title: Influence of root conditioning prior to EMD application on periodontal ligament cells of extracted teeth.
abstract: BACKGROUND
  Root conditioning prior to the application of Enamel Matrix Derivative (EMD) on the root surface was suggested for treatment of replanted avulsed teeth. However, some studies do not support the use of root conditioning. The purpose of this study was to investigate the effects of root conditioning on cell proliferation and Alkaline Phosphatase (ALP) activity on application of EMD in vitro.
  
  
  METHODS
  Thirty incisors of five beagle dogs were used. The roots were hemisectioned axially and the periodontal ligament and cementum were removed from the coronal half of the roots. The specimens were treated with or without root conditioning (24% EDTA for 2 minutes or 36% ortho-phosphoric acid for 60 seconds) and EMD were or was not applied. Then all specimens were observed using SEM or cultured for 4 weeks. After culture, the cell migration and alkaline phosphatase activity of migrated and proliferated cells on the root planed surface from the remaining periodontal ligament was histometrically observed.
  
  
  RESULTS
  The cell population in EMD-applied groups was significantly higher than that without EMD application groups. There was no significant difference among the two root conditioning protocols and EMD alone. ALP activity of migrated and proliferated cells in the EMD in combination with EDTA group was significantly higher than the other groups. However, 36% ortho-phosphoric acid group showed the lowest value.
  
  
  CONCLUSIONS
  The findings in this study showed that EMD in combination with 24% EDTA showed additional benefit in terms of population of cells expressed APL activity on the root surface compared with application of EMD alone.
authors.forename: Akira
authors.initials: A
authors.lastname: Saito
authors.affiliation: Department of Periodontology and Endodontology, Division of Oral Health Science, Hokkaido University Graduate School of Dental Medicine Kita-13, Nishi-7, Kita-ku, Sapporo 060-8586, Japan, Tel: +81 11 706 4266; Fax: +81 11 706 4334; e-mail: water@den.hokudai.ac.jp.
authors.forename: Emiko
authors.initials: E
authors.lastname: Saito