Does an interim dressing with calcium hydroxide reduce endotoxins between endodontic appointments?

Abstract

Data sources PubMed, Cochrane Library, LILACS/Biblioteca Brasileira de Odontologica, Web of Science, Embase, Scopus, grey literature.Study selection Randomised and non-randomised clinical studies, experimental studies. Population: human studies with permanent dentition; Intervention: evaluation of lipopolysaccharide (LPS) after dressing with calcium hydroxide (CH); Comparison: evaluation of LPS before dressing with CH; Outcome: antimicrobial efficacy against LPS.Data extraction and synthesis A modified Cochrane Risk of Bias (RoB) tool was used to evaluate internal validity of randomised controlled trials, Robins-1 tool for non-randomised controlled trials, and the 'Before and After' tool for experimental studies. Meta-analyses were conducted by subgrouping according to CH use, chemo-mechanical preparation (CMP), antimicrobial substance (AS), and irrigant. Further analyses explored incidence of LPS reduction. All subgroups were assessed for heterogeneity through I2 test and the random-effect model was applied. Sensitivity analysis was performed to evaluate the influence of studies with RoB in effect significance.Results Nine studies were included for qualitative assessment, of which seven were included for meta-analysis. Three studies were assessed as low RoB, one was medium risk, with two having a high RoB. Three studies presented with 'some concerns'. After dressing with CH, no AS resulted in 61.7% of teeth with reduction in LPS (95% CI: 37.7%-82.9%, I2 = 96.7%), compared to AS where 98.9% of teeth showed an LPS reduction (95% CI: 97.4%-99.8%, I2 = 38.6%). Where mean reductions in LPS were compared, CH with or without AS, reduced mean LPSs before (standardised mean difference [SMD] = 21.087 [CI: 21.453 to 20.721], P = 0.001, I2 = 58.7%) and after CMP (SMD = 20.919 [CI: 21.156 to 20.682], P = 0.001, I2 = 24.7%) using a CH dressing. Considering the irrigant solutions, the overall results showed a reduction before (SMD = 21.053 [CI: 21.311 to 20.795], P = 0.001, I2 = 58.7%) and after CMP (SMD = 20.938 [CI: 21.147 to 20.729], P = 0.001, I2 = 24.6%) using a CH dressing. There was a reduction in mean LPS over time, up to 30 days. All analyses presented a very low certainty of evidence.Conclusions An interim dressing with CH reduces LPS levels below those achieved with CMP and AS, but does not eliminate LPS completely. No evidence is presented on improved clinical outcomes following multiple-visit treatment with CH dressing.