title: The response of subcutaneous connective tissue to newly developed calcium phosphate-based root canal sealers.
abstract: OBJECTIVE
  To evaluate the histopathologic biocompatibility of two new calcium phosphate-based sealers (CPS-1 & CPS-2) with a commercially available calcium hydroxide-based sealer (Acroseal).
  
  
  METHODS
  Polyethylene tubes were filled with freshly mixed sealers and implanted subcutaneously in the dorsal connective tissue of rats. Empty tubes were used as controls. Histopathological examinations were conducted at 7, 15, 30, 60 and 90 days after the implantation procedure. The presence of inflammation and predominant cell types were analysed statistically with Mann-Whitney U and Kruskal-Wallis non-parametric tests. Fibrous connective tissue thickness adjacent to each sample was recorded. Differences were tested for significance using anova and 'Duncan's' multiple comparison test (P < 0.05).
  
  
  RESULTS
  CPS-1 sealer was associated with severe inflammation and remained an irritation throughout the 90-day implantation period; the tissue reaction pattern was stromal fibrosis. The control, CPS-2 and Acroseal sealers had similar patterns of irritation, which were more severe initially and diminished with time creating a thin fibrous capsule around the implant with a complete absence of inflammatory cells. There was no difference in tissue reaction between the control, CPS-1, CPS-2 and Acroseal groups amongst the first two observation periods (P > 0.05). However, there was a highly significant difference between the same groups at the last two observation periods (P < 0.01). Also, there were highly significant differences between the observation periods within all four groups at 7, 15, 30, 60 and 90 days (P < 0.01).
  
  
  CONCLUSIONS
  CPS-1 sealer was not biocompatible. CPS-2 sealer and Acroseal had a favourable biocompatibility level based on the histological findings.
authors.affiliation: Departments of Oral Biology, Medical College of Georgia, Augusta, GA 30912-1129, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Khashaba
authors.forename: M M
authors.initials: MM
authors.lastname: Moussa
authors.forename: N B
authors.initials: NB
authors.lastname: Chutkan
authors.forename: J L
authors.initials: JL
authors.lastname: Borke
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017610:Calcium Compounds / Q000633:toxicity; D002130:Calcium Phosphates / Q000633:toxicity; D017886:Durapatite; D007249:Inflammation / Q000139:chemically induced; D008297:Male; D008298:Maleates; D009336:Necrosis / Q000139:chemically induced; D010087:Oxides / Q000633:toxicity; D011095:Polyethylenes; D051381:Rats; D017207:Rats, Sprague-Dawley; D012387:Root Canal Filling Materials / Q000737:chemistry / Q000633:toxicity*; D018709:Statistics, Nonparametric; D040521:Subcutaneous Tissue / Q000187:drug effects*
chemical_list: C477053:Acroseal; D017610:Calcium Compounds; D002130:Calcium Phosphates; D008298:Maleates; D010087:Oxides; D011095:Polyethylenes; D012387:Root Canal Filling Materials; C485838:calcium phosphate, monobasic, anhydrous; C043105:poly(methyl vinyl ether-co-maleic anhydride); D017886:Durapatite; C016538:lime