This isn't necessarily a repair article, although there might be several nuggets on info for getting your Dental-Eye (v1) repaired. It's a commented and illustrated guide to removing, adapting, and rewiring - to an external flash - the entire 50mm macro lens assembly from the original Dental-Eye. There is an update section with improvements, and several links to other articles in later postings on adapting other Dental-Eye versions too... www.dpreview.com/forums/thread/4274131
Maybe I'm looking in the wrong place, but I don't see the 50mm Dental on the lens list.
All three versions of the Dental-Eye's are fixed lens mount cameras (like this Dental-Eye v.1), and the lenses are (semi)permanent... so there are no standalone dental lenses. Each one of the three models can be cannibalized to remove the lens/flash assembly and by using some creative mounting techniques, they can be adapted for digital use. They're more complex than using something like 35mm slide projector lenses in helicals or macro tubes, and especially if one wants to use the ring flash - so it does take a bit of extra work to get something truly usable.
on youtube or elsewhere is a deep instruction to make dentaleye digital Canon EF-ready. 100mm?
Just like the original link I posted to start this topic, I've seen several more articles and a few videos on adaptations of both the dental 50mm and 100mm lenses - however - I don't recall any of them being complete conversions in the traditional sense. The aperture/iris is physically connected to the focus function internally, so turning the grip to focus the lens will adjust the aperture, whether you want it to or not. The stand-alone Medical DX 100mm operates in the exact same way, even if it doesn't need a mount conversion to adapt it to a body. Pulling these semi-attached dental lenses severs the linkage, if I remember correctly, so without any aperture ring to adjust with, there are advanced operating issues beyond just forming a working mount system.
Higher magnification macro lenses like these can introduce a greater amount of diffraction errors, and I presume the focus+aperture adjustments were designed to lessen or eliminate that, as well as guarantee a reasonable amount of margin for depth of field. Keep in mind that the dental and medical lenses weren't intended for use in the hands of knowledgeable photographers, and their users wouldn't necessarily know the difference between an f-stop and a truck stop, so they were meant to be 'fool proof' for the science crowd.
If there's any intention of using the ring flash or modeling light, those require additional modifications. I've seen several articles that address those issues too, but, adapting flash tubes and potentially frying sensitive digital gear from their high voltage discharges are obviously risky things to try.
If someone wants a 50mm or 100mm macro to adapt, these might be more work than they're worth - unless - you get more joy in tinkering than shooting photos. Finding a clean and working 105mm Kiron/Keno or Lester Dine Macro might be a better alternative, and a lot less work to adapt it. If a Yashica is prefered, then the Yashinon/Mamiya/Tomioka 60mm Macro in M42 mount would be another option, at a higher price point.