title: Relation between the stability of dental implants and two biological markers during the healing period: a prospective clinical study.
abstract: OBJECTIVE
  The purposes of this study were to examine the correlation between the stability of dental implants and bone formation markers during the healing period and to monitor the stability of dental implants using the resonance frequency analysis (RFA) method. The null hypothesis of the study is no correlation between the stability of dental implant and bone formation markers.
  
  
  METHODS
  The study is a prospective clinical study during the 3-month healing period of implant. At implant placement (PW Plus, Nakhon Pathom, Thailand) and after 1, 2, 3, 4, 6, 8, 10, and 12 weeks, RFA assessments were performed and gingival (GCF)/peri-implant crevicular fluids (PICF) were collected from ten patients. The level of osteocalcin (OC) was measured by using ELISA kits, and the level of alkaline phosphatase (ALP) activity was measured by colorimetric analysis. Repeated measures analysis of variance, the Friedman test, the Mann-Whitney U test, and the Pearson correlation were performed for data analysis.
  
  
  RESULTS
  There was a statistical decrease in the mean implant stability quotient (ISQ) values between 1 and 3 weeks (P < 0.05). The ISQ values recovered to the initial values at 4 weeks. There was no statistical difference in the ALP level at each measurement, while there was a statistical increase in the OC level at 6, 8, 10, and 12 weeks when compared with 1 week (P < 0.05). There was a significant correlation between ALP levels and ISQ values (r = 0.226, P < 0.05). There was a statistically significant correlation between OC levels and ISQ values at 1-12 weeks (r = 0.245, P < 0.05).
  
  
  CONCLUSIONS
  The ISQ values were weakly correlated with both ALP and OC. The three-thread-design implant showed a high stability through healing period.
authors.affiliation: Center of Excellence for Dental Implantology, Faculty of Dentistry, Chiang Mai University, Suthep sub-district, A. Muang, Chiang Mai, 50200, Thailand.
authors.forename: Choknapa
authors.initials: C
authors.lastname: Tirachaimongkol
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Thailand Excellence Center for Tissue Engineering and Stem Cells, Chiang Mai, Thailand.
authors.forename: Peraphan
authors.initials: P
authors.lastname: Pothacharoen
authors.affiliation: Department of Oral Medicine, Dental Radiology and Oral Surgery, Center for Dental, Oral and Maxillary Medicine, Charite - University of Medicine, Berlin, Germany.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Reichart
authors.affiliation: Center of Excellence for Dental Implantology, Faculty of Dentistry, Chiang Mai University, Suthep sub-district, A. Muang, Chiang Mai, 50200, Thailand. pathaweek@gmail.com.
authors.forename: Pathawee
authors.identifier: http://orcid.org/0000-0002-5994-4482
authors.initials: P
authors.lastname: Khongkhunthian
keywords: Biomarker; Implant stability quotient; Osseointegration; Resonance frequency analysis