This objective is tracked using the Oral Health Examination component of the Continuous National Health and Nutrition Examination Survey, collected since 1999. The measurement protocol has been described. A description of the clinical protocol used to confirm evidence of protective dental sealants has been published by NCHS. The teeth included in the measurement protocol for each age group differ. For ages 3 to 5, primary molars are included – due to eruption patterns, this includes 1st and 2nd primary molars For ages 6 to 9, only first permanent molars are tracked. For ages 13 to 15, both 1st and 2nd permanent molars are tracked, and to be included in the numerator sealants must be present on both a 1st molar and on a 2nd molar.