METHODS: A literature search was performed in 3 electronic databases for articles published before August 2018. Randomized clinical trials published in English that compared PP between machine-assisted agitation and syringe irrigation with needles as part of nonsurgical root canal treatment were included. Two authors were independently involved in the article selection process, data extraction, and assessment of the quality of included studies using the revised Cochrane risk of bias tool. The pooled effect estimates of the standardized mean difference (SMD) between machine-assisted agitation and syringe irrigation with needle was calculated by a random effects-modeled meta-analysis. A subgroup meta-analysis was performed. The quality of evidence was evaluated by the Grading of Recommendations, Assessment, Development and Evaluations approach.

RESULTS: Six studies were included for systematic review. Meta-analysis was performed using 3 studies and showed that machine-assisted agitation resulted in less PP compared with syringe irrigation with needle at 24 hours (SMD = -0.73; 95% confidence interval, -1.04 to -0.42; I2 = 30.6%) and 48 hours (SMD = -0.60; 95% CI, -0.85 to -0.35; I2 = 0%). The quality of evidence by Grading of Recommendations, Assessment, Development and Evaluations for the PP outcomes (24 hours and 48 hours) was graded as "moderate" quality.

METHODS: We searched 3 major databases, i.e., PubMed, Embase and Lippincott Williams & Wilkins Journals@Ovid, for studies published up until 1May 2013 without language restrictions. All study designs were included in this review. The studies were identified and retrieved by two independent authors.

RESULTS: Of 118 titles scanned, 14 duplicates were removed, and a total of 13 abstracts from all three databases were identified for full-text retrieval. From the full text, eight articles met the inclusion criteria for this systematic review. These articles showed acceptable quality based on our scoring system. Most of the studies indicated that temporary threshold shifts were much lower when subjects were exposed to a noise level of 85 dBA or lower.

METHODS: The review protocol was registered in the PROSPERO database (CRD42017071899). A literature search was performed in the MEDLINE and EBSCOhost databases until June 2017 with no language restriction. Randomized controlled trials evaluating the efficacy of oral premedications, whether given alone or in combination, compared with other agents, placebo, or no treatment in adult patients before NSRCT for postoperative pain were included. Nonintervention studies, nonendodontic studies, animal studies, and reviews were excluded. The quality of the studies was assessed using the revised Cochrane risk of bias tool. Pair-wise meta-analysis, network meta-analysis, and quality of evidence assessment using the Grading of Recommendations Assessment, Development and Evaluation criteria was performed.

RESULTS: Eleven studies comparing pharmacologic groups of medications were included in the primary analysis. Compared with placebo, corticosteroids (prednisolone 30-40 mg) was ranked best for reducing postoperative pain (median difference [MD] = -18.14 [95% confidence interval (CI), -32.90 to -3.37] for the pain score at 6 hours; MD = -22.17 [95% CI, -36.03 to -8.32] for the pain score at 12 hours; and MD = -21.50 [95% CI, -37.95 to -5.06] for the pain score at 24 hours). However, the evidence was very low (6 and 24 hours) to moderate quality (12 hours). Nonsteroidal anti-inflammatory drugs were ranked least among the medications, and the quality of this evidence was very low. Additional analysis based on the chemical name showed that sulindac, ketorolac, and ibuprofen significantly reduced pain at 6 hours, whereas piroxicam and prednisolone significantly reduced the pain at 12 and 24 hours. Etodolac was found to be least effective in reducing pain. Overall, the evidence was of moderate to very low quality.