title: The effect of two different calcium hydroxide combinations on root dentine microhardness.
abstract: OBJECTIVE
  To evaluate the effect of a calcium hydroxide and glycerine mix and a calcium hydroxide and water mix on the microhardness of human root dentine.
  
  
  METHODS
  Eleven freshly extracted maxillary canine and central incisor teeth were used. The teeth were sectioned transversally to produce a total of 22 dentine discs from the middle-third of the root. The specimens were divided into two groups of 11 discs each. Dentine samples were treated with either a Ca(OH)2-glycerine combination or a Ca(OH)2-distilled water combination for 1, 3 and 7 days. Dentine microhardness was measured with a Knoop indenter with a load of 100 g for 15 s before and during the experimental period. Each root disc received a series of three indentations around the pulp space, 1 mm from canal wall.
  
  
  RESULTS
  Statistical analysis showed that both combinations significantly decreased dentine microhardness after 3 and 7 days (P < 0.01). The reduction in dentine microhardness following the use of a Ca(OH)2-glycerine combination was significantly greater than that after a Ca(OH)2-distilled water combination after 3 and 7 days (P < 0.01).
  
  
  CONCLUSIONS
  The use of Ca(OH)2 combinations for intracanal dressing softens dentine.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Faculty of Dentistry, University of Cukurova, Adana, Turkey. oguzyoldas@cu.edu.tr
authors.forename: O
authors.initials: O
authors.lastname: Yoldaş
authors.forename: C
authors.initials: C
authors.lastname: Doğan
authors.forename: G
authors.initials: G
authors.lastname: Seydaoğlu
mesh_terms: D002126:Calcium Hydroxide / Q000737:chemistry / Q000494:pharmacology*; D003481:Cuspid; D003786:Dental Pulp Cavity / Q000187:drug effects; D003804:Dentin / Q000187:drug effects*; D005990:Glycerol / Q000737:chemistry / Q000494:pharmacology*; D006244:Hardness; D006801:Humans; D007180:Incisor; D008422:Materials Testing; D014677:Pharmaceutical Vehicles; D012387:Root Canal Filling Materials / Q000737:chemistry / Q000494:pharmacology*; D013314:Stress, Mechanical; D013997:Time Factors; D014092:Tooth Root / Q000187:drug effects*; D014867:Water
chemical_list: D014677:Pharmaceutical Vehicles; D012387:Root Canal Filling Materials; D014867:Water; D005990:Glycerol; D002126:Calcium Hydroxide