Effects of static magnetic fields on bone regeneration of implants in the rabbit: micro‐CT, histologic, microarray, and real‐time PCR analyses

Abstract Objectives The aim of this study was to investigate the effects of static magnetic fields ( SMF s) on bone regeneration around titanium implants by μ CT , histologic analysis, microarrays, and quantitative real‐time PCR ( qRT ‐ PCR ). Materials and methods Neodymium magnets provided the source of SMF s, the specimens were grade 5 titanium implants, and the animals were twenty‐seven adult male New Zealand white rabbits. These implants were divided into six groups according to the presence of a magnet and predetermined healing period (1, 4, and 8 weeks). Each group comprised six specimens for μ CT ( n = 6) and histologic examination, and three specimens ( n = 3) for microarrays and qRT ‐ PCR , yielding a total of 54 specimens. Results The μ CT data showed that SMF s increased bone volume fraction (bone volume/total volume, BV / TV ), trabecular number (Tb.N), and trabecular thickness (Tb.Th). Histologic observation indicated that SMF s promoted new bone formation and direct bony contact with implants. Microarray analysis identified 293 genes upregulated (>twofold) in response to SMF s. The upregulated genes included extracellular matrix ( ECM )‐related genes ( COL 10A1, COL 9A1, and COL 12A1) and growth factor ( GF )‐related genes ( CTGF and PDGFD ), and the upregulation was confirmed by qRT ‐ PCR . Gene Ontology ( GO ) and pathway analysis revealed the involvement of the mitogen‐activated protein kinase ( MAPK ), Wnt, and PPAR ‐gamma signaling pathways in implant healing. Conclusions μ CT , histology, microarrays, and real‐time PCR indicate that SMF s could be an effective approach to improving bone regeneration around dental implants.