title: The effect of axial and oblique loading on the micromovement of dental implants.
abstract: OBJECTIVE
  To quantify implant displacement upon axial and oblique force application and compare the effects of bone quality using an in vitro experimental setup.
  
  
  METHODS
  One hundred ninety-two implants were inserted into artificial bone block specimens using a drill guide. Ninety-six implants were placed in soft cancellous bone and loaded in 10-N increments up to 80 N in axial and oblique (30-degree angle) directions (n = 48 in each group). The other 96 implants were inserted in dense artificial bone and loaded in axial and oblique directions in the same force increments. Three-dimensional displacement data were recorded for all implants using a noncontact optical image correlation technique based on photogrammetric principles, and the absolute displacement vector was calculated.
  
  
  RESULTS
  There were significant differences in the absolute implant displacement in the different bone densities over all load increments. Implant displacement was significantly higher in soft cancellous bone than in dense bone. Axial and oblique loading revealed significant differences in implant displacement in the cancellous specimens, whereas oblique loading showed increased displacement (339 ± 47 Μm at 80 N) compared to axial loading (266 ± 39 Μm at 80 N). However, axial and oblique loading showed no significant differences over all load increments when implants were inserted in dense specimens (absolute displacement with an 80-N load: 147 ± 10 Μm axial and 126 ± 17 Μm oblique).
  
  
  CONCLUSIONS
  Bone density influenced implant displacement. The loading character (axial versus oblique) significantly influenced implant displacement in soft cancellous bone block specimens only. However, the limitation of the measured displacement values to an in vitro application that did not represent the complexity of vital bone has to be considered.
authors.affiliation: Dental Clinic 2, Department of Prosthodontics, University Clinic Erlangen, Germany. matthias.goellner@uk-erlangen.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Goellner
authors.forename: Johannes
authors.initials: J
authors.lastname: Schmitt
authors.forename: Matthias
authors.initials: M
authors.lastname: Karl
authors.forename: Manfred
authors.initials: M
authors.lastname: Wichmann
authors.forename: Stefan
authors.initials: S
authors.lastname: Holst
mesh_terms: D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology*; D018786:Bone Substitutes / Q000737:chemistry; D001842:Bone and Bones / Q000502:physiology; D000044:Dental Abutments; D015921:Dental Implants; D012994:Dental Soldering; D003799:Dental Stress Analysis / Q000295:instrumentation; D055119:Elastic Modulus; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional / Q000379:methods; D008422:Materials Testing; D009068:Movement; D010780:Photogrammetry; D011140:Polyurethanes / Q000737:chemistry; D013314:Stress, Mechanical
chemical_list: D018786:Bone Substitutes; D015921:Dental Implants; D011140:Polyurethanes