There have been a LOT of e mails coming through over the last few weeks on this topic and I am encouraging people of access and join in with this discussion (whether related to animal or human based therapy)
At the end of the day, there are a lot of claims that Class 4 lasers are 'better' than the more commonly employed Class 3(b) units. They apparently (a) deliver more energy and (b) the light goes deeper into the tissues.
Delivering more energy (or the same energy in less time) I can see - though I am not sure I can see the clinical advantage other than reducing the treatment time - which is not especially long in any case. We have substantial evidence re the amount of energy needed for clinical efficacy - does not say that this is dependent on which type of laser is used to deliver - it says how much energy (or energy density or fluence or . . . .) is needed
As for the increased penetration, I struggle with this one. We know that laser penetration (the % of light reaching tissue depth X) depends on several things - wavelength being one of them. If using light of wavelength YY nm penetrates into the tissue such that ZZ% of that light reaches 1cm depth, then this does not change by increasing the power of the laser - surely?? The same % reaches the 1cm depth. The actual amount of energy will be different, but the % remains the same - though I stand to be corrected by those who know laser better than I do
IF there is a clinical advantage (I know about the cell studies & animal/tissue models) than I would just love to know about them - as would many readers and users of this Forum - please contribute