“…The best effects have been obtained when an extra layer of polyurethane sealant (Sandham et al, 1988 or bonding resin (Fure and Emilson, 1990) has been applied over the chlorhexidine varnish, which increased the retention of chlorhexidine on the teeth for up to approximately five days . Without an extra layer, the long-term effect seems to be highly dependent on the concentration of Based ondata from: Emilson, 1981;Emilson and Fornell, 1976;Emilson etal.,1976;FureandEmilson,199a,Gisselssonetal.,1988Johansen et al, 1975Katz, 1982;Keltjens et al, 1990;Kristoffersson and Bratthall, 1982;Lindquist et al, 1989, Luoma et al, 1978Maltz et al, 1981;Mikkelsen et al, 1981;Ostela et al, 199Q0 Persson et al, 1991;Petersson et al, 1991;Sandham et al, 1988Sandham et al, ,1991Schaeken and De Haan, 1989, Schaeken et al, 1986, 1991aSpets-Happonen et al, 1985von der Fehr et al, 1975;Zickert et al, 1982;Zyskind et al, 1990. chlorhexidine in the varnish. A dose-response effect has been observed in plaque studies in which a varnish containing 40% chlorhexidine was found to be more effective against mutans streptococci than a varnish containing either 10 or 20% or 25 or 33% (Schaeken et al, 1991b).…”