Journal of Dentistry and Oral Epidemiology were used in the meta-analysis of each outcome. We
dose-response gradient). Each one of these topics was
calculated the means difference and the 95 % confidence
assessed as “no limitation”; “serious limitations” and “very
interval (IC). Heterogeneity was assessed using the Cochran
serious limitations” to allow categorization of the quality of
Q test and I2statistics.
the evidence for each outcome into high, moderate, low, and
The quality of the evidence was graded for each outcome
very low. The “high quality” suggests that we are very
across studies (body of evidence) using the Grading of
confident that the true effect lies close to the estimate of the
Recommendations:
and
effect. On the other extreme “very low quality” suggests that
Evaluation (GRADE) to determine the overall strength of
we have very little confidence in the effect estimate and the
evidence for each meta-analysis. The GRADE approach is
estimate reported can be substantially different from what it
used
was measured.
to
Assessment,
contextualize
or
Development
justify
intervention
recommendations with four levels of evidence quality,
Results:
ranging from high to very low.
After the database screening and removal of duplicates, 1741
The GRADE approach begins with the study design (RCTs
studies were identified (Figure 1). After title screening, 62
or observational studies) and then addresses five reasons (risk
studies remained. This number was reduced to 13 after
of bias, imprecision, inconsistency, indirectness of evidence,
examination of the abstracts and their full texts were assessed
and publication bias) to possibly rate down the quality of the
to check eligibility. Among them, 4 were excluded because:
evidence (1 or 2 levels) and three to possibly rate up the
i) Botox was also used in the control group [21]; and ii) not
quality (large effect; management of confounding factors;
checked the intensity of myofascial pain [22-24].
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