title: Effect of artificial aging on the bond durability of fissure sealants.
abstract: OBJECTIVE
  To evaluate the effect of artificial aging on the bond durability of fissure sealants in vitro.
  
  
  METHODS
  Twenty bovine incisors received 4 different sealant treatments and were divided into four groups: 1. Ultraseal XT plus (UX); 2. Enamel Loc (EL); 3. 35% phosphoric acid plus Enamel Loc (PEL); 4. Adper Prompt L-Pop plus Clinpro (PPC). Beam-shaped specimens were prepared and randomly divided into three subgroups. One subgroup underwent the microtensile bond strength (µTBS) test after 24-h storage in 37°C water. The other two subgroups were also subjected to the microtensile bond strength test after 5000 and 10,000 thermal cycles, respectively. Another twelve intact human third molars were sealed using 1 of 3 methods and were divided into 3 groups of 4 each: 1. Ultraseal XT plus; 2. Adper Prompt L-Pop plus Clinpro; and 3. Enamel Loc. Two specimens from each group were immersed in a 50% silver nitrate solution for 24 h, followed by exposure to fluorescent light for 8 h, before being scanned in a micro-CT (microcomputer tomography) machine. The other two were handled in the same way after undergoing 10,000 thermal cycles. The CT images obtained were evaluated.
  
  
  RESULTS
  All samples from the EL group were broken during preparation, so no µTBS results were available. After 5000 thermal cycles, the bond strengths of the three other groups (UX, PEL, PPC) decreased significantly (p < 0.05). Longer thermocycling (10,000 cycles) resulted in more decreases in µTBS for group PEL and PPC, while the strength of the UX group remained relatively unchanged. After thermocycling, considerable silver penetration could be seen at the sealant/enamel interface of the EL group in micro-CT images.
  
  
  CONCLUSIONS
  The etch-and-rinse procedure for sealant application promotes higher bond strength under artificial aging. Micro-CT, a nondestructive analytical tool, may be used to evaluate the sealant/enamel interface effectively.
authors.affiliation: West China College of Stomatology, Sichuan University, Chendu, Sichuan, China. schaffer.yun@gmail.com
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Yun
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Chen
authors.initials: C
authors.lastname: Ling
authors.forename: Alex
authors.initials: A
authors.lastname: Fok
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000818:Animals; D002417:Cattle; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure; D006801:Humans; D008027:Light; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects; D010756:Phosphoric Acids / Q000737:chemistry; D010895:Pit and Fissure Sealants / Q000737:chemistry* / Q000528:radiation effects; D011092:Polyethylene Glycols / Q000737:chemistry / Q000528:radiation effects; D011109:Polymethacrylic Acids / Q000737:chemistry / Q000528:radiation effects; D011140:Polyurethanes / Q000737:chemistry; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry / Q000528:radiation effects; D016622:Silver Staining; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry; D055114:X-Ray Microtomography
chemical_list: C500418:Clinpro Sealant; D003188:Composite Resins; D008689:Methacrylates; D010756:Phosphoric Acids; D010895:Pit and Fissure Sealants; D011109:Polymethacrylic Acids; D011140:Polyurethanes; C408584:Prompt L-Pop; D019279:Resin Cements; C106663:Ultra Seal XT; D014867:Water; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; C034139:4-methacryloxyethyltrimellitic acid anhydride; C030242:phosphoric acid