Antibiotic Study for Dental Implants

At Visit 1, the dentist will: * do an oral exam * ask some questions * decide if the person qualifies for being in the study * make an appointment for Visit 2 if they qualify At Visit 2 (Baseline), the dentist will: * do a special cleaning of the implants * examine the whole mouth * collect some fluid * take x-rays * put the people into one of two groups (taking into account whether or not they smoke) 1. one group will have the study antibiotic put on all the areas in their mouth with gum problems 2. the other group will not receive the antibiotic At Visit 3 (about a month later), only fluid samples will be collected. At Visit 4 (about 3 months later), the dentist will: * collect fluid samples * examine the whole mouth * apply the antibiotic again for people in that group At Visit 5 (about 6 months later), the dentist will: * collect fluid samples * examine the whole mouth * take x-rays