FACTORS AFFECTING PERIODONTAL BONE REPAIR

FACTORS AFFECTING PERIODONTAL BONE REPAIR

Najam-us-Sahar

Abstract

Background: Bone graft, Chitosan and Bone Marphogenetic Protein-2 are selected  among  different factors affecting or elicit the bone regeneration. These factors have been evaluated by many researchers. The properties and limitation of these factors are discussed in this article.  

Objective: To compile and analyze various published research results related to Periodontal Bone Repair.

Study design: Analytical and comparative study

Methods: Reviewed most of the research articles related to the Periodontal Bone Repair. Categorize the factors or materials that enhance the efficacy of the regeneration of periodontal bone.

Conclusion: Many researches have been conducted for evaluation of Bone regeneration. Latest techniques with different materials should be practiced to speed up the bone repair process.

 

INTRODUCTION

Bone is an integral part of the human body that forms a framework  which is attached to the muscular system. Bone has ability to rebuild itself after getting damaged. It has a natural process of healing through Osteons. The Osteons are formed when bone gets injured. It is a  tough supporting structure that  always undergoes  the process of remodeling. For interpreting the basic concept of healing, it is indispensable  to see the Pathophysiology of bone defects.

The bone defect is formed when bone gets insulted or hurt. The gap is  brought out at the lieu of injury, filled with necrotic bone debris, blood from broken blood vessel and inflammatory cells. Cells and signals combined to act on the necrotic debris to remove and then create  new bone  by forming scaffold  for the new generating bone.

Bone Structure	Ratio of both bones	% of remodeling (per year)
Cortical Bone	9	3%
Cancellous Bone	1	30%
All Human Body Bones		6%

Periodontal bone defects are usually caused by trauma, fracture, surgery, tumor, Periodontitis, Osteoporosis and Arthritis. The most common cause of periodontal bone defect is Periodontits –  the inflammation of Periodontium, which leads to the underneath bone loss.

Natural remodeling process in human bones:

As remodeling occurs, Osteoblastic cells produced new  bone cells and Osteoclastic bone cells destroyed or resorbed existing bone. This formation and resorption process called Remodeling. Failure in maintaining the balance of remodeling results in multiple problems like Osteoporosis and Arthiritus. 

Bone regeneration techniques and materials

With the help of different materials, Periodontal bone can be regenerated through different techniques.

Bone Grafting

Bone grafting is the replacement of injured bone by some substituting material. It can be natural as well as synthetic. There are three kinds of bone grafting materials – Osteogenesis, Osteoinduction and Osteoconduction. The bone formation originates from the cell or tissue, which is contained in Osteogenisis material. The protein or growth factor that effects on proliferation and differentiation progenitor cells (that present in clot or granulation tissue) forms a new bone. The growth and replacement of new bone occur with the help of Osteoconductive material which forms scaffold for the new bone.

Bone grafting materials	Function
Osteogenisis	Helps in Bone formation
Osteoindution	Proliferation and differentiation of proginator cells
Osteoconductive	Replacement of new bone by making scaffold

Properties of Ideal Bone Grafting Material                        

Bone grafting material has to be Biocompatible, safe, non-toxic, non-allergic and should contain no risk of disease transmission. Its composition and particles should be alike to human bone and  also have space maintaing capability. The resorption rate should also be similar to human bone.

Types of Bone Grafting

Autogenes: This type of bone graft comes from the same individual. It is called “Gold Standard”, that satisfies all the requirements of ideal grafting material.

Allogenic: This type of bone graft comes from the different individual of the same specie.

Xenogenic: This type of bone graft comes from some other species, i.e. cow, horse etc.

Alloplastic or Synthetic: This is the type of bone graft made up with different formulation of Calcium and Phosphate.

Limitation Of Bone Graft

Bone substituting materials for bone grafting have been used with good clinical efficacy, but it has some limitation like bone resorption, low biodegradability,  poor adaptation and immune response. They work only on the physical scaffold for bone tissues. These materials may require  several months or years to form new bone.

Effects of Chitosan on Periodontal Bone Repair

Chitosan is the derivative polymer which is made  by deactylation of Chitin. Chitin is mainly present in exoskeleton of Crutaceans and in some Fungi.

The properties of Chitosan include high Osteoinductivity, Osteointegratability, easy application and gradual biodegradability. These qualities make Chitosan a good material for bone regeneration. Chitosan is a biodegradable and biocompatible substance.

The minimal inflammatory reaction is also observed when Chitosan coated pins are in contact. It is also used in biochemical coating for Orthopedics and Crainiofacial implants. The Vascularization of blood vessels is increased with Chitosan. It increases the activity of Osteoblasts that leads to bone formation and also can increase Osteogenesis. It also helps in the proliferation of Osteoblastic cells. Kim and co-workers studies found that Chitosan can also work on tissue engineering such as it forms skin,  bone and cartilage. The present studies also reveal the effect on bone regeneration. Zhang and his co-workers, research found Chitosan as a Biocompatible and Biodegradable Polymer, if used with Mannitol and Calcium Phosphate cements for bone healin . It can be used for shaping Hydroxyapatite in surgeries and implants. They also used Tetra Calcium Phosphate with Chitosan to form non-rigid and strong Calcium Phosphate Cement that used in repairing of periodontal tissues and bone surrounding implants. Bumgardner and co-workers also revealed that Chitosan is a Biopolymer that elicit the procedure of bone formation, facilitates the healing procedure and has Tri-microbial properties.

Ma and Co-workers reported that Chitosan Thermosensitive Hydrogel rhBMP-2 facilitates regeneration of the periodontal tissues. Chitosan Hydrogel is used by injecting in the lesion . As their study revealed,  it is not only helped in bone regeneration, it also  maintained the bone density. Zhang  and co-workers used Chitosan scaffold for the regeneration of Alvealar bone in dental implants. They found Chitosan scaffold can also be used in bone regeneration. Chitosan is considered a good alternative of bone graft. It also improved the bone regeneration of periodontal bone loss.

Chitosan is poorly soluble in water or any oraganic solvent;  limiting its uses. Another limitation of Chitosan is its higher degree of swelling in aqueous environment.  

Recombinant human bone Morphogenetic Protein-2 stimulated Priodontal bone regeneration

Recombinant human bone Morphogenetic Protein-2 consist of Fibronectin and other Glycoproteins. Urist and his co-workers studied revealed that when untreated decalcified bone matrix is  implanted in muscular pouch, the formation of cartilage and bone is stimulated.

Bone Morphogentic Protein-2 sequestered in a decalcified bone matrix, responsible for the induction of new bone. Bone Morphogenetic Protein-2 is  evaluated in Mandibular and Cleft Palate reconstruction, Sub Antral, Alveolar Augmentation, Dental Implant Fixation and Periodontal Indication.

It is also  observed, the Ankylosis of the tooth with the newly formed bone. Ankylosis is evaluated to compromise healing. This limits the uses in flexible gross architecture.

METHODOLOGY

The literature search for this article were based on research papers. Most of  research papers were about  bone regeneration and selected three factors, bone graft, Chitosan and Bone Morphogenetic Protein-2, for comparison. The selection criteria are  based on the usage, properties of material,  researcher’s recommendation and better evaluation  of  the material. The bibliography of the selected research papers is also included in the review as additional reference.

DISCUSSION

Bone Graft has been used commercially, in spite of its limitations like deficiency to achieve ideal bone properties. It also needs surgery to implant graft and suffered with postoperative complication and infection transmission, etc. Although it posses significant clinical efficacy. Chitosan has  Biocompatible and Anti-Microbial properties. It is used commercially in different drugs. The uses are limited due to poor solubility in water and it swells up in Aquous medium. After long efforts of several researchers,  Bone Morphogenic Protein is now available commercially. There are some hurdles like, how to deliver the molecules in fashion to obtain consistent bone formation.  It was observed that Bone Morphigenic Protein rapidly cleared from the surgical site, thus need a carrier which can maintain the Protein molecule at the surgical site and act as a scaffold for new bone.

CONCLUSION

The significant research has been conducted about Bone Grafting, Chitosan and Bone Morphogenic Protein. It is concluded that these factors are useful to elicit bone repair.  After many researches, these materials are now available commercially. However, this is  more important that the gross number of patients can get benefit from these materials.