Translated from Latin in the dental sense, occlusion means contact between the dentition of the upper and lower jaws at rest. In popular conversation, the term "bite" is used.
At the age of 4 to 6 years, the most active formation of the dentition occurs. Therefore, most occlusion disorders occur during this period. Because of this, it is important to monitor the baby's habits and not let him suck on his fingers and nipple for a long time.
Since it forms in a person incorrect swallowing and push the lower jaw forward. Often developmental abnormalities occur due to diseases of the upper respiratory tract, especially the nasopharynx.
Finally, the dentition completes its formation by the age of 16, therefore, before this age, most defects are much easier to correct. Therefore, it is important to check with the dentist annually for a timely determination and start it on early stage development.
Modern classification
Experts divide occlusion into permanent and temporary. The latter option occurs during active formation 
dentition in the period from 4 to 6 years old, when the child has more than 20 milk teeth.
During this period, the joints and muscles of the jaws gradually adjust to the most advantageous positions. can be classified by developmental anomalies and small deviations in location.
Incorrect bite formation according to the location of the upper row of teeth relative to the lower one is divided into two types - distal and mesial.
Distal occlusion
Open and deep bite
Separately, mention should be made of. This form of abnormal development of the dentition is caused by a physiological factor. In humans, certain groups of teeth do not close.
According to statistics, it occurs in 2% of patients with dentoalveolar problems. Sometimes the problem is associated with mesial or distal occlusion. As well as refers to vertical anomalies in the development of the dentition. The appearance of an open form of the disorder mainly occurs due to diseases of the mother during pregnancy.
To diagnose malocclusion, the patient should contact one of the following specialists:
- dentist;
- orthodontist;
- maxillofacial surgeon;
- dentist therapist.
After the examination, the specialist will choose the most suitable treatment method:
- wearing orthodontic appliances (, screws, etc.);
- surgical correction.
At the reception, the doctor examines the patient and determines the degree of occlusion disorder. As a rule, the patient is fitted with one of the orthodontic structures and then periodically monitored for correct treatment.
The most common and effective method of correction is the installation of bracket systems. Sometimes surgery may be required to correct the dentition.
Improper occlusion impairs human functionality and also causes discomfort due to impaired facial appearance. Therefore, it is important to determine the pathology at the initial stage of development and start its treatment on time.
Definition of the concepts " articulation"And" occlusion "is a big controversy among orthopedic dentists. Some define occlusion as closure, and articulation as articulation and consider these two concepts to be identical. Others define articulation as the relationship of the dentition during mandibular movement, and occlusion as the ratio of the dentition at rest. Thus, these authors consider occlusion to be a static moment and oppose its articulation as dynamic.
It must be admitted, however, that both of these opinions are wrong. Correct definition articulations and occlusion is given by A. Ya. Katz. It includes in the concept of articulation all sorts of positions and movements of the lower jaw in relation to the upper, carried out by means of the chewing muscles. He considers occlusion as a special case of articulation, meaning that the position of the lower jaw in which a smaller or larger part of the articulating teeth are in contact. A.K. Nedergin adheres to the same opinion.
B. N. Bynin defines articulation as the ratio of the dentition during any movements of the lower jaw, and occlusion as the ratio of the dentition during chewing movements. We also find that articulation is a general concept, occlusion is one of the elements of articulation, and we define articulation as the totality of all dynamic and static moments that occur at different positions of the lower jaw, and occlusion as one of the moments of articulation, but not static, but dynamic. Therefore, articulation and occlusion are neither identical nor opposing concepts.
Articulation refers to occlusionsas a whole to a part (articulation is a whole, and occlusion is a part of a whole).
To understand why we attribute occlusion to dynamic, not static moments, it is necessary to point out the following: the locomotor apparatus consists of two parts - active and passive. The musculature is active, the skeleton is passive.
Since every change mandible position in relation to the upper, including the closure, occurs as a result of the work of the musculature, then we must interpret all the moments of articulation, taking into account the state in which the musculature is, and not the bone tissue. With occlusion, the chewing muscles are in working order, since contraction of the muscles is necessary to close the dentition, and, therefore, the occlusion is a dynamic moment. There is only one moment in the position of the lower jaw, which can be called static - this is the so-called state of relative rest.
Distinguish three types of occlusion: front, side and center. Anterior occlusion is the closing of the dentition when the lower jaw is pushed forward, lateral occlusion is the closure of the dentition when the lower jaw moves to the side. As for the central occlusion, it is defined differently by different authors. Some characterize it from the point of view of the position of the articular head in the articular fossa and call the central occlusion such a closure of the dentition, in which the articular head is in the articular fossa and adjoins the posterior surface of the articular tubercle at its base.
Others come from conditions of the chewing muscles and such a closure of the dentition is called central occlusion, in which the greatest contraction of the masticatory muscles proper and the anterior bundles of the temporal muscles is observed. So, DA Entin finds that the usual compression of the jaws (central occlusion) is accompanied by a simultaneous and even contraction of the masticatory and temporal muscles on both sides. Still others determine the central occlusion, based on the nature of the relationship of the dentition during their closing.
In their opinion, central occlusion characterized by multiple contact of the dentition (BN Bynin).
There is finally still determination of central occlusion as the initial and final moment of articulation (M. Müller). This definition will become clear if we recall that Gizi distinguishes four phases in the act of chewing: the first phase comes from the central occlusion, and the fourth ends with the transition of the lower dentition to the initial position, i.e., to the central occlusion.
However, these signs cannot be used in a prosthetics clinic to determine central occlusion, since they require complex research methods. For example, to determine the position of the articular head in the articular fossa, X-ray is necessary, to determine multiple closure, it is necessary to make plaster models of the dentition, etc. The most accessible and practically valuable way to determine central occlusion in the presence of a large number of pairs of antagonizing teeth is the use of signs that are visible by simple eye (N. I. Agapov, A. Ya. Katts, B. N. Bynin, A. K. Nedergin, etc.).
When the lower jaw is extended, the maximum contact of the tubercles of the dentition disappears. This situation is called anterior occlusion(after K.M. Lehmann, E. Helving).
Anterior occlusion is formed when the lower jaw moves forward (Fig. 21)
Figure: 21. Anterior occlusion (Bonneville three-point contact).
In this case, the cutting edges of the anterior teeth of the lower jaw, moving forward, are set "end-to-end" with antagonists in the form of a direct bite. In this case, there is disocclusion of the lateral teeth (or contact of the distal tubercles of the second molars), the articular heads are located opposite the lower third of the posterior slopes of the articular tubercles. In the presence of contacts in the area of \u200b\u200bthe chewing teeth, a three-point Bonneville contact is observed. The presence of a three-point contact ensures the distribution of chewing pressure not only on the anterior group of teeth, but also on the molars.
Lateral occlusion
Lateral occlusion – the closing of the teeth when the lower jaw moves to the side (Fig. 22). Lateral occlusion balancing contacts (according to Gizi). This type of occlusal contact is divided into right and left. They are formed when the lower jaw moves to the sides - to the right or left.
Figure: 22. Lateral occlusion.
With lateral occlusion, the midline is displaced, respectively, towards the lateral displacement of the jaw relative to the midline of the upper jaw. The articular heads are displaced differently. There are three types of occlusal contacts normally observed:
1. The contact of the buccal tubercles of the chewing teeth on the laterotrusion side, the absence of occlusal contacts on the mediotrusion side - the group guiding function of the teeth - group contacts. 2. Canine contacts on the laterotrusion side and the absence of occlusal contacts on the mediotrusive side - canine guiding function - canine protection.
3. Contact of the eponymous cusps of the chewing teeth of the laterotrusion side and the opposite cusps of the chewing teeth of the mediotrusive side - it is recommended to restore occlusion in the absence of teeth.
Posterior occlusion
Posterior occlusion(synonyms: distal, retrouspid, posterior contact position) - when the articular heads of the lower jaw are in the upper, median-sagittal position, which is called the central ratio, then the contacts of the teeth are the posterior occlusion.
Due to the posterior displacement of the lower jaw, posterior occlusion is achieved (observed in 90% of patients), while there is no contact of the tubercles. About 10% of patients cannot move the lower jaw from the bite position. In these cases, the contact of the tubercles and the posterior occlusion are identical. The displacement of the dental arches relative to each other, with significant interdental contacts, from the occlusal position to the remaining positions, is defined as an articulatory movement.
Posterior position of the lower jaw - reproducible physiological position, determined during fixation of the central occlusion and necessary for its determination after the loss of the last pair of teeth - antagonists or the formation of a new structural occlusal height, for example, when hard tissues are erased.
Rear contact position(terminal hinge position of the lower jaw, posterior contact position, retrusive contact position, Centric Relation) - occlusal analogue of the central relation of the jaws - occlusal contacts of the teeth in the position of the central relation of the jaws. With intact dentition, there is a symmetrical contact of the cusps of the chewing teeth. Occlusion in the terminal hinge position of the mandible, in which the articular heads are located in the most extreme upper-posterior position.
Jaw Ratio -position of the lower jaw in relation to the upper.
There are five main types of occlusion: central, anterior, lateral (right and left) and posterior (SL. Pozhar S. 76, Fig. 3.21). Each occlusion is characterized by three features: dental, muscle and articular.
Central occlusion is a type of dentition closure with the maximum number of contacts of antagonist teeth. The head of the lower jaw is at the base of the slope of the articular tubercle, and the muscles (temporal, chewing, medial pterygoid), bringing the lower dentition into contact with the upper one, are simultaneously and evenly contracted. From this position, lateral shifts of the lower jaw are possible. With central occlusion, the lower jaw occupies a central position, while the midpoint of the chin and the incisal line are on the same straight line, and the height of the lower part of the face is proportional to the other two (upper and middle).
Anterior occlusion is characterized by the forward extension of the lower jaw. This is achieved by bilateral contraction of the lateral pterygoid muscles. In orthognathic occlusion, the midline of the face, as in central occlusion, coincides with the midline between the incisors. The heads of the lower jaw are displaced forward and located closer to the apex of the articular tubercles.
Lateral occlusion occurs when the lower jaw is moved to the right (right lateral occlusion) or to the left (left lateral occlusion). The head of the lower jaw, slightly rotating on the side of displacement, remains at the base of the articular tubercle, and on the opposite side it shifts to the apex of the articular tubercle. Lateral occlusion is accompanied by unilateral contraction of the lateral pterygoid muscle of the opposite side.
Posterior occlusion occurs when the mandible is dorsally displaced from a central position. The heads of the lower jaw are displaced distally and upward, the posterior bundles of the temporal muscles are tense. From this position, lateral shifts of the lower jaw are no longer possible. To move the lower jaw to the right or to the left, it is necessary to first move it forward - into the central occlusion. Posterior occlusion is the extreme distal position of the mandible during its sagittal chewing movements.
The state of relative rest of the lower jaw
Most of the mandibular movements start from the central occlusion position. However, outside the function, when the lower jaw does not take part in chewing or talking, it is lowered and a gap of 1 to 6 mm or more appears between the dentition. (SL Abolmas C 17, Fig. 29, 30, 31) This position of the lower jaw is called the state of relative physiological rest. It is characterized by functional rest of all groups of the masticatory muscles and relaxation of the facial muscles. The magnitude of the separation of the dentition at rest of the lower jaw is individual. It increases with age. The state of relative physiological rest of the lower jaw is regarded as a kind of congenital protective reflex, since the constant closing of the teeth would cause ischemia and the development of a dystrophic process in the periodontium and overstrain of the masticatory muscles.
Bite
The nature of the closure of the dentition in the position of the central occlusion is called the bite. There are three groups of bite: physiological, abnormal and pathological (SL Abolmas C 16, Fig. 28)
Physiological bite (normognathic). Physiological bite is considered, in which full-fledged functions of chewing, speech, swallowing and aesthetic optimum are provided. It includes orthognathic, direct, progenic, prognathic, biprognathic.
Orthognathic occlusion is considered to be the most perfect form of closure of the dentition in anatomical and functional terms. Closing of the dentition in the position of central occlusion is considered in three planes: horizontal, sagittal and frontal. All teeth are characterized by the following closure signs.
1. Each tooth contacts two antagonists. The exception is the upper wisdom teeth and the central incisors of the lower jaw, which have one antagonist each.
2. Each tooth of the upper dental arch merges with the lower and behind the one of the same name. This is due to the predominance of the width of the upper central teeth over the lower ones, therefore the lower teeth are displaced medially in relation to the teeth of the upper dentition.
3. The upper wisdom tooth is narrower than the lower one, in this regard, the medial shortening of the lower dentition is aligned in the area of \u200b\u200bthe wisdom teeth and their distal surfaces lie in the same plane.
4. The upper anterior teeth overlap the lower ones by about 1/3 of the crown height.
5. The lower anterior teeth with their cutting edges are in contact with the palatal surface of the upper incisors (cutting-tubercular contact).
6. When the dentition is closed, the lines between the central incisors of the upper and lower jaws coincide and lie in the same sagittal plane. This provides an aesthetic optimum
The features of the closing of the lateral teeth are as follows: the buccal tubercles of the upper molars and premolars are located outward from the similar tubercles of the lower teeth. Due to this, the palatine tubercles of the upper teeth are located in the longitudinal grooves of the lower teeth. The overlap of the lower teeth by the upper teeth is due to the greater width of the upper dental arch. This ratio of the dentition provides freedom and a large range of lateral movements of the lower jaw, expanding the occlusal field.
An important sign of orthognathic bite is the ratio of the first molars of the upper and lower jaws, which is called the "key of occlusion". In this case, the anterior buccal tubercle of the first upper molar is located in the transverse groove between the buccal tubercles of the mandibular molar.
Abnormal bite. Abnormal bites are characterized by disorders of the function of chewing, speech and appearance of a person, i.e. there are not only morphological disorders, but also functional ones. Anomalous bites include distal, mesial, deep, disocclusion in the frontal area (open bite) and crossbite (Sl Pozhar S. 79, Fig. 3.23).
Distal bite is observed with overdevelopment or anterior position of the upper jaw in the facial skeleton, as well as with underdevelopment of the lower jaw or its distal position in the facial skeleton. With distal occlusion, the closure of the front teeth is disrupted: a gap and deep overlap appear between them. The teeth of the upper jaw protrude strongly forward, pushing the upper lip, from under which the cutting edges of the teeth are exposed. The lower lip, on the contrary, sinks, falling under the upper incisors. In the lateral areas of the dentition there is the following ratio: the mesio-buccal cusp of the first upper molar closes with the cusp of the same name of the first lower molar, and sometimes falls into the groove between the second premolar and the mesio-buccal cusp of the first lower molar. The anomaly, as a rule, is accompanied by a violation of aesthetics, chewing and speech functions.
Mesial the bite is characterized by overdevelopment of the lower jaw or its forward displacement, as well as underdevelopment of the upper jaw or its distal position in the facial skeleton. At the same time, the anterior teeth of the mandibular dental arch move forward, overlapping the upper ones of the same name. Violation of the relationship of the lateral teeth is characterized by the following signs. The buccal-mesial tubercle of the upper first molar comes in contact with the distal buccal tubercle of the lower molar of the same name or falls into the groove between the first and second molars. Due to the predominance of the width of the mandibular dental arch over the upper buccal tubercles of the lateral teeth of the lower jaw lie outward and overlap the upper ones of the same name. When mesial occlusion is broken appearance sick.
Deep the bite is characterized by an extreme degree of overlap of the anterior teeth with no incisal tubercle contact. The lateral teeth close, as in the case of orthognathic occlusion, the chewing function and the patient's appearance are impaired.
Disocclusion in the frontal area (open bite) - a bite in which there is no closure of the anterior group of teeth, and sometimes premolars. Dissociation of molars (distal or lateral open bite) is much less common. Lack of contact, the gap between the front teeth disrupt speech, the patient's appearance, and biting off food is transferred to the side teeth.
Cross bite accompanied by such a ratio of the dentition, in which the buccal tubercles of the lateral teeth of the lower jaw are located outward from the same upper or lateral teeth of the mandibular dental arch are displaced to the lingual side.
Abnormal types of bite in some cases (the development of pathological abrasion of teeth, tooth extraction as a result of complications of caries or periodontal disease, trauma to the oral mucosa) can be transformed into a pathological bite, which requires adequate treatment.
Occlusion is the most complete occlusion between the incisal edges or chewing surfaces of teeth, which occurs simultaneously with evenly contracted chewing muscles. This concept also includes dynamic characteristics to determine the work of the muscles of the face and the temporomandibular joint.
Correct occlusion is extremely important for the correct functioning of the entire dentition. It provides the necessary load on the teeth and alveolar processes, eliminates periodontal overload, and is responsible for the correct operation of the temporomandibular joint and all facial muscles. With its anomalies, which are observed in the absence of teeth in a row, periodontal diseases and other functional disorders of the dentition, not only the aesthetics of the face suffers. They can also cause increased tooth wear, joint inflammation, muscle strain, and gastrointestinal disturbances. That is why any dental occlusion anomalies require treatment.
Types of dental occlusion
All movements of the lower jaw are provided by the work of the muscles, which means that the types of occlusion should be described in dynamics. Distinguish between static and dynamic, some researchers also distinguish occlusion at rest, which is determined by closed lips and teeth open a few millimeters. Static occlusion characterizes the position of the jaws when they are habitually compressed relative to each other. Dynamic describes their interaction when moving.
Different sources emphasize different aspects of central occlusion. Some look, first of all, at the location of the mandibular joint, while others consider the state (complete contraction) of the chewing and temporal muscles to be of paramount importance. However, in orthopedics and restorations, when it is important to correctly calculate the ratio of teeth in rows, dentists prefer characteristics that can be assessed visually, without the use of complex devices. We are talking about the maximum area of \u200b\u200bclosure in compliance with the formulas:
- the sagittal central line of the face runs between the anterior incisors of the upper and lower jaw;
- the lower incisors rest on the palatine tubercles of the upper ones, and their crowns overlap by one third;
- the teeth have close contact with two antagonists, except for the third molars and the anterior lower incisors.
A slight extension of the lower jaw forms an anterior occlusion. An imaginary vertical midline separates the anterior upper and lower incisors, which in turn touch the incisal edges.
The upper and lower molars may not close evenly, forming a tubercle contact.
Posterior occlusion is characterized by the movement of the lower jaw towards the occiput.
With lateral occlusion, the sagittal line is torn with a shift to the right or left, the teeth of one, working, side touch the same mounds of their antagonists, while on the other, the balancing one, the opposite ones (upper palatal with lower buccal).
Some characteristics of the occlusal system have genetic causes, while others are developed during the growth process. The hereditary factor can affect the shape, size of the jaws, muscle development, eruption of teeth, and the functional apparatus is formed under the influence of various internal and external factors during the development of the jaws.
Understanding occlusion is very important in restorative and prosthetic work in dentistry so that the function of the chewing apparatus is restored as fully as possible.