Abstract
R
The inclusion criteria allowed for studies in which “LLLT was applied to the test side and a pseudoapplication was used on the placebo side” in human studies. I understand the appeal of this form of control group, but as a general rule, split-mouth LLLT studies produce false negatives because LLLT has systemic effects 17 –19 , i.e., treating one side of the mouth can affect the placebo side. The authors acknowledge this phenomena, so to insist on split-mouth studies only and to exclude the possibility of more reliable placebo group studies (by LLLT standards) is a strange stance to take and means the authors might have missed some important articles.
The exclusion criteria also excluded studies in which “non-laser light sources were used” so, on that basis, LED articles would be missing (although I found just one LED article). The exclusion criteria also excluded studies “in which canine retraction was not carried out by a closed-coil spring”, so Sentalloy, helical spring, and elastomeric separators were left out.
The inclusion criteria allowed for studies in which there were “retraction movements on molar and canine teeth” only, so incisor movement articles would be excluded. Also, pain only studies were excluded because this was a tooth movement review. This is a valid approach, but readers should be aware that some interesting data exists outside the criteria used in this review. I appreciate that if a meta analysis were being conducted using a broader selection criteria, it would have been harder to demonstrate the efficacy of the LLLT treatments. However, as the review was more narrative, I believe that the full range of articles could have been included and discussed.