RU2570289C1 - Method for microbiological estimation of density of connective units of dental implants and dental prostheses - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: preliminary sterilisation of constituent parts of implants is carried out, assembly of connective unit is performed in sterile conditions. Inoculation of microbes in preliminarily sterilised connective units in cavity with through channel for screw in abatment and implant is realised. Sealing of channel is performed by known method. Object under investigation is placed into liquid culture medium, is kept in said culture medium for time, sufficient for microbial growth. If microbial growth takes place, conclusion about permeability of space between implant and abutment for bacteria is made, if microbial growth is absent, conclusion about absence of permeability of space between implant and abutment is made.

EFFECT: method makes it possible to estimate quality of unit connection.

5 dwg

Description

The invention relates to the field of applied medicine, can be used to assess the quality of the connecting nodes of orthopedic dental structures based on intraosseous implants.

For the long-term functioning of dental implant systems interacting with the bone tissue of the jaw and the mucous membrane of the oral cavity, the condition of the connecting nodes arising at the junction “implant-abutment” and “abutment-meso-superstructure”, which form technical interfaces having their own characteristics, is of no small importance. . Among them, the main ones are the gaps between these connecting nodes, and their microbial contamination, which can cause mucositis and peri-implantitis with subsequent complications until the implant is completely lost.

Implant manufacturers and users do not always analyze these factors, relying on the success of hygiene measures. Nevertheless, it is necessary to evaluate the gaps in the implant-abutment and abutment-meso-suprastructure systems. Such an assessment is important both for the production of implants and for the clinic according to the criteria of reliability and effectiveness of the long-term functioning of implant systems and dentures.

It is generally recognized (see the Internet resource http://usasmile.ru/stomatolog/?p=1024 :) that mesostructures and superstructures should be installed passively on the implants so that there are no stresses in the implants and the surrounding bone due to screwing poorly fitted frameworks. Passive overlaying of the implant is considered an important prerequisite for long-term osseointegration.

It is known that for fitting superstructure in the clinic, manual adjustment is used with cutters and burs, but it is impossible to achieve an exact and stress-free fit of the meso- or suprastructure on implants using injection and soldering technology commonly used in dental production.

There are various methods of measuring the gaps between the structural elements of collapsible orthopedic structures based on implants, some of which coincide with the claimed technical solution for the purpose, others according to the presence of matching signs.

The prior art revealed the invention according to the patent of the Russian Federation No. 2126951, the invention relates to measuring equipment, in particular, to devices for measuring the clearance or distance between spaced parts under the name "Probe for measuring the clearance between parts", the essence of which is that the probe contains a case in the form of a glass (1) connected to the main measuring plate in the form of a fork with a handle. A second measuring plate (6) is installed in the fork opening, fixed at one end on a sleeve (8) placed movably in a glass (1). A compression spring (9) is installed in the sleeve with support on the bottom of the glass (1). A longitudinal groove (10) is made in the wall of the glass (1), along which a linear scale of the gaps is applied. In the groove (10), a slider-pointer (12) of the gap value is mounted, fixed in the wall of the sleeve (8). The probe is equipped with a locking slider-pointer (12) in the form of a trigger (13).

The disadvantage of this analogue is that the device is designed to measure gaps between parts in various fields of technology, which makes it very difficult (for a dental surgeon) to bring the measuring probe to the measured area of the implant and the lack of reliability of the results.

The prior art revealed the device according to patent No. 2228157 A DEVICE FOR FIXING A REMOVABLE DENTURE ON IMPLANTS, which is a device for fixing a removable prosthesis containing intraosseous implants and fixing elements, characterized in that it is equipped with elastic plastic bushings, the fixing elements are made in the form of cylindrical metal caps fixed to the base of the removable prosthesis, the prosthesis being fixed to the implants through elastic plastic bushings pre-installed in caps with a gap between the bottom of the cap and the end of the implant.

One of the technical results achieved is the extension of the life of the prosthesis and implants.

The prior art revealed a method of "assessing the accuracy of manufacturing the connecting nodes of dentures based on intraosseous implants" (see Internet pecypc: http://lib.ua-ru.net/diss/cont/405869.html. Where on page 15 Thesis: Mirgazizov Ruslan Marselevich. Evaluation of the accuracy of the manufacture of connecting knots of dentures based on intraosseous implants: the dissertation of the candidate of medical sciences: 14.00.21 / Mirgazizov Ruslan Marselevich; [Place of defense: Federal State Institution "Central Scientific Research Institute of Dentistry"]. - Moscow , 2007. - 104 p.: l.). The essence of the known evaluation method is that, using scanning electron microscopy, gaps were measured at the implant frames fitted manually, as a result of the studies, the method showed that the inaccuracies in the coupling of the mating surfaces were revealed - the gaps varied from 8 to 250 microns, both on the outer edge of the dock, and inside with a longitudinal cut.

A detailed analysis of the images made it possible to see the structure of the gaps, which have uneven pitted porous walls that can cause microbial contamination of the oral cavity and make it difficult to carry out hygiene measures. The disadvantages of the above method is the limited access to expensive equipment (using a scanning electron microscope) and the complexity of the specified studies associated with the involvement of qualified specialists.

The closest by the greatest number of matching signs and the achieved technical result, chosen by the applicant as a prototype, is a method for evaluating the density of compounds based on the principle of exit from gaps of microbes populated inside the implant with known sizes (see Internet resource: http: // science-education .ru / Scientific journal ISSN 2070-7428 "Modern problems of science and education", No 6, 2012 RESEARCH OF TIGHTNESS OF THE DESIGN OF IMPLANT-ABATMENT-SCREW FOR MOUNTING SYSTEMS OF IMPLANTS LIKO, LIKO-M AND NANO-LIKO, Ivanov S.Yu. 1, Solodkaya D.V. 1, Kozlovsky B.C. 1, Solodky V.G. 1, Muraev A.A.).

The essence of the known method lies in the fact that previously sterilized the components of the implants and tools for their assembly (screwdriver) disassembled by autoclaving at 1 atm temperature of 135 ° C for 30 minutes. The implants were assembled in a sterile box with aseptic rules. The abutment opening was sealed with sterile paraffin. Then, each implant in assembled form was placed in a sterile dish and sugar broth with microbial suspension was added. For infection of implants, museum cultures of the American national collection were used: Staphylococcus aureus ATCC 25923 and Bacillus stearothermophilus ATCC 7953. A suspension of the daily culture of microorganisms was prepared in sterile physiological saline according to the GISK standard for turbidity. L.A. Tarasevich, and at a dose of 5 × 103 CFU / ml was mixed with sugar broth in equal volumes. The implants were placed in the resulting mixture for 1, 3, 10, 20 days of incubation at a temperature of 37 ° C, after which the implant was removed with sterile forceps and placed in a sterile container with 6% hydrogen peroxide solution for 30 minutes for decontamination. The implants were rinsed in sterile physiological saline, loosened with a sterile screwdriver and the screw of the abutment was pushed out into a sterile dish with sugar broth using a sterile dental probe, then thermostated 24 hours at 37 ° C. After 24 hours, the sugar broth was sown on blood agar in Petri dishes using a microbiological loop, then the plates were incubated for 24 hours at a temperature of 37 ° C, after which the presence or absence of growth of microorganisms was recorded: in the presence of I growth of microorganisms ascertained a low quality of the compound; otherwise, we ascertained the high quality of the compound. Each experiment was repeated at least three times.

The disadvantages of this method are: the possibility of microbiological infection of the outer surface of the implant during the colonization of microbes and a false idea of their exit from the implant; the method is designed only to determine the density of the implant-abutment connection and is unacceptable for evaluating the gaps between the elements of the orthopedic structure based on the implants.

The purpose of the claimed technical solution is an objective assessment of the density of the connecting nodes “implant-abutment” and “abutment-meso-suprastructure” at the stages of production of implants, as well as at the laboratory and clinical stages of manufacturing orthopedic structures based on intraosseous implants.

The essence of the claimed technical solution consists in a method of microbiological assessment of the density of the connecting nodes of dental implants and dentures, including preliminary sterilization of the components of the implants, the assembly of which is carried out in a sterile box, characterized in that after assembly the microbes are populated into the cavity of the through channel for the screw in the abutment and implant, then perform sealing of the channel, place the test object in a liquid nutrient medium, leave it in the specified nutrient noy medium for a time sufficient for microbial growth; in the presence of microbial growth in the medium, a conclusion is drawn about the insufficient density of the connecting node, in the absence of microbial growth - about a sufficient density.

The claimed technical solution is illustrated by the photographs, on which are presented respectively:

Photo 1 - a sample of an untreated implant with an abutment.

Photo 2 - a sample of a treated implant with an abutment (polished implants).

Photo 3 - polished implants and processed by spark erosion.

Photo 4 - checking the tightness of the connection of the blocks of their 4 implants with the abutment (a block of untreated by the claimed method - spark erosion treatment of implants with superstructure), placed in a container with a nutrient medium.

Photo 5 - checking the tightness of the connection of blocks of 4 implants with an abutment (a block of polished implants with spark erosion processing of the connecting node) placed in a container with a nutrient medium.

The specified goal is achieved by performing the following sequence of operations:

- the assembly of the connecting unit is carried out in sterile conditions on the recommendation of the manufacturer (with a force of 20 N / cm);

- microbes are introduced into sterile connecting nodes between the implant and the abutment, the abutment and the suprastructure;

- sealing of the microbial settlement channel is carried out;

- the preparation and placement of the test object in a liquid nutrient medium is carried out;

- registration of microbial growth in a nutrient medium is carried out within 24 hours of cultivation;

- a conclusion is made about the presence or absence of microbial growth in a nutrient medium, namely: in the presence of microbial growth, a conclusion is made about the permeability of the gap between the implant and the abutment for bacteria (a poor quality of the connecting node has been revealed), in the absence of microbial growth, a conclusion is drawn about the absence of permeability of the gap between implant and abutment (revealed high quality of the connecting node).

The bacteria E. coli K12 were used as a test culture. The choice of bacteria is due to the presence of mobility in the liquid medium in these microorganisms and the ability to grow under anaerobic (microaerophilic) conditions, which are created inside the assembled implant-abutment interface. Also, these bacteria are not spore-forming, and surfaces can be effectively sterilized using 96% ethanol and ultraviolet radiation.

In all cases, 1-2 μl of a liquid culture of bacteria was introduced inside the connective node, in particular, cells of the E. coli K12 strain grown overnight on a nutrient medium — BTN nutrient broth (enzymatic protein hydrolyzate: 10 g, dry enzymatic peptone: 12 g , clarified yeast extract clarified: 2, sodium chloride: 5 g, water 1000 ml) at 37 ° C. The nutrient medium was pre-sterilized in an autoclave at 0.5 atm (110 ° C) for 40 minutes.

Inside a collapsible implant sterilized by autoclaving 0.5 atm (110 ° C), 1-2 μl of a liquid suspension of bacteria (CFU 10 ⁹ ) was injected over 40 minutes. After the assembly of the connector was carried out in sterile conditions on the recommendation of the manufacturer (with a force of 20 N). The technological hole for the connecting screw was filled with BTN-agar melted sterile medium for sealing. Having ascertained the sterility of the outer surface of the implant (having treated the surface with 96% ethyl alcohol), it was placed in the BTN broth nutrient medium so that the medium level exceeded the level of the connecting unit, but was below the level of the technological hole for the connecting screw.

The quality of the implant-abutment compound was judged by the presence of bacterial cell growth, E. coli K12 strain cells, within 2 days after placing the assembled implant in a nutrient medium. For example, the presence of microbial growth after 24 hours in a culture medium in which the infected implant is placed indicates a low microbiological protection of the connective site.

The novelty of the proposed method for assessing the quality of the implant-abutment and abutment-meso-suprastructure interfaces is to use the spark erosion method for passively fitting the suprastructural elements of the implant instead of the traditional fit by a dental technician using metal milling cutters. The application of the method of microbiological assessment can significantly reduce material and time costs, increase the accuracy of fitting supra- and mesostructures on implants, increase the service life of dentures made on intraosseous implants. In addition, visual (and therefore subjective) analysis is replaced by instrumental analysis, free from the subjectivity of a specialist analyst. Consequently, the quality of planning and treatment of dentition defects using dental implants is increased.

results

The tightness analysis of abutment-implant joints with spark erosion treatment began with single collapsible implants. An untreated implant with a superstructure was used as a control (Photo 1), as well as polished implants without spark erosion treatment (Photo 2) and with spark erosion treatment (Photo 3).

The experiments were repeated four times. The experiments showed that in the case of processing the abutment-implant compounds, both with spark erosion treatment and without treatment, in 25 ± 7.2% of cases microbial growth was observed in the medium after 24 hours of cultivation (Photo 4). Therefore, the presence of spark erosion processing of the connecting node did not increase the tightness of the connection. Unexpectedly, the denser junction of untreated implants had greater tightness (8 ± 2.3% of cases of microbial growth at 24 hours of cultivation) (Photo 5). This can probably be explained by the high density of the connection at the interface due to the existing irregularities and roughnesses. However, in real practice conditions this can have a negative effect, since the freedom of spatial orientation of the implant is reduced.

Next, we checked the tightness of the joints in a block of 4 abutments with spark erosion treatment (Photo 5). An untreated block was used as control (Photo 4). Both blocks were installed on the same gypsum model.

As a result of experiments performed in 5 independent repetitions, it was revealed that in a block of 4 abutments connected to a beam without spark erosion, in all cases, after 12 hours, microbial growth was observed, which indicates a low microbiological protection of the connecting node. After 24 hours of cultivation, almost complete overgrowing of the nutrient medium was observed (Photo 4). In the block of abutments connected by a beam with a spark-erosion landing, no growth was found after 24 hours, which indicates a high protection of the connecting node (Photo 5).

The claimed method allows to assess the quality of the interfaces "implant-abutment" and "abutment-meso-suprastructure" of all types and systems of implants. The reliability of the result of the method does not depend on the system of implants and the manufacturer. Therefore, the claimed method for assessing the tightness of the connecting nodes of the implant is universal and free from subjectivity, and the results of the method are more reliable compared to the results of using analogues and prototype, in which the tightness is determined on the basis of visualization of the obtained data and subjective results of expert opinions.

The examples of application of the claimed invention show its usefulness for the quality of the implant-abutment and abutment-meso-suprastructure interfaces, for example, in dental implantology. The application of the claimed method helps to identify deficiencies in the manufacture of dentures on implants, allows you to make timely decisions on improving the quality of the connecting nodes of the superstructural elements.

The claimed technical solution meets the criterion of novelty, since when determining the prior art no means were found that are characterized by features that are identical (that is, coinciding in the function performed by them and the form of these features) to all the features listed in the claims, including the purpose of the application. The claimed technical solution meets the criterion of inventive step, as it is not obvious to specialists in the field of dentistry. The claimed technical solution meets the criterion of industrial applicability, since the claimed method has been tested in the laboratory conditions of the Department of Microbiology, Kazan (Volga Region) Federal University, as a result of which the claimed technical result is obtained.

Claims (1)

A method of microbiological assessment of the density of the connecting nodes of dental implants and dentures, including pre-sterilization of the components of the implants, the assembly of which is carried out in a sterile box, characterized in that after assembly, the microbes are populated into the cavity of the through channel for the screw in the abutment and implant, then the channel is sealed place the test object in a liquid nutrient medium, leave it in the specified nutrient medium for a time sufficient for microbial growth; in the presence of microbial growth in the medium, a conclusion is drawn about the insufficient density of the connective node, in the absence of microbial growth - about a sufficient density.

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