I.J.Poyurovskaya
Choice of effective and reliable material for teeth restoration is not an easy task, especially now when numerous brands of filling materials are being offered to a practicing dentist by foreign companies and national producers. What principles should one follow while choosing a material? Perhaps the most convincing argument in favor of one or another restorative material would be positive result of its clinical tests, based on detailed analysis of clinical observations. However, such tests are not sufficient, and many brands of composite filling materials, entering Russian market are not known in mass practice.
The above said explains the growing role of pre-clinical or in vitro tests of restoration materials, which allow to evaluate objectively their technical characteristics exerting substantial influence on the effectiveness of clinical use of materials. In the research centre of dental materials «Matiss» on the basis of department for materials technology of Central Research Dentistry Institute comparative tests of 6 brands of filling materials of national and foreign production have been made. All materials are self-cure composites of pasta-pasta type in accordance with international standard ISO 4049. The presented materials belong to Class B and Type I. The lost of material samples and their short characteristics are given in Table 1. The tests results have been drawn in Table 2 (a,b).
As may be seen from Table 2a, nationally-produced materials as to their basic physical and mechanical properties are not inferior to foreign analogues, and in many cases are superior to them. The samples of Prizma (producer JSC «StomaDent») have shown the highest diametric flexural strength and compressive strength. Only for this material, as has been established, flexural strength corresponds to ISO 4049 requirements. High strength characteristics have also materials Esterfill (JSC «DIAS») and Compodent (JSC «Stomachim»).
Out of tested foreign materials preference may be given to Compozite of Alpha-Dent (USA), which besides good strength characteristics has also better, than other materials, manipulative properties, sufficient working time, convenience by mixing and homogeneity. The lowest strength qualities and working characteristics have been detected for Zenith material.
Comparative analysis of adhesive properties of filling materials samples with regard to their bond to hard tooth tissues carried out in accordance with the technique of Central Research Dentistry Institute has shown approximately similar level of adhesive strength for all materials with some advantage of foreign Compozite and Compolite. Nationally-produced materials have a little lower level of adhesive strength, however this parameter tends to have more reliable values with lower deviation from average level. It is interesting to note that Esterfill material, when used together with sublayer Splad instead of adhesives, has shown a good level of adhesive strength, not inferior to other analogues.
The results of comparative tests of filling materials samples give impression only about their technical characteristics. At the same time the data received allows to draw a number of conclusions which may be important for clinical practice:
- Non in all cases of teeth restoration one should give preference to foreign materials. In many cases, when esthetic qualities of the seal are not a priority, nationally-made materials may provide more reliable restoration;
- When buying composite filling materials, as well as other dental materials, one should find out if quality certificate for this material is available. The certificate guarantees that dental material corresponds to main requirements and parameters of use, and that doctor will be insured against buying low quality material. Filling material Zenith of Foremost Dental Mfg., USA, may serve as an example of such material;
- For composite self-cure filling materials an important parameter from the practical point of view is working time. Working time is the period from the moment of mixing to the moment when solidification reaction starts. Usually this period is quite short, for the tested group of materials it is less than 2 minutes. In this respect light-cure restorative materials have indisputable advantages, as they are solidified, figuratively speaking, «by command».
