title: An in vitro comparison of fluorescence-aided caries excavation and conventional excavation by microhardness testing.
abstract: OBJECTIVE
  The aim of this in vitro study was to compare fluorescence-aided caries excavation with conventional excavation based on the Martens and Vickers hardness of dentin at the cavity floor after caries removal.
  
  
  METHODS
  In total, 20 extracted human teeth with dentin caries were bisected through the lesion center into two halves, which were assigned to either the fluorescence-aided caries excavation group or the conventional excavation group. After the treatment, embedding, mounting, and polishing, a line of indentations from the dental pulp across the sound dentin to the cavity floor was made on each sample. The data were compared with Student's t and Mann-Whitney U tests.
  
  
  RESULTS
  The calculated Vickers hardness of the sound dentin was 57 ± 10 kg/mm(2) in the fluorescence-aided caries excavation group and 59 ± 8 kg/mm(2) in the conventional excavation group, which is consistent with the previous studies. The absolute and relative Martens hardness measurements of the cavity floor were 224 ± 93 N/mm(2) and 46 ± 17%, respectively, in the fluorescence-aided caries excavation group and 412 ± 75 N/mm(2) and 81 ± 14%, respectively, in the conventional excavation group. Based on either the Martens or Vickers hardness, both the absolute and relative microhardness measurements of the cavity floor after fluorescence-aided caries excavation were significantly lower than the values obtained by conventional excavation.
  
  
  CONCLUSIONS
  Fluorescence-aided caries excavation showed the tissue-preserving property and was more conservative than the conventional excavation in this in vitro study.
authors.affiliation: Department of Endodontics and Operative Dentistry, Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China, guangyunlai@hotmail.com.
authors.forename: Guangyun
authors.initials: G
authors.lastname: Lai
authors.forename: Laikuan
authors.initials: L
authors.lastname: Zhu
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Xu
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Kunzelmann
mesh_terms: D003731:Dental Caries / Q000601:surgery*; D005453:Fluorescence; D006244:Hardness; D006801:Humans; D066298:In Vitro Techniques