title: Influence of cavity preparation with Er,Cr:YSGG laser and restorative materials on in situ secondary caries development.
abstract: OBJECTIVE
  The aim of this study was to evaluate the influence of cavity preparation and restorative materials containing fluorides in the prevention of secondary caries lesion development in situ.
  
  
  METHODS
  A total of 120 blocks obtained from human teeth were divided into two groups and standardized cavities were prepared using diamond burs (DB) or Er,Cr:YSGG-laser [20 Hz, 4.0W, 55% water, 65% air (LA)]. They were divided into three subgroups according to the restorative material (n=20): glass-ionomer cement (GI), resin modified glass-ionomer (RM) or composite resin (CR). Blocks were fixed in palatal intra-oral appliances worn in situ by 20 human volunteers, who dropped 20% sucrose solution eight times daily. After 21 days, blocks were removed and restorations were cross-sectioned to evaluate microhardness [Knoop hardness number (KHN)] underneath enamel surface from 30 to 200 μm. Factors "cavity preparation," "restorative materials," and "depth" were evaluated by three way ANOVA, followed by Tukey test (p<0.05).
  
  
  RESULTS
  The results showed lower microhardness in cavities prepared with DB than in cavities prepared with LA. At 30 μm, there were no statistical significant differences with regard to "cavity preparation" or "restorative materials" factors. In depth evaluation, the enamel microhardness progressively increased as a function of depth for the GI groups. In the groups prepared with LA at 60 μm/90 μm, there were no significant differences between GI and RM materials, whose microhardnesses were significantly higher than that of CR.
  
  
  CONCLUSIONS
  Cavity preparation using Er,Cr:YSGG laser increases caries resistance of enamel walls, and reduce caries lesion depth development regardless of fluoride presence in the restorative material. CR showed higher caries lesion development than GI, and RM showed intermediate results.
authors: 1 Dental Research and Graduate Studies Division, Department of Restorative Dentistry, Guarulhos University , Guarulhos, SP, Brazil .
authors: Ana Carolina Tedesco
authors: AC
authors: Jorge
authors: Alessandra
authors: A
authors: Cassoni
authors: Patrícia Moreira
authors: PM
authors: de Freitas
authors: André Figueiredo
authors: AF
authors: Reis
authors: Aldo
authors: A
authors: Brugnera Junior
authors: Jose Augusto
authors: JA
authors: Rodrigues
mesh_terms: D003188:Composite Resins; D003731:Dental Caries / Q000517:prevention & control*; D003737:Dental Cavity Preparation / Q000379:methods*; D005899:Glass Ionomer Cements; D006801:Humans; D053844:Lasers, Solid-State; D028022:Low-Level Light Therapy; D046509:Tissue Culture Techniques
chemical_list: D003188:Composite Resins; D005899:Glass Ionomer Cements
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