Not sure what to make of this, thus far.
Had my teeth cleaned and got a new question -- do you vape?
Uh, no, I don't -- and I asked why the question.
Apparently at least in my local dentist's practice they've started to see an alarming pattern. It's not yet established as causative, but they noted it and thus now are asking all their customers about vape use.
The pattern is, as was described to me, similar to that seen in people who smoke meth -- of the same general form but less-severe, specifically concentrated at and below the gumline.
Tweakers have been long-identified on a trivial basis due to the severe impact it has on their teeth, with them literally rotting out of their head at very young ages. The reason is that the chemicals in meth, when smoked, results in an extremely high acid content level that concentrates at the gumline where it's not flushed out rapidly by saliva.
You'd think there wouldn't be a similar issue with vapes since there's no acid involved.
Or is there?
There is some literature on heat-based decomposition of both of the common carrier fluids in the literature. Of course glycerol and propylene glycol have been used in various cosmetic and hygiene products (specifically, toothpaste and various skin preparations) for a long time and are generally regarded as safe. But that something is safe when swished around the mouth, put on the skin or even eaten in modest amounts doesn't mean heating and vaporizing it is safe.
Interestingly enough these fluids are also used as the common element in commercial fog machines (e.g. for stage shows, etc) and nobody raises issues there either. But here the exposure is diluted by volume and, in addition, is for a relatively short period of time. Nonetheless I am aware of no restriction on their use in this fashion, which you would think would have pointed to trouble if it existed before now.
Or maybe not.
There's an interesting and confounding factor here -- many vape setups offer variable power levels -- and thus temperature. The exact level of control (or lack thereof) in these systems is subject to plenty of debate; I've not looked at them all that closely such as, for example, by disassembling one and analyzing the circuitry inside. It certainly is possible to design a vaporizing system with a thermal mass sufficient to buffer the heating output and then place it under PID control so as to obtain a highly-repeatable and calibrated temperature to vaporize the liquid, but I'm willing to bet that most -- if not all -- such devices in common use have none of this sort of sophistication in them, being either variable voltage or variable-current output devices and inferring temperature where that appears to be an option -- those are a lot easier and cheaper to design.
Commercial PID controllers for other applications (e.g. an espresso machine) are available but aren't exactly $20 devices -- and for that reason I highly doubt that such a device plus the power source plus packaging is showing up in these units.
But it may need to -- because if dental practices are seeing severe tooth damage from these devices then it's entirely possible that it's a function of the temperature of operation and thus the reaction products responsible -- not so much the material itself.
This may -- and I repeat may -- tie into the "vape lung" problems. If it does that would also render trying to isolate a particular substance and source nearly impossible since it would then be the combination of the particular juice or "fill" material used plus the unit in question and its power setting that results in the problem. Remove any of those and the problem doesn't occur because the dangerous reaction product isn't formed at all, or isn't formed in a sufficient concentration to cause trouble.
All-in this looks interesting. I've found some research papers on the topic and am going to spend time studying them in detail; fortunately I have a reasonable understanding of the chemistry involved (heh, what do you know, those chem classes were useful after all!) and thus, in a follow-up column, if I find anything that looks like a "smoking vape pipe" I'll point it out.
In the meantime, however, it certainly would appear that using the lowest power level consistent with getting output from the unit you have, if you're using one with variable power output, is a good idea. If you're not using one with variable output you want to change that -- and turn the thing all the way down. If you have to take two "hits" to get the nicotine you want instead of one due to the lower power level, but those two hits deliver an effective zero of the harmful components that are causing problems where the higher power level does produce some you're definitely ahead of the game -- and I can conceive of no rational basis from a chemistry point of view to believe that fewer harmful byproducts are produced through higher power level settings.
In other words, whether you're vaping tobacco or marijuana: Turn the power level down as far as you can and still receive some level of output -- use it more-often or take a longer "hit" to get whatever dose you seek rather than increasing the power. If you have a unit with temperature control -- they appear to be available but most units are not temperature-calibrated (they're "power" or "voltage" settable instead), never mind that I wouldn't trust the accuracy of indirect measurement by coil resistance, as it appears everyone is doing -- set it as low as is practical to obtain output.