Effect of ultrasonic activation on the reduction of bacteria and endotoxins in root canals: a randomized clinical trial

Abstract

Nakamura VC, Pinheiro ET, Prado LC, Silveira AC, Carvalho APL, Mayer MPA, Gavini G. Effect of ultrasonic activation on the reduction of bacteria and endotoxins in root canals: a randomized clinical trial. Journal, 51, e12-e22, 2018. Aim This randomized clinical trial aimed to compare the effectiveness of ultrasonic activation with that of nonactivated irrigation on the removal of bacteria and endotoxin from root canals. Methodology Fifty patients with necrotic pulps and asymptomatic apical periodontitis were randomly allocated into two groups according to the final irrigation protocol after root canal preparation: Group UIultrasonic irrigation (n = 25) and Group NI -needle irrigation (n = 25). The root canals were medicated with calcium hydroxide for 14 days. Microbiological sampling was performed before (S1) and after the root canal preparation (S2), after the irrigation protocols (S3) and after the removal of the intracanal medication (S4). Total bacteria counts were determined by qPCR and the endotoxin levels by the limulus amebocyte lysate assay. Intragroup analyses were performed using the Wilcoxon test for related samples, whereas intergroup analyses were performed using the MannWhitney U-test (P < 0.05). Results All S1 samples were positive for bacteria, with median numbers of 1.49 9 10 6 and 8.55 9 10 5 bacterial cells for the UI and NI groups, respectively. This number significantly decreased in S2 samples (UI: 1.41 9 10 4 ; NI: 3.53 9 10 4 ; both with P < 0.001). After final irrigation protocols, there was a significant decrease in bacterial load from S2 to S3 samples in both groups (UI: 4.29 9 10 3 ; NI: International Endodontic1.08 9 10 4 ; P < 0.01). Intergroup analysis revealed a significant difference between irrigation methods regarding bacterial counts in S3 samples (P < 0.05). In contrast, no significant differences were observed between groups for endotoxin levels (P > 0.05). Conclusions Ultrasonic activation was more effective than nonactivated irrigation for reducing the number of bacteria but not the endotoxin levels in root canals of teeth with apical periodontitis.

Endotoxin levels after chemomechanical preparation of root canals with sodium hypochlorite or chlorhexidine: a systematic review of clinical trials and meta‐analysis

“…Moreover, it seems that greater the volume of irrigation used, greater was the LPS reduction (Nakamura et al . ). All the four studies included in this review reported a similar sequence and volume of the chemical auxiliary substances used during chemomechanical preparation (Gomes et al .…”

Efeito da ativação ultrassônica da pasta de hidróxido de cálcio na atividade metabólica de bactérias em canais radiculares: Estudo clínico randomizado

“…Esse estudo foi realizado de acordo com as normas CONSORT (Consolidated Standards of Reporting Trials) para estudos clínicos randomizados. A metodologia utilizada para as coletas e análises microbiológicas foi baseada em estudos clínicos prévios (Pinheiro et al, 2015;Nakamura et al, 2018).…”

“…Os procedimentos clínicos foram realizados na Clínica de Pós-Graduação da (Nakamura et al, 2018). Os critérios de inclusão foram: pacientes com diagnóstico de necrose pulpar (confirmado pela resposta negativa ao teste de sensibilidade ao frio com gás refrigerante) e periodontite apical assintomática.…”

“…Os critérios de exclusão foram: pacientes que utilizaram antibióticos nos últimos 3 meses; dentes com perda de tecido dentário que impossibilite o isolamento absoluto; dentes com câmara pulpar aberta/ exposta ao meio bucal; dentes com bolsa periodontal superior a 4 mm; dentes com evidência radiográfica de tratamento endodôntico prévio, ápice aberto, fratura, reabsorção ou calcificação. Além disso, dentes com uma curvatura maior que 20º (Schneider, 1971) As coletas microbiológicas foram realizadas de acordo com estudos prévios (Nakamura et al, 2018).…”

“…A primeira etapa do tratamento endodôntico, o preparo químico-cirúrgico (PQC), é considerada a etapa de maior importância para a redução de bactérias dos canais radiculares. O presente estudo evidenciou uma redução significativa do número de cópias de rDNA bacteriano após o PQC, confirmando os achados prévios (Vianna et al, 2006;Sakamoto et al, 2007;Rôças et al, 2010;Rôças et al, 2011a;Rôças et al, 2011b;Paiva et al, 2012;Paiva et al, 2013a;Paiva et al, 2013b;Rôças et al, 2013;Neves et al, 2014;Rôças et al, 2014;Rodrigues et al, 2015;Provenzano et al, 2015;Zandi et al, 2016;Neves et al, 2016;Rôças et al, 2016;Rodrigues et al, 2017;Nakamura et al, 2018;Nardello, 2018). Esse fato se deve ao contato dos instrumentos endodônticos com as paredes dos canais radiculares, promovendo a remoção ou desorganização mecânica do biofilme bacteriano.…”