title: An evaluation of the effect of non-setting calcium hydroxide on human dentine: a pilot study.
abstract: OBJECTIVE
  To evaluate the effect of non-setting calcium hydroxide (NSCH) on the hardness and elastic modulus of dentine from extracted permanent premolar human teeth.
  
  
  METHODS
  30 freshly extracted single rooted human premolar teeth were decoronated and the roots then sectioned longitudinally into equal halves. In the experimental group a thin layer of NSCH was applied whilst the control group had no medicament. After 1, 3 and 6 months, nanoindentation was used to assess dentine hardness and the modulus of elasticity. Scanning Electron Microscopy (SEM) was used to visualize the depth of penetration of NSCH into the dentinal tubules.
  
  
  RESULTS
  SEM images showed that there were no structural changes in the dentine slabs that had NSCH application after 1, 3 or even 6 months. However, penetration of NSCH into the dentine tubules was seen at both 3 and 6 months with a significant reduction in the hardness of dentine observed at 3 (p<0.02) and 6 months (p<0.01). The modulus of elasticity was significantly lower (p<0.01) at 6 months.
  
  
  CONCLUSIONS
  It appears that there is a significant reduction in the hardness of dentine with increasing periods of calcium hydroxide application. Prolonged application of NSCH could have a detrimental effect on dentine, making the dentine more prone to fracture.
authors.affiliation: Department of Paediatric Dentistry, Leeds Dental Institute, Leeds, LS2 9LU England. den4wat@yahoo.co.uk
authors.forename: W A
authors.initials: WA
authors.lastname: Twati
authors.forename: D J
authors.initials: DJ
authors.lastname: Wood
authors.forename: T W
authors.initials: TW
authors.lastname: Liskiewicz
authors.forename: N S
authors.initials: NS
authors.lastname: Willmott
authors.forename: M S
authors.initials: MS
authors.lastname: Duggal
mesh_terms: D000293:Adolescent; D002126:Calcium Hydroxide / Q000494:pharmacology*; D002648:Child; D003804:Dentin / Q000187:drug effects*; D003806:Dentin Permeability / Q000187:drug effects*; D055119:Elastic Modulus / Q000187:drug effects; D006244:Hardness / Q000187:drug effects; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010865:Pilot Projects; D012387:Root Canal Filling Materials / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D012387:Root Canal Filling Materials; D002126:Calcium Hydroxide