The effect of bone particle size on the histomorphometric and clinical outcomes following lateral ridge augmentation procedures. A randomized double blinded controlled trial

AUTHORS

Hussein S. Basma, Muhammad H.A. Saleh, Nico C. Geurs, Peng Li, Andrea Ravidà, Hom-Lay Wang, Ramzi V. Abou-Arraj

ABSTRACT

Background

The aim of this randomized clinical trial was to clinically and histologically compare the amount and quality of bone gained after lateral ridge augmentation (LRA) procedures performed using small (250-1000μm) versus large (1000-2000μm) particle size cortico-cancellous bone allografts at 6 months following surgical intervention.

Materials and Methods

22 patients, each presenting with ridge width less than 5mm were enrolled. Patients were randomly allocated to small (SP) and large particle (LP) size graft. The gain in ridge width at the level of the crest and 4mm apical to the crest was assessed via a standardized procedure before grafting and at time of implant placement, using a surgical caliper and a novel digital technique using cone beam computed tomography (CBCT). Six months following the procedure, trephine bone cores were taken from 19 augmented sites out of 17 patients (14/19 sites were in the posterior mandible) who completed the study for clinical, histologic and histomorphometric analysis.

Results

17 patients (19 sites) completed the study. LP size graft resulted in greater ridge width gain at the level of the crest (LP, 5.1 ± 1.7; SP, 3.7 ± 1.3 mm; p = 0.0642) and 4mm apical to the crest (LP, 5.9 ± 2.2; SP, 5.1 ± 1.8 mm; p = 0.4480) compared with the SP. No statistical significance for the bone density at the time of implant placement (p = 1.00) was found. Vital bone formation was more extensive in the SP compared with the LP 41.0 ± 10.1% vs 31.4 ± 14.8%, respectively (p = 0.05).

Conclusion

The results of the present article show a trend of higher ridge gain using LP during bone augmentation procedure. Future research with bigger sample size should confirm the results of the present article.

Cell and Tissue Response to Polyethylene Terephthalate Mesh Containing Bone Allograft in Vitro and in Vivo

AUTHORS

D. Joshua Cohen, Lisa Ferrara, Marcus B. Stone, Zvi Schwartz and Barbara D. Boyan

ABSTRACT

Background Extended polyethylene terephthalate mesh (PET, Dacron) can provide containment of compressed particulate allograft and autograft. This study assessed if PET mesh would interfere with osteoprogenitor cell migration from vertebral plates through particulate graft, and its effect on osteoblast differentiation or the quality of bone forming within fusing vertebra during vertebral interbody fusion.

Methods The impact of PET mesh on the biological response of normal human osteoblasts (NHOst cells) and bone marrow stromal cells (MSCs) to particulate bone graft was examined in vitro. Cells were cultured on rat bone particles +/− mesh; proliferation and osteoblast differentiation were assessed. The interface between the vertebral endplate, PET mesh, and newly formed bone within consolidated allograft contained by mesh was examined in a sheep model via microradiographs, histology, and mechanical testing.

Results Growth on bone particles stimulated proliferation and early differentiation of NHOst cells and MSCs, but delayed terminal differentiation. This was not negatively impacted by mesh. New bone formation in vivo was not prevented by use of a PET mesh graft containment device. Fusion was improved in sites containing allograft/demineralized bone matrix (DBM) versus autograft and was further enhanced when stabilized using pedicle screws. Only sites treated with allograft/DBM+screws exhibited greater percent bone ingrowth versus discectomy or autograft. These results were mirrored biomechanically.

Conclusions PET mesh does not negatively impact cell attachment to particulate bone graft, proliferation, or initial osteoblast differentiation. The results demonstrated that bone growth occurs from vertebral endplates into graft material within the PET mesh. This was enhanced by stabilization with pedicle screws leading to greater bone ingrowth and biomechanical stability across the fusion site.