title: Characterisation and microleakage of a new hydrophilic fissure sealant - UltraSeal XT® hydro™.
abstract: OBJECTIVE
  The aim of this study was to characterise the new hydrophilic fissure 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.
  
  
  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 filler phases embedded in a ductile matrix. Laser preconditioning was found to significantly reduce microleakage (Mann-Whitney U test, p<0.001). The lased teeth presented enhanced surface roughness on a 50 to 100 μm scale that caused the segregation and concentration of the filler particles at the enamel-sealant interface.
  
  
  CONCLUSIONS
  Laser preconditioning significantly decreased microleakage and increased enamel surface roughness, which caused zoning of the filler particles at the enamel-sealant interface.
authors.affiliation: - Erciyes Üniversitesi, Diş Hekimliği Fakültesi Pedodonti, Kayseri, Turkey.
authors.forename: Zeynep A
authors.initials: ZA
authors.lastname: Güçlü
authors.affiliation: - Bezmialem Vakıf Üniversitesi, Diş Hastalıkları ve Tedavisi, İstanbul, Turkey.
authors.forename: Nazmiye
authors.initials: N
authors.lastname: Dönmez
authors.affiliation: - University of Greenwich, Faculty of Engineering and Science, Kent, United Kingdom.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Hurt
authors.affiliation: - University of Greenwich, Faculty of Engineering and Science, Kent, United Kingdom.
authors.forename: Nichola J
authors.initials: NJ
authors.lastname: Coleman
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental; D003743:Dental Enamel / Q000187:drug effects* / Q000528:radiation effects; D003763:Dental Leakage / Q000517:prevention & control*; D005459:Fluorides / Q000737:chemistry; D006245:Hardness Tests; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008963:Molar; D010895:Pit and Fissure Sealants / Q000737:chemistry*; D015203:Reproducibility of Results; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D018709:Statistics, Nonparametric; D013499:Surface Properties / Q000187:drug effects / Q000528:radiation effects; D013997:Time Factors
chemical_list: D003188:Composite Resins; D010895:Pit and Fissure Sealants; C106663:Ultra Seal XT; D005459:Fluorides