title: Effect of operator skill in relation to microleakage of total-etch and self-etch bonding systems.
abstract: OBJECTIVE
  To evaluate the influence of operator skill on microleakage in class V restorations using two-step bonding systems.
  
  
  METHODS
  Two standardized box cavities were made on the buccal and lingual surfaces of 54 human bicuspid teeth, with the cervical margin in dentin. The teeth were randomly assigned to two groups according to the operator's skill. Students group: undergraduate students. Expert group: a dentist with 20 years of clinical experience in dental adhesion. The buccal cavities of each tooth were treated with Prime&Bond NT (two-step total-etch system); the lingual cavities were treated with AdheSE (two-step self-etch system). All cavities were restored by a single calibrated operator with one bulk increment of resin composite (InTens; Ivoclar Vivadent). Specimens were thermocycled, immersed in 2% methylene blue and sectioned in a bucco-lingual plane in the middle of the restorations. They were then examined under a stereomicroscope and scored according to microleakage by two operators who were blind to the specimen preparation. The data was subjected to a multilevel statistical model.
  
  
  RESULTS
  The microleakage resulting from the self-etch adhesive was similar in the student and in the expert groups. On the other hand, the total-etch adhesive microleakage within the expert group resulted lower than that within the student group. However, the interaction term skill x adhesive resulted statistically significant at the dentin margin (p=0.0474) but not at the enamel margin (p=0.1267).
  
  
  CONCLUSIONS
  While the total-etch adhesive used in this study showed to be skill-sensitive, the self-etch one proved to be less skill-sensitive in obtaining a reliable seal with dentin.
authors.affiliation: Department of Dentistry, Faculty of Medicine and Surgery, University of Florence, Florence, Italy. l.giachetti@odonto.unifi.it
authors.forename: Luca
authors.initials: L
authors.lastname: Giachetti
authors.forename: Daniele
authors.initials: D
authors.lastname: Scaminaci Russo
authors.forename: Fabio
authors.initials: F
authors.lastname: Bertini
authors.forename: Felicita
authors.initials: F
authors.lastname: Pierleoni
authors.forename: Michele
authors.initials: M
authors.lastname: Nieri
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000180:Acrylic Resins / Q000737:chemistry; D001641:Bicuspid; D002983:Clinical Competence; D003763:Dental Leakage / Q000517:prevention & control*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D003815:Dentists; D006801:Humans; D015588:Observer Variation; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D013335:Students, Dental
chemical_list: D000180:Acrylic Resins; C489662:AdheSE cement; D017220:Dentin-Bonding Agents; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; D019279:Resin Cements