Fibrin Sealants in Orthodontics - An Overview

Introduction:

Fibrin sealants are insoluble blood clotting agents made externally and used to arrest bleeding. Fibrin sealants can be obtained from a bovine source or in the laboratory. It has been in development and used for over a century now. The first fibrin mesh was used as a clotting agent in the year 1909 by Bergel. The first sealant (use of fibrin as a glue) was used in 1940 by Young and Madawar and in 1972 by Matras nerve attachment. This fibrin sealant patch was approved by the FDA (food and drug administration) in 2010. the application of fibrin sealants was of greater help in cases that required faster healing or in patients who could not naturally clot effectively.The fibrin sealants comprise two factors called thrombin and fibrinogen, along with clotting factors eight and calcium which, when used, gets converted to fibrin that forms a blood clot.

What Is a Fibrin?

Fibrin is an insoluble protein formed from the fibrinogen during the clotting cycle. Fibrin is a fibrous protein formed by the action of thrombin on fibrinogen to form a fibrous plug using platelets to arrest bleeding.

What Is a Fibrin Sealant?

Fibrin is a blood clotting agent consisting of two substances, fibrinogen, and thrombin, the natural blood clotting agents in the body. Blood clotting occurs in a cycle where the thrombin converts the fibrinogen into an insoluble fibrin mesh. Fibrin sealant is the only material used in three ways: hemostat, sealant, and adhesive. Also, it is the only commercially available hemostat in patch form.

How Does Fibrin Act in the Body?

When a blood clotting protein, thrombin, gets activated by an enzyme called fibrinogen, multiple fibrin or clot fragments, several pieces are produced, and clot-forming agents react with factor 8 (a factor in the blood cycle), inducing blood clots.

What Are the Sources From Which the Fibrin Sealant Is Derived?

The sources approved by the FDA (food and drug administration) from which fibrin sealants are derived are:

• Pooled Human Plasma - It is obtained by collecting whole blood from the donor through an FDA-approved collection center where the plasma is gained from centrifugation. The collected plasma is then frozen immediately.

• Individual Human Plasma Liquid - It is obtained from a single donor plasma.

• Bovine Collagen - It is a hydrolyzed protein substance occurring commonly in the connective tissues, bones, cartilage, and hides, widely used as a food supplement.

• Thrombin - It is a protein substance used to convert prothrombin into thrombin, which activates clotting factors. This is available in a frozen form.

• Equine Freeze Dried Collagen - It is a modified type of collagen derived from horse tissues.

• Oxidized Regenerated Cellulose - It is a chemically made or laboratory-altered agent used to arrest bleeding.

What Is the Role of Fibrin Sealants in Orthopedics?

Fibrin sealants help in blood clotting, fixing the tissues, improving tissue plasticity, improving material placed inside the bone, and stimulating bone growth. The efficiency of the bone growth induced by fibrin sealant is still being studied; the use of fibrin sealants is known to be an excellent choice in orthopedic surgery and trauma. Some of the orthopedic surgeries in which a fibrin sealant is used are:

• Use of Fibrisas a Bone Adhesive - The fibrin sealant is used as an adhesive to bind all the bony fragments as it generates the formation of new bone cells and promotes faster healing.

• Use of Fibrin in Knee Surgery - During the replacement of knee implants with advanced structure, there is an evident loss of blood which is unavoidable. Although there are steps to prevent the blood, it remains questionable, and the amount of blood loss is around 1400 ml (milliliter). Hence in such conditions, fibrin sealant comes to aid as they induce clotting of blood. Here the bone blood clotting fibrin glue is applied before placing the implant, followed by injecting other clotting agents like tranexamic acid for clotting of the blood vessels, which reduces the blood loss from 1400 to 235 ml.

A combination of the fibrin sealant with thrombin gel shows a marked effect in arresting the bleeding. Platelet gel is a collagenous substance rich in platelet and growth factors, both the platelet gel and fibrin sealant. When both are mixed together in the patient's blood, and during implant placement, this procedure is successful and shows an excellent prognosis, although the usage of tranexamic acid should be kept under watch.

• Articular Cartilage Injuries - The injury to the cartilage can be extensive, from bone-cartilage-bone extending up to a fracture. Here the use of fibrin sealants for cartilage tissues is a well-established one. The use of fibrin Sewell-established for treating cartilage defects after trauma and weak chondral bodies (cartilage bodies) has been in existence since the early 1980s. Fibrin glue is used vastly in all forms of autologous chondrocyte implantation (ACI), which cultivates the cartilage cells in vitro (outside the body). Although the fibrin glue is not a definite bone cell-forming agent, it helps in the migration of the cartilage-forming cells. This acts as a major advantage in the use of fibrin as a sealant.

• Meniscal Tear - Although the meniscal repair procedure is a viable procedure to treat the tear of the meniscus (ligament near the bone), it needs a very prominent blood supply to be successful. Fibrin glue acts as an adhesive by holding the torn meniscus and as an enriched pool of growth factors.

• Damage to The Anterior Cruciate Ligament - The use of fibrin in treating ACL (anterior cruciate ligaments) has existed since the 1980s. It was used in the treatment of hamstring repair or bone-patella- bone grafts. The use of fibrin, along with growth factors, showed the formation of new fibers resembling Sharpey's fibers within the tendon of the bone. This, in turn, increased the biomechanical strength of the fibrous cartilage.

• Benign Bone Tumors - Fibrin sealant is used to treat tumors showing excessive bleeding and cysts (fluid or gas-filled cavities) around the synovial joint. Here the healing is induced by extracting the cystic fluid and injecting fibrin. This seals the orifice of the tumor or cyst preventing it from refilling.

What Are the Advantages of Fibrin Sealant?

Fibrin sealant is a multipurpose agent, and its usage is highly beneficial. The advantages of fibrin sealant are:

1. Induces faster healing.

2. Shows excellent biocompatibility.

3. Promotes cell growth by attracting the growth cells.

4. Serves as a medium for cell growth.

5. Acts as a cell glue or adhesive.

6. Aids in arresting bleeding.

What Are the Drawbacks of Using Fibrin Sealants?

Fibrin sealants do have a few disadvantages, and they are:

1. It can be expensive.

2. Can transmit infection when not screened properly.

3. The body can sometimes reject the use of fibrin from a bovine source.

Conclusion:

Although fibrin sealants have some disadvantages with the cost and screening when monitored and placed, they are an excellent source for the body and bone enriched with nutrients to promote and induce better cell growth and healing. An improvement in technique and methods of utility will also nullify the limitations we have towards it and improve the efficacy of the sealant. Hence, use of fibrin sealants is an excellent treatment of choice while treating bone and associated lesions.