Screens are perfectly safe at the temps involved. I blame Arizer as much as anyone else for perpetuating these myths. He's always used 'scare tactic' advertising. He's not the only one either.
"Others use metals, plastics, Teflon, aluminum and even wood in their construction or parts which can give off harmful toxins, bad taste and a poor experience."
I believe he used that same line in his original V-Tower advertising on eBay.
"Ceramic is used so there is no concern of toxins or bad tastes as there can be from metal heaters."
Manufacturers went to ceramic heaters for longevity, not safety. Vapor Brothers was one of the last brand name vapes to move from metal to a ceramic heating element, and they'd have you believe that theirs is the only safe ceramic element.
"Vapor Brothers is proud to announce our NATURAL MINERAL HEATER is the first truly safe ceramic heating element for use in vaporizers, and only available in Vaporbrothers Vaporizers. We've carefully designed our heater to be free of Aluminum, plastic, or dirty industrial materials."
http://www.vaporbrothers.com/
VB would also like you to believe they have a lifetime warranty, but warranty means free repair and theirs only covers 2 yrs.
"You will get 2 years of free repair from the purchase date, and don't have to provide proof of purchase to take advantage of our warranty. Beyond 2 years, there is a flat fee for warranty repair which is currently $35. There are extra shipping charges if you live outside the continental US."
I can pick on the maker of my beloved SSV too.
"The heating element is actually encased in a ceramic coating. This provides a longer service life than the conventional nichrome-iron wire elements that are exposed to the air. The heating element does not become oxidized then corrode, deteriorate and burn out in only a few months."
http://www.silversurfervap.com/herbalvaporizerinformation.htm
(On their 'compare' page they also say the Vapezilla, Evolutions, and Vapolution housings get "really hot" during use. Not true at all. In fact, the Vapolution housing barely gets warm.)
The Vapolution happens to use a wire heater that's wrapped around the outside of the glass heating chamber. If it burned out in a few months due to oxidation, corrosion, etc., they would gone out of business long ago. Mine's been going for over 2 yrs. now. So even a metal element can be long lived, depending on the design. The Vapo guys aren't above BS either. They advertise a lifetime warranty against manufacturer defects, yet they charge either $25 or $50 for any repairs after 90 days.
Bottom line-don't believe everything you read concerning the vapor industry. You've got to sift through a lot of advertising that says the other guys make vapes that are crappy and/or dangerous, not to mention myths floating around forums.
To be fair, there are manufacturers that don't point fingers at others in their advertising, and they're to be applauded IMO.