Dental silicate cement 255- 8 fluoride release

The glass polyalkenoate cement uniquely combines translucency with the ability to bond to untreated tooth material and bone. Indeed, the only other cement to possess translucency is the dental silicate cement, while the zinc polycarboxylate cement is the only other adhesive cement. It is also an agent for the sustained release of fluoride. For these reasons the glass polyalkenoate cement has many applications in dentistry as well as being a candidate bone cement. Its translucency makes it a favoured material both for the restoration of front teeth and to cement translucent porcelain teeth and veneers. Its adhesive quality reduces and sometimes eliminates the need for the use of the dental drill. The release of fluoride from this cement protects neighbouring tooth material from the ravages of dental decay. New clinical techniques have been devised to exploit the unique characteristics of the material (McLean Wilson, 1977a,b,c Wilson McLean, 1988 Mount, 1990). 

The dissolution and ion release from dental silicate cement have been the most investigated characteristics with good reason, for they are central to its clinical performance. Erosion limits its life but release of fluoride has important clinical consequences. 

Kuhn Jones (1982) examined various models for fluoride release and showed that release did not fit the membrane and homogenous monolith model. Instead, they concluded that the cement behaved as a porous granular monolith, as described by Kydonieus (1980). The release of fluoride appears to be an ion exchange phenomenon, as dental silicate cement takes up rather than releases fluoride from solution if it is present in sufficient concentration (Kuhn, Lesan Setchell, 1983). 

Aluminium ions released from the dental silicate cement are also absorbed by hydroxyapatite and have a similar beneficial effect to that of fluoride (Halse Hals, 1976 Putt Kleber, 1985). Thus, the dental silicate cement confers protection against caries (dental decay) on surrounding tooth material. 

One advantageous biological property possessed by dental silicate cement is the sustained release of fluoride this has been discussed in Section 6.5.7. 

Silicophosphate cement acts as an agent for the sustained release of fluoride, although different cements behave very differently (Wilson, Crisp Lewis, 1982). Silicophosphate cement has a disability in the mouth similar to that of dental silicate cement. It is less resistant to oral fluids than glass polyalkenoate cement, but more resistant than all other dental cements, as is shown by both in vivo studies (Norman et al., 1969 Ritcher Ueno, 1975 Clark, Phillips Norman, 1977 Mitchem Gronas, 1978 ... 

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