Guided bone regeneration using beta-tricalcium phosphate and leucocyte platelet-rich fibrin versus a novel biodegradable urethane composite in critical-size osseous defects in rabbit tibia: Histologic results of a pilot study

Background

Insufficient bone volume is a major problem in implant dentistry, which can be counteracted by using guided bone regeneration technique. Among the materials recently tested, synthetic polymers have been recommended as showing excellent biocompatibility and biodegradability.

Objective

The aim of this pilot study was to analyze and compare through means of histology the healing of the bone tissue in critical size osseous defects in New-Zealand rabbit tibiae after application of beta-tricalcium phosphate (β-TCP) alone, β-TCP combined with leucocyte platelet-rich fibrin (L-PRF) and an injectable experimental bone cement (EBC) represented by a dual-curable degradable synthetic polymer.

Methods

Two New-Zealand rabbits were used. Three standardized osseous defects of 5 mm diameter were created in each tibia. Each defect was filled with either β-TCP alone (control), β-TCP combined with L-PRF (test) or with EBC (test). The animals were sacrificed at 25 and 70 days; the tibia samples were removed, fixed in 10 % formaldehyde and stained with AZAN.

Results

While at 25 days β-TCP produced sparse bone formation, at 70 days mature bone formation was visible in all areas of the defect with minimum remaining graft particles; at 25 days, β-TCP combined with L-PRF produced broad areas of bone lamellae, while at 70 days bone tissue formation was limited; at both 25 and 70 days, the EBC was stable and not penetrated by bone cells, while a narrow band of connective tissue could be seen superjacent and inferior to it.

Conclusions

Among the tested biomaterials, β-TCP was capable of generating bone formation at both healing time-points, while the addition of L-PRF seemed to provide a synergistic effect only in the early phase of bone healing.