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Emerging evidence shows that changes in the bone and its microenvironment following radiotherapy are associated with either an inhibition or a state of low bone formation. Ionizing radiation is damaging to the jawbone as it increases the complication rate due to the development of hypovascular, hypocellular, and hypoxic tissue. This review summarizes and correlates the current knowledge on the effects of irradiation on the bone with an emphasis on jawbone, as these have been a less extensively studied area. The stringent regulation of bone formation and bone resorption can be influenced by radiation, causing detrimental effects at structural, cellular, vascular, and molecular levels. It is also associated with a high risk of damage to surrounding healthy tissues and an increased risk of fracture. Technological advances and research on animal models as well as a few human bone tissue studies have provided novel insights into the ways in which bone can be affected by high, low and sublethal dose of radiation. The influence of radiation on bone metabolism, cellular properties, vascularity, collagen, and other factors like inflammation, reactive oxygen species are discussed. [ABSTRACT FROM AUTHOR]

The aim of this study was to define the acid-etching technique for bone samples embedded in polymethyl metacrylate (PMMA) in order to visualize the osteocyte lacuno-canalicular network (LCN) for scanning electron microscopy (SEM). Human jaw bone tissue samples (N = 18) were collected from the study population consisting of patients having received dental implant surgery. After collection, the bone samples were fixed in 70% ethanol and non-decalcified samples embedded routinely into polymethyl metacrylate (PMMA). The PMMA embedded specimens were acid-etched in either 9 or 37% phosphoric acid (PA) and prepared for SEM for further analysis. PMMA embedded bone specimens acid-etched by 9% PA concentration accomplishes the most informative and favorable visualization of the LCN to be observed by SEM. Etching of PMMA embedded specimens is recommendable to start with 30 s or 40 s etching duration in order to find the proper etching duration for the samples examined. Visualizing osteocytes and LCN provides a tool to study bone structure that reflects changes in bone metabolism and diseases related to bone tissue. By proper etching protocol of non-decalcified and using scanning electron microscope it is possible to visualize the morphology of osteocytes and the network supporting vitality of bone tissue. [ABSTRACT FROM PUBLISHER]

Saliva provides a valuable tool for assessing oral and systemic diseases, but concentrations of salivary components are very small, calling the need for precise analysis methods. In this work, Fourier transform infrared (FT-IR) spectroscopy using transmission and photoacoustic (PA) modes were compared for quantitative analysis of saliva. The performance of these techniques was compared with a calibration series. The linearity of spectrum output was verified by using albumin- thiocyanate (SCN-) solution at different SCN- concentrations. Saliva samples used as a comparison were obtained from healthy subjects. Saliva droplets of 15 μL were applied on the silicon sample substrate, 6 drops for each specimen, and dried at 37 °C overnight. The measurements were carried out using an FT-IR spectrometer in conjunction with an accessory unit for PA measurements. The findings with both transmission and PA modes mirror each other. The major bands presented were 1500-1750 cm-1 for proteins and 1050-1200 cm-1 for carbohydrates. In addition, the distinct spectral band at 2050 cm-1 derives from SCN- anions, which is converted by salivary peroxidases to hypothiocyanate (OSCN-). The correlation between the spectroscopic data with SCN- concentration (r>0.990 for transmission and r = 0.967 for PA mode) was found to be significant (P<0.01), thus promising to be utilized in future applications. [ABSTRACT FROM AUTHOR]

Background: The apical cell membrane of the oral mucosa adjacent to the saliva interface is thrown into membrane folds, termed microplicae (MPL) with variation in morphology. The present study classifies morphological changes undergone by MPL into qualitative and quantitative categories. Material and Methods: Oral mucosal specimens were obtained from 32 healthy patients. Half of each specimen was prepared routinely for light microscopy, and the other part for scanning and transmission electron microscopy. Different measurements of cell structure were presented: the density of MPL, the width and height of MPL, the width of furrows between two adjacent MPL and the distance of the centre of MPL. Morphometric measurements were obtained using a semiautomatic ImageJ analysis software (W Rasband, National Institutes of Health, Bethesda, MD). Results: Parallel and branching MPL was common observation in the area of lining mucosa and in the tongue between the filiform papillae. The density of MPL was higher in the cells of the buccal mucosa than in the cells of the tongue, 43.69 + 11.43% and 31.68 + 10.32%, respectively. The difference was significant ( p < 0.001). The width of MPL was 0.16 µm in cells of the buccal mucosa and 0.12 µm in cells of the tongue. Conclusions: Our findings support the idea that MPL structure is a determining factor for the functionality of the oral epithelium since the values of the MPL were kept relatively stable. The role of MPL structure of the oral mucosal cells is discussed. [ABSTRACT FROM AUTHOR]

Radiation exposure during the course of treatment in head and neck cancer (HNC) patients can induce both structural and biochemical anomalies. The present study is focused on utilizing infrared imaging for the identification of the minor biochemical alterations in the oral mucosa. Chemical maps generated using glycoprotein band indicates its differential distribution along the superficial layer. Spectra extracted from this layer suggests changes in overall nucleic acid and protein content in response to the therapeutic irradiation. Discrimination among control and irradiated groups have been achieved using principal component analysis. Findings of this preliminary study further support prospective utilization of Fourier Transform InfraRed (FTIR) imaging as a non-destructive, label-free tool for objective assessment of the oral mucosa in patient groups with or without radiation therapy. [ABSTRACT FROM AUTHOR]

Objective: The presence of a stable salivary pellicle (SP) is essential to provide a wet surface for the oral mucosal epithelia. The oral mucosa is covered by the SP which is suggested to be a mixed film of both salivary and epithelial components. Our aim was to analyse the presence of membrane-anchored mucin MUC1 in the oral mucosal epithelia. Desing: The presence of MUC1 was studied by immunohistochemical and immunoelectron microscopical methods in 19 buccal mucosal specimens. The localization and intensity of the epithelial expression were analyzed. Results: Strong staining of MUC1 was found in the epithelial cells of intermediate and superficial layers. Some basal cells were shown faint expression. In the intermediate and superficial layers, the MUC1 expression was seen mainly on the upper cell surface. Furthermore, the expression of MUC1 was noted in the cytoplasm near the nucleus and in the rough granules. By electron microscopy, extracellular domain of membrane-anchored molecules extruded about 15-30 nm above the cell surface in the apical cells of the oral epithelium. Immunoelectron microscopic examination shows that MUC1 is mainly localized in the plasma membrane of epithelial cells and also in small vesicles (75-100 nm) just below the plasma membrane. Conclusion: The membrane-anchored MUC1 is expressed in the superficial layer of the oral mucosal epithelium, especially on the upper surface of epithelial cells. MUCI may be the anchoring protein of the salivary pellicle stabilization. [ABSTRACT FROM AUTHOR]

Radiation exposure is a major health concern due to bone involvement including mandible, causing deleterious effects on bone metabolism, and healing with an increasing risk of infection and osteoradionecrosis. This study aims to investigate the radiotherapy-induced microstructural changes in the human mandible by scanning electron microscopy (SEM). Mandibular cortical bone biopsies were obtained from control, irradiated, and patients with osteoradionecrosis (ORN). Bone samples were prepared for light microscopy and SEM. The SEM images were analyzed for the number of osteons, number of Haversian canal (HC), diameter of osteon (D.O), the diameter of HC (D.HC), osteonal wall thickness (O.W.Th), number of osteocytes, and number of osteocytic dendrites. The number of osteons, D.O, D.HC, O.W.Th, the number of osteocytes, and osteocytic dendrites were significantly decreased in both irradiated and ORN compared to controls ( p  < .05). The number of HCs decreased in irradiated and ORN bone compared to the control group. However, this was statistically not significant. The deleterious effect of radiation continues gradually altering the bone quality, structure, cellularity, and vascularity in the long term (>5 years mean radiation biopsy interval). The underlying microscopic damage in bone increases its susceptibility and contributes further to radiation-induced bone changes or even ORN.

Objectives: The aim of this study was to assess the MUC1 expression in the oral epithelium of normal, oral epithelial dysplasia (OED), oral squamous cell carcinoma (OSCC), and irradiated oral epithelium (IROE) and its association with smoking habits in non-smokers and smokers., Design: Oral mucosal biopsies from controls, OED, OSCC, and IROE groups were obtained and categorized based on the smoking history as non-smokers, smoker I (25 pack-years), and smoker II (>25 pack-years). Immunohistochemical staining of MUC1 using human milk fat globule 1 (HMFG 1) antibody was performed, and the MUC1 score was calculated. The relation between MUC1 expression and clinicopathological findings was examined., Results: MUC1 staining of superficial oral epithelial cells with mild MUC1 score was detected in all control samples. The MUC1 staining extended from superficial to basal cell layer of oral epithelium with the increase in MUC1 score from moderate to strong in OED, OSCC, and IROE, and the difference was significant (p < 0.004, p < 0.002 and p < 0.004, respectively) compared to controls. A positive association between smoking and MUC1 score was observed within groups (p < 0.05)., Conclusion: The depolarization of MUC1 protein expression is associated with smoking habits in OED and OSCC. In the IROE, the radiation causes subcellular and molecular changes, observed as altered MUC1 expression and accelerated by smoking, furthermore, complicating the oral mucosal adaptation and progress to radiation-induced lesions as a delayed effect., Competing Interests: Conflict of Interest None declared., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: To investigate inter- and intra-individual variation in the levels and outputs (concentration multiplied by salivary flow rate) of salivary metabolites in patients with primary Sjögren's syndrome (pSS)., Methods: A total of 56 samples of stimulated saliva were collected from 14 female pSS patients during four laboratory visits within 20 weeks and analyzed using proton nuclear magnetic resonance spectroscopy. Single saliva samples from each of 15 controls were also analyzed., Results: Among 21 quantified metabolites, choline was significantly elevated in the pSS patients at each time point (P ≤ 0.015), taurine at the last three time points (P ≤ 0.013), alanine at the last two time points (P ≤ 0.007) and glycine at the last time point (P = 0.005). Inter-individual variation in metabolite concentrations was generally larger among the patients than among the controls, and significantly large variations were observed for glycine (P ≤ 0.007, all time points), choline (P ≤ 0.033, three last time points) and alanine (P = 0.028, baseline). Metabolite output analysis showed that choline had the lowest intra-patient variation., Conclusion: In spite of considerable intra- and inter-individual variation, levels and outputs of specific metabolites in patients with pSS differ from those in controls, and may be potentially applicable as new biological markers for monitoring of the response to treatment.

The analysis of the salivary metabolomic profile may offer an early phase approach to assess the changes associated with a wide range of diseases including head and neck cancer. The aim of the present study was to investigate the potential of nuclear magnetic resonance (NMR) spectroscopy for detecting the salivary metabolic changes associated with head and neck squamous cell carcinoma (HNSCC). Unstimulated whole-mouth saliva samples collected from HNSCC patients (primary tumour was located either in the larynx or in the oral cavity) and healthy controls were analysed by 1 H-NMR spectroscopy. Reliably identified salivary metabolites were quantified and the determined concentration values were compared group-wise using a Mann-Whitney U-test. Multivariate discrimination function analysis (DFA) was conducted to identify such a combination of metabolites, when considered together, that gives maximum discrimination between the groups. HNSCC patients exhibited significantly increased concentrations of 1,2-propanediol (P=0.032) and fucose (P=0.003), while proline levels were significantly decreased (P=0.043). In the DFA model, the most powerful discrimination was achieved when fucose, glycine, methanol and proline were considered as combined biomarkers, resulting in a correct classification rate of 92.1%, sensitivity of 87.5% and specificity of 93.3%. To conclude, NMR spectrometric analysis was revealed to be a feasible approach to study the metabolome of saliva that is sensitive to metabolic changes in HNSCC and straightforward to collect in a non-invasive manner. Salivary fucose was of particular interest and therefore, controlled longitudinal studies are required to assess its clinical relevance as a diagnostic biomarker in HNSCC.

Fissured tongue (FT) is a condition frequently seen in the general population. Clinically, FT is characterized by grooves that vary in depth and are noted along the dorsal and/or dorsolateral aspects of the tongue. Furthermore, FT presents many enlarged, smooth filiform papillae and subepithelial inflammatory infiltration. Despite of many studies, the etiology of FT remains obscure. FT is believed to be a congenital anomaly associated with several disorders and with geographic tongue (GT). We hypothesize that FT is not a congenital anomaly, and FT with swollen filiform papillae may represent edema in the subepithelial tissue of the tongue. According to the literature, the difference in prevalence among different age groups indicates that FT is not a congenital disorder. FT appears to occur more commonly in adults, and it is very rare or not at all in children younger than 10 years old. An association between FT and GT is well established in the literature, supporting the results of previous authors suggesting that FT might be a consequence of GT. The most remarkable finding in the region of swollen papillae of FT samples has been the subepithelial infiltrates of polymorphonuclear leucocytes and lymphocytes causing the subepithelial edema. The clinically visible grooves and large edematic papillae clustered on the region of the fissures might be caused by the inflammation and edema underneath the epithelium. In the future, FT and GT must be researched together as two different entities of the same disease so that GT is a prestage of FT. The diagnosis of FT must be taken to consideration whether the tongue surface have smooth and swollen papillae or normal-appearing filiform papillae., (Copyright © 2014 Elsevier Ltd. All rights reserved.)