title: Structural, morphological, compositional, and mechanical changes of palatal implants after use: a retrieval analysis.
abstract: OBJECTIVE
  The aim of this study was to characterize the surface, elemental, and mechanical alterations of orthodontic palatal implants after intraoral aging.
  
  
  METHODS
  Nineteen consecutively retrieved implants (RET) after orthodontic treatment and three unused implants used as control (CON) were included in this study. Both groups were characterized non-destructively by Stereomicroscopy, Optical Profilometry (Sa, Sq, Sz, Sc), and SEM/EDX analysis and then destructively after metallogaphic preparation employing instrumented indentation testing (HM, EIT, ηIT, and HV) and SEM/EDX at bone-implant interface.
  
  
  RESULTS
  All retrieved implants showed a loss of gloss with the formation of bone-like formation on the majority of them. However, no differences in surface roughness parameters were identified between macroscopically intact and retrieved regions of implants. The elements precipitated on the surface were O, C, Ca, and P while traces of Na, K, Al, S, Cl, and Mg were also identified. The surface of control sample is characterized by small pits while only Ti and Al traces were identified by EDX analysis. The presence of all the aforementioned elements apart from Ti and Al on the retrieved implants' surface should be appended to the contact of implant with bone and biological fluids while Interfacial analysis revealed a well-formed bone-implant interface. However, no significant differences were found for all mechanical properties tested between RET and CON groups.
  
  
  CONCLUSIONS
  The results of this study indicate that retrieved palatal implant surface has undergone morphological and elemental alterations probably associated with the osseointegration process during service. Insertion and functional loading did not affect the mechanical properties of implants tested.
authors.affiliation: Clinic of Orthodontics and Paediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Marc
authors.initials: M
authors.lastname: Schätzle
authors.affiliation: Department of Dental Biomaterials, School of Dentistry, National and Kapodistrian, University of Athens, Athens, Greece.
authors.forename: Spiros
authors.initials: S
authors.lastname: Zinelis
authors.affiliation: Clinic of Orthodontics and Paediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Goran
authors.initials: G
authors.lastname: Markic
authors.affiliation: Department of Dental Biomaterials, School of Dentistry, National and Kapodistrian, University of Athens, Athens, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Eliades
authors.affiliation: Clinic of Orthodontics and Paediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Theodore
authors.initials: T
authors.lastname: Eliades
mesh_terms: D000069343:Bone-Implant Interface; D015921:Dental Implants; D006801:Humans; D008422:Materials Testing / Q000379:methods; D008855:Microscopy, Electron, Scanning; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016382:Orthodontic Appliance Design; D016348:Osseointegration; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D015921:Dental Implants; D014025:Titanium