For more than 30 years, pit and fissure sealants have been recommended for caries prevention, along with good oral hygiene, optimal fluoridation, and healthy dietary habits. To be effective in the prevention of pit and fissure caries, a sealant must truly 'seal', i.e. it must completely keep out fermentable food substrates. The pits and fissures are approximately eight times as vulnerable for dental caries as the smooth surfaces. In practice, the benefit of sealing should be considered locally and specified guidelines for clinicians should be used. As part of the evidence-based approach to care, these clinical recommendations should be integrated with the practitioner's professional judgment and the patient's needs and preferences. This review demonstrates that there is some degree of latitude in operator preferences for sealant placement and material selection. Sealants should be placed as part of an overall prevention strategy based on assessment of caries risk.