Bioactive Materials in Dentistry: A Groundbreaking Review

Bioactive Materials in Dentistry

As we all know, the traditional materials commonly used in dentistry are passive and inert, i.e. they exhibit little or no interaction with body tissues and fluids. In the past, materials were thought to be ideal and biocompatible based on their ability to sustain without interacting with the oral environment. However, the current trends are changing due to the advancements in material science. Many of the advanced materials are required to be functionally beneficial, playing an active part, thereby working with dental tissues to remineralize and heal them - Bioactive Materials in Dentistry. Materials used in dentistry can be classified as bioinert (passive), bioactive, and bioresponsive or smart materials based on their interactions with the environment.

Bioactive Materials in Dentistry

As the name suggests, a bioactive substance is one that has an effect on a living organism, tissue or cell. The concept of bioactivity was first introduced in 1969 and later defined by Cao and Hench in 1996. In general, it refers to a specific property of a material that has an effect on or will elicit a response from a living tissue or cell, such as induc­ing the formation of hydroxyapatite. Perhaps the benefits of fluoride release from materials attracted the use of active materials rather than passive ones in dentistry. However, bioactivity is not just limited to fluoride release and the conversion of hydroxyapatite to its stronger form of fluorapatite anymore! The definition of bioactivity in dentistry is expanding by leaps and bounds due to the emergence of bioactive dental materials in the market. Some of the Bioactive Materials in Dentistry available are calcium hydroxide, mineral trioxide aggregate (MTA), calcium enriched mixture (CEM), Biodentine, Doxadent, Ceramir, Bioaggregate, Activa BioACTIVE restorative material, MTYA1-Ca filler, tetracalcium phosphate (TTCP), Theracal, sol-gel-derived bioactive glass (BAG) ceramic containing silver ions (Ag-Bg), calcium phosphate, fluoro calcium phosphosilicate, novel endodontic cement (NEC), endo sequence root repair material. The ideal properties of Bioactive Materials in Dentistry are: bactericidal or bacteriostatic, sterile, stimulate reparative dentine formation and maintain pulp vitality. The bioactive materials have been put to various uses in dentistry such as pulp capping material, permanent restorations, root canal therapy, dentinal tubule occlusion in dentinal hypersensitivity cases, to act as scaffold to help in the regeneration of bone tissue, for tooth repair & regeneration, periodontal regeneration, to promote tooth remineralization, bone grafts, implant coating etc.

Significance of Bioactive Materials in Dentistry

Bioactive Materials in Dentistry are currently a significant topic of interest in restorative dentistry for regeneration, repair and reconstruction. This is evidenced by the change in the com­positions of restorative materials away from inert “fillers” and more toward being biologically adaptive materials. A bioactive dental restorative material is one that forms a layer of hydroxyapatite when immersed in a simulated body fluid or a solution containing inorganic phosphate. This is possible by induction of various growth factors to stimulate nat­ural mineralization. Imagine being able to re-calcify a carious tooth?? Sounds amazing! Isn’t it?? It’s no longer an imagination! The advent of bioactive dental materials has made it a possible reality. The luting and restorative materials that have been used in the past merely restore the form and function of the tooth, but are not influential on the activity of the oral environment. They do not provide a continuous seal, resulting in micro-leakage and marginal failure of crowns, inlays, and veneers. Furthermore, these materials typically function at a continuous and constant pH, which causes the materials to fail, creating crevices where plaque can build up and secondary caries even before the restoration fails. On the other hand, bioactive restor­ative materials, such as bioglass, glass-ceramic, calcium phos­phate ceramic, composites, and coatings, are able to stimulate the biological tissue of the tooth and/or bond to living tissues. Therefore, the hope for bioactive materials is that they will prevent micro-leakage by forming apa­tite, which will provide a continuous seal to the margins between the restoration and tooth thereby extending the life of the restoration. Moreover, bioactive materials may also help to re-establish minerals lost to caries. Apart from that, bioactive materials are considerably less harmful to local and generalized tissues. Additionally, these materials have been shown to considerably enhance the aesthetic outcome of restor­ative dental procedures. This evolution of materials and compo­sitions that display greater interactions with tooth structure is the drive for the future, as seen by the following trend of bioac­tive material compositions from zinc phosphate to polycarboxylate to glass ionomer cements.