The systemic application of fluoride has rendered enamel more resistant to decalcification and decay. While the incidence and severity of dental caries has decreased, the diagnosis of caries in this enamel environment has created significant new challenges and dilemmas. Traditional diagnostic methodology and treatment philosophy no longer seem appropriate. This article describes the historical perspectives, current diagnostic challenges, and the treatment dilemmas of occlusal pit-and-fissure systems currently facing the dental profession.