RU2756661C1 - Method for creating intraoral recording apparatus - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to a method for creating an intraoral recording apparatus. Optical impressions are taken from the upper and lower dental arches using the Medit i500 intraoral scanner and stored in the .stl format, then the apparatus is modeled using the Exocad DentalCAD software: in the "Occlusal Splint" module, the hardware basis of the lower jaw is modeled: on the "Border" tab, the borders of the basis are drawn, undercuts are corrected, sharp edges are smoothed, the table of the intraoral apparatus is then formed thereon, serving to record the movements of the lower jaw in three mutually perpendicular planes. Similarly modeled then are the hardware basis and the table of the upper dental arch wherein a hole for the recording stylus is formed. The recording stylus is pre-scanned and loaded into the library of the Exocad DentalCAD program wherein the virtual stylus will be stored thereafter, followed by installing said stylus in a hole on the upper table. A gnathometer is theb printed on a FormLabs Form2 3D printer according to the FormLabs technology from SLA photopolymer resin, cleaned in the Formlabs Form Wash automatic cleaning apparatus, treated in the Formlabs Form Cure ultraviolet curing chamber, and the recording stylus is screwed into the hole in the upper table.

EFFECT: creation of a digital intraoral recording apparatus is achieved.

1 cl, 5 dwg

Description

The invention relates to the field of dentistry, namely to intraoral recording devices (gnatometers), allowing to determine the interalveolar height and the central ratio of the jaws (CSR)

The task of determining the interalveolar height and the central ratio of the jaws (CSR) is key in the clinic of orthopedic dentistry. To solve it, intraoral recording devices (gnatometers) are used.

Closest to the claimed invention is the "Device for determining the ratio of the jaws" (Tsimbalistov AV, Voyatskaya IV Patent for invention of the Russian Federation No. 2093108 from 20.10.1997). The use of a known intraoral recording device makes it possible to record the trajectories of movement of the lower jaw in three mutually perpendicular planes in the form of a "Gothic arc" arrow. The vertex of the intersection of the trajectories (arrows) is the point of definition of the central relation of the jaws. To determine the CSF and interalveolar height, the AOTSO apparatus (apparatus for determining the central ratio) has been developed, which makes it possible to determine the integrated indicator of the maximum compression force of the jaws.

When using the AOTSO device at the first clinical visit, the investigator takes impressions from the upper and lower dentition; then the dental technician creates plaster models of the jaws and individual trays. On the upper individual plastic spoon, a metal support platform is placed in the area of the hard palate, on the lower - a support plate with a force sensor, on which a support pin of the minimum height is installed, corresponding to the distance between the upper and lower jaws in a state of functional rest. Then the force sensor is connected to the recording part of the device, the pins are progressively replaced and the jaw compression force is measured at each pin height. The height of the post at which the maximum force of compression of the jaws was revealed corresponds to the interalveolar height. Then, instead of a pin, a writing rod is fixed to the plate located on the upper jaw and the patient is asked to move the lower jaw (forward - backward, right - to the starting point, left - to the starting point). The top of the resulting Gothic angle corresponds to the CSP point.

The proposed method is difficult to use, there is a high probability of mistakes made by a dentist when using it in practice. Moreover, the AOCO device consists of a large number of component parts (strain gauge, amplifying and measuring unit, battery pack, base plates of three standard sizes, pins from 6 to 23 mm with a height difference of 0.5 mm, pins with a pointed end and a thread in base, sensor simulators), which creates inconvenience in operation.

The objective of the invention is to eliminate these disadvantages by creating a digital intraoral recording device (gnatometer).

The problem is solved by the proposed method of creating an intraoral recording device (gnatometer).

The sequence of its creation is as follows. At the first clinical appointment, a dentist takes optical impressions from the upper and lower dentition using the Medit i500 intraoral scanner (Medit, South Korea). The obtained optical scans are saved in the .stl format and are transferred via Wi-Fi to the dental laboratory.

Further, the dental technician models the hardware bases and tables of the gnatometer using the Exocad DentalCAD software (Germany). The creation of an intraoral recording apparatus is carried out in the "Occlusal splint" module. First, the hardware basis of the lower jaw is modeled: the "Border" tab is opened and, with the help of the computer mouse cursor, the boundaries of the basis are drawn along the points, undercuts are corrected, and sharp edges are smoothed out. Further, on this basis, the table of the intraoral device is formed: the shape and parameters (radius, width, height) of the geometric object that forms the table can be selected in the program library.

Then, in a similar way, the hardware basis and the table of the upper dentition are simulated, in which a hole is formed for the writing pin (its diameter is measured in advance, it is 3.5 mm). Preliminarily, the "physical model" of the writing pin is scanned using a laboratory scanner and loaded into the Exocad DentalCAD program library, after which it is installed in the hole formed on the upper stage. The virtual pen is stored in the Exocad DentalCAD library and is used to create new gnatometers.

Thus, one table is used to record the movement of the lower jaw in three mutually perpendicular planes, the other is used to fix the writing pin in it.

Upon completion of the simulation, the intraoral recording device is printed on a FormLabs Form2 3D printer (FormLabs, USA), operating on the basis of SLA technology (laser stereolithography). The substrate for 3D printing is FormLabs photopolymer resin. After the models are printed, they are cleaned in a special automatic cleaning device Formlabs Form Wash (FormLabs, USA), and then processed in a Formlabs Form Cure UV curing chamber (FormLabs, USA) to ensure uniform curing of the photopolymer resin.

After creating plastic models and hardware bases with tables, the writing pin is screwed into the hole that was previously virtually simulated in the program.

Thus, the gnatometer consists of the following parts (Fig. 1):

1 - model of the lower jaw;

2 - hardware basis of the lower jaw;

3 - table for registration of movements of the lower jaw;

4 - model of the upper jaw;

5 - hardware basis of the upper jaw;

6 - a table with a writing pin of the hardware basis of the upper jaw;

7 - a writing pin with a pointed tip (threaded screw) on the table of the hardware base of the upper jaw.

At the second clinical visit, the investigator places two points on the patient's face - at the base of the nasal septum and on the chin. The patient is involved in a short conversation, at the end of which the lips close freely. The distance between two points (functional height) is measured, after which an intraoral recording device is inserted into the oral cavity of the investigated person. Next, the patient is asked to repeatedly open and close his mouth, controlling the entry of the tip of the pin into one point of the recording table. Then the obtained distance between the marked points on the skin of the face is measured again (morphological height).

The difference in the value of the functional and morphological height in the central ratio of the jaws is, on average, 2-2.5 mm, which corresponds to the normal interalveolar height. If the functional height turns out to be equal to the morphological one, then the interalveolar distance is increased, and, therefore, it is necessary to decrease the screw height by three turns (if the interalveolar height is reduced, the screw height should be increased). One full rotation of the propeller is 360 °. One screw pitch is 0.7 mm. Therefore, in the case of a decrease in the interalveolar height, the screw is rotated counterclockwise by three turns (2.1 mm), obtaining its optimal value. Thus, the interalveolar height is determined.

Next, they begin to determine the CSC. The table on which the movement of the lower jaw was recorded is removed from the oral cavity, its surface is painted over with a marker to obtain trajectories of movement of the lower jaw in three mutually perpendicular planes, after which it is inserted back into the oral cavity.

Then the patient is offered to close his mouth until the writing pin contacts the table and make six movements of the lower jaw from the previously found point, without losing contact of the recording pin with the table:

• forward - backward (sagittal plane);

• to the right - back to the starting point (transversal plane);

• to the left - back to the starting point (transversal plane).

As a result, the table records the movement of the lower jaw in three mutually perpendicular planes, forming the so-called Gothic angle. The position at which the tip of the pin is in the center of the intersection of the three trajectories of movement of the lower jaw is the desired point of the CSF.

The advantages of the proposed method for creating an intraoral recording device using digital technologies are: 1) the absence of errors arising when taking an impression (violation of the rules and proportions of mixing the impression mass, separation of the impression mass from the impression tray when it is removed from the patient's oral cavity, the formation of pores, imprint); 2) fast transfer of the computer file to the dental laboratory via Wi-Fi connection; 3) the precision of modeling the hardware bases and tables of the intraoral recording device; 4) high accuracy of printing models of dentition and intraoral recording device; 5) exact adherence of the base of the intraoral recording device to the dentition (alveolar bone) in the patient's oral cavity; 6) simplicity and speed of creation; 7) the ability to create computer archives for storage and use of computer files in the future.

The invention is illustrated in drawings, where FIG. 1 - Intraoral recording device (gnatometer): 1 - model of the lower jaw; 2 - hardware basis of the lower jaw; 3 - table for registration of movements of the lower jaw; 4 - model of the upper jaw; 5 - hardware basis of the upper jaw; 6 - a table with a writing pin of the hardware basis of the upper jaw; 7 - a writing pin with a pointed tip (threaded screw) on the table of the hardware basis of the upper jaw, Fig. 2 (a-e) Optical impressions of the dentition of patient P .: a - right view; b - front view; c - left side view; d - the occlusal surface of the teeth of the upper jaw; e - the occlusal surface of the teeth of the lower jaw, in Fig. 3 - (a-d) Stages of creating an intraoral recording device using the Exocad DentalCAD software (Germany): a - an optical impression of the dentition loaded into the software; 6 - digital model of the upper dentition with a hardware basis and a table for recording the movements of the lower jaw; c - digital model of the lower dentition with a hardware basis and a table with a writing pin; d - simulated intraoral recording device, FIG. 4 (a-d) - Intraoral recording device in the oral cavity: a - dentition with an installed intraoral recording device; b - the occlusal surface of the upper dentition with an installed hardware basis and a table with a writing pin; c - the occlusal surface of the lower dentition with an installed hardware basis and a table for recording the movements of the lower jaw; d - closed dentition with an intraoral recording device, FIG. 5 (a-c) - Preliminary (temporary) implantation prostheses of the patient P .: a - right side view; b - front view; c - left side view.

The proposed method for creating an intraoral recording device is presented in a clinical example.

Example. Patient P., 63 years old, turned to the clinic of orthopedic dentistry with complaints about the change in the shape of the preliminary implantation prostheses. According to patient P., 3 months after prosthetics with the help of preliminary implantation prostheses on the upper and lower jaws, she began to notice the wear of the artificial teeth.

Objectively. An external examination of the face showed a decrease in the height of the lower part of the face, drooping of the corners of the mouth, the severity of the nasolabial and chin folds. In the oral cavity, there were preliminary implantation prostheses on the upper and lower jaws. Erasure facets were noted on the occlusal surfaces and cutting edges of the artificial teeth of the implantable prostheses (Fig. 2).

Diagnosis. Increased abrasion of artificial tooth crowns.

Treatment. An extended diagnostic plan was drawn up, including: 1) taking optical impressions from the upper and lower dentition (Fig. 2) and modeling an intraoral recording device (Fig. 3); 2) study of the biomechanics of the lower jaw, determination of interalveolar height and CSP using an intraoral recording device (Fig. 4).

FIG. 5 shows new preliminary (temporary) prostheses of patient P., created on the basis of data obtained using an intraoral recording device. The intraoral recording device was manufactured for the patient as described above.

FIG. 1 shows a gnatometer made according to the proposed method, where 1 is a model of the lower jaw; 2 - hardware basis of the lower jaw; 3 - table for registration of movements of the lower jaw; 4 - model of the upper jaw; 5 - hardware basis of the upper jaw; 6 - a table with a writing pin of the hardware basis of the upper jaw; 7 - a writing pin with a pointed tip (threaded screw) on the table of the hardware base of the upper jaw.

The advantages of the proposed method for creating an intraoral recording device using digital technologies are: 1) the absence of errors arising when taking an impression (violation of the rules and proportions of mixing the impression mass, separation of the impression mass from the impression tray when it is removed from the patient's oral cavity, the formation of pores, imprint); 2) fast transfer of the computer file to the dental laboratory via Wi-Fi connection; 3) the precision of modeling the hardware bases and tables of the intraoral recording device; 4) high accuracy of printing models of dentition and intraoral recording device; 5) exact adherence of the base of the intraoral recording device to the dentition (alveolar process) in the patient's oral cavity; 6) simplicity and speed of creation; 7) the ability to create computer archives for storage and use of computer files in the future.

Claims (1)

A method of creating an intraoral recording device - a gnatometer, including taking impressions from the upper and lower dentition; creation of models of jaws, placing a table on them in the area of the hard palate and a table with a pin, characterized in that optical impressions are taken from the upper and lower dentition using the Medit i500 intraoral scanner, the obtained optical scans are saved in the .stl format and via Wi- Fi-connections are transferred to the dental laboratory, then hardware bases and gnatometer tables are modeled using the Exocad DentalCAD software, the creation of an intraoral recording apparatus is carried out in the "Occlusal splint" module: first, the hardware basis of the lower jaw is modeled: open the "Border" tab and using the cursor the computer mouse is drawn along the points of the baseline, the undercuts are corrected, the sharp edges are smoothed, then the table of the intraoral device is formed on this basis: the shape and parameters - the radius, width, height of the geometric object that forms the table, are selected in the program library, then simulated in the same way the hardware basis and the table of the upper dentition, in which a hole for the writing pin is formed, the physical model of the writing pin is previously scanned using a laboratory scanner and loaded into the Exocad DentalCAD program library, after which it is installed in the hole formed on the upper table, and the virtual writing pin is stored in library of the Exocad DentalCAD program, while one table is used to register the recording of the movements of the lower jaw in three mutually perpendicular planes, the other is to fix the writing point in it, after the completion of the simulation, the intraoral recording device is printed on a FormLabs Form2 3D printer operating on the basis of SLA technology -laser stereolithography, moreover, FormLabs photopolymer resin is used as a substrate for 3D printing, after printing the models, they are cleaned in a special Formlabs Form Wash automatic cleaning device, and then processed in the Formlabs Form Cure UV curing chamber. To ensure uniform hardening of the photopolymer resin, after creating plastic models and hardware bases with tables, screw the writing pin into the hole that was previously virtually simulated in the program.

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