Adult patients ( n = @ , = @ , = @ ; mean age SD : @ @ ) from three participating centers , diagnosed with root caries , were randomly allocated into two groups : Test ( n = @ , = @ , = @ ; lesions = @ ; mean age : @ @ ; intervention : high-fluoride toothpaste with @ ppm F ) , and Control ( n = @ , = @ , = @ ; lesions = @ ; mean age : @ @ ; intervention : regular-fluoride toothpaste with @ ppm F ) groups .