Introduction:
According to research, several studies have demonstrated and suggested that if a response to diagnostic radiation exists, during the late second trimester, the main issue, though rare, would be the potential possibility of malignant disease or neoplastic changes during childhood or infancy. However, such a response to radiation during pregnancy results from a very high dose exposure. Approximately 5% of live births may involve a congenital abnormality even without any high-dose radiographic exposure. It is also estimated that there is a potential one percent increase in congenital abnormalities if the pregnant patient gets exposed to a dose of more than 10 rads, which equals 100 mGy of fetal dose. As the fact is clear that diagnostic doses are much less than 10 rads in dentistry, such abnormalities cannot be attributed to dental diagnostic doses of x-ray exposure.
According to the American Academy of Family Physicians (AAFP), dental x-rays are generally safe during pregnancy. Still, controversy is generally prevalent in the literature surrounding this issue due to radiation exposure's elusive results. Hence, after studying the high radiation exposure in pregnancy, such x-rays are not recommended. Even normal dental x-rays with limited diagnostic exposure should only be done when the benefits outweigh the risks.
When Is Radiation Exposure Harmful?
The evidence is that if a biological response occurs to radiation, it only happens during the first two weeks of pregnancy, which is a sensitive period when the mother is unaware of her pregnancy. Hence this time period is more sensitive to the biological response that can lead to potential miscarriage of the fetus.
Research shows that spontaneous abortion due to radiation during the first two weeks of pregnancy at doses less than 25 rads (250 mGy) is highly improbable, and no hypothesis exists to show that radiation exposure can cause abortions. Generally, as a preventive measure, to limit the amount of radiation for safety concerns, no radiography procedure is usually carried out on pregnant women unless there remains an absolute necessity for high-grade dental conditions or neoplasms that warrant immediate investigation.
What Are the Precautions for Limiting Exposure?
The radiologist should follow the precautions necessary to minimize the absorbed dose of radiation. These techniques should be undertaken when dental radiography is indeed mandatory for that case. Radiographs are to be provided with well-collimated beams and specifically in precisely-protected shields. A high-kVp technique by the dentist or radiographer is appropriate in such cases.
Pregnant women can definitely receive dental treatment, especially in the second trimester, where periodontal and gingival disease are high-risk factors for preterm birth and low-weight infants, apart from dental disease's potential to induce maternal body infections. Hence the dentist should consider the above-mentioned principles and rule out the possibility of carrying out radiographic techniques during pregnancy unless absolutely indicated in serious cases. This can be done in high-risk patients by observing protective measures and by patient awareness of the same by an explanation about the safest period for radiography and the radiation doses involved in dental diagnostic procedures.
According to clinical research, lead aprons have been shown to reduce radiation doses to gonads up to 98%. Similarly, in a pregnant woman, due to the maternal tissues that cover the fetus, the fetal dose is reduced by nearly 30% as compared to the abdominal skin dose. The use of an apron with lead shielding and even a thyroid shield can be used to mainly reduce the total risk of radiation dose to the fetus. Shielding is a technique-sensitive procedure that should be done with proper care. The radiograph should be of adequate diagnostic quality and should be outside the arena of the x-ray beam. Hence this can be of added advantage to prevent overexposure or limit the exposure to an extent.
Widespread fears of radiation can threaten the mother's well-being psychologically because of the potential damage that would be caused to their unborn infant. Hence mental counseling is absolutely indicated in cases for dental radiography. For high-risk conditions, it is essential to alleviate the fear and anxiety level of the expecting mother. Also, it would be reasonable to counsel the pregnant woman and their family on the different levels of radiation exposure and associated risks while or before performing the radiologic procedure. It is preferable for radiographic departments to have pregnancy warning signs in the waiting rooms for patient education and caution.
Why Is Diagnostic Radiation Not Harmful?
Evidential documentation has shown that diagnostic radiation doses in dentistry neither result in developmental anomalies nor mental retardation in the fetus. Diagnostic doses result in no developmental or mental problems in the fetus. Also, no evidential reports exist to suggest if developmental anomalies or mental retardation in fetuses occurs after exposure to diagnostic radiation doses in pregnancy. Regardless of the effect of genetics or hereditary traits, by the individual exposure to diagnostic radiation of intra-oral techniques in dentistry, the incidence of neoplasms occurring is extremely rare, only upto 0.2% as studied by researchers.
The observations in clinical trials conducted on pregnant women have shown that the period in which the fetus is the most sensitive to radiation is during the first trimester only. Research suggests that the first trimester remains a delicate and sensitive period during pregnancy. This is because of the exposure threshold for the development of defects during and post the organogenesis period of the developing fetus. Dental and maxillofacial surgeons always have a professional level of awareness regarding both the principles of diagnostic radiation in dentistry and protection from radiation. Dentists are also aware by virtue of training and education about the role of diagnostic radiation in absolutely indicated cases; however, the dentist should also maintain precautions to prevent high doses of exposure in these unavoidable circumstances when an oral or dental emergency warrants radiography.
The fetal dose from a dental x-ray examination is inclusive of the preferred modality for diagnosing dental cysts, oral neoplasms, and deep infections of the jaw or the maxillary sinus through computed beam tomography. In this procedure of CBCT, the dose is estimated to be approximately between 0.009 μSv and 7.97 μSv (which is evidentially negligible in terms of radiographic exposure to the fetus). Also, the cancer risk to the fetus is very rarely possible when the fetal dose is more or nearer to 10uSv.
Conclusion:
To conclude, the risk to the fetus from a few µSv of radiation in dentistry as per traditional clinical research is extremely small or rare. Hence patient doses in the normal practice of dental radiology or dentistry would never pose a risk close enough to warrant consideration of termination. Patient education and counseling regarding the importance of dental treatment in pregnancy and maintenance of oral hygiene along with prevention of exposure to dental x-rays to the pregnant patient until necessitated remains crucial to the health of the fetus.