The sol-gel dipping process, in which liquid silicon alkoxide is transforme
d into a solid silicon-oxygen network, can produce a thin film coating of s
ilica (SiO2). The features of this method are high homogeneity and purity o
f the thin SiO2 film and a low sinter temperature, which are important in t
he preparation of coating films that can protect metallic ion release from
the metal substrate and prevent attachment of dental plaque. We evaluated t
he surface properties of dental pure titanium casting coated with a thin Si
O2 or SiO2/F-hybrid film by the sol-gel dipping process. The metal specimen
s were pretreated by dipping in isopropylalcohol solution containing 10 wt%
3-aminopropyl trimethoxysilane and treated by dipping in the silica precur
sor solution for 5 min, withdrawal at a speed of 2 mm/min, air-drying for 2
0 min at room temperature, heating at 120 degrees C for 20 min, and then st
oring at room temperature. Both SiO2 and SiO2/F films bonded strongly (abov
e 55 MPa) to pure titanium substrate by a tensile test. SiO2- and SiO2/F-co
ated specimens immersed in 1 wt% of lactic acid solution for two weeks show
ed significantly less release of titanium ions (30.5 ppb/cm(2) and 9.5 ppb/
cm(2), respectively) from the substrate than noncoated specimens (235.2 ppb
/cm2). Hydrophobilization of SiO2- and SiO2/F-coated surfaces resulted in s
ignificant increases of contact angle of water (81.6 degrees and 105.7 degr
ees, respectively) compared with noncoated metal specimens (62.1 degrees),
The formation of both thin SiO2 and SiO2/F-hybrid films by the sol-gel dipp
ing process on the surface of dental pure titanium casting may be useful cl
inically in enhancing the bond strength of dental resin cements to titanium
, preventing titanium ions release from the substrate, and reducing the acc
umulation of dental plaque attaching to intraoral dental restorations, (C)
1999 John Wiley & Sons, Inc.