sealant, UltraSeal XT® hydro™ (Ultradent Products, USA), and to investigate its in vitro
resistance to microleakage after placement on conventionally acid etched and sequentially
lased and acid etched molars. Material and Methods: The sealant was characterised by
Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM),
energy dispersive X-ray analysis (EDX), and Vickers indentation test. Occlusal surfaces of
extracted human molars were either conventionally acid etched (n=10), or sequentially
acid etched and laser irradiated (n=10). UltraSeal XT® hydro™ was applied to both groups
of teeth which were then subjected to 2,500 thermocycles between 5 and 55°C prior to
microleakage assessment by fuchsin dye penetration. Results: UltraSeal XT® hydro™ is an
acrylate-based sealant that achieved a degree of conversion of 50.6±2.2% and a Vickers
microhardness of 24.2±1.5 under standard light curing (1,000 mWcm-2 for 20 s). Fluoride ion
release is negligible within a 14-day period. SEM and EDX analyses indicated that the sealant
comprises irregular submicron and nano-sized silicon-, barium-, and aluminium-bearing
reduce microleakage (Mann-Whitney U test, p<0.001). The lased teeth presented enhanced