PROTECTION OF BOVINE ENAMEL AND DENTIN BY CHLORHEXIDINE AND FLUORIDE VARNISHES IN A BACTERIAL DEMINERALIZATION MODEL

In an in vitro demineralization model, the protective effect of two ch lorhexidine varnishes, Cervitec(R) (1% w/w chlorhexidine diacetate and 1% w/w thymol) and EC40(R) (40% w/w chlorhexidine diacetate), was com pared with that of Fluor Protector(R), a varnish containing 0.1% w/w F . The demineralization model comprised an acidogenic Streptococcus mut ans suspension in agarose placed on enamel or dentine specimens. The e xperiments extended over three serial 22-hour demineralization periods with fresh S. mutans suspensions for each period. To determine whethe r the varnishes released enough demineralization-inhibiting compounds, approximately 10 mu l of the varnishes was applied adjacent to the en amel and dentine specimens just before the first application of the S. mutans suspensions and left during the serial experiments (release st udy). In a separate series of experiments, the effect of the pretreatm ent of the enamal and dentine specimens with the various varnishes was tested (pretreatment study). In the release study the protective effe ct for enamel decreased in the order: EC40 = Fluor Protector >> Cervit ec = no treatment. For dentine this order was: EC40 >> Fluor Protector = Cervitec > no treatment. In the pretreatment study, the enamel spec imens were best protected by Fluor Protector (Fluor Protector >> Cervi tec = EC40 > no treatment), while the dentine specimens were best prot ected by the chlorhexidine treatments (Cervitec = EC40 > Fluor Protect or > no treatment). A 1:1 mixture of Cervitec and Fluor Protector was as effective as the most effective component alone. It is concluded th at a varnish containing both fluoride and chlorhexidine may be useful, since it could give optimal protection to both enamel and dentine.