chewing activity. Statistical methods for determining chewing efficiency. Anatomical features of the teeth
In view of the foregoing, many authors began to work on establishing constant values for determining the chewing pressure of the teeth. For this purpose, the authors used a comparative method for measuring masticatory pressure. Taking the chewing pressure of the weakest tooth, i.e., the lateral incisor, as a unit of measurement, they compared the chewing pressure of the remaining teeth with it. This resulted in quantities that can be called constants, since they are constant. The authors with their method were guided by the anatomical and topographic features of this tooth - the size of the chewing or cutting surface, the number of roots, the thickness and length of these roots, the number of tubercles, the cross section of the neck, the distance of the location of the teeth from the angle of the lower jaw, the anatomical and physiological characteristics of the periodontium, etc. d.
N. I. Agapov took the chewing efficiency of the entire chewing apparatus as 100% and calculated the chewing pressure of each tooth as a percentage, having obtained the chewing efficiency by adding the chewing coefficients of the remaining teeth (Table 5).
Table 5
Chewing coefficients of teeth according to N. I. Agapov
To get an idea of the disorders of the chewing apparatus, the number of teeth is usually counted. This technique is incorrect, since it is not only a matter of the number of teeth, but also their chewing value, their significance for chewing function. The table of chewing coefficients of teeth makes it possible, taking into account the loss of chewing efficiency, to get an idea not only about the number, but also to some extent about the chewing coefficient of teeth. However, this methodology needs to be improved. This amendment was made by N. I. Agapov. When calculating the masticatory effectiveness of a disturbed dentition, only teeth with antagonists should be taken into account. Teeth that do not have antagonists are almost meaningless as chewing organs. Therefore, the count should not be by the number of teeth, but by the number of pairs of articulating teeth (Table 6).
This amendment is very significant and the use of this amendment gives completely different figures than the definition of chewing efficiency without this amendment. An example is a dental formula:
Not a single tooth
Without correction, chewing efficiency is 50%, meanwhile, when using N.I. Agapov's amendment, chewing efficiency is equal to o, because the patient does not have a single pair of antagonizing teeth.
I. M. Oksman offers the following chewing coefficients for lost teeth of the upper and lower jaws (Table 7).
Table 7
Chewing coefficients of teeth according to I. M. Oksman
M. Oksman considers it necessary, in addition to the functional value of lost teeth, to take into account the functional state of the remaining teeth. The functional state should be assessed by tooth mobility. Teeth with pathological mobility of the first degree are considered normal, teeth of the second degree - as teeth with only 50% chewing value, teeth with pathological mobility of the third degree, as well as multi-rooted teeth with acute periodontitis - are considered as missing. Teeth affected by caries, which can be filled, should be considered full.
According to N.I. Agapov, the absence of a tooth in one jaw is regarded as the absence of two teeth (the indicated tooth and the antagonist of the same name).
Taking this into account, I. M. Oksman suggests keeping a record in the form of a fraction: in the numerator, a number is written indicating the loss of chewing efficiency on upper jaw, and in the denominator - a figure indicating the loss of chewing efficiency in the lower jaw. This designation of functional value gives a correct idea of the prognosis and result of prosthetics. The calculation of chewing efficiency according to I. M. Oksman is undoubtedly more appropriate than according to N. I. Agapov, since according to this scheme, the doctor gets a more complete picture of the state of the dentoalveolar system.
V. Yu. Kurlyandsky proposed a static method for determining the functional state of the supporting apparatus of the teeth, which he called a periodontogram. A periodontogram is obtained by entering information about each tooth and the endurance of its supporting apparatus (Table 8) in a special
Table 8
Changes in periodontal endurance with varying degrees of atrophy
according to V. Yu. Kurlyandsky
Teeth numbering |
Designations. |
Of five lines. |
The purpose of the periodontogram is to enable the clinician to compare the functional value of different groups of teeth in the upper jaw with the corresponding groups of teeth in the lower jaw. But this goal, unfortunately, is not achieved by the author of the periodontogram. Firstly, the author himself writes: “All the frontal teeth of the upper and lower jaws may not participate in the act of biting off food, as a result of which all the above calculations will not reflect the true power relationships between the antagonistic groups of teeth when biting off food.” Secondly, "in one case, the front teeth are used for chewing food (in the absence of chewing teeth or their pain), and in the other, chewing teeth, mainly premolars, are used to bite off food." Therefore, already, according to the author himself, the parodontogram is unsatisfactory.
In addition, to determine the performance of each tooth, the author uses the Haber table, compiled on the basis of gnatodi - namometry data. Meanwhile, gnathodynamometry is a vicious method for the following reasons:
1. Gnatodynamometry gives an idea only of masticatory pressure in the vertical direction and does not take into account pressure in other directions, and also does not take into account the actions of other components that affect masticatory efficiency, namely the quantity and quality of saliva, the neuroglandular apparatus of the oral cavity, masticatory and mimic muscles, anatomical and physiological features of the tongue, etc.
2. When using gnathodynamometry, the chewing pressure of each tooth is measured separately, meanwhile the dentition is not the sum of teeth, but a dental system in which there is a close interdependence both between individual elements, it, and between each element and the entire the system as a whole.
3. Gnathodinamometry does not take into account individual characteristics of the dental system in various patients, but is a standard method, which is contrary to the principles of Soviet medicine.
4. As regards, in particular, the data according to Haber, this is the worst gnatho - dynamometric method, because the data obtained by him are mythical (1408 kg) and in no way correspond even to the average figures of the chewing efficiency of the teeth.
Thus, gnathodynamometry is not able to give a correct idea of the state of intact teeth.
5. The situation is even worse when determining the state of the supporting apparatus of teeth affected by periodontal disease using the method of V. Yu. Kurlyandsky. He suggests measuring pocket depth, but pocket depth is determined by measuring the deepest point of the pocket. Meanwhile, it is known that the depth of the pathological pocket is uneven and the general condition of the entire pocket cannot be determined in this way. In addition, it is known that the expansion of the periodontal gap is no less important for establishing the nature of atrophy, and the last measurement of the depth of the pocket does not give any idea.
Chewing activity is an important indicator of the state of the dental structure. This is the power of the chewing muscles of the lower jaw, which is necessary for biting, crushing and crushing food. It is measured on separate segments of the dentoalveolar system.
Gnatodynamometry is a method of measuring the pressure of the muscles of the masticatory apparatus, as well as the resistance of dental tissues to the force of compression of the jaws.
This technique is implemented by means of a device called a gnatodynamometer.
Most of the authors working with this topic took the chewing force of the weakest tooth as a unit. And the pressure of other teeth was determined in comparison with it. When calculating the masticatory pressure constant, the author was guided by the following anatomical features of the tooth:
- surface dimensions;
- number of roots;
- the presence of bumps;
- interval from the angle of the lower jaw;
- transverse section of the neck;
- characteristics of the periodontium.
Research procedure
Measurement of masticatory tension can be carried out using an electronic gnatodynamometer Rubinov and Perzashkevich. into it includes special sensors built into the measuring head of the removable nozzle. A brass plate is located in the sensor connected to the microammeter.
The patient is comfortably seated in the chair. There must be no psychological stress. A nozzle is inserted into the mouth between the jaws and compressed by the teeth until pain. At this moment, the pressure is displayed on the scale of the device. The indicators are fixed.
On the practical significance of indicators
Gnathodinamometric indicators depend on many factors:
- gender of the person;
- individual characteristics;
- diseases (, and others);
- partial loss of teeth;
- age.
Indicators on the device are reflected in kilograms. The average data ranges from 15-35 for the anterior and 45-75 kg for the molars. They are essential for optimizing the process of prosthetics, as they reveal the sensitivity of the periodontium to functional load, helping to determine the design of the necessary prosthesis.
The average indicators of masticatory pressure are determined, taken as the basis for measurements and the correspondence of the periodontal endurance load:
- on the incisors in women - 20-30 kg;
- on molars in women - 40-60 kg;
- on the incisors in men - 25-40 kg;
- on molars in men - 50-80 kg.
Chewing pressure on each tooth in kilograms
There are tables of different authors with the distribution of chewing force for each tooth, they are also approximate. Endurance of periodontal tissue as a whole (1408 kg in men and 936 kg in women) is almost never realized, because the maximum power of contraction of the masticatory apparatus is 390 kg.
Gnatometry is rarely used in modern dentistry due to the following disadvantages:
- only vertical pressure is measured in the absence of horizontal force;
- the results cannot be called absolutely accurate;
- there is a rapid deformation of the spring;
- in addition, the results are determined by the psychosomatic state, which even in the same person changes during the day.
It is interesting to know what will happen if lost chewing teeth are not replaced with dentures:
History pages
Chewing force began to be measured as early as the 7th century. The most famous anatomist and physiologist of the time, Giovanni Borelli, is considered the first to make such attempts. His method is quite simple. A weight was attached to a rope tied behind the lower tooth, causing muscular resistance. The weight limits of the weights were equal to 200 kg. The disadvantage of this method is that the work of the muscles of the neck muscles, which also took part in the resistance, was not taken into account.
Black became the next innovator in this area at the end of the 19th century. He is considered the first author of the gnatodynamometer. The first device consisted of two plates with a spring between them and resembled a mouth expander. The device was improved in 1919 by Gaber, and in 1941 by Thyssenbaum M.S. In these devices, only the vertical chewing load was determined.
In 1948 Kleitman I.A. designed a dynamometer that also experiences horizontal pressure. Device designs have been improved to this day. Instruments are electronic, photometric, mechanical.
Methodology Agapova N.I. is based on calculating the strength of each of the teeth as a percentage of the entire chewing apparatus.
As a rule, to assess violations of the chewing apparatus, a general count of the number of teeth is used. Agapov considers this to be fundamentally wrong. After all, their strength and effectiveness are different. He developed a table that distributes the coefficients between the teeth.
An important correction is his conclusion that teeth are only effective in pairs. Teeth that have lost antagonists practically lose their main function. Therefore, if one tooth is missing, two are missing. And the calculation of chewing activity, respectively, should be carried out according to the number of paired teeth. When using this correction, the values are completely different.
Oksman's amendments
In turn, Oksman I.M. indicates the importance and necessity of taking into account the activity of the remaining teeth in accordance with their mobility. With the first degree of pathological tooth mobility, chewing activity corresponds to 100%. At the second degree - 50%, and at the third - the absence of chewing activity is stated. The affected teeth also belong to the third degree.
Oksman, taking into account the developments of Agapov, introduced the entry of antagonist teeth in the form of a fraction. The numbers indicating the loss of chewing activity are recorded in the following order: in the numerator - the maxillary indicator, in the denominator - the mandibular indicator. According to this scheme, it is more convenient for the doctor to imagine the state of the dentoalveolar apparatus.
Gnatodynamometric data are important in and at. Their value is influenced by: psychological experiences, compensatory abilities of periodontal receptors, measurement reactivity and numerous other factors.
Through gnathometry, the following is carried out: measuring the pressure force between pairs of teeth, evaluating the functionality of prostheses, tracking the dynamics of therapeutic measures and the functionality of implants.
Before exploring the issue of methods for measuring chewing effectiveness, you need to understand four concepts that are often confused: chewing power, chewing efficiency, chewing pressure and chewing power. Chewing force is called in physiology the force that can be developed by the entire chewing muscles that lift the lower jaw. It is, according to Weber, an average of 390-400 kg [the physiological diameter of all three pairs of muscles of the lower jaw lifters is 39 cm 2 (m. temporalis \u003d 8 cm 2, m. masseter \u003d 7.5 cm 2, m. pterygoideus medialis \u003d 4 cm2, and 1 cm2 of the area of \u200b\u200bthe physiological diameter of the muscle can develop a force of 10 kg; therefore, all lifters can develop a force of 390-400 kg).
Dentists, however, are not interested in the absolute, not potential strength that can be developed by the chewing muscles, but in the strength that the chewing muscles develop during the chewing function. The chewing value of the dentition cannot be measured in kilograms. It can be determined in comparative terms by the degree of food grinding. The degree of grinding, to which the food is brought by the dentoalveolar system, while it performs the function of chewing, is called chewing efficiency. S. E. Gelman uses instead of the term "chewing efficiency" the term "chewing power". But power in mechanics is the work done per unit of time, it is measured in kilogram meters. The work of the chewing apparatus can be measured not in absolute units, but in relative units - by the degree of food grinding in the oral cavity as a percentage. Therefore, the result of the work of the masticatory apparatus per unit time in percent cannot be called masticatory power; it would be more correct to call it chewing efficiency. Chewing efficiency measured as a percentage compared to an intact dentition, the chewing efficiency of which is taken as 100%.
In dentistry (at the suggestion of Prof. S. E. Gelman), the term “chewing pressure” is used. Chewing pressure S. E. Gelman calls that part of the chewing force that can be realized only in one part of the dentoalveolar system. Chewing pressure is measured in kilograms using a gnatodynamometer.
Gnatodynamometry
The measurement of masticatory force has been practiced since the 17th century. In 1679, Borelli wrote about the following method for measuring chewing force. He put a rope on the lower molar, tying its ends, and hung weights from it, thus overcoming the resistance of the masticatory muscles. The weight of the weights, pulling the lower jaw down, was 180-200 kg. This method of measuring chewing force is very imperfect, since it did not take into account that not only chewing, but also cervical muscles took part in holding the load. Black, M. S. Tissenbaum proposed a gnatodynamometer for measuring masticatory pressure (Fig. 47). This device usually resembles a mouth expander: it is equipped with two cheeks that move apart with a spring. The spring pushes the arrow along the scale with divisions, depending on the force of closing the dentition; the arrow shows more or less chewing pressure. Recently, an electronic gnatodynamometer has been developed (Fig. 48).
Gnathodynamometry has the disadvantage that it measures only vertical pressure, and not horizontal pressure, with which a person crushes and grinds food. In addition, the device does not give accurate measurement results, as the spring deteriorates quickly. Some supporters of gnathodynamometry have established, through numerous measurements, the average chewing pressure figures for the teeth of the upper and lower jaws (Table 4).
However, these numbers, just like others obtained by gnathometry, cannot be used as typical indicators, since the value of chewing pressure, expressed in kilograms, depends on the psychosomatic state of the patient during the test, and this state is different for different individuals and even for the same individuals different time. In addition, gnathodynamometry has other disadvantages. Consequently, the given values are not constant, but variable, which explains the sharp discrepancy between the results of measuring chewing pressure according to different authors.
Static methods for determining chewing efficiency according to N.I. Agapov and I.M. Oksman
In view of the foregoing, many authors began to work on establishing constant values for determining the chewing pressure of the teeth. For this purpose, the authors used a comparative method for measuring masticatory pressure. Taking the chewing pressure of the weakest tooth, i.e., the lateral incisor, as a unit of measurement, they compared the chewing pressure of the remaining teeth with it. This resulted in quantities that can be called constants, since they are constant. The authors with their method were guided by the anatomical and topographic features of this tooth - the size of the chewing or cutting surface, the number of roots, the thickness and length of these roots, the number of tubercles, the cross section of the neck, the distance of the location of the teeth from the angle of the lower jaw, the anatomical and physiological characteristics of the periodontium, etc. d.
N. I. Agapov took the chewing efficiency of the entire chewing apparatus as 100% and calculated the chewing pressure of each tooth as a percentage, having obtained the chewing efficiency by adding the chewing coefficients of the remaining teeth (Table 5).
To get an idea of the disorders of the chewing apparatus, the number of teeth is usually counted. This technique is incorrect, since it is not only a matter of the number of teeth, but also their chewing value, their significance for chewing function. The table of chewing coefficients of teeth makes it possible, taking into account the loss of chewing efficiency, to get an idea not only about the number, but also to some extent about the chewing coefficient of teeth. However, this methodology needs to be improved. This amendment was made by N. I. Agapov. When calculating the masticatory effectiveness of a disturbed dentition, only teeth with antagonists should be taken into account. Teeth that do not have antagonists are almost meaningless as chewing organs. Therefore, the count should not be by the number of teeth, but by the number of pairs of articulating teeth (Table 6).
This amendment is very significant and the use of this amendment gives completely different figures than the definition of chewing efficiency without this amendment. An example is a dental formula:
Without correction, chewing efficiency is 50%, meanwhile, when using N.I. Agapov's amendment, chewing efficiency is 0, because the patient does not have a single pair of antagonizing teeth. I. M. Oksman offers the following chewing coefficients for lost teeth of the upper and lower jaws (Table 7).
IM Oksman considers it necessary, in addition to the functional value of lost teeth, to take into account the functional state of the remaining teeth. The functional state should be assessed by tooth mobility. Teeth with pathological mobility of the first degree are considered normal, teeth of the second degree - as teeth with only 50% chewing value, teeth with pathological mobility of the third degree, as well as multi-rooted teeth with acute periodontitis - are considered as missing. Teeth affected by caries, which can be filled, should be considered full.
According to N.I. Agapov, the absence of a tooth in one jaw is regarded as the absence of two teeth (the indicated tooth and the antagonist of the same name). Considering this, I. M. Oksman suggests keeping a record in the form of a fraction: in the numerator, a number is written indicating the loss of chewing efficiency in the upper jaw, and in the denominator - a figure indicating the loss of chewing efficiency in the lower jaw. This designation of functional value gives a correct idea of the prognosis and result of prosthetics. The calculation of chewing efficiency according to I. M. Oksman is undoubtedly more appropriate than according to N. I. Agapov, since according to this scheme, the doctor gets a more complete picture of the state of the dentoalveolar system.
Periodontogram AO V.Yu. Courland
V. Yu. Kurlyandsky proposed a static method for determining the functional state of the supporting apparatus of the teeth, which he called a periodontogram. A periodontogram is obtained by entering information about each tooth and the endurance of its supporting apparatus (Table 8) into a special drawing with symbols.
The drawing consists of five lines. The third line contains the designations of each tooth (dental formula) in Arabic numerals. Two rows of cells above the dental formula are designed to record the state of the supporting apparatus of each tooth of the upper jaw, and two rows of cells under the dental formula are used to record the state of the supporting apparatus of the teeth of the lower jaw (Table 9).
The purpose of the periodontogram is to enable the clinician to compare the functional value of different groups of teeth in the upper jaw with the corresponding groups of teeth in the lower jaw. But this goal, unfortunately, is not achieved by the author of the periodontogram. Firstly, the author himself writes: “All the frontal teeth of the upper and lower jaws may not participate in the act of biting off food, as a result of which all the above calculations will not reflect the true power relationships between the antagonistic groups of teeth when biting off food.” Secondly, "in one case, the front teeth are used for chewing food (in the absence of chewing teeth or their pain), and in the other, chewing teeth, mainly premolars, are used to bite off food." Therefore, already, according to the author himself, the parodontogram is unsatisfactory.
In addition, to determine the performance of each tooth, the author uses the Haber table, compiled on the basis of gnathodynamometry data. Meanwhile, gnathodynamometry is a vicious method for the following reasons:
1. Gnatodynamometry gives an idea only of masticatory pressure in the vertical direction and does not take into account pressure in other directions, and also does not take into account the actions of other components that affect masticatory efficiency, namely the quantity and quality of saliva, the neuroglandular apparatus of the oral cavity, masticatory and mimic muscles, anatomical and physiological features of the tongue, etc.
2. When using gnathodynamometry, the chewing pressure of each tooth is measured separately, meanwhile, the dentition is not the sum of teeth, but a dental system in which there is a close interdependence both between its individual elements, and between each element and the entire system as a whole.
3. Gnathodinamometry does not take into account the individual characteristics of the dental system in various patients, but is a standard method, which contradicts the principles of Soviet medicine.
4. As for, in particular, the data according to Haber, this is the worst gnatodynamometric method, because the data obtained by him are mythical (1408 kg) and in no way correspond even to the average figures for the chewing efficiency of the teeth. Thus, gnathodynamometry is not able to give a correct idea of the state of intact teeth.
5. The situation is even worse when determining, according to the method of V. Yu. Kurlyandsky, the state of the supporting apparatus of teeth affected by periodontal disease. He suggests measuring pocket depth, but pocket depth is determined by measuring the deepest point of the pocket. Meanwhile, it is known that the depth of the pathological pocket is uneven and the general condition of the entire pocket cannot be determined in this way. In addition, it is known that the expansion of the periodontal gap is no less important for establishing the nature of atrophy, and the last measurement of the depth of the pocket does not give any idea.
6. In addition, it should be added that bone tissue atrophy and the depth of the gingival pocket characterize the morphological features of the pathological process. Meanwhile, at the modern level of medical science, it is necessary to take into account not only morphological disorders, but also the functional state of tissues in the issue of diagnosis.
Thus, the unsatisfactory method of using chewing coefficients according to Haber is aggravated by the use of an inferior method for measuring the pocket depth, and the data obtained using a periodontal chart do not correspond to reality.
Dynamic Method for Determination of Chewing Efficiency
For a correct judgment about the functional ability of the masticatory apparatus, a dynamic method is necessary, i.e., it is necessary to take into account all movements of the lower jaw and the state of all elements of the masticatory apparatus "participating in the act of chewing: neuroreflex connections, glandular and motor apparatus of the oral cavity, soft tissues of the oral cavity etc. In addition, in the correct assessment of the state of the chewing apparatus, the features of the dentoalveolar system play a role: the ratio of the dentition, the ratio of the jaws, the intensity of chewing, depending on the number of chewing movements and the force of chewing pressure.The number of articulating teeth is especially important in the dynamics of the lower jaw.
The act of grinding food consists, as you know, of three moments: cutting, crushing and grinding food. All this work is accompanied by profuse salivation. The usefulness of mechanical processing depends on the number of articulating teeth during the movement of the dentition. At in large numbers articulating teeth food grinding is improved. Meanwhile, the degree of food grinding, depending on the number of articulating teeth and other specified factors that are important for the functional state of the dentition, can only be detected during chewing. Therefore, the most valuable method for measuring chewing efficiency in an intact dentoalveolar system is the method of functional diagnostics of the masticatory apparatus. This method can be carried out using a functional chewing test, mastication, mastication dynamometry, myography and myotonometry. We will describe only the first two methods for determining chewing efficiency.
Functional chewing test according to S.E. Gelman
S. E. Gelman, who studied and modified the Christiansen chewing functional test method, found that persons with a full-fledged chewing apparatus, who have one hundred percent chewing efficiency, chew 5 g of almonds well for 50 seconds, grinding them during this time until they are chewed after drying, the mass passes freely through a sieve with holes, the diameter of which is 2.4 mm. If there are defects in the dentition, the almonds are not completely crushed within 50 seconds, and therefore only part of the chewed mass passes through the sieve. In this regard, S. E. Gelman proposes the following method of functional chewing test. The patient is offered to chew 5 g of almonds for 50 seconds, then the patient spits out the whole mass (it is dried and sifted through a sieve with holes of 2.4 mm). If the mass of chewed almonds is screened, this means that the chewing efficiency is 100%; if only a portion is sifted, the percentage loss in chewing efficiency can be calculated by taking 1 g of unsifted almonds as 20% loss in chewing efficiency (see "Determination of functional chewing test"). To study the effectiveness of oral cavity sanitation or prosthetics, as well as the effectiveness of any prosthesis design, the method of functional diagnostics in the form of a chewing test is almost indispensable and should be widely introduced into practice.
Giving a chewing test. Weigh 5 g of almonds or apricot seeds. It is advisable to prepare bags with weighed portions in advance. The subject sits down at a table on which there is a small porcelain cup and a glass of boiled water at room temperature (14-16°C). He is offered to take all 5 g of grains into his mouth and start chewing on a signal. After the word “begin,” the subject begins to chew the grains. The beginning of chewing is marked on the stopwatch. After 50 seconds, a signal is given, according to which the subject stops chewing and spits out the entire mass into the cup, then he rinses his mouth and spits out water into the same cup. If the patient has removable dentures, they are removed from the mouth and rinsed over the same cup. 5-10 drops of 5% sublimate solution are poured into the cup for disinfection. It is very important that there is a calm atmosphere in the laboratory during the study. The subject should sit quietly, not rush, not be nervous. To do this, it is necessary to briefly inform him about the purpose of the test and its duration.
Sample processing. The chewed mass is filtered through gauze. To do this, a medium-sized glass or metal funnel (8-10 cm in diameter) is inserted into a glass hollow cylinder or into an ordinary bottle. A gauze square measuring 15 X 15 cm is moistened with water and placed on the funnel so that the gauze sags, and its free edges descend over the edge of the funnel. With the left hand, gauze is pressed against the edge of the funnel, and the contents of the cup are poured onto the gauze with the right hand. If sediment remains at the bottom of the cup, pour a little water into it, shake it up and quickly pour it onto cheesecloth. The edge of the gauze during filtering should not go down into the funnel, since in this case part of the mass can slip into the lower vessel. If this happens, then you should straighten the edges of the gauze, fix it to the edge of the funnel, rearrange the funnel into another spare vessel and pour the contents of the first vessel into it. Given the possibility of such cases, each chewing sample must be strained over a completely empty clean vessel.
After filtering, the gauze with the remaining mass is placed in a medium-sized porcelain cup or on a tea saucer. To dry the mass, a cup with gauze is transferred to a water bath of the appropriate size, and in the absence of one, in a saucepan or a deep metal cup filled with water, the cup is put on fire. Drying in the closet; more painstaking; in addition, there is no guarantee against overdrying and charring of the mass, which can lead to a change in the shape and weight of the particles. When the whole mass dries, the cup with gauze is removed from the water bath, put on the table and the gauze with the mass on its surface is separated from the bottom of the cup, after which light movements hands freely remove the entire mass from the gauze into a cup. The latter is again placed for some time in the bath to finally bring the sample to a dry state. Before the end of drying, the mass must be mixed several times with a porcelain or metal spatula. With the same spatula, clean the mass from the bottom of the cup. The mass is considered completely dried if, when kneaded between the fingers, it does not stick together into a lump, but easily crumbles. During drying, it is necessary to ensure that water does not boil away in a water bath, as this can lead to overdrying or even charring of the mass.
For sieving the dried mass, a metal sieve with round holes with a diameter of 2.4 mm is used. Such holes of the same diameter in all directions are more accurate meters than the square holes of Christiansen sieves. The sieve can be made from any aluminum or tin cup of small size, in the bottom of which holes are drilled with a round bur with a diameter of 2.4 mm. The sieve is placed over some dry cup, the whole mass is poured into the sieve, lightly and, shaking, sift out all the finely chewed mass. Only particles with a diameter greater than the diameter of the holes remain on the sieve. Sifting must be done carefully, stirring the mass often, preferably with a wooden stick, so that all sufficiently crushed pieces pass through the holes. Part of the mass remaining on the sieve is carefully poured onto a watch glass and weighed to the nearest hundredth of a gram. To facilitate and speed up the work, it is necessary to have several pre-weighed watch glasses in stock. The resulting weight is converted into a percentage of the entire standard weight (5 g) using a simple formula.
Physiological test according to I.S. Rubinov
I. S. Rubinov developed the following physiological tests for taking into account the effectiveness of the act of chewing. The subject is asked to chew one nut kernel weighing 800 mg (the average weight of the nut) on a certain side until the swallowing reflex appears. The patient spits out the chewed mass into a cup, rinses his mouth with water and spits it out into the same cup. Subsequently, the mass is processed according to Gelman, i.e., washed, dried and sieved through a sieve with round holes of 2.4 mm, the resulting residue is weighed. For the same purpose, he used cracker (500 mg) and a piece of soft bread weighing 1 g, equal to the volume of the nut kernel, and the chewing time before swallowing these pieces was taken into account. These studies have shown that as the state of the masticatory apparatus deteriorates, the chewing time to swallow lengthens and the size of swallowed particles increases. For example, in adults with a complete chewing apparatus, the duration of chewing one nut kernel before swallowing is on average 14 seconds, and the residue in the sieve is 0. In the absence of 2-3 teeth on one side, the chewing time before swallowing one nut kernel is 22 seconds, and the remainder in a sieve is 150 mg. With unsatisfactory complete dentures, the chewing time of one nut kernel before swallowing is 50 seconds, and the residue in the sieve is 350 mg. The difference in indicators is most clearly revealed when chewing a nut, weaker - when chewing a cracker and even weaker - when chewing soft bread.
I. S. Rubinov indicates that the test with chewing one nut kernel before swallowing, compared with 5 g, consisting of several kernels, is closer to normal natural food irritation and allows you to take into account the effectiveness of chewing in different parts of the dentition and individual groups of articulating teeth. The single core test can also be successfully used to evaluate chewing effect in percent. The percentage is calculated as in the sample according to S. E. Gelman, i.e. the weight of the nut kernel refers to the residue in the sieve, as 100: x.
If the patient is not able to chew the kernel of the nut, then a test with a cracker can be applied. The criterion for judging the effectiveness of chewing is the duration of chewing before swallowing (the period of chewing a rusk before swallowing is on average 8 seconds). When chewing a cracker, a complex set of motor and secretory reflexes is obtained. These reflexes are active from the moment a piece of food enters the mouth. In this case, the motor reflex is associated with crushing the cracker, and the secretory reflex is associated with the release of saliva, which wets and lubricates the rough particles of the cracker before swallowing.
Facilitating pulverization nutrients, chewing movements increase the impact of saliva and contribute to the rapid formation of a lump and its swallowing. I. S. Rubinov's observations showed that with the appearance of dry mouth after taking atropine, the chewing time before swallowing lengthens, and the size of the swallowed pieces increases.
Mastication according to I.S. Rubinov
I. S. Rubinov, studying the mechanism of reflexes carried out in the oral cavity, developed a graphical method for accounting for the motor function of the masticatory apparatus. With the help of special devices (masticograph), all kinds of movements of the lower jaw are recorded on a kymograph or oscilloscope tape. According to the curves, one can judge the nature of the chewing movements of the lower jaw. This method is called by the author mastication (chewing recording).
The essence of this method lies in the fact that with the help of a masticatsiograph, consisting of a rubber balloon and a plastic case, all possible movements of the lower jaw are recorded on a rotating tape of the kymograph by air transmission through the Marey capsule (Fig. 49).
Graphically, the normal acceptance of one piece of food until the moment of swallowing is characterized by five phases (Fig. 50). On the masticogram, each phase has its own characteristic graphic pattern.
I phase- resting phase - before the introduction of food into the mouth. At the same time, the lower jaw is motionless, the muscles are in minimal tone, the lower dentition is 2-3 mm apart from the upper one. On the masticogram, this phase is indicated as a straight line (I) at the beginning of the chewing period at a level between the base and top of the wavy curve.
II phase- the phase of introducing food into the mouth. This phase corresponds to the moment the piece of food is introduced into the mouth. Graphically, this phase corresponds to the first ascending leg of the curve (II), which begins immediately from the line of rest. The swing of this knee is maximally pronounced, and its steepness indicates the speed of introduction of food into the mouth.
III phase- the phase of the beginning of the chewing function, or the indicative phase. This phase begins from the top of the ascending knee and corresponds to the process of adaptation to chewing a piece of food and its further mechanical processing. Depending on the physical and mechanical properties of food, changes occur in the rhythm and scope of the curve of a given phase. At the first crushing of a whole piece of food in one movement (method), the curve of this phase has a pronounced flat top (plateau), turning into a gentle downward knee to the level of the line of rest. During the initial crushing and compression of a separate piece of food in several stages (movements) by searching for best place and positions for compression and crushing, there are corresponding changes in the nature of the curve. Against the background of a flat plateau (top) there are a number of short additional undulating rises located above the level of the line of rest.
IV phase- phase of the main chewing function. Graphically, this phase is characterized by the correct alternation of periodic masticatory waves. The nature and duration of these waves in a normal chewing apparatus depend on the consistency and size of a piece of food. When chewing soft food, frequent uniform rises and descents of chewing waves are noted. When chewing solid food at the beginning of the phase of the main chewing function, there are more rare descents of the chewing wave. The harder the food and the greater the resistance, slowing down the moment of raising the lower jaw, the more gentle the downward knee. Then, sequentially, the ups and downs of the masticatory waves become more frequent. The intervals between individual waves (0) correspond to pauses when the lower jaw stops during closing. The value of these intervals indicates the duration of stay of the dentition in the stage of closing. Closing can be with the contact of the chewing surfaces and without contact. This can be judged by the level of location of the line of intervals or "closing loops", as they will be referred to below. The location of the "loops of closure" above the level of the line of rest indicates the absence of contact between the dentition. If the "loops of closure" are located below the line of rest, then this means that the chewing surfaces of the teeth are in contact or close to contact.
The width of the loop formed by the descending knee of one chewing wave and the descending knee of the other indicates the speed of the transition from closing to opening of the dentition. The sharp angle of the loop indicates that the food has undergone a short-term compression. An increase in this angle indicates a longer duration of food compression between the teeth. The straight platform of this loop indicates a corresponding stop of the lower jaw in the process of crushing food. A “closing loop” with a wave-like rise in the middle (0) indicates rubbing of food during sliding movements of the lower jaw. The graphical picture of the curve of the main phase of the chewing function described above gives an idea of how the sequential compression and crushing of food and its rubbing takes place.
V phase- the phase of lump formation followed by swallowing it. Graphically, this phase is marked by a wavy curve with some decrease in the height of these waves. The act of forming a lump and preparing it for swallowing depends on the properties of the food. With soft food, a lump is formed in one step; with solid crumbly food, it is formed and swallowed in several steps. Corresponding to these movements, curves are recorded on a rotating kymograph tape. After swallowing the food bolus, a new state of rest of the chewing apparatus is established. Graphically, this state of rest is represented as a horizontal line (1). It serves as the first phase of the next chewing period.
The ratio of the duration of the individual phases of the masticatory period and the nature of the sections of the curve vary depending on the size of the food bolus, food consistency, appetite, age, individual characteristics, the state of the neuroreflex connections of the masticatory apparatus and the central nervous system. When using the mastication method, the appropriate recording apparatus should be used correctly, and the analysis of the curves should be based on accurate knowledge of the physiological foundations of the masticatory apparatus.
Diagnosis- is a logical conclusion, a synthesis of the obtained subjective and objective research data. Diagnosis in orthopedic dentistry should reflect the size and topography of defects in hard tissues of teeth, dentition, condition oral mucosa, as well as concomitant diseases of the dentoalveolar system and complications.
For example: 1) dental hard tissue defect(mandatory what?), carious, non-carious or traumatic origin (non-carious diseases include: hypoplasia enamel, wedge-shaped defects, fluorosis, acid necrosis and pathological abrasion; trauma - acute and chronic), the degree of destruction of the crown part of the tooth must be indicated. 2) partial adentia(which jaw?) according to Kennedy: bilateral terminal (I class), unilateral terminal (P class), included in the region of the lateral teeth (III class), isolated included in the frontal region (1U class). Complications: traumatic occlusion, decreasing bite, secondary deformation(the phenomenon of Godon-Popov). .3) complete edentulous: the degree of atrophy according to I.M. Oksman, the compliance of the mucous membrane according to Supple.
Plan for preparing the oral cavity for prosthetics: sanitation of the oral cavity (removal of dental deposits, dental treatment, extraction of teeth or roots); special training ( depulping teeth, elimination of occlusal disorders, orthodontic preparation, alveolotomy, excision of scars, strands of the mucous membrane, deepening of the vestibule or floor of the mouth).
tab, veneer from what material and on what tooth;
pin construction (single-root, collapsible, how it was made, temporary, permanent) on the supporting tooth;
Single crown (from what material) on the supporting tooth;
Bridge prosthesis from what material, with supports on which teeth;
Partially removable laminar denture for high, low, with which teeth (plastic, ceramic, porcelain), clasps for which teeth;
Clasp prosthesis(splinting clasp prosthesis) indicating the fixation system ( cast clasps, type of attachments, telescopic crowns) and on which teeth;
Other types of designs are possible with an indication of the type of materials, manufacturing method and supporting teeth.
Diary- displays the date of admission of patients, the amount of work performed and must be certified by the signature of the immediate supervisor.
Dispensary observation: if necessary, the date of the examination (year, month) of the subsequent visit is noted for the following diseases: pathological abrasion, periodontal tissue diseases, complete adentia, etc.
Epicrisis: the volume of orthopedic treatment is described (aesthetics, anatomical shape of the teeth, the integrity of the dentition, the height of the lower third of the face, the mobility of the teeth), it is indicated to what extent the chewing efficiency is restored (according to I.M, Oksman). recommendations are given for oral care and the use of prostheses.
Role-playing game"Maintaining an outpatient card of a dental patient"
FULL NAME. Ivanov V.P.
Year of birth. 1991.
Current complaints: violation chewing, aesthetics.
Disease history: A day ago, the crown of the central tooth of the upper jaw broke off when eating. The tooth was treated three years ago due to complications of caries.
General state: bad habits- smokes; concomitant diseases - no; hepatitis, tuberculosis, syphilis, HIV- denies; allergic anamnesis- unburdened anesthesia previously performed, effective, without pathologies.
Visual inspection: skin color - clear; the face is symmetrical; face type - conical; the height of the lower third of the face is not a change; the chin does not protrude; lips close - without tension; nasolabial and chin folds - moderately pronounced; mouth opening - free, painless; movements of the lower jaw - smooth, displacement during movement - no.
Study TMJ: the presence of a crunch, clicking, noise in the TMJ during the movement of the lower jaw is not recorded, the masticatory muscles are painless on palpation, the submandibular lymph nodes are palpation painless, not enlarged.
objective data
P | R | P | P | ||||||||||||
P | P | P | |||||||||||||
Inspection SOPR: the mucosa is pale pink, of moderate humidity, the gingival papillae are normal.
Examinations of teeth and dentition:
Intact teeth are without pathology, not mobile, percussion, probing are painless, the temperature reaction is negative, periodontal pockets are 0.1 mm.
- fillings are in a satisfactory condition, they correspond to the bite, the marginal diligence is dense.
Teeth are not mobile percussion sounding- painless, temperature reaction is negative. IROPZ 16; 25; 26; 36; 44; 45 - 0.5.
View bite: fixed, straight.
Condition of the dentition: the shape of the dentition is elliptical in the upper jaw, parabolic in the lower jaw. There are no secondary deformations.
Language: normal size, oval, frenulum - normal.
Additional examination methods:
From 07/05/2010. on the intraoral radiograph, in the periapical tissues of the 21st tooth without pathological changes, the canal was sealed up to the physiological apex, throughout.
Or according to I.M. Oksman
teeth | Total | ||||||||
V/H | 25% | ||||||||
LF | 25% |
Loss of chewing efficiency - 3% according to I.M. Oksman.
Diagnosis– defect hard tissues of the tooth as a result of caries, destruction of the crown 21 on 1/2 of the surface, IROPZ 16; 25; 26; 36; 44; 45 - 0.5; loss of chewing efficiency 3% according to I.M. Oksman.
Oral preparation plan prosthetics did not carry out.
Orthopedic treatment plan: stump pin design for 21 teeth; single metal-ceramic crown for 21 teeth.
DIARY
date | Amount of work performed | Manager's signature |
5.07.2010 | survey, documentation. Preparing the root of the 21st tooth for a stump pin structure, modeling the pin structure in the oral cavity with Lavax wax, applying a temporary filling - dentin paste. | |
6.07.2010 | checking and fitting of a metal stump pin structure on the root of the 21st tooth. Honey. treatment of the root and canal of the 21st tooth with 3% hydrogen peroxide and liquid for degreasing the canals, air; metal stump pin structure - 95% alcohol, air. Fixation of a metal stump pin structure in the root of the 21st tooth on Fuji. | |
7.07.2010 | under application anesthesia with the Ludoxor spray, the introduction of a retraction thread into the periodontal sulcus of the 21st tooth, the preparation of the 21st tooth for a metal-ceramic crown. Removal of a double impression from the upper jaw "Spidex", from the lower jaw - an alginate impression "Hydrogum soft | |
8.07.2010 | determination and fixation of central occlusion. | |
10.07.2010 | checking and fitting of a cast frame of a metal-ceramic crown for 21 teeth. Determining the color of ceramic cladding: Ivoclar - 4 A. | |
12.07.2010 | checking and fitting of a metal-ceramic crown for 21 teeth. Honey. treatment of the stump of the 21st tooth with 3% hydrogen peroxide, air; metal-ceramic crown - 95% alcohol, air. Fixation of a ceramic-metal crown for 21 teeth on Fuji. Advice and recommendations for the care of the oral cavity and prostheses are given. |
Dispensary observation: the patient does not need, recommended prophylactic oral examination once every six months.
Epicrisis: as a result orthopedic treatment defect hard tissues of the 21st tooth, the anatomical shape, aesthetics, integrity of the dentition of the upper jaw, chewing efficiency in full (100%) were restored.
Patient V.P. Ivanov, born in 1991, was given the necessary recommendations for caring for the oral cavity and a metal-ceramic crown on the 21st tooth.
Homework to clarify the topic.
Questions for self-preparation:
What is meant by medical documentation?
What is meant by medical history?
Procedure for maintaining an outpatient card?
Features of collecting complaints, anamnesis, studying the general somatic condition?
Features of the external examination?
Features of the examination of the oral cavity itself?
Features of additional examination methods?
Diagnosis, features of its setting?
Test tasks:
Initial test knowledge control
Option 1
1. A SYSTEM OF ACCOUNTING AND REPORTING DOCUMENTS INTENDED FOR RECORDING AND ANALYZING DATA CHARACTERIZING THE HEALTH STATE OF INDIVIDUALS AND POPULATION GROUPS, THE VOLUME, CONTENT AND QUALITY OF MEDICAL CARE PROVIDED, AS WELL AS THE ACTIVITY OF THE MEDICAL AND PREVENTIVE INSTITUTIONS ARE CALLED:
1) orthopedic dentistry;
2) prevention;
3) medical statistics;
Medical documentation.
2. IN THE CLINIC OF ORTHOPEDIC DENTISTRY PATIENTS MAKE COMPLAINTS ABOUT:
1) the presence of a cavity in the tooth;
2) pain in the tooth under the crown;
3) pain in the tooth when taking sweets;
Night pain in the tooth.
3. WHEN Clarifying the GENERAL CONDITION OF THE ORGANISM, THE FOLLOWING IS NOTICED:
1) patient complaints;
2) with what the patient associates the development of the disease;
3) allergic anamnesis;
Static methods for determining chewing efficiency are used during a direct examination of the oral cavity, when the condition of each tooth and all available ones is assessed and the data obtained are entered into a special table in which the share of each tooth in the chewing function is expressed by the corresponding coefficient. Such tables have been proposed by many authors, but in our country the methods of N.I. Agapov and I.M. Oksman are more often used.
In the table of N.I.Agapov, the lateral incisor of the upper jaw was taken as a unit of functional efficiency (Table 4).
In total, the functional value of the dentition is 100 units. The loss of one tooth in one jaw is equated (due to the dysfunction of its antagonist) to the loss of two teeth of the same name. Table 4 (according to N.I. Agapov) does not take into account the wisdom teeth and the functional state of the remaining teeth.
Table of coefficients of teeth by N.I.Agapov
Upper and lower jaw teeth |
Amount in units |
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Coefficients (in units) |
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I.M. Oksman proposed a table for determining the chewing ability of teeth, in which the coefficients are based on taking into account anatomical and physiological data: the area of the occlusal surfaces of the teeth, the number of tubercles, the number of roots and their sizes, the degree of atrophy of the alveoli and the endurance of the teeth to vertical pressure, periodontal condition and reserve forces of non-functioning teeth. In this table, the lateral incisors are also taken as a unit of chewing efficiency, the wisdom teeth of the upper jaw (three-cusp) are estimated at 3 units, the lower wisdom teeth (four-cusp) - at 4 units. In total, 100 units are obtained (Table 5). The loss of one tooth entails the loss of the function of its antagonist. In the absence of wisdom teeth, 28 teeth should be taken as 100 units.
Taking into account the functional efficiency of the chewing apparatus, a correction should be made depending on the condition of the remaining teeth. With periodontal diseases and tooth mobility of I or II degree, their functional value is reduced by a quarter or half. With tooth mobility of the III degree, its value is zero. In patients with acute or exacerbated chronic periodontitis, the functional value of the teeth is reduced by half or equal to zero.
In addition, it is important to take into account the reserve forces of the dentition. To take into account the reserve forces of non-functioning teeth, the percentage of loss of chewing ability in each jaw should be additionally noted as a fractional number: in the numerator - for the teeth of the upper jaw, in the denominator - for the teeth of the lower jaw. An example is the following two dental formulas:
80004321
87654321
12300078
12345678
80004321
00004321
12300078
12300078
In the first formula, the loss of masticatory ability is 52%, but there are reserve forces in the form of non-functioning teeth of the lower jaw, which are expressed by designating the loss of masticatory ability for each jaw as 26/0%.
With the second formula, the loss of chewing ability is 59% and there are no reserve forces in the form of non-functioning teeth. Loss of chewing ability for each jaw separately can be expressed as 26/30%. The prognosis for the restoration of function in the second formula is less favorable.
To bring the static method closer to clinical diagnostics, V.K. Kurlyandsky proposed an even more detailed scheme for assessing chewing efficiency, which was called an odontoperiodontogram. A periodontogram is a diagram-drawing in which data about each tooth and its supporting apparatus are entered. Data in the form symbols resulting from clinical examinations, X-ray studies and gnatodynamometry are entered in a special drawing scheme.