Glossary

This term means that an object or material has an effect on or elicits a response from living tissue. In dental applications, bioactive materials are essential as implants, prostheses, and other structures must properly interact with the teeth, gums, tongue, and other tissues of the mouth. Metal oxides are frequently used to create bioactive dental structures since they have the ability to form chemical bonds with living tissues. These bonds build a stable scaffold upon which new cells can grow in preparation for an implant procedure or as part of the healing process. Bioactive materials are essential in medical and dental procedures as they help reduce the risk of infection or rejection in the affected tissues as well as in the tissues surrounding the procedure site. The specific bioactive material used can depend upon the type of procedure, the dental structure needed, and even the preference of the dental professional.

Bioactive fixation refers to stabilization involving direct physical and/or chemical attachment mechanism(s) between biological tissues and a dental implant surface at the ultra-structural level. Materials such as zirconia are often used in dental implants, however, they can require surface treatment in order to stimulate osseointegration. Studies have shown that the creation of a nano-porous surface on such materials allows for the chemical coating of different bioactive substances which has led to increased implant osseointegration and fixation. Other materials used are directly bioactive meaning they require no additional treatments for the enhancement of fixation. These include bioactive glass which has the capacity to bond with soft and hard tissues for stable fixation. In addition, bioactive glass is biocompatible, strong but lightweight, and can be used as a support structure as long as needed. The use of bioactive materials for fixation of dental implants can lead to increased stability, attachment, and success of the implant.

Bioactive glass is an absorbable alloplastic material composed of the metal oxides SiO2 , Na2 O, and P2 O5. It forms a chemical bond with living tissues thereby helping to stabilize a filled defect site and to maintain a rigid scaffold upon which cells can migrate and grow. Bioactive glass causes the tissues surrounding it to produce a substance which closely resembles hydroxyapatite. This in turn allows the glass to aid in the bioactive fixation of an implant through its ability to bind to both hard and soft tissues. Bioactive glass is a lightweight but strong material. Though it is also biodegradable, its composition can be adjusted so that it lasts in the tissues for a specific amount of time to provide support as long as required. In addition, bioactive glass is biocompatible, meaning it won’t stimulate an immune response from the body which could jeopardize the success of the implant.

Bioceramics are a specially designed and fabricated ceramic material used in the repair or reconstruction of diseased, damaged, or missing parts of the body. Materials classified as bioceramics include zirconia, alumina, glass ceramics, bioactive glass, calcium phosphates, and hydroxyapatite. In dentistry, endodontics, and periodontology, bioceramics are often used in surgeries, such as alveolar ridge augmentation, and in implant composition. They are also commonly used as sealers following a root canal. They are especially useful in this application as their composition won’t lead to rejection by the body and its final structure is similar to the structure of the natural teeth. A disadvantage in their use as a sealer, however, is the difficulty associated with removing them from a root canal if later treatment is required. Bioceramics are a bioactive material, meaning they interact with the hard tissues around it. In addition, bioactive materials have both osteoconductive and osteoinductive properties which allow it to bond with natural bone.

Biocompatible refers to the property of a material to elicit or perform without a negative host response (immune response or inflammation) in a specific application. In general, biocompatibility is measured on the basis of allergenicity, carcinogenicity, localized cytotoxicity, and systemic response. A material that is biocompatible can be used within the body without concerns regarding the long-term negative effects that may be associated with other commonly used, but not biocompatible, products. In dentistry, silver amalgam fillings have been a standard choice in tooth repair for many years. However, the mercury content in such fillings poses questions regarding toxicity for patients who have them. Recent advancements in dentistry have led many dental professionals and patients to biocompatible choices for filling materials such as plastics, resins, porcelain, or other composites. There are now also many dentists who work with only biocompatible materials to reduce the risk of toxicity to the patient throughout their life.

The term bioinert refers to any material that does not elicit a response from the host. The body’s immune system is designed to identify and target foreign substances, even those placed in the body to aid it in some way, and therefore will attack and attempt to destroy the substance. In order to prevent this, special materials have been developed that do not create a negative response from the body’s immune system. Such substances can be classified as bioactive, biotolerant, and bioinert. Bioinert materials allow the bone and tissues surrounding it to re-grow and integrate without causing any negative immune response. In dentistry, bioinert materials are an essential component of implants, bone grafts, prostheses, and fillings. In addition to not harming the body, a bioinert substance in dentistry will also be osteoconductive and promote osteogenesis. Such materials aid the body in providing a stable foundation for future dental work.

Biointegration is the bonding of living tissue to the surface of a biomaterial or implant, independent of any mechanical interlocking mechanism. It is often used to describe the bond to hydroxyapatite-coated dental implants. Biointegration is essential to the success and longevity of the implant. Once the fixture has been placed in the bone, new bone cells should begin to grow around it, bonding with the fixture surface. This allows the fixture to integrate into the surrounding bone to provide a stable foundation for the abutment and implant. Successful biointegration can depend on several factors including the quality and quantity of existing bone around the implant, the structure and material of the fixture and implant, when loading of the implant takes place, and the oral health and hygiene of the patient. Patients who experience successful biointegration generally have a low risk of implant failure after the first year following the procedure.

Translated literally, the word “biomimetic” means to mimic life. Biomimetic applications in dentistry aim to conserve natural teeth whenever possible. Fractured, weak, and decayed teeth are treated to maintain strength and resist bacteria. This dental approach has reduced the need to file down teeth for root canals and crowns. A biomimetic approach to implant dentistry utilizes biocompatible materials like titanium to better promote osseointegration between the bone and the implant. Different physicochemical characteristics of the implant surface can affect osseointegration and typically, the surface of the implant will be sandblasted or acid-etched to encourage successful implantation. With a biomimetic approach, however, designed peptides and extracellular matrix components may be used as a way to modify the implant surface. Biomimetic dental implants are continually being developed and tested as new ways to achieve osseointegration. Additionally, bone grafting procedures in biomimetic dentistry are cutting edge, using multi-material 3D printing for the scaffold design.

The word “bioresorbable” means biodegradable, or “naturally absorbing”. For example, a bioresorbable stent or bioresorbable stitches will eventually be absorbed by the body over time. In implant dentistry, bioresorbable materials are often used in guided bone regeneration, or bone grafts. Various animal studies were done to compare the difference between bioresorbable barrier membranes and nonresorbable membranes over a period of six months. In multiple studies, the nonresorbable membranes were shown to have slightly better outcomes than bioresorbable membranes in regards to the regeneration of bone. However, there are significant benefits to using bioresorbable membranes in clinical practice. The primary benefit is that a second procedure to remove the membrane is not necessary, because the body will have absorbed it on its own. This also helps patients avoid risks associated with a second procedure, including anesthesia risks and gingival recession. Although nonresorbable membranes may generate slightly more bone than bioresorbable membranes, many periodontists and patients choose bioresorbable membranes.

When bone grafting is necessary prior to placing a dental implant, many dentists in the past used autologous bone grafting, since it had long been considered the gold standard in bone reconstruction. An autologous bone graft involves removing bone from one part of the patient’s body and putting it in another. However, over time as newer technology became available, it was realized that autologous bone grafting may not be the best option. The procedure results in a second surgical site to harvest the bone and still the quantity of bone available for harvest may be limited. A second surgical site also opens the door for additional complications. Autologous bone graft alternatives include biomaterials like biphasic calcium phosphate (BCP) ceramics and have been proven effective during clinical trials. BCP’s are now considered the new gold standard in bone grafting and bone reconstructive surgery due to their excellent osteoconductive properties and the elimination of a second surgical site.