The aim of this study was to assess the effectiveness of
low-level laser therapy (
LLLT) for
pain management after root canal treatment or
retreatment. An electronic search for randomized controlled trials was conducted prior to November 2018, through PubMed, EMBASE, the Cochrane library (CENTRAL), and Web of Science. After filtering, seven articles were included, five related to
root canal therapy (RCT) and two related to root canal
retreatment (RCR). Six of the included studies presented a moderate risk of bias and a one low risk of bias, based on the Cochrane tool of risk of bias evaluation. The
laser treatment included
diode laser and
indium-
gallium-
aluminum laser.
LLLT was compared with placebo, blank, and
ibuprofen treatment. Clinical outcome variables included the prevalence of
pain,
pain intensity, and need for
analgesics after treatment. Three studies showed
LLLT could reduce the prevalence of
pain significantly after RCT or RCR. Although the effect of
LLLT on
pain intensity varied at different observation time points and among different studies, most of them found patients had lower
pain intensity in the
LLLT group. Of the three studies that assessed the need for
analgesics after treatment, two studies showed significant benefits. Based on the current evidence, the use of
LLLT for
pain control in postendodontic
therapy may be promising. However, solid conclusions should not be drawn definitely, given that more high-quality randomized controlled trials are required to further evaluate the efficacy of
LLLT for
pain management after RCT and RCR.