# Emergence of Nano-Dentistry as a Reality of Contemporary Dentistry
## 4 Discussion
### Nanotechnologies in Diagnosis  
Nanoparticles are used not only for the treatment and prevention of dental diseases, but also as agents for extra research methods. Thus, more recently, the latest word in dental technology was \"laser diagnosis\" of caries, based on the optical phenomenon of transillumination. Researchers from the University of Michigan [102] used fluorescent dioxide-labeled cations of 150 nm starch nanoparticles. When irrigating the oral cavity with a solution of such particles, the latter easily penetrated into the micropores of the foci of demineralization, which were then easily detected under the light of a standard light curing halogen lamp. The technology described in 2017 allows detection of actively occurring superficial caries in the early stages of pathogenesis.  
Molecular Imaging Optical coherence tomography (OCT) it is a direct simulation of ultrasound, that is based on low-coherence interferometry, typically employing near-infrared light. OCT shows enormous potential for its application in more effective diagnosis and therapy of caries and erosive tooth wear. This technique is advantageous in qualitative assessment of pit and fissure sealing as well as providing great potential for imaging the outline form of the pulp chamber: pulp horns can be visualized during dental procedures and accidental pulp exposure can be avoided [103].  
Nanotechnology is a useful tool for cancer detection and disease monitoring, and also increases the possibility of specific targeted cancer therapy [104].  
OCT is used not only in caries diagnostics but also for oral cancer screening and monitoring. The main type of malignant neoplasm of the oral cavity is a squamous cell carcinoma of the oral cavity, which accounts for more than 90% of all cancers of the oral cavity. Squamous cell carcinoma is an aggressive cancer that has a poor prognosis and a high recurrence rate, which can even lead to death.  
With the development of nanotechnology, different types of nanoparticles came into use as specific contrast agents for magnetic resonance imaging, optical coherence tomography, etc. [PERSON] et al. created a nanoagent that is a combination of folate preconjugated chitosan and poly (magnetic lactic with glycolide) nanoparticles for simultaneous cancer therapy and a contrast agent for magnetic resonance imaging at the same time. Oral cancer cells with positive folic acid receptors showed increased uptake of nanoparticles and caused a significant increase in cytotoxicity [105].  
The gold nanoparticles are promising contrast agents for OCT due to biocompatibility; they can provide localized surface plasmon resonances at wavelengths of near-infrared radiation, which avoids the predominant absorption in tissues [106].  
Photoacoustic (PA) imaging is a new non-invasive technique of optical diagnostic technology. Near-infrared absorbing organic nanoparticles are used in PA imaging applications. Photoacoustic waves generated by the laser pulse are then converted into photoacoustic images. Photoacoustic images have improved image depth in comparison to conventional optical images. Organic nanoparticles with their exclusive benefits can play an important role in advancing PA molecular imaging in preclinical investigation and clinical use [107].  
The nano-based single biomarker method is used to detect oral cancer [108]. Investigation of tumor molecular biomarkers--such as tumor necrosis factor-alpha (TNF-\(\alpha\)), vascular endothelial growth factor, and interleukin 6 (IL 6)--gives great promise for early cancer detection. The research revealed TNF-\(\alpha\) by the method of gold protein chips using fluorescence microscopy of complete internal reflection [109].  
Despite of a wide range of benefits of nanoparticle application, there is a disadvantage of cytotoxicity that is seen only in higher concentrations. The cytotoxicity depends on the size--selective difference [110; 111; 112]. Therefore, new studies aimed at producing safe and biocompatible materials are needed [113; 114].