Comparison of Fluorescence of Tooth Enamel, Resin Composite, Lithium Disilicate and Monolithic Zirconia Under Thermocyclic Ageing

Abstract

The aim was to compare the fluorescence intensity of tooth enamel, resin composite, lithium disilicate, and monolithic zirconia before and after thermocyclic aging. Lithium disilicate (LD) and monolithic Zirconia ceramic samples were fabricated with the CAD-CAM method. Resin composite specimens, of shades A1, A2, and A3, were prepared with photo-polymerization and putty mold. Extracted second molar teeth were obtained and sectioned to produce enamel specimens. Fluorescence assessment prior to thermocycling was performed using flurolog-Qm system before and after thermocycling. Samples were exposed to thermocycling (TC) for 30,000 cycles in distilled water at 5 °C and 55 °C for 30 s each, with 5 s between the baths. The means and standard deviations were compared using, t-test, analysis of variance, and Tukey–Kramer multiple comparisons test. The initial fluorescence intensities before thermocyclic ageing were highest in LD ceramic specimens (42579±817.1). The lowest fluorescence was observed in monolithic Zr specimen 14750±584.7. The reduction in fluorescence intensity after thermocyclic ageing was highest in LD specimens, however, the lowest difference was noted in composite A3 specimens. LD ceramic showed significantly high fluorescence among all materials before and after ageing. The fluorescence of the tested materials reduced with ageing and is expected to decrease intraorally with time.