title: Selective laser melting of titanium alloy enables osseointegration of porous multi-rooted implants in a rabbit model.
abstract: BACKGROUND
  Osseointegration refers to the direct connection between living bone and the surface of a load-bearing artificial implant. Porous implants with well-controlled porosity and pore size can enhance osseointegration. However, until recently implants were produced by machining solid core titanium rods. The aim of this study was to develop a multi-rooted dental implant (MRI) with a connected porous surface structure to facilitate osseointegration.
  
  
  METHODS
  MRIs manufactured by selective laser melting (SLM) and commercial implants with resorbable blasting media (RBM)-treated surfaces were inserted into the hind limbs of New Zealand white rabbits. Osseointegration was evaluated periodically over 12 weeks by micro-computerized tomography (CT) scanning, histological analysis, mechanical push-out tests, and torque tests.
  
  
  RESULTS
  Bone volume densities were consistently higher in the MRI group than in the RBM group throughout the study period, ultimately resulting in a peak value of 48.41 % for the MRI group. Histological analysis revealed denser surrounding bone growth in the MRIs; after 4 and 8 weeks, bone tissue had grown into the pore structures and root bifurcation areas, respectively. Biomechanics tests indicated binding of the porous MRIs to the neobone tissues, as push-out forces strengthened from 294.7 to 446.5 N and maximum mean torque forces improved from 81.15 to 289.57 N (MRI), versus 34.79 to 87.8 N in the RBM group.
  
  
  CONCLUSIONS
  MRIs manufactured by SLM possess a connected porous surface structure that improves the osteogenic characteristics of the implant surface.
authors.affiliation: Key Laboratory of E&M, Ministry of Education & Zhejiang Province, Zhejiang University of Technology, Hangzhou, Zhe Jiang, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Peng
authors.affiliation: Key Laboratory of E&M, Ministry of Education & Zhejiang Province, Zhejiang University of Technology, Hangzhou, Zhe Jiang, People's Republic of China.
authors.forename: Liangwei
authors.initials: L
authors.lastname: Xu
authors.affiliation: Key Laboratory of E&M, Ministry of Education & Zhejiang Province, Zhejiang University of Technology, Hangzhou, Zhe Jiang, People's Republic of China.
authors.forename: Jia
authors.initials: J
authors.lastname: You
authors.affiliation: Department of Stomatology, Zhejiang University of Huzhou Hospital, Huzhou, Zhe Jiang, People's Republic of China. fanglh1212@126.com.
authors.forename: Lihua
authors.initials: L
authors.lastname: Fang
authors.affiliation: Department of Stomatology, Zhejiang University of Huzhou Hospital, Huzhou, Zhe Jiang, People's Republic of China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D000497:Alloys / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000494:pharmacology*; D001696:Biomechanical Phenomena; D015921:Dental Implants; D005260:Female; D007834:Lasers; D008297:Male; D008422:Materials Testing; D016348:Osseointegration / Q000187:drug effects*; D044367:Phase Transition; D016062:Porosity; D011817:Rabbits; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D019415:Torque; D055114:X-Ray Microtomography
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D015921:Dental Implants; D014025:Titanium
keywords: Biomechanics; Implant design; Multi-rooted implant; Osseointegration; Titanium (alloys)