Radiation exposure to foetus and breasts from dental X-ray examinations: effect of lead shields

Radiation safety of dentomaxillofacial radiology in Finland: Reported abnormal irradiation-related incidents during 2012-2022

INTRODUCTION

This study evaluates adverse events (AEs) in dentomaxillofacial radiology (DMFR) in Finland, including their quantity, nature, and outcomes. It also compares reporting activity between public and private healthcare organizations, as they share same legal obligations to report AEs. Two-thirds of dental images are taken in public, the rest in private healthcare.

METHODS

In Finland, radiation-related AEs are reported to the Radiation and Nuclear Safety Authority (STUK). We categorized DMFR-related AEs by nature, outcome, and imaging modality. We also submitted a questionnaire to STUK to gather information on their observations and remarks made during inspections of establishments providing dental imaging services.

RESULTS

During 2012-2022, STUK received reports of 1343 DMFR-related AEs, mostly causing patient harm (92.9%) leading almost always to excessive radiation doses (99.7%). Private healthcare reported most AEs (65.2%), with municipal institutions reporting the remainder (34.8%). Intraoral-related AEs (20.0%) slightly outnumbered panoramic-related ones (18.7%), but the majority (56.7%) didn't specify the imaging modality. CBCT-related incidents were least reported (4.5%). During STUK's inspections, remarks mostly concerned deficiencies in practical quality assurance (31.3%) or technical quality assurance (32.9%).

CONCLUSION

DMFR-related AEs may be underreported despite legal obligations, with most stemming from human error, highlighting the need to enhance patient safety culture. There's a notable reporting gap between private and public healthcare providers relative to the number of dental radiographs conducted. Organizational deficiencies in practical and technical quality assurance underscore the importance of ongoing education, as well as monitoring by STUK.

IMPLICATIONS FOR PRACTICE

Enhancing patient safety culture in dentistry, including dentomaxillofacial radiology, demands customized multiprofessional development, as unaltered patient safety procedures from medicine and secondary care may not align with dentistry's requirements.

Determination of relative dose of ionizing radiation in the thyroid gland using a panoramic device with different protocols

BACKGROUND

The use of panoramic radiography (PR) is a complementary examination to aid in the diagnosis of cases in paediatric dentistry. The lack of specific protocols for these devices, however, can result in high doses of radiation, affecting critical organs such as the thyroid.

AIM

To evaluate the discrepancies in ionizing radiation received by the thyroid during PR examinations using anthropomorphic paediatric simulators built from computed tomography images.

DESIGN

Two anthropomorphic paediatric phantoms were printed and used, representing children aged 6 and 11 years, with an opening in the thyroid region for the insertion of dosimetric radiographic films. The simulators were subjected to different pre-existing protocols in the PR devices. The radiographic films were processed and analysed using a luxmeter.

RESULTS

The radiation dose to the thyroid was higher in the 6-year-old phantom than in the 11-year-old phantom, for given exposure factors. In addition, there was an increase in dose in children's protocols compared with small adult protocols.

CONCLUSION

Therefore, companies that develop PR equipment must develop child protocols for separate age groups that will consequently reduce the radiation dose in children, especially in their critical organs.

Impact of dental imaging on pregnant women and recommendations for fetal radiation safety: A systematic review

Purpose

This study was conducted to investigate the safety of dental imaging in pregnant women with respect to fetal health.

Materials and Methods

Searches were conducted of the PubMed, Scopus, and Web of Science databases in May 2023. The inclusion criteria encompassed cross-sectional and longitudinal studies that focused on the analysis of diagnostic dental imaging in pregnant women, as well as studies utilizing phantoms to simulate imaging examinations. The exclusion criteria consisted of reviews, letters to the editor, book chapters, and abstracts from scientific conferences and seminars.

Results

A total of 3,913 articles were identified. Based on a review of the titles and abstracts, 3,892 articles were excluded, leaving 21 articles remaining for full-text review. Of these, 18 were excluded, and 4 additional articles were included as cross-references. Ultimately, 7 articles underwent quantitative-qualitative analysis. Three retrospective studies were focused on pregnant women who underwent dental imaging procedures. The remaining 4 studies utilized female phantoms to simulate imaging examinations and represent the radiation doses absorbed by the uterus or thyroid.

Conclusion

Few dental radiology studies have been conducted to determine the safe radiation threshold for pregnant women. Additionally, the reviewed articles did not provide numbers of dental examinations, by type, corresponding to this dose. Dental imaging examinations of pregnant women should not be restricted if clinically indicated. Ultimately, practitioners must be able to justify the examination and should adhere to the "as low as diagnostically acceptable, being indication-oriented and patient-specific" (ALADAIP) principle of radioprotection.

Latest Concepts in Endodontic Management of Pregnant Patients

Pregnant patients and how to manage their treatments is one of the most important challenges in endodontic practice. Endodontic treatment on pregnant women is sometimes an emergency condition to control toothache due to irreversible pulpitis and odontogenic infection. Tooth decay, oral health, local and general anesthesia, analgesics, antibiotic prescription, drug interactions, and X-ray radiation are the most important considerations that may impact treatment planning and endodontic practice in pregnancy. The aim of this article is to notify and explain the latest concepts in the endodontic management of pregnant patients.

Patient shielding during dentomaxillofacial radiography: Recommendations from the American Academy of Oral and Maxillofacial Radiology

BACKGROUND

The American Academy of Oral and Maxillofacial Radiology established an ad hoc committee to draft evidence-based recommendations and clinical guidance for the application of patient contact shielding during dentomaxillofacial imaging.

TYPES OF STUDIES REVIEWED

The committee reviewed monographs and reports from radiation protection organizations and studies that reported radiation dose to gonads, breasts, and thyroid gland from dentomaxillofacial imaging.

RESULTS

Considering the absence of radiation-induced heritable effects in humans and the negligible dose to the gonads and fetus from dentomaxillofacial imaging, the committee recommends discontinuing shielding of the gonads, pelvic structures, and fetuses during all dentomaxillofacial radiographic imaging procedures. On the basis of radiation doses from contemporaneous maxillofacial imaging, the committee considered that the risks from thyroid cancer are negligible and recommends that thyroid shielding not be used during intraoral, panoramic, cephalometric, and cone-beam computed tomographic imaging.

PRACTICAL IMPLICATIONS

This position statement informs and educates the reader on evolving radiation protection practices and provides simple, unequivocal guidance to dental personnel to implement these guidelines. State and local authorities should be contacted to update regulations to reflect these recommendations.

Evaluation of the radiation protection effectiveness of a lead-free homopolymer in cone beam computed tomography

OBJECTIVE

The objective was to compare the radiation protection effectiveness of a lead-free thermoplastic homopolymer (Anti-RAD) to conventional lead shielding in cone beam computed tomography (CBCT) exposures.

STUDY DESIGN

Thermoluminescent dosimeters were placed on a human bone- and soft tissue-equivalent phantom to record equivalent doses in the thyroid gland, thyroid skin, and breast areas. CBCT images were obtained with the following 3 protocols: (1) without radiation shielding; (2) with 0.5-mm lead equivalent lead-containing shielding; and (3) with 0.5-mm lead equivalent Anti-RAD shielding. Independent t tests were used to evaluate the results.

RESULTS

Compared with exposures without shielding, both lead and Anti-RAD protective devices reduced thyroid gland equivalent doses by approximately 40%, thyroid skin doses by approximately 75%, right breast skin doses by approximately 80%, and left breast skin doses by 75%. The differences in equivalent dose for both types of shielding compared with exposure with no shielding were statistically significant (P ≤ .042). However, there were no significant differences in dose reduction at any site between lead and Anti-RAD shielding (P ≥ .135).

CONCLUSIONS

Radiation protection equivalent to lead can be provided with the Anti-RAD shield. With the use of this material, disadvantages such as damage to the aprons, lead toxicity, weight of lead aprons, and microbial contamination can be reduced.

Knowledge, attitudes and practices of undergraduate students and dentists about dental prenatal care

INTRODUCTION

Prenatal care is a fundamental moment for health promotion to be carried out, since at that moment women are more receptive to new knowledge, with the aim of providing better healthcare for the baby. This study aimed to evaluate the knowledge, attitudes and practices of undergraduate students and professionals, both from the public and from private sectors in Brazil, regarding dental prenatal care.

MATERIALS AND METHODS

This study corresponded to an online questionnaire survey, via Google Forms, consisting of 17 general questions for undergraduates (n = 103) and 16 for professionals (n = 227) for demographic and school mapping, and 18 specific questions about the importance and protocol of dental prenatal care. T-test, Mann-Whitney U-test and multiple linear regression were adopted (p < .05).

RESULTS

The average total score of the questionnaire for students and professionals was 12.40 and 15.65, respectively (p < .0001), indicating moderate knowledge. Professionals showed a higher prevalence of moderate (77%) and high (2%) knowledge of the subject when compared to undergraduate students (51% and 0% respectively). The graduation period in which the students were enrolled was a predictor of the total score of the questionnaire [F (1, 101) = 21.21; p < .0001; R²  = .165]. The female gender and the lower weekly workload were the main predictors of the total score of the questionnaire for professionals [F (3, 223) = 6.74; p < .0001; R²  = .083].

CONCLUSIONS

Although professionals have greater knowledge about dental prenatal care than students, there are still deficiencies in the knowledge and practices of them in respect of dental management during pregnancy. Higher education institutions need to change the teaching-learning plan regarding the holistic dental approach for women during pregnancy.

EFFECT OF PELVIC LEAD SHIELD ON ORGAN DOSES IN POSTERO-ANTERIOR CHEST RADIOGRAPHY

Lead shields are commonly used in X-ray imaging to protect radiosensitive organs and to minimise patient's radiation dose. However, they might also complicate or interfere with the examination, and even decrease the diagnostic value if they are positioned incorrectly. In this study, the radiation dose effect of waist half-apron lead shield was examined via Monte Carlo simulations of postero-anterior (PA) chest radiography examinations using a female anthropomorphic phantom. Relevant organs for dose determination were lungs, breasts, liver, kidneys and uterus. The organ dose reductions varied depending on shield position and organ but were negligible for properly positioned shields. The shield that had the largest effective dose reduction (9%) was partly positioned inside the field of view, which should not be done in practice. Dose reduction was practically 0% for properly positioned shields. Therefore, the use of lead shield in the pelvic region during chest PA examinations should be discontinued.

[Radiation dose permitted in dentistry patients. A review]

In dental practice, the use of imaging has increased over the years, generating an increase in the radiation dose for the dental patient. One factor under discussion is the amount of dose used in patients, men, women and children, at different stages of their life, due to the scientific evidence of the harmful effects of ionizing radiation. This review of the literature analyzed the characteristics of radiation and its effects in relation to the doses administered, and its equivalences in dental practice in panoramic periapical radiographs and cone beam tomographies. A search of the literature was carried out in the main information sources such as Medline (via PubMed), SEVIER, SCIELO, and LILACS, using the search terms with a date limitation of the last 10 years. The selected articles had to include information regarding the keywords used, including "Dental Offices, Radiation Dose, X-Rays, Ambulatory Care."

Radiation exposure to fetus from extremity CBCT examinations

PURPOSE

To evaluate fetal doses from extremity CBCT examinations at different stages of pregnancy and to investigate different methods of fetal dose optimization.

METHOD

Fetal doses were measured in an anthropomorphic phantom for two CBCT examination protocols - knee and elbow. The measurements were made at three different heights representing the three trimesters during pregnancy and three different depths in the phantom. The effect of soft tissue layer, tube voltage, add-on device shield and body angulation on fetal dose were investigated.

RESULTS

The fetal doses in clinical examination protocols were in the range of 3.4 to 6.0 µGy during knee examinations and 2.9 to 7.7 µGy during elbow examinations depending on the depth of the fetus and the stage of pregnancy. A soft tissue layer representing variative body composition above abdomen region decreased the fetal dose up to 19 % in knee and up to 21 % in elbow examinations. Using lower tube voltage decreased the fetal doses up to 45 % (knee) and 51 % (elbow). An add-on device shield decreased the fetal doses up to 91 % (knee) and up to 75 % (elbow). Turning the body away from the device bore reduced the fetal doses up to 62 %. The conversion factor to convert an entrance surface dose to the fetal dose ranged from 0.4 to 0.6.

CONCLUSIONS

The fetal doses from CBCT examinations of extremities are low and do not produce a concern about radiation detriment to the fetus. The most efficient way found to reduce the fetal dose was to use the add-on device shielding.

A historical review of the effects of dental radiography on pregnant patients

BACKGROUND

The safety of dental radiography performed on pregnant patients has been a controversial topic since the 1960s. This review synthesizes and consolidates findings, from 1957 through 2021, of the effects dental ionizing radiation could have on a pregnant patient and in utero birth defects.

TYPES OF STUDIES REVIEWED

Using PubMed, the following key words were searched: pregnancy, radiology, radiograph, radiation dose, fetus, x-ray, and dental. Criteria evaluation was done on the basis of availability, completeness, quality, relevance, technicality (that is, dental radiography), topicality (that is, pregnant patients), and usability. These results were then filtered on the basis of quantitative and qualitative data as well as the period (decades within the historical framework). The final selection of relevant literature consisted of various studies including cohort studies, systematic reviews, meta-analyses, case reports, and other narrative reviews.

RESULTS

If properly performed, the amount of ionizing radiation produced during dental radiographic procedures is so low that it is unlikely to reach the teratogenic threshold. Thus, dental ionizing radiation is unlikely to cause in utero birth defects because it has been detected to have a deterministic (not stochastic) effect. With this information and historical context, this article shows that necessary dental radiography is safe at any stage during pregnancy, as long as proper safety equipment is appropriately used.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

As technology advances, more research can further clarify ionizing radiation safety for pregnant patients and its potential effects on in utero birth defects, improving overall oral health care. The dental community must remain educated about current ionizing radiation safety guidelines to make better-informed decisions and successfully provide proper oral health care to pregnant patients.

Diagnostic performance of the AAP/EFP classification and the CDC/AAP case definition among pregnant women and a practical screening tool for maternal periodontal diseases

BACKGROUND AND OBJECTIVE

There is a limited number of studies on the performance assessment of the 2017 AAP/EFP classification and the CDC/AAP case definition among pregnant females. This study evaluated the agreement between these two systems and explored a practical tool for screening maternal periodontal diseases by general dentists.

MATERIALS AND METHODS

Totally, 204 systemically healthy females at different phases of pregnancy underwent a full-mouth periodontal examination. Demographic characteristics, lifestyles, and systemic conditions were recorded. Referring to the CDC/AAP definition, the diagnostic performance of the AAP/EFP classification was evaluated by the area under the ROC curve (AUC) and statistical tests (e.g., Youden's index and kappa coefficient). Additionally, a modified scoring system of the FDI Periodontal Diseases Chairside Guide (FDI-CG) was formulated with the addition of pregnancy for testing accordingly.

RESULTS

Overall, there were 22.1% of the participants in early phase of pregnancy (7-13 weeks) and 77.9% in late phase (34-36 weeks). The majority of them were below 35 years and non-smokers without gestational diabetes. Notably, 30.9% of subjects presented with Moderate/Severe periodontitis (CDC/AAP), and 35.8% with Stages II-IV periodontitis (AAP/EFP). Referring to the CDC/AAP definition, the AUC, Youden's index, and κ of the AAP/EFP classification were 0.979, 0.890, and 92.9%, respectively. The modified FDI-CG system improved the AUC (0.815), Youden's index (63.0%), and κ (0.544) with reference to the original one.

CONCLUSIONS

This study shows that the AAP/EFP classification is in high agreement with the CDC/AAP definition among the pregnant women. The phases of pregnancy-integrated FDI scoring system may serve as a convenient screening tool for maternal periodontal diseases in general dental practice.

Jordanian women’s (studying or working in medical fields) awareness in terms of the use of dental imaging during pregnancy

Background

The anxiety among pregnant women about the imaging of teeth during pregnancy may have an adverse effect on the oral health of both the mother and the fetus too. This research study was conducted to evaluate women’s knowledge of the utilization of dental imaging during pregnancy.

Methods

In this research, structured questionnaires were distributed electronically through social media. The questionnaires contained questions focused on the women’s (studying or working in medical fields) awareness regarding the ionizing radiation protection that takes place during dental imaging, the safest period for dental imaging, the sort of radiographs that can be required, and the chance of radiation-induced malignant tumor and malformation of the fetal as a result of dental imaging.

Results

Overall, 984 participants completed questionnaires that were analyzed after being received. Most of the participants (n = 637; 64.7%) were < 30 years of age. The greater number of the participants (66.8%) had fair knowledge of dental imaging. 25.4% mentioned that pregnant women are able to do dental imaging during the first trimester. And approximately half of the participants thought that cone-beam computed tomography and panoramic images must not be carried out during pregnancy. Moreover, nearly the same percentage of them also believed that the risk of inborn malformation is high due to dental imaging.

Conclusions

The results refer to a low awareness among people who have medical knowledge regarding dental radiograph protection during pregnancy. This needs to be paid attention to among students, graduates, and workers in medical fields by focusing on the courses and lectures related to dental imaging protection during pregnancy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02459-w.

Oral administration of inorganic nitrate alleviated biological damage induced by cone-beam computed tomography examination in Wistar rats

OBJECTIVES

To explore whether the inorganic nitrate has a protective effect on biological damage induced by cone-beam computed tomography (CBCT) and compare it with Vitamin C.

MATERIALS AND METHODS

Sixty Wistar rats were randomly separated into 6 groups: control group, irradiation (IR) group, NaNO₃ group, IR + NaNO₃ group, Vitamin C group, and IR + Vitamin C group. Rats were whole-body irradiated with CBCT four times. The absorbed dose of the skin surface was measured using thermoluminescent dosemeter chips and the mean whole-body absorbed dose was calculated. Peripheral blood was collected at 0.5h and 24h after irradiation. Bodyweight and organ index of rats before and after irradiation were analyzed. The bone marrow was taken for micronucleus test. Lymphocytes were isolated from peripheral blood for γ-H2AX immunofluorescence assay, apoptosis and reactive oxygen species (ROS) analysis. Total antioxidant capacity (TAC), malondialdehyde (MDA) and superoxide dismutase (SOD) in serum were detected.

RESULTS

The mean absorbed dose of four whole-body CBCT scans for rats was 73.04 mGy. Bodyweight and organ index before and after irradiation with X-ray had no significant differences. The micronuclei frequency of IR + NaNO3 and IR + Vitamin C groups showed a significant decrease than that in the IR group, which was not significantly different from that of the control group. The γ-H2AX foci rates in the IR + NaNO3 group and the IR + Vitamin C group were significantly lower than that in the IR group. In addition, the foci rate of the IR + NaNO3 group returned to the baseline level of the control group 24h after CBCT scanning. The apoptosis of lymphocytes in rats did not increase. The IR + NaNO3 group (P < 0.001) or IR + Vitamin C group (P < 0.001) showed a significant increase in ROS positive cells rate with the control group, while were significantly lower than those in the IR group (P < 0.01). In addition, the ROS-positive cell rate in the IR + NaNO3 group was significantly lower than that in the IR + Vitamin C group. The MDA in the serum of rats increased significantly, while SOD and TAC decreased significantly at 0.5h after irradiation.

CONCLUSIONS

Compared with Vitamin C, inorganic nitrate had better preventive effects on biological damage induced by CBCT scans in rats.

Occupational and patients effective radiation doses in dental imaging

Ionizing radiation exposure from medical applications is increasing annually worldwide. It was estimated that 325 million dental procedures were performed in the United States. Radiation exposure from dental radiography consists of intraoral, panoramic, and 3D imaging cone-beam computed tomography (CBCT) imaging. Recent studies reported an association between dental imaging procedures and increased cancer probability of brain and thyroid. Previous studies showed that some dental imaging practices exposed patients and staff to unnecessary radiation doses due to incorrect image acquisition and insufficient radiation protection measures. This study aims to (i) measure the occupational and patients doses during dental procedures and (ii) assess the current imaging techniques and radiation protection practices. Two hundred fourteen patients were evaluated for periapical, bitewing, cephalometric, occlusal, and panoramic procedures. Organ equivalent doses were quantified for the breast, eye lens, and thyroid gland during CBCT procedure. Occupational and ambient dose assessment were assessed using calibrated thermoluminescent dosimeters (TLD-100(LiF: Mg. Ti). Ambient doses were measure at different locations at the department using TLDs. Patients' radiation doses were quantified using kerma area product (PKA (mGy.cm) and the entrance surface air kerma (ESAK (mGy). Fixed tube voltage (65 kVp) and tube current-time product (7 mAs) were used. The overall mean, sd, and range of patients dose values during intraoral (mGy), panoramic and CBCT examinations were 4.6 ± 0.7 (1.4-7.1), 135 ± 45 (75.2-168.5), and 215 ± 165 (186-2115), respectively. The mean and range of the annual occupational doses (mSv) were 1.4 (0.6-3.7), which below the annual dose limits for radiation workers (20 mSv/y). The study showed that inadequate radiation protection for patients existed in terms of the use of the thyroid shield, the technologist's presence inside the room during radiation exposure. Patients' radiation doses were comparable with the international diagnostic reference level (DRL). Staff education and training in radiation protection aspects are highly recommended.

Women's awareness regarding the use of dental imaging during pregnancy

Background

There is often anxiety among pregnant women about dental imaging during pregnancy. This may hinder some women from seeking dental treatment during pregnancy and consequently, may negatively affect the oral health of the mother and fetus. This study was conducted to assess women’s awareness regarding the use of dental imaging during pregnancy.

Methods

In this cross-sectional study, the electronic distribution of structured questionnaires was done via social media. The self-administered questionnaires contained questions related to women’s knowledge regarding the radiation protection measures during dental imaging, the safest period for dental imaging, the type of radiographs that can be acquired during pregnancy, and the possibility of radiation-induced malignancy and fetal malformation as a result of dental imaging.

Results

In total, 410 completed questionnaires were received and analyzed. More than half of the participants were 30–49 years of age. The majority of the participants (91%) demonstrated poor knowledge concerning dental imaging. Only 4% reported that pregnant women can have dental imaging during any trimester. The majority believed that panoramic images and cone-beam computed tomography should not be acquired during pregnancy. The majority also believed there is a high risk of congenital malformation due to dental imaging and were unsure about the oncogenic risks.

Conclusions

Our study suggests that there is insufficient knowledge about dental imaging safety during pregnancy. This misconception may have a direct impact on the attitude toward seeking dental care. Therefore, community awareness initiatives aimed at informing our society about radiation exposure, safety, and required protection measures are critical.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01726-6.

Dental cone beam CT: An updated review

Cone beam computed tomography (CBCT) is a diverse 3D x-ray imaging technique that has gained significant popularity in dental radiology in the last two decades. CBCT overcomes the limitations of traditional two-dimensional dental imaging and enables accurate depiction of multiplanar details of maxillofacial bony structures and surrounding soft tissues. In this review article, we provide an updated status on dental CBCT imaging and summarise the technical features of currently used CBCT scanner models, extending to recent developments in scanner technology, clinical aspects, and regulatory perspectives on dose optimisation, dosimetry, and diagnostic reference levels. We also consider the outlook of potential techniques along with issues that should be resolved in providing clinically more effective CBCT examinations that are optimised for the benefit of the patient.

ESTIMATING RADIATION DOSE TO MAJOR ORGANS IN DENTAL X-RAY EXAMINATIONS: A PHANTOM STUDY

The radiation doses absorbed by major organs of males and females were studied from three types of dental X-ray devices. The absorbed doses from cone-beam computed tomography (CBCT), panoramic and intraoral X-ray machines were in the range of 0.23-1314.85 μGy, and were observed to be high in organs and tissues located in or adjacent to the irradiated area, there were discrepancies in organ doses between male and female. Thyroid, salivary gland, eye lens and brain were the organs that received higher absorbed doses. The organ absorbed doses were considerably lower than the diagnostic reference level for dental radiography in China. The calculated effective radiation doses for males and females were 56.63, 8.15, 2.56 μSv and 55.18, 8.99, 2.39 μSv, respectively, when using CBCT, the panoramic X-ray machine and intraoral X-ray machine. The effective radiation dose caused by CBCT was much higher than those of panoramic and intraoral X-ray machines.

Comparison of air dose and operator exposure from portable X-ray units

This study was aimed at investigating and comparing exposure dose of workers and the surrounding workers. In addition, worker's exposure was also measure about lens and finger. Four intraoral portable X-ray units were evaluated. The stray radiations were measured using Pitman 37D and ionization chamber (Pitman). MyDosemini (ALOKA) was used for measurement of the finger exposure dose. Without the shield became high in anterior 0.5 m. Comparing the air dose for the four models used in this study showed a high tendency for the two NOMAD models. And using the shields, the images could be taken 4.6 times of the baseline at a maximum and 3.6 times on average. The finger radiation exposure dose was low with both of the NOMAD models, with no significant difference found. By setting the baseline value without a shield, finger radiation exposure when using a shield was lower than the detection limit for the D3000, and was reduced by approximately 94-96% for other three models. All models can photograph around 100 bodies, so it is considered that it is not necessary to switch out the operator considering the operation limit. But even if it does not reach the operation limit, the stochastic effects of radiation exposure can be increased as well as the deterministic effects of the operation limit. The operator and the surrounding workers seek to protect themselves. It is important to perform exposure management that takes into account the stochastic effects to the operator and the surrounding workers.

ESTIMATION OF EFFECTIVE DOSE OF DENTAL X-RAY DEVICES

This study aims to estimate the effective doses of dental X-ray devices under common scanning protocols. After putting TLDs in the Alderson Radiation Therapy Phantom, we exposed the phantom under common scanning protocols of three dental X-ray devices, namely CBCT, dental panoramic machine and intraoral round cone device. Then effective doses were calculated using the measured absorbed doses of organs and tissues. Tissue weighting factors recommended by the ICRP were adopted in the calculation. Effective doses under common scanning protocols of three Dental X-ray devices were obtained. The effective dose of dental CT was 0.20 mSv, and that of dental panoramic machine and intraoral radiography were 0.013 and 0.0050 mSv, respectively. The tissue absorbed doses of dental CT scan were 0.63 mGy of brain, 7.7 mGy of salivary glands, 8.7 mGy of thyroid and 4.0 mGy of the lens of the eye. The tissue absorbed doses from dental panoramic machine are 0.62 mGy of salivary glands and 0.25 mGy of thyroid. And finally the tissue absorbed dose of intraoral radiography was 0.80 mGy of salivary gland. Among the three dental X-ray devices studied, dental CBCT scan can cause much higher effective dose than the other two. Brain, salivary glands, thyroid and the lens of the eye are tissues receiving relatively higher absorbed doses.

Novel low-dose protocols using cone beam computed tomography in dental medicine: a review focusing on indications, limitations, and future possibilities

OBJECTIVES

A narrative review on the potential use of low-dose protocols for cone beam computed tomography (CBCT) was conducted to identify indications and their relevance for various dental disciplines.

MATERIALS AND METHODS

Google Scholar was searched using the words "low-dose CBCT". Reviews, consensus papers, clinical studies, and experimental studies were eligible for the initial screening process, but for data extraction only original articles were selected. Similar search procedures were then performed with the additional search words "pedo," "ortho," "endo," "implant," "perio," and "oral surgery." Furthermore, references of included articles were examined to identify further relevant articles.

RESULTS

After screening, 27 publications remained for the data extraction process. Low-dose protocols have been reported for specialties such as pediatric dentistry (evaluating orofacial clefts, periapical lesions, impacted teeth, and autotransplantation), orthodontics (cephalometric analysis and interim assessment of treatment results), endodontics (detecting root fractures, resorptions and periapical bone loss), implant dentistry (planning implant insertion, evaluating peri-implant fenestration and dehiscence), periodontology (assessing periodontal structures), and oral and maxillofacial surgery (assessing mandibular third molars and TMJs). Nevertheless, most of the literature available is related to non-clinical studies. Furthermore, there is a lack of position statements or guidelines from authoritative bodies regarding the use of low-dose protocols in dental medicine.

CONCLUSIONS

Low-dose protocols for CBCT imaging seem to have potential in various disciplines in dental medicine ranging from pediatric dentistry to oral and maxillofacial surgery. Dose reduction is usually achieved by mAs reduction, use of partial rotations, reduced number of projections, and larger voxel sizes, but seldom by kV reduction.

CLINICAL RELEVANCE

Albeit low-dose protocols have potential to result in a reduction of dose exposure for 3D imaging due to dental indications, there is a need to more clearly specify indications and limitations to avoid indiscriminate use of standard and high-dose CBCT scans in the future on the lines of ALARA/ALADA principles.

Oral care in pregnancy

Pregnant women are susceptible to a wide range of oral health conditions that could be harmful to their own health and the future of their baby. There are many myths about the safety of dental care during pregnancy. As a result, pregnant women receive less dental care than when they are not pregnant. In our review, we tried to emphasize the importance and safety of routine dental care for pregnant women.