Fernanda Angelieri

DNA damage and cellular death in oral mucosa cells of children who have undergone panoramic dental radiography

BackgroundDespite wide use as a diagnostic tool in medical and dental practice, radiography can induce cytotoxic effects and genetic damage.ObjectiveTo evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) in exfoliated buccal mucosa cells taken from healthy children following exposure to radiation during dental radiography.Materials and methodsA total of 17 children who had undergone panoramic dental radiography were included.ResultsWe found no statistically significant differences (P > 0.05) between micronucleated oral mucosa cells in children before and after exposure to radiation. On the other hand, radiation did cause other nuclear alterations closely related to cytotoxicity including karyorrhexis, pyknosis and karyolysis.ConclusionTaken together, these results indicate that panoramic dental radiography might not induce chromosomal damage, but may be cytotoxic. Overall, the results reinforce the importance of evaluating the health side effects of radiography and contribute to the micronucleus database, which will improve our understanding and practice of this methodology in children.

Cytogenetic biomonitoring of oral mucosa cells from adults exposed to dental X-rays.

PurposeAlthough it has been clearly demonstrated that X-rays play a key role in diagnosing medical and dental problems, this type of ionizing radiation is also able to induce noxious activities, such as genetic damage. The aim of the present study was to evaluate DNA damage (micronucleus) and cellular death in exfoliated buccal mucosa cells from healthy individuals (smokers and nonsmokers) following dental X-ray exposure.Material and methodsA total of 39 healthy people who had submitted to panoramic dental radiography were included in the study: 9 smokers and 30 nonsmokers.ResultsThe results indicated no significant statistically differences (P > 0.05) in micronucleated oral mucosa cells before and after dental X-ray exposure. On the other hand, X-ray exposure did increase other nuclear alterations closely related to cytotoxicity, such as karyorrhexis, pyknosis, and karyolysis. It seems that cigarette smoke did not affect X-ray outcomes induced in buccal cells.ConclusionThese data indicate that dental panoramic radiography may not induce chromosomal damage, but it is able to promote cytotoxicity. Because cellular death is considered a prime mechanism in nongenotoxic mechanisms of carcinogenesis, dental X-ray should be used only when necessary.

Surgical planning for resection of an ameloblastoma and reconstruction of the mandible using a selective laser sintering 3D biomodel

Ameloblastoma is a benign locally aggressive infiltrative odontogenic lesion. It is characterized by slow growth and painless swelling. The treatment for ameloblastoma varies from curettage to en bloc resection, and the reported recurrence rates after treatment are high; the safety margin of resection is important to avoid recurrence. Advances in technology brought about great benefits in dentistry; a new generation of computed tomography scanners and 3-dimensional images enhance the surgical planning and management of maxillofacial tumors. The development of new prototyping systems provides accurate 3D biomodels on which surgery can be simulated, especially in cases of ameloblastoma, in which the safety margin is important for treatment success. A case of mandibular follicular ameloblastoma is reported where a 3D biomodel was used before and during surgery.

Cytogenetic biomonitoring in patients exposed to dental X-rays: comparison between adults and children

OBJECTIVES The aim of the present study was to comparatively evaluate the DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) of exfoliated buccal mucosa cells from children and adults following dental X-ray exposure. METHODS A total of 17 adults and 17 children submitted to panoramic dental radiography were included in this study. RESULTS The results indicated no statistically significant differences (P > 0.05) in childrens micronucleated oral mucosa cells before and after dental X-ray exposure. In the same way, no mutagenic effects were observed in adults following X-ray exposure. On the other hand, X-rays increased other nuclear alterations closely related to cytotoxicity such as karyorrhexis, pyknosis and karyolysis in both groups. The comparative analysis between children and adults demonstrated no statistically significant differences in micronucleus frequency or cytotoxicity (P > 0.05). CONCLUSIONS In summary, these data indicate that dental paroramic radiography may not be a factor that induces chromosomal damage, but it is able to promote cytotoxicity. It seems that children are not more susceptible to the noxious activities induced by X-rays when compared with adults.

Biomonitoring of oral epithelial cells in smokers and non-smokers submitted to panoramic X-ray: comparison between buccal mucosa and lateral border of the tongue

The aim of the present study was to comparatively evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis, and karyorrhexis) in exfoliated oral mucosa cells from smokers and non-smokers submitted to dental X-ray using two anatomic sites: buccal mucosa and lateral border of the tongue. A total of 15 heavy smokers and 17 non-smokers were submitted to panoramic dental radiography for orthodontic reasons. Individuals had epithelial cells from cheek and lateral border of the tongue mechanically exfoliated, placed in fixative, and dropped in clean slides which were checked for the above nuclear phenotypes. The results pointed out no significant statistically differences (p > 0.05) of micronucleated oral mucosa cells before versus after X-ray exposure for both oral sites evaluated either to smokers or to non-smokers. X-ray exposure was able to increase other nuclear alterations closely related to cytotoxicity such as karrhyorexis, pyknosis, and karyolysis for two groups evaluated. Nevertheless, the most pronunciated effects were found to lateral border of the tongue of smokers. In summary, these data indicate that panoramic X-ray is able to induce cellular death in oral mucosa cells. It seems that lateral border of the tongue is more sensitive site to cytotoxic insult induced by ionizing radiation combined with continuous cigarette smoke exposure.

Biomonitoring of mutagenicity and cytotoxicity in patients undergoing fixed orthodontic therapy

INTRODUCTION The aim of the present study was to evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis, and karyorrhexis) in exfoliated buccal mucosa cells from adults after fixed orthodontic therapy. MATERIAL AND METHODS A total of 23 healthy adults (10 men and 13 women) undergoing orthodontic therapy were included in this setting. RESULTS The results pointed out no significant statistically differences (P >0.05) of micronucleated oral mucosa cells. In the same way, orthodontic therapy was not able to increase other nuclear alterations closely related to cytotoxicity such as karyorrhexis, pyknosis and karyolysis (P >0.05). CONCLUSION In summary, these data indicate that orthodontic therapy may not be a factor that induces chromosomal damage, nor it is able to promote cytotoxicity. Since DNA damage and cellular death are important events during carcinogenic processes, especially in early phases, this study represents a correct evaluation with respect to real health risks induced by orthodontic devices.

Mutagenicity and cytotoxicity assessment in patients undergoing orthodontic radiographs

OBJECTIVES The aim of the present study was to evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) in exfoliated buccal mucosa cells from individuals following radiography. METHODS Lateral and frontal cephalometric X-ray and panoramic dental X-rays were taken of a total of 18 healthy patients (6 male and 12 female) referred for orthodontic therapy. Exfoliated oral mucosa cells were collected immediately before X-ray exposure and after 10 days. RESULTS The results revealed no statistically significant difference (P > 0.05) in the frequency micronucleated oral mucosa cells after X-ray exposure. However, X-ray was able to increase other nuclear alterations closely related to cytotoxicity, such as karyorrhexis, pyknosis and karyolysis. CONCLUSIONS Data indicated that exposure to certain radiography may not be a factor in inducing chromosomal damage, but it does promote cytotoxicity.

Genotoxicity of corrosion eluates obtained from orthodontic brackets in vitro

INTRODUCTION The purpose of this study was to evaluate whether corrosion eluates obtained from commercially available orthodontic brackets are able to induce genetic damage in vitro. MATERIAL AND METHODS Genotoxicity was assessed by the single cell gel (comet) assay using Chinese hamster ovary (CHO) cells. The following orthodontic metallic brackets were used: Morelli (Sorocaba, Brazil); Abzil (São José do Rio Preto, Brazil); Dentaurum (Pforzheim, Germany); and 3M Unitek (Puchheim, Germany). Each dental bracket was submitted to a corrosion process in a solution containing equal amounts of acetic acid and sodium chloride at 0.1 M concentration for 1, 3, 7, 14, 21, 35, and 70 days. CHO cells were exposed to eluates for 30 minutes at 37°C. The negative control was treated with the same solution used for corrosion process for 30 minutes at 37°C. Independent positive control was performed with methyl methanesulfonate (MMS) (Sigma Aldrich, St. Louis, Mo) at 1 ug/mL for 1 hour. RESULTS None of the eluates was found to exhibit genotoxicity, regardless of the different commercial brands of orthodontic appliance used. CONCLUSIONS In summary, our results indicate corrosion eluates obtained from orthodontic brackets do not induce genetic damage as assessed by single cell gel (comet) assay.

Genotoxicity and cytotoxicity induced by eluates from orthodontic glass ionomer cements in vitro

The aim of this study was to investigate genotoxicity and cytotoxicity of some orthodontic glass ionomer cements commercially available by means of the single cell gel (comet) assay. For this purpose, five commercial orthodontic glass ionomer cements (Vidrion C®, Meron®, Optiband®, Multicure® and Ultra Band Lok®) were tested in murine fibroblasts in vitro. For this purpose, eluates from each cement were prepared according manufactures instructions at 0, 2, 4, 8, 18, 32 and 64 days of immersion in artificial saliva at 37 °C. All orthodontic glass ionomer cements failed to induce cytotoxicity to murine fibroblasts for all periods evaluated in this study. However, Vidrion C® was able to induce genotoxicity after 64 days of exposure to eluates. Meron® also demonstrated genotoxicity as depicted by increasing DNA damage on 2nd day. Multicure® demonstrated genotoxicity on 32nd day and Ultra band Lok on 18th, 32nd days of exposure. Taken together, our results demonstrated that orthodontic cements derived from resin-modified glass ionomer composite (Multicure®) and compomer (Ultra Band Lok®) cause genetic damage in mammalian cells in vitro.