Tratamento da periodontite experimental em ratos com clorexidina como adjuvante à terapia periodontal não-cirúrgica

Abstract

Periodontitis is caused by subgingival bacterial communities with virulence potential. These bacteria cause tissue rupture and/or trigger destructive immunopathological responses of the host which, in turn, lead to the destruction of the supporting periodontal tissue and may cause eventual loss of teeth. Scientific evidence indicates that microorganisms present in subgingival biofilms can cause direct and indirect damage to the periodontium. The indirect damage can be caused by the activation of host immune responses that result in the degeneration of the periodontal tissues. The treatment of periodontitis is based on the removal of pathogenic subgengival microbiota by scaling and root planing (RAR). However, systemic and local factors, such as areas of difficult access to periodontal instruments, may compromise the effectiveness of periodontal treatment. Therapeutic interventions involving different drugs to RAR treatment have been investigated. This study evaluates the effects of subgingival irrigation using 0.12% or 0.2% chlorhexidine (CHX) as adjuvant to mechanical treatment of periodontitis induced in rats. Periodontitis was induced by means of a cotton ligature tied subgengivally around the first lower left molar in ninety rats. The ligature was removed after seven days and the animals were divided into the following groups: 1) RAR group, scaling and root planing (RAR) and subgingival irrigation with 0.9% saline solution (n = 30); 2) RAR + 0.12% CHX, RAR group and irrigation with 0.12% CHX (n = 30); 3) RAR + 0.2% CHX group, RAR and irrigation with 0.2% CHX (n = 30). Ten animals from each group were sacrificed at 7, 15 and 30 days after treatment. The furcation region was analyzed histometrically to determine the area of bone loss. Data were analyzed using Kruskal-Wallis univariate analysis of variance (ANOVA) followed by the Dunn test (p<0.05). Both groups of chlorhexidine presented lower inflammation and better tissue repair throughout the experiment when compared with the RAR group. In the histometric analysis at 7, 15 and 30 days, the RAR group (4.58 ± 2.51 mm2, 4.21 ± 1.25 mm2, 3.49 ± 1.48 mm2) presented greater bone loss (p> 0.05) than the RAR + 0.12% CHX groups (1.86 ± 1.11 mm 2, 0.79 ± 0.27 mm 2, 0.34 ± 0.14 mm 2) and RAR + 0.2% CHX (1.14 ± 0.51 mm 2, 0.98 ± 0.40 mm 2, 0.41 ± 0.21 mm 2), respectively. Subgingival irrigation with chlorhexidine appears to have anti-inflammatory properties with histoprotective characteristics during the treatment of periodontitis.