Abstract
In vitro topical applications of acidulated phosphate fluoride (APF) and titanium tetrafluoride (TiF4) were compared in terms of fluoride uptake, penetration and artificial lesion formation. Higher fluoride values were found in the APF-treated halves, but less lesion formation occurred in the TiF4-treated halves. TiF4 applications formed an acid-resistant surface coating which was not removed after a 24-hour washing.