JP2900947B2 - Artificial bolus containing functional fine particles for evaluation of masticatory function - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an artificial bolus containing functional fine particles for evaluating a masticatory function.

2. Description of the Related Art It can be said that objectively grasping the masticatory function is a fundamental issue of dentistry. Although much research has been done on this in the past, the only method that quantitatively evaluated the ability to chew food in a state close to natural mastication was the measurement method of masticatory efficiency.

Problems to be Solved by the Invention The result of chewing food is considered as crushing in engineering. Grinding is essentially a repetition of destruction, which usually originates from sites where the uniformity of the material composition is disrupted. For this reason, this turbulence complicates the pulverization mechanism, making it difficult to quantitatively grasp it.

 There are, in particular, the following problems in understanding grinding. That is: 1) The pulverization changes for each food.

2) The grinding itself is difficult to quantify.

From the above two problems, the conventional measuring method of masticatory efficiency cannot be said to be the optimal method in terms of universality and reproducibility.

Object of the present invention It is an object of the present invention to provide an artificial bolus containing functional fine particles for evaluating a masticatory function capable of quantitatively measuring a masticatory ability.

SUMMARY OF THE INVENTION The present invention is not only crushed by occlusal pressure,
The gist of the present invention is an artificial bolus containing functional microparticles for evaluating a masticatory function, characterized by containing a large number of substantially uniform spherical functional microparticles for evaluating a masticatory function.

The best example of functional microparticles for evaluating masticatory function is microcapsules compressed by occlusal pressure. Also, an optimal example of an artificial bolus is polyisobutylene, for example, a commercially available chewing gum.

Examples In the pulverization engineering, the pulverization process includes a “particle size distribution function” representing a particle size distribution after crushing of particles (pulverization of a single particle) and a “selection function” which is a probability that each of these particles is further crushed. Analyzed in combination.

Therefore, the present inventor first applied this to the problem of quantifying the compression ability of mastication,
The relationship between the load and the deformation of the masticated particles was quantitatively grasped, and then the conditions of the artificial bolus and the conditions for simplifying the particle size distribution function and the selection function were examined.

By giving the particles the functional property of "crushing but not crushing", the "particle size distribution function" can be changed to "the relationship between load and deformation on the particles".

As for the “selection function”, the particle diameter is made minute and uniform in order to obtain “the probability of each particle being constant and invariable”.

From the above, it is possible to quantify the compressibility of mastication by taking the compression load acting on the artificial bolus from the sum of the compression deformation of the fine particles contained therein. In addition, the compression energy of mastication acting on the artificial bolus can be evaluated.

In order to provide uniform spherical particles with the mechanical properties of `` crushing but not crushing '', and to be able to reflect the tightness of the occlusal in the quantitative value, the diameter of the particles to be chewed should be as small as possible. desirable.

Considering the relationship between the physiological tooth movement during mastication (about 100 μm) and the particle size, a particle size of about 200 μm is appropriate.

The number of particles contained in the artificial bolus should be as large as possible to stabilize the quantitative value stochastically. In order to enable mastication, the particles are mixed into an adhesive substrate (polyisobutylene)
The property as a bolus is given to this.

As the functional fine particles to be chewed, it is preferable to employ microcapsules, for example, spherical polycarbonate microcapsules (hereinafter simply referred to as capsules).

Preferably, the capsule has the property of being crushed from a spherical shape to a flat shape without being crushed by chewing, and thereafter maintaining the flat shape. In this case, the capsule wall film is made of a tough polycarbonate film to prevent crushing during mastication and to prevent perforation of the wall film. In addition, in order to adjust the hardness of the capsule and maintain its shape after crushing, it is desirable to enclose a coarse starch as a content therein.

Capsules are made by underwater drying method, then JIS standard,
The particle diameters are made uniform using stainless steel sieves with openings of 177 μm and 210 μm.

The capsule group is mixed with the adhesive polyisobutylene to produce a chewing gum-like artificial bolus.

Thus, the artificial bolus is composed of two components, a capsule group and a chewing gum.

The preferred particle size of the capsule is distributed in the range of 193.5 μm ± 8.5%.

The preferred number of particles contained in the artificial bolus (hereinafter referred to as the total number of particles) is about 8.10 × 10 ⁴ (pieces).

Capturing the "relationship between load and deformation in the capsule" quantitatively, the relation between the load and deformation of the capsule becomes a monotonically increasing curve with good reproducibility.

The size of the artificial bolus is optimally 12.0 mm in diameter when spherical, considering the ease of mastication. It is always a lump during chewing, does not have a problem with sticking to teeth, and has a constant hardness (close to commercial chewing gum after 300 chewings).

Furthermore, the artificial bolus is tasteless, odorless and has good preservability.

 Hereinafter, an example of the compression capacity determination method will be described.

As a rule, on one side only to chew the meat each time
Chew 100 times.

After extracting the group of artificial bolus capsules after mastication, the capsules are sorted into crushed capsules (hereinafter referred to as flat capsules) and non-crushed capsules (hereinafter referred to as spherical capsules) and analyzed.

The artificial bolus is immersed in the organic solvent n-hexane, and the polyisobutylene of the gum component is completely dissolved to extract only the capsule group.

In order to reflect the average occlusal pressure at the time of mastication when sorting flat capsules, the criteria for selecting flat capsules are those with a minor axis of 125 μm or less.

A flat capsule and a spherical capsule are sorted by using a difference in the minor diameter between the two, using a sorter having a 125 μm slit-shaped sieve. Due to the low efficiency of the sorter, these sorts are performed by sampling 1/10 of the total number of particles.

First, in the artificial bolus after chewing t times, the ratio of the number of flat capsules to all capsules is defined as the flat capsule ratio p (t), and the product of this value and the total number of particles is the number of flat capsules n
(T), then the flat capsule ratio p after one mastication
Two values of (1) and the number of flat capsules n (1) are calculated, and these are set as compression capacity values (that is, the flat particle ratio and the number of flat particles).

As the microcapsules used in the present invention, various types other than the above examples can be adopted. For example, in addition to the particle diameter of 177 to 210 μm described above, those having a diameter of 88 to 177 μm for adult maloccluders, those having a diameter of 210 to 350 μm for deciduous occlusal patients or patients with dentures, periodontal disease For patients, there is one with a diameter of 350 to 550 μm.

On the other hand, as the wall film, in addition to polycarbonate, softer plastics such as AS resin (styrene / acrylonitrile copolymer resin), PS resin (polystyrene)
There are also those that use such.

Experimental example Deformation process in pulverization In pulverization engineering, the “particle size distribution function” that represents the particle size distribution after crushing particles (crushing of single particles is referred to as crushing), and “selection”, which is the probability that each of these particles is further crushed. Combined with the function, the crushing process is analytically captured.

The particle size distribution function is determined by the properties of the crushing material and the load conditions, while the selection function is determined by the crushing mechanism, the properties of the crushing material, the particle size, and the like.

Therefore, in order to apply the above crushing process to the task of quantifying the compressibility of mastication,
The relationship between the load and deformation of the particles was quantitatively grasped, and then the conditions of the artificial bolus for this purpose and the conditions for simplifying the particle size distribution function and the selection function were examined.

The load and deformation of the particles give mechanistic properties that they are "crushed but not crushed". In this way, the particle size distribution function can be changed to the relationship that the particles are crushed by being loaded, that is, the above-mentioned “relationship between load and deformation of particles”. In this way, the compression load acting on the particle can be directly obtained from the deformation amount of the particle.

The artificial bolus is composed of a group of spherical particles having the above characteristics, so that no matter how the artificial bolus is deformed by the load, each particle is deformed only in the compression direction. In this way, the load on the artificial bolus due to mastication is obtained as the total amount of deformation of each particle in the compression direction.

On the other hand, with regard to the selection function, the particle diameter is made minute and uniform in order to obtain “the probability that each particle is constant”. Thereby, the probability of each particle being bitten can be made substantially constant and unchanged throughout each chewing cycle during mastication.

From the above idea, the determination of the compressibility of mastication is based on the load applied to the artificial bolus from the sum of the compressive deformation of the spherical fine particles contained therein.

In addition, based on the relationship between the load and deformation of the particles,
The compression energy of mastication is also evaluated. That is, the compression energy of the mastication applied to the artificial bolus is obtained from the total energy obtained by integrating the compression load applied to each particle in the deformation direction.

Conditions for preparing artificial bolus The following conditions were used for producing an artificial bolus.

1) Mechanical properties Uniform spherical fine particles are provided with mechanical properties such as "only crushed but not crushed".

2) Particle size The particle size should be as small as possible for the purpose of reflecting the tightness of the occlusion in the quantitative value.

However, in order for the particles to be crushed by the average occlusal pressure during mastication, a certain size is necessary in consideration of the relationship between the physiological tooth movement during mastication and the particle diameter. Since the amount of this kind of fluctuation is about 100 μm, it is necessary that the minor axis of the particle when crushed is larger than this value.

 Therefore, the optimal particle diameter was considered to be about 200 μm.

3) Number of particles The number of particles contained in the artificial bolus should be as large as possible to stabilize the quantitative value stochastically.

The phenomenon of crushing particles is taken as a binomial distribution, and the number of particles is set to 10,000 or more in order to suppress the coefficient of variation when the expected value is assumed to be 50% to about several percent.

4) Properties as a bolus Particles do not dissipate during mastication, and give the artificial bolus a constant, constant chewability and so-called ease of feeding,
In order to enable chewing to be almost natural, the particles were mixed into an adhesive base material (polyisobutylene which is a component of a commercially available chewing gum) to form an artificial bolus, which was given properties as a bolus.

Thereby, the probability that the particles are bitten can be made constant during each chewing cycle during chewing.

Production of Microcapsules As an optimal example of the microcapsules, spherical polycarbonate microcapsules (hereinafter, simply referred to as capsules) produced by an underwater drying method were employed.

1) Mechanical properties of the capsule The capsule satisfies the requirements for the mechanical properties of the particles, that is, it crushes from a spherical shape to a flat shape without being crushed by chewing, and in addition, has the property of maintaining its flat shape thereafter. I did it.

In other words, in order to prevent crushing during mastication as well as to prevent perforation of the wall membrane, the capsule wall membrane is made of polycarbonate having excellent mechanical properties to provide a tough coating.

In this way, when the capsule is crushed by chewing, the dissipation of the contents can be completely prevented, and before and after the crushing, the total weight of the capsules as well as the individual weights become unchanged.

In addition, cornstarch was enclosed as a content in the capsule in order to adjust the hardness of the capsule and maintain the shape after crushing.

The reason for choosing corn starch is that the particle size of the capsule is 200 μm, the particle size is 2 to 10 μm, which is an appropriate size as the contents, and the property of being insoluble in organic solvents is that of the capsule. Facilitating fabrication,
In addition, its chemical chromogenic potential has the potential to be applied to capsule analysis.

2) Preparation of capsule A capsule was prepared by an underwater drying method. This is the first
It consists of two stages as shown.

First Step (Primary Dispersion) The contents of the capsule (corn starch) were dispersed in an organic solvent (dichloromethane) in which the wall material (polycarbonate) of the capsule was dissolved.

Second stage (secondary dispersion) Further, these are dispersed drop-wise in an aqueous solution of a surfactant (Tween 20, manufactured by Wako Pure Chemical Industries, Ltd.) as a medium for encapsulation, and the organic solvent is evaporated in this state. A wall material was deposited around the contents to form a wall film, and a capsule was produced.

(A) Preparation Corn Starch Treatment Corn starch was treated so as to be well dispersed in the primary dispersion medium and to be compatible with the capsule wall material.

To 100 g of coarse starch, 0.1 ml of Tween 20 (nonionic hydrophilic surfactant, polyoxyethylene (20) sorbitan monolaurate: HLB value 16.7) and distilled water were added.
The well-stirred one was ground to a powder.

Preparation of primary dispersion medium As the primary dispersion medium, 100 ml of organic solvent dichloromethane was used.
In contrast, a solution prepared by dissolving 10 g of polycarbonate (Panlite, manufactured by Teijin Chemicals Ltd.) as a wall material was prepared.

As a secondary dispersion medium, 75 ml of Tween 20 in a 500 ml beaker
Then, distilled water was added thereto to prepare a 500 ml aqueous solution.

(B) Primary dispersion 10 ml of a polycarbonate solution (primary dispersion medium) in a 30 ml beaker, 1 g of corn starch was added, and these were stirred with a magnetic stirrer to sufficiently disperse (primary dispersion). ). At this time, the rotation speed was set such that the stirrer was below the liquid level so that bubbles were not generated in the solution.

(C) Secondary dispersion and microencapsulation The solution (secondary dispersion medium) is stirred at high speed (1200 times / minute) by a magnetic stirrer having a heating function,
The solution primary-dispersed in (B) was added little by little to this, and further dispersed to form an [o / w] emulsion (secondary dispersion).

In this state, gradually raise the temperature and raise the temperature from room temperature to 40 ° C in about 30 minutes, then maintain this temperature for about 2 hours to adjust the evaporation of dichloromethane to deposit polycarbonate around the corn starch Then, a wall film was formed (microencapsulation).

The capsules were left at room temperature in the dispersion medium for at least one day in order to completely evaporate the dichloromethane.

(D) Dispersion and preservation of capsules The particle diameters of the capsules were adjusted using a stainless steel sieve having JIS standards and openings of 177 μm and 210 μm (classification).

The classification was performed by washing the capsules with a secondary dispersion medium. When classifying capsules made of the secondary dispersion medium used several times, they may be aggregated due to static electricity and classification may not be possible. This was prevented by forcibly vibrating the capsule.

After the classified capsules were dried naturally, they were stored at room temperature.

In the microencapsulation, the amount of the drug and the size of the beaker are factors that determine the rheological properties of the liquid, and it was necessary to faithfully perform all processes under the above conditions. .

3) Preparation of artificial bolus A capsule group having a volume of 0.5 ml (0.3417 ± 0.0001 g) weighed with a weighing device was converted into an adhesive polyisobrene (a product of Exxon Chemical Co., Vistanexx LMMS), which is a component of a commercially available chewing gum. ) The mixture was mixed with 0.5 g to prepare a chewing gum-like artificial bolus.

Examination of artificial bolus The preparation conditions of the produced artificial bolus were examined for each item.

1) Properties of Capsule (A) Particle Size As a result of screening by two successive sieves having openings of 177 μm and 210 μm, the particle size of the capsule is 193.5 μm ± 8.5%
Range.

Since the target particle size was 200 μm, it can be said that the size and the variation satisfied the required conditions.

(B) Number of Particles The following method was used to measure the number of particles.

First, sandwich the artificial bolus between two glass plates,
m, and the density of the number of capsules per area was measured by observing this through a glass plate.
It was 18.8 pieces / mm ² (18.75 to 18.80 pieces / mm ² ).

Next, the volume of the artificial bolus was determined to be 905 mm ³ from the measured value of the spherical diameter of the artificial bolus of 12.0 mm (the variation was less than ± 0.05 mm).

Based on these two values, the number of particles contained in the artificial bolus was determined from the following equation, and was set as the total number of particles N.

N = (905 × 18.8) /0.210=8.10×10 ⁴ [pieces] This value sufficiently satisfies the condition that as many particles as possible are contained as a condition for the number of particles.

(C) Mechanical properties By making the capsule wall film made of polycarbonate,
Considering that this has the mechanical property of "crushing but not crushing", we decided to quantitatively capture "the relationship between load and deformation in the capsule".

In this method, the capsule is sandwiched between acrylic plates, and a compressive load is applied from the side, from 5 to 10 gw from 0 to 170 gw.
The minor axis of the capsule crushed at each load was taken on a stereoscopic microscope photograph, and these were measured and measured. As a result, no crushing of the capsule was observed during the measurement.

First, in a capsule having an average particle size of 194 μm, it was confirmed that there is a monotonically increasing curve relationship between load and deformation with good reproducibility, as shown in FIG.

Next, a capsule having a minimum diameter of 178 μm and a maximum diameter of 210 μm was added to examine this relationship. As shown in FIG. 3, a difference presumed to be due to a difference in particle diameter (193.5 μm ± 8.5%) was confirmed.

From this figure, it can be seen that the minor axis of the crushed capsule is 8 mm after the load is removed, regardless of the original particle diameter and the deformation amount at that time.
It was also confirmed to return to μm.

Therefore, it was confirmed that the capsule satisfied the conditions for the mechanical properties of the particles.

2) Properties of the occlusal sample The artificial bolus containing the capsule, which has been confirmed to satisfy the conditions for the particles, satisfies the conditions for the artificial bolus, which are constant and easy to bite and send as a bolus. In order to confirm whether this is the case, the following examination was added.

(A) Mechanical properties The hardness of the artificial bolus was taken as the viscosity in the field of rheology, and the viscosity was measured as a parameter indicating the hardness.

Viscosity is a kind of friction that hinders the flow inside a fluid, and viscosity is a physical constant indicating its degree. Therefore, it was thought that the hardness of an artificial bolus could be obtained by measuring this.

The viscosity is determined from the deformation rate when an artificial bolus is filled between two parallel disks having a radius r in a device referring to a parallel plate plastometer as shown in FIG. I asked. At this time, the viscosity η was determined from the following equation that is established between the constant load P, the time t, the viscosity η, the radius r of the circle, and the distance H between the disks (H ₀ is an initial value).

Pt = (3πηr ^4/4 ) × (1 / H ² −1 / H ₀ ² ) The measurement conditions were P = 1 kgw (constant load by weight), r = 7.5 mm, and temperature 37 ° C.

FIG. 5 shows the viscosity of the artificial bolus after chewing 0 times, 100 times, 200 times, and 300 times. The viscosity of a commercially available chewing gum is also shown for reference.

As shown in FIG. 5, since the viscosity of the artificial bolus did not change upon mastication, it was confirmed that the artificial bolus maintained a constant hardness during mastication. This property is considered to be due to the stability of the artificial bolus gum component polyisobutylene to saliva.

In contrast, commercial chewing gum is hard before chewing,
When it began to chew, it softened rapidly, and after about 10 chews, it began to harden, and then hardened. This property was presumed to be due to the fact that sugar, which accounts for about 80% as a component, was rapidly dissolved in saliva at the start of chewing and then gradually eluted from the gum.

In addition, the artificial bolus has hardness close to that of a commercially available chewing gum after chewing 300 times, and thus satisfies the hardness as a bolus.

On the other hand, from the experience of 11 subjects, it was confirmed that the artificial bolus was always one mass at the time of mastication, and that there was no problem with sticking to teeth unless there was a bad inlay.

The size of the artificial bolus is the size of a commercially available gum, that is, 3 mm of the front and rear, 11 mm and 13 mm, centering on a spherical diameter of 12 mm.
The ease of mastication was compared for the species, and the best spherical diameter was 12.0 mm.

(B) Taste and smell The components of the artificial bolus are tasteless, odorless corn starch,
Polycarbonate and polyisobutylene, and the artificial bolus was tasteless and odorless.

(C) Preservability When the artificial bolus was refrigerated in water and the capsules were stored in a dry state at room temperature, the former was one year and the latter was two.
There was no change in the properties after the lapse of years. From this, it was confirmed that the storage stability was good.

From the examination results of the above three items, it was confirmed that the artificial bolus satisfies the conditions of constant easiness of chewing and ease of feeding as a bolus, and enables natural chewing during measurement.

Compressibility determination method 1) Chewing method An artificial bolus was given to a subject, and chewing was performed 100 times in principle on one side to the extent that the meat was chewed each time.

2) Analysis method First, the gum component of the artificial bolus after mastication was removed to extract a capsule group. Next, the capsules were sorted into crushed capsules (hereinafter, referred to as flat capsules) and uncrushed capsules (hereinafter, referred to as spherical capsules) and analyzed.

(A) Extraction method of capsule group The artificial bolus chewed by the subject was taken out of the oral cavity, immersed in an organic solvent n-hexane, and polyisobutylene as a gum component was completely dissolved to extract a capsule group. Note that n-hexane is an organic solvent that dissolves only polyisobutylene and does not dissolve the capsule group.

(B) Criteria for selecting a flat capsule group In selecting a flat capsule, it is necessary to set a selection criterion.

Therefore, I made the following estimation. To reflect the average occlusal pressure during mastication on this criterion,
A value of about 2.0 kgw / mm ² was obtained. When this was converted to the load per capsule based on the density of the number of capsules above,
106 gw / piece.

On the other hand, when the same load was applied to a capsule having an average particle diameter of 194 μm, the minor axis after load removal was about 125 μm from the relationship between the load and deformation of the capsule in FIG.

From the above results, the criteria for selecting flat capsules were those having a minor axis of 125 μm or less.

(C) Sorting method of flat capsules Using a sorter having a slit-shaped sieve in accordance with a sorting criterion of 125 μm, flat capsules and spherical capsules were sorted by utilizing the difference in minor diameter between the two. In addition, since the efficiency of the sorter was low, these sorts were performed by sampling about 1/10 of the total number of particles.

First, 1/10 of the extracted capsule group was immersed in n-hexane, put into a sorter, and then combined with the forced vibration of the capsule by ultrasonic waves, only the flat capsules were sorted by passing through the slit. .

(D) Capsule during mastication The dynamics of the capsule during mastication were examined for the following three points.

How to crush inside artificial bolus To examine how the capsule is crushed during chewing, sandwich the artificial bolus after chewing 0 times and 300 times between glass plates,
When the morphology of the inner capsule was examined with a stereoscopic microscope while compressing to m, no change was observed in these. From this, it was confirmed that when a flat capsule was formed, this was due to direct crushing.

Also, to investigate the change of the flat capsule during mastication,
After sorting, only the flat capsules were mixed with polyisobutylene and chewed 20 times and then sorted again. As a result, all the capsules were determined to be flat capsules, and it was confirmed that the flat capsules did not return to a spherical shape by mastication.

From the above two points, it was confirmed that the flat capsule corresponds to a record of the fact that the capsule was directly crushed between the teeth of the opposite jaw, and this did not disappear again.

Dissipation of contents For the purpose of investigating the dissipation of capsule contents due to mastication, first, the weight of a prescribed amount of capsule group contained in the artificial bolus was measured in advance, and then the artificial bolus containing these was weighed 100 times. After mastication, the capsule group was extracted and weighed again.These values were 0.3416 before and after mastication.
g to 0.3418 g, a slight increase by 6 / 10,000. This increase is considered to be due to the adhesive remaining on the capsule surface.

Therefore, it can be considered that there is at least no dissipation of the capsule contents by mastication.

From the above, it was confirmed that the weight did not change before and after the spherical capsule became a flat capsule.

Dissipation from artificial bolus To examine the number of capsules that dissipate from the artificial bolus during mastication, three subjects masticated the artificial bolus 100 times, then took them out and washed them well. The number of particles was measured to be 2 to 4.

Therefore, considering the total number of particles, the influence of the deviating particles on the quantitative value can be ignored.

From the results of the study on the artificial bolus described above, it can be said that the artificial bolus (microcapsule-containing chewing gum) of the present invention faithfully represents the compressibility.

In addition, if the incidence rate of flat capsules is considered as the problem of instantaneous failure rate in probability theory, the probability that a single capsule is bitten is considered to be constant during each mastication time during mastication. It can be said that it follows an exponential distribution.

3) Calculation method of compression capacity value (A) Definition of compression capacity value First, in the artificial bolus after t times of chewing, the ratio of the number of flat capsules to all capsules (spherical capsule and flat capsule) is determined by the flat capsule ratio p (t ), And the product of this value and the total number of particles is defined as the number n (t) of flat capsules.

Next, from the viewpoint of universality, the expression of the compressibility of mastication is preferably a ratio at which the capsule is crushed after one chewing (that is, a flat capsule ratio after one chewing). On the other hand, from the viewpoint of specificity, the number of capsules crushed after one chewing (that is, the number of flat capsules after one chewing) is clinically useful.

Therefore, in this experiment, the flat capsule ratio p after one mastication
Two of (1) and the number n (1) of flat capsules after one chewing were defined as a compressibility value, that is, a flat particle ratio and a flat particle ratio.

(B) Calculating Method of Compressive Capacity Value Calculate the volume ratio from each weight of the flat capsule and the spherical capsule extracted from the artificial bolus after t times of mastication, and calculate the compressive capacity value in consideration of the exponential distribution described above. It was calculated by the formula.

Total number of particles: N = 8.10 × 10 ⁴ [pieces] Flat capsule rate after t times of chewing: p (t) = weight of flat capsule / weight of all capsules Compressibility value: flat particle rate: p (1) = 1 − (1-p (t) ^{1 / t} number of flat particles: n (1) = p (1) × N [pieces] Trial results and consideration of compression capacity determination method For those in their twenties without dental disease and jaw movement disorder The compression ability determination method was tested on 11 male and female subjects, including 5 males with normal individual occlusion as normal occlusion subjects.
There are four females and four females, and the malocclusion includes an angle II class 1 female with molar teeth biting cusp-to-cusp, and an angle III male 1 with open jaw due to jaw deformity
People.

1) Trial results Tables 1 and 2 show the percentage of flat capsules after mastication obtained in the trial of this quantitative method. Based on these results, the flat particle ratio and the number of flat particles were calculated, and the intra-individual and inter-individual fluctuations in the number of mastications, the flat capsule ratio, and the compressibility were examined.

a) The number of mastications and the rate of flat capsules When the same subject (A) tried 100, 200, and 300 times of chewing, the rate of flat capsules changed according to the distribution coefficient of the exponential distribution, as shown in FIG. t-test, risk factor 1%).

Accordingly, it was confirmed that the formula for calculating the compression capacity was satisfied.

b) Intra-individual variation of compression ability value In the same subject (A), a variation coefficient was calculated in order to examine the intra-individual variation of the compression ability value when 100 times of mastication were tried five times. The coefficient of variation is calculated by standard deviation / average. As a result, the coefficient of variation was 4.24% for both the flat particle ratio and the flat particle number (Table 3).

C) Inter-individual variation of compression capacity value The compression capacity values of 11 subjects are shown in Table 4 and FIG.

As shown by these compression ability values, the values of normal occluders ranged from 106 to 321 in terms of the number of flat particles, and the ratio of the minimum value to the maximum value was distributed over a wide range of 1: 3.0. The values for boys were higher than those for girls.

The value for angle II class 1 girls was 55, less than half that of normal occlusion.

The value of angle class III open bite males was 44, less than one third of normal male bite.

2) Discussion (A) Regarding compression capacity value Exponential distribution Chewing was captured not in the pulverization of food but in the compression process of artificial bolus. On the other hand, it was confirmed that the flat capsule ratio after mastication followed the exponential distribution, and it can be said that the compressibility determination method faithfully grasps the mastication function.

Intra-individual variation Since the intra-individual variation of the compression ability value is small, it is considered that these certainly represent the compression ability of each individual chewing.

Inter-individual variation This indicates that the difference in compression ability of mastication between individuals is clearly captured because of the large inter-individual variation in compression capacity.

From the above, it can be said that the compressibility measurement method is a new clinically useful evaluation method of masticatory function.

(B) Mathematical Interpretation of Compressive Capacity Quantitative Method Regarding the compressive capacity quantified method, mathematical viewpoints concerning exponential distribution, compressive capacity value, intra-individual variation of compressive capacity value, and mastication compression energy and occlusal contact area Considered from.

Exponential distribution and compression capacity value The reason why the flat capsule ratio follows the exponential distribution, that is, the distribution function of the exponential distribution, is considered from the following two mathematical viewpoints.

a) Probabilistic interpretation The fact that the flat capsule ratio p (t) after t times of mastication follows the distribution function of the exponential distribution means that, assuming that λ is a constant, p (t) = 1−exp (−λt )... Equation 1 holds.

 If this expression 1 is changed to an easy-to-understand form, 1-p (t) = exp (-λt) Expression 1 'is obtained.

Note that exp (−λ) is the flat particle ratio of the compressibility value.

By the way, when both sides of Expression 1 are differentiated by t, a probability density function, dp (t) / dt = (λexp (−λt)) Expression 2 is obtained. This indicates the probability density existing in the minute section dt. In the exponential distribution, the right side of Equation 2 is represented by (1-p
The value divided by (t)) is expressed as (λexp (−λt) / exp (−λt) = λ... Rule 1 constant λ from Equation 1 ′ as follows.

Therefore, from Law 1, the ratio of the number of particles newly made into a flat capsule per chewing to the number of particles in a non-flat capsule (spherical capsule) at that time may be constant during mastication during each mastication. Proven.

b) Geometric interpretation The exponential distribution was simplified and interpreted by expressing it as shown in Fig. 8 based on a geometric triangular pattern called Sirpinski gasket.

First, in the triangular pattern, the capsules contained in the artificial bolus were two colors, ie, white was a non-flat capsule and black was a flat capsule, and the number of particles thereof was made to correspond to the area of the triangle. As the first stage, after 100 times of chewing, 1/4 of all capsules are chewed into flat capsules, and if 3/4 remain uncrushed, 1/4 of white triangles become black. Therefore, the flat capsule ratio can be expressed as follows.

Next, as the second stage, chew 100 more times, for a total of 2
The flat capsule ratio after mastication 100 times can be expressed as follows, assuming that this follows an exponential distribution, since 1/4 of a white triangle is always black from Law 1.

Note that the area of the white triangle, that is, the ratio of the number of non-flat capsules changed by 3/4, the ratio after 0 times of mastication is (3/4) ⁰ (= 1) after 100 times of mastication After chewing (3/4) ¹ (= 3/4) 200 times, it can be expressed as (3/4) ² (= 9/16), and if T is a natural number indicating the stage, , (3/4) ^T

If this is expressed according to Expression 1 ′, 1−p (T) = (3/4) ^T Expression 3 where T = t / 100. This corresponds to equation 1 ′, and / 4 corresponds to λ in rule 1. Note that the value of λ obtained from Equation 3 and Equation 1 ′ is −ln
(3/4), (≒ 0.288), which is different from 1/4, but this is 1
This is because the number of mastication every 00 times is targeted, and when the value of T is reduced, these become equal in the limit.
From this equation, it was confirmed that the flat capsule ratio due to the triangular pattern follows an exponential distribution.

Furthermore, in interpreting the meaning of the exponential distribution, overlapping black triangles in a triangular pattern does not affect white triangles, so this is given as a condition.

Under this condition, considering the case where the compressibility is constant, that is, the probability of the capsule being bitten for each mastication is constant, the flat capsule ratio at this time is always 1% of the entire triangle at each stage. It can be simply expressed that / 4 becomes black. This means that every minute portion of the triangle becomes black at the same ratio at each stage, so that attention is paid to the white portion, and it can be seen that Equation 3 holds.

Therefore, it was proved geometrically that the flat capsule ratio follows an exponential distribution when the compressibility is constant during each mastication.

As described above, stochastically and geometrically considering that the flat capsule ratio followed the exponential distribution, the compression capacity quantification method
As expected, it was demonstrated that the constant compression ability was captured throughout each chewing cycle.

Coefficient of Variation of Compressibility Value The coefficient of variation of the compressibility value in the trial result was 4.24%, but the relationship among the total number of particles N, the number of chewing times t, the flat particle ratio p (1), and the sampling ratio s was 2 By approximating the term distribution,
The theoretically estimated coefficient of variation was determined from the following equation.

 The theoretically estimated coefficient of variation is as follows.

[{Np (1) (1-p (1)} ^1/2 / Np (1)] x (1 x t1 ^{/ 2} ) x (1 / s1 / ² ) Although this value was 2.51% Since the difference between this and the value of the trial result was as small as 1.73%, the reliability of the compression capacity determination method was also confirmed stochastically.

According to the above equation, the amount of change becomes smaller in proportion to t ^1/2 , that is, the square root of the number of times of mastication. Based on this formula, we estimate the coefficient of variation when the number of mastications in the quantitative method is changed, and compare it with the value of 4.24% for 100 chews of the trial result. On the contrary, if it is reduced to 50 times, it is estimated that it will increase to 5.98%. On the other hand, from the experience of 11 test subjects, considering fatigue, 100 clinical trials are considered appropriate.

In addition, according to the same equation, it is considered that the above fluctuation amount is apparently (1 / s ^1/2 ) times larger than the true value due to the influence of the sampling described in the selection section. Therefore, if all the capsules are sorted by increasing the sorting efficiency, these can be reduced to about 1/10 ^1/2 times.

If the compressive energy and the occlusal contact area of the mastication can be quantified, the compressive energy of the mastication can be evaluated based on the relationship between the load and the deformation of the particles, as described above. That is, the compression energy at the time of one-side mastication (referred to as compression energy of mastication) can be calculated from the compression capacity value.

At the same time, based on the density of the number of capsules described above, an occlusal area (referred to as an occlusal contact area) that functions to compress the capsule during one-side mastication can be calculated from the compressibility value.

In addition, two types of energy required for compression of the artificial bolus and compression of the capsule group can be considered for chewing, but the former is about 5% of the latter when estimated from the viscosity of the artificial bolus. Since it depends on the speed of movement, it was excluded from the calculation.

First, based on the relationship between the load and the deformation in the capsule of FIG. 3, the load is integrated by the working distance as shown in FIG. 9, and the energy required for deformation of the flat capsule is calculated for each particle diameter. The average of these was determined to be 4.5 × 10 ⁻⁵ J / piece.

From the product of this value and the number of flat particles, the compression energy of mastication was determined (Table 5).

Further, the occlusal contact area was determined from the product of the reciprocal of the capsule density of 0.532 mm ² / piece and the number of flat particles (also Table 5).

For example, when the above calculation is performed for the median compression capacity value of five male normal occluders in this experiment, the compression energy of mastication is 9.45 × 10 ^-3 J and the occlusal contact area is 11.2 mm ² there were.

As for the occlusal contact area, the occlusal contact area of normal male occlusion by prescale was 11.74 m for the average of 11 persons
Since it has been reported that m ^2, and approximates the calculated values obtained.

By mathematically examining the compression capacity determination method as described above, it is possible to estimate the mastication compression energy and the occlusal contact area, including the coefficient of variation of the compression capacity value. It has usefulness or developmental potential.

Conclusion In this experiment, we aimed to quantitatively evaluate the compressibility of mastication when objectively evaluating the masticatory function.

For this purpose, first, the compression energy of chewing is captured by the compression deformation before the food is crushed, and chewing gum containing polycarbonate microcapsules is produced as an artificial bolus intended for this, and then compressed by this. A capacity quantification method was set up and tried.

According to the trial results obtained with 11 males and females in their 20s (6 males and 5 females), the intra-individual variation of the compression ability value was 4.24%.
On the other hand, the inter-individual variation was found to be as large as 1: 3.0 as a ratio of the minimum value to the maximum value in nine normal occlusion subjects.

Furthermore, by mathematically examining this method, the intra-individual variation, the compression energy of mastication and the occlusal contact area could be estimated.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a process for producing a capsule used in the present invention, FIG. 2 is a graph showing the relationship between load and deformation in capsules having the same particle diameter, and FIG. 3 is load in capsules having different particle diameters. Fig. 4 is a graph showing the method of measuring the viscosity of the artificial bolus, Fig. 5 is a graph showing the viscosity of the artificial bolus during mastication, and Fig. 6 is the number of times of mastication and flattening. Fig. 7 is a graph showing the relationship with the capsule ratio, Fig. 7 is a diagram showing the inter-individual variation of the compressibility, Fig. 8 is an explanatory diagram showing a geometrical interpretation method of the exponential distribution, Fig. 9 is the load and deformation in the capsule It is a graph which shows the relationship between quantity and energy.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) A61C 19/04 A61B 5/22 A23G 3/30 A61K 9/68

Claims (1)

(57) [Claims] (1) it is only crushed by occlusal pressure and is not crushed;
An artificial bolus containing functional microparticles for evaluating a masticatory function, characterized by containing a large number of substantially uniform spherical functional microparticles for evaluating a masticatory function.