Bone repair induced by different bone graft substitutes in critical-sized defects in rat calvaria

Abstract

Introduction The use of bone substitutes in grafting procedures as an alternative of the use of autogenous bone graft has been indicated, however, the direct comparison between these biomaterials has been little explored. Objective To evaluate the effect of different osteoconductive bone substitutes on the bone repair in critical-sized defects (CSDs) in rat calvaria. Material and method One CSD with an 8 mm diameter was made in each of the 40 rats used in this study. The animals were randomly allocated into 5 groups (n=8), according to the type of bone substitute used to fill the CSD: COA (Coagulum); AUT (autogenous bone); DBB (deproteinized bovine bone graft); HA/TCP (biphasic ceramic composed of hydroxyapatite and β-phosphate tricalcium); and TCP (β-phosphate tricalcium). A microtomographic analysis was performed to evaluate the remaining defect linear length (DLL) of the CSD and the volume of the mineralized tissues (MT) within the CSD at 3, 7, 15 and 30 days after the surgical procedure. In addition, a histometric analysis was performed to evaluate the composition of the repaired bone tissue (% Bone and % Biomaterial) at the 30-day period. Result It was shown that the COA had the lowest DLL and MT within the CSD. In addition, the COA presented the highest % of bone in CSD. The DBB had a higher MT and a higher % of bone substitute particles in the CSD than the AUT and TCP groups. The DBB and AUT groups presented higher % of bone in the CSD than the TCP group. Conclusion The use of the DBB promoted a better pattern of bone volume gain and formation compared to TCP and HA / TCP but was biologically inferior to the AUT.

Polyurethane derived from castor oil monoacylglyceride (Ricinus communis) for bone defects reconstruction: characterization and in vivo testing

“…1d), at 2262 cm −1 , is not found in the CPU spectrum (Fig. 1e), confirming the total reaction between HDI and MAG [17,18,20].…”

“…In the TG curve of castor oil polyurethane (PU), thermal stability around 125°C, with a reduction in the initial sample mass around 60°C, observed in the DTG, probably resulting from the physical desorption of volatile components [15][16][17][18][19][20][21][22][23]. Moura-Neto et al [15] state that because of their structural`characteristics, polyurethanes decompose in two or three stages; the first stage is related to the breakdown of the isocyanate and alcohol bond; the second is due to the decomposition of the polyol, and the third is because of the elimination of CO2.…”

“…This research has been approved by the local Animal Use Ethics Committee (CEUA), protocol nº 00850/2016. The procedures performed in this study have followed the ethical principles established by the National Council for the Control of Animal Experimentation (CONCEA) and the National Institutes of Health guide (NIH) [19,20].…”

“…The animals were anesthetized with xylazine (10 mg/kg) (0.2% xylazine hydrochloride -Virbaxyl®) [17,19]. After trichotomy of the surgical area, a craniocaudal incision was made in the midline, exposing the calvaria where a 6 mm diameter defect was made in the central region, with the aid of a trephine drill (Harte Precision Grip®) and low -rotation, under constant irrigation [20]. The defects were filled with polyurethanes, according to the group to which each animal belonged.…”

“…The fact that the bonds cause an orderly arrangement of atoms or molecules with regular repetition in space can explain this semi-crystallinity. The molecular chains are densely packed in an ordered and parallel configuration, which justifies that the addition of HDI to castor oil leads to the formation of urethane groups through bonds between HDI and hydroxyls (-OH) [16][17][18]20].…”