Cytogenetic biomonitoring in individuals exposed to cone beam CT: comparison among exfoliated buccal mucosa cells, cells of tongue and epithelial gingival cells

A systematic review and meta-analysis of the genotoxic and cytotoxic effects on oral epithelium induced by cone beam computed tomography

OBJECTIVE

To evaluate the occurrence of genotoxic and cytotoxic effects in oral epithelium after exposure of patients to cone beam computed tomography (CBCT).

METHODS

A systematic review (SR) was conducted following the PECO (Population, Exposure, Comparison, Outcome) criteria. The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO). A search was performed on the PubMed, Scopus, ScienceDirect, and Google Scholar databases. Effect size and heterogeneity of data were evaluated statistically. The Joanna Briggs Institute questionnaire for observational studies was utilized to assess the risk of bias. The GRADE tool was applied for the assessment of the quality of evidence. Begg's funnel plot was used to evaluate publication bias.

RESULTS

In total, 10 full-text articles were included in the SR, with 6 of them in the meta-analysis. The SR showed a significant increase in micronuclei after exposure, with a large effect size of 1.03. For genotoxicity, the tau2 for heterogeneity was 0.96, the chi-squared test for heterogeneity P < .00001, the I2 statistics for random effects was 91%, and the overall effect for Z value was 2.46 (P = .01). The risk of bias was low, the quality of evidence was strong, and publication bias was absent.

CONCLUSION

CBCT can cause genotoxicity in the oral epithelium with a large effect size. The measure of cytotoxicity after CBCT exposure was not possible due to the lack of homogeneity of the included articles.

Is micronucleus assay a useful marker in gingiva, tongue, and palate for evaluating cytogenetic damage induced by chemical, physical, and biological agents in vivo? A systematic review with meta-analysis

The present systematic review (SR) aims to evaluate manuscripts in order to help further elucidate the following question: is the micronucleus assay (MA) also a useful marker in gingiva, tongue, and palate for evaluating cytogenetic damage in vivo? A search was performed through the electronic databases PubMed/Medline, Scopus, and Web of Science, all studies published up to December 2023. The comparisons were defined as standardized mean difference (SMD), and 95% confidence intervals (CIs) were established. Full manuscripts from 34 studies were carefully selected and reviewed in this setting. Our results demonstrate that the MA may be a useful biomarker of gingival tissue damage in vivo, and this tissue could be a useful alternative to the buccal mucosa. The meta-analysis analyzing the different sites regardless of the deleterious factor studied, the buccal mucosa (SMD = 0.69, 95% CI, - 0.49 to 1.88, p = 0.25) and gingiva (SMD = 0.31, 95% CI, - 0.11 to 0.72, p = 0.15), showed similar results and different outcome for the tongue (SMD = 1.19, 95% CI, 0.47 to 1.91, p = 0.001). In summary, our conclusion suggests that the MA can be a useful marker for detecting DNA damage in gingiva in vivo and that this tissue could be effective site for smearing.

Genotoxic and Cytotoxic Effects of Cone Beam Computed Tomography and Multidetector Computed Tomography on Exfoliated Buccal Epithelial Cells

Background

Cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) are frequently used in dental and maxillofacial problems. This study aimed to assess the genotoxicity and cytotoxicity effects of CBCT and MDCT radiographies on exfoliated buccal epithelial cells during dental examinations.

Methods

This prospective experimental study was conducted at Babol University of Medical Sciences (Babol, Iran) from March 2021 to April 2021. Buccal mucosa smears were collected bilaterally pre-exposure and 12 days after CBCT or MDCT examinations. To compare the frequency of micronuclei and other cytotoxic cellular changes such as pyknosis, karyolysis, and karyorrhexis, the paired sample t test and Wilcoxon test were used. In addition, independent sample t test, Mann-Whitney, and Chi square tests were used to investigate the differences between the imaging methods and between men and women. All statistical analyses were performed using the SPSS software, and P≤0.05 was considered statistically significant.

Results

The current study included 60 adult patients (30 patients in each group), ranging in age from 21 to 50 years. The micronuclei and the other cytotoxic cellular changes increased significantly after CBCT and MDCT radiographic examinations on the 12th day compared to the pre-exposure results (P<0.001). MDCT had statistically higher cytotoxic and genotoxic effects than CBCT (9.4%, 23.1%, and 40% higher values in micronucleus frequency, the mean frequency of micronuclei, and other cytotoxic changes, respectively). There were no significant differences between men and women in the two examination methods (P=0.46 and P=0.49, respectively).

Conclusion

Dental examinations with CBCT and MDCT can increase cytotoxicity and chromosomal damage in both men and women. Due to its lower radiation toxicities, CBCT can be recommended as an alternative to MDCT for dental examinations.

Does cone-beam computed tomography examination increase the micronuclei frequency in the oral mucosa exfoliated cells? A systematic review and meta-analysis

OBJECTIVE

This systematic review (SR) with meta-analysis aimed to evaluate the frequency of micronuclei in the oral mucosa exfoliated cells after cone-beam computed tomography (CBCT) examination.

METHODS

We performed language-independent computer-assisted data searches using PubMed databases, Cochrane, Embase, Web of Science all databases, and Google Scholar. The literature on micronucleus (MN) frequency of clinical trials before and after CBCT examination was included. The frequency of MN in exfoliated cells of the human oral mucosa was the primary outcome of the study. All statistical analyses were performed with R (version 4.1.0), RStudio (version 2022.02.2 + 485) software, and Meta packages (version 5.2-0). Two reviewers independently assessed the quality of the included studies by the EPHPP (Effective Public Health Practice Project) Modified scale with minor modifications. The heterogeneity of the data was analyzed using I² statistics, in which I² > 50% was considered substantial heterogeneity.

RESULTS

A total of 559 articles were selected through the search strategy. After screening titles and abstracts, nine full-text manuscripts were assessed for eligibility, and six observational studies were included in the meta-analysis. The present study showed a significant increase in MN frequency of human oral mucosal exfoliated cells 10 days after CBCT examination compared to baseline (SMD = - 0.56, 95%-CI = - 0.99 ~ - 0.13, p = 0.01). Because of the high heterogeneity among the studies (I² = 72%), after removing one study that was the main source of heterogeneity, excluding the study (I² = 47%), the common-effect model was chosen, and the meta-analysis also showed that the frequency of MN in human oral mucosa exfoliated cells increased significantly 10 days after CBCT examination (SMD =  - 0.35, 95%-CI =  - 0.59 ~  - 0.11, p = 0.004).

CONCLUSION

This review suggested that CBCT examination increases the frequency of micronuclei in oral mucosal exfoliated cells.

Genotoxicity and cytotoxicity effects of x-rays on the oral mucosa epithelium at different fields of view: A cone beam computed tomography technique

Background

Cone beam computed tomography (CBCT) is considered a common examination for dentistry problems. Cellular biology can be affected by exposure to ionizing radiations procedures. In this study, we aimed to assess the genotoxicity and cytotoxicity effects of CBCT dental examinations at two different fields of view (FOVs) in exfoliated buccal epithelial cells.

Methods

Sixty healthy adults participated in the current study. They were divided into two identical groups; CBCT with FOV of 6*6 cm2 and 8*11 cm2. Exfoliated oral mucosa cells were prepared immediately before and after 10-12 days of CBCT exposure. The cytological smears were stained with the Papanicolaou technique. The amounts of micronuclei and other cytotoxicity cellular changes (Pyknosis, Karyolysis, and Karyorrhexis) were evaluated. The variables of the parameters before and after CBCT examination in the two investigated FOVs were performed using Wilcoxon test and paired-samples t-test in SPSS software.

Results

The micronuclei and other cytotoxic changes parameters before and after CBCT exposure for both FOVs (6*6 and 8*11 cm2) increased significantly (p<0.001). Furthermore, a significant difference (p<0.05) was observed between the investigated parameters at the two FOVs. Notably, the FOV of 8*11 cm2 had more side effects than that of 6*6 cm2. There were no statistically significant among males and females for both FOVs.

Conclusion

CBCT examinations of dental disorders would increase the risks of inducing genetic damage. The cytotoxicity and chromosomal damage were considered in males and females in both investigated FOVs (6*6 and 8*11 cm2). In this regard, the use of CBCT must be following the ALARA principle.

Cytotoxicity, genotoxicity, and immunohistochemical expression of p53 in the oral mucosal epithelium of adults following cone-beam computed tomography

This study sought to assess the cytotoxicity, genotoxicity, and immunohistochemical (IHC) expression of p53 in the oral mucosal epithelium of adults following cone-beam computed tomography (CBCT). This before-and-after observational study evaluated 30 patients (15 males and 15 females); mean age 35 years, who required CBCT. Exfoliating epithelial cells of the buccal mucosa were collected with a cotton swab immediately before and 10 days after CBCT. Following Papanicolaou staining, genotoxicity was evaluated by the micronucleus assay. The frequencies of pyknosis, karyorrhexis, karyolysis, budding and binucleation as cytotoxicity factors were also recorded. Expression of p53 was evaluated by IHC staining. Data were analyzed by paired samples t-test. Micronucleated cells, pyknosis, karyorrhexis, karyolysis, budding, cytotoxicity, and expression of p53 increased significantly after CBCT. CBCT exerts genotoxic and cytotoxic effects and leads to overexpression of p53 protein in the oral buccal mucosal cells.

Ovarian tissue features assessed in bovine fetuses after vitrification and xenotransplantation procedures

Cryopreservation and transplantation of ovarian tissue are proposed methods for the restoration of endocrine function and reproductive potential. Therefore, this study aimed to evaluate the effects of vitrification and xenotransplantation on follicle viability, activation, stromal cell integrity, vascularization, and micronuclei formation. Bovine fetal ovaries were fragmented and assigned to the following groups: Fresh control (FC), ovarian fragments immediately fixed; Vitrified control (VC), ovarian fragments vitrified; Vitrified xenotransplanted (VX), ovarian fragments vitrified and xenotransplanted; and Fresh xenotransplanted (FX), ovarian fragments xenotransplanted. Ovarian fragments were grafted in female BALB/c mice and recovered after 14 days. Follicular viability was preserved (P >  0.05) in VC group. The rate of developing follicles was greater (P <  0.05) in the FX group compared to other groups. Follicular density was higher (P <  0.05) in the VC group than the FC, VX, and FX groups. A decrease (P <  0.05) of stromal cell density was recorded after vitrification (VC vs. FX). Blood vessel density decreased in VC, VX, and FX groups compared with the FC group, and blood vessel density was correlated with follicular viability (positively; P =  0.07) and developing follicles (negatively; P <  0.001). Both vitrification and xenotransplantation groups (VC, VX, and FX) had a greater (P <  0.05) number of cells with one MN compared to the FC group. In summary, our findings showed that both vitrification and xenotransplantation modified blood vessel, follicular and stromal cell densities, follicular viability and activation, and micronuclei formation in ovarian tissue.

Genotoxicity and cytotoxicity of cone beam computed tomography in children

BACKGROUND

Dental radiographs are essential tools for diagnosis. However, there are significant concerns about the dangerous effect of radiation especially on children. The aim of this study was to evaluate genotoxicity and cytotoxicity in the exfoliated cells of buccal mucosa of children subjected to Cone Beam Computed Tomography (CBCT).

METHODS

The study included 18 healthy children aged (9-12 years) who were exposed to CBCT. All CBCT scans were performed with the i-CAT CBCT. Exfoliated buccal cells were scraped from the left and right cheek immediately before the exposure, after 10 ± 2 days, and after 1 month. Cells were stained using Feulgen/fast green stain and examined under light microscopy. Genotoxicity (Micronuclei) and cytotoxicity (condensed chromatin, karyorrhexis, pyknosis, and karyolysis) were scored. Statistical analysis was performed using the McNemar test, Wilcoxon Signed-Rank test, and Mann-Whitney U test at a significance level of p < 0.05.

RESULTS

There were statistically significant differences in the mean percentages of micronuclei, condensed chromatin, karyorrhexis, pyknosis, and karyolysis before and 10 ± 2 days after the CBCT scan (p < 0.05). There were no statistically significant differences in the frequency of micronuclei, condensed chromatin, karyorrhexis, or pyknosis before and 1 month after the exposure (p > 0.05) except for karyolysis (p < 0.05).

CONCLUSIONS

CBCT may induce genotoxicity and cytotoxicity in buccal mucosa cells of children. Therefore, CBCT should not be prescribed unless necessary as it cannot be considered a risk-free procedure.

Radiobiological risks following dentomaxillofacial imaging: should we be concerned?

OBJECTIVES

This review aimed to present studies that prospectively investigated biological effects in patients following diagnostic dentomaxillofacial radiology (DMFR).

METHODS

Literature was systematically searched to retrieve all studies assessing radiobiological effects of using X-ray imaging in the dentomaxillofacial area, with reference to radiobiological outcomes for other imaging modalities and fields.

RESULTS

There is a lot of variability in the reported radiobiological assessment methods and radiation dose measures, making comparisons of radiobiological studies challenging. Most radiological DMFR studies are focusing on genotoxicity and cytotoxicity, data for 2D dentomaxillofacial radiographs, albeit with some methodological weakness biasing the results. For CBCT, available evidence is limited and few studies include comparative data on both adults and children.

CONCLUSIONS

In the future, one will have to strive towards patient-specific measures by considering age, gender and other individual radiation sensitivity-related factors. Ultimately, future radioprotection strategies should build further on the concept of personalized medicine, with patient-specific optimization of the imaging protocol, based on radiobiological variables.

Biomonitoring of children and adolescents using orthodontic appliances made of acrylic resins through micronucleus testing of exfoliated buccal and palatal mucosa cells

INTRODUCTION

The present study aimed to investigate the occurrence of micronuclei and the degenerative nuclear alterations indicative of apoptosis and necrosis in the exfoliated buccal and palatal mucosa cells of children and adolescents using orthodontic appliances made of self-curing acrylic resins.

METHODS

The micronuclei and nuclear alterations were evaluated in a minimum of 2000 cells collected from the cheeks and palates of 30 patients of both sexes, aged between 6 and 12 years. The cell evaluations were performed before appliance installation and 15 to 21 days after installation. A conditional test was used. In all analyses, the significance level was 5%.

RESULTS

No differences in the occurrence of micronuclei or the nuclear degenerative changes indicative of apoptosis and necrosis were observed in the cheek cells between the 2 time points (P > 0.05). However, evaluation of the palate cells revealed a significant increase in the occurrence of micronuclei and the nuclear alterations indicative of apoptosis (P < 0.01) but not of karyolysis (P > 0.05).

CONCLUSIONS

Direct contact of orthodontic appliances made of acrylic resins with the oral mucosa increases the incidence of chromosomal damage and degenerative nuclear alterations.

Potential biological damage of human peripheral blood lymphocytes induced by computed tomography examination of the oromaxillofacial region

OBJECTIVES

The aim of this study was to examine whether oromaxillofacial computed tomography (CT) examination causes biologic damage in lymphocytes and whether the biologic damage is related to radiation dose, patient age, or gender.

STUDY DESIGN

Peripheral blood was taken from 51 individuals and divided into control, in vivo, and in vitro irradiation groups. Biologic damage was assessed by comparing rates of chromosomal aberrations (CAs), including dicentric chromosomes (dics), centric rings, and acentric fragments; and nuclear aberrations, including micronuclei (MN), nuclear buds (NBUDs), and nucleoplasmic bridges (NPBs) in the peripheral blood before and after CT examination. Absorbed and effective doses were calculated with the software VirtualDose, and the blood dose was estimated accordingly.

RESULTS

The rates of acentric fragments, MN, NBUDs, and NPBs in the in vivo (P ≤ .008) and in vitro (P ≤ .003) irradiation groups were significantly higher than those in the control groups. The acentric fragment rate (P = .013) and MN rate (P = .002) were higher in the in vitro group than in the in vivo group. There was no correlation between change rates of CAs and nuclear aberrations with radiation dose. Positive correlations of MN rates with age were found in all groups (ρ ≥ 0.590).

CONCLUSIONS

Certain doses of radiation in oromaxillofacial CT examination may induce CAs and nuclear aberrations in lymphocytes.