Selective laser melting of titanium alloy enables osseointegration of porous multi-rooted implants in a rabbit model

• Published in: Biomedical engineering online Vol. 15; no. 1; p. 85
• Main Authors: Peng, Wei, Xu, Liangwei, You, Jia, Fang, Lihua, Zhang, Qing
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 21.07.2016; BioMed Central
• Subjects: Alloys - chemistry; Analysis; Animals; Biocompatible Materials - chemistry; Biocompatible Materials - pharmacology; Biomechanical Phenomena; Dental Implants; Female; Implant dentures; Lasers; Male; Materials; Materials Testing; Osseointegration - drug effects; Phase Transition; Porosity; Rabbits; Surface Properties; Titanium - chemistry; Titanium alloys; Torque; X-Ray Microtomography; Biomechanics; Osseointegration; Titanium (alloys); Multi-rooted implant; Implant design
• ISSN: 1475-925X; 1475-925X
• DOI: 10.1186/s12938-016-0207-9

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. 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. 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. MRIs manufactured by SLM possess a connected porous surface structure that improves the osteogenic characteristics of the implant surface.