In vivo comparison of a granular and putty form of a sintered and a non-sintered silica-enhanced hydroxyapatite bone substitute material

Abstract

Improved handling characteristics of bone substitute materials may facilitate surgical handling. However, the respective modifications should not alter the biological activity. For comparison of a granular and a putty form of two silicaenhanced bone substitute materials, in 30 rabbits, bilateral bone defects were created in the femoral condyle and randomly filled with (1) sintered, silica-enhanced (0.8 wt%) hydroxyapatite (ACg, n ¼ 15); (2) ACg plus resorbable polymer (ACp, n ¼ 15); (3) non-sintered silica-enhanced hydroxyapatite (hydroxyapatite/SiO 2 ratio:61:39 wt%; NBg, n ¼ 15); and (4) NBg plus matrix of resorbable polymer (NBp, n ¼ 15). After 4, 8, and 12 weeks, respectively, newformed bone, remaining bone substitute materials, and amount of soft tissue were quantified histomorphometrically. After four weeks, new-formed bone was increased for NBg/NBp in which NBp showed significantly less remaining bone substitute materials when compared to ACg. After two months, the highest amount of new-formed bone and the least remaining bone substitute materials were seen for NBg and NBp. ACp had less remaining bone substitute material when compared to ACg. In addition, amount of soft tissue was significantly enhanced in NBp when compared to ACg and NBg. After 12 weeks, NBp had significantly lower remaining bone substitute material when compared to ACg. Amount of soft tissue was significantly increased in NBp when compared to ACg and NBg. In accordance, based on an early increase of new-formed bone, a lower amount of remaining bone substitute material, and as well as a distinct degradation, superiority of the non-sintered bone substitute material to the sintered bone substitute material was seen. The effect of the resorbable polymer to each bone substitute material can be supposed to be rather marginal.

Improving material properties of a poloxamer P407 hydrogel‐based hydroxyapatite bone substitute material by adding silica—A comparative in vivo study

“…Previous studies have shown that non‐sintered BSM exhibits an increased formation of new bone compared with sintered BSM 34 . This might be explained by the higher percentage of pores facilitating the ingrowth of new bone and blood vessels 35,36 .…”

“…Previous studies have shown that non-sintered BSM exhibits an increased formation of new bone compared with sintered BSM. 34 This might be explained by the higher percentage of pores facilitating the ingrowth of new bone and blood vessels. 35,36 The BSM used in the present study is known to have a chiseled-ruffled, large surface with a mean pore size distribution of 330-530 μm representing the optimal pore size for osteoconduction.…”

“…This theory is supported by other studies lacking the ability to detect any poloxamer after 4 weeks in an in vivo rabbit model. 34 On the other hand, the P407 hydrogel might be dissolved by the histological processing of the sample before the histomorphometry analysis. Contrarily to the observed nondetection of the P407 hydrogel in the study at hand, others-using different histological processing methods-reported varying amounts of basophilic remnants of the poloxamer gel throughout the entire augmentation area after 14 weeks in a dog model 43 and even after 3 weeks postoperatively in a rabbit model.…”

Combination of an allogenic and a xenogenic bone substitute material with injectable platelet-rich fibrin – A comparative in vitro study

“…The main prerequisites for ideal BSM are both ease of its handling and application as well as biological characteristics close to autologous bone. 42 Considering that, allograft may be the BSM of choice, due to its unlimited availability, possibility of patient specific customization and its biocompatibility. Generally, ABSM has the potential to induce endochondral bone formation, that is feasible by incorporated BMPs and collagen type I, [43][44][45] although limited in comparison to autologous bone.…”

The efficacy of a nanosynthetic bone graft substitute as a bone graft extender in rabbit posterolateral fusion

“…A number of calcium phosphate-based synthetic bone graft substitutes have been developed in the last decade that build upon the traditional concepts of synthetic bone graft technology. These include the development of chemically modified calcium phosphates [11], incorporation of a submicron surface topography to the granules [1,3] and using nanoscale materials in manufacturing the bone graft [12]. The efficacy of such materials is typically evaluated by comparison to autograft in a pre-clinical model of posterolateral spinal fusion [5,6,[13][14][15], using the validated Boden model in rabbits that shows fusion rates with autograft that are similar to this in humans [16].…”