Efficacy of Amoxicillin-metronidazole Compared to Clindamycin in the Treatment of Periodontitis in Patients With Diabetes

A parallel, randomized, double-blind, active controlled, single center clinical trial was designed to compare the efficacy of two antibiotic therapies with 24-month follow-up. The study protocol was approved by the ethical committee of the Universitary Center of Health Sciences of University of Guadalajara and conducted according to Good Clinical Practice and the principles of the Declaration of Helsinki. All patients provided written informed consent before the initiation of study procedures.

A total of 5 non-study subjects with chronic periodontitis were recruited and used for the calibration exercise. Two designated examiners measured full-mouth probing pockets depths (PPD) for all 5 subjects. On the same day (with a minimum of 15 min separation), the examiner repeated the examination. Upon completion of all measurements, the intra-examiner repeatability for PPD measurement was assessed. The examiner was judged to be reproducible after fulfilling the pre-determined success criteria (the percentage of agreement within 2 mm between repeated measurements had to be at least 70 %). The examiner showed 78.3 % reproducibility.

The sample size was calculated with a 95% confidence level and statistical power of 80 %. A standard deviation of 1.0 mm with an expected difference of 1.0 mm probing pocket depth reduction between treatments. This resulted in a total of 14 patients per arm, however this sample was increased 20% (21 patients per group) to compensate for possible dropouts.

Patient population Criteria for selection Patients of both sexes (aged >18 to 70 years) with a diagnosis of chronic periodontitis according to the 1999 International World Workshop for a Classification of Periodontal Diseases and Conditions and a history of type 2 diabetes with a HbA1C < 8 % and a fasting plasma glucose (FPG) < 180 mg/dL. Patients with aggressive periodontitis, pregnant or lactating females, required antibiotic pre-medication for the performance of periodontal examination and treatment or received antibiotic treatment in the previous 3 months were excluded. A history of anti-inflammatory therapy within preceding six months or that had received a course of periodontal treatment within the last 6 months, allergies to penicillin, metronidazole or clindamycin, and were not able to provide consent to participate in the study were also criteria for exclusion.

Intervention Subjects were randomly allocated 1:1 to receive 500 mg amoxicillin + 250 mg metronidazole or 300 mg clindamycin + placebo using a computer that generated a list of random numbers. Subjects were instructed to take the treatment three times a day for 7 days in both groups.