title: A Comparison of the Mechanical Measures Used for Assessing Orthodontic Mini-Implant Stability.
abstract: OBJECTIVE
  Mechanical loosening remains a common complication associated with mini-implant failure. The purpose of this study was to compare common mechanical measures of mini-implant stability to determine their association and reliability.
  
  
  METHODS
  Ninety self-drilling orthodontic mini-implants from 6 manufacturers were inserted into artificial bone blocks. Insertion torques (ITs) and Periotest values (PVs) were measured. Subsequently, mini-implants underwent pull-out testing for measures of pull-out load (POL) and screw displacement (ScrD). Stability measurements were compared using one-way ANOVA, associations among them were assessed using correlation analyses, and reliability was evaluated using coefficients of variation (COVs).
  
  
  RESULTS
  Variations in stability of mini-implants were found, specific to the mechanical measure used for assessment (P < 0.05). The strongest correlations were found between IT and PV (r = -0.68) and between IT and POL (r = 0.66). Overall, PV showed the greatest variability (COV: 11%-100%) compared with IT (≤11%), POL (≤4%), and ScrD (≤19%).
  
  
  CONCLUSIONS
  IT, PV, and POLs only agreed moderately in their assessment of mini-implant stability, and Periotest showed the least reliability in predicting mini-implant stability. As such, independent and interchangeable use of these stability measures should be avoided.
authors.affiliation: *Postdoctoral Fellow, Division of Graduate Orthodontics, Schulich School of Medicine & Dentistry; Bone and Joint Institute; Western University, London, Ontario, Canada. †Distinguished University Professor, Division of Graduate Orthodontics, Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry; Bone and Joint Institute; Western University, London, Ontario, Canada. ‡Professor, Division of Graduate Orthodontics, Schulich School of Medicine & Dentistry; Department of Chemical and Biochemical Engineering, Faculty of Engineering; Bone and Joint Institute; Western University, London, Ontario, Canada. §Assistant Professor, Division of Graduate Orthodontics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada.
authors.forename: Yara K
authors.initials: YK
authors.lastname: Hosein
authors.forename: S Jeffrey
authors.initials: SJ
authors.lastname: Dixon
authors.forename: Amin S
authors.initials: AS
authors.lastname: Rizkalla
authors.forename: Ali
authors.initials: A
authors.lastname: Tassi
mesh_terms: D015921:Dental Implants; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000379:methods*; D006801:Humans; D052280:Orthodontic Anchorage Procedures / Q000379:methods
chemical_list: D015921:Dental Implants