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.

Both EHA and SHA graft materials are equally efficient in early bone regeneration. Within the limitations of this study the EHA showed promising results. Which indicates the eggshell waste-bio mineral is worthwhile raw material for the production of HA and is a Go Green procedure. Eggshell-derived hydroxyapatite is economic, compared with SHA.

Background Use of various bone graft substitutes are advised to prevent bone loss, periodontal problems, and enhance bone formation after surgical removal of the mandibular third molar. Choice of graft substitute depends on biological properties and the cost of the material. So, a preliminary study was planned to evaluate and compare the effectiveness of eggshell-derived nano-hydroxyapatite as an emerging graft substitute for the enhancement of bone regeneration. Materials and methods Twelve patients (out of 20 enrolled) were finally assessed for bone healing after surgical removal of bilateral mandibular third molars in a split-mouth randomized controlled clinical study. All of them were assessed and compared at baseline, first, third, and sixth month. Clinically wound healing and probing depth were assessed. Radiographically the changes in density, bone formation characteristics, and bone level were evaluated. The observers were blinded for the surgical procedure and follow-up duration. The study protocol was approved by Institutional Ethics Committee and registered with National clinical trial registry. Results Wound healing was uneventful in all 24 extraction sites of 12 patients. Trabecular bone pattern with increased bone density was observed indicating complete bone healing in the graft group at third month. Probing depth was gradually decreased over a follow-up period and remained within normal limits during the third-month follow-up. These changes in the graft group were significant compared to the control group. The grafting with eggshell-derived nano-hydroxyapatite showed better bone regeneration properties without any infection or undue reactions. Conclusion Eggshell-derived nano-hydroxyapatite showed enhancement of bone regeneration compared to the control group. Grafting maintained bone height and prevented periodontal problem emergence. Eggshell-derived nano-hydroxyapatite is a safe synthetic graft substitute because it is derived from eggshell without any diseases transfer risks, unlike allografts. The process of preparation is environment-friendly. The beneficial effects of eggshell-derived nano-hydroxyapatite may be extrapolated to develop an ideal economic graft substitute.

Our result supports the notion that MVDS is the treatment of choice for patients with trigeminal neuralgia. Pure MVDS can offer long-term cure rate of more than 98% of success for neuralgia in the presence of clear-cut and marked vascular compression at surgery.