Implantable biomaterials are increasingly important in the practice of modern medicine, including fixative, replacement, and regeneration therapies, for reconstruction of hard tissues in patients with pathologic osseous and dental conditions. A number of newly developed advanced biomaterials have been introduced as promising candidates for tissue reconstruction. Among these, zirconia-based biomaterials have gained attention as a biomaterial for hard tissue reconstruction due to superior mechanical properties and good chemical and biological compatibilities. This review summarizes the types of zirconia, advantages of zirconia-based biomaterials for hard tissue reconstruction including bone and dental tissues, responses of tissue and cells to zirconia, and surface modifications for enhanced bioactivity of zirconia. Current and future applications of zirconia-based biomaterials for bone and dental reconstruction, ie, medical implanted devices, dental prostheses, and biocompatible osteogenic scaffolds, are also discussed.
Scarring remains a serious complication of the wound healing process that can lead to the formation of excessive fibrous connective tissue in an organ or tissue leading to pain and loss of function. This process is mainly regulated by Transforming growth factor β1 (TGF-β1), which binds to receptors and induces its downstream mediator, Connective tissue growth factor (CTGF). The number of drugs targeting CTGF for treating scars has been on the rise in the past few years. The purpose of this article is to suggest the possibility of using cornea as a model for testing anti-CTGF therapies for scarring.
Heterotopic ossification (HO) is frequently reported following total joint replacement (TJR) surgery. Symptomatic HO may limit the range of motion, cause pain, and require surgical excision. Deciding an appropriate time for ectopic bone excision is based on clinical judgment, and a more well-defined link between clinical predictors and histological analysis is needed to minimize recurrence. A case series was performed with military healthcare system patients undergoing TJR, who required removal of periarticular ectopic bone. Patients were prescribed oxytetracycline to assess the mineral apposition rate (MAR; ie, bone growth rate) of HO, and excised specimens were analyzed using scanning electron microscopy and light microscopy. Two males and one female were enrolled in this study, with height of 69.0 ± 7.8 inches, weight of 237.7 ± 28.3 pounds, and age of 61 ± 7 years at the time of HO removal. Ectopic bone occurred in two cases following total knee arthroplasty and one total hip arthroplasty. Data indicated that MAR levels were 1.7 times higher than that reported previously for nonpathological human bone (1.7 ± 0.7 µm/day; range: 1.3–2.6 µm/day), and microscopic imaging confirmed that the osseous tissues were still actively remodeling at the time of surgical intervention. Further characterization is needed to optimize HO excision timing and to better understand this pathological bone disorder.
Hydroxyapatite (HA) is an essential element required for bone regeneration. Different forms of HA have been used for a long time. The essence of bone regeneration always revolves around the healthy underlying bone or it may be the surroundings that give enough strength. HA is well known for bone regeneration through conduction or by acting as a scaffold for filling of defects from ancient times, but emerging trends of osteoinductive property of HA are much promising for new bone regeneration. Emerging technology has made the dreams of clinicians to realize the use of HA in different forms for various regenerative purposes both in vivo and in vitro. The nanostructured calcium apatite plays an important role in the construction of calcified tissues. The nanostructured material has the ability to attach biological molecules such as proteins, which can be used as functional materials in many aspects, and the capability of synthesizing controlled structures of apatite to simulate the basic structure of bone and other calcified tissues. The process of regeneration requires a biomimetic and biocompatible nanostructured novel material. The nanostructured bioceramic particles are of interest in synthetic bone grafts and bone cements both injectable and controlled setting, so that such composites will reinforce the strength of bioceramics. Extensive research is being carried out for bone regeneration using nanotechnology. Artificial bone formation is not far from now. Nanotechnology has made many dreams come true. This paper gives comprehensive insights into the history and evolution with changing trends in the use of HA for various regenerative purposes.
Through mediation of integrin clustering, nanoscale surface structure of carbon nanotubes (CNTs) directly affects cell binding and subsequent behavior. The influence of morphological structures on proliferation, differentiation, and organization of focal adhesions and cytoskeleton of human mesenchymal stem cells (hMSCs) was studied. The following two surface morphologies were fabricated and examined: a random network multiwalled carbon nanotubes film (RNCNT) and a vertically aligned multiwalled carbon nanotube (VACNT) film. hMSCs adhered and spread earlier on both CNT surfaces than on control. A statistically significantly increased number of attached cells were observed on VACNT surfaces. No CNT substrate enhanced differentiation, but both maintained the differentiation property of hMSCs. VACNTs recruited vinculin from the cytoplasm for the formation of focal adhesion complexes earlier in comparison to RNCNT. There is still disparity on how nanostructures regulate the progression toward an osteoblastic phenotype. It is necessary to explore various architectures in order to understand how they initiate osteoinductive or proliferating signals.
