Abstract
Dear Editor,
We have read the response from Yang and Huang 1 to our Letter in which we shared our experiences with low-level laser therapy (LLLT) in burning mouth syndrome (BMS) treatment. 1 The authors have commented on three issues from our letter that could potentially represent an explanation of different findings from their study, 3 concluding that we lack evidence that LLLT serves as a placebo in BMS treatment.
The first conclusion about laser parameter differences would have been acceptable had we not achieved great improvement in the placebo group as well. Should it have been the case that we didn't see improvement in active group or in both groups, one could argue that we used insufficient laser energy. But in this case, as we did achieve statistically significant improvement in both groups, even in placebo group when using 0 (zero) J/cm2, we find it hard to consider laser parameter differences as an acceptable argument.
The second conclusion was about a “better analgesic result in the laser-treated group after day 5 even though it was not statistically significant“. Indeed, we obtained some fluctuations of mean visual analog scale (VAS) score differences over the treatment period, but both the pattern shown and a lack of statistical significance offer less than an evidence of superiority over placebo.
The third conclusion was on the VAS score measurements. You either can measure millimeters on a 100-mm line, or express the score in percentages, but this would not influence or change the results. We have used the 150-mm VAS (intensity increase from left to right). The Y-axis represents VAS score in percentages calculated by dividing the distance in mm from the left end to the marked position by 150. Either way would provide the same figures for statistical analysis, and therefore is irrelevant.
Our experience clearly showed a lack of real evidence of superiority of LLLT over placebo in treating this particular condition famous for its "iatroplacebogenesis", making the last two sentences (which considered our thesis that LLLT had a placebo effect on BMS “too arbitrary”) unsustainable.