Statistical Analysis This will be performed by an independent statistician appointed by National Safety Associates Inc. All three study hypotheses presume that two subjects with the same initial attachment level and pocket depth would have the same expected final attachment level and pocket depth, except for the effect of their respective treatments. Therefore, the first two hypotheses will be investigated by using Analysis of Covariance, with the 3 month value of attachment level or pocket depth as a response, initial value as a covariate, and treatment as a study factor. Hypothesis 3 will be investigated in a similar fashion, except that the response will be the 9-month measurement.