Chemical stability of orthodontic adhesives based on polymer network depending on external environment's temperature/Stabilnosc chemiczna klejow ortodontycznych opartych na sieci polimerowej w zaleznosci od temperatury srodowiska zewnetrznego

In the present study the authors assessed chemical stability of four light-cured orthodontic adhesives: Contec LC, Transbond XT, Transbond Plus, Resilience, with respect to temperature of the external environment. Polymerized samples of orthodontic adhesives were treated with pH 7 phosphate-citrate buffer solutions based on HPLC-grade water at 20, 36 and 50[degrees]C. After 1 hour, 24 hours and 7 days of sample incubation, the obtained eluates were analyzed using the high performance liquid chromatography method (HPLC) which confirmed the presence of triethylene glycol dimethacrylate (TEGDMA) monomer in solutions obtained after incubation of Contec LC, Resilience and Transbond XT samples. The presence of ethylene glycol dimethacrylate (EGDMA) monomer was also detected in eluates obtained from the Resilience adhesive. The eluates obtained after storage of Transbond Plus adhesive system were free of the sought substances. TEGDMA monomer concentrations were highest in the eluates obtained after 1 hour of incubation, the lowest after 7 days of storage of orthodontic adhesive samples, regardless of the temperature of the phosphate-citrate buffer. In addition, there were statistically significant differences in concentrations of monomers depending on the tested adhesive system. The rate of degradation of orthodontic adhesives based on a polymer network may also be adversely affected by an increase in ambient temperature. Keywords: orthodontic adhesive systems, HPLC, chemical stability, monomers, temperature. Oceniano stabilnosc chemiczna czterech swiatloutwardzalnych klejow ortodontycznych: Contec LC, Transbond XT, Transbond Plus oraz Resilience w warunkach zmiennych wartosci temperatury srodowiska zewnetrznego. Spolimeryzowane probki klejow poddawano dzialaniu roztworow buforu fosforanowo-cytrynianowego na bazie wody o czystosci HPLC o pH 7 i temperaturze 20, 36 i 50[degrees]C. Po uplywie 1 h, 24 h i 7 dni inkubacji probek uzyskane eluaty analizowano metoda chromatografii cieczowej wysokocisnieniowej HPLC, ktora potwierdzila obecnosc monomeru dimetakrylanu glikolu trietylenowego (TEGDMA) w roztworach otrzymanych po inkubacji probek materialow Contec LC, Resilience i Transbond XT. W eluatach uzyskanych z kleju Resilience wykryto ponadto obecnosc monomeru dimetakrylanu glikolu etylenowego (EGDMA). Eluaty otrzymane po inkubacji systemu adhezyjnego Transbond Plus byly wolne od poszukiwanych substancji. Najwicksze stezenia monomeru TEGDMA byly w eluatach uzyskanych