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OPTIMIZATION OF PROSTHETIC FITTING OF FULL-CERAMIC RESTORATIONS IN DENTISTRY
Altai State Medical University, Barnaul Grokhotov I. O, Ubrayev R. Ye.
At the present time, all-ceramic restorations are widely used in dentistry. However, the technology of their manufacture is quite complex and requires a lot of a different materials.
One of the serious problems is the fitting of such restorations, especially veneers, which creates certain difficulties in assessing the final quality of the work. In connection with this, we developed a special gel for the fitting of such restorations, which was studied at the experimental stage.
It is established, that the gel is convenient in use, can be totally removed from the ceramic restoration surface, possesses a sufficient fixation strength and does not affect the color and other esthetic characteristics of veneers, which allows recommending it for the study at clinical trials. Key words: ceramic restorations, veneers, gel for temporary fixation.
Introduction
At present, all-ceramic restorations are widely used in dentistry, since they require minimum invasive preparation of the hard tooth tissue. In addition, the excellent properties of all-ceramic restorations, such as color stability, mechanical strength, compatibility with periodontal tissues, as well as pleasing aesthetics, allow them to be recommended for use in most clinical situations [1]. However, the technology of their manufacture is quite complex and requires a lot of a different materials [2]. One of the major problems is the fitting of such restorations, especially veneers, which are often not retained on the tooth, respectively, do not allow to accurately estimate their quality. Although it is very important to estimate the fitting quiescence, the marginal fit, the contact points density, the surface relief and the construction color of such restorations in a non-fixed form, and thereby make sure that we offer the patient the best result of orthopedic treatment [3]. We developed a special gel for the fitting of all-ceramic restorations (such as "Variolink II Try in"), but the use of them in Russia is difficult for several reasons:
- the gel is not licensed,
- it is not available in retail,
-its high cost [4].
Therefore, often, dental practitioners are forced to use auxiliary materials that are not designed for these purposes. Such process is incorrect and often inconvenient.
Research objective
In connection with the foregoing, our purpose was the development of a new gel for the fitting of all-ceramic restorations, using known and safe components for the oral cavity, comparable in quality with imported analogues.
Research tasks:
1. Analysis of literature data on the relevance and ways of solving the problem.
2. Development of the gel composition for the fitting of all-ceramic restorations.
3. Experimental approbation of the developed composition on the laboratory models.
4. Laboratory development of the final version of the optimal gel composition and its practical implementation.
Materials and methods
In order to determine the relevance of the problem, we conducted a survey of dentists who are engaged in the manufacture of ceramic restorations to determine what means they use to sample them, and also what problems they encounter during this stage.
The methods of investigation included in the experimental stage:
- checking the purity of the restoration after flushing the gel from its surface by staining the indicator;
- checking the adhesion of the restoration with the tooth during the fitting with the applied gel;
- determination of the color of the restoration with the applied gel in comparison with the analog and the initial state by means of hardware color determination with the Vita EasyShade instrument;
- determination of the general appearance of the restoration with gel applied under the control of a dental photograph.
As a means for fitting, we used a gel based on glycerin with a mineral filler.
The object of the study was: experimental models in the form of ceramic restorations, as well as a extracted tooth with ceramic veneer made on it.
Results and discussion
In the course of our research there was held an anonymous questionnaire poll among the dentists in Barnaul. Based on the analysis of its results, it is established that 41% of prosthodontists face problems during the testing of all-ceramic restorations. As for the materials used in this clinical stage, only 19% use "Variolink ll Try in" specifically designed for this purpose. 19% use additional materials not intended for fitting, for example: cream-gel Korega, correcting mass from Speedox, YETI Dental spray, ultrasound gel.
Unfortunately, 21% of dentists do not use any materials for fitting, in their opinion, because of the lack of materials, or their high cost. Thus, only 19% of physicians use specialized means for testing all-ceramic restorations at clinical stages. The overwhelming majority of doctors would
like to use a new domestic composition for fitting veneers, if they had the opportunity.
As a composition for the fitting of all-ceramic veneers, we used a water-soluble gel developed by us, including an inorganic filler dissolved in a glycerol base. According to its physicochemi-cal properties, the gel was adapted for use according to the existing analog.
Hereafter, to determine the ease of removing the gel after application, there was given an indication of its flushing from the surface of the restoration under running water after its preliminary application with an exposure time of 5 min. After that, the surface was painted with an indicator, followed by rinsing with a different time interval.
The method showed that the gel is washed off with a gap of 30 seconds completely without residue of the indicator, therefore it can not affect other materials used for adhesive fixation (Figure 1).
Figure 1. The indication of the purity of rinsing the gel from the restoration surface
The next step was to determine the strength of the gel fixation, for this purpose we compared the developed gel with the analogue "Variolink II try in". The figure provides a photograph that clearly shows the essence of the experiment, which proves that each material is able to keep the veneer from being displaced with an application of a certain weight. The maximum results for the Vario-link are 3 grams, for our gel the volume estimates 8 grams. Thus, it can be concluded that the adhesion strength of the gel to tooth surfaces and restoration is sufficient, somewhat exceeding the import analogue.
Further, we carried out a comparative assessment of the color of the restoration on a laboratory model by using Vita Easyshade. To do this, we initially determined the color of the restoration without any materials (result B1 OM3), then we determined the color of the restoration with the Vari-olink material (result A1 OM3). The gel developed
by us showed the result (B1 OM3), which coincides with the initial one and proves the absence of the effect of the agent on the color of the ceramic restoration. This result is very significant, because the color change during the fitting leads to an incorrect evaluation of the final result, and, ultimately, to the patient's negative perception of the work of the dentist.
The analysis of dental photographs showed that our gel does not affect the appearance of the restoration in comparison with the analog ("Varyolink Tray In"), and also when fitting without gel, no does it affect the color of the ceramic veneer and its attachment to the tooth.
Conclusion
Thus, according to the result of the questionnaire, the problem we are studying is relevant for dental practitioners, since most of them in Barnaul use materials that are not intended for fitting
ceramic restorations, or do not use any solutions at all.
The experimental testing of the developed gel allows us to conclude that it is effective and safe.
It is established that the gel is convenient for fitting all-ceramic reconstructions, has sufficient fixation force, does not affect the color and other characteristics of the restoration, which allows an objective assessment of its quality. We plan to continue our clinical research with this gel.
References
1. Kulakov A.A., Gvetadze R.Sh., Krechina Ye.K., Guseva I.Ye. Modern technologies in dentistry. Bulletin of Roszdravnadzor. 2009; 6: 55-60.
2. Zholudev D.S. Ceramic materials in prosthetic dentistry. Actual problems in dentistry. 2012; 5: 8-14.
3. Vartanov T.O. The basic stages of introduction of technology of metalless designs in the practice of stomatologist. Siberian medical journal. 2012; 4: 102-104.
4. Kitayeva T.A., Danilina T.F., Salyamov H.Yu., Verstakov D.V. Modern technologies for making structures from nonmetallic ceramics. On-line Scientific & Educational Bulletin "Health & education millennium". 2010; 8: 408-409.
Contacts
Corresponding author: Grokhotov Ilya Olegov-ich, Candidate of Medical Sciences, Associate Professor of the Department of orthopedic dentistry of ASMU, Barnaul. 656038, Barnaul, Lenina Prospekt, 40. Tel.: 8-913-023-57-36. E-mail: ilident@yandex.ru
