Restorative Dentistry and Chitosan

Ihe quest for interactive or bioactive dental restorative materials is not a totally new endeavor in dental materials. For example, as a general concept, glass ionomer cements (GICs) have been endorsed as a bioactive material because of their dynamic release of fluoride, as well as their unique mineral-based poly-salt matrix composition that is claimed to also contribute to the ability to remineralize calcium-depleted tooth structure. The continuous release of fluoride by GICs and resin-modified glass ionomers (RMGIs) has also been positioned as a potential mechanism to delay or inhibit secondary caries at teeth restored with these materials at the margins of the restorations [47,48]. 

The potential benefits of the use of adhesive monomers both in free-standing dentin-enamel adhesives and in self-adhesive formulations are still somewhat areas of debate. Current restorative resin/dentin adhesive systems have demonstrated outstanding long-term clinical performance in prospective clinical studies [49-53]. 

We have approached the problem of adhesion from a slightly different angle as part of om continuous interest in developing functional chitosan-based hydrogel systems that utilize a concept of bioadhesion and bioactivity to create an ideal interface for bonding of dentin and restorative material as well as provide therapeutic support at the site of action [74-80]. 

The term bioadhesion refers to any bond formed between two biological stu-faces or a bond between a biological and a synthetic surface [81]. In the case of bioadhesive drug delivery, the term bioadhesion is used to describe the adhesion between polymers, either synthetic or natural, and soft tissues or the gastrointestinal mucosa [81]. 

In cases where the bond is formed with the mucus, the term mucoadhesion may be used synonymously with bioadhesion [81]. Mucoadhesion can be defined as a state in which two components, of which one is of biological origin, are held together for extended periods of time with the help of interfacial forces. Generally speaking, bioadhesion is a term which broadly includes adhesive interactions with any biological or biologically derived substance, and mucoadhesion is used when the bond is formed with a mucosal surface. 

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