RU2803485C1 - Method of sizing and configuration of the palate and fiber-optic scanner for its implementation - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: group of inventions can be used in dentistry to determine the configuration and dimensions of the palate in the diagnostics of a disease associated with abnormalities of the maxillofacial and oral cavity, primarily in children. The method of determining the size and configuration of the palate is as follows: with the help of an optical radiation source a luminous flux is formed, it is directed perpendicular to the surface of the palate along the vertical Y axis, using a radiation receiver, the luminous flux reflected from the palate is received, the intensity of which is used to determine the distance from the radiation source to the irradiated surface, the radiation source is moved along the y-axis to k-points at intervals ΔY of n-points along the X-axis at intervals ΔX, at each of the k-n-points, the values of the intensity of the light flux reflected from the palate are measured, by which the distance Z from the radiation source to the palate is determined in accordance with the normalized function of converting the intensity of the light flux from Z coordinate, a three-dimensional matrix of length is built, in accordance with which 3D model of the palate is made.

EFFECT: accurate determination of the shape and dimensions of the patient's palate with the help of the proposed fiber optic scanner of high precision that is easy to technically implement.

9 cl, 4 dwg

Description

The invention relates to measuring technology and can be used in medicine, namely in dentistry to determine the configuration and size of the palate when diagnosing diseases associated with anomalies of the oral cavity, maxillofacial pathologies, primarily in children. The main purpose is to use the measurement results to produce a 3D model of the oral cavity (for example, from patient-safe plastic), which will be installed on the membrane of the tongue pressure sensor on the palate and will ensure accurate positioning of the sensor in the oral cavity.

In the work [Uzhumetskene I.I., Research methods in orthodontics, M: ed. “Medicine” - 1970] provides information about various methods of measuring the height of the palate: “The diagnostic value of measuring the height of the palate was put forward by Simon. Using the gnathograph he described, the sagittal and transversal curve of the palate is transferred to graph paper. The curve of the palate can be transferred to graph paper, also using a Korkhaus symmetrograph with a cutting grid or with a draftsman. The cutting grid (a design proposed by van Loon) consists of a large number of thin metal rods, which, when the clamp is released, cuts the model in a sagittal or transversal direction, and the curve of the palate is transferred to graph paper using a sharp pencil. The draftsman immediately displays the curve of the palate graphically on graph paper.”

This method and the devices that implement them are very outdated, cause some inconvenience for patients, and in some cases are quite traumatic.

This method and the devices that implement them are very outdated, cause some inconvenience for patients, and in some cases are quite traumatic.

Currently, to determine the size and configuration of the palate in patients, dentists make impressions from various materials: elastic (analginate, silicone), thermoplastic, modeling, plaster [kosmetik-dent.ru].

Elastic materials reflect the relief of the oral cavity well, but are subject to shrinkage, so they are not used for long-term storage.

Silicone materials well preserve the image of all areas of the teeth, including the gingival areas. Used for the manufacture of clasp models and ceramic crowns.

The disadvantage of silicone materials is shrinkage, which occurs approximately an hour after taking an impression, so the technician must have time to make a plaster model during this time.

Plaster of Paris is usually used to make hard impressions.

Nowadays, plaster is rarely used, since the patient experiences discomfort when taking an impression, and it is also difficult to take an impression from areas of the teeth located close to the gums. Another disadvantage of gypsum is its uneven hardening: it crumbles when it dries, so it is often removed from the mouth in pieces.

Thermoplastic materials become soft when exposed to temperature and harden when cooled. Their disadvantages include possible deformations that occur when removing the mass from the oral cavity.

Modeling materials are medical wax containing paraffin and stearin. They accurately display fabrics and are easy to use.

The disadvantage is considered to be instability to temperature: when it increases, even slightly, they begin to melt.

The method of using the listed materials is as follows.

The material is mixed with a special spatula. The mass is placed in a spoon, inserted into the mouth, and the spoon is pressed against the alveolar process. If an imprint is taken from the upper jaw, pressure is applied first from behind, then from the front, and from the lower jaw - vice versa. The mass remains in the mouth for a certain time in order to record all the anatomical features of the oral cavity. The edges of the impression are formed by the movements of the patient's tongue and lips. Removing the impression from the oral cavity is done with one jerk to avoid deformation. The cast is washed with running water and immersed in a special solution, after which you can begin making a plaster model. The optimal time to create a model based on a print is the first 30 minutes, until the mass is deformed. The technician pours liquid plaster into the spoon, resulting in a diagnostic model of the jaw.

The disadvantage of this method of forming an impression is:

- low accuracy of determining the oral impression, which depends on several factors: the quality of the material, accurate execution of the method algorithm, correct performance of the actions by the patient;

- the procedure for obtaining physical impressions causes short-term discomfort in the patient due to the materials placed in the oral cavity on impression trays.

In addition to the above disadvantages, it should be noted that if the profile of a child’s oral cavity is determined, it is difficult to talk not only about the accuracy, but also about the possibility of implementing the method in general.

Intraoral (intraoral) 3D scanners are known - devices for creating digital impressions that project light onto the scanned object, receive the reflected light signal and transmit it to a computer to create a three-dimensional image [carestreamdental.com].

But such scanners cannot be used to determine the profile and size of the palate for several reasons:

- have overall dimensions exceeding the dimensions of the child’s cavity;

- difficulty in recognizing poorly visible areas: in some cases, when it is important for the doctor to position the edges of the prosthesis subgingivally, it may be more difficult for the light to correctly determine the entire exact line. Unlike conventional impression materials, light cannot physically separate the gum and therefore cannot scan “invisible” areas [qsttech.com];

- the sensitivity of optical signal conversion is low, since the reflective surface of the palate has a low reflection coefficient, and accordingly the accuracy of measuring distances to the palate is also low;

- most of them are designed to use complex software and complex secondary equipment;

- are not intended for measuring the geometric parameters of the oral cavity, but for obtaining an image; accordingly, they are not standardized according to the required metrological characteristics, primarily, according to the measurement range, the output signal range and the main and additional errors.

As a result of a search through sources of patent and technical information, no devices were found with a set of essential features that coincide with the proposed invention and provide the declared technical result.

The technical result of the proposed invention is an accurate determination of the shape and size of the patient’s palate, safe for the patient’s health, using the proposed high-precision fiber-optic scanner, which is easy to technically implement. In addition, it is possible to use the invention to determine the size and configuration of similar hard-to-reach narrow cavities in other areas of the national economy.

The technical result is achieved by:

- the method for determining the size and configuration of the palate is that using an optical radiation source, a light flux is formed, directed perpendicular to the surface of the palate along the vertical Z axis, and with the help of a radiation receiver, the light flux reflected from the palate is received, the intensity of which is used to judge the distance from the source radiation to the irradiated surface, and differs in that the radiation source is moved along the ordinate Y axis to k-points with intervals ΔY from n-points along the x-axis X with intervals ΔХ, at each of the k-n-points the intensity values of the light flux reflected from the sky are measured , by which the distance Z from the radiation source to the palate is determined in accordance with the normalized function of converting the intensity of the light flux from the Z coordinate, a three-dimensional matrix of length is constructed, in accordance with which a 3D model of the palate is constructed;

the irradiated surface of the palate is first temporarily normalized by reflection coefficient;

a fiber-optic scanner for determining the size and configuration of the palate, containing a radiation source and receiver, characterized in that it contains a base in which n-guides are made in the form of depressions with depth h and width b at intervals ΔX from each other, in which the body alternately moves , inside of which there is an optical system in the form of input and output optical fibers, with the first ends of the optical fibers parallel to the direction of movement of the housing, and their optical axes perpendicular to the illuminated surface, and the second ends of the input fiber and output fiber are connected to the radiation source and radiation receiver, respectively;

- the base can be made flat, convex, concave;

- the shape of the base can follow the shape of the surface on which it is installed;

- a microlens can be formed at the end of at least one optical fiber;

- the emitting end of the supply optical fiber can be located in the vicinity of the focus of the collecting lens.

In fig. Figure 1 shows a simplified design of a fiber-optic palate scanner; Fig. 2 - base with spherical depressions, in Fig. 3 - base with rectangular depressions, in Fig. 4 is a diagram explaining the principle of operation of the scanner and the scanning method.

The fiber-optic scanner contains a base 1, in which, at intervals ΔX from each other, n-guides are made in the form of depressions 2 with a depth h and a width b, in which a housing 3 moves with an optical system located inside it in the form of an inlet (POV) 4 and an outlet (OOB) 5 optical fibers (Fig. 1). The first ends of the optical fibers 4 and 5 located in the housing 3 are parallel to the direction of movement of the housing 3, and their optical axes are perpendicular to the illuminated surface (palate) 6 (Figs. 2 and 3). The second ends of the optical fibers 4 and 5 are connected to the radiation source 7 and the radiation receiver 8, respectively, located in the electronic unit 9 of the scanner, where electro-optical and photoelectric conversions are carried out (Fig. 4).

The depressions 2 in the base 3 can be cylindrical or rectangular. The shape and external dimensions of the housing 3 may coincide with the shape and external dimensions of the depressions 2 (see Fig. 2). It is also possible that the depressions 2 are rectangular and the body 3 is cylindrical (see Fig. 3). The dimensions and tolerances for the dimensions of the housing 3 and the depressions 2 must ensure that the housing 3 moves in the depressions 2 along a sliding fit, and the optical axes of the ends of the optical fibers 4 and 5 must be perpendicular to the illuminated surface 6 (see Fig. 1-3).

The upper and lower surfaces of the base 3 can be made flat, convex, or concave. In addition, the lower surface of the base 3 can follow the shape of the surface on which it is installed.

If it is necessary to increase the sensitivity of optical signal conversion, it is possible to use a focusing lens 10, which forms the necessary spatial distribution of the light flux from the output of the emitting end of the supply optical fiber 4.

A microlens may be formed at the end of at least one optical fiber.

The proposed method for determining the size and configuration of the palate using the proposed fiber-optic scanner is carried out as follows.

In one of the guides - cavity 2, a housing 3 is installed with the first ends of the POV 4 and OOV 5 fixed in it. The light flux from the radiation source (LED) 7 along the POV 4 is directed to the palate 6. The light flux reflected from the palate 6 enters the receiving end of the OOV 5 and is sent along it to the radiation receiver 8, where it is converted into an electrical signal. The body 3 moves along the first cavity 2 in the Y direction, respectively, at k-points with intervals ΔY, electrical signals (for example, current I) are collected from the output of the radiation receiver 8, proportional to the distances z _k1 from the radiating end of the POV 4 to the palate at these points. The measurement results are entered into the 1st term of the matrix of electrical signals, which, in accordance with equation (1), is converted into a length matrix:

where I _kn ,z _kn are the values of electrical signals at the scanning points and the corresponding distances from the body 3 to the palate 6; m is the proportionality coefficient.

Then the body 3 is moved along the second depression 2 in the Y direction, respectively, at k-points with intervals ΔY, electrical signals are taken from the output of the radiation receiver 8, proportional to the distances z _k2 from the radiating end of the POV 4 to the palate 6 at these points. The measurement results are entered into the 2nd term of the length matrix (1). This operation is repeated in each of the n-th guides. In accordance with the filled length matrix (1), 3D modeling of the profile of the palate is carried out and, if necessary, using the obtained dimensions, for example, using a 3D printer, a part is made that repeats the profile and dimensions of the patient’s palate. The resulting part can be used to measure the pressure of the tongue on the palate as part of a fiber-optic pressure sensor when identifying various maxillofacial pathologies.

To increase the accuracy of measuring the size and profile of the palate, it is necessary to reduce the intervals ΔY and ΔХ.

On the illuminated surface (palate) 6 it is advisable to temporarily apply paint or film normalized by reflectance coefficient (for example, a safe spray containing medical talc or flour used in dentistry).

During the scanning procedure, the surfaces of the scanner are wiped with a disinfectant.

We will establish the cause-and-effect relationship between the claimed features and the achieved technical effect as follows.

Making the base of the body 3 flat, convex, or concave is necessary to reduce the distance from the emitting surface of the POV 4 or lens 10 to the palate 6, which increases the sensitivity of optical signal conversion and, accordingly, the accuracy of measurement and determination of the profile and size of the palate 6.

The introduction of a focusing lens 10 into the design of the scanner is necessary to focus the light flux from the output of the emitting end of the POV 4, which provides an increase in the sensitivity of optical signal conversion if the distance to individual points of the palate 6 cannot be reduced by changing the shape of the base of the housing 3.

The formation of at least one optical fiber of a microlens at the end provides an increase in the sensitivity of optical signal conversion without introducing an additional lens 10, thereby helping to reduce the height of the device as a whole.

The movement of the housing 3 in the depressions 2 along a sliding or more rigid landing reduces the instrumental component of the error in measuring distances z.

Reducing the intervals ΔY and ΔХ reduces the methodological component of the error in measuring distances z.

The location of the first (emitting) end of the POV 4 in the vicinity of the focus of the collecting lens 10 ensures a reduction in the loss of light flux in the measurement zone, and, accordingly, an increase in the accuracy of measuring distances z.

Applying paint or film normalized by reflectance to the illuminated surface (sky) 6 is necessary to increase the accuracy and repeatability of measurement results.

The length of optical fibers 4 and 5 can be 2...200 m, which makes it possible to carry the electronic unit 9 away from the patient at a distance that is safe for his health.

The use of LEDs 7 instead of lasers makes it possible to reduce the power of optical radiation to 5...10 mW in the measurement area, which ensures absolute safety of the scanning procedure.

The technical result of the proposed invention is as follows.

The proposed method and the new design of the fiber-optic scanner make it possible to reduce inconvenience for patients, instrumental and methodological measurement errors, position the scanner in a small volume of the patient’s mouth, and use absolutely safe optical radiation with a power of no more than 10 μW, which excludes electromagnetic radiation in the patient’s oral cavity.

The proposed invention is a technical solution to a problem that is new, industrially applicable and has an inventive step, i.e. the proposed invention meets the patentability criteria.

Claims (9)

1. A method for determining the size and configuration of the palate, which consists in forming a light flux using an optical radiation source, directing it perpendicular to the surface of the palate along the vertical Y axis, using a radiation receiver to receive the light flux reflected from the palate, the intensity of which is used to judge the distance from the radiation source to the irradiated surface, characterized in that the radiation source is moved along the ordinate Y axis to k-points with intervals ΔY from n-points along the x-axis X with intervals ΔХ, at each of the k-n-points the intensity values of the light reflected from the sky are measured flows, from which the distance Z from the radiation source to the palate is determined in accordance with the normalized function of converting the intensity of the light flux from the Z coordinate, a three-dimensional matrix of length is constructed, in accordance with which a 3D model of the palate is constructed. 2. The method according to claim 1, characterized in that the irradiated surface of the palate is previously temporarily normalized by reflectance by applying paint with a known reflectance. 3. A fiber-optic scanner for determining the size and configuration of the palate, containing a source and a radiation receiver, characterized in that it contains a base in which n-guides are made in the form of depressions with depth h and width b, at intervals ΔX from each other, in which alternately the housing moves, inside of which the optical system is located in the form of incoming and outgoing optical fibers, and the first ends of the optical fibers are parallel to the direction of movement of the housing, and their optical axes are perpendicular to the illuminated surface, and the second ends of the incoming fiber and outlet fiber are connected to the radiation source and radiation receiver, respectively . 4. Fiber-optic scanner according to claim 3, characterized in that the base is flat. 5. Fiber-optic scanner according to claim 3, characterized in that the base is convex. 6. Fiber-optic scanner according to claim 3, characterized in that the base is concave. 7. Fiber-optic scanner according to claim 3, characterized in that the shape of the base follows the shape of the surface on which it is installed. 8. Fiber-optic scanner according to claim 3, characterized in that a microlens is formed at the end of at least one optical fiber. 9. Fiber-optic scanner according to claim 3, characterized in that the first end of the supply optical fiber is located in the vicinity of the focus of the collecting lens.

Images