This systematic review will be conducted under the guidance of Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA-S)(26) and the Cochrane Handbook for Interventional Reviews. Our protocol is registered with the International Prospective Register of Systematic Reviews (PROSPERO-CRD#42019099141).
Review Question: What is the most effective adjunctive irrigation or disinfection technique in decreasing bacterial load (antimicrobial effect) from the root canal system during primary root canal therapy in patients with apical periodontitis compared to standard needle syringe irrigation method?
Types of Studies
This systematic review will include two kinds of study designs: one, randomized controlled trial with parallel groups and other Before-and-after study design in which microbial sample protocol S1, S2 and S3 is followed. In this protocol, the bacterial sample is taken before access preparation(S1), after chemo-mechanical preparation (S2), and after the use of adjunctive disinfection technique (S3).
Types of Participants
Adult patients who are diagnosed clinically and radiographically as pulp necrosis/apical periodontitis will be included. It will include both symptomatic and asymptomatic apical periodontitis. The review is limited to primary root canal therapy. However, there is no restriction to types of tooth; all kinds of single-rooted or multi-rooted teeth will be included.
Immature teeth, primary teeth, and previously root treated teeth with secondary infection will be excluded.
Intervention
The intervention is supplemental or adjunctive disinfectant techniques, i.e., passive sonic and ultrasonic irrigation, apical negative pressure, photodynamic therapy, ozone gas.
Comparator
Standard chemo-mechanical techniques, which are involved in debridement with rotary and hand instrumentation followed by irrigation with sodium hypochlorite with the help of a needle syringe technique, will be comparator.
Outcome
Primary Outcome
Data on the antimicrobial efficacy of the adjunctive disinfection technique will be collected in studies following S1, S2, and S3 protocol. However, data on bacterial load evaluation after further application of any intracanal medicament (S4) will not be extracted.
Antimicrobial efficacy evaluated by bacterial culture technique or polymerase chain reaction (PCR) will be measured in terms of:
- Binary outcome as a negative and positive bacterial culture
- continuous outcome in the form of mean, range, and standard deviation of colony-forming units count (CFU). Both kinds of data binary and continuous (whichever is available) will be collected.
- Bacterial reduction in percentage.
Secondary Outcome
Other relevant secondary outcomes will be taken into count.
Data sources and search strategies
Electronic databases MEDLINE (Ovid), EMBASE (Ovid), and Cochrane library will be used from their inception to September 2019. There will be no restriction on language to any database.
We will also search for the clinical trial registry: http://clinicaltrial.giv. Hand searching of references for searched studies, existing systematic reviews, and endodontic journals will be carried out. We will also search
Two reviewers (SD, ZA) will work on the study selection process according to prespecified inclusion and exclusion criteria. Studies selected from all databases will be transferred to Endnote reference manager software (X8), where duplication of studies will be identified and removed. Initial screening of studies will be done on the basis of title and abstract. Then full-text articles of studies will be retrieved. The whole process of study selection will be presented as the PRISMA flow diagram(26).
The data extraction will be performed on a structured Microsoft Word & Excel sheet. Details of study characteristics that include patient/problem, characteristics of the intervention, comparison, and outcome measures will be documented. One reviewer (DS) will extract data and will be crossed checked by the other reviewer (ZA).
Authors of included studies will be contacted where necessary information is needed.
Language
Any language
Risk of Bias Assessment
The Cochrane Risk of Bias assessment tool will be used for assessing the risk of bias in the included studies. The studies will be classified as low, high, and unclear risk of bias based on the following six domains:
Random sequence generation: This is related to how studies generate a random sequence for equal distribution of patients in experimental and control groups. Online randomizers, coin tossing, and random number tables are considered an acceptable way of randomization.
Allocation concealment: This domain determines whether the allocation of patients to various groups was adequately concealed from patients and operators. Studies that performed central allocation, sequentially numbered opaque sealed numbers are at low risk of bias while those used open number random allocation, date of birth, rotation will be considered at high risk of bias.
Blinding of participants, operators, and outcome assessors: Blinding is related to performance and detection bias. Studies, where lack of blinding or blinding of crucial personnel did not affect outcomes measures, will be considered at low risk of bias. However, studies where lack of blinding or incomplete blinding was found to affect outcomes, will be rank as high risk of bias.
Incomplete outcome data: If studies with no missing data or missing data are compensated across intervention groups, it will be considered at low risk. A high attrition rate and lack of intention to treat analysis will be considered at a high risk of bias.
Selective reporting bias: The included studies will be assessed for the reporting of all relevant outcome measures. Any discrepancy will be considered at a high risk of bias.
Overall quality of each study will be considered as "low" risk of bias when all the domains scored low, "some concerns" when at least one domain was scored as some concern and "high" when at least 1domain scored as high or more than two domains as some concern.
Any disagreement between two reviewers (DS and ZA) will be resolved by discussion or by consulting the third reviewer (IP).
Data synthesis
The unit of analysis in this review is a tooth. The antibacterial efficacy is presented in the form of both continuous and dichotomous outcomes. We will collect both kinds of data available. For a dichotomous outcome, we will measure the risk ratio with 95% confidence interval. Continuous outcomes will be presented as weighted mean difference (WMD) with 95% CI or Standardized mean difference (SMD) with 95% CI in case if different measuring scales are used. The pooled estimate of the treatment effect will presented by using an appropriate model.
If sufficient homogeneity in terms of methodology and interventions among studies is found, meta-analysis using a fixed effect or random effect model will be conducted. Tests of heterogeneity (Chi-square) and I2 statistic will be conducted. If substantial heterogeneity is found (I2 >75%, or P<0.1), it may not be possible to conduct a meta-analysis, then a qualitative narrative summary of findings will be presented. The potential sources of heterogeneity will be explored by the methods of subgroup analysis and meta-regression.
Quality of evidence will be judged using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. Quality of evidence for each relevant outcome will be rated as high, moderate, low, and very low.
Publication bias in the included studies will be assessed by a funnel plot.