The agreement between workers and within workers in regard to occupational exposure to mercury in dental practice assessed from a questionnaire and an interview

Table 5 Agreement within workers for the number of years they had used the three treatment methods, heated copper amalgam, a mortar and a Dentomat.

Question	number of comparisons	From interview	From questionnaire	Mean difference	Std of the mean difference	50 percentile	90 percentile
Number of years with copper amalgam	47	7.6(5.2)	9.1(5.4)	3.7	3.5	2.0	9.2
Number of years with use of a mortar	22	6.6(4.2)	8.8(7.2)	5.8	5.9	5.0	14.4
Number of years with use of a Dentomat	61	16.6(8.5)	16.9(9.1)	5.9	5.6	4.0	15.8

The difference is the mean difference for the absolute value of the differences on the number of years given at the interview and the number of years given in the questionnaire for those who had used that method. The 10, 50 and 90 percentiles for the differences between the interview and the questionnaire are also given.

ISSN: 1745-6673