MOSCOW, Sep 4UrFU scientists as part of a research team have shown that in fundamental dentistry it is possible to use a material based on the shell of chicken eggs. In their opinion, the eggshell is similar in properties to tooth enamel, so it can be used as a model material for testing the cohesive strength of the polymer filling-tooth connection. The results of the work were published in the Journal of Composites Science.
Dentistry is one of the most expensive areas of medicine for patients due to the prices of equipment for dental clinics and medicines, including restorative materials used to make fillings and dental components. implants.
July 1, 08:00
Strict requirements are imposed on restorative materials in dentistry. Firstly, it is a high biocompatibility with the human body. Secondly, the strength of the fillings and implants made from them should not be higher than the strength of the tooth itself, otherwise healthy teeth will be destroyed upon contact with the filling or implant. Thirdly, the low cost of restorative materials, which will make them more accessible to a wide range of patients. Federal University named after the first President of Russia B.N. Yeltsin (UrFU). Most modern filling materials used in clinical practice are based on the polymer polymethyl methacrylate.
The filling should be easily and quickly applied to the sanitized area of the diseased tooth and firmly adhere to it, despite the considerable mechanical stress that occurs when chewing food. To evaluate the cohesive strength of the connection between the filling and the tooth, a large amount of experimental material is required, which is close in physical and mechanical properties to the hard tissues of human teeth (dentin and enamel).
Tooth enamel is the hardest tissue in the human body. It covers the protruding part of the tooth above the gum – the crown, protecting the hard base of the tooth (dentin) from damage. According to its chemical composition, enamel is calcium apatite of biological origin – a complex chemical compound of phosphorus, calcium and oxygen with a certain amount of fluorine and chlorine. Therefore, scientists are looking for a replacement for natural enamel among biominerals with a similar chemical composition and strength properties.
According to scientists, it is not enough just to find such a material – it is necessary to conduct detailed laboratory studies, which is associated with high search and selection costs experimental biomaterial (human teeth), including obtaining permission from the relevant ethics committee; preparation of samples from tooth enamel and application of filling material on them; for mechanical testing of small-sized samples and their metallographic certification.
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The team of the Institute of Natural Sciences and Mathematics of the Ural Federal University, together with specialists from the Ural State Mining University and the Ural State Medical University, found that calcium carbonate of biological origin – chicken egg shell – can serve as a substitute for enamel in assessing the cohesive strength of the connection between a polymer filling and a tooth, while meeting the criteria on which the restorative dental material is evaluated.
“Chicken eggshell has two big advantages over other biominerals: its thickness is almost constant in all parts of the egg and it has two natural lateral surfaces that are similar in morphology to the surface of tooth enamel, which allows mechanical tests to be carried out according to the three-point bending scheme, allowing to evaluate cohesive strength of the connection of two different materials,” said Petr Panfilov, Professor of the Department of Condensed Matter Physics and Nanoscale Systems, UrFU. “ar16x9″ data-crop-ratio=”0.5625″ data-crop-width=”600″ data-crop-height=”338″ data-source-sid=”not_rian_photo” class=”” />
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According to him, the concave surface of the eggshell makes it possible to reliably assess the ability of the polymer coating to adhere to the enamel. Given the availability and low cost of eggshells, the new technique can be used in the training of dentists, when the head of the practical session can evaluate the work of the trainee in installing the seal both visually and by the results of mechanical tests.
“The use of samples from chicken egg shells makes it possible to speed up the preliminary selection of filling materials formulations so that expensive tests on enamel-filling composites can be carried out only on the most promising materials with the required functional properties and maximum cohesive strength. And such compositions can be used in the future when conducting preclinical and clinical experiments,” Panfilov said.
In the future, the team plans to develop guidelines for applying filling material to chicken egg shell samples and conducting mechanical tests according to the three-point bending scheme for training dentists.
This work was supported by the Russian Foundation for Basic Research in cooperation with the Government of the Sverdlovsk Region (grant no. 20-48-660017) and the Russian Science Foundation (grant no. 23-29-00253).
UrFU is a participant of the Priority-2030 state support program for universities of the Russian Federation.
