Clinical, microbiological and oxidative stress evaluation of periodontitis patients treated with two regimens of systemic antibiotics, adjunctive to non-surgical therapy: A placebo-controlled randomized clinical trial

Abstract

Aim of research was to evaluate and compare the clinical and microbiological effects of two different regimens of amoxicillin (AMX) and metronidazole (MTZ) combined with non-surgical periodontal therapy in patients with chronic periodontitis (CP), and identify antibiotic-resistant bacteria and changes in oxidative stress (OS). Forty-six patients with generalized CP were randomly assigned to group A [scaling and root planing within 24 h (SRP) + placebo for 7 days), group B [SRP + AMX + MTZ, both 500 mg three times daily (TID), 3 days), and group C [SRP + AMX + MTZ, both 500 mg TID, 7 days). Periodontal pocket depth (PPD-primary outcome), clinical attachment level (CAL), full-mouth bleeding scores (FMBS), plaque scores (FMPS), blood and subgingival plaque were assessed at baseline and after three months. OS was evaluated via derivatives of reactive oxygen metabolites (d-ROMs) and assessments of biological antioxidant potential (BAP). Bacterial profiling was performed by PCR. Antibiotic resistance was evaluated in cultures. PPD, CAL, number of sites with PPD ≥6 mm, their PPD, CAL and FMBS decreased (P<0.05) in all groups, as well as FMPS in groups A and B, and d-ROMs in group C. There were significant differences among groups regarding decreases in the frequency of detection for Aa and Tf. For Aa, there were differences between groups A and C (P=0.048) and between groups B and C (P=0.048), but not between groups A and B; whereas for Tf, groups A and B were different from group C (P<0.001), but not from each other (P=0.920). No resistance to AMX was identified prior to treatment; two strains were resistant after treatment. Before treatment, 13 strains were resistant to MTZ, and 2 were resistant after. One strain in the same patient was sensitive prior to treatment, and later became resistant to both antibiotics. SRP with a 7-day course of antibiotic therapy was more effective for improving clinical parameters, in decrease of detection of several periopathogens, and in improvement of OS when compared to a 3-day regimen. Resistance was found in fewer strains after treatment than before.

Keywords: antibiotic resistance; antibiotics; bacteria; oxidative stress; periodontitis; root planing.

Figure 1.

Flow-chart of the study protocol. SRP, scaling and root planing; AMX, amoxicillin; MET, metronidazole; PCR, polymerized-chain reaction; d-ROM, derivatives of reactive oxygen metabolites; BAP, biological antioxidant potential; TID, three times daily.

Figure 2.

Scatterplot and regression lines showing the relation between the changes at three months in the number of sites with a PPD ≥6 mm and the baseline number of sites with a PPD ≥6 mm for group A, nonsmokers (black), smokers (red); group B, nonsmokers (blue), smokers (light blue); group C, nonsmokers (gray), smokers (green).