RU2279261C1 - Method for determining tooth looseness degree - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: method involves applying variable force to a tooth. Harmonic mechanical oscillations of frequency not exceeding 250 Hz are excited. Mechanical impedance Z is concurrently measured. Lower limit of changes shows extreme tooth looseness degree. The upper limit of changes shows physiologic tooth looseness degree. Mechanical impedance Z value is measured as Nxs/m, where N is the newton, s is the second and m is the meter.

EFFECT: high accuracy and objectiveness of measurements.

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Description

The present invention relates to medicine, namely to dentistry.

Normally, the teeth have physiological mobility, which is necessary for the implementation of trophic function. Evidence of physiological mobility is the presence of polished pads at the contact points between adjacent teeth (V.Yu. Kurlandsky. Orthopedic dentistry. - M .: Medicine, 1969. - P.198).

With a pathological condition of periodontal tissues, the tooth acquires pathological mobility. Thus, the degree of tooth mobility is an indicator of the functional value of periodontal tissues. During remission, pathological mobility may decrease, during exacerbation - increase (Barer G.M. Periodontal disease: clinic, diagnosis and treatment: Textbook. Manual / G.M. Barer, T.N. Lemetskaya. - M .: VUNMTS, 1996 .-- 86 p.). Objectively, to fix this difference today is not possible due to the lack of accurate measuring instruments.

According to some authors, the vertical form of atrophy of the walls of the tooth cavities aggravates the amplitude of tooth mobility (V.I. Kopeikin. Orthopedic treatment of periodontal disease. M .: "Triad - X", 1993. - P.40). However, a clinical examination of periodontitis patients often reveals a mismatch of the same degree of atrophy in the vertical direction and the degree of tooth mobility, it is obvious that not always vertical atrophy of the bone tissue of the tooth cavities has a greater effect on tooth mobility than horizontal.

Tooth mobility can be determined by palpation using tweezers (V.N. Kopeikin. Orthopedic treatment of periodontal diseases. M: "Triad - X", 1993. - P. 41). However, the disadvantage of this method is the subjectivity of the definition.

A known method of determining tooth mobility by applying a variable force to the tooth, providing reciprocating vibrations. The tooth displacement amplitude is measured by isolating two of its components, the magnitude of which judges the elastic and viscous characteristics (see RF Patent No. 2065724, 1996, A 61 B 5/05, A 61 C 19/04).

The closest is a method for determining the state of tooth-retaining tissues using periotestmetry. Periotestmetry is an indirect assessment of the condition of the supporting tissues of the tooth, i.e. periodontal functionality using the Periotest 3218 instrument, calculates the ability of periodontal tissues to return a tooth to its original position after a certain external load (functional or pathological) has been applied to it. The physical principle of the device is to convert an electrical impulse into a mechanical one. The examined tooth is percussed by the striker of the tip directed horizontally and at right angles to the middle of the vestibular anatomical plane of the crown of the supporting tooth, at regular intervals with effort. The results are displayed in the form of an index (see I.Yu. Lebedenko et al. Functional and hardware research methods in orthopedic dentistry. Textbook. - M .: Medical and Information Agency LLC, 2003. - P.97-100).

However, the known methods for determining tooth mobility do not have high measurement accuracy, do not give an objective criterion for the degree of mobility and its quantitative measurement in system units suitable for recording.

The technical result of the proposed method is to increase the accuracy and objectivity of determining tooth mobility by identifying not only pathological but also pre-pathological conditions occurring in periodontal tissues, as well as identifying risk groups among patients.

New in achieving the set technical result is that they excite harmonic mechanical vibrations of the tooth with a frequency of no higher than 250 Hz, at the same time measure the value of the mechanical impedance Z.

гдеAlso new is the fact that the lower limit of changes corresponds to the extreme degree of tooth mobility, and the upper limit corresponds to the physiological tooth mobility. The value of the mechanical impedance is measured in

Where

H is Newton;

s is the second;

m - meter.

и обратно пропорциональной ему величины - подвижности К, измеряемой в единицах

.Harmonic mechanical vibrations of the tooth are excited in the frequency range 1 ... 250 Hz with an amplitude that does not cause pain. At the same time, the amplitude of harmonic oscillations or their vibrational velocity is measured. Both at a constant frequency of harmonic excitation depends on the value of the mechanical impedance Z, measured in units of

and inversely proportional to it - the mobility K, measured in units

.

The authors experimentally discovered and measured the dependence of the degree of tooth tissue pathology and the values of Z and K. The authors determined that at a frequency of 230 Hz the range of impedance changes for teeth with different degrees of pathology is 0 ... 8000. The lower limit corresponds to the extreme degree of tooth mobility preceding loss. The upper limit corresponds to the norm - physiological tooth mobility. The use of a frequency not exceeding 250 Hz is due to the fact that at higher frequencies of vibrational excitation, a deviation from the obtained dependence of the pathology and the measured value is observed. The most convenient for measurements range is 200-230 Hz.

при этом нижний предел изменений соответствует крайней степени подвижности зуба, а верхний предел соответствует физиологической подвижности зуба, что соответствует критерию «новизна».Comparative analysis with the prototype shows that the inventive method differs from the known one in that they excite harmonic mechanical vibrations of the tooth with a frequency of not more than 250 Hz, at the same time measure the value of the mechanical impedance in

the lower limit of changes corresponds to the extreme degree of tooth mobility, and the upper limit corresponds to the physiological tooth mobility, which meets the criterion of "novelty."

A new set of features allows to increase the accuracy and objectivity of determining tooth mobility, which, in turn, allows us to judge the degree of vertical and horizontal destruction of periodontal tissues, to identify risk groups with the aim of carrying out preventive measures in relation to this pathology, which meets the criterion of "industrial applicability".

The method is illustrated in the drawing, which shows a diagram of the use of a device that allows measurements in the oral cavity, where 1 is a tooth, 2 is a contact tip, 3 is a receiving piezoelectric element, 4 is a sound duct, 5 is an emitting piezoelectric element.

The method is as follows.

Нижний предел соответствует крайней степени подвижности зуба, предшествующей выпадению. Верхний предел соответствует физиологической подвижности зуба.To measure tooth mobility 1, a combined rod-type sensor is used, consisting of a contact tip 2, a receiving piezoelectric element 3, a sound pipe 4, a radiating piezoelectric element 5. An alternating sinusoidal voltage of a given frequency is supplied to the radiating piezoelectric element from a low-frequency oscillation generator. The receiving piezoelectric element is connected to a selective voltmeter tuned to the frequency used. The voltage at the receiver element of the sensor is proportional to the mechanical impedance. The sensor is installed horizontally and at right angles to the middle of the vestibular surface of the coronal part of the studied tooth. The dentition of the patient is open. Harmonic mechanical vibrations of the tooth with a frequency of not more than 250 Hz, for example, in the range of 200-230 Hz with an amplitude that does not cause pain, are excited longitudinal or transverse relative to the axis of the tooth. Determine the measured voltage on the scale of the device. The voltmeter scale is graded in units for impedance Z. The range of impedance changes for teeth with varying degrees of pathology is 0 ... 8000

The lower limit corresponds to the extreme degree of tooth mobility preceding loss. The upper limit corresponds to the physiological mobility of the tooth.

The proposed method for determining tooth mobility is illustrated by the following clinical examples.

Example 1. Patient Fedotova MV, 27 years old, went to the dental clinic to the dentist about the phenomenon of hyperesthesia of the teeth.

Inspection Extraoral: the face is symmetrical, the height of the lower third of the face is normal, nasolabial and chin folds are moderate. The mouth opens 4 cm. When opening the mouth, deviation of the lower jaw is noted. The state of physiological rest is 1.5 mm. On palpation, the masticatory muscles are dense, painless. Intraoral: the mucous membrane of the vestibule of the oral cavity is pale pink, without pathological changes, wet, gingival pockets are not detected, there is no visible gum retraction, tooth mobility with tweezers is not observed. The oral hygiene index of Yu.A. Fedorov - V.V. Volodkina is good. The Schiller-Pisarev test is negative. The PMA index is 0. Bite: orthognathic. To determine the mobility of the teeth using our device, the sensor was installed horizontally and at right angles to the middle of the vestibular surface of the coronal part of the tooth under study. Harmonic mechanical vibrations with a frequency of 230 Hz were excited with the simultaneous measurement of mechanical impedance, which in the area of the teeth of the lower and upper jaw is equal to the average limit, which corresponds to an average degree of mobility.

Dental formula:

pppu p u ppp 87654321 12345678 7654321 1234567 ppp ppp

On the orthopantomogram performed in the central occlusion position, the heads of the lower jaw on the right and left are located at the base of the slope of the articular tubercle. There is a uniform horizontal atrophy of the bone tissue of the alveolar process in the area of the dentition of the upper and lower jaw 1/3 of the length of the roots of the teeth. The nasal septum is not curved, the maxillary sinuses are radiopaque.

Diagnosis: Partial absence of teeth in the upper jaw. Bruxism, complicated by generalized moderate periodontitis, stage of remission. Muscular - articular dysfunction of TMJ.

Example 2. Patient Shelomentsev EV, 18 years old, went to the dental clinic to the dentist for a routine examination.

Extraoral: the face is symmetrical, the height of the lower third of the face is normal, the nasolabial and chin fold are moderate. The mouth opens at 4 cm, the movements of the lower jaw are smooth, the state of physiological rest is normal.

Intraoral: the mucous membrane of the vestibule of the oral cavity is pale pink, without pathological changes, moist, periodontal pockets absent. The oral hygiene index of Yu.A. Fedorov - V.V. Volodkina is good. The Schiller-Pisarev test is negative. The PMA index is 0. The tooth mobility of the proposed method corresponds to the upper limit. Orthognathic bite. Dental formula:

P 87654321 12345678 87654321 12345678 P

On the orthopantomogram performed in the usual position of occlusion, the heads of the lower jaw are located at the base of the slope of the articular tubercle. The cortical locking plate is preserved throughout. The nasal septum is not curved, the maxillary sinuses are radiopaque.

Diagnosis: healthy.

Claims (1)

A method for determining tooth mobility by applying a variable force to a tooth, characterized in that they produce harmonic mechanical vibrations with a frequency of no higher than 250 Hz, simultaneously measure the value of mechanical impedance Z, while the lower limit of changes corresponds to the extreme degree of tooth mobility, and the upper limit corresponds to physiological mobility tooth, and the value of the mechanical impedance Z is measured in

, where H is Newton; s is the second; m - meter.