Effect of guided bone regeneration on bone quality surrounding dental implants

Abstract

Bone quality as well as its quantity at the implant interface is responsible for determining stability of the implant system. The objective of this study is to examine the nanoindentation based elastic modulus (E) at different bone regions adjacent to titanium dental implants with guided bone regeneration (GBR) treated with DBM and BMP-2 during different post-implantation periods. Six adult male beagle dogs were used to create circumferential defects with buccal bone removal at each implantation site of mandibles. The implant systems were randomly assigned to only GBR (control), GBR with demineralized bone matrix (DBM), and GBR with DBM + recombinant human bone morphogenetic protein-2 (rhBMP-2) (BMP) groups. Three animals were sacrificed at each 4 and 8 weeks of post-implantation healing periods. Following buccolingual dissection, the E values were assessed at the defects (Defect), interfacial bone tissue adjacent to the implant (Interface), and pre-existing bone tissue away from the implant (Pre-existing). The E values of BMP group had significantly higher than control and DBM groups for interface and defect regions at 4 weeks of post-implantation period and for the defect region at 8 weeks (p < 0.043). DBM group had higher E values than control group only for the defect region at 4 weeks (p < 0.001). The current results indicate that treatment of rhBMP-2 with GBR accelerates bone tissue mineralization for longer healing period because the GBR likely facilitates a microenvironment to provide more metabolites with open space of the defect region surrounding the implant.

Keywords: Bone quality; Dental implant; Guided bone regeneration; Nanoindentation; rhBMP-2.

Fig. 1

The implant placement procedure for a) creation of the defects using a trephine drill, b) buccal dehiscence defects, c) circumferential and d) buccal defect space following implant placement, e) filling DBM gel or rhBMP-2+DBM gel in the defect, and f) BioGuide membrane placement (Han, 2012).

Fig. 2

a) Representative histological image of the indent locations as 1) defect area, 2) interfacial bone area, and 3) pre-existing bone area with magnified image of new bone formation using fluorescence bone labeling (green bands: oxytetracycline HCl, red bands: xylenol orange) and b) a typical scanning electron microscopic image of indentation site and load-displacement curve of nanoindentation.

Fig. 3

Effects of treatment on regional variation of nanoindentation modulus (E) at (a) 4 weeks and (b) 8 weeks of post-implantation periods. *; p<0.045, **; p<0.001.