The conflict of interest problem could be significantly reduced by having a third party read the x-rays (i.e. make the interpretation of dental radiographs a radiology subspecialty or create a subspecialty within dentistry for doing this). This wouldn't have been very practical in the old days of film-based radiography, but with digital technology you could easily transmit all the images to a third party for reading. Having a dedicated specialist reading the x-rays would both address the conflict of interest problem (the specialist has no incentive to be biased; they'd get paid a flat fee to read the images and generate a report) and would very likely also improve the accuracy of cavity detection because the images would be read by someone who reads way more dental x-rays per day than any individual dentist ever would.