title: [In vitro evaluation of the cytotoxicity of composite resin in the presence or absence of smear layer].
abstract: BACKGROUND
  The aim of the present research was to investigate the cytotoxicity of the composite resins applied on dentine samples with different smear layer removal, by using cell cultures and LDH determination.
  
  
  METHODS
  Ninety-eight caries-free third molars recently extracted were used. Transversal sections, 500 mu thick, were obtained. A simulated pulpar chamber was constructed allowing to give lodging in the inferior side to the cell culture and in the superior side to the dentine section with the composite resin. LDH activity was then determined by using a spectrophotometer.
  
  
  BACKGROUND
  The results show that the composite resins are surely cytotoxic if directly applied on the dentine. The smear layer is able to reduce the transdentinal diffusion of composite resin toxicity. On the basis of the data obtained it is suggested that in vivo, being necessary to eliminate the smear layer due to its bacterial contents, it is possible in the deep cavities, to partially remove with EDTA maintaining the smear plugs after their disinfection. Nevertheless EDTA application should not exceed 30 seconds.
authors.affiliation: Cattedra di Odontoiatria Conservatrice, Università degli Studi, Torino.
authors.forename: M
authors.initials: M
authors.lastname: Pezzoli
authors.forename: P
authors.initials: P
authors.lastname: Baldi
mesh_terms: D018929:Cell Culture Techniques; D003188:Composite Resins / Q000633:toxicity*; D003601:Cytotoxicity Tests, Immunologic; D003786:Dental Pulp Cavity; D003804:Dentin / Q000187:drug effects*; D006801:Humans; D007770:L-Lactate Dehydrogenase; D008964:Molar, Third; D013053:Spectrophotometry
chemical_list: D003188:Composite Resins; D007770:L-Lactate Dehydrogenase