Abstract
Artificial bone graftingis the subject of intensive investigation for craniofacial reconstruction. Among the syntheticcandi date materials, those incorporating Calcium Phosphates (CaP) have gained popularity, due to their osteoinductive properties. Despite many quantitative studies on the degradation rates of CaP biomaterials in vitro, there is lack of quantitative studies in relation to bone remodelling kinetics in vivo. In this investigation, we tested implants of degradable CaP/chitosan-based biomaterial in a rat calvaria model of critical-sized defects. We observed remarkable acceleration of bone growth in the initial stages (~0.8 g/day), which was markedly higher than normal bone growth rates (~0.1 g/day) in implant-free controls. The implanted CaP-based biomaterial significantly enhanced bone formation, with woven bone seen as early as 20 days and lamellar bone at 40 and 60 days post-implantation. However the mineralisation of cortical bone was delayed, due to the overly rapid degradation of the biomaterial: This therapeutically important issue has never been identified before to our best knowledge. A theoretical analysis revealed that during degradation CaP can be rapidly released from the new bone matrix. Hence, while the degradable CaP biomaterial was found to be highly osteoconductive in vivo, future modifications would seek to optimize degradation efficiency for more sustained release of mineral ions, to enhance bone mineralisation at later stages of the healing process after implantation.
Highlights
The loss of teeth and supportive tissues in the jawbone often causes severe bone resorption, which hinders the healing process for dental implants, as well as recovery of physiological function and cosmetic appearance (Vignoletti et al, 2012)
Cellular toxicity was visible in the cultures containing extracts of Calcium Phosphates (CaP)-chitosan pastes of pH 6.8 and 7.2 (Fig. 2c and d), while the media containing the extracts of the pastes of pH 7.5 and 7.8 were found to support proliferation of MG63 cells (Fig. 2e and f)
Histological examination (Goldner’s Messon trichrome) revealed that the control defects remained empty, with little new bone formed up to 40 days post-implantation and the amount of new bone was considerable only in the samples of the 60-day treatment group (∼20 Ar. % of the defects) (Fig. 4). These results are in agreement with previous work on bilateral calvarial defects of 5 mm diameter, which reported that the area percentage of new bone formed in untreated control defects was approximately 20 and 23% at 2 and 3 months, respectively (Vajgel et al, 2013)
Summary
The loss of teeth and supportive tissues in the jawbone often causes severe bone resorption, which hinders the healing process for dental implants, as well as recovery of physiological function (e.g., chewing, speech) and cosmetic appearance (Vignoletti et al, 2012). Artificial bone grafts have been investigated using various synthetic materials, including Hydroxyapatite (HA), Calcium Phosphates (CaP), polyesters, chitosan and their composites (Chen et al, 2012). Among these biomaterials, those containing CaP have been extensively tested (Bohner et al, 2012; Chai et al, 2012) because of their osteoinductive properties (Geffre et al, 2010; Thormann et al, 2013). It has been reported that particle sizes ranging from 80 to 300 μm in diameter
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: American Journal of Biochemistry and Biotechnology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
