The potential role of in vivo reflectance confocal microscopy for evaluating oral cavity lesions: a systematic review

State of the Art in the Diagnosis and Assessment of Oral Malignant and Potentially Malignant Disorders: Present Insights and Future Outlook-An Overview

Oral Potentially Malignant Disorder (OPMD) is a significant concern for clinicians due to the risk of malignant transformation. Oral Squamous Cell Carcinoma (OSCC) is a common type of cancer with a low survival rate, causing over 200,000 new cases globally each year. Despite advancements in diagnosis and treatment, the five-year survival rate for OSCC patients remains under 50%. Early diagnosis can greatly improve the chances of survival. Therefore, understanding the development and transformation of OSCC and developing new diagnostic methods is crucial. The field of oral medicine has been advanced by technological and molecular innovations, leading to the integration of new medical technologies into dental practice. This study aims to outline the potential role of non-invasive imaging techniques and molecular signatures for the early detection of Oral Malignant and Potentially Malignant Disorders.

Confocal microscopy in oral cancer and oral potentially malignant disorders: A systematic review

OBJECTIVE

To systematically identify and summarise current research on the utility of confocal microscopy in oral squamous cell carcinoma and oral epithelial dysplasia in oral potentially malignant disorders.

METHODS

Databases Medline, Embase, Evidence-Based Medicine, and Web of Science were searched with articles screened and included if their primary objective was the use of a confocal microscope in diagnosis of oral cancer or epithelial dysplasia, in vivo or ex vivo.

RESULTS AND DISCUSSION

Twenty-eight relevant studies were identified of which 21 studies included oral squamous cell carcinoma specimens. Fifteen studies included in vivo use. The studies included both qualitative and fluorescence confocal microscope and reflectance confocal microscope analysis along with quantitative analysis of carcinoma and dysplasia. Thirteen studies reported the predictive value of their confocal device in the diagnosis of dysplasia and carcinoma. The quantitative software-based studies show promise in objectifying the diagnostic process for identifying abnormalities within the microstructure of the oral mucosa.

CONCLUSIONS

There was heterogeneity in the criteria for diagnosis of dysplasia and oral squamous cell carcinoma with experience levels of assessors impacting method efficacy. Both qualitative and quantitative confocal assessment methodologies have been explored, the latter highlighting the potential of future machine-augmented diagnostic precision.

Salivary microRNAs as innovative biomarkers for early diagnosis of oral diseases: a comparison of conventional cigarette smokers and tobacco heating system 2.2 users

BACKGROUND

MicroRNAs (miRNAs) are considered valid prognostic and diagnostic biomarkers. The different miRNA expression profiles in cancer cells compared to normal cells make them potential biomarkers used for the early diagnosis of oral diseases. Following exposure to cigarette smoking, miRNA altered profile expression is associated with resistance mechanisms against anticancer therapies. Cellular models showed a reduced human gingival epithelium alteration after exposure to THS2.2 and a lower pathogenicity than 3R4F CS. The aim of the study was to compare the expression of saliva miRNA profile of THS2.2 and 3R4F CS users compared to patients not exposed to the risk factor and to identify and study the modulation of miRNAs associated with the development of oral diseases. In particular, we will focus on the analysis of a group of miRNAs know to be involved in the development of smoking-related diseases.

METHODS

The study will be performed in 18 months and dentists and biochemists will be involved in the different phases. To perform the study, healthy volunteers, including smokers of THS2.2 or 3R4F CS, will be enrolled.

RESULTS

The samples will be collected from 3 experimental groups, each consisting of 30 subjects: group 1 (no smoking subjects), group 2 (subjects exposed to THS2.2), group 3 (subjects exposed to 3R4F CS). The collection of the saliva sample will be conducted in a standardized way. Following the collection, saliva will be processed.

CONCLUSIONS

Previous studies have suggested that miRNAs are prognostic biomarkers for various smoking-related diseases. Based on the post-transcriptional regulation of some mRNAs connected to different oral pathologies, we expect a specific miRNA-mRNA interaction, which could be a starting point for the development of new possible diagnostic, therapeutic and prognostic approaches.

Personalized Medicine in Oral Oncology: Imaging Methods and Biological Markers to Support Diagnosis of Oral Squamous Cell Carcinoma (OSCC): A Narrative Literature Review

For decades, oral squamous cell carcinoma (OSCC) has been one of the most prevalent and mortal cancers worldwide. The gold standard for OSCC diagnosis is still histopathology but this narrative multidisciplinary review has the aim to explore the literature about conventional OSCC prognostic indicators related to the pTNM stage at the diagnosis such as the depth of invasion and the lymphovascular invasion associated with distant metastasis as indicators of poor life expectancy. Despite its multifactorial nature and recognizable precursors, its diagnosis at the early stages is still challenging. We wanted to highlight the importance of the screening as a primary weapon that a stomatologist should consider, intercepting all at-risk conditions and lesions associated with OSCC and its early stages. This narrative review also overviews the most promising imaging techniques, such as CT, MRI, and US-echography, and their application related to clinical and surgical practice, but also the most-investigated prognostic and diagnostic tissue and salivary biomarkers helpful in OSCC diagnosis and prognostic assessment. Our work highlighted remarkable potential biomarkers that could have a leading role in the future. However, we are still far from defining an appropriate and concrete protocol to apply in clinical practice. The hope is that the present and future research will overcome these limitations to benefit patients, clinicians, and welfare.

Teledentistry: Evaluation of Instagram posts related to bruxism

BACKGROUND

Instagram statistic has attracted roughly one billion, monthly active users. In 2021, Instagram belonged to the most popular social networks worldwide. It has been considered an effective tool that contributes to the contemporary sharing of information for raising public awareness while providing educational information. The growing presence of Instagram and frequent user engagement has made it a potentially effective platform for patient communication, seeking educational information, product information for consumers, and advertisements in the form of images and videos.

OBJECTIVE

To assess and compare the contents of Instagram posts by healthcare professionals (HP) and non-professional healthcare workers (NPHW) on bruxism and to assess public engagement with this content.

METHODS

Twelve "hashtag" terms linked to bruxism were searched. HP and NPHW analyzed the content of relevant posts for the presence of domains. Discourse analysis assessed the post quality for themes. We conducted the descriptive and univariate statistical analysis, whereas inter-rater reliability was tested using Cohen's kappa.

RESULTS

A total of 1184 posts were retrieved, with the majority uploaded by NPHW (622 posts). The posts by HPs were in text and image(s) format (53%) with the range of 25-1100 Instagram post "Likes." "Mouthguard" (90) % was the most frequently included domain posted by HP, followed by "treatment plan/pain management", and complaints of clicking or locking of TMJ" (84%). Greater number of domains (p= 0.03) were seen in the posts by NPHWs, compared to HP's having more bruxism-related content. The inter-rater reliability method (0.89) was used for the presence of domains.

CONCLUSION

NPHW uses Instagram more frequently to post bruxism-related information than HP. HPs must ascertain that the content posted by NPHW is relevant and the concerns addressed in posts are to the purpose.

The Role of Reflectance Confocal Microscopy in the Evaluation of Pigmented Oral Lesions and Their Relationship With Histopathological Aspects

ABSTRACT

Oral pigmentations are a heterogeneous group and can be the result of physiological activity of oral mucosal melanocytes, secondary to exogenous causes, associated with systemic or local diseases, or due to proliferative activity of melanocytes. Their diagnosis is critical because these lesions can be markers of internal diseases or, in the case of melanocytic proliferative processes, they may represent a malignant neoplasm. In the past decade, the use of reflectance confocal microscopy, a noninvasive imaging tool, has aided the analysis of such lesions, but the establishment of firm criteria in their evaluation is still lacking. This study evaluated a series of 19 cases of pigmented oral lesions and correlated the reflectance confocal microscopy findings with histopathological classical criteria. We found 13 cases of melanotic macule, 1 of them associated with Peutz-Jeghers syndrome and 2 with Laugier-Hunzinker syndrome; 1 melanocytic nevus; 2 lentigo maligna; 2 pigmented actinic cheilitis; and 1 case of postinflammatory pigmentation secondary to a lupus erythematosus oral discoid lesion. The main difference between benign and malignant lesions was the presence of atypical proliferation in lentigo maligna. Langerhans cells with thick dendritic processes, which may be present in other benign and inflammatory pigmentations is one of the main reasons for diagnostic pitfalls.

YoutubeTM Content Analysis as a Means of Information in Oral Medicine: A Systematic Review of the Literature

Background: Oral medicine represents a complex branch of dentistry, involved in diagnosing and managing a wide range of disorders. Youtube^TM offers a huge source of information for users and patients affected by oral diseases. This systematic review aims to evaluate the reliability of Youtube^TM oral medicine-related content as a valid dissemination aid. Methods: The MeSH terms “Youtube^TM” and “oral” have been searched by three search engines (PubMed, ISI Web of Science, and the Cochrane Library), and a systematic review has been performed; the PRISMA checklist has been followed in the search operations. Results: Initial results were 210. Ten studies definitely met our selection criteria. Conclusions: Youtube^TM represents a dynamic device capable of easy and rapid dissemination of medical-scientific content. Nevertheless, the most of information collected in the literature shows a lack of adequate knowledge and the need to utilize a peer-reviewing tool in order to avoid the spreading of misleading and dangerous content.

High-Definition Ultrasound Characterization of Squamous Carcinoma of the Tongue: A Descriptive Observational Study

Simple Summary

The application of high-frequency ultrasound in the oral cavity for malignant lesions is a growing trend. As with other parts of the body, this method could become routine in the future. With this in mind, this work aimed to characterize squamous tumors of the tongue ultrasonographically and added additional descriptive elements to the current literature.

Abstract

High-definition ultrasonography is a diagnostic tool that uses sound echoes to produce images of tissues and organs. In the head and neck region, ultrasounds have been used to diagnose different types of lesions. The intraoral approach was shown to be a real-time, non-invasive way to characterize oral lesions. The tongue is the most often examined region because of its accessibility. This observational study aimed to describe the qualitative characteristics of tongue squamous cell carcinoma images obtained with high-definition intraoral ultrasound by comparing them with the corresponding histopathological sample. Twenty patients were enrolled in this study. The scans of the lesions were carried out with an 18 MHz linear ultrasound probe following the long axis of the lesion. For each lesion, five frames were selected, on which descriptive analysis was performed. A histological sample was taken and then compared to the ultrasonographic acquisition. The sonographic appearance of the tissue layers has a good correlation between ultrasound and histological morphology, and it was easy to distinguish the tumor from the homogenous composition of the tongue tissues. Furthermore, a correlation between the structure by section and pattern of tumor margin features by ultrasound was obtained. Intraoral ultrasonography appears to be a promising technique in the non-invasive characterization of tongue squamous cell carcinoma. Further studies will be needed to improve the technique in terms of ergonomics and repeatability.

Noninvasive in vivo imaging of oral mucosa: state-of-the-art

Technological development has interested most of the dentistry's branches leading to the use of other medical technologies non previously involved in dental practice. This study aims to evaluate the potential role of non-invasive imaging techniques in oral pathology workflow. Optical coherence tomography has been described by several authors as a promising aid for differential diagnosis of autoimmune diseases and to detect epithelial subversion of the oral mucosa before the clinical manifestation of oral mucositis. High-frequency ultrasound offers the chance to assess lesional dimensions both in benign and malignant lesions with a high dimensional reliability compared with histopathology. Reflectance confocal microscopy seems to be helpful in the early detection of cytological changes due to its high resolution, suggesting a more interesting role in the analysis of malignant lesions. The study presented highlighted the potential role of noninvasive in vivo imaging although further studies are needed for the further validation of these techniques.

Noninvasive Imaging Methods to Improve the Diagnosis of Oral Carcinoma and Its Precursors: State of the Art and Proposal of a Three-Step Diagnostic Process

Simple Summary

Oral squamous cell carcinoma (OSCC) accounts for 90–95% of malignant tumors of the lip and oral cavity and is associated with high mortality in the advanced stages. Early diagnosis is a challenge for oral pathologists and dentists, due to the ambiguous appearance of early OSCC, which is often misdiagnosed, mistreated, and associated with diagnostic delay. The gold standards for OSCC diagnosis are biopsy and histopathological assessment, but these procedures are invasive and time-consuming. Adjunctive noninvasive techniques allow the definition of the malignant features of a suspicious lesion in real time and noninvasively, thus improving the diagnostic procedure. The present review aimed to focus on some of the main promising noninvasive imaging techniques, to highlight their perspective adoption in a three-step diagnosis, which is idealistically faster and better, as well as enables the patient’s compliance.

Abstract

Oral squamous cell carcinoma (OSCC) is the most prevalent form of cancer of lips and oral cavity, and its diagnostic delay, caused by misdiagnosis at the early stages, is responsible for high mortality ratios. Biopsy and histopathological assessment are the gold standards for OSCC diagnosis, but they are time-consuming, invasive, and do not always enable the patient’s compliance, mainly in cases of follow-up with the need for more biopsies. The use of adjunctive noninvasive imaging techniques improves the diagnostic approach, making it faster and better accepted by patients. The present review aims to focus on the most consolidated diagnostic techniques, such as vital staining and tissue autofluorescence, and to report the potential role of some of the most promising innovative techniques, such as narrow-band imaging, high-frequency ultrasounds, optical coherence tomography, and in vivo confocal microscopy. According to their contribution to OSCC diagnosis, an ideal three-step diagnostic procedure is proposed, to make the diagnostic path faster, better, and more accurate.

Algorithm to quantify nuclear features and confidence intervals for classification of oral neoplasia from high-resolution optical images

Purpose: In vivo optical imaging technologies like high-resolution microendoscopy (HRME) can image nuclei of the oral epithelium. In principle, automated algorithms can then calculate nuclear features to distinguish neoplastic from benign tissue. However, images frequently contain regions without visible nuclei, due to biological and technical factors, decreasing the data available to and accuracy of image analysis algorithms. Approach: We developed the nuclear density-confidence interval (ND-CI) algorithm to determine if an HRME image contains sufficient nuclei for classification, or if a better image is required. The algorithm uses a convolutional neural network to exclude image regions without visible nuclei. Then the remaining regions are used to estimate a confidence interval (CI) for the number of abnormal nuclei per   mm 2 , a feature used by a previously developed algorithm (called the ND algorithm), to classify images as benign or neoplastic. The range of the CI determines whether the ND-CI algorithm can classify an image with confidence, and if so, the predicted category. The ND and ND-CI algorithm were compared by calculating their positive predictive value (PPV) and negative predictive value (NPV) on 82 oral biopsies with histopathologically confirmed diagnoses. Results: After excluding the images that could not be classified with confidence, the ND-CI algorithm had higher PPV (65% versus 59%) and NPV (78% versus 75%) than the ND algorithm. Conclusions: The ND-CI algorithm could improve the real-time classification of HRME images of the oral epithelium by informing the user if an improved image is required for diagnosis.

Reflectance confocal microscopy characteristics of oral lichen planus: An analysis of 47 cases in a Chinese cohort

Reflectance confocal microscopy (RCM) is a non-invasive tool that provides real-time microscopic images and relatively high-resolution tissue images. This technique provides a link between clinical examination and histopathology. RCM has been used to detect skin diseases and has also recently been applied to diseases of the oral mucosa. The present study aimed to explore the features of oral lichen planus (OLP) using RCM. A total of 47 patients with OLP exhibiting a reticular pattern, were included in the present study. The lesion sites and healthy adjacent sites were examined using in vivo RCM, with the lesion being histopathologically confirmed after RCM examination. The confocal images were reviewed, and the features were described. Sensitivity and specificity analysis of the RCM features was also performed. RCM examination presented parakeratosis, acanthosis and connective tissue papillae disappearance, with the presence of large melanocytes and roundish inflammatory cell infiltration, as well as dilated vessels in the lesion tissue. The sensitivity and specificity of OLP for dorsal tongue lesions were not as satisfactory as those on other sites. The results implied that RCM may be a promising technique to detect OLP non-invasively in vivo.

Real Time In Vivo Confocal Microscopic Analysis of the Enamel Remineralization by Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP): A Clinical Proof-of-Concept Study

Enamel defects (EDs) are qualitative and/or quantitative disturbances of the dental surface. To date, the responsiveness to remineralizing treatments has been studied ex vivo, on dental sections from extracted teeth. The present research aims to establish if in vivo reflectance confocal laser scanning microscopy is able to visualize the changes in the enamel architecture on living teeth, before, during and after remineralizing treatments by casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). As proof-of-concept study, 17 consecutive children affected by EDs were enrolled and 38 EDs were considered. A CPP-ACP mousse was applied twice a week for 6 weeks and clinical and microscopic images were collected before, during and after the treatment for evaluating the changes occurred. For in vivo microscopic imaging, a reflectance confocal laser scanning microscope (RCM) for in vivo use was adopted. In this study RCM was proven to be able to visualize in vivo and at microscopic resolution the changes occurred during the remineralizing processes without needing for dental extractions and histopathological procedures. This in vivo RCM capability could encourage its clinical application in monitoring responsiveness to enamel therapies.

Intraoral confocal microscopy of suspicious oral lesions: a prospective case series

BACKGROUND

Oral squamous cell carcinoma (OSCC) accounts for more than 90% of oral epithelial malignancies and often arises from precursor lesions, whose diagnosis is based on biopsy and histopathology. In vivo reflectance confocal microscopy (RCM) images the vital tissues at microscopic resolution, well correlating with conventional histopathology, but it is poorly investigated in oral oncology. The present work aims to describe RCM cytoarchitectural findings in oral mucosae affected by OSCC and its precursors.

MATERIALS AND METHODS

A series of clinically suspected oral lesions underwent RCM imaging before conventional biopsy and histopathological assessment in order to identify features suggestive of tumoral changes. Sensitivity (SE), specificity (SP), positive and negative predictive values (PPV and NPV) of RCM compared to histopathology were calculated.

RESULTS

Totally, 30 sites in 20 patients were considered and clinically classified into 16 "leukoplakia"/" traumatism", nine erosive-ulcerative lesions, three verrucous lesions, and two healthy mucosae, as control. The histopathological "positivity," due to the presence of various degrees of dysplasia and/or neoplasia, was found in 11 lesions; the RCM "positivity" was referred to nine lesions reporting the RCM detection of polymorphism, multinucleated cells, irregular cellular maturation, altered nuclear/cytoplasm ratio, and abnormal blood vessels. After excluding three verrucous lesions from the RCM analysis, due to the low laser penetration through the hyperkeratotic layers, the results well correlated with histopathology, reporting 1.000 (SE), 0.933 (SP), 0.909 (PPV), and 1.000 (NPV).

CONCLUSION

RCM can reveal dysplastic/neoplastic signs occurring in oral lesions, thus supporting their diagnostic pathway.

Measurement of Oral Epithelial Thickness by Optical Coherence Tomography

Optical coherence tomography (OCT) is a real-time, in-situ, non-invasive imaging device that is able to perform a cross-sectional evaluation of tissue microstructure based on the specific intensity of back-scattered and reflected light. The aim of the present study was to define normal values of epithelial thickness within the oral cavity. OCT measurements of epithelial thickness were performed in 28 healthy patients at six different locations within the oral cavity. Image analysis was performed using Image J 1.52 software. The healthy epithelium has a mean thickness of 335.59 ± 150.73 µm. According to its location within the oral cavity, the epithelium showed highest values in the region of the buccal mucosa (659.79 µm) and the thinnest one was observed in the mouth’s floor (100.07 µm). OCT has been shown to be useful for the evaluation of oral mucosa in vivo and in real time. Our study provides reference values for the epithelial thickness of multiple sites within the oral cavity. Knowledge of the thickness values of healthy mucosa is, therefore, of fundamental importance.

Feasibility of a Video-Mosaicking Approach to Extend the Field-of-View For Reflectance Confocal Microscopy in the Oral Cavity In Vivo

BACKGROUND

Reflectance confocal microscopy (RCM) is a developing approach for noninvasive detection of oral lesions with label-free contrast and cellular-level resolution. For access into the oral cavity, confocal microscopes are being configured with small-diameter telescopic probes and small objective lenses. However, a small probe and objective lens allows for a rather small field-of-view relative to the large areas of tissue that must be examined for diagnosis. To extend the field-of-view for intraoral RCM imaging, we are investigating a video-mosaicking approach.

METHODS

A relay telescope and objective lens were adapted to an existing confocal microscope for access into the oral cavity. Imaging was performed using metal three-dimensional-printed objective lens front-end caps with coverslip windows to contact and stabilize the tissue and set depth. Four healthy volunteers (normal oral mucosa), one patient (with an amalgam tattoo) in a clinical setting, and 20 anesthetized patients (with oral squamous cell carcinoma [OSCC]) in a surgical setting were imaged. Instead of the usual still RCM images, videos were recorded and then processed into video-mosaics. Thirty video-mosaics were read and qualitatively assessed by an expert reader of RCM images of the oral mucosa.

RESULTS

Whereas the objective lens' native field-of-view is 0.75 mm × 0.75 mm, the video-mosaics display larger areas, ranging from 2 mm × 2 mm to 4 mm × 2 mm, with resolution, morphologic detail, and image quality that is preserved relative to that observed in the original videos (individual images). Video-mosaics in healthy volunteers' and the patients' images showed cellular morphologic patterns in the lower epithelium and at the epithelial junction, and connective tissue along with capillary loops and blood flow in the deeper lamina propria. In OSCC, tumor nests could be observed along with normal looking mucosa in margin areas.

CONCLUSIONS

Video-mosaicking is a reasonably quick and efficient approach for extending the field-of-view of RCM imaging, which can, to some extent, overcome the inherent limitation of an intraoral probe's small field-of-view. Reading video-mosaics can mimic the procedure for examining pathology: initial visualization of the spatial cellular and morphologic patterns of the tumor and the spread of tumor margins over larger areas of the lesion, followed by digitally zooming (magnifying) for closer inspection of suspicious areas. However, faster processing of videos into video-mosaics will be necessary, to allow examination of video-mosaics in real-time at the bedside. Lasers Surg. Med. 51:439-451, 2019. © 2019 Wiley Periodicals, Inc.

Raman spectroscopic analysis of the molecular composition of oral cavity squamous cell carcinoma and healthy tongue tissue

A Raman tissue spectrum is a quantitative representation of the overall molecular composition of that tissue. Raman spectra are often used as tissue fingerprints without further interpretation of the specific information that they contain about the tissue's molecular composition. In this study, we analyzed the differences in molecular composition between oral cavity squamous cell carcinoma (OCSCC) and healthy tissue structures in tongue, based on their Raman spectra. A total of 1087 histopathologically annotated spectra (142 OCSCC, 202 surface squamous epithelium, 61 muscle, 65 adipose tissue, 581 connective tissue, 26 gland, and 10 nerve) were obtained from Raman maps of 44 tongue samples from 21 patients. A characteristic, average spectrum of each tissue structure was fitted with a set of 55 pure-compound reference spectra, to define the best library of fit-spectra. Reference spectra represented proteins, lipids, nucleic acids, carbohydrates, amino acids and other miscellaneous molecules. A non-negative least-squares algorithm was used for fitting. Individual spectra per histopathological annotation were then fitted with this selected library in order to determine the molecular composition per tissue structure. The spectral contribution per chemical class was calculated. The results show that all characteristic tissue-type spectra could be fitted with a low residual of <4.82%. The content of carbohydrates, proteins and amino acids was the strongest discriminator between OCSCC and healthy tissue. The combination of carbohydrates, proteins and amino acids was used for a classification model of 'tumor' versus 'healthy tissue'. Validation of this model on an independent dataset showed a specificity of 93% at a sensitivity of 100%.

Non-invasive analysis of bleaching effect of hydrogen peroxide on enamel by reflectance confocal microscopy (RCM): study of series of cases

The aim of this study is to evaluate in vivo the effects of in-office tooth whitening hydrogen peroxide (HP) agent on enamel-microstructured surface by a reflectance confocal microscopy (RCM). Ten healthy volunteers assisted at the Dental School presenting teeth with vital pulp were selected. The 35% HP whiteness product was applied in two visits on discolored teeth, 1-week interval between, via 20-min applications. A commercially available hand-held RCM (Vivascope3000^®, Lucid, Rochester, NY, USA) was used to image in vivo the dental surface of the selected tooth of each volunteer. Twenty upper central incisors' vestibular surfaces were imaged, before bleaching (T0), immediately after (T1) and 1 week later (T2). The peculiar structure of the enamel was seen at T0. After bleaching, white reflective circular bodies were found all over the teeth surfaces, which disappear 1 week later (T2). When the HP gel^® was imaged, the same white circular areas were observed. Going deeper, the regular enamel architecture was preserved. Textural analysis of the images in T0 and T2 was performed: GLCM parameters were extracted. Mann-Whitney U test was performed to evaluate statistical differences between two groups of data (p > 0.05). Finally, 35 prisms were randomly selected from T0 and T2 image and diameters were measured; a paired t test was performed (p = 0.381). The RCM is a promisor tool for investigating the features of enamel in vivo, immediately after bleaching procedures, as well as longitudinally.

In vivo reflectance confocal microscopy of oral lichen planus

BACKGROUND

In vivo reflectance confocal microscopy (RCM) is an imaging technique that can virtually biopsy vital tissues, noninvasively and in real time. It results in horizontal virtual slices at a microscopic resolution that correlates well with conventional histopathology. Despite the widespread use of RCM in dermatology, it is still rarely applied to the study of oral pathologies. The aim of the present work is to describe RCM cellular and architectural findings in oral mucosae affected by oral lichen planus (OLP).

MATERIALS AND METHODS

A series of conventionally diagnosed OLP lesions underwent RCM imaging with a portable reflectance confocal microscope that could scan from the surface to the submucosa. The confocal findings were collected, described, and compared with the literature.

RESULTS

A total of 31 oral sites affected by OLP in 12 patients were considered. According to their clinical appearance, 22 lesions showed a reticular-plaque pattern, six lesions were mainly atrophic-erosive, and the remaining three presented a mixed pattern. RCM examination showed hypergranulosis, epithelial disarray, spongiosis, necrotic keratinocytes, epithelial and subepithelial inflammatory cell infiltration, and dilated vessels; all findings were in lichen planus, with differences noted between the "white" and "red" manifestations of this pathology.

CONCLUSIONS

The use of RCM in routine clinical oral pathology tests is recommended to avoid recurrence of OLP and changes in its responsiveness to therapy, thus limiting the need for biopsy of lesions suspected of tumoral changes.

An Overview on Current Non-invasive Diagnostic Devices in Oral Oncology

Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy, and despite advances in cancer therapies, the overall 5-year survival rate has remained below 50% over the past decades. OSCC is typically preceded by potentially malignant disorders (PMD), but distinguishing high-risk from low-risk PMD is challenging. In the last years, several diagnostic methods as light-based detection systems (LBDS) have been proposed to facilitate the detection of OSCC and PMD. Furthermore, the recent evolution of nanotechnology may provide new opportunities to detect PMD and OSCC at an early stage. Indeed, several preclinical studies showed the potential of nanotechnology to enhance diagnostic accuracy. For these reasons, it is fundamental to conduct studies to evaluate the efficacy of nanotechnology implementation in LBDS. The aim of this article is to review the current literature on LBDS and to provide a summary of the sensitivity and specificity of each technique, and possible future applications of nanotechnologies. The LBDS showed great potential for screening and monitoring oral lesions, but there are several factors that hinder an extensive use of these devices. These devices seem to be useful in assessing lesion margins that must be biopsied. However, to date, conventional oral examination, and tissue biopsy remain the gold standard for OSCC diagnosis. The use of nanotechnologies could be the next step in the evolution of LBDS, thus providing devices that can help clinicians to detect and better monitor oral lesions.

Nanotechnology: a promising method for oral cancer detection and diagnosis

Oral cancer is a common and aggressive cancer with high morbidity, mortality, and recurrence rate globally. Early detection is of utmost importance for cancer prevention and disease management. Currently, tissue biopsy remains the gold standard for oral cancer diagnosis, but it is invasive, which may cause patient discomfort. The application of traditional noninvasive methods-such as vital staining, exfoliative cytology, and molecular imaging-is limited by insufficient sensitivity and specificity. Thus, there is an urgent need for exploring noninvasive, highly sensitive, and specific diagnostic techniques. Nano detection systems are known as new emerging noninvasive strategies that bring the detection sensitivity of biomarkers to nano-scale. Moreover, compared to current imaging contrast agents, nanoparticles are more biocompatible, easier to synthesize, and able to target specific surface molecules. Nanoparticles generate localized surface plasmon resonances at near-infrared wavelengths, providing higher image contrast and resolution. Therefore, using nano-based techniques can help clinicians to detect and better monitor diseases during different phases of oral malignancy. Here, we review the progress of nanotechnology-based methods in oral cancer detection and diagnosis.

Advances in the use of reflectance confocal microscopy in melanoma

In vivo reflectance confocal microscopy (RCM) is a noninvasive high-resolution skin imaging tool that has become an important adjunct to clinical exam, dermoscopy and histopathology assessment, in the diagnosis and management of melanoma. RCM generates a horizontal view of the skin, whereby cellular and subcellular (e.g., nuclei, melanophages, collagen) structures, to the level of the upper dermis, are projected onto a screen at near-histological resolution. Morphologic descriptors, standardized terminology, and diagnostic algorithms are well established for the RCM assessment of melanoma, melanocytic, and nonmelanocytic lesions. Clinical applications of RCM in melanoma are broad and include diagnosis, assessment of large lesions on cosmetically sensitive areas, directing areas to biopsy, delineating margins prior to surgery, detecting response to treatment and assessing recurrence. This review will provide an overview of RCM technology, findings by melanoma subtype, clinical applications, as well as explore the accuracy of RCM for melanoma diagnosis, pitfalls and emerging uses of this technology ex vivo.

In vivo confocal microscopy analysis of enamel defects after orthodontic treatment: A preliminary study

After orthodontic treatment with fixed appliances, bonded brackets and residual adhesive must be removed. This procedure should lead to restitutio ad integrum of the enamel or, at least, restore the enamel surface as closely as possible to its pre-treatment conditions. The purpose of this study is the in vivo assessment at a microscopic resolution of enamel surfaces after bracket debonding while avoiding the tooth extraction. Nine orthodontic patients who had brackets removed at the conclusion of orthodontic treatment were enrolled. In vivo reflectance confocal microscopy imaging of dental enamel surface after debonding was performed for each patient. Eighteen upper incisors were analyzed, 10 in which the enamel demineralization appeared after the treatment and 8 in which the demineralization was present before the treatment. RCM analyses showed some speckled or roundish dark areas within the enamel. Moreover enamel alterations were detected at different levels of depth. The present in vivo microscopic study allowed for highlighting structural features in dental enamel, after debonding, at a microscopic resolution in real-time and in a non-invasive way, without the need for extraction or processing of the samples.