The goal of dental radiography is to obtain diagnostic information while keeping the exposure to the patient and dental staff at minimum levels. We know that x-rays, in sufficient doses, may produce harmful effects in human beings. However, we do not know the size of the risk (or even if there is any risk at all) from small doses of x-rays, such as those used in dental radiography.
It is the consensus of dental radiologists that the dosage from dental x-ray exposure is not harmful. However, the absence of conclusive proof that establishes the absence of risk means we must assume that there is the potential of some risk from diagnostic exposure.