OK, this might sound like a silly questions, but are they reliable for long span bridges? all on 4 implants? a colleague of mine insists that they are not reliable for these purposes .. he says he tried one and it is reliable only for short span bridges or single crowns, he says adjustments have to be made almost all the time because of mis-fittings. One other thing, could you recommend an IO scanner which outputs .STL that does not obligate you to pay annual fees!!!??.