alveolus due to the deposition of bone tissue at the bottom of the alveolus, and not due to excessive development of the alveolus. In this case, the clinical crown is larger than the anatomical one.

With supraocclusion of the tooth also crosses the occlusal surface, but it is not advanced from the alveolus, and its clinical neck coincides with the anatomical one and the tooth is located above the occlusal surface due to excessive development of the alveolar process.

As for the difference infraocclusion from incomplete retention, what they have in common is that the teeth do not reach the occlusal surface, but with retention they deal with teeth that have not completely erupted with a normally developed alveolar process.

Anatomical neck of an impacted tooth is located deep in the alveolus, and the clinical crown is smaller than the anatomical one. With infraocclusion, the clinical crown coincides with the anatomical one, the tooth erupted normally, but the alveolar process is not sufficiently developed.

Cause of supraocclusion often is the removal of antagonists in early childhood. The teeth, without encountering obstacles, go beyond the line of the occlusal surface due to the excessive development of the alveolar process. When an antagonist tooth is removed in adults, the Popov phenomenon is often observed instead of supraocclusion.

Cause of tooth retention often there is an insufficiency of the biological tendency of the tooth to grow due to the pathology of the development of the tooth germ. With infraocclusion, the developmental pathology factor also plays a role, but not of the tooth, but of the alveolar process. The alveolar process is poorly developed. With an open bite, the cause of infraocclusion is the underdevelopment of the premaxillary bone.

Mesial and distal position of the tooth.

Tooth rotation around the vertical axis. The mesial position of the teeth is such an arrangement of the tooth, in which the crown of the latter is directed mesially towards the front teeth, and in the distal position - towards the back of the standing teeth. In the first case, the root is directed distally, in the second - mesial. This position of the tooth is often explained by early extraction in front of or behind the standing tooth. The tooth occupies the gap formed next to it in the dentition, turning around the horizontal axis.

Tooth rotation around its vertical axis is expressed in the fact that the mesial and distal surfaces of the tooth crown are directed one vestibularly, and the other oral. There is a rotation of the tooth, reaching 180 °. Rotations are common in incisors, canines, and premolars. This anomaly can be caused by incorrect budding, lack of space due to displacement of neighboring teeth or due to a preserved milk tooth, and also as a result of an incorrectly positioned antagonist.

Diastemas and crowding of teeth. The presence of a gap between adjacent teeth is called a diastema or trema. Diastema in dentistry is called the gap between the central incisors, which does not disappear even after the eruption of all teeth. Trema is the gap between other teeth.

should be distinguished true diastema from false. Diastema observed when the eruption of the lateral incisors is delayed or developed as a result of a harmful childhood habit - sucking fingers, tongue or lip grabbing - is a false diastema.

Adults may to form a false diastema during periodontal disease due to functional overload of the incisors, which are displaced and fan-shaped. Retention of the canine or central incisors, as well as the development of a neoplasm, can cause a false diastema.

true diastema It is caused by the abnormal development of the frenulum of the upper lip, which (the frenulum) reaches the gap between the central incisors and is embedded in the overdeveloped incisive papilla (papilla incisiva).

Often the cause of diastema is also a thickening of the bone tissue in the midline (the junction of both maxillary bones).

Crowding of teeth arises due to the close position of the teeth due to underdevelopment of the jaws, compression in the region of the lateral sections of the alveolar process, and also due to a discrepancy between the width of the teeth and the size of the jaws.

13.8.6. Anomalies in the position of the teeth

clinical picture. The position of the tooth, which does not correspond to its optimal location in the dentition, is diagnosed as an anomaly of the position. Compared with anomalies in the position of permanent teeth, the anomaly in the position of milk teeth is a rare phenomenon.

Teeth may be in an incorrect position within the dentition or located outside of it. According to the three mutually perpendicular directions, there are six main types of incorrect position of the teeth - four in the horizontal and two in the vertical directions. The teeth can be rotated along the vertical axis. Rarely occurs such an anomaly as a mutual change in the location of the teeth, for example, in the place of the canine - the premolar, and in the place of the premolar - the canine. There are vestibular, oral, distal and mesial positions of the teeth, as well as supra- and infra-positions, tortoanomaly and transposition of the teeth. There are also body displacement and different types of tooth inclination. It should be noted that individual anomalies are rare; usually, malpositioning of the tooth is not optimal in several directions and may be combined with axial tilt or rotation.

The causes of anomalies in the position of the teeth are diverse: violations of the growth of the jaws, the process of development and change of teeth, atypical laying of the rudiments of teeth, a sharp discrepancy between the size of milk and permanent teeth, the presence of supernumerary teeth, macrodentia, etc. The combination of causative factors in various combinations determines the variety of clinical manifestations, which determines the choice of diagnostic methods.

Rice. 13.66. Lateral position 12 (a). Diastema between 11.21 as a result of edentulous 12.22 (b).

Anomalies in the position of the lateral teeth along the sagittal include the mesial and distal position of the teeth.

Distal displacement teeth is the displacement of the tooth from the optimal back along the dentition. In the anterior part of the dentition, it is called lateral: the tooth is further from the sagittal plane and relative to its optimal location (Fig. 13.66). Causes: partial adentia, atypical position of neighboring teeth, violations of teething, tooth replacement, atypical position of the rudiments of teeth, the presence of supernumerary teeth, etc. Diagnosed by examination of the oral cavity. The degree of displacement is determined by closure with antagonist teeth, as well as by special diagnostic methods.

Mesial displacement of the tooth- this is its displacement forward along the dentition. Causes: partial adentia, impaired teething, atypical position of the rudiments of teeth, the presence of supernumerary teeth, etc. It is diagnosed when examining the oral cavity. The degree of displacement is set by closing with the antagonist teeth.

Vestibular position of the tooth. In the direction of the vestibule of the oral cavity, the canine is most often displaced (Fig. 13.67). Causes: narrowing of the dentition, the presence of supernumerary teeth, atypical laying of the rudiments of teeth, stunting of the jaws, trauma of the rudiments of the teeth, early extraction of milk teeth, mesial displacement of adjacent teeth, bad habits, etc. It is diagnosed by examining the oral cavity and jaw models. The degree of vestibular displacement is determined by the alveolar process using methods
immetrometry, symmetrography, etc.

Rice. 13.67. Vestibular position of the upper canines.

To clarify the relationship of a dystopic tooth with erupting teeth, an X-ray examination should be performed. With dystopia of both upper canines, panoramic radiography or orthopantomography is appropriate.

The vestibular position of the front teeth is characterized by the displacement of the incisors towards the lips.

Causes: tooth displacement, lack of space in the dentition, the presence of supernumerary teeth, macrodentia, impaired development and eruption of teeth, tongue function, nasal breathing, narrowing of the dentition, excessive growth of the alveolar process, bad habits.

Diagnosed by examination of the oral cavity. The degree of displacement of the teeth is determined by the closure of adjacent and antagonist teeth, as well as by the Korkhaus, Howley-Gerber-Gerbst methods.

Oral position of the teeth. Distinguish between the lingual position of the teeth in the lower jaw and the palatine position in the upper jaw.

In the lingual (lingual) position, the tooth on the lower jaw is displaced towards the tongue. This is most common during the period of changing teeth. More often, incisors and premolars are in this position with insufficient space in the dentition and the wrong direction of tooth eruption. Diagnostic methods are the same as for the vestibular position of the teeth. With lingual displacement of the incisors, an analysis of the jaw models according to Korkhauz is used to clarify the degree of displacement.

The palatal (palatinal) position of the tooth is characterized by its displacement on the upper jaw in the palatal direction. The most common causes are lack of space in the dentition and the wrong direction of tooth eruption. During the period of eruption of milk teeth, it is noted very rarely, mainly in the second half during their change and permanent occlusion.

The palatal (palatal) position of the tooth in the anterior part of the upper dentition is characterized by the displacement of the tooth towards the palate. More often in this position are the central incisors. The most common causes are insufficient space in the dentition, underdevelopment of the alveolar process of the upper jaw in the anterior section, bad habits, macrodentia, the presence of supernumerary teeth, a violation of the process of changing teeth, etc. This anomaly is diagnosed when examining the oral cavity. The degree of displacement of the tooth is determined by its ratio with adjacent teeth and antagonist teeth, as well as by Korkhauz and teleradiography methods.

Anomalies in the vertical position of the teeth. Distinguish supra- and infraposition of teeth, tortoanomaly. supraposition is the displacement of the tooth in the vertical direction when the tooth is above the occlusal curve. Causes: absence of antagonistic teeth in the upper jaw, incomplete dentition in the upper jaw, excessive growth of the alveolar process in the lower jaw and its underdevelopment in the upper jaw. Diagnosed by examination of the mouth. The degree of displacement is set relative to the occlusal plane. The most informative method of teleroentgenography.

Infraposition - displacement of the tooth in the vertical direction when the tooth is below the occlusal curve. Causes: the absence of an antagonist tooth in the lower jaw, incomplete dentition in the lower jaw, excessive growth of the alveolar process in the upper jaw and its underdevelopment in the lower jaw.

Tortoanomaly- turn of the tooth along the vertical axis. The rotation of the tooth can be of varying degrees: from a few degrees to 90 ° and even up to 180 °, when the tooth is turned with the palatal side, for example, in the vestibular direction. Causes: lack of space in the dentition, incorrect position of the tooth germ, the presence of supernumerary teeth, macrodentia. Diagnosed by examination of the oral cavity. The size of the place in the dentition and the degree of tooth reversal are specified by measuring on models. The relative position of the roots of a torto-anomalous tooth and adjacent teeth is determined on an orthopantomogram (Fig. 13.68).

T
disposition- mutual change in the location of the teeth in the dentition, for example, the canine in place of the premolar, and the premolar in place of the canine. Causes: atypical bookmark of the rudiments of teeth. A phenomenon close to transposition is when the rudiments of teeth are mutually displaced as a result of insufficient space or due to provoking factors (supernumerary teeth, odontogenic neoplasms, etc.). In this case, there is an incomplete change in the relative position of the teeth during eruption, expressed to varying degrees in the region of the roots and crowns. Diagnosed by examination of the oral cavity, as well as radiographically.

Rice. 13.68. Tortoanomalous location of the rudiment 11 with a cleft palate, partial primary adentia.

Very often, an anomaly of the teeth is combined with anomalies of the jaws and leads to an anomaly of the closure of the dentition.

Diagnostics is based on the data of the clinical picture, x-ray examination and the study of jaw models.

Treatment anomalies in the position of the teeth. With anomalies in the position of the teeth, the task of the orthodontist is to preliminary normalize the shape and size of the dentition, occlusion. For this purpose, various orthodontic structures are used - both removable and non-removable.

In the distal position, the teeth are moved mesially if there is space in the dentition. The need for mesial movement of the tooth arises when the first molar is removed (according to therapeutic indications), and in this case the second molar moves mesially.

Since such an anomaly refers to the lateral teeth, in devices of any design, the fulcrum is formed in the anterior or lateral section of the corresponding side, and the point of application of force is the moved tooth. If a rubber rod is used to move the tooth at its inclined distal position, the point of application of force is the coronal part of the tooth, while in the case of the body - the crown and root, for which a barbell with a hook is used in the region of the transitional fold.

In lamellar devices and kappa plastic structures, the fulcrum is the hooks welded into the base. In metal structures, the hooks are also soldered in the front section on the corresponding structural elements.

Milk and permanent teeth in the corresponding stage of formation can be moved in the mesial direction with hand-shaped springs (according to Kalvelis). Permanent teeth in the final stage of root formation are also moved by the bracket system both in an oblique-rotational and corpus manner. To move the lateral teeth in the mesial direction, the use of a positioner is ineffective.

Treatment of the mesial position of the teeth carried out individually. With early extraction of the second primary molar or primary adentia of the second premolar of the upper jaw, mesial movement of the first molar is observed. In this regard, the closure of one pair of antagonist teeth is disturbed, namely, the mesial-buccal tubercle of the first molar of the upper jaw is located in front of the intertubercular fissure of the first molar of the lower jaw. In this case, it is possible to maintain the mesial position of the first molar and then it is advisable to move the second molar forward.

E
If the doctor decided to move the first molar in the distal direction in order to achieve good closure with the antagonist teeth, you can use the plate on the upper jaw with a sectoral cut, Kalamkarov's apparatus, Angle's arc. Especially effective is the use of a facial bow with a neck traction. For the first molars, rings with tubes for the facial arch are made. On the side of the distally displaced first molar, a bend is made on the arc, which abuts against the tube, and on the opposite side, the end of the arc does not have a stop and is freely located in the tube. In the anterior section, the facial arch is separated from the anterior teeth. When applying cervical traction, the entire force of the facebow is directed to the first molar, which should be moved in the distal direction. For distal movement of both first molars on the facial arch, there are stops in front of the tubes on both sides, and both teeth will move in the distal direction (Fig. 13.69).

Rice. 13.69. Distal movement of the first molars with the help of a facial arch and cervical traction: unilateral (left), bilateral (right).

After moving the first molars in the distal direction, the integrity of the dentition is restored at the level of the second premolar by only prosthetics or with preliminary implantation. In the clinic, the mesial position of the posterior teeth is often found. This may be due to the early removal of the milk canine, the high position of the permanent canine germ, the presence of the supernumerary tooth germ, macrodentia of the posterior teeth, a change in the order of eruption of the canine and the second premolar (the second premolar erupts first). In this case, the type of closure of the lateral teeth corresponds to Angle's class II. In order to create space for the canine, it is necessary to move the posterior teeth distally. To do this, you can use plate devices.

Apparatus 1 and 2 allow you to move in the distal direction of the lateral group of teeth on both sides. In this case, the front teeth are moved in the labial direction.

The plate device 3 (the plate on the upper jaw with a sectoral cut) moves the lateral teeth in the distal direction, and the device 4 allows using the vestibular arch with an M-shaped bend to move the canine in the same direction (the end of the arc is welded into the distal part of the cut). Apparatuses 5 and 7 move the molars in the distal direction, and apparatus 6 - one molar.

TO
The bark can be moved distally using the structures shown in Fig. 13.70. The main problem that arises when moving the canine in the distal direction is its initial position. The choice of an orthodontic appliance and the direction of the acting force depend on the position of the crown and root parts of the tooth.

Rice. 13.70. Orthodontic appliances used for distal movement of teeth.

Treatment lateral position of the teeth. The most typical clinical sign of such an anomaly is the appearance of a gap between the central incisors - diastema.

There are the following types of diastema (Fig. 13.71):

1) symmetrical diastema, in which there is a lateral displacement of the central incisors;

2) diastema with predominant movement of the crowns of the central teeth in the lateral direction from the midline. The roots of the central incisors at the same time retain their position or shift slightly in the lateral direction;

3) diastema, in which the crowns of the central teeth have shifted slightly in the lateral direction from the midline, and the roots of the central incisors have shifted significantly;

Rice. 13.71. Types of diastema.

1 - symmetrical diastema; 2 - lateral displacement of the crowns of the incisors; 3 - lateral displacement of the roots of the incisors; 4 - asymmetric diastema.

4) an asymmetric diastema that occurs when one central incisor has shifted significantly in the lateral direction, while the other central incisor has retained its normal position.

It should be noted that the lateral displacement of the central incisors can be combined with their rotation along the axis of the tooth (tortoanomaly) and vertical displacement of the teeth (dentoalveolar elongation or shortening).

Treatment depends on the clinical picture and the causes of the anomaly. If there is a germ of a supernumerary tooth between the roots of the central incisors, it should be removed. With microdentia of the central incisors, the diastema is eliminated only by prosthetics of the central incisors with solid or metal-ceramic structures. Such prosthetics is carried out in adolescents after 14-15 years. With a diastema caused by microdentia of the lateral incisors, the diastema should be eliminated, and then the prosthetics of the lateral incisors should be made with artificial crowns.

If the maxilla is overdeveloped in the anterior region and a diastema develops, efforts should be made to delay the growth of the maxilla with a plate with a diastema loop and a vestibular arch. At the same time, the loop and U-shaped bends of the vestibular arch are activated. Eliminate and install the canine in place of the missing lateral incisor or move it distally. In the first variant, this can be done when the canine root is located significantly ahead of its proper place in case of its normal eruption. If the mesiodistal size of the canine allows filling the gap formed behind the central incisor, then the tubercle of the canine crown can be abraded and shaped into a lateral incisor. Moving the canine mesially is only possible if the antagonistic teeth allow the canine to create a normal occlusion with them; otherwise, contact with antagonistic teeth (regardless of retention) will cause the canine to move laterally.

With the distal movement of the canine, the gap formed in the area of ​​the missing lateral incisor is eliminated by prosthetics. To do this, it is possible to make a ceramic-metal structure based on a canine and a second fulcrum to select a central incisor by making a paw located on the palatal surface of this tooth. Implantation is also possible.

If the diastema has developed due to the low attachment of the frenulum of the upper lip, plastic surgery of the low attached frenulum is resorted to. Surgical treatment should begin after the eruption of not only the central incisors, but also the lateral ones, i.e. at the age of 8-9 years. There are cases when, after the eruption of the lateral incisors, the diastema disappears by itself.

In the presence of a diastema caused by bad habits, it is necessary to wean children from them, and hypnotherapy is also effective.

With a diastema formed as a result of the abnormal position of the rudiments of the incisors and canines, eruption of not only the incisors, but also the canines is required, after which the diastema may self-eliminate.

Treatment symmetrical diastema is carried out with orthodontic appliances, taking into account the size of the gap between the incisors. With diastema equal to 3 mm or less, you can use a plate on the upper jaw with a loop for the treatment of diastema or with hand-shaped springs. Activation of the loop is carried out 2 times a week by pressing the loop with kampon tongs or pliers. You can also use a plate on the upper jaw with two hand-shaped springs covering the incisors from the lateral side, and hooks open back, between which a rubber ring is applied. To prevent the incisors from turning as they move towards the midline, the wire is bent along the palatal surface of the incisors.

Rice. 13.72. Crowns or rings with rods to eliminate the diastema.

When a diastema is combined with deep incisal occlusion or disocclusion, it is necessary to make a bite pad over the loop. In the treatment of a more pronounced diastema, devices are used that would facilitate the body movement of the incisors and exclude their rotation during movement. To do this, orthodontic crowns (rings) are used on incisors with rods soldered to their vestibular surface with hooks open back, between which a rubber ring is applied. To prevent the rotation of the incisors during their movement, a horizontal tube can be soldered to the ring of one of the teeth, and a wire to the other, one of the ends of which will be soldered horizontally to the crown from the vestibular side, and the other should go into the tube. Thus, the problem of rotation is removed and tension is created to move the teeth (Fig. 13.72).

When treating a diastema with a predominant movement of the crowns of the central incisors, the main load of the orthodontic apparatus should be in the region of the crown part of the incisors. To do this, use a plate on the upper jaw with a loop for the treatment of diastema, hand-shaped springs with hooks open back, with rubber traction between them. It is possible to make orthodontic crowns or rings on the central incisors, solder vertically directed rods with hooks open back to them, and put a rubber band between them.

In diastema, when the crowns of the central incisors have slightly shifted lateral from the midline, and their roots are more significant, it is necessary to create conditions for a more significant movement of the root part of the teeth compared to their crown part. In these cases, a torque is created between the crown and root of the tooth for the correct vertical position of the incisors, and only then the diastema is removed. For this purpose, crowns or rings are made on the central incisors, rods are soldered vertically from the vestibular side. The top end of the rod should be extended and end with a hook open back at 1/2 level root of the tooth or 1/3 from the top of the root of the tooth. Then, a stable Angle arch is superimposed on the dentition, to which a hook, open back, is soldered in the canine area on the opposite side of the dentition. When applying an oblique rubber traction, the tooth root experiences a load in the mesial direction, but the rotation of the tooth will not occur, since there is no second traction in the opposite direction. To do this, the lower hook from the bar is open forward, from it the rubber traction will go to the hook, open back, which is soldered to the Angle arch in the canine area on the same side of the dentition.

Instead of an arch, as a support, you can use a plate on the upper jaw with Adams clasps on the first molars and bellied clasps located between the first and second premolars on both sides of the dentition. The ideal technique for correcting this anomaly is the bracket system.

In the treatment of an asymmetric diastema, which occurs when the lateral displacement of one central incisor, only this tooth should be affected. The choice of orthodontic technique depends on the position of the central incisor, which can be different: parallel with an offset from the midline, when the root and crown of the tooth are displaced by the same distance from the midline; the crown of the tooth is displaced more significantly than its root, the root of the tooth is more significantly than its crown. Lateral displacement of the central incisor can be combined with its torto-anomaly, as well as with dentoalveolar lengthening or shortening.

With this form of diastema, the central incisor, located normally, can serve as a fulcrum when moving the abnormal incisor. To eliminate an asymmetric diastema, it is possible to make a plate for the upper jaw with a hand-shaped spring covering the movable incisor from the distal side. As a support, Adams clasps are used on the first molars, button clasps and a round clasp on the central incisor, located correctly. You can make a hand-shaped spring with hooks open to the back, and put a rubber band between it and a second hook located on a round clasp and also open to the back.

With a more pronounced diastema, a crown or ring is made on a displaced tooth with a guide tube, as described above.

Very often, diastema is accompanied by protrusion of the upper front teeth. In this case, along with the treatment of the diastema, the anterior portion of the upper dentition should be flattened. For this purpose, it is more correct to make a plate for the upper jaw with hand-shaped springs by 1 | 1 to correct the diastema and a vestibular arch with U-shaped bends coated with vinyl chloride.

In recent years, orthodontic appliances have been used to eliminate the diastema in dental practice - positioners.

Treatment vestibular position of the teeth. Permanent teeth with formed roots from the vestibular position are moved by the Angle arc, and, depending on the combination with anomalies in the size and shape of the dentition, both stationary and sliding arcs are used. Since the bracket system is universal, it is meant to use its design features to normalize the position of permanent teeth in the vestibular position. In the appropriate stage of the formation of the roots and periodontium of permanent teeth, it is possible to use a positioner.

H
normalization of the position of the anterior teeth, located vestibular, is carried out, as well as the normalization of the position of the lateral teeth. However, the morphological, functional and topographic features of the anterior teeth determine the possibility of using devices of specific designs and a different combination of their structural elements. So, in children with milk teeth and during their change, vestibular retracting arches are widely used (Fig. 13.73, 1-6). Naturally, the design of the device is determined by a complex of clinical manifestations.

Rice. 13.73. Vestibular retracting arches.

One of the features of the normalization of the labially located upper teeth is also the use of a facial arch. It should be said that the use of positioners to eliminate the labial position of the anterior teeth is more effective than when moving other teeth.

Treatment of the vestibular (labial) position of the lower front teeth is carried out with a retracting arch with a vinyl chloride coating in the presence of three and diastema between the teeth (see Fig. 13.73).

With protrusion of the lower anterior teeth and the absence of three and diastema between them, one should follow the path of removing complete teeth (often the first premolars). The choice of treatment method depends on the size of the teeth and the type of closure of the first molars and canines. The canine often occupies a vestibular position, which is called dystopia, and it is necessary to find out if there is a place for it in the dentition. Canine dystopia may occur as a result of a violation of teething and the sequence of teething. So, very often, after the eruption of the first premolar of the upper jaw, the eruption of the second premolar, and not the canine, follows. In this regard, and taking into account the mesial position of the teeth during their eruption, the canine has no place in the dentition and it erupts either in the vestibular or in the oral direction.

Canine dystopia occurs with macrodentia of the upper anterior teeth, which take the place of the canine. It can also occur in the presence of supernumerary teeth, narrowing of the dentition, early removal of the milk canine (in this case, a mesial displacement of the lateral teeth occurs). Clinically, the mesial shift of the lateral teeth can be determined by the closure of these teeth with antagonist teeth. On this side of the dentition, the closing of the lateral teeth occurs according to Angle's class II, and on the opposite side - according to class I.