RESEARCH OF PHYSICAL PROPERTIES OF PHOTOPOLYMERS AND THEIR USE IN DENTISTRY

Donetsk National Medical University

Obeida Mohamed Karim Youssef Mohamed, Lunhol Olha

Photopolymers are an important element in modern dentistry. The study of photopolymers in biophysics in the process of training medical students is an important component of the formation of professional competencies of future dentists. The study of photopolymers implements the following tasks of the discipline «Medical and Biological Physics» by the acquisition by students of professionally directed subject competencies: integral (ability to solve typical and complex specialized tasks and practical problems in occupational health care); general (ability to apply knowledge of medical and biological physics in practical situations, knowledge and understanding from other branches of science that form the basis of biological and medical physics etc.); special (professional) competencies (ability to replenish knowledge and understanding of the basic physical characteristics of medical and biological systems, physical bases of processes occurring in living organisms; ability to integrate basic knowledge in physics, chemistry, biology, mathematics, information technology in order to create the foundation of professional competencies).

Photopolymer is important in dentistry – as adhesives, sealing composites and protective coatings. Photopolymer materials are popular and fairly reliable filling materials in modern dentistry. Photopolymers provide durability and excellent aesthetics, which is achieved by the presence of a wide color gamut, identical in color and structure to the tooth. Photopolymer materials are used both for filling teeth and for their restoration. Modern dentistry offers a variety of high quality materials for photopolymer fillings.

According to general definition –  photopolymer or light-activated resin is a polymer that changes its properties when exposed to light, often in the ultraviolet or visible region of the electromagnetic spectrum. These changes are often manifested structurally, for example hardening of the material occurs as a result of cross-linking when exposed to light. Two physical phenomena invariably accompany the polymerization of resins of dental interest such as: the development of heat and the volumetric shrinkage of the cured material. The depth of cure for composite materials can be affected by several factors associated with the source of light polymerization, including spectral emission (wavelength distribution), light intensity, exposure period, irradiation distance and composition of composite material. Incomplete cure of the material leads to lower mechanical properties and wear performance; leakable residual monomer and color stability may decline as well. A lower degree of conversion also leads to degradation, substance loss and fracture, therefore, the lifespan of the restoration. Characteristics, such as composition of composite material, brand and shade, cavity preparation geometry and composite layer thickness, light intensity and polymerization time, can modify the final properties of material.

On the basis of the analysis of scientific articles and dissertations, it was established that the following composite light curing materials are widely used on the territory of Ukraine: Filtek Bulk Fill, Te-Econom, Estelite Equick, Latelux, Kollor, Spectrum and other.

To conclude, photopolymerization is a widely used technology, used in applications ranging from imaging to biomedical uses. Above is a description of just some photopolymerization applications, it has many prospects in the fields of dentistry, 3d printing photoresists and other medical uses.

REFERENCES

1. Photopolymer (light-activated resin). [Internet]. Available from: https://en.wikipedia.org/wiki/Photopolymer
2. The effect of insertion and photopolymerization techniques on microleakage of Class V cavities – a quantitative evaluation / Fabiana Mantovani Gomes FrançaI; Frederico Seidi HoriII; Alex José Souza dos SantosIII; José Roberto Lovadino // Restorative dentistry oral res. vol.19 no.1 São Paulo Jan./Mar. 2005. [Internet]. Available from:  http://dx.doi.org/10.1590/S1806-83242005000100006