- Jul 2018
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europepmc.org europepmc.org
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On 2015 Jul 18, Jan Tunér commented:
In the paper by Kucuk, a laser of 250 mW was used for 48 seconds. This produces energy of 12 J. This parameter is not reported, only the dose of 12 J/cm2. Since the laser aperture is reported to deliver a spot of approximately 10 mm, the dose and the energy in this case gets almost the same numeric value. So far so good. The problem is the understanding of the therapeutic window for biostimulation. The authors cite other researchers and here the complications start. For instance, Hansson used 904 nm, 0.3 mW, 3 minutes. 0.3 x 180 = 0.054 J for clinical use. Mazetto used 780 nm, 70 mW, 10 s, 89.7 J/cm2 = 0.7 J for clinical use. Venanzio used 780 nm, 30 mW, 10 s, 6.3 J/cm2 at three TMJ points. 0.3 x 3 = 0.9 J. The energies in these studies have had to be recalculated since they are not reported in the papers. The three examples above are for TMD arthritic pain. The myalgic studies discussed in the Kucuk paper have the same problem. Now, looking at the energies used in the three studies above, these have been in the range 0.5 - 0.9 J per point. For an average human (keeping in mind that TMD appears to be more common in females) of 60 kg, this would mean approximately 0.2 J per kg. The mean weight of the rabbits was about 3 kg. The 12 joules applied brings 4 joules per kg. For humans this corresponds to 4 x 60 = 180 J! The Arndt-Schultz law stipulates that “For every substance, small doses stimulate, moderate doses inhibit, large doses kill.” The exact optimum for biostimulation of inflammation in the TMJ is not known, but the World Association for Laser Therapy recommends 1-2 points and a total energy of 4 J for clinical use. The TMJ is quite superficial whereas muscles require considerable higher energies due to the poor penetration into these well vasculated tissues. The power density (mW/cm2) is also of importance and low power and longer time are reported to be more effective for tissue repair than high power and short time, even using the same total energy. It is suggested that the lack of effect in the Kucuk paper is due to gross over dosage and subsequent inhibition.
This comment, imported by Hypothesis from PubMed Commons, is licensed under CC BY.
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- Feb 2018
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www.ncbi.nlm.nih.gov www.ncbi.nlm.nih.gov
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On 2015 Jul 18, Jan Tunér commented:
In the paper by Kucuk, a laser of 250 mW was used for 48 seconds. This produces energy of 12 J. This parameter is not reported, only the dose of 12 J/cm2. Since the laser aperture is reported to deliver a spot of approximately 10 mm, the dose and the energy in this case gets almost the same numeric value. So far so good. The problem is the understanding of the therapeutic window for biostimulation. The authors cite other researchers and here the complications start. For instance, Hansson used 904 nm, 0.3 mW, 3 minutes. 0.3 x 180 = 0.054 J for clinical use. Mazetto used 780 nm, 70 mW, 10 s, 89.7 J/cm2 = 0.7 J for clinical use. Venanzio used 780 nm, 30 mW, 10 s, 6.3 J/cm2 at three TMJ points. 0.3 x 3 = 0.9 J. The energies in these studies have had to be recalculated since they are not reported in the papers. The three examples above are for TMD arthritic pain. The myalgic studies discussed in the Kucuk paper have the same problem. Now, looking at the energies used in the three studies above, these have been in the range 0.5 - 0.9 J per point. For an average human (keeping in mind that TMD appears to be more common in females) of 60 kg, this would mean approximately 0.2 J per kg. The mean weight of the rabbits was about 3 kg. The 12 joules applied brings 4 joules per kg. For humans this corresponds to 4 x 60 = 180 J! The Arndt-Schultz law stipulates that “For every substance, small doses stimulate, moderate doses inhibit, large doses kill.” The exact optimum for biostimulation of inflammation in the TMJ is not known, but the World Association for Laser Therapy recommends 1-2 points and a total energy of 4 J for clinical use. The TMJ is quite superficial whereas muscles require considerable higher energies due to the poor penetration into these well vasculated tissues. The power density (mW/cm2) is also of importance and low power and longer time are reported to be more effective for tissue repair than high power and short time, even using the same total energy. It is suggested that the lack of effect in the Kucuk paper is due to gross over dosage and subsequent inhibition.
This comment, imported by Hypothesis from PubMed Commons, is licensed under CC BY.
-