BG4238U1 - Universal gnathodynamometric (strain gauge) system - Google Patents

Abstract

The utility model represents a universal gnathodynamometric (strain gauge) system that allows automated measurement of maximum bite force (MBF) in real time and in four measurement modes: linear measurement, peak value memorizing, peak memory reset, sensor reset in the absence of signal. The universal gnathodynamometric (strain gauge) system according to the utility model operates under the control of dedicated software and is powered by a lithium rechargeable battery which is automatically charged by an external charger.

Description

Field of technique

The system according to the useful model finds application in the field of dentistry and specifically, in gnathodynamometry.

Prior art

Gnathodynamometry is a dynamic method for establishing the effectiveness of chewing function, widespread in dentistry and in particular in prosthetic dentistry. In fact, it is a method to establish the quantitative characteristic of masticatory function. Through it, the quantitative value of the periodontal resistance of the teeth is established, i.e. and the very strength of the periodontium. As characterizing the functional state of the masticatory apparatus, the term Maximum Bite Force (MBF) has been established. By measuring with a gnathodynamometer, it was concluded that MBF is higher in men and is different in individual parts of the dentition. It is also established that it depends on the interocclusal (interdental) distance, being the highest when it is 20 mm. When comparing the values obtained in natural dentition, in the presence of a crown or bridge made of a certain material, when using a certain type of removable prosthesis, with the help of gnathodynamometry, a maximally accurate and objective assessment of the various types of prosthetic structures can be made.

Currently, the so-called one-dimensional gnathodynamometry. With her, the MSZ is measured only during vertical movement of the lower jaw. The first gnatho-dynamometric studies were performed in completely natural dentition to establish the normal endurance limits of the periodontium. The principle consists in placing the device between the upper and lower jaw and asking the patient to squeeze until the first appearance of pain. Based on these studies, tables were created for the durability and functional suitability of each individual tooth. When summing the values from each tooth, the so-called chewing coefficient of the entire dentition is formed, or in other words, the patient's ability to process food mechanically.

To date, no less than 30 different types of gnathodynamometers have been developed around the world. In general, these are devices created on the principle of force-measuring devices. Most devices used in practice are complex mechanical structures, difficult to manipulate and uncomfortable for patients. A similar device is described in the work [The effect of denture adhesive on bite force until denture dislodgement using a gnathometer Guang Hong, DDS, PhD,a Takeshi Maeda, DDS, PhD,b and Taizo Hamada, DDS, PhDa aDepartment of Oral Health Care Promotion , Graduate School of Dentistry, Tohoku University, Sendai, and bDepartment of Advanced Prosthodontics, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan (Int Chin J Dent 2010; 10: 41-45)].

Technical nature of the utility model

The system according to the utility model is fully electronic, controlled by a microcontroller and uses a strain gauge sensor to measure the Maximum Bite Force (MBF) with high accuracy. Working with it is simplified, the measurement is performed in real time and the procedure does not cause inconvenience to the patient. It can find universal application in gnathodynamometry.

Principle of operation of the universal gnathodynamometric (tensometric) system, according to the useful model (Fig. 1)

The principle of operation of the universal gnathodynamometric (tensometric) system, according to the useful model, is based on the application of a tensometric force meter and microprocessor control of the received information. Bite force is applied to the force meter. The electrical signal is amplified in an electronic unit and processed by the microprocessor system according to the control software. The resulting MBF value result is visualized.

The application of the measured force P on the contact points of the sensor block causes bending of the elastic element of the sensor block 11. This leads to the occurrence of a deformation state in the area of the applied tensor resistors from the strain gauge bridge 12. The bridge circuit, which is powered by a block of a reference source voltage 5 from an electronic block and is pre-balanced at zero value of the force P, is unbalanced. An electric voltage occurs in the measuring diagonal of the bridge in proportion to the measured force P. The signal is transferred along the cable to the input of the input analog signal amplifier block 1, amplified and fed to the analog-to-digital converter (ADC) built into the control microcontroller 4. The microcontroller processes the received digital information in accordance with the commands of the specialized software with which it is programmed and according to the current status of the keyboard 3. The received information is displayed in digital form by a block of digital four-digit indication 2, directly in dimension Newtons (N). The entire electronic circuit and the sensor are powered by a rechargeable lithium battery 7, by means of a voltage converter 6, which ensures the constancy of the supply voltage, regardless of the battery voltage drop over time. The battery is recharged by a specialized charging unit 8, which works in semi-automatic mode with its own control. The unit provides automatic shutdown of the battery upon reaching an upper critical charging threshold. The energy required to charge the battery is provided by the mains 220 V 50 Hz by means of the mains charging unit adapter 9.

Essentially, the universal gnathodynamometric (tensometric) system, according to the utility model, is built from a sensor block 11, which is simultaneously in connection with a reference voltage source block 5 and a block of input analog signal amplifier 1, which block of input analog amplifier of the signal 1 is connected to a microcontroller 4, provided with a built-in analog-to-digital converter, connected to a block of digital four-digit indication 2 and a control keyboard 3, and a rechargeable lithium battery 7 is provided for power supply, which through a voltage converter 6 is connected at the same time with the microcontroller 4, the control keyboard 3 and the reference voltage source block 5. The sensor block 11 is preferably made up of a connected strain gauge sensor that converts the bite force into an electrical signal and a strain gauge bridge 12, and the control keyboard 3 in one embodiment is selectable for different measurement modes. Preferably, moreover, the microcontroller 4, with a built-in analog-to-digital converter, is in connection with a block of specialized control software.

Explanation of the attached figures

Figure 1 is a schematic block representation of the universal gnathodynamometric (tensometric) system, according to the utility model;

figure 2 - sensor block of the universal gnathodynamometric (tensometric) system, according to the utility model;

figure 3 - electronic block of the universal gnathodynamometric (tensometric) system, according to the useful model;

figure 4 - network charging block of the universal gnathodynamometric (tensometric) system, according to the utility model.

An example of a specific implementation of the universal gnathodynamometric (tensometric) system, according to the useful model (see fig. 1, 2, 3, 4)

The universal gnatho-dynamometric (tensometric) system, according to the utility model, in one embodiment is an electronic system for processing information obtained from a strain-metric force-measuring sensor. The process is controlled by a microcontroller under the control of specialized software. The structural diagram of the universal gnathodynamometric (tensometric) system according to the useful model is shown in Fig. 1. Blocks are marked as follows:

• a block of input analog amplifier of the signal from the measuring diagonal of a tensometric bridge 12, applied on a block of sensor 11;

• block of digital four-digit indication, providing max. reading "1023". Controlled by microcontroller 4.

• Keyboard. It is located on the front panel of the device, location and functions of the control buttons: ON, Mem ON/OFF, Reset Mem Reset.

Button 1 "Mem ON/OFF" - Function: Turn on/off peak memory. When the device is initially turned on (by means of the Main electrical switch 10) the peak memory function ("Mem ON") is automatically activated, which is indicated by the "ON" LED and the device goes into the "maximum value measurement" mode. The peak memory function triggers the procedure of saving the display of the last maximum value that was applied to the sensor block 11. In this mode, expecting a higher value than the already stored value, the device can remain for an unlimited time. When the button is pressed again, the peak memory function is exited ("Mem OFF"), the "ON" LED goes out, the display shows the current measured value and the device switches to the "linear measurement" mode.

Button 2 “Mem Reset” - Function: Reset peak memory. In the peak memory function mode ("Mem ON"), the last current maximum value is deleted by the "Mem Reset" function and the continuation of the measurement is allowed.

Button 3 "Reset" - Function: Reset the current reading in the "linear measurement" mode ("Mem OFF").

The starting point of the reading is accepted again - until the next actuation of the button.

• Microcontroller with built-in analog-to-digital converter (ADC). It works under the management of specialized software.

• Reference voltage source block for the supply diagonal of strain gauge bridge 12, applied to the elastic element of sensor block 11.

• Voltage converter (DC-DC converter) and regulator. It supplies power to all units of the unit and in turn receives power from a rechargeable lithium battery 7.

• Rechargeable lithium battery. It is connected to the circuit via the main electrical switch 10 ("Power ON/OFF"). Subcharging is provided by charging unit 8.

• Charged unit. Provides the necessary charge procedure for a rechargeable lithium battery 7, with appropriate protections. An LED registers the start and end of the process.

• Mains charging unit. Provides supply voltage for charging unit 8. Connects to a 220 V network. The presence of supply voltage for charging unit is indicated by an LED.

• Main electrical switch ("Power ON"). Turns on and off the battery 7 to the circuit diagram of the unit.

• Sensor block. It is an independent structural unit composed of an elastic element and auxiliary elements. The elastic element converts the applied force P into deformation of the applied tensor resistors making up the tensometric bridge 12.

• Tensometric bridge. It consists of four tensor resistors included in a Wheatstone bridge circuit. The deformation of the tensor resistors applied to the elastic element is converted into a voltage, which is fed to the input analog signal amplifier block 1.

• Sound alarm. Indicates that the measurement range has been exceeded by a periodic sound signal. It is operated by microcontroller 4.

Constructive implementation of the universal gnathodynamometric (tensometric) system, according to the useful model

The universal gnathodynamometric (tensometric) system, according to the useful model, is formed as three interconnected blocks: a sensor block, an electronic block and a mains charging block.

Thus, in an exemplary embodiment, the universal gnatho-dynamometric (tensometric) system, according to the utility model, is constructed from a sensor block 11, which is simultaneously connected to a reference voltage source block 5 and an analog input signal amplifier block 1, which block of an input analog signal amplifier 1 is connected to a microcontroller 4, provided with a built-in analog-to-digital converter, connected to a block of digital four-digit indication 2 and a control keyboard 3, and a rechargeable lithium battery 7 is provided for power supply, which through a voltage converter 6 is in communication simultaneously with the microcontroller 4, the control keyboard 3 and the unit of reference voltage source 5. The sensor unit 11 preferably consists of a connected strain gauge sensor that converts the bite force into an electrical signal and a strain gauge bridge 12, and the control 3 in this implementation is filled with the possibility of choosing the different modes of measurement. In addition, the microcontroller 4, with a built-in analog-to-digital converter, is here in connection with a block of specialized control software.

Sensor block (Fig. 2 and also Fig. 1).

The unit is designed as a unitary assembled unit, with a convenient handle for handling by the tester and a 2250 mm long cable for connection to an electronic unit. Its overall dimensions are 195 x 0 40 mm. The measuring tip, with overall dimensions of 25 x 12 x 9 mm, is equipped with contact buds mounted in the holes 03. They ensure that the application of the measured force P is always at the same point, which determines the repeatability of the readings. The measuring tip is an extension of the elastic element, mounted to the handle of the sensor block and protected externally by a stainless steel housing. Four tensor resistors connected in a bridge circuit are applied to the elastic element. The signal is output via a cable with a diameter of 0.5 mm and a length of 2250 mm. On the handle side, the cable is fixed and sealed by means of a gland, and at the opposite end it is connected to the plug of a connector 52 mm long, for connection to the socket of the connector mounted in the housing of the electronic unit.

Specifications: Degree of protection - IP56 Cable length (including connector) m 2.3 Weight (including cable and connector) g 650 Construction materials - stainless steel and polymer Measuring range N 0 ... 500 Additional overload % 150

Electronic block (see Fig. 3 and Fig. 1)

The unit is enclosed in a unitary polymer housing with overall dimensions of 950 x 63 x 28 mm. The front panel is located on the top cover, where the keyboard buttons, the "ON" signal LED and the LED indication are located. On the front side panel are the main power switch ("Power ON/OFF"), the connector socket for connection to the sensor unit, the input socket for the power adapter jack of the mains charging unit (size 0 3 mm) and the CHARGE LED , indicating the charge process. The four screws for removing the cover are located on the bottom cover. The housing houses the printed circuit board on which all the electronic components and the battery are mounted.

Specifications: Weight without cables kg 0.140 Degree of protection - IP42 Construction material - polymer Dimensions mm 95 x 63 x 28

Mains charging unit (see Fig. 4 and Fig. 1)

The block is formed in a unitary housing with overall dimensions of 95 x 74 x 53 mm, the lower part of which is a standard 220 V Shuko socket. The control LED registering the presence of supply voltage and a 0.2 A fuse socket are located in the upper part. The output cable with length 2300 mm, ends with a jack 0 3.5 mm for connection with a charging unit. An AC-DC voltage converter from 220 VAC to 5VDC is located in the housing, containing a transformer, a rectifier, a voltage regulator and an output for a control diode. There are three screws for disassembly on the bottom cover.

Technical data: Degree of protection - IP42 Dimensions mm 95 x 74 x 53 Zahr. tension VAC 220 Cable length (including jack) m 1.64 Weight kg 0.300

Full technical characteristics of the universal gnathodynamometric (tensometric) system, according to the utility model:

Accuracy class - 0.2 Number of entries strain gauge. channels - 1 Measurement ranges section 0 ... 1023 Number of data indicator digits - 4 A-D conversion bit rate bits 10 (1024 divisions) Conversion factor N/part 1/1 Temp. coefficient of the null signal %/10 ^o C 0.02 Temp. amplification factor %/10 ^o C 0.02 Operating temperature range ^about S 0 . 40 Zahr. tension VDC 2.7. 4.2 Power consumed W 0.25 (max.) Software variant - DCU Measuring range N 0 . 500 Additional overload % 150 Relative non-linearity error % < 0.2 Output voltage from charger VDC 5

Power consumed by charger W

Claims (1)

Universal gnatodynamometric (strain gauge) system, characterized in that it consists of a sensor unit (11), which is simultaneously connected to a reference voltage source unit (5) and an analog input signal amplifier unit (1), which block of input analog signal amplifier (1) is connected to a microcontroller (4), provided with a built-in analog-to-digital converter connected to a block of digital four-digit indication (2) and control keypad (3), and power supply is provided rechargeable lithium battery (7), which through a voltage converter (6) is connected simultaneously with the microcontroller (4), the control keypad (3) and the reference voltage source unit (5)