Do the values listed above (1 chest X-ray = 4 dental X-rays) apply to digital or analog X-rays? Below it says that the values for digital imaging are another 10 times lower, so 1 conventional chest X-ray = 40 digital dental X-rays?

The received doses in digital radiology are approximately ten times lower. The reason is the much greater sensitivity of the digital sensor to X-rays. Because of this higher sensitivity, the object being imaged (the tooth) can be exposed to a lower dose of radiation. The harmful effect on the irradiated organ is therefore considerably lower and the procedure less risky. Nevertheless, the rule should be followed that every X-ray must be professionally justified, because the doses received by patients and therapists during X-ray imaging accumulate throughout life.