citations and such
someone asked about citations for my last post, and I have to admit, there aren't that many. Here's what I wrote back to them, in case you want to see my thought process as well. Now that I've calmed down from my initial frustration, I do admit - any barrier is better than no barrier. But that's a pretty large gray area of risk, really.
When I first looked this up online, I used: this source as a launching point because it was cited and seemed well-researched.
However, I also remembered Harold McGee using various forms of plastic food wrap in persimmon-ripening experiments in one of his culinary books, so I consulted that, which led me to 1) Wikipedia for various types of plastic wrap materials, and 2) two journals: Polymer and The Journal of Food Science (but I don't have the citations today..... I'll see if I can dig them up). Those gave me ideas on the porosity and thickness of various materials, which turns out to be related to the standards to which a particular polymer is made (logical, but it hadn't occurred to me). Polyvinylidene chloride (the original) is really quite impermeable, and if you can find someone who still makes it (perhaps a lab source), you could get a rather large roll of it and tear it off to size. I've heard from fellow cooks that "freeze-tite" a product by the makers of "stretch-tite" is "almost as good as the old saran," but that's for freezing cakes, not safe sex, so I can't make any claims other than food preservation.
LD polyethylene is far more permeable to water and other molecules (did you ever do the science experiment where you took different brands and put them over glasses of water for a week? anyway.....). Moreover, while it's a "good-fair" resistor to oil-induced breakdown, it's not completely resistant (nor is latex, admittedly). (citation).
A search of PubMed, as well as UpToDate, Micromedix, and MD Consult yielded nothing. I won't go off on a tangent about the paucity of studies on non-procreative sexual health.
So, the herpesviridae are 150 nm in size, approximately, retroviruses are about 120 nm, and HPV is tiny, at around 50 nm (citation, though any virology book could also be used). As the straight dope pointed out in the '90s, latex gloves are not made to the same standards as condoms, which makes condoms inherently safer than gloves. Why then, do we even bother saying "cut up a glove to be a dental dam?" Well, honestly, now that I've seen that, I'm not sure. I haven't looked any further into the matter, however. At least, not yet.
Okay, so a water molecule is about 0.01 nm (Wiki), which is clearly much smaller than HSV. So even if a plastic film isn't water-tight, it might still be virus-tight. True. And I don't know the size of most onion odor particles (dipropyl disulfide is still pretty small, but I don't know others), so I can't guess as to how they relate to viral particles, though I imagine it's along the same lines as water.
So I've seemingly just disarmed my own argument, right? Well, maybe. Here's my main problem: manufacturing standards. Just as latex gloves aren't held to the same standards as condoms, plastic film wraps are held to even less of a standard. Moreover, they're thinner material than condoms (or gloves). There isn't any available information that I can find related to the specific quality measures of food wrap, but I very much doubt it's as regulated as something manufactured specifically for the prevention of fertilization/STI transmission. I can't imagine SC Johnson would tell me, if they even have data, on the number of microtears per square foot they find acceptable. I have no citations for that, nor do I think any are available. Until the study is done, I feel it is important for me to not lead my patients into a possibly false sense of security. If I had a lab, I'd do the study myself. Maybe someday.....
To be fair, the odds of transmitting most viruses during oral sex are relatively small (unless you're actively shedding HSV). But HSV I infections of formerly HSV II-only territory are definitely on the rise. I have only seen one picture of a possible HPV infection on someone's oral mucosa obtained from a partner, and I don't know if that'll pan out as anything significant. To that end, any barrier is better than no barrier. And odds are that food wrap is probably good enough for most people. I don't know if that's something I should ever say to my patients. The odds may be acceptable for you, in which case, that's your decision. But I do object to putting the line "saran wrap is totally safe!" out there without the caveat that "we don't know that with any sort of proof."
When I first looked this up online, I used: this source as a launching point because it was cited and seemed well-researched.
However, I also remembered Harold McGee using various forms of plastic food wrap in persimmon-ripening experiments in one of his culinary books, so I consulted that, which led me to 1) Wikipedia for various types of plastic wrap materials, and 2) two journals: Polymer and The Journal of Food Science (but I don't have the citations today..... I'll see if I can dig them up). Those gave me ideas on the porosity and thickness of various materials, which turns out to be related to the standards to which a particular polymer is made (logical, but it hadn't occurred to me). Polyvinylidene chloride (the original) is really quite impermeable, and if you can find someone who still makes it (perhaps a lab source), you could get a rather large roll of it and tear it off to size. I've heard from fellow cooks that "freeze-tite" a product by the makers of "stretch-tite" is "almost as good as the old saran," but that's for freezing cakes, not safe sex, so I can't make any claims other than food preservation.
LD polyethylene is far more permeable to water and other molecules (did you ever do the science experiment where you took different brands and put them over glasses of water for a week? anyway.....). Moreover, while it's a "good-fair" resistor to oil-induced breakdown, it's not completely resistant (nor is latex, admittedly). (citation).
A search of PubMed, as well as UpToDate, Micromedix, and MD Consult yielded nothing. I won't go off on a tangent about the paucity of studies on non-procreative sexual health.
So, the herpesviridae are 150 nm in size, approximately, retroviruses are about 120 nm, and HPV is tiny, at around 50 nm (citation, though any virology book could also be used). As the straight dope pointed out in the '90s, latex gloves are not made to the same standards as condoms, which makes condoms inherently safer than gloves. Why then, do we even bother saying "cut up a glove to be a dental dam?" Well, honestly, now that I've seen that, I'm not sure. I haven't looked any further into the matter, however. At least, not yet.
Okay, so a water molecule is about 0.01 nm (Wiki), which is clearly much smaller than HSV. So even if a plastic film isn't water-tight, it might still be virus-tight. True. And I don't know the size of most onion odor particles (dipropyl disulfide is still pretty small, but I don't know others), so I can't guess as to how they relate to viral particles, though I imagine it's along the same lines as water.
So I've seemingly just disarmed my own argument, right? Well, maybe. Here's my main problem: manufacturing standards. Just as latex gloves aren't held to the same standards as condoms, plastic film wraps are held to even less of a standard. Moreover, they're thinner material than condoms (or gloves). There isn't any available information that I can find related to the specific quality measures of food wrap, but I very much doubt it's as regulated as something manufactured specifically for the prevention of fertilization/STI transmission. I can't imagine SC Johnson would tell me, if they even have data, on the number of microtears per square foot they find acceptable. I have no citations for that, nor do I think any are available. Until the study is done, I feel it is important for me to not lead my patients into a possibly false sense of security. If I had a lab, I'd do the study myself. Maybe someday.....
To be fair, the odds of transmitting most viruses during oral sex are relatively small (unless you're actively shedding HSV). But HSV I infections of formerly HSV II-only territory are definitely on the rise. I have only seen one picture of a possible HPV infection on someone's oral mucosa obtained from a partner, and I don't know if that'll pan out as anything significant. To that end, any barrier is better than no barrier. And odds are that food wrap is probably good enough for most people. I don't know if that's something I should ever say to my patients. The odds may be acceptable for you, in which case, that's your decision. But I do object to putting the line "saran wrap is totally safe!" out there without the caveat that "we don't know that with any sort of proof."