ABSTRACT
INTRODUCTION Many outcomes in dentistry are binary (e.g., presence or absence of oral cancer). In Chapter 9 it was seen that a binary outcome in a sample is summarized by calculating the proportion of the sample with a given outcome (e.g., proportion of the sample diagnosed with oral cancer). Dental treatments are often evaluated by comparing a treated group with an untreated (control) group. For instance, the outcome might be the proportions of patients who experienced no pain with new and established anesthetics. If the treatment is “effective,” the proportion with the favorable outcome in the treatment group will be higher than that in the control group. Alternatively, we might want to investigate whether people with a high sugar intake are more likely to lose their molars before the age of 65 years compared with people who consume little sugar. If there is no association between sugar intake and loss of molars, the proportion with their molars remaining at 65 years will be the same for those with and without a high sugar intake.
