ObjectivesWe determined and structurally analyzed the reported effect of hydroxyapatite (HA) bone substitute on alveolar bone regeneration. To the best of our knowledge, no systematic reviews have previously reported the bone regenerative effect of the HA bone substitute.Materials and methodsA literature search was performed for articles published up to August 2015 using MEDLINE with the search terms “hydroxyapatite,” “bone regeneration,” and “alveolar bone” as well as their known synonyms. The inclusion criteria were set up for human trials with at least five patients. The literature search, eligible article selection, and data extraction were independently performed by two readers, and their agreement was reported by κ value.ResultsOf the 504 studies found using the MEDLINE literature search, 241 were included for further steps (inter-reader agreement, κ = 0.968). Abstract screening yielded 74 studies (κ = 0.910), with 42 completely fulfilling the inclusion criteria (κ = 0.864). In a final step, 42 studies were further analyzed, with 17 and 25 studies with and without statistical analysis, respectively. The 17 studies reporting similar outcome measures were compared using the calculated 95% confidence intervals. The effect of HA on ridge preservation could not be evaluated.ConclusionsThe use of the HA bone substitute interfered with the normal healing process, with significant differences found for sinus augmentation but not for periodontal bone defects. Thus, a bone substitute with optimal bone regenerative properties for alveolar ridge or socket preservation, sinus augmentation, and periodontal bony defect should be developed.

Calcium sulfate, also known as plaster of Paris (POP), is probably the oldest biomaterial used for bone grafting and considered to be a fast degradable material that allows complete resorption before the bone defect area is completely filled by new bone. The aim of this study was to investigate the possibility to combine POP with calcium carbonate in order to increase the the osteoconductivity of this material. Twenty four male Sprague Dawley rats, 5-months-old and weighing 300-350 g, were used in the study. Various treatment groups were created by the implantation of cylindrical samples of POP-100, POP-075 and POP-050 into the femoral condyles. After 1 and 4 weeks of implantation, rats were sacrificed and the implanted areas and the surrounding tissue were retrieved for histological analysis. The study was completed by an in vitro experiment, which included the soaking of the experimental materials into simulated body fluid. The results indicated that the composites were appropriate to be used as bone grafting material. The incorporation of CaCO3 into POP did decrease the degradation rate of the cements and induced faster bone formation, thus provides promising properties to this material.

Gypsum or calcium sulfate (CS) or plaster of Paris (POP) is considered as a fast degradable material that usually resorbs before the bone defect area is completely filled by new bone. In this study, the incorporation of CaCO3 hydrogel into POP in different compositions was proposed to enhance the bone biological activity of POP and to decrease its degradability. The mechanical and degradation properties of the various materials were characterized by in vitro analysis. Subsequently, the materials were inserted into cylindrically sized bone defects as created into the femoral condyle of rats and left in situ for 1, 4, and 8 weeks. Histological analysis of the retrieved specimens indicated that the addition of CaCO3 hydrogel into POP increased bone formation, angiogenesis and collagen density and resulted into faster bone formation and maturation. It was also confirmed that the degradation rate of the POP decreased by the addition of CaCO3 hydrogel. The in vivo findings did corroborate with the in vitro analysis. In conclusion, the incorporation of CaCO3 hydrogel provides a promising technology to improve the properties of POP, the oldest biomaterial used for bone grafting.

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The incorporation of CaCO hydrogel has been proven to enhance the bone biological activity of Plaster of Paris (POP) and to decrease its degradability. However, the installation of this bone substitute in a bone defect will still be associated with an inflammatory response. In this study, the influence of cinnamaldehyde as anti-inflammatory agent, was investigated. In addition, it is known that aldehyde chains of cinnamaldehyde may also act as crosslinking agent and function as a plastisizer to the CaCO hydrogel construct. Therefore, different concentrations of cinnamaldehyde were added to CaCO hydrogel and the effect on the diametral tensile strength, age swelling, gel fractination, cinnamaldehyde release, antimicrobial effect, and cell cytotoxycity were investigated. The incorporation of cinnamaldehyde was found to decrease the age swelling and degradation rate of CaCO hydrogel and to have no toxic effect to human gingival fibroblast cells. Moreover, the incorporation of cinnamaldehyde essential oil into the CaCO hydrogel was beneficial and acted as an antiinflammatory agent. Further research in vivo is warranted to determine the final favorable effect of cinnamaldehyde incorporated CaCO hydrogel in POP to provide a bone substitute. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 768-774, 2016.