Radiographic definition of the angle of the sagittal articular path. Modification of the facial arch
Biomechanics of the lower jaw. Sagittal movements of the lower jaw. Sagittal cutting and articulated path, their characteristics.
Forces compressing teeth, mostly create stresses at the rear sections of the branches. The self-preservation of the living bone under these conditions is to change the position of the branches, i.e. The corner of the jaw should change; This is due to childhood through maturity to old age. Optimal voltage resistance conditions are to change the magnitude of the jaw angle to 60-70 °. These values \u200b\u200bare obtained by changing the "external" corner: between the plane of the basis and the rear edge of the branch.
The total strength of the lower jaw with compression in static conditions is about 400 kgf, less than the strength upper jaw by 20%. This suggests that arbitrary loads when compressing teeth cannot damage the upper jaw, which is rigidly connected with the brain department of the skull. Thus, the lower jaw acts as a natural sensor, "dipstick", allowing the opportunity to spray, destroy the teeth, even break, but only the lower jaw, not allowing the upper damage. These indicators should be taken into account during prosthetics.
One of the characteristics of the compact substance of the bone is the indicator of its microhardness, which is determined by special techniques in various appliances and is 250-356 HV (for brinell). A greater indicator is noted in the field of the sixth tooth, which indicates its special role in the dentition. The microhardness of the compact substance of the lower jaw ranges from 250 to 356 HV in the area of \u200b\u200bthe 6th tooth.
In conclusion, we indicate the general structure of the body. So, the branches of the jaws are not parallel to each other. Their plane above are wider than below. The convergence is about 18 °. In addition, their front edges are closer to each other than the rear almost for centimeter. The basic triangle connecting the peaks of the corners and the symphiz of the jaw is almost equilateral. The right and left side are mirrored are not suitable, but only like. The size ranges and embodiments of the structure are depending on the floor, age, races and individual characteristics.
With sagittal movements, the lower jaw moves forward and backward. Forward, it moves due to a bilateral reduction of the outer wonderful muscles attached to the articular head and bag. The distance that the head and down head can pass is 0.75-1 cm. However, with the chewing act, the articulated path is only 2-3 mm. As for the dental rows, the movement of the lower jaw ahead is prevented by the upper front teeth, overlapping the lower frontal is usually 2-3 mm. This overlap is overcome as follows: the cutting edges of the lower teeth slide on the sky surfaces upper teeth See you with the cutting edges of the upper teeth. Due to the fact that the sky surfaces of the upper teeth are an inclined plane, the lower jaw, moving along this inclined plane, produces simultaneously motion not only forward, but also down, and thus the lower jaw is extended. In the sagittal movements (forward and backward), the same as the vertical, the joint head is rotated and sliding. These movements differ from each other only by the fact that the rotation prevails with vertical movements, and with sagittal - sliding.
in the sagittal movements, movements occur in both joints: in the articular and dental. You can mentally hold the plane in the mesio-distal direction through the roasted bumps of the lower first premolars and the distal bugs of the lower teeth of wisdom (and if there are no last, then through the di-steel bugs of the lower
second molars). This plane in orthopedic dentistry and is called an occlusal, or protethic one.
The sagittal cutting path is the path of movement of the lower cutters along the sky surface of the upper cutters when moving the lower jaw from the central occlusion to the front.
The articulated path is the path of the articular head on the skate tube. The sagittal articular path is the path made by the articular head of the lower jaw when it is displaced forward and down the backy of the articular tubercle.
The sagittal cutting path is the path done by the lower jaws on the sky surface of the upper cutters when the lower jaw moves from the central occlusion to the front.
Articular path
During the extension of the lower jaw ahead, the opening of the upper and lower jaws in the field of indigenous teeth is ensured by the articular way when the lower jaw is extended. It depends on the corner of the bending of the articular tubercle. During lateral movements, the opening of the upper and lower jaws in the field of indigenous teeth on the non-working side is provided by an inoperative articular way. It depends on the corner of the bend of the articular tuberculosis and the angle of inclination of the mesial wall of the articular fox on the non-working side.
Cutting path
The cutting path when extending the lower jaw forward and to the side, makes up the front guide component of its movements and ensures the opening of the rear teeth during these movements. A group working guide feature provides teeth opening on the non-working side during working movements.
Biomichen lower jaws. Transvertal movements of the lower jaw. Transvertal cutting and articulated path, their characteristics.
Biomechanics - Application of the laws of mechanics to living organisms, especially to their locomotor systems. In the dentistry, the biomechanics of the chewing apparatus considers the interaction of the dental rows and the temporal-mandibular joint (ENCH) with the movements of the lower jaw due to the function of chewing muscles Transvertal movementscharacterized by certain changes
occlusal contacts of teeth. Since the lower jaw mixes that right, then to the left, the teeth describe the curves intersecting under a stupid angle. The farther from the artician head, the tooth is, the dull angle.
Significant interest are the changes in the relationship between chewing teeth with side tours of the jaw. In the side movements of the jaws, it is customary to distinguish between the two sides: working and balancing. On the working side, the teeth are installed against each other with the same fees, and on the balancing side with variemen, i.e., the roasted lower bumps are installed against the sky.
The transversal movement is therefore not a simple, but a complex phenomenon. As a result of the integrated action of chewing muscles, both heads can simultaneously advance forward or backward, but never happens so that one moves forward, and the position of the other remained unchanged in the articular fossa. Therefore, an imaginary center around which the head is moving on the balancing side, it is in reality is never in the head on the work side, and is always located between both heads or outside the heads, i.e. there is, according to some authors, functional, and not anatomical center .
These are the changes in the position of the articular head during the transverted movement of the lower jaw in the joint. With transverted movements, changes occur in relationships between the dentitions: the lower jaw is alternately moved to one, then in the other direction. As a result, curves arise, which, intersecting, form corners. The imaginary angle formed when the central cutters is moved is called a gothic angle, or an angle of the transvertsal incision.
It is on average equal to 120 °. Simultaneously with this, due to the movement of the lower jaw towards the work side, changes occur in the relationship of chewing teeth.
On the balancing side there is a closure of multi-leaf bucks (the lower peels are closed with the upper pacifications), and on the working side - the closure of every sulfur bumps (pebble - with pebous and paternal - with sky).
Transvertal articular path- The path of the articular head of the balancing side inside and down.
The angle of the transvertsal joint (the angle of the bennett) is an angle projected on the horizontal plane between the purely front and maximum side movements of the articular head of the balancing side (the average value of 17 °).
Bennett movement- Side Movement of the Lower Jaw. The articulated head of the working side is shifting laterally (outward). The articular head of the balancing side at the very beginning of the movement can make a transverse movement inward (by 1-3 mm) - "Initial side
movement "(Immediate sideshift), and then - move down, inside and forward. In others
cases at the beginning of the Bennett movement immediately moves down, inside and forward (Progressive SideShift).
Cutting guides in the sagittal and transvertal movements of the lower jaw.
Transvertal cutting path- The path of the lower cutters on the sky surface of the upper cutters when the lower jaw moves from the central occlusion into the side.
The angle between the transversal incisive ways to the right and left (the average value is 110 °).
Algorithm for constructing a protethic plane with a non-fixed inter-vololar height on the example of a patient with a complete loss of teeth. Making wax bases with bite rollers. Methods of manufacturing wax bases with bite rollers with a toothless jaws, name the sizes of bite rollers (height and width) in the front and side dial on the top and lower jaw.
Determination of the occlusal height of the lower third of the face.
With sagittal movements The lower jaw moves forward and backward. Forward, it moves due to a bilateral reduction of the outer wonderful muscles attached to the articular head and bag. The distance that the head and down head can pass is 0.75-1 cm. However, with the chewing act, the articulated path is only 2-3 mm. As for the dental rows, the movement of the lower jaw ahead is prevented by the upper front teeth, overlapping the lower frontal is usually 2-3 mm.
This is the overlap overcome As follows: the cutting edges of the lower teeth slide on the sky surfaces of the upper teeth before meeting them with the cutting edges of the upper teeth. Due to the fact that the sky surfaces of the upper teeth are an inclined plane, the lower jaw, moving along this inclined plane, produces simultaneously motion not only forward, but also down, and thus the lower jaw is extended.
With sagittal movements (Forward and backward), as well as during the vertical, rotation and sliding of the articular head occurs. These movements differ from each other only by the fact that the rotation prevails with vertical movements, and with sagittal - sliding.
Motion in front Back occurs due to the reduction of lowering and the rear share of the temporal muscles. As a result of this work, the muscles, the articular head makes the return route from the extended position to the original, i.e. in the state of the central occlusion. Motion on the front back is sometimes possible when the articular head is moved from the state of the central occlusion back.
it traffic It occurs as a result of the thrust of lowers and horizontal beams of the temporal muscle, it is very insignificant, possibly within 1-2 mm and is observed mainly in the old people due to the breakdown of the elements of the joint. In the area of \u200b\u200bthe teeth, the movement of back is as follows: the lower teeth slide on the sky surfaces of the upper front teeth up and the stop and come, thus, at the initial position.
In this way, with sagittal movements Moves occur in both joints: in the articular and dental. You can mentally hold the plane in the mesio-distal direction through the roasted bumps of the lower first premolars and the distal bugs of the lower teeth of wisdom (and if there are no lasts, then through the di-steel buggers of the lower second molars). This plane in orthopedic dentistry and is called an occlusal, or protethic one.
If mentally spent Another line on the articular tuberculosis and continue it to intersee with an occlusive plane, then an imaginary angle of the sagittal articular path is formed. This path of U. different people Strictly individual and equal average 33 °.
With thought conduct vertical line on the sky surface of the top front tooth And the continuation of it to intersee with the occlusal plane is formed an imaginary angle of the sagittal incisive path. It is on average equal to 40 °. The magnitution of the corners of the sagittal articular and the incisive paths determines the slope of the articular tuberca and the depth of the overlapping by the lower frontal teeth of the lower.
Transvertal movements.
For transverted movements There are also movements in the temporal and dental joints, various on different sides: on the side where the muscle is reduced, and on the opposite side. The first is called balancing, the second - working. The transverse movement occurs due to the reduction of the outer wonderful muscle on the balancing side.
Fixed Point Attaching the outer wing mucus is located ahead and knutrice from the moving point. In addition, the articular tubercle is an inclined plane. With one-sided reduction in the outer wingid muscle, the articular head on the balancing side moves along the articular tuberculosis forward, down and inside. When moving the joint head inside, the direction of the new head path forms with the direction of the sagittal path an angle equal to an average of 15-17 ° (Angle beta).
On workers side articular head, almost without leaving the articular fossa, rotates around its vertical axis. In this case, the articular head on the working side is the center around which the head is rotated on the balancing side, and the lower jaw moves therefore not only forward, but also in the opposite direction.
All said only schematically Pictures a transvertsal movement. This provision is not observed in. reality in the following reasons: The outer wonderland muscle does not act in isolated, because in any movement there is a complex effect of all chewing muscles, which is as follows. With lateral movements, even before cutting the agonist - the outer wing like muscle - the outer wardlike muscle on the working side begins to shrink on the balancing side, and then after entering the action, it gradually relaxes and tightening again, slows down moving the lower jaw and gives the action of agonist clarity and smoothness.
But bilateral abbreviation outdoor wonderful muscles Causes the lower jaw nomination. This movement is hampered by the effect of cutting lowering. The reduction of the latter could cause lower jaws, but their work is hampered by the revealed raising.
Transverse movement Therefore, it is not a simple, but a complex phenomenon. As a result of the integrated action of chewing muscles, both heads can simultaneously advance forward or backward, but never happens so that one moves forward, and the position of the other remained unchanged in the articular fossa. Therefore, an imaginary center around which the head is moving on the balancing side, it is in reality is never in the head on the work side, and is always located between both heads or outside the heads, i.e. there is, according to some authors, functional, and not anatomical center .
These are the changes the positions of the articular head With the transverted movement of the lower jaw in the joint. With transverted movements, changes occur in relationships between the dentitions: the lower jaw is alternately moved to one, then in the other direction. As a result, curves arise, which, intersecting, form corners. The imaginary angle formed when the central cutters is moved is called a gothic angle, or an angle of the transvertsal incision.
It is on average equal to 120 °. At the same time as a result move the lower jaw In the direction of the work side, changes occur in the relationship of chewing teeth. On the balancing side there is a closure of multi-leaf bucks (the lower peels are closed with the upper pacifications), and on the working side - the closure of every sulfur bumps (pebble - with pebous and paternal - with sky).
A. Ya. Katz. correctly disputes this position and on the basis of its clinical studies It proves that the closure of the buggers occurs only on the working side, and only between the roasting strums. As for the rest of the bugs, the lower bugs of the lower teeth are installed on the balancing side against the sky buggers of the upper teeth, not closing, and only peeled bugars are closed on the working side, there is no closure between the pagan strursions.
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Axiograph - Device for recording the movements of the lower jaw and the determination of the articular angles.
Axiography - Method of finding a hinge axis, record movements of the lower jaw and the determination of the joint corners.
Articulator - Device for imitation of lower jaw movements. It can be configured by middle data (medium-medal articulator) or individual values \u200b\u200bof articular and cutting pathways, which are determined by axiography (fully adjustable articulator) or at biting blocks (refractory wax, a-silicone), fixing the front and side occlusion (semi-regulated articulator ).
Burki teeth
Neopher tubercles - Budgorki teeth who direct the side movements of the lower jaw: the pebble tubercles of the upper and the paternal - the lower side teeth. Synonyms: guide tubercles, protective tubercles (protect the cheeks and the language from entering them between the teeth).
Supporting tubercles - Budgorka teeth, which in central occlusion retain the vertical ratios of the jaws (sky bumps of the upper and penetrated - lower side teeth).
Horizontal - Anthropometric Landmarks
Kamper horizontal - The novel line from the middle of the ear goat to the outer edge of the wing of the nose (on the skull from the lower edge of the bone of the exterior auditory passage to the front of the nasal asset.
Frankfurt horizontal - Line running from the lower edge of the orbit to the top edge of the external auditory passage.
Movement of the lower jaw
Active movements are carried out by the patient, passive - are sent by a doctor.
Bennett movement - Side Movement of the Lower Jaw. The articulated head of the working side is shifting laterally (outward). This movement can be combined with movements forward, backward, down and up. The articulated head of the non-working (balancing) side at the very beginning of the movement can perform a transversal movement inside (by 0.5-1 mm) - "Initial Side Shift" (Immediate Side Shift), and then down, inside and forward. In other cases, at the beginning of the movement of Bennett, there is no "initial lateral movement" inside and immediately moves down, inward and forward progressive lateral movement (Progressive Side Shift).
Chart of Asselta(Posselt U.) is the designation of the border movements of the lower jaw in the sagittal plane on the movement of the cutting point.
Laterotrusia is the movement of the lower jaw, at which its deviation occurs from the median-sagittal plane of the dust. Laterotrusion side - working side with lateral occlusion.
Medioterusia - The movement of the lower jaw, at which its deviation occurs to the median and sagittal plane. The medioterous side is an inoperative, balancing side with lateral occlusion.
Prudrunza - The movement of the lower jaw, in which both artic heads are simultaneously shifted down and forward, and between the side teeth, a triangular slot is formed, which decreases (the phenomenon of Christensen). Such a slot is formed between the occlusal rollers in determining the central ratio of toothless jaws, if the lower jaw is shifted forward. The coolest of the backy of the articular tubercle, the more gap, and vice versa. This phenomenon is used to determine the corners of the articular paths with bicycle blocks.
"Sliding in the center" - the movement of the lower jaw from the central occlusion to the central relationship of the jaws (in the rear contact position) in the presence of symmetrical bilateral occlusal contacts of the boards of the chewing teeth (Slide in Centric).
Ways of movement of the joint heads
Side articular way - The path of movement of the articular head balancing (medioterzion) side inside, down and forth.
Sagittal articular path - The path of movement of the joint heads down and forth along the rear skates of the articular tubercles when moving the lower jaw from the central to the front occluding.
Ways to move the lower cutters
Side cutting path - The path of movement of the lower cutters on the sky surface of the upper cutters with the lateral movements of the lower jaw from the central occlusion.
Sagittal cutting path - The path of movement of the lower cutters on the sky surface of the upper cutters when moving the lower jaw from the central occlusion to the front.
Powl Line - Imaginary line from the mesial edge of the lower fang to the inner (paternal) edge of the mandibular tubercle. Artificial teeth of the removable prosthesis for toothless jaws should not go for this line.
Facial arc - A device for installing jaw models into an article.
Occlusion - Any contact of the tooth of the upper and lower jaws.
Side occlusion. There are three types of occlusal contacts observed normally:
1) contact of the chewing teeth of chewing tubes on the laaterozion side, the lack of occlusive contacts on the medioterusion side - the "group guide function" of the teeth, "group contacts";
2) Contacts of fangs on the laaterotrusion side and the absence of occlusal contacts on the medioterusion side - the "fanging guide function", "string protection", occlusion, "protected by fangs". These two types of occlusal contacts are recommended when the occlusion is restored in the presence of teeth;
3) the contact of the stunning bugger bugger teeth of the laaterozion side and the multi-dimensional windows of the medioterusion side. This type of occlusive contacts is recommended when the occlusion is restored with the complete absence of teeth.
Bilateral balanced occlusion - With all the movements of the lower jaw there is contact of the side (right and left) teeth. This concept is adopted for prosthetics toothless jaws, as it provides stabilization of prostheses. In case of intact dental rows, such an occlusion is a risk factor for the pathology of solid teeth and chewing muscular tissues (dental span, hyperactivity of chewing muscles, bruxism, etc.).
"Lingucked" occlusion is offered by a number of authors for the production of artificial teeth removable Prostheses With the complete absence of teeth, as well as to create occlusal contacts in the manufacture of prostheses on the implan tatoms. At the same time, the contact of the sky tubercles of the upper molars and the second premolars with the holes of the lower same named teeth on the principle of "pestle in mortar", the remaining tubercles of these teeth do not have contact with antagonists. Thus, the occlusive contacts are shifted into the pagan side, which, according to the authors, ensures unhindered side shifts of chewing jaws, distributes chewing pressure in the center of the alveolar process, improves the stabilization of removable prostheses with the complete absence of teeth.
Unacceptable occlusion - deviations from normal occlusion are accompanied by periodone pathology, chewing muscles and ENCH. Exclusional correction is shown.
The front occlusion is the contact of the front teeth "Jack", in which there is a sidelion of the side teeth, the articular heads are located opposite the lower third of the rear skates of the joint tubercles.
Acceptable occlusion- occlusion at which there are deviations from the "occlusal norm", there are no dysfunctional disorders. Such an occlusion is aesthetically satisfied with the patient and does not require change.
The usual "occlusion - Forced occlusion at the maximum possible contact of the existing teeth. Characteristically violation of the topography of the elements of the EMEDs (offset of the joint heads and / or disks). Perhaps the presence of symptoms of muscular-articular dysfunction.
« Free central occlusion"- occlusion at which the lower jaw offset is possible in the limits of 1-2 mm in all directions from the position of central occlusion while maintaining bilateral occlusion contacts of the boards of the chewing teeth (Freedom In CENTRIC).
Stable occlusion- Provided by the contact of the support tubercles (the upper palatine, lower peeles) in fissuras and edge numerals of opposite teeth, in contrast to the unstable occlusion, at which there is a contact of the vertices or hollows of tubercles of opposite teeth.
Functional occlusion (articulation) - dynamic contacts of dental rows during chewing - the result of the integrated function of all units of the dental-facial system.
Central occlusion - multiple fesur-tuberculous contacts of dental rows, under which the artic heads are located in the thinnest avascular part of the joint discs in the front of the articular sinks opposite the base of the joint tuberculos, the chewing muscles are simultaneously reduced. The ratio of dental rows during jaws is closed in central occlusion - bite.
Central occlusion - term combining central occlusion, sliding in the center and rear contact position of the teeth in the central relationship of the jaws.
"Eccentric occlusion" - occlusive contacts of teeth in the front and lateral occlusion with the chewing movements of the lower jaw.
Occlusal plane - a plane that can be determined by an intact dental row between the following three points: the median contact point of the cutting edges of the lower central cutters and the vertices of the distal-penette tubercles of the second lower molars on the right and left; corresponds to Kamper horizontal.
Balancing (non-working) contacts - Contacts of the teeth of the medicine-trusion side, which are not preventing the contacts of the dental of the laaterotrusion side.
Hyperbalancing Contacts - Supercontacts of the teeth of the medioterous side, preventing occlusive contacts of the dental dentions of the laaterozion side (internal rocks of the bearing tuberculos of chewing teeth). Often the cause of muscular and articular dysfunction.
Workers supercontacts - Contacts of the Laterotrusion side teeth on the rods of the same name tubercles of premolars and molars that prevent closure of fangs on the working side.
Supercontacts - unwanted occlusive contacts that prevent the proper closure of teeth in central, front, side occlusion and in the central ratio of jaws. In accordance with this, they are divided into centric, eccentric, on the working, on the balancing side, in front occlusion. Synonyms: occlusal interference, premature contact, occlusion-zyon obstacle.
Centricular supercontact - Supercontact in centric occlusion.
Eccentric supercontact - Supercontact in eccentric occlusion.
Occlusional curves
Sagittal occlusive curve (spea curve) - passes through the vertices of tubercles of the lower jaw teeth, the most deep point Located on the first molar.
Transversal occlusal curve (wilson Curve) - passes through the vertices of tubercles of the lower jaw teeth in the transverse direction.
« Occlusive compass» (« functional corner") - Ways to move the supporting tubercles in the respective fissuras and edges of opposite teeth when moving from central occlusion to the front and side occlusion.
The axis of rotation of the lower jaw
Vertical axis - The conditional vertical line passing through the articular head of the working side, around which the lower jaw is rotated in the horizontal plane with lateral movements.
Sagittal axis - The conditional sagittal line passing through the articular head of the working side, around which the lower jaw rotates in the frontal plane with lateral movements.
Hinge axis- The conditional transversal line connecting both articular heads, which is fixed when opening and closing the mouth by 12 mm. At the same time, the joint heads are located symmetrically in the center of the articular pits, and the jaws in the central ratio.
Each axis of rotation is perpendicular to two others.
Positions of the Lower Jaw
"Therapeutic" position of the lower jaw It does not always coincide with the position of the lower jaw in the central occlusion. It is installed, for example, using an occlusal tire for disagreening the dental rows and removing excessive loads with the ONSH with the front dislocation of the disc, the distal displacement of the joint heads.
Lower jaw position in the "rear contact position" - Used when determining the hinge axis of the joint heads. In this position, there is a symmetrical contact of the slopes of tubercles of opposite teeth and the gap between the front teeth.
Lower jaw position in central occlusion It is characterized by the physiological position of the joint heads in the articular holes: without lateral displacements with the right mutual arrangement of heads and disks.
Lower jaw position with maximum closure of dental rows due to occlusal factors. Often in this case, the joint heads do not occupy proper position In the articular pits (forced, familiar occlusion).
Position of the lower jaw in physiological peace - Disadvantage of dental rows from 2 to 6 mm with a head position of the head. This position of the lower jaw depends on many factors (psycho-emotional state, medication reception).
Central position of heads- The position of the articular heads, in which the front, upper and rear-joint slits are approximately the same among themselves, as well as on the left.
Central Ratio of Jaws- the arrangement of the jaws in three mutually perpendicular planes, in which the artic heads are in the upperweed median-sagittal position in the articular holes, from which the lower jaw can freely perform lateral movements, and when opening and closing the mouth, within 12 mm between central cutters can freely rotate Around the terminal hinge axis passing through the artic heads. This is the only position of the lower jaw, which can be reproduced multiple times, it is limited by the anatomical form of the ENCH, its ligaments, and the central occlusion is stabilized by occlusal contacts of the side teeth. Synonyms: Terminal hinged position of the lower jaw, Centric Relation.
Middle-sagittal plane - a vertical plane that passes through the front point formed by the intersection of a palate with a second transverse sky fold (between fangs), and through the rear point located on the boundary of the solid and soft sky.
Triangle Bonville- Equipical triangle between the median coil point of the lower central cutters and the centers of the articular heads.
Corners for installing models in the articulator articulator and settings to the individual function of the dental-facial system
Balquilly angle - The angle between the line connecting the articular head (upper surface) and the median point of the incisors, on the one hand, the Kamper horizontal, on the other. Equal to 22-27 °. It matters to find the occlusal plane, setting the models into the articulator.
The angle of the side - The angle between the side incisive ways to the right and left (according to A.Gizya is -110 °).
The angle of the side of the articulation (the angle of Bennett.) - an angle projected on the horizontal plane between the front and side movements of the articular head of the balancing side (according to A.Gizya is -18 °).
The angle of the sagittal incisive - The angle of inclination of the sagittal incitement to the Kamper horizontal (according to A.Giza is -60 °).
The angle of the sagittal articulation - The angle of inclination of the sagittal articular path to the Kamper horizontal (according to A.Giza is -30 °).
Fisher's corner - between the front and medioterzion paths of the articular head movement in the projection on the median-sagittal plane (determined on axiog-ramma). None in the norm. It is observed with disorders in the joint, for example, when the discharge disk is dislocation and inside.
Funogram - recording of the movements of the lower jaw with the help of a function.
Kleinrock function (Ivoclar, Germany) is an intraperary device for registration of lower jaw movements in a horizontal plane with intact dental rows and partial absence of teeth. It consists of a horizontal plate, which is located on the lower jaw, and the set of pins (rigid and spring) - on the upper jaw. Hard (reference) pins when disagreened with dental rows record the Gothic (sweat-shaped) angle between the movements of the lower jaw to the right and left (the vertex of the gothic angle is the central ratio of the jaws), the movement of the lower jaw forward. The spring pin with the contact of the dental rows is recorded: a gothic arc from the position of the central occlusion (or the central relationship of the jaws) into the right and left side occlusion (this entry characterizes the movement of the lower jaw due to occlusal contacts), an occlusive field - a field of all kinds of occlusal movements of the lower jaw.
To determine the central relationship of the jaws and the record of the Gothic angle with the complete absence of teeth, the centrchix ("Girrbach", Germany), a pantometer (Ivoclar, Germany) are used.
Yatrogenic disorders of occlusion - Disorders of centric and eccentric occlusion as a result of manufacturing tabs, various orthopedic structures and conducting orthodontic reconstructions.
Overbite. - Vertical overlap of the incisors.
Overjet. - Sagittal gap between the cutters.
Set Up.- A method in which gypsum jaw models are cut horizontally along the alveolar process and vertically between the teeth so that the teeth can be moved in accordance with the norm, to secure them in the new position and study the functional occlusion in the articulator, and then make an orthodontic treatment plan.
Wax Up. - Test wax modeling of teeth in the articulator used to diagnose and draw up a patient plan.
V.A. Chatovova
Clinical ratology
Lower jaw biomechanics It should be considered from the point of view of the functions of the dental system: chewing, swallowing, speech, etc. The movements of the lower jaw occur as a result of the complex interaction of chewing muscles, ENCH and teeth, coordinated and controlled CNS. The reflex and arbitrary movements of the lower jaw are regulated by the neuromuscular machine and are carried out in series. Initial movements, such as biting and placing a piece of food in the mouth, arbitrary. Subsequent rhythmic chewing and swallowing occur unconsciously. The lower jaw performs movements in three directions: vertical, sagittal and transvertal. Any movement of the lower jaw occurs while sliding and rotating its heads.
Scheme of translational movements of the lower jaw heads and down
The ENCH provides a distal fixed position of the lower jaw relative to the top and creates the guide planes for its movement forward, on the side and down within the limits of the movement boundaries. In the absence of contact between the teeth, the movement of the lower jaw is directed by the articulating surfaces of the joints and proprigative neuromuscular mechanisms. The stable vertical and distal interaction of the lower jaw with the top is provided by the integrabright contact of the toothagonists. Tooth tubercles also form guide planes for the movement of the lower jaw ahead and to the side within the contacts between the teeth. When the lower jaw moves, and the teeth are in contact, the chewing surfaces of the teeth are guided by movement, and the joints play a passive role.
Vertical movements characterizing the opening of the mouth are carried out with an active bilateral reduction in muscles coming from the lower jaw to the sub-band bone, as well as by the severity of the jaw itself.
Movement of the lower jaw when opening the mouth
In the opening of the mouth, three phases are distinguished: a slight, significant, maximum. The amplitude of the vertical movement of the lower jaw is 4-5 cm. When closing the mouth, the rise of the lower jaw is carried out by simultaneously cutting the muscles raising the lower jaw. At the same time, the head of the lower jaw heads are rotated along with the disk around their own axis, then down and forth on the skate tube to the vertices when opening the mouth and in the reverse order when closing.
Sagittal movements of the lower jaw characterize the extension of the lower jaw forward, i.e. The complex of movements in the sagittal plane within the boundaries of the movement of the interlict point.
The movement of the lower jaw forward is carried out by a bilateral reduction in lateral wing like muscles, partially temporal and medial wing muscles. The movement of the head of the lower jaw can be divided into two phases. In the first disk, along with the head slides on the surface of the articular tubercle. In the second phase, a hinged movement of it is joined to slip it around its own transverse axis passing through the heads. The distance that the head of the lower jaw passes when it moves forward, is the name of the sagittal articular path. It is an average equal to 7-10 mm. An angle formed by the suspension of the line of the sagittal articular path with an occlusional plane is called an angle of the sagittal articular path. Depending on the degree of severity of the articular tuberculosis and tubercles of the side teeth, this angle is changing, but on average (according to Giz) is 33 °.
Biomechanics of the lower jaw when moving from central occlusion to the front:
O-O1 - Sagittal articular path, M-M1 - Sagittal Path of Molary, R-P1 - Sagittal Cutting Road; 1 - The angle of the sagittal articular path, 2 - the angle of the sagittal incitement, 3 - disassemble (disassembly between molars)
Sagittal occlusive curve (SPEE curve) It takes place from the upper third of the distal slope of the lower fang to the distal lumpy tubercle of the last lower molar.
When the lower jaw is extended, due to the presence of a sagittal occlusive curve, multiple interdental contacts arise that ensure harmonious occlusive relations between the dentitions. The sagittal occlusive curve compensates for the irregularities of the occlusal surfaces of the teeth and therefore is called a compensatory curve. Simplified mechanism of movement of the lower jaw is as follows: when moving forward, the head of the mumane process moves forward and down the screen of the articular tuberca, while the lower jaw teeth are also moving forward and down. However, meeting with a complex terrain of the occlusal surface of the upper teeth, form a continuous contact with them until the dentition disunity occurs due to the height of the central incisors. It should be noted that under the sagittal movement, the central lower cutters slide through the root surface of the upper, passing the sagittal cutting path. An angle formed by a vector of the incisor and an occlusal plane. Depending on the elevation of the central cutters tubercles, this angle is changed, but on average is 40-50 °. Thus, the harmonious interaction between the buccorks of chewing teeth, the rubber and articulated ways ensures the preservation of teeth contacts when the lower jaw is extended. If you do not take into account the curvature of the sagittal compensatory occlusive curve in the manufacture of removable and non-removable prostheses, there is an overloading of the articular disks, which will inevitably lead to the disease of the ENCH.
The ratio of sagittal articular and sagittal incisive ways
Transvertal (side) lower jaw movements They are carried out as a result of preferably one-sided reduction in the lateral wing like muscle. When the lower jaw moves, the left lateral walled muscle is reduced and the opposite. In this case, the head of the lower jaw on the working side (the offset side) rotates around the vertical axis. On the opposite balancing side (the side of the reduced muscle), the head of the lower jaw slides along with the disc on the articular surface of the tubercle down, forward and somewhat inside, making the side articular path. The angle formed between the lines of the sagittal and transvertsal articular path is called the angle of the transvertsal articular path. In the literature, he is known as " corner Benneta"And equal, on average, 17 °. Transversal movements are characterized by certain changes in the teeth position. The curves of the lateral movements of the front teeth in the intergrole point are intersect under a stupid angle. This angle is called a gothic or angle of the transverts. It determines the scope of the cutters in the lateral movements of the lower jaw and is equal to an average of 100-110 °.
Lower jaw movements (Gothic angle - 110 ° and the angle of Benneta - 17 °)
These data is necessary for programming the articular mechanisms of devices that imitate the movement of the lower jaw. On the work side, the side teeth are set relative to each other with the same bumps, on the balancing side of the teeth are in an open state.
The nature of the closure of chewing teeth at the left side occlusion: a - balancing and used working side
It is known that chewing teeth The upper jaws have the tilt of the axis in the peel, and the lower teeth are in the pagan. Thus, a transverse occlusion curve is formed connecting the chewing teeth of the sides with the same side of the sides of the other side with the same side.
In literature transvertal occlusal curve It occurs under the name of the Wilson curve and has a radius of curvature of 95 mm. As noted above, with the side movements of the lower jaw, the microchochy process on the balancing side moves forward, down and inward, while changing the plane of the jaw tilt. In this case, the antagonist teeth are in continuous contact, the blurring of the dentition occurs only at the moment of contact of the fangs. This type of opening is called "canine maintenance". If at the time of the opening of molars on the working side in contact remains fangs and premolars, such a type of opening is called "canine-premolar maintenance". In the manufacture of fixed prostheses, it is necessary to establish which type of opening is characteristic of this patient. This can be done, focusing on the opposite direction and to the height of the fangs. If this is not possible, it is necessary to make a prosthesis with a fangovo-premolar leading. Thus, it is possible to avoid overloading of periodontal tissues and articular disks. Compliance with the radius of curvature of a transverzal occlusive curve will help to avoid the emergence of supercontacts in the chewing group of teeth with the lateral movements of the lower jaw.
The central ratio of the jaws is the starting point of all the movements of the lower jaw and is characterized by the topmost position of the joint heads and the tuberculk contact of the side teeth.
Opening of the mouth (a) from the position of the central relation (b) and the central occlusion (B)
The slip of the teeth (within 1 mm) from the position of the central relation to the central occlusion is directed forward and upward in the sagittal plane, it is otherwise called the "sliding in the center".
Lower jaw movement from the central relation (A) to the central occlusion (b)
When the teeth are closed in the central occlusion, the injective tubercles of the upper teeth are in contact with central pits or edge protrusions of the lower molars and premolars. The roasting tubercles of the lower teeth are in contact with the central pits or edge protrusions of the same upper molars and premolars. The roasting tubercles of the lower teeth and the roasting tops are called "reference" or "retention", the paternal tubing tubercles of the lower and penetrating tubercles of the upper teeth are called "guides" or "protective" (protect the tongue or cheek from oxidation).
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Functional assignment of tubercles:
1 - brushing tuberculosis of the upper molar - protective;
2 - Network tuberculosis of the upper molar - support;
3 - Sliding tube of the lower molar - protective;
4 - Paluinal Budrock of the Lower Molary - Protective
When the teeth are closed in the central occlusion, the injective tubercles of the upper teeth are in contact with central pits or edge protrusions of the lower molars and premolars. The roasting tubercles of the lower teeth are in contact with the central pits or edge protrusions of the same upper molars and premolars. The roasting tubercles of the lower teeth and the roasting tops are called "reference" or "retention", the paternal tubing tubercles of the lower and peeled bugs of the upper teeth are called "guides" or "protective" (protect the tongue or oxide cheek).
The percentage of support and guide tubercles
In case of chewing movements, the lower jaw should be unhindered to slide on the occlusal surface of the tooth of the upper jaw, i.e. The tubercles should slightly slide along the antagonist teeth, not disturbing an occlusive relationship. At the same time, they must be in dense contact. On the occlusal surface of the first lower molars, the sagittal and transverzal movements of the lower jaw are reflected by the location of the longitudinal and transverse fissures, which got the name " occlusive compass" This benchmark is very important when modeling the occlusal surface of the teeth.
Occlusive compass:
a, C - sagittal movements; b, e - transvertsal movements; D - Combined Movement
When the lower jaw moves forward the guards of the chewing teeth of the upper jaw glide along the central fissure of the lower teeth. With lateral movements, the sliding occurs on a fissure, separating the posterior and median brush tuberculor of the lower molar. In case of combined motion, the sliding occurs on a diagonal fissure separating the middle brush tuber. " Occlusive compass»Observed on all the teeth of the side group.
An important factor in biomechanics of the dental system is the height of the chewing teeth tubercles. The magnitude of the initial joint shift depends on this parameter. The fact is that with the lateral movements of the lower jaw head on the working side, before starting the rotational movement, the duck is shifted, and the head on the balancing side is shifted inside. Such a movement is carried out within 0-2 mm.
Primary articular shift
The more flat ridges of tubercles, the larger the initial articular shift. Thus, the free mobility of dentitions relative to each other within the central occlusion is determined. Consequently, when modeling artificial teeth it is imperative to observe the parameters of the tubercles and the slopes of the beams of chewing teeth. Otherwise, violations occur in the interaction of ENCH elements, articular dysfunction is developing.
Summing up, it is important to note that in the manufacture of a full-fledged functional prosthesis it is necessary to take into account five fundamental factors that determine the features of the articulation of the lower jaw:
1) the angle of inclination of the sagittal articular path;
2) height of chewing teeth huts;
3) sagittal occlusive curve;
4) the angle of inclination of the sagittal incitement;
5) transvertsal occlusive curve.
In the literature, these factors are known as the "five Ghana", by the name of an outstanding scientist who has established this pattern.
With prosthetics of large and complete dental defects, with a generalized form of pathological washes, it is necessary to create dentitions with a strictly individual occlusal curvature, corresponding to the corner of the sagittal articular path. According to the theory of GYSI and HANAU, multiple contacts between the toothed rows of the upper and lower jaws in the chewing movement phase are possible only under the condition of their correspondence and the shape of the articular tubercle. HANAU highlights 5 factors of the so-called articulation of the top (Articulations Guint): 1) the tilt of the articular path; 2) the depth of the compensation arc; 3) the slope of the protethic plane; 4) the slope of the upper incisors; 5) the height of the buggers of artificial teeth - which may change. These factors and up to this day are of great importance. A. Gerber draws attention to the fact that the chewing surface of the cutting constant dental teeth is generated gradually, having gripped during the functioning and acquiring the "articular" form to work in harmony with jaw joints.
To determine the angle of the sagittal articular path, the graphic recording of the lower jaw movement is traditionally applied using the facial arc extraoral. To fix the front arc on the lower jaw, the doctor mounts a portable plate on the wax roller of the lower bite template. The portable plate is designed so that the two mounting pins protrude from the oral cavity (Fig. 1). On these pins, the face arc is attached and fixed. The doctor defines in the patient its side articular points (external auditory passages) and fixes the hinge axis. At these points of fixation, writing tips are configured (Fig. 2). Registration cards for which the schedule is applied is set between points of fixation and writing tips. While moving up and down the lower jaw writing tips record the path of the joints. The angle of inclination (the deviation between the articular line and the noveline) is measured using a tilter.
Fig. one. Portable plate installed on a bite template
Fig. 2. Writing tips are fixed on a hinge axis for graphic
However, this method has disadvantages: 1) It is not always possible to achieve reliable fixation of the bite template; 2) the amortization of the alveolar mucous membrane often gives the distortion of the true position of the bite template; 3) it is necessary to preliminarily definition of the intermediate bite; Fixation to two mutually moving substances (lower jaws and projections of the top of the lower jaw) is not very convenient and does not contribute to the accuracy of the result.
Modification of the facial arc and a method of measuring the angle of the sagittal articular path
L.G. Spiridonov modified the facial arc to determine the angle of the sagittal articular path. His model was tested in practice V.N. Kozhemyakin and I.N. Lose. It is a spring steel strip, a sliding clipped in plastic clips (Fig. 3), which allows you to lengthen or shorten the arc depending on the type of face. Thanks to the spring properties, the arc is tightly pressed against the face and, thus, is not associated with movable substances.
Fig. 3. Modified facial arc
The angle of the sagittal articular path is determined at the survey stage. The arc is focused on the face with its top edge on the noveline (Fig. 4). Then a panoramic radiograph is made. It can be studied by the condition of the teeth, maxillary bones and the temporomandibular joints. To determine the angle of the sagittal articular path on the X-ray diffraction pattern on the articular surface of the articular tubercle temporal bone A line is carried out before intersection with the upper surface of the shadow of the face arc (on the shade can also be carried out). The resulting angle (this is the angle of the sagittal articular path) is measured using a tilter (Fig. 5).
Fig. four. Facial arc installed on the face
Fig. five. Determination of the angle of the sagittal articular path on the radiograph
The modified measurement method described above is easy to use, is available and does not require additional costs for the manufacture of models, a hard base on the lower jaw with a bite template, installation of a portable plate and registration cards. The method gives maximum information about the state of the dental system.
Literature
1. Sapozhnikov A.L. Articulation and prosthetics in dentistry. - Kiev: Health, 1984. - 94 p.
2. Khatova V.A. Diagnosis and treatment of disorders of functional occlusion. - N. Novgorod, 1996. - 272 p.
3. GERBER A. // DT. Zahnarztliche ztschr. -1966. -Bd 21, N1.- S. 28-39.
4. GERBER A. // DT. Zahnarztliche Ztschr.-1971. -Bd 26, N2. -S. 119-141.
5. Gysi A. // Hanbuch Der Zahnhailkunde. -Bruhn, 1926. -bd. 3. -s. 167-267.
6. Lehmann G. // Dental Labor. - 1982. - V. 11, N 1575. - S. 10.
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