RU2848402C1 - Method for direct restoration of masticatory teeth using a system of occlusal counter-dies - Google Patents

Abstract

FIELD: medical science.

SUBSTANCE: invention refers to medicine, namely to dentistry, and can be used in direct composite restoration of an occlusal surface of masticatory teeth. Direct restoration of the masticatory teeth is ensured by a system of occlusal counter-dies. For making the occlusal counter-dies of the masticatory teeth, average parameters of the occlusal surfaces of the masticatory teeth of the upper and lower jaws are calculated by measuring the occlusal surfaces in the mesiodistal and vestibulo-oral directions and determining the height of the cusps. Derived values are used to make a set of masticatory teeth counter-dies of two size series taking into account individual characteristics. After preparation of the formed carious cavity for filling, a required size of the counter-die of the respective tooth is selected from a set of occlusal counter-dies of the appropriate size range, and the counter-die is fitted. After verifying the required stamp, the enamel and dentin are prepared by etching the enamel and dentin with 37 % orthophosphoric acid gel for 30 and 15 s, and after the dentin is sealed with a fluid composite and the dentin floor is restored, the final portion of the packed enamel composite is applied. Then the surface of the non-polymerised composite is covered with a polytetrafluoroethylene membrane, and the composite is pressed out with a counter-die to build cusps of the occlusal tooth surface. First polymerization is performed through a transparent counter-die; then the stamp with the membrane is removed, and polymerization is repeated for 1 minute, providing thereby a high-precision reproduction of the cusps of the masticatory surface of the tooth.

EFFECT: by using the system of occlusal counter-dies, the method enables providing higher effectiveness, quality and rate of carious cavity filling of masticatory teeth, as well as creating an aesthetic and functional restoration taking into account the patient’s age characteristics.

1 cl, 5 dwg, 3 tbl, 1 ex

Description

The invention relates to medicine, namely dentistry, and can be used to increase the efficiency of performing direct composite restoration when restoring the occlusal surface of the chewing group of teeth during the treatment of extensive carious cavities.

In recent decades, progress in dentistry has led to the introduction of new technologies and materials for the digitalization of treatment (Lebedenko I.Yu., 2020; Krikheli N.I., 2023; Watanabe N., 2022). Currently, various methods for restoring the occlusal surface of chewing teeth are used: direct/indirect composite restoration, the use of silicone templates, etc. (Tsalikova N.A., Mitronin V.A., 2021). Despite the increasingly widespread use of ceramic restorations in modern dentistry, the direct composite restoration method in most cases is the most optimal treatment option, which allows for an effective solution to the problem of minimally invasive restoration of defects in hard dental tissues (Mitronin A.V., Ostanina D.A., 2022). The advent of hybrid composite materials in dentistry has contributed to the popularization of minimally invasive treatment approaches for even extensive carious lesions (Mitronin A.V., Ostanina D.A., Abiev E.Ch., 2021). Modern dental standards focus on the high aesthetic, structural, and functional properties of composite restorations for various tooth groups. This is essential for improving patients' dental and overall health, which ultimately improves their quality of life (Kodzaeva Z.S., Turkina A.Yu., 2019).

However, when performing direct composite restorations, modeling the anatomical characteristics of teeth has its own specific challenges, requiring high manual skills, in-depth knowledge of anatomy, and high speed of fabrication (Flavio F., Britto C., 2023). Given the above, the development and implementation of digital methods for the reconstruction of hard dental tissues in practical healthcare seems relevant.

A method for restoring the occlusal surface of teeth is known [Patent 2502494 Russian Federation, IPC A61C 13/097. Method for restoring the occlusal surface of teeth / S.D. Arutyunov, O.O. Yanushevich, M.M. Antonik, [et al.] applicant and patent holder S.D. Arutyunov - No. 2012152674/14; declared 12.07.2012; published 12.27.2013, Bulletin No. 36. - 5 p.], according to which a template milled from transparent ash-free plastic is used to restore teeth. The template is then cut in half and used as a press mold in the manufacture of restorations using composite material, which is then polymerized with a lamp through the transparent surface. This method is complex to implement and also requires work with a dental laboratory, specifically the production of plaster models, their fixation in an articulator using a face bow and axiographic data, as well as the formation of templates from ash-free plastic, which significantly increases the time for restoring the occlusal surface of the tooth and increases labor and financial costs.

A method for restoring the occlusal surfaces of the chewing group of teeth is known [Patent 2402994 Russian Federation, IPC A61C 13/00 (2006.01), A61C 19/00 (2006.01). Method for restoring the occlusal surfaces of the chewing group of teeth / S.D. Arutyunov, I.M. Makeeva, E.K. Makeeva, [et al.] applicant and patent holder FSBEI HE "Moscow State University of Medicine and Dentistry of the Federal Agency for Healthcare and Social Development of the Russian Federation" - No. 2009107784/14; declared 05.03.2009; published 10.11.2010, Bulletin No. 31. [- 5 sec.], which involves fabricating a mouthguard from a celluloid plate, pressed in a vacuum apparatus, using the T-Scan automated bite analysis system. Composite material is then added to the mouthguard, bonded to the teeth, and polymerized. A disadvantage of this method is that the restoration of hard dental tissue defects is performed using wax modeling, the use of an automated bite analysis system, and the T-Scan apparatus, which complicates the crown restoration procedure, increases the time required, and requires expensive equipment.

A method for modeling the occlusal surface of a tooth is also known [Patent 2749689 Russian Federation IPC A61C 13/097 (2006.01) G09B 23/28 (2006.01). Method for modeling the occlusal surface of a tooth / E.N. Sharafutdinova, applicant and patent holder E.N. Sharafutdinova - No. 2020139366; declared 01.12.2020; published 16.06.2021, Bulletin No. 17. - 5 p.], which includes creating an occlusal stamp by applying a flowable material to the tooth. An occlusal stamp is made from a corrective silicone mass, which is obtained by mixing the activator and corrective silicone mass until homogeneous. It is applied to the occlusal, vestibular, lingual, and approximal tooth surfaces in a layer at least 4 mm thick. Next, the occlusal impression is removed from the tooth surface, the carious defect is prepared, the defect is filled, and the formed silicone occlusal stamp is applied to the last portion of the light-cured filling material, and the composite material is polymerized. A disadvantage of this restoration method is that performing a composite restoration using this template requires the preservation of the anatomy of the occlusal surface of the tooth, which is extremely rare. Moreover, in the presence of an extensive hard tissue defect, this restoration method is impossible.

The prototype of the invention is a device for forming the chewing surface of a tooth [Patent 209087 Russian Federation, SPK A61C 5/62 (2022.01), A61C 13/097 (2022.01.). Device for forming the chewing surface of a tooth / N.V. Adaeva, applicant and patent holder N.V. Adaeva - No. 2021127746; declared 09.22.2021; published 02.01.2022, Bulletin No. 4. - 6 p.], which is a stamp made of cobalt-chromium alloy containing a surface corresponding to the chewing surface of the tooth and used for its modeling. The carious cavity is prepared, the tooth cavity is formed, etched, an adhesive system is applied using an applicator, and the cavity is filled with a plastic filling material. Next, a device is selected to shape the tooth surface with a stamp, the surface of which corresponds to the anatomical shape of the tooth being filled, using the markings on the handle as a guide. The filling material is deformed by briefly pressing the stamp surface against it. The stamp is then removed, and the formed chewing surface is polymerized by curing with a lamp. A disadvantage of this device is the lack of a statistically derived size range of stamp occlusal surfaces for all chewing teeth, limiting its versatility in restoring the chewing surface of teeth during caries treatment. Another drawback is the stamp material, which increases the weight of the device, making it inconvenient to use.

Based on this, it should be concluded that it is necessary to develop the most advanced methods for filling carious cavities of any extent using modern materials and 3D technologies.

The objective of the claimed invention is to develop a universal system of occlusal counter-dies for direct restoration of posterior teeth. The universal filling system includes counter-dies of different sizes for each posterior tooth of the upper and lower jaw, which represent a reverse reflection of the occlusal surface of an intact tooth. The authors propose a method characterized by simplicity, low time consumption, and high efficiency.

The technical result of the claimed invention consists in increasing the efficiency, quality, and speed of filling carious cavities in the chewing group of teeth through the use of the developed universal system of occlusal counter-stamps, which allows for the creation of a functional restoration taking into account the age characteristics of patients and constructing a physiological tubercular compass on the restored occlusal surface of the teeth using modern 3D modeling and printing technologies.

The technical result is achieved as follows. During caries treatment, after necrectomy and finishing of the cavity margins, the cavity is filled using composite materials. During the preparatory stage, the appropriate counterstamp size for the corresponding tooth is selected from a universal set of occlusal counterstamps (Fig. 1) and fitted. After verifying the correct counterstamp size, the cavity is prepared by etching the enamel and dentin with 37% orthophosphoric acid gel for 30 and 15 seconds, respectively. Adhesive preparation of the cavity is then performed using an adhesive system in accordance with the manufacturer's instructions. Filling of the cavity begins by sealing the dentin with a flowable composite material. A portion of the filled composite material matching the dentin shade is then inserted into the cavity, which is packed and adapted. The enamel floor of the cavity is then restored using a portion of packable composite in the same shade as the enamel. The material is applied to the cavity margins using an applicator. A tetrafluoroethylene (PTFE) polymer membrane is then applied to the surface of the unpolymerized composite, and the composite is pressed onto it with a counterstamp to build up the cusps of the occlusal surface of the tooth. The initial polymerization is performed through a transparent counterstamp, then the stamp and membrane are removed, and a second polymerization is performed for 1 minute. Excess composite is removed using coarse polishers, fine abrasive burs, or carbide burs, and the restoration is then polished.

To validate our findings and the proposed universal occlusal counter-die system, during the first stage of development, the average statistical parameters of chewing teeth were calculated for standardizing the size range. Specifically, the first and second premolars and first and second molars on the contralateral sides of the upper and lower jaws were calculated. To calculate these parameters, the occlusal surfaces of the upper and lower chewing teeth in 350 patients were examined using a Trios intraoral scanner (3SHAPE A/S, Denmark) and Geomagic Control X 3D modeling software, taking into account three parameters: mesiodistal and vestibulo-oral dimensions and cusp height. To find the size of the chewing surface of the teeth in the mesiodistal direction, the distance passing through the midpoints on the approximal surfaces of each tooth was measured, in the vestibular-oral direction - the distance passing through the midpoints on the vestibular and oral surfaces, the height of the cusps was measured using the method described in patent No. 2438617 [Patent 2438617 Russian Federation IPC A61C 5/00 (2006.01). Method for measuring the sizes of teeth, dental cusps and their internal and external slopes / I.K. Batrak, G.V. Bolshakov, A.V. Gabuchyan; applicant and patent holder I.K. Batrak, G.V. Bolshakov, A.V. Gabuchyan - No. 2010135835; declared 14, 30.08.2010; publ. [January 10, 2012, Bulletin No. 1. - 12 p.]. A statistical analysis of the data was performed using variation statistics methods. The study revealed that tooth sizes can be reduced to certain average parameters. Therefore, based on the determined values of the average statistical dimensions of the occlusal surface of the chewing group of teeth, two sizes (small and large) of counter-dies were selected for each tooth, taking into account their individual characteristics (Table 1).

Computer technologies were used to develop counter-stamps, namely the PlastyCAD 3D modeling program, in which counter-stamps were modeled for all occlusal surfaces of the chewing teeth of the upper and lower jaws on the contralateral sides in two sizes according to the statistical data obtained in the first stage of the study.

In the second stage of the study, when selecting the material from which the counter-stamps would subsequently be made, two prototype samples were produced for subsequent testing using a Formlabs Form 3 3D printer from UV-transmitting and UV-blocking plastics Harz labs clear and Harz labs Yellow, respectively.

Harz labs plastics (photopolymers) are high-precision and hard materials for 3D printing, possessing high tensile strength and resistance to mechanical stress (S. Clark, R. Liska, 2021).

To determine the polymerization of the composite using a counter-die, the international method ISO 4049 "Depth of polymerization of composite materials" was used. In accordance with this method, the composite materials under study (Estelite Quick A1 "Tokuyama Dental", Harmonize Enamel A1 "Kerr", Charisma classic A1 "Kulzer") were placed in metal molds (n=9) made of stainless steel with a length of 6 mm and an internal diameter of 4 mm and covered with PTFE tape. The materials were divided into 3 groups according to the material of the counter-die (n=9):

Group 1 - using a counter stamp made of ultraviolet-resistant plastic Harz labs Yellow (n=3);

Group 2 - using a counter stamp made of ultraviolet-transmitting plastic Harz labs clear (n=3);

Group 3 – control group – without using a counter stamp (n=3).

Each sample was then cured for 40 seconds using a Woodpecker LED B lamp (Woodpecker, China). After opening the metal mold, excess uncured material was removed with a trowel. The length of the cured material was then measured using an Inforce 0-25 mm electronic micrometer. The results are presented in Table 2.

According to the results of the study, the Harz Labs Clear photopolymer is the material of choice for counterstamp production. However, after initial polymerization of the composite material through the counterstamp, it is recommended to perform final polymerization of the composite for 1 minute after removing the counterstamp.

To evaluate the effectiveness of the proposed technology, 40 upper jaw molars were divided into 2 groups according to the filling method:

Group 1 – use of the direct composite restoration method (n=20);

Group 2 – application of the direct composite restoration method using a counter-stamp (n=20).

During the study, Estelite Quick Al (Tokuyama Dental) composite material was used for filling teeth in both experimental groups. Marginal adhesion was assessed using scanning electron microscopy, while filling speed was measured using a stopwatch. The data were statistically analyzed using SPSS 22.

The study results showed no statistically significant differences between the study groups in terms of the quality of marginal seal of the filling (p<0.132). However, the average speed of direct restoration in the two experimental groups differed (Table 3).

The study found that an optimized direct composite restoration method using a counter-stamp system accelerates the treatment process by 2 times, without reducing the quality of the marginal seal of the filling, compared to the traditional filling method.

Thus, with traditional methods of filling a carious cavity, the dentist relies solely on their knowledge and skills to reproduce the intercuspal compass when reconstructing a severely damaged tooth. This often doesn't correspond to the physiological characteristics of the teeth being restored and negatively impacts the intercuspal relationship with the opposing teeth. This subsequently leads to rapid wear of the restoration, chipped fillings, traumatic occlusion, and/or dysfunction of the temporomandibular joint. Furthermore, dentistry today strives to improve the aesthetics of treatment, so dentists spend more time aesthetically restoring the natural anatomy of the chewing surface of teeth, which is often extremely difficult to reproduce. At the same time, the use of a universal counter-die system allows dentists to perform direct composite restorations quickly, precisely, and in accordance with the natural anatomy and function of the teeth, which is a key factor in optimal caries treatment. Therefore, the use of a universal occlusal counter-die system represents a promising method for filling carious lesions during therapeutic oral hygiene, improving the quality of dental treatment for patients and promoting oral health.

List of figures.

Fig. 1 System of universal occlusal counter-stamps (large size.

Fig. 2. Clinical photograph of tooth 1.6 before treatment.

Fig. 3. Clinical photograph of tooth 1.6 after necrectomy and finishing of enamel edges.

Fig. 4. Selection and fitting of a counter-die for tooth 1.6 (large size) from the system of universal occlusal dies.

Fig. 5. Clinical photograph of tooth 1.6 after the final polymerization cycle.

Clinical example.

Patient A., 27 years old. Complaints: food getting stuck in tooth 1.6, pain when eating solid food and from temperature irritants, which quickly passes after the irritant is removed.

Objectively: the general condition is satisfactory. A carious cavity filled with softened, pigmented dentin, as well as an old, failed filling, was found on the chewing surface of tooth 1.6 (Fig. 2). Probing along the cavity walls in the area of the enamel-dentin junction is painful. The carious cavity is Black class I. Percussion of tooth 1.6 is painless. The temperature test is positive, the reaction disappears within 2 seconds after removing the irritant. Diagnosis according to ICD-10: K02.1 Dentin caries of tooth 1.6.

Treatment: under application "DiSiLan" and infiltration anesthesia "Articaine, Binergia" 1.7 ml, 1:100000 (or Sol/Articani 1.7 ml, 1:100000), the carious cavity was prepared, necrectomy and finishing of the enamel edges were performed, medicated treatment of the cavity with a 2% solution of chlorhexidine bigluconate (Fig. 3). Selection and fitting of a counter stamp for tooth 1.6 (large size) from the system of universal occlusal counter stamps (Fig. 4). Next, the hard tissues of the teeth were etched with 37% orthophosphoric acid, adhesive preparation of the cavity was performed using the Solo Plus OptiBond adhesive system, dentin was sealed with SDR flowable composite (Dentsply), the dentin floor was restored with Harmonize Dentin D2 composite material (Kerr), and it was polymerized. Then, the final portion of Harmonize Enamel A2 composite material (Kerr) was introduced and distributed into the cavity, spreading it over the entire surface of the cavity (including the cusps), a PTFE membrane was applied, a pre-selected counter stamp was fitted, and the composite material was polymerized through the transparent layer of the counter stamp. Then, the counter stamp was removed and direct polymerization was repeated (Fig. 5). Grinding and polishing of the finished composite restoration.

The proposed method for filling carious cavities in the masticatory group using a universal system of occlusal counterstamps meets the requirements for aesthetic and functional direct composite dental restorations. This significantly improves the quality of conservative caries treatment and accelerates the process of shaping the functional chewing surface of teeth, which is especially relevant in outpatient municipal dental care and inpatient settings. Based on the study results, it can be concluded that the proposed invention is easy to use, cost-effective, and has no contraindications.

Claims (1)

A method for direct restoration of the chewing group of teeth using a system of occlusal counter-stamps, which consists in the fact that occlusal counter-stamps of the chewing group of teeth are manufactured, in which the average statistical parameters of the occlusal surfaces of the chewing group of teeth of the upper and lower jaws are calculated by measuring the occlusal surfaces in the mesiodistal and vestibulo-oral directions and determining the height of the tubercles, then, based on the obtained values, a set of counter-stamps of chewing teeth is made from photopolymer plastic, taking into account individual characteristics, including two size series, and upon completion of the preparation of the formed carious cavity for filling, the required size of the counter-stamp of the corresponding tooth is selected from the set of occlusal counter-stamps of the appropriate size series, its fitting is carried out, after verification of the required stamp, preparation is carried out by etching the enamel and dentin with 37% orthophosphoric acid gel for 30 and 15 s, and after After sealing the dentin with a flowable composite material and restoring the dentin floor, the final portion of the packable composite of the enamel shade is applied, then a polytetrafluoroethylene membrane is applied to the surface of the unpolymerized composite and the composite is pressed with a counter stamp to build up the cusps of the occlusal surface of the tooth, with the first polymerization being carried out through a transparent counter stamp, then the stamp with the membrane is removed and re-polymerization is carried out for 1 minute, thereby ensuring a highly accurate reproduction of the cusps of the chewing surface of the tooth.