Sinusitis

Distal position. Anomalies in the position of individual teeth

There may 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.

In position supraocclusion or infraocclusion can occur not only in a whole group of teeth, but also in individual teeth. Supraocclusion should be distinguished from the Popov phenomenon, and infraocclusion should be differentiated from incomplete retention. With the Popov 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.

In case of supraocclusion, 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 differences infraocclusion from incomplete retention, then what they have in common is that the teeth do not reach the occlusal surface, but with retention they are dealing with teeth that have not fully erupted with a normally developed alveolar process.

Anatomical neck of an impacted tooth is located deep in the alveoli, and the clinical crown is smaller than the anatomical one. With infraocclusion, the clinical crown coincides with the anatomical one, the tooth has 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 an obstacle, extend 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 impaction often there is insufficiency of the biological tendency of the tooth to grow due to pathology of the development of the tooth germ. With infraocclusion, the factor of developmental pathology also plays a role, but not of the tooth, but of the alveolar process. The alveolar process is poorly developed. In an open bite, the cause of infraocclusion is underdevelopment of the premaxillary bone.

Mesial and distal position of the tooth.

Tooth rotation around a vertical axis. The mesial position of the teeth is the position of the tooth in which the crown of the latter is directed mesially towards the teeth in front, and in the distal position - towards the teeth behind. In the first case, the root is directed distally, in the second - mesially. This position of the tooth is often explained by early extraction of an anterior or posterior tooth. The tooth occupies the gap formed next to it in the dentition, rotating around a 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 orally. There is a tooth rotation reaching 180°. Rotations often occur in incisors, canines and premolars. This anomaly can be caused by incorrect primordia, lack of space due to displacement of adjacent teeth or due to a retained primary tooth, as well as as a result of an incorrectly located antagonist.

Diastemas and crowding of teeth. The presence of a gap between adjacent teeth is called a diastema or trema. In dentistry, a diastema is a gap between the central incisors that does not disappear even after all the teeth have erupted. Trema is the space between other teeth.

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

In adults it may the formation of a false diastema due to periodontal disease due to functional overload of the incisors, which are displaced and arranged in a fan-shaped manner. Retention of the canine or central incisors, as well as the development of a neoplasm, can cause a false diastema.

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

Often caused by diastema There is also thickening of the bone tissue in the midline area (the junction of both maxillary bones).

Crowded teeth occurs due to the close arrangement of teeth due to underdevelopment of the jaws, compression in the lateral areas of the alveolar process, and also due to the discrepancy between the width of the teeth and the size of the jaws.

13.8.6. Anomalies of teeth position

Clinical picture. A tooth position that does not correspond to its optimal location in the dentition is diagnosed as a position anomaly. Compared with anomalies in the position of permanent teeth, anomaly in the position of primary teeth is a rare phenomenon.

Teeth may be in an incorrect position within the dentition or located outside it. According to three mutually perpendicular directions, six main types of incorrect position of teeth are distinguished - four in horizontal and two in vertical directions. The teeth can be rotated along a vertical axis. A rare anomaly occurs such as a mutual change in the location of the teeth, for example, in the place of a canine there is a premolar, and in the place of a premolar there is a canine. There are vestibular, oral, distal and mesial position of the teeth, as well as supra- and infraposition, tortoanomaly and transposition of the teeth. There are also body displacements and different types of tooth inclination. It should be noted that individual anomalies are a rare occurrence; Typically, tooth malposition is suboptimal in several directions and can be combined with tilt or axial rotation.

The causes of anomalies in the position of teeth are varied: disturbances in jaw growth, the process of development and replacement of teeth, atypical formation of tooth buds, a sharp discrepancy in the size of milk and permanent teeth, the presence of supernumerary teeth, macrodentia, etc. The combination of causative factors in various combinations causes a 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 sagittal position of the lateral teeth include the mesial and distal position of the teeth.

Distal displacement teeth - this is the displacement of the tooth from the optimal one back along the dentition. In the anterior portion of the dentition, it is called lateral: the tooth is located further from the sagittal plane and relative to its optimal location (Fig. 13.66). Causes: partial edentia, atypical position of adjacent teeth, disturbances in tooth eruption, change of teeth, atypical position of tooth buds, presence of supernumerary teeth, etc. Diagnosed by examining the oral cavity. The degree of displacement is determined by the closure with antagonist teeth, as well as by special diagnostic methods.

Mesial tooth displacement- this is its displacement forward along the dentition. Causes: partial adentia, impaired teething, atypical position of tooth buds, presence of supernumerary teeth, etc. Diagnosed by examining the oral cavity. The degree of displacement is determined by the closure with the antagonist teeth.

Vestibular position of the tooth. The canine is most often displaced towards the vestibule of the oral cavity (Fig. 13.67). Reasons: narrowing of the dentition, the presence of supernumerary teeth, atypical formation of tooth buds, delayed jaw growth, trauma to the tooth buds, early removal of baby teeth, mesial displacement of adjacent teeth, bad habits, etc. Diagnosed by examining the oral cavity and jaw models. The degree of vestibular displacement is determined by the alveolar process using methods
immetrometry, symmetrometry, etc.

Rice. 13.67. Vestibular position of the upper canines.

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

The vestibular position of the anterior teeth is characterized by a displacement of the incisors towards the lip.

Reasons: tooth displacement, insufficient space in the dentition, the presence of supernumerary teeth, macrodentia, developmental and teething disorders, tongue function, nasal breathing, narrowing of the dentition, excessive growth of the alveolar process, bad habits.

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

Oral position of teeth. A distinction is made between the lingual position of the teeth in the lower jaw and the palatal position in the upper jaw.

In the lingual (lingual) position, the tooth on the lower jaw moves towards the tongue. This is most common during the period of changing teeth. More often, incisors and premolars find themselves in this position when there is insufficient space in the dentition and the direction of tooth eruption is incorrect. The diagnostic methods are the same as for the vestibular position of the teeth. In case of lingual displacement of incisors, analysis of jaw models according to Corkhouse is used to clarify the degree of displacement.

The palatal (palatal) 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 incorrect direction of tooth eruption. During the period of eruption of primary teeth, it is observed very rarely, mainly in the second half during the period of their replacement and permanent dentition.

The palatal (palatal) position of the tooth in the anterior part of the upper dentition is characterized by displacement of the tooth towards the palate. More often than not, the central incisors find themselves in this position. The most common reasons are insufficient space in the dentition, underdevelopment of the alveolar process of the upper jaw in the anterior region, bad habits, macrodentia, the presence of supernumerary teeth, disruption of the process of changing teeth, etc. This anomaly is diagnosed during examination of the oral cavity. The degree of tooth displacement is determined by its relationship with adjacent teeth and antagonist teeth, as well as by Corkhouse and teleradiography methods.

Anomalies in the vertical position of teeth. There are supra- and infra-positions of teeth and tortoanomaly. Supraposition- this is the displacement of the tooth in the vertical direction when the tooth is above the occlusal curve. Reasons: absence of antagonist teeth in the upper jaw, incomplete eruption of teeth in the upper jaw, excessive growth of the alveolar process in the lower jaw and its underdevelopment in the upper jaw. Diagnosed by examining the mouth. The degree of displacement is set relative to the occlusal plane. The most informative method is teleradiography.

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

Tortoanomaly- rotation 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. Reasons: insufficient space in the dentition, incorrect position of the tooth germ, the presence of supernumerary teeth, macrodentia. Diagnosed by examining the oral cavity. The size of the space in the dentition and the degree of tooth rotation are clarified by measuring on models. The relative position of the roots of the tortoanomalous tooth and adjacent teeth is determined on an orthopantomogram (Fig. 13.68).

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

Rice. 13.68. Tortoanomalous location of rudiment 11 in cleft palate, partial primary adentia.

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

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

Treatment anomalies in the position of teeth. In case of anomalies in the position of the teeth, the task of the orthodontist is to preliminary normalize the shape and size of the dentition and 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 tooth movement arises when the first molar is removed (for therapeutic indications), and in this case the second molar moves mesially.

Since this anomaly relates to the lateral teeth, in devices of any design the fulcrum is formed in the anterior or lateral part of the corresponding side, and the point of application of force is the tooth being moved. If a rubber rod is used to move a tooth in an inclined distal position, the point of application of force is the coronal part of the tooth; in the case of a corpus tooth, it is the coronal and root parts, for which a rod with a hook is used in the area of the transitional fold.

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

Primary and permanent teeth at the appropriate stage of formation can be moved in the mesial direction using hand-shaped springs (according to Kalvelis). Permanent teeth in the final stage of root formation are moved using a brace system both obliquely-rotational and corpusally. To move lateral teeth in the mesial direction, the use of a positioner is ineffective.

Treatment of mesial position of teeth carried out individually. With early removal of the second primary molar or primary edentia 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 disrupted, namely the mesial-buccal cusp of the first molar of the upper jaw is located in front of the intercuspal 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.

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

Rice. 13.69. Distal movement of the first molars using a facebow 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 using only prosthetics or with preliminary implantation. In the clinic, the mesial position of the lateral teeth is often encountered. This may be due to early removal of the primary canine, high position of the permanent canine bud, the presence of a supernumerary tooth bud, macrodentia of the lateral teeth, a change in the order of eruption of the canine and second premolar (the second premolar erupts first). In this case, the type of closure of the lateral teeth corresponds to Angle class II. To create space for the canine, the lateral teeth must be moved distally. For this you can use plate devices.

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

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

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The bast can be moved distally using the structures shown in Fig. 13.70. The main problem encountered when moving a canine distally is its initial position. The choice of orthodontic apparatus 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 teeth. The most typical clinical sign of such an anomaly is the appearance of a gap between the central incisors - diastema.

The following types of diastema are distinguished (Fig. 13.71):

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

2) diastema with preferential movement of the crowns of the central teeth in the lateral direction from the midline. The roots of the central incisors retain their position or move 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 incisor crowns; 3 - lateral displacement of the roots of the incisors; 4 - asymmetrical diastema.

4) asymmetrical diastema, which occurs when one central incisor has moved significantly in the lateral direction, while the other central incisor has maintained 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 (dental alveolar lengthening or shortening).

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

If the upper jaw develops excessively in the anterior region and a diastema occurs, one should try to delay the growth of the upper jaw using a plate with a loop for the treatment of diastema and a vestibular arch. At the same time, the loop and U-shaped bends of the vestibular arch are activated. The canine is removed and installed in place of the missing lateral incisor or moved distally. In the first option, this can be done when the root of the canine is located significantly ahead of its proper place in case of normal eruption. If the mesiodistal size of the canine allows filling the gap formed behind the central incisor, then the cusp of the canine crown can be ground down and given the shape of a lateral incisor. Moving the canine mesially is only possible if the antagonist teeth allow the canine to create normal occlusion with them; otherwise, contact with antagonist teeth (regardless of retention) will result in lateral movement of the canine.

When distal movement of the canine occurs, the gap formed in the area of the missing lateral incisor is eliminated by prosthetics. To do this, you can make a metal-ceramic structure with support on the canine and select the central incisor as the second point of support by making a cusp 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, they resort to plastic surgery of the low-attached frenulum. 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 on its own.

If there is a diastema caused by bad habits, it is necessary to wean children from them, and hypnosis therapy is also effective.

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

Treatment symmetrical diastema is carried out using orthodontic appliances, taking into account the size of the gap between the incisors. If the diastema is 3 mm or less, a plate on the upper jaw with a loop for treating diastema or with arm-shaped springs can be used. Activation of the loop is carried out 2 times a week by squeezing the loop with crampon tongs or pliers. You can also use a plate on the upper jaw with two arm-shaped springs covering the incisors from the lateral side, and hooks open to the rear, between which a rubber ring is placed. To prevent rotation of the incisors as they move toward the midline, bend the wire along the palatal surface of the incisors.

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

When a diastema is combined with deep incisal occlusion or disocclusion, it is necessary to make a bite pad on top of the loop. When treating more pronounced diastema, devices are used that would facilitate the body movement of the incisors and would prevent their rotation during movement. To do this, orthodontic crowns (rings) are used on the incisors with rods soldered to their vestibular surface with hooks open to the rear, between which a rubber ring is placed. To prevent rotation of the incisors when moving them, you can solder a horizontal tube 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. This removes the problem of rotation and creates tension for tooth movement (Fig. 13.72).

When treating diastema with predominant movement of the crowns of the central incisors, the main load of the orthodontic apparatus should be in the area of the coronal part of the incisors. To do this, use a plate on the upper jaw with a loop for the treatment of diastema, arm-shaped springs with hooks open to the back, with a rubber rod placed between them. You can make orthodontic crowns or rings for the central incisors, solder vertically directed rods with hooks open to the rear to them, and put a rubber rod between them.

In case of diastema, when the crowns of the central incisors have shifted slightly in the lateral direction 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 rotational moment is created between the crown and root parts of the tooth for the correct vertical position of the incisors, and only then the diastema is eliminated. For this purpose, crowns or rings are made for the central incisors, and rods are soldered vertically on the vestibular side. The top end of the rod should be extended and end with a hook open back at 1/2 level tooth root or 1/3 from the top of the tooth root. Then a stable Angle arch is applied to the dentition, to which a hook open to the rear is soldered in the canine area on the opposite side of the dentition. When an oblique rubber rod is applied, the tooth root experiences a load in the mesial direction, but the tooth does not rotate, since there is no second rod in the opposite direction. To do this, the lower hook from the bar is open forward, from it a rubber rod 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, a plate on the upper jaw with Adams clasps on the first molars and button clasps located between the first and second premolar on both sides of the dentition can be used as a support. The ideal technique to correct this anomaly is braces.

When treating an asymmetrical diastema, which occurs when one central incisor is displaced laterally, only this tooth should be treated. 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 the same distance from the midline; the crown of the tooth is displaced more significantly than its root, the root of the tooth - more significantly than its crown. Lateral displacement of the central incisor can be combined with its tortoanomaly, as well as with dentoalveolar lengthening or shortening.

With this form of diastema, the central incisor, which is normally located, can serve as a fulcrum when moving the abnormal incisor. To eliminate an asymmetrical diastema, a plate can be made for the upper jaw with a hand-shaped spring covering the moving 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 an arm-shaped spring with hooks open back, and put a rubber rod between it and the second hook located on a round clasp and also open back.

For a more pronounced diastema, a crown or ring is made for the tooth being moved with a guide tube, as described above.

Very often, diastema is accompanied by protrusion of the upper front teeth. In this case, along with 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 arm-shaped springs on 1|1 to correct the diastema and a vestibular arch with U-shaped bends with vinyl chloride coating.

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

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

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normalization of the position of the anterior teeth located vestibularly is carried out, as is the normalization of the position of the lateral teeth. However, the morphological, functional and topographical features of the anterior teeth determine the possibility of using devices of specific designs and different combinations of their structural elements. Thus, in children with baby 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 normalization of labially located upper teeth is also the use of a face bow. 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 vinyl chloride coating in the presence of three and diastema between the teeth (see Fig. 13.73).

If there is protrusion of the lower front teeth and the absence of three and diastema between them, one should take the path of removing complete teeth (usually 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 determine whether there is a place for it in the dentition. Canine dystopia can occur as a result of disturbances in the eruption of teeth and the sequence of their eruption. Thus, 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 when they erupt, the canine has no place in the dentition and it erupts either in the vestibular or oral direction.

Dystopia of the canine occurs with macrodentia of the upper front 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 primary canine (in this case, 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 the antagonist teeth. On this side of the dentition, the closure of the lateral teeth occurs according to Engle’s class II, and on the opposite side - according to class I.

Anatomical terminology serves to accurately describe the location of body parts, organs and other anatomical formations 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, human anatomy has a number of terminological features that are described here and in a separate article.

Terms used

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

Abaxial(antonym: adaxial) - located further 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) - middle, located closer to the median plane.
Proximal(antonym: distal) - neighbor.

Terms describing position relative to major body parts:

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

Main planes and sections:

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

Directions

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

The surface or side of an animal's body that points upward, 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 a natural position, that is, walking, flying or swimming - ventral, ventralis(venter - belly). For example, the dorsal fin of a dolphin is located dorsally, and the cow's udder is ventral side.

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

Right, dexter, And left, sinister, the sides are indicated as they would appear from the point of view of the animal being studied. Term homolateral, less often ipsilateral indicates 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 upright, arms down, palms facing forward.

The areas located closer to the head are called top; further - lower. Upper, superior, corresponds to the concept cranial, and the lower one, 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, the concepts should be used ventral And dorsal.

Designation of directions

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

Formations located closer to the body will be proximal in relation to more distant ones, distal. These concepts are also valid when describing 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, distant from the center.

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

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

The term visceral, visceralis(viscerus - inside) indicate belonging and close 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 inner surface 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.

Distal

Terms used

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

Abaxial(antonym: adaxial) - located further 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.
Medial(antonym: lateral) - middle.
Proximal(antonym: distal) - neighbor.

Terms describing position relative to major body parts:

Aboral(antonym: adoral) - located on the pole of the body opposite the mouth.
Adoral(oral) (antonym: aboral) - located near the mouth.
Ventral(antonym: dorsal) - abdominal.
Dorsal(antonym: ventral) - dorsal.
Caudal(antonym: cranial) - caudal, located closer to the tail or to the rear end of the body.
Cranial(antonym: caudal) - cephalic, located closer to the head or to the anterior end of the body.

Main planes and sections:

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

Directions

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

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

Designation of directions

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

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

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

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.

Proximal and distal

Planes

In the anatomy of animals and humans, the concept of the main projection planes is accepted.

The vertical plane divides the body into left and right parts;
the frontal plane divides the body into dorsal and ventral parts;
the horizontal plane divides the body into cranial and caudal parts.

Application in human anatomy

The relationship of the body to the main planes of projection is important in medical imaging systems such as computed tomography, magnetic resonance imaging, and positron emission tomography. In such cases, the body of a person in anatomical stand, is conventionally placed in a three-dimensional rectangular coordinate system. In this case, the plane YX turns out to be located horizontally, the axis X located in the anteroposterior direction, the axis Y goes from left to right or from right to left, and the axis Z is directed up and down, that is, along the human body.

Sagittal plane, XZ, separates the right and left halves of the body. A special case of the sagittal plane is median plane, it runs exactly in the middle of the body, dividing it into two symmetrical halves.
Frontal plane, or coronal, YZ, also located vertically, perpendicular to the sagittal, it separates the anterior (ventral) part of the body from the posterior (dorsal) part.
Horizontal, axial, or transverse plane, XY, perpendicular to the first two and parallel to the surface of the earth, it separates the overlying parts of the body from the underlying ones.

Movements

The term bending, flexio, indicate the movement of one of the bony levers around frontal axis, at which the angle between the articulating bones decreases. For example, when a person sits down, bending the knee joint decreases the angle between the thigh and shin. Movement in the opposite direction, that is, when the limb or torso straightens and the angle between the bony levers increases, is called extension, extensio.

An exception is the ankle (supratalar) joint, in which extension is accompanied by upward movement of the fingers, and when bending, for example, when a person stands on tiptoes, the fingers move downward. Therefore, foot flexion is also called plantar flexion, and extension of the foot is designated by the term dorsiflexion.

With movements around sagittal axis are casting, adductio, And lead, abductio. Adduction is the movement of the bone towards the midplane of the body or (for fingers) to the axis of the limb; abduction characterizes movement in the opposite direction. For example, when the shoulder is abducted, the arm rises to the side, and the fingers are brought together to close them.

Under rotation, rotation, understand the movement of a body part or bone around its longitudinal axis. For example, turning the head occurs due to rotation of the cervical spine. Rotation of the limbs is also referred to as pronation, pronatio, or inward rotation, And supination, supinatio, or outward rotation. With pronation, the palm of the freely hanging upper limb rotates posteriorly, and with supination, it rotates anteriorly. Pronation and supination of the hand are carried out thanks to the proximal and distal radioulnar joints. The lower limb rotates around its axis mainly due to the hip joint; pronation orients the toe of the foot inward, and supination orients it outward. If, when moving around all three axes, the end of a limb describes a circle, such movement is called circular, circumductio.

Anterograde movement along the natural flow of fluids and intestinal contents is called, while movement against the natural flow is called retrograde. Thus, the movement of food from the mouth to the stomach anterograde, and with vomiting - retrograde.

Mnemonic rule for remembering the terms supination and pronation

To remember the direction of movement of the hand during supination and pronation, an analogy with the phrase is usually used “I’m bringing soup, I spilled the soup.”.

The student is asked to stretch his hand forward with the palm up (forward with the limb hanging) and imagine that he is holding a plate of soup on his hand - "I'm bringing soup"- supination. Then he turns his hand palm down (backwards with a free-hanging limb) - "soup spilled"- pronation.

Distal bite- a group of anomalies including deviations in relation to the frontal (orbital, tuberal) plane. The indicated disorders of the facial skeleton and occlusion relate to sagittal anomalies and are characterized by a discrepancy in the size, shape, position of the jaws and dentition in the anteroposterior direction. Some authors call this anomaly prognathia due to the anterior protrusion of the upper jaw in relation to the lower jaw, others call it distal occlusion, posterior, distal occlusion, since the lower jaw is dorsal to the upper jaw.

Etiology and pathogenesis. Distal occlusion is understood as the posterior position of the lower dentition in relation to the upper one, in which the relationship of the first permanent molars and all lateral teeth in the anteroposterior direction is disrupted. E. Angel, in his proposed classification of dental anomalies, classified such disorders as class II, that is, the mesial buccal tubercle of the sixth upper tooth is located anterior to the groove between the mesial and distal buccal tubercles of the lower tooth of the same name. With varying degrees of severity of the anomaly, the anterior buccal tubercle of the sixth upper tooth can close with the lower tooth of the same name or lie in the gap between the second premolar and the first molar of the lower jaw.

Depending on the location of the upper front teeth in class II anomalies, E. Engle identified two subclasses. The first subclass is characterized by a vestibular, fan-shaped deviation of the upper anterior teeth, with or without three teeth, but with the presence of a sagittal gap from several millimeters to one and a half centimeters, and usually with a deep incisal overlap. The second subclass, which is often called a blocking deep bite, is characterized by retrusion of the upper and lower anterior teeth, shortening of the lower third of the face, and the absence, as a rule, of a sagittal gap.

Thus, distal occlusion is caused either by disturbances in the development of the dentoalveolar complex of the jaws, or by skeletal imbalances, or a combination of both. These could be:

upper macrognathia (increase in all or most sizes of the jaw and dentition) with a normal lower jaw, with lower micrognathia or retrognathia;
upper prognathia (anterior position of the jaw) with a normal lower jaw, with lower micrognathia or retrognathia;
distal displacement (inferior retrognathia) or
lower micrognathia with a normal upper jaw (these last two forms are also known in the literature under the name “false prognathia”),
prognathic relationship of the anterior teeth due to inclination (inclination) of the dental and/or alveolar components of the upper and/or lower jaw when closing the sixth teeth according to E. Engle’s class I (neutral closure).

Considering that in practical dentistry the name “prognathia” is very common and popular (meaning the protrusion of the upper jaw in accordance with the Sternfeld classification), in further description of this anomaly we will, for convenience, use this word and “distal bite” as synonyms. If necessary, in particular when differential diagnosis of dentoalveolar and skeletal forms of anomaly or treatment planning, a detailed interpretation will be given.

The causes of distal bite are varied. The development of prognathia may be based on disturbances in the normal uneven development of the jaws observed in the prenatal period. It is known that by the end of the second month of antenatal development, embryos have a prognathic jaw relationship, then a progenic one. By the time of birth, a prognathic relationship of the jaws is again formed (infantile retrogeny), which provides maximum opportunities for natural feeding. This allows a child in infancy to freely move the lower jaw forward during sucking movements, stimulating its anterior growth. Thus, gradually, by the time the child’s primary incisors erupt, the prognathic relationship of the jaws turns into an orthognathic one.

With artificial feeding, especially improper feeding, the child almost does not have to make any effort when sucking, which means that the lower jaw does not grow, which is one of the reasons for the development of a distal bite. These also include neurohumoral factors, disorders of the coordinated work of the masticatory muscles, in particular hyperactivity of the muscles that displace the lower jaw distally, diseases of early childhood (especially rickets), impaired nasal breathing, bad habits, especially thumb sucking, untimely treatment and removal of baby teeth in the absence of prosthetics.

The consequence of premature removal of primary molars is retention of premolars, dystopia of permanent canines, and the Popov Hodon phenomenon in the area of teeth opposing the defect. All this creates a block and prevents normal articulatory movements of the lower jaw. These disorders are irreversible and cannot be self-regulated, since all links of the articulatory chain are involved in the pathological process.

Violation of nasal breathing is of particular importance in the formation of distal occlusion. According to A.A. Pogodina, dental anomalies are combined with impaired nasal breathing in 34% of children, while in children with orthognathic occlusion, nasal breathing is impaired in only 6%. Deviation of the nasal septum, hypertrophy of the inferior turbinates, adenoids on the back wall of the pharynx, enlarged velopharyngeal tonsils and other chronic inflammatory diseases of the upper respiratory tract are a mechanical obstacle to nasal breathing.

R. Fränkel considers dysfunctions of chewing, swallowing, breathing, speech, as well as changes in the tone of the muscles of the perioral region, back of the head and neck due to postural disorders as the root cause of the occurrence of dentoalveolar anomalies. He considers difficulty in nasal breathing and the habit of keeping the mouth open to be especially harmful.

When breathing through the mouth, the upper row of teeth, without internal support for the tongue (it moves down), narrows under the action of the cheek muscles, lengthens and protrudes forward. Weakness of the orbicularis oris muscle contributes to vestibular displacement of the upper anterior teeth. The negative pressure created in the nasal cavity contributes to the formation of a high (“Gothic”) palate.

The prognathic relationship of the dentition (dental alveolar form) may be due to a discrepancy in the size of the crowns of the upper and lower molars. This can be checked using the H.Gerlach and Ton indices. The cause of the anomaly may be incomplete eruption of the molars, vestibular inclination of the upper anterior teeth and the vertical position of the lower ones, distal displacement of the lower jaw. The height of the anterior section of the dentition depends on the degree of deviation of the frontal teeth, therefore, when they protrusion, the arch lengthens, and during retrusion, it shortens.

The main pathogenetic factor of skeletal forms of distal occlusion is F.Ya. Khoroshilkina and E.N. Zhulev is considered to be underdevelopment of the lower jaw or its distal position in the skull. In their opinion, lengthening of the body of the upper jaw and its displacement forward are also common.

Clinical picture. Distal occlusion is (after narrowing of the dentition and deep incisal overlap) the most common anomaly occurring during the period of primary, replacement and permanent teeth. Its population frequency, according to various authors, ranges from 623%, accounting for more than 30% of all dental anomalies.

Distal occlusion is characterized by certain facial features: convexity of the face, sometimes very sharp, often shortening of its lower third, the upper lip is short and the lower lip is located behind the upper incisors, the lips often do not close, in many children the mouth is slightly half-open, the chin fold is pronounced. A tense facial expression and smoothness of its contours are observed when a distal bite is combined with an open bite. The direction of the upper lip depends on the inclination of the teeth, and it can be protruding (class II1 anomaly), flattened with retrusion of the anterior teeth (II2) or their absence.

The height of the upper lip is determined from the base of the nasal septum to the red border and can be large, medium or small. The dimple on the upper lip (philtrum) is very variable, depending on the severity, shape of the alveolar process and can be flat, medium or deep. These signs are of particular importance in case of upper prognathia or progenia. There may be a protruding upper lip, a protruding lower lip, or lips that don't close.

Therefore, important importance is given to the study of the facial profile. F.Ya. Khoroshilkina quite rightly notes that when planning orthodontic treatment, the doctor must clearly understand what lip configuration should be strived for and what facial profile can be obtained after treatment. Lip ratio has prognostic significance. Their location can also be determined in relation to the Ricketts aesthetic plane (a line drawn from the tip of the nose to the protruding part of the chin).

The severity of the distal bite depends on the degree of discrepancy between the size of the apical base of the upper and lower jaw. For dentoalveolar forms of prognathia, a common feature is a discrepancy between the length of the dentition and the apical base on one or both jaws. As an independent nosological form of prognathism, it is rare. Most often it is combined with anomalies in the position of individual teeth, narrowing of the jaws, deep bite, and less often with an open bite. In the transversal direction, there may be normal overlap of the upper teeth with the lower teeth, unilateral or bilateral lingual occlusion. The main dental signs are the absence of incisal-tubercular contact of the anterior teeth and the closure of the lateral teeth according to E. Engle’s class II.

According to many researchers, the first subclass of distal occlusion (II 1) has a very heterogeneous clinical picture in terms of the nature of the morphological disorders of the facial skeleton, since the position of the gnathic part of the facial skeleton is very variable and it is difficult to identify the most characteristic feature. This form is characterized by protrusion of the upper anterior teeth, which can be combined with diastema, trema, as well as their crowding, narrowing of the dentition of the upper jaw, and sometimes the lower, vertical or normal position of the anterior teeth of the lower jaw.

In the second subclass (II2), the morphological changes are more uniform. Upon external examination, the lips are closed, the lower lip is thickened, there is a deep mental fold, the mandibular angles are close to right in size. Unlike II1, the sagittal fissure is usually absent. This form is characterized by a vertical or retruded position of the upper anterior teeth. It should be noted that if the anterior teeth of both jaws are in retrusion, then the correct position of the lower jaw can be assumed. The normal position of the lower anterior teeth and the retruded upper teeth indicate a distal shift of the lower jaw.

Sometimes not all the front teeth are inclined towards the palatine side, but only some of them, for example, the central incisors, while the lateral ones are deviated vestibularly, and even with rotation along the axis. The upper jaw may be U-shaped or V-shaped, with a high palate. The alveolar process is often well defined, but often narrowed, and the apical base is also quite developed. The lower jaw and dentition are usually narrowed, the teeth are closely spaced. The lower incisors are most often in a supraocclusion position and touch the mucous membrane of the palate, on which imprints of their cutting edges are often visible. There is weak development of the alveolar processes in the lateral areas of the jaw. This form of prognathia is almost always combined with a deep bite, which adversely affects not only the configuration of the face, but also the chewing function.

Functional disorders in distal occlusion are expressed in disturbances in biting and crushing food, respiratory function and speech. Chewing efficiency decreases due to a decrease in the useful area of closing teeth, crushing and grinding movements of the lower jaw predominate. Their number and duration of the chewing period increases by an average of 30%. The more pronounced the anomaly, the more significant the disturbances in the movements of the lower jaw and their asymmetry.

Speech disorders are expressed in unclear pronunciation of sounds due to incorrect articulation of the tongue. When swallowing, almost everyone experiences tension in the facial muscles, retraction of the corners of the mouth and lower lip, and a double contour of the chin due to incorrect position of the tongue. The tongue does not push off from the teeth, being located between them, but from the lips and cheeks. Functional dysfunction in distal occlusion largely depends on what other anomalies it is combined with, as well as on the size and topography of dentition defects, if they appear.

X-rays of the temporomandibular joint help establish the shape of its elements and their relationship. Such a study is especially indicated if sagittal movement of the lower jaw is necessary, since the mandibular heads should be correctly located in the articular sockets even after treatment. If they are located normally, that is, in the depths of the fossa, then orthodontic movement of the lower jaw is not indicated.

The mandibular heads can be located distally, and then the joint space in the anterior section will be wider, which confirms the distal displacement of the mandible. Tomograms of the right temporomandibular joint with a section depth of 1.5 cm, taken before and after treatment, show a wide articular fossa (21 mm) and a depth of 10 mm. The articular process is elongated, the mandibular head is inclined forward, the articular tubercle is moderately steep. The width of the joint space in the anterior section before treatment is 2.5 mm, after treatment is 1.5 mm; in the posterior section, 2.0 and 3.0 mm, respectively. The difference in these numbers indicates that there was a distal displacement of the mandible, and during the treatment, the mandibular head moved mesially and is located deep in the articular fossa. This position, along with retrognathia, is often observed in persons who have lost lateral teeth, and in these cases sagittal movement of the lower jaw is indicated. There may also be an asymmetrical arrangement of the mandibular heads, that is, normal on one side and distal on the other. In such patients, the question of the possibility of anterior movement of the mandible must be carefully considered. This must also be observed in the distal position of the head in combination with a steep articular tubercle.

A thorough analysis of occlusal-articulatory relationships and the condition of the temporomandibular joints is necessary to identify muscle-articular dysfunctions, analysis of tomo and zonograms. Absolutely right V.A. Khvatova notes the need for a detailed study of the condition of the muscles and the “arthrogenic” situation before orthodontic treatment. According to her data, in 80% of patients with unfavorable joint conditions, the distal position of the mandibular heads in the usual occlusion was found. The author emphasizes the need to determine the difference between habitual and posterior occlusion (posterior contact position), which is 0.51.2 mm. If such a difference is not determined, and during orthodontic treatment pressure is applied to the joint in the distal direction, then the articular condyle is displaced.

With a distal bite (II 1), when biting food and when speaking, the lower jaw moves forward, the mandibular head moves towards the slope of the articular tubercle, which can cause dysfunction and overload of the joint. In subclass II2, the articular heads may be located not only distally, but also not deep enough; the articular tubercle is often vertical or steep, which makes sagittal movement of the mandible difficult; in such patients, the crushing type of chewing prevails.

The nature of radiocephalometric (teleradiographic) data in distal occlusion depends on its clinical form, in particular, on its combination with gnathic or other disorders of the facial skeleton.

Distal bite against the background: And upper macrognathia is characterized by an increase in all parameters of the upper jaw in absolute numbers, and the dentition can be increased due to large teeth (macrodentia) or due to three, that is, the spaces between the teeth at their usual size

the position in relation to the base of the skull is correct
significant increase in the interapical (interincisal) angle
increase in sagittal interincisal distance

And in upper prognathia, the anterior position of the upper jaw relative to the base of the skull, more often it is combined with II2

jaw dimensions may not change
an increase in the sagittal interincisal distance at II1 and a decrease at II2
increase in interincisal angle at II2
decrease in the angle of inclination of the anterior teeth of the upper jaw to the plane of its base (41-61°, with the norm being 67°)

And lower micrognathia is a decrease in all parameters of the lower jaw, characteristic of its underdevelopment, a decrease in the length of the dentition and, as a rule, crowding of the front teeth

increase in interapical angle
increase in interincisal sagittal distance
reduction of the genial (mandibular) angle
reduction of the intermaxillary (basal) angle

And lower retrognathia is the posterior position of the lower jaw relative to the base of the skull and upper jaw; unlike lower micrognathia, in this case all absolute dimensions will be normal, that is, as with orthognathic occlusion

distal position of the mandible
increase in sagittal interincisal distance
increase in interapical angle
reducing the angle of facial convexity

And the relationship between the apical bases of the jaws is determined by the angle SsNSpm(ANB). Normally, its value is 2.0±2.3°. An increase in the angle over 4° can occur with lower micrognathia and retrognathia or with upper macrognathia and prognathia, as well as with their various combinations. In this case, the relationship of the first permanent molars, as a rule, is according to E. Engle’s class II. For differential diagnosis and detailed clarification of which of these forms occurs, it is necessary to determine the length of the base of the upper and lower jaws. The length of the basal part of the upper jaw (Sna р Snp) is 0.7 of the length of the anterior part of the base of the skull, and the length of the base of the lower jaw (PgGo) is equal to the length of the anterior part of the base of the skull + 3 mm.

Treatment. Distal bite therapy can be carried out using the following methods and techniques:

orthodontic treatment,
hardware-surgical,
surgical,
prosthetic
various combined and combined methods.

During treatment, taking into account certain features depending on the clinical form of the anomaly, the age of the patient, the individual characteristics of the structure of the facial skull and the type of its growth, the following tasks must be solved.

Regulation during the period of jaw growth using a facebow and extraoral traction or a functional apparatus.
Restriction of growth and shortening of the dentition of the upper jaw due to the distal movement of the upper molars, canines and elimination of protrusion of the anterior teeth
When treating distal occlusion, it is advisable to transfer form P2 to form II1, which can be achieved by using arches in the traditional sequence, that is, the primary arch, as a rule, is multi-stranded, flexible, allowing the creation of additional bends when teeth are crowded in order to avoid excessive load on them, then a steel one rectangular.
Distal movement of the upper anterior teeth without or after extraction of individual teeth (most often premolars).
Stimulation of growth and anterior movement of the lower jaw
Expansion of the dentition of the upper and/or lower jaw
Change in interalveolar height and normalization of the Spee curve.
Normalization of the function of masticatory and facial muscles
Retention period

It is not always possible to completely correct the anomaly during these manipulations, but a change in position of approximately 45 mm can be achieved. When planning orthodontic treatment of patients with distal occlusion, teleradiological examination data characterizing the type of growth of the maxillofacial complex, the activity of residual growth and their comparison with orthognathic occlusion are very important.

With a distal occlusion, the proportion of the neutral type of growth decreases (from 71% with orthognathic to 50%) in favor of horizontal, namely to 43% versus 15% with orthognathic. This indicates the predominance of development of the facial skeleton in the anteroposterior direction due to intensive growth of the upper jaw, especially in the period of 7-12 years and somewhat less in 12-15 years. That is why the most optimal for modifying jaw growth are the replacement bite and the earliest permanent bite (for 14-15 years, for 12-13).

In patients with a neutral type of growth of the facial skeleton, the main tasks when correcting a distal bite are, first of all, to restrain the growth of the upper jaw and stimulate the growth of the lower jaw. In such patients, mainly removable equipment of functional or combined action should be used.

With the horizontal type, it is necessary, first of all, to restrain the growth of the upper jaw, with simultaneous distal movement of the lateral teeth, using a face bow with a cervical traction. For adult patients, to reduce the upper dentition, treatment is recommended with the removal of the first premolars, followed by distal displacement of the lateral and anterior teeth. This is indicated for prognathia with a reduced or average size of the base of the upper jaw and for prognathia caused by crowding of the upper front teeth, their sharp protrusion, often together with the alveolar process.

In severe forms of distal occlusion with a pronounced horizontal gap, removal of the first premolars is indicated even in a mixed dentition. After this, when treating II1, you can use a flex arch, then a nitinol one, fixing them first on the teeth of the upper jaw. One of the indications for tooth extraction is a reduction in the retromolar space, which increases the mesial displacement of the lateral teeth and aggravates the close position of the anterior teeth, with insufficient space for the canines of the upper and lower jaw (Zhulev E.N.).

According to W.R. Proffit (1986) indicates that the indication for serial extraction is a discrepancy between the size of the teeth and the dental arch by 10 mm or more, and Ringenberg (1964) believes that the initial value should be smaller, namely 7 mm. According to the point of view of V.P. Norkunaite, with the length of the segment of the dentition “from the distal surfaces of the crowns of the 12th and 22nd teeth to the mesial points of the sixth teeth” equal to 18.5-21.0 mm, and if the sum of the mesiodistal dimensions of the canines and premolars is 22.5-24, 0 mm, then removal of individual permanent teeth is indicated. It should be noted that non-extraction orthodontic treatment is even relatively simpler, since there is no need to move the teeth a significant distance to close the post-extraction gap.

As a last resort, removal of the second molar (sometimes unilateral) is used and distalization of the dentition is performed using a face bow. It is very difficult to move the first molars distally by more than 1.5-2.0 mm even after removing the second molars, since distal tooth displacement is much more difficult than mesial displacement. The latter requires more reliable support and stabilization, as E. Engle wrote about. The extraoral thrust should not be low, otherwise extrusion of the molars will occur.

During the period of replacement teeth, when treating distal deep bite, you can use the forgotten but good method of A. Katz, namely, crowns with spikes on the second milk or first permanent molars (the tooth is not prepared) of the lower jaw. When the mandible is advanced forward, the elongated mesial cusps of the artificial crown should fit into the gap between the first and second primary molars of the upper jaw, widened by preparation. In this case, some separation of the bite occurs, which contributes to the dentoalveolar lengthening of the lateral teeth and a decrease in the incisal overlap. Long-term use of such crowns (8-10 months) leads to the formation of an orthognathic bite.

In children with mixed dentition and a clear tendency to develop distal occlusion, McNamara recommends maxillary expansion with overcorrection, usually a rapid maxilla expander. The subsequent use of a retention plate leads to the movement of the lower jaw to a position more convenient for the patient, pushed forward. This eliminates buccal crossbite and, after some time, improves occlusal relationships in the sagittal direction. Somewhat earlier, this phenomenon was explained by H. Taatz and Reichenbach by the fact that the expansion of the upper jaw contributes to the spontaneous displacement of the lower jaw to the anterior position. If such correction does not occur, then R.G. Alexander recommends the use of a facebow with extraoral traction until the end of the mixed dentition.

In mixed dentition, removable plate devices and a pre-orthodontic trainer are used in the treatment of prognathia.

But in addition to this, when treating anomalies at the dentoalveolar level, especially when combined with a narrowing of the dentition or crowding of teeth, fixed structures can be used. First of all, this is a “2 x 4” device, that is, rings for the first molars and braces for the 4 upper incisors, or utility arches.

Growth can be stimulated using activators, for example Andresen Haüpl or function regulators R.Fränkel. The activator is a removable two-jaw monoblock plastic, functional apparatus, consisting of upper and lower plates connected to each other; a vestibular arch, springs or a screw may be added to them. In addition to the plates adjacent to the inner surface of the alveolar processes, they have a corresponding bed for the oral surfaces of all upper and lower teeth. It is better to fix all types of plates with arrow-shaped clasps and Adams clasps.

The device holds the lower jaw in an extended anterior position (a constructive bite that must be determined by the doctor before treatment), promoting dentoalveolar lengthening in the lateral areas, while the upper anterior teeth are moved posteriorly due to a reciprocal action. On the upper jaw, the plate touches the mesial edges of the surfaces of the teeth, but lags behind the distal ones. On the lower jaw, on the contrary, it fits tightly to the distal edges and lags behind the mesial ones to move the lower jaw.

The clinical laboratory stages of production are as follows.

First clinical impression taking from both jaws; the first laboratory casting of plaster models and making a wax template for the upper jaw with bite ridges to determine the constructive bite, the boundaries of the wax template: in front are the cutting edges of the incisors, behind is a line passing through the middle of the crowns of the last molars, on the side is the chewing surface of the lateral teeth.

The second clinical stage is the determination of a constructive bite: the patient moves the lower jaw forward to a neutral relationship of the first permanent molars (1 class each), and he is asked to close his teeth until they come into contact with the wax. In this case, the separation of the dentition should exceed the “resting height” and it is necessary to monitor the position of the ridge and the coincidence of the midline. If in the position of the constructive bite the neutral closure of the sixth teeth is not achieved and the discrepancy is 45 mm, then this position is fixed. If the sagittal discrepancy exceeds 6 mm, the first activator is first prepared (at 45 mm), and after 6-8 months the second activator is prepared, but with the movement of the lower jaw to the neutral closure of the sixth teeth.

After fixing the constructive bite, the plaster models with a wax template are handed over to the dental technician and the doctor gives him instructions:

make an apparatus with or without a vestibular arch for retrusion of the upper anterior teeth (the shape is being specified),
install a screw or other additional elements, springs, levers, lingual arches, etc. F.Ya. Khoroshilkina and W.R. Proffit proposed installing facebow tubes into the activator (bite blocks in the premolar area) in order to be able, along with the functional action of the device, to create additional distal and vertical force using extraoral traction.

Second laboratory stage: the models are plastered in an occluder, the wax template is removed, a plastic base is made, the listed parts or others (as directed by the doctor), the device is polymerized in a special double cuvette or in a regular one, increasing its vertical size

Third clinical stage: fitting the activator in the oral cavity, first to the upper dentition, and then to the lower one; the activator should fit tightly to the teeth, with lips closed; The rules for using and caring for the device are explained to the patient and the next visit is scheduled. During repeated visits, the device is adjusted in the direction of movement of the upper and lower lateral teeth. During the treatment process, the dental bed is polished according to the direction of movement of the teeth, that is, those that need to be moved in the palatal or lingual direction, and vice versa, the plate should fit tightly to those teeth that need to be moved in the vestibular direction. The device can mainly be used while at home or while sleeping. Treatment is especially successful in the early stages of distal and deep bites.

The device helps restore nasal breathing, since the child is forced to breathe more through the nose due to the closure of the oral fissure by the plate. But it is contraindicated if nasal breathing is completely absent. The activator also helps eliminate the habit of sucking fingers, tongue, lips and various objects. The vestibular deviation of the lower teeth can be prevented by the activator hood, which overlaps them by 1/3 of the height of the crowns, so the plastic in it is polished or the hood is completely removed. Similar actions, depending on the progress of treatment, are taken at each visit. You can also stimulate the advancement of the lower jaw using the Balters bionator.

Treatment of distal occlusion (II2) can be carried out in two stages. First, the upper anterior teeth are deviated, eliminating the blocking of the lower jaw, that is, subclass II2 is transferred to II1 using edgewise therapy, rotating the first molar. The latter should be the first step in the treatment of a class II anomaly if there is a tendency for mesial rotation of the molar around the palatal root. If orthodontic treatment II1 is carried out without tooth extraction, then sometimes it is enough to turn the first upper molar with its buccal surface posteriorly, which allows you to create an additional space of 1.5-3.0-4.0 mm and the subclass will move to II1. This can be done with the help of an extraoral yaga, the Gozhgarin palatal clasp, in which the ends of the clasp, curved in two planes, are fixed into the palatal locks on the molars. The device is activated by unbending the loop.

This treatment method can be used when a class II anomaly is combined with an open bite. To illustrate, we give an example from the clinical practice of Dr. P. Ngan et al.: an 8-year-old patient had closure of the molars on both sides according to E. Engle class II, a 5-millimeter sagittal discrepancy in the frontal area, an anterior open bite and lower retrognathia. The main goal of treatment was to delay the anterior growth of the upper jaw, transfer the molar relationship from class II to class I, reduce concomitant skeletal disorders and open bite.

The treatment apparatus consisted of an activator and an extraoral arch attached to it. Because the base plate of the device did not cover the vault of the palate, a connecting arch (diameter 1.2 mm) was used instead, which increased the space for the tongue. For fixation to the extraoral traction activator, a special tube with a diameter of 1.12 mm (0.045 inches) was mounted in the plastic between the upper and lower dentition. The force of extraoral traction was up to 400 grams on each side. Springs for tilting the front teeth were made of elastic steel wire with a diameter of 0.5-0.6 mm, the lower part of which was fixed with horizontal shanks in plastic. The vertical part of the springs had a point contact in the area of the necks of the teeth.

The mandibular part of the apparatus consisted of an incisal platform for advancing the lower jaw. When determining the constructive bite, the lower jaw moved forward until the incisors made direct contact. In patients with hyperactivity of the muscles of the perioral region, to reduce their effect, lip pads in the form of a “tear” according to R. Fränkel were used, which were located in the vestibule of the oral cavity parallel to the alveolar process. The ratio of molars according to class I. was achieved in about a year and at the same time the size of the open bite decreased, which led to an improvement in the lip relationship. The entire treatment lasted about 14 months.

Sometimes symmetrical or unilateral removal of premolars in the upper jaw is performed. At the second stage of treatment, the lower jaw is set in the correct relationship with the upper. To do this, when there is a sharp narrowing of the lower dentition, it is expanded, and then, based on the clinical picture and X-ray data of the temporomandibular joints, sagittal movement of the lower jaw is carried out using plates with an inclined plane. There are a large number of varieties of plates, including those with an inclined plane. Depending on a particular clinical situation, the doctor selects the appropriate design.

A. Katz's bite block is used to treat prognathia in combination with a deep bite. A special feature of its design is an inclined plane and reversible clasps that bend over the cutting edges of the front teeth onto their vestibular surface. The plate does not adhere to the mucous membrane of the anterior part of the palate and the necks of the anterior teeth. When closing with an inclined plane, the lower teeth slide along its surface, trying to return from a forced (constructive) bite to its original position, and the lower jaw moves forward, and the upper teeth tilt towards the palatine side. In the lateral areas, due to the separation of the bite, a vertical restructuring occurs, that is, dentoalveolar elongation.

The fundamental clinical and laboratory stages of making a plate differ little from those described in the manufacture of the activator: obtaining impressions, making a wax composition of the plate with retaining and reversible clasps, determining the constructive bite, polymerization of plastic, fitting and application of the device.

It should be remembered that when treating distal occlusion in patients 15-20 years old, when using bite blocks before stabilization occurs, a double or “wandering” bite may be established, that is, in a position of physiological rest, the lower jaw is fixed in a neutral position, and during function it moves to the former (distal).

The devices proposed by R. Fränkel are called functional regulators, the main parts of which are side shields and pelota, which relieve the dentition from the pressure of the cheeks and lips. As a result, under the influence of the tongue, the growth of the apical base is stimulated in the transversal and sagittal directions. The parts of the apparatus are held together by metal arcs made of elastic wire. This skeletonization made it possible to increase the strength of the regulators, reduce the size of the plastic shields, lighten the apparatus and make it open in the frontal area for better swallowing and speech. Active elements (screws or springs) can be added to the device to accelerate the movement of individual teeth.

R. Fränkel proposed function regulators of three main types: type I (FR I) is used to eliminate protrusion of the anterior teeth and distal occlusion, combined with narrowing of the dentition, fan-shaped arrangement of the upper frontal teeth and with anomalies of 1 class. E. Engla; type II (FR II) for the treatment of distal occlusion of subclass 2 (II2), that is, in combination with deep overlap and retrusion of the upper anterior teeth; type III (FR III) for the treatment of progenia. The principal clinical and laboratory stages of the regulators have been described previously.

The use of this method is effective in early childhood (the period of primary and mixed dentition), that is, when one can count on the growth of the jaw bones and especially the apical base. Treatment with the regulator, especially during the period of its development, is recommended according to the following scheme: for the first two weeks use the device during the day for 1 hour, for the next 2 weeks every day for 2 hours, then during all free time, removing the device only during meals; in 2-3 months around the clock. After correcting the bite with adjusters, retention devices are not required, since already during the active phase of orthodontic treatment, the conditions that contribute to the occurrence of relapse are eliminated.

Sagittal movement of the lower jaw during prognathism should be considered as the last stage of treatment, based on the considerations that the restructuring of muscles, temporomandibular joints, as well as dentoalveolar lengthening in the lateral areas in the vertical direction are not always successful. When treating severe forms of prognathia with deep overlap, the separation between the lateral teeth should be at least 45 mm. With active protraction of the lower jaw, tissue restructuring occurs in the order of activation (stimulation) of functional hypertrophy, mainly of the lateral pterygoid muscle, which is poorly developed during prognathism.

It is necessary to constantly monitor the separation of the bite and, as contact between the lateral teeth is achieved, to re-create the separation of the bite by correcting the inclined plane. It is also necessary to correct the appliance in the area where its base adheres to the palatal surfaces of the anterior teeth. In most cases, a sagittally moved mandible is secured in its new position due to the close contacts of natural teeth or contacts created by dentures.

The use of devices can be combined with active myogymnastics, but they are incompatible with edgewise therapy, although it would be very desirable to correct the dentoalveolar components of the anomaly simultaneously with the correction of jaw growth. This is possible when using non-removable functional devices or when combining braces with a facebow. There is no point in drawing a sharp boundary between the phases of treatment, expecting, for example, leveling of the dentition, because extraoral appliances also contribute to a certain extent to the correction of the dental components of the anomaly.

R.G. Alexander is a proponent of the use of extraoral traction in both growing jaws (children, adolescents) and adults. But in the first, with the help of a facial arch, the growth of the upper jaw is suppressed and at the same time its dentition is leveled, the lower jaw is unblocked, providing the opportunity to achieve its genetic potential. In adults, when growth has stopped, the main purpose of extraoral appliances is to hold the upper molars in place, to avoid their displacement forward.

Intermaxillary traction, in the author's opinion, should be used while the dentition of both jaws is aligned and stabilized, rigid end steel archwires are installed (0.17 x 0.25) and torque control is established to prevent incisor tilting. The arches must completely fill the slots of the braces and be in the mouth for at least a month before installing elastic traction according to class II. Having studied the vector of forces in the traditional position of the above-mentioned thrust, that is, from the upper canines to the lower first molars, R.G. Alexander identified the presence of an undesirable, very significant vertical force component. An increase in the horizontal component of the force can be achieved through a different fixation of the traction, namely, from the second lower molar to the spherical hook of the bracket on the upper lateral incisors. This increases the vector of horizontally acting force and reduces the tendency to “open” the bite, for which, by the way, elastics are not used in the “Vari Simplex Discipline” system.

When treating the first subclass (II1) of prognathia, complicated by a deep or open bite, the incorrect position of the teeth and an anomaly in the shape of the dentition are usually eliminated. If it is necessary to expand the lateral areas of the upper dentition, then a rapid palatal expander (rapid maxilla expander) is used in the early stages of treatment, before the installation of fixed appliances. If the teeth have not erupted, then plastic plates with a screw can be used, and only then the lower jaw is moved forward. When treating a distal bite in combination with protrusion of the upper anterior teeth, their close position and narrowing of the dentition or their asymmetry, one should not rush to eliminate the protrusion, since the upper anterior teeth, which have become palatally inclined as a result of treatment, will interfere with the movement of the lower jaw.

According to many clinicians, with early treatment, distal occlusion can be eliminated in approximately 80% of patients with functional devices. The use of edgewise therapy, in particular the direct arch technique, expands the age-related indications for orthodontic correction, but positive dynamics of treatment are observed only at the dentoalveolar level.

In case of distal occlusion (II2), the method of eliminating crowding of teeth must be planned taking into account the structure of the facial skeleton, the age of the patient and the amount of space in the dentition. The correct choice of method allows you to get an optimal result and avoid complications during and after treatment.

Treatment of adult patients comes down mainly to leveling the position of the teeth and eliminating deep incisal overlap, if any. The process of “detailing” the molars is either prolonged (as a result of the “distalization” of first the second and then the first molars) or is impossible because adults already have erupted second and third molars. In such patients, extraction is more indicated, and a dilemma arises: which tooth should be removed, the first or second premolar? To resolve this issue it is necessary to take into account:

the magnitude of the space deficit; if, after straightening the teeth, a residual gap of no more than 2.0 mm is predicted, then the first premolar is removed, and if it is more than 2.0 mm, then the second premolar; this choice can be argued by the fact that during the closure of the spaces between the teeth, the tendency to retrusion of the incisors increases, while the removal of the second premolar has a lesser effect on the position of the incisors;
dental condition, it is preferable to remove the affected teeth (destroyed crown, endodontic treatment, changes in periapical tissues, large filling or severe abrasion);
after extraction, it is necessary to retract the canines or “first premolar canines”, for which the full arch technique or the segmental arch technique can be used;
The full-arch technique in its standard implementation is as follows: at the first stage, braces are fixed on all teeth, using for additional support, for example, a Gozhgarin clasp, when indicated in combination with a face bow; the initial arch, as a rule, is nitinol, with simultaneous “distalization” of the canine or first molar using an eight-shaped ligature (within the dentition this can be done using springs, elastic traction, elastomeric power modules); it should, however, be noted that in this case, a protrusive displacement of the incisors occurs, which is very undesirable in adults, since then it is necessary to retract them to eliminate the sagittal discrepancy, therefore it is better to use the segmental arch technique;
segmental arch technique: braces are fixed only on the teeth of the lateral segment, with additional stabilization of the supporting teeth, as in the previous version; then a steel edge arch with a diameter of 0.40×0.55 mm is passively inserted into the braces; for "distalization" the usual sliding technique; if the canine has an abnormal position initially, then a nitinol arch should first be inserted, fixing it only in braces on the canines and premolars, with simultaneous “distalization” with an 8-shaped ligature; after normalizing the position of the fang, you can move on to a full arch and fixation of braces on the incisors, the leveling of which is carried out according to the traditional method (nitinol arch, steel arches, TMA); This technique allows for canine retraction without side effects on the incisors.

For surgical treatment, write down clear indications:

justification for the need for such therapy, for example, the magnitude of the sagittal discrepancy of the jaws is 10 mm or more, the angle of the SNSs (SNA) on the teleroentgenogram is greater than normal, which is ~ 82°
good state of somatic and mental health, the growth of the patient’s facial skeleton must be complete
pronounced protrusion of the lower incisors (the angle of inclination is less than 70-80°, while the norm is 90-95°); it is well known that the vestibular movement of the lower anterior teeth is very limited and the limit depends on the value of the initial axial angle; the maximum reasonable limit should not be less than 90-95°, therefore, when using equipment for the vestibular movement of the lower front teeth, you need to be very careful; Correction of the sagittal position of the lower anterior teeth can be carried out:
due to changes in their vestibular inclination,
changes in the length of the lower jaw, but this depends on the age and nature of micrognathia, that is, it is of the condylar type (when the articular process, which is the center of longitudinal growth, is affected) or extracondylar,
changes in the position of the mandibular head, if the anomaly has developed due to distal displacement of the mandible
if in skeletal forms of distal occlusion, after correcting the anomaly at the dentoalveolar level (change in the inclination of the upper and/or lower incisors), an acceptable facial profile is achieved, that is, “masking” of the skeletal disproportion occurs, then there is no need for surgical treatment.
The question may also arise about surgical relocation of the lower jaw or about additional surgery in the form of genioplasty (chin correction), if the anomaly cannot be corrected orthodontically, even with tooth extraction
in the preoperative period, existing dentoalveolar discrepancies should be eliminated by orthodontic or orthopedic procedures, carefully studying them, conducting occludography and identifying premature contacts that increase the risk of joint dysfunction in distal occlusion; when planning orthodontic treatment, one should proceed from the installation of the lower jaw in the central relationship, but if there are symptoms of muscle-articular dysfunction, then it is impossible to immediately determine the central relationship of the jaws, and in order to “reprogram” muscle function and muscle relaxation, it is necessary to use occlusal splints before and after orthodontic treatment
with significant underdevelopment of the lower jaw in adult patients, a combination of surgical treatment with prosthetic treatment is possible

An approximate set of myogymnastic exercises for the treatment of distal occlusion. Exercises should be selected according to the child’s age and not be too difficult. L.S. Persia recommends first of all determining the level of development of the child and giving the load not to the point of fatigue, but approximately 75% of it. Exercises to correct a specific anomaly should be dosed and performed against the background of general physical exercise, starting 2-3 weeks before orthodontic treatment.

Muscle contractions must be performed with maximum amplitude, their intensity must be within physiological limits, with a gradual increase in speed and duration; between two successive contractions there should be a pause equal to the duration of the contraction itself.

Exercises to normalize breathing function(performed during morning exercises, physical education lessons or while walking); starting position: the state of correct posture: the head and torso are held straight, the shoulders are slightly pulled back and slightly lowered, the chest is turned out, the shoulder blades are adjacent to the back, the stomach is tucked and the knee joints are straightened.

Exercises to normalize lip closure(can be done during speech development classes). Starting position: sitting in front of a mirror, head held straight, shoulders slightly pulled back and slightly lowered, chest turned out, knee joints bent, legs together, stomach tucked.