engleski

Polymerisation rate of various orthodontic adhesive systems in relation to curing time

AIM: The aim of this study was to assess the degree of conversion of orthodontic adhesive systems of different chemical composition in relation to two curing times. MATERIALS AND METHODS: Four adhesives, four respective primers and four adhesive-primer combinations were tested: light-cure Transbond Plus adhesive and Transbond XT primer (3M Unitek, USA), Light Bond Paste (LB) adhesive, Light Bond Sealant primer, Light Bond Paste With Fluoride (LBF) adhesive, Light Bond Sealant With Fluoride primer (Reliance Orthodontic Products Inc., USA) and the dual-cure Geristore® adhesive and Tenure® primer (DenMat, USA). The Bluephase Syle curing unit (Ivoclar Vivadent, Liechtenstein) was used for illuminating ten specimens of each adhesive, primer and adhesive-primer combination at 1100 mW/cm2 for 10 and 20 seconds in a simulation of the clinical bonding procedure under a metal premolar bracket, totaling 240 samples. In assessing the degree of conversion (DC) of the specimens, Fourier transform infrared spectroscopy was used. Analysis of variance and the Student-Neuman-Keuls post-hoc test were used for statistical analysis. RESULTS: Geristore® adhesive showed significantly higher DC than all other adhesives, primers and adhesive-primer combinations after 10 seconds of illumination (68.96±4.22 ; p<0.05). Tenure® primer had significantly lower DC than other primers (41.54±7.73 ; p<0.05). The LBF adhesive-primer combination showed significantly lower DC (51.72±4.71) than the LB combination (60.32±7.62 ; p<0.05), however, after 20 seconds, they did not differ significantly. Transbond Plus adhesive showed the lowest DC among adhesives after 10 seconds of illumination (47.58±3.67) and after 20 seconds this difference was significant (50.75±3.45 ; p<0.05). In general, DC was higher after 20 seconds than after 10 seconds of illumination. After 20 seconds, the highest DC was accomplished in the Geristore-Tenure® combination (74.97±3.80), which was significantly higher than all other systems except for the Transbond Plus adhesive-primer combination (70.40±4.01 ; p<0.05). DC decreases in following order: Geristore-Tenure®20 > Transbond Plus20 > LB20 > Transbond Plus10 > LBF20 > LB10 > Geristore-Tenure®10 > LBF10. CONCLUSION: Longer illumination time increases the DC of orthodontic adhesive systems. Lower DC might have repercussions on bond strength and cyto- and genotoxicity.

polimerisation ; orthodontics ; adhesives

Potpora Sveučilišta u Rijeci projektu 13.06.2.1.53