Imagine a panoramic dental X-ray being taken within seconds. The patient sits down, the machine rotates, and the image appears on the screen. The process seems simple, almost without consequences. Yet behind that brief burst of X-rays, gingival mucosal cells tell another story: traces of DNA damage that can be measured and detected without any invasive procedure.
That is the central finding of research by Dr. drg. Rurie Ratna Shantiningsih, MDSc, and her team from the Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Universitas Gadjah Mada. Their study, published in the Malaysian Journal of Medicine and Health Sciences in September 2022, demonstrated that 8-oxo-dG levels in gingival crevicular fluid correlate strongly with an increase in micronuclei following panoramic radiographic exposure, using both conventional and digital techniques.
A Small Marker with a Big Message
Micronuclei are small fragments located outside the main cell nucleus, measuring approximately one-third to one-fifth the size of the primary nucleus and displaying a similar staining pattern. Their presence is not accidental. They are markers of genomic instability, signaling that cells have experienced genotoxic stress.
Traditionally, detecting micronuclei requires collecting oral mucosal cells through a scraping procedure and examining them under a microscope. This can be time-consuming and requires specialized expertise. This raises the question: is there a simpler way to monitor the effects of radiation?
The answer may lie in a fluid that has traditionally received little attention: gingival crevicular fluid (GCF). This fluid occupies the space between the teeth and gingiva and contains 8-oxo-dG, a by-product of DNA damage caused by oxidative stress. Importantly, 8-oxo-dG in GCF can be measured using ELISA, without requiring a biopsy or other invasive procedure.
From RSGM Prof. Soedomo to the Laboratory
The study involved 20 patients undergoing panoramic radiography at the radiology unit of RSGM UGM Prof. Soedomo: 10 underwent digital radiography and 10 underwent conventional radiography. All participants were 18 to 30 years old, systemically healthy, and free from periodontal tissue inflammation.
Samples were collected twice: before exposure and 10 days afterward for mucosal cell smears, and before and immediately after exposure for GCF. The mucosal smears were stained using a modified Feulgen-Rossenbeck method and examined under a microscope at 40× magnification. GCF was collected using a paper point inserted into the gingival sulcus for one minute and subsequently analyzed by ELISA to determine 8-oxo-dG levels.
The results were noteworthy. 8-oxo-dG levels increased after exposure with both techniques, although the increases did not reach statistical significance when analyzed separately. The more important finding was the correlation: 8-oxo-dG levels were significantly correlated with the number of micronuclei (r = 0.749, p < 0.01). The correlation was even stronger in the digital group (r = 0.879) than in the conventional group (r = 0.673).
“8-oxo-dG can be used as a parameter to detect the effects of radiographic exposure, and we strongly recommend that radiation protection be considered for patients undergoing panoramic radiography.”
This was the conclusion emphasized by Dr. drg. Rurie Ratna Shantiningsih, MDSc, and her research team.
Digital Is Safer, but Not Risk-Free
One notable finding was the difference between digital and conventional techniques. 8-oxo-dG levels before and after exposure were higher in the conventional group than in the digital group. The number of micronuclei was also significantly higher in the conventional group (p = 0.01). This is consistent with a well-established principle: digital panoramic radiography uses a lower radiation dose, resulting in less cellular impact.
However, the study also serves as a reminder that “lower” does not mean “zero.” The ALARA (As Low As Reasonably Achievable) principle emphasizes that even low radiation doses can potentially affect exposed tissues. The effects of panoramic radiation are stochastic, meaning that there is no clearly defined dose threshold that can be considered completely risk-free.
The implications are significant. If 8-oxo-dG in GCF is confirmed as a reliable biomarker, monitoring the effects of dental radiation could become considerably easier and more comfortable for patients. There would be no need for tissue biopsies or complex immunohistochemical procedures. A paper point inserted into the gingival sulcus for one minute, followed by ELISA analysis, could potentially be sufficient.
Of course, this study represents only an initial step. The sample size was limited, and the researchers acknowledged the need for further studies, including investigations into antioxidant agents that could provide additional protection against radiation-induced effects. According to the findings, oxidative stress caused by ionizing radiation may also be influenced by nutritional status and the availability of antioxidants in the body.
A panoramic X-ray may take only a few seconds. But the cells in a patient's gingiva may record its effects for much longer than we realize.
Source DOI: doi:10.1007/s11604-008-0232-0.
Authors: Anny Anggraini; drg. Achmad Zam Zam Aghasy, M.Kes.
Photo: Pexels