Synthetic hydroxyapatite (HA) is a biocompatible, nontoxic, slowly resorbing, osteoconductive, osteophillic material, hydrophilic in nature, and has a high compressive and low tensile and shear strength. It has a close structural and chemical resemblance to bone mineral, but not identical.

Bioactive glass ceramics from the SiO2, CaO P2O5 family can develop a chemical bond with  living hard tissues though the development of a surface layer of carbonated hydroxyapatite. When these materials are exposed to tissue fluid, bioactive glasses are covered by silica rich gel  on top of which calcium phosphate rich layer is formed. The calcium phosphate rich layer promotes absorption and concentration of osteoblast cells to form an extra cellular matrix and mineralization.

Is Hydroxyapatite Bioactive Glass (HA-BG) Composite Bone Graft materials superior than Bioactive Glass Bone Substitute materials?

HABG Composite Bone Graft materials have an added advantage as they contain HA particles that act as a scaffold, encircling which osteoid could get deposited, resulting in early increase in strength of the newly forming bone. Bioactive glass containing graft particles may have an effective role in the treatment of periapical defects as compared to Hydroxyapatite.

Yes. BioGraft Synthetic Hydroxyapatite material has the property of ingrowth of fibrovascular tissue and osteo conductivity and thus can be used for correction of facial skeletal and soft tissue defects. BioGraft Synthetic Hydroxyapatite materials are bio-compatible, non-allegenic, non-toxic and qualitatively superior to the imported Hydroxyapatite.

Due to increased awareness, more and more surgeries for correction of facial abnormalities are being done. In India incidence of live birth with craniofacial clefts alone is in several thousands per year. Patients with facial skeletal and soft tissue defects due to acquired factors are much more. Synthetic Hydroxyapatite Bone Graft material is a useful alternative where the donor area is limited and/or donor area morbidity is unwanted. This material is affordable and within the reach of poor patients also.

BioGraft Synthetic Hydroxyapatite material, available both in Granules and Pre-forms, can be used for treatment of following facial deformities.

• Congenital facial and craniofacial clefts.
• Hemefacial microsomia
• Post traumatic facial skeletal defect.
• Benign facial skeletal neoplasm.
• Aesthetically unacceptable facial skeletal defect like midface retrussion, microgenia, micrgnathia.
• Correction of soft tissue defect.
  

Operations are performed under general anesthesia. Target bone is exposes property and its surface is made raw with the help of periostium elevator on which BioGraft Synthetic Hydroxyapatite material is applied. After irrigation with normal saline, the soft tissue pocket is closed meticulously. Post operatively the patients are kept under antibiotic coverage for 5 to 7 days. The common complications are hematoma and facial edema which subside during next 5 to 7 days. In some cases, edema last for about 3 weeks. It depends on the amount of soft tissue dissection. Infection may occur at the graft site from time to time, which subside with systemic application of antibiotics and dressing. As the graft becomes vascularised, the infection passes away. Average use of analgesics is much less as there is no donor site morbidity.

Post operatively nearly upto 3-4 weeks, grafted site remain tender and there are palpable crepitus. Thereafter, grafted area become firm in consistency and gradually tenderness passes away. At about 6 to 7 months the area becomes hard and clinical evidence of bone formation may be appreciated by radiograph but best by 3D CT.

Dental implant placement in the posterior maxillary region is frequently hampered by atrophic ridges resulting from bone resorption which could either be following tooth removal or from the effects of periodontal disease. Tooth loss occurring in the maxilla, generally result in bone resorption both apically and palatally. Problem of compromised alveolar ridge may be in addition to maxillary sinus varying in size and shape and thus requiring surgical intervention for implant placement. Unless cavity following tooth extraction is filled in to maintain alveolar ridge, maxillary sinuses pneumatize after tooth loss and expand in such a way thereby compromising or preventing implant placement without an augmentation procedure.

Following are the most common requirements for sinus lift procedure.

• Resorbed alveolar crest under the maxillary sinus must be of a minimum height say about 5mm for placement of implant.
• Following sinus augmentation procedure, implant may surgically be placed after a minimum healing period of 6 to 12 months varying from patient to patient.
• Development of maxillary posterior for the atrophic ridge either through sinus graft or ridge augmentation procedure require bone graft material which could either be autugraft, allograft, xenograft or synthetic material and many a times accompanied by the use of GTR membrane.

Bone Graft materials can be categorized in following four types.

• Autograft or autogenous bone graft i.e. patients own bone.
• Allograft or allogenic bone graft i.e. of same species.
• Xenograft or xenogenic bone graft i.e. of two different species (bone of bovine origin).
• Alloplast or alloplastic i.e. Synthetically derived, which could either be hydroxyapatite, ß-TCP or any formulation thereof, bone graft.

Ideal bone graft/replacement material should exhibit four characteristics namely

• Osteointegsation, the ability to chemically bond to the surface of bone without an intervening layer of fibrous tissue
• Osteoconduction, the ability to support the growth of bone over its surface
• Osteoinduction, the ability to induce differentiation of pluripotential stem cells from surrounding tissue to an osteoblastic pleno type and
• Osteogenesis, the formation of new bone by osteoblastic cells present within the graft material.

Some of the applications of BioGraft Bone Regenerative/Substitute materials are the following.

• For socket preservation following extraction of a tooth or to augment an atrophied or resorbed site.
• For sinus lifting preceding placement of dental implants.
• For ridge expansion.
• For treatment of Periodontitis.

Periodontitis is a chronic inflammatory disease of the periodontium occurring in response to bacterial plaque on the adjacent teeth, characterized by gingivitis, destruction of alveolar bone and periodontal ligament, apical migration of the epithelial attachment resulting in the formation of periodontal pockets and ultimately loosening and exfoliation of the teeth.

Bacteria in our mouth along with mucus and other particles, constantly form a sticky, colorless 'plaque' on teeth. Unless such plaque is removed by brushing and flossing, the same hardens and form bacterial harboring 'tartar'. Plaque and tartar on teeth, cause inflammation of gums called 'gingivitis' and unless treated advance to 'periodontitis'. Factors like Smoking, Diabetes, Stress etc are found to accelerate periodontitis.

Some of the symptoms may be the following:

• Sensitive teeth.
• Mobile teeth
• Pain during chewing
• Red swollen gums
• Tender or bleeding gums
• Bad breath
  

Periodontitis is generally treated either by scaling and root planing or medications or surgery. Type of treatment vary from patient to patient and objective is to control the infection. Surgery include Flap Surgery and Bone Graft Surgery. Grafting in addition to flap surgery, is done to replace or encourage new growth of bone or gum tissue destroyed by periodontitis and BioGraft bone regenerative materials in this regard are useful.

Why Synthetic Bone Grafts are preferred for filling bony defects?

Because they have desired consistency, particle size, porosity and strength with availability in abundance in sterile condition. These features totally eliminate donor site morbidity and risk of viral transmission associated with Autogenous grafts and Xenografts respectively.

What are 'Bio Ceramic' materials?

Ceramics are oldest man made material consisting of non-metallic inorganic substances. Bio Ceramics are those ceramics which are used to repair and reconstruct diseased or damaged parts of the body.

What are the types of Bio Ceramics?

Calcium Phosphate based Ceramics are being used in various disciplines of medicine i.e. Orthopaedics, maxillofacial surgery, spinal surgery, dentistry for augmentation of alveolar ridge etc..

Two forms of Calcium Phosphate Ceramics receiving most attention are the following:

• Synthetic Hydroxyapatite (HA) and
• Beta Tri-calcium Phosphate (TCP)

This is because these two forms have mineral composition similar to that of natural bone, bio-compatible and bond well with natural bone. Their bio-compatibility makes them successful bone substitutes. These have been found to be safe and effective for a variety of clinical applications.

Composition both Synthetic Hydroxyapatite and Beta Tri-calcium Phosphate are called Biphasic Calcium Phosphate Ceramic material.

Studies have shown that BCP has osteo inductive properties. HA implants have successfully been used to prevent post extraction alveolar ridge resorption. BCP has the combined advantages and properties of both HA and TCP.

HA is the natural mineral component of vertebrate hard tissue, comprising 60-70% of bone and 98% of of dental enamel. HA in appropriate synthetic form is generally found to be bio-active and non-bio-resorbable. HA has osteoconductive potential.

TCP is clinically similar to HA but is not a natural component of bone. It is partially resorbable and is often considered desirable for repair of non-pathological site. This act as temporary space filler or scaffolds for new tissue to develop. Natural tissue reconstruction occurs simultaneously with resorption of the ceramic.

Calcium phosphate bio-materials are devoid of local or systemic toxicity, do not elicit inflammatory or foreign body response, can become functionally integrated with natural bone with no fibrous tissue encapsulation and cause no alteration of normal bone minerlization process. Also they become bonded to bone by apparently natural bone cementing mechanism.

Calcium phosphate bio-material provide a physical matrix suitable for deposition of new bone and can display growth guiding properties causing bone to extend its growth into areas it would not otherwise occupy. It also has the ability to maintain bone bulk in areas where bone resorption normally takes place.

BioGraft-HA and BioGraft-HT are available in Granule size range of 0.25 mm (250 microns) to 4 mm (4000 microns). These materials can also be made in other Granule sizes requested for.

These Products are being marketed with Shelf Life of 3 years. Yes, these Products are sterilized by Gamma Ray irradiation.

These Granules are wetted either with patient blood or PRP (Patelet Reinforced Plasma) or saline solution and placed directly on application area in conjunction with Guided Tissue Regeneration Membrane (GTP) and followed by sutures.

Yes these materials are available in different pre-formed shapes like square, rectangle, cone, triangle, circular, semi-circular etc in different standard sizes of appropriate porosity. Pre-forms of specific design and sizes can also be made available.

No but pre-forms are meant for filling of larger voids.