title: Biocompatibility of root filling pastes used in primary teeth.
abstract: OBJECTIVE
  To evaluate the biocompatibility of two pastes designed to fill the root canals of primary teeth.
  
  
  METHODS
  A study group of 54 mice received subcutaneous tissue implants of polyethylene tubes containing CTZ or calcium hydroxide paste or, as a negative control, empty tubes. Biocompatibility was evaluated on days 7, 21 and 63, yielding a total of nine groups of six animals each. Following the experimental intervals, the implant areas were removed and subjected to histologic processing. After the tissues were stained with HE and Masson trichrome, two pathologists performed a histologic analysis of the samples in a blinded manner. Collagen fibre formation, tissue thickness and inflammatory cell infiltration were analysed qualitatively. Quantitative morphometry was performed for the thickness, perimeter length and tissue area of the region in direct contact with the open tube. anova with the Tukey post-test and Kruskal-Wallis analysis followed by Dunn's post-test, with significance established as P < 0.05, were used for data analysis.
  
  
  RESULTS
  At 7 days, all groups had severe acute inflammatory infiltrates. Inflammation was reduced at 21 days in the CTZ paste group. Mild chronic inflammatory infiltrates were observed after 63 days in the CTZ and Ca(OH)2 paste groups; these groups also showed a significant decrease in collagen fibre density (P < 0.05), which was not observed in the control group. The average tissue thickness, perimeter length and area in contact with the tube decreased during the experimental periods in all groups.
  
  
  CONCLUSIONS
  The CTZ and calcium hydroxide pastes demonstrated biocompatibility with subcutaneous tissue in this experimental model.
authors.affiliation: Postgraduate Programme in Dentistry, Federal University of Piauí (UFPI), Teresina, Brazil.
authors.forename: C C B
authors.initials: CC
authors.lastname: Lima
authors.forename: A M
authors.initials: AM
authors.lastname: Conde Júnior
authors.forename: M S
authors.initials: MS
authors.lastname: Rizzo
authors.forename: R D
authors.initials: RD
authors.lastname: Moura
authors.forename: M S
authors.initials: MS
authors.lastname: Moura
authors.forename: M D M
authors.initials: MD
authors.lastname: Lima
authors.forename: L F A D
authors.initials: LF
authors.lastname: Moura
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D002126:Calcium Hydroxide / Q000494:pharmacology*; D002701:Chloramphenicol / Q000494:pharmacology*; D004338:Drug Combinations; D008297:Male; D051379:Mice; D012387:Root Canal Filling Materials / Q000494:pharmacology*; D040521:Subcutaneous Tissue / Q000187:drug effects; D013752:Tetracycline / Q000494:pharmacology*; D014094:Tooth, Deciduous / Q000601:surgery*; D015034:Zinc Oxide / Q000494:pharmacology*
chemical_list: D001672:Biocompatible Materials; D004338:Drug Combinations; D012387:Root Canal Filling Materials; D002701:Chloramphenicol; D013752:Tetracycline; D002126:Calcium Hydroxide; D015034:Zinc Oxide
keywords: biocompatibility; calcium hydroxide; primary teeth; root canal filling materials; subcutaneous tissue