Titanium has been widely used for dental implants, and in particular, roughened titanium surfaces have provided a means for increasing bone apposition and strengthening the implant-to-bone interface. Finding a way to further increase osseointegration is important because there is a significant clinical benefit to patients if a stable anchor can be established instead of anchoring orthodontic hardware to the molars. In this study, the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) on the ability of temporary anchorage devices (TADs) to osseointegrate was investigated. The temporary anchorage devices (TADs) used in this study were manufactured from commercially pure titanium and divided into 2 types of treatments: (1) sandblasted and acid-etched (i.e. the control) and (2) sandblasted and acid-etched treated with Medtronic INFUSE® Bone Graft (recombinant human bone morphogenetic protein-2 placed on an absorbable collagen sponge). The implants were placed on the cranial bones of 10 adult male Sprague-Dawley rats. The rats were euthanized by carbon dioxide asphyxiation 6 weeks following surgery for histological examination and biomechanical testing. The results from visual inspection and biomechanical testing showed that the sandblasted and acid-etched TADs treated with rhBMP-2 promoted better osseointegration than TADs that were only sandblasted and acid-etched. Specifically, surface modified TADs treated with rhBMP-2 on bottom showed an increased surface coverage by bone and an increase in the adhesion strength at the TAD-to-bone interface.

Over the past 5 years, the use of titanium implants as temporary anchorage devices (TADs) has become an important tool in clinical orthodontic practices. The use of TADs have provided orthodontists a way of moving teeth against fixed objects rather than against the surrounding teeth, which tend to counteract desired motion. At present, viable attachment of TADs involves direct insertion through gingival tissue and piercing of the bone. Surface modifications such as sandblasted and acid-etched treatment or bone morphogenetic protein surface treatment, however, can be applied to the TADs to promote enhanced osseointegration, thereby allowing the TADs to serve as stable anchors while avoiding bone puncture. In this study, a comparison was made between sandblasted/acid-etched TADs and sandblasted/acid-etched/recombinant human bone morphogenetic protein-2 (rhBMP-2) treated TADs to determine whether rhBMP-2 promotes enhanced osseointegration. A total of 10 rats (4 controls and 6 treated with rhBMP-2) were used in the study, with 1 TAD placed on the skull of each rat. At the end of 6 weeks, the animals were euthanized by carbon dioxide asphyxiation, and bone blocks, each containing a TAD, were prepared for histological examination and biomechanical characterization. The results of this study showed that TADs treated with rhBMP-2 had greater bone formation at the bone-implant interface and an increase in total implant stability.