On 2014 Feb 02, Jan Tunér commented:

It is interesting to note that the authors themselves state the origin of "burning mouth" as multifactor, psychosomatic or psychogenic. Thus, there would be no actual injury to the tissue, and laser, like any other modality, would have no effect. The negative 5-HIAA measurement in the laser group may indeed confirm the inappropriate inclusion parameters and laser energies in this study.

On 2014 Feb 02, Jan Tunér commented:

It is interesting to note that the authors themselves state the origin of "burning mouth" as multifactor, psychosomatic or psychogenic. Thus, there would be no actual injury to the tissue, and laser, like any other modality, would have no effect. The negative 5-HIAA measurement in the laser group may indeed confirm the inappropriate inclusion parameters and laser energies in this study.