title: Tecidual reaction of calcium hydroxide front chronic stress histological study in rats.
abstract: BACKGROUND
  The Calcium Hydroxide has been widely used as an intracanal dressing and in combination with restorative and endodontic materials and its main goal is the tissue reparation. However, when the patient has chronic stress, the immunological response and tissue repair decreases in both the epithelial and connective tissue. Therefore, the aim was to analyze the effect of chronic stress on the tissue response in rats exposed to calcium hydroxide (CH).
  
  
  METHODS
  A total of 60 wistar rats were anesthetized, and a polyethylene tube containing CH was inserted under the skin. After 24 h, they were divided into two groups: Calcium hydroxide + stress (CHSG) n = 30 and calcium hydroxide (CHG) n = 30. They were stressed by physical restraint, for 12 h each day for periods of 7, 15 and 30 days when 10 animals from each group were euthanized. The tissues surrounding the polyethylene tubes were removed, and slides were prepared and stained with hematoxylin and eosin. The analysis was performed with an optical microscope with magnification of 4-400 times by a blinded senior examiner. The sample slides were classified according to the following scores 0 - absent/1 - present/2 - infiltrate to: Inflammatory infiltrate containing fibrous condensation, lymphocytes, plasmacytes, macrophages, neutrophils, and eosinophils. The data were statistically analyzed using the Student's t-test (P < 0.05) for paired samples.
  
  
  RESULTS
  The exposure time of 7 days elicited no statistical difference between groups (P > 0.05). The 15 days exposure group had higher averages for CHG to eosinophils and inflammatory infiltrate (P < 0.05). In 30 days, CHG showed higher averages to inflammatory infiltrate and lower averages to FC (P < 0.05).
  
  
  CONCLUSIONS
  Some modified patterns of responses in the CHSG were observed at 15 days and 30 days.
authors.affiliation: Professor, Department of Master Program in Integrated Dentistry Science, University of Cuiabá-UNIC, Cuiabá, MT, Brazil.
authors.forename: Tereza Aparecida Delle Vedove
authors.initials: TA
authors.lastname: Semenoff
authors.affiliation: Professor, Department of Master Program in Integrated Dentistry Science, University of Cuiabá-UNIC, Cuiabá, MT, Brazil.
authors.forename: Evanice Menezes Marçal
authors.initials: EM
authors.lastname: Vieira
authors.affiliation: Professor, Department of Master Program in Integrated Dentistry Science, University of Cuiabá-UNIC, Cuiabá, MT, Brazil.
authors.forename: Alvaro Henrique
authors.initials: AH
authors.lastname: Borges
authors.affiliation: Professor, Department of Master Program in Dentistry, CEUMA University-UniCEUMA, São Luis, Brazil.
authors.forename: Matheus Coelho
authors.initials: MC
authors.lastname: Bandeca
authors.affiliation: Student, Department of Master Program in Dentistry, CEUMA University - UniCEUMA, São Luis, Brazil.
authors.forename: Reidson Stanley Soares
authors.initials: RS
authors.lastname: Dos Santos
authors.affiliation: Professor, Department of Master Program in Integrated Dentistry Science, University of Cuiabá-UNIC, Cuiabá, MT, Brazil.
authors.forename: Fábio Luis Miranda
authors.initials: FL
authors.lastname: Pedro
authors.affiliation: Undergraduate Student of Biology, Department of Biology, University of Cuiabá (UNIC), Cuiabá, MT, Brazil.
authors.forename: Natalino Francisco
authors.initials: NF
authors.lastname: da Silva
authors.affiliation: Professor, Department of Master Program in Integrated Dentistry Science, University of Cuiabá-UNIC, Cuiabá, MT, Brazil.
authors.forename: Alex
authors.initials: A
authors.lastname: Semenoff-Segundo
keywords: Calcium hydroxide; laboratory study; rats; stress