Aim:The purpose of this pilot study was to determine and compare the effects of two protocols aimed at reducing periodontal inflammation, upon the metabolic control of the diabetic condition in subjects with elevated baseline glycosylated hemoglobin (HbA1c). Methods and Materials:Forty-two non-smoking type 2 diabetes subjects with mildly elevated HbA1c (>7 but < 9%) and severely elevated (>9%) were randomized to one of two non-surgical periodontal therapy protocols. Patients in the "minimal therapy" (MT) group received scaling, root planning, and oral hygiene instructions on two occasions six months apart. Participants randomized to the "frequent therapy" (FT) protocol received scaling, root planing, and oral hygiene instructions at two-month intervals and were provided a 0.12% chlorhexidine rinse for home use twice daily. Neither systemic nor local antibiotics were provided to either group. Subjects were asked to report any changes in diabetic medications, nutrition, and physical activity. Data analyses (ANOVA, t-test, Mann-Whitney) grouped subjects according to baseline HbA1c (>7 and < 9%, or > 9%), treatment protocol (minimal or frequent), and +/-medication change. Results:In both MT and FT groups the clinical attachment level (CAL) remained unchanged but the other measures [gingival index (GI) and pocket dept (PD)] of periodontal health improved. Mean reductions in plaque showed improvement but calculus was worse in the FT group, likely due to the use of chlorhexidine. At six months, the largest reduction of HbA1c was 3.7; experienced by a subject receiving FT but no changes in diabetic medication. Among the MT and no medication change subjects, the maximum reduction was 1.6. Abstract © Seer PublishingConclusion: Overall, modest improvements in HbA1c were detected with a trend towards FT being better than MT. Although this pilot trial was under-powered to detect small between-group differences, the magnitude of our findings (0.6 mean improvement in HbA1c) matches closely findings from the only meta-analysis conducted on this topic to date. Larger scale studies must be undertaken on diabetic patients with periodontal problems.Clinical Significance: Preventive periodontal regimens for diabetic patients should be sufficiently intense and sustained to eliminate periodontal inflammation and should be closely coordinated with the patient's overall clinical diabetic management.