Delaying Intraoral Radiographs during the COVID-19 Pandemic: A Conundrum

Background. The COVID-19 pandemic has made dentists very assiduous about cross-infection during dental treatment, thereby delaying dental radiographs for treatment. However, patients needing dental emergency treatment in the ongoing pandemic require relevant intra/extraoral dental radiography for adequate diagnosis and treatment planning. Methods. This article is aimed at adding to the hot debate: Is delay for intraoral radiographs justified or a possible proxy? As a narrative review, it provides an insight into the reasons for delaying intra-oral dental radiographs during in the pandemic and options of the nontraditional radiographic techniques available until the pandemic subsides. Discussion and Conclusion. Cross-contamination concerns through respiratory droplets grow while using intraoral film holders that stimulate gag reflex, coughing, saliva secretion, and if proper disinfection protocols are not applied. Since the patients’ acquiring emergency dental treatment cannot be neglected, the return-to-work guidelines by the health regulatory bodies urge to prioritize extraoral radiographic imaging techniques to curb the infection, offering the best diagnostic efficacy. The dental professionals can consider cone-beam computed tomography (CBCT) scans and sectional dental panoramic radiographs (SDPRs), followed by a risk assessment for COVID-19, a safer modality in reducing cross-contamination and assuring an innocuous environment for both patient and coworkers.

Changes in the Oral Cavity in Menopausal Women—A Narrative Review

Oral health awareness during the menopausal period is essential to minimize the inevitable inconveniences which may occur due to hormonal changes. The decrease in estrogen hormone concentration impacts the oral mucosa in a similar way to the vaginal mucosa due to the presence of estrogen receptors in both of these structures. An estrogen deficiency also affects the maturation process of the oral mucosal epithelium and can lead to its thinning and atrophy, making it more susceptible to local mechanical injuries, causing a change in pain tolerance and problems in the use of removable prosthetic restorations. Mucosal epithelium during the menopausal period is more vulnerable to infections, candidiasis, burning mouth syndrome, oral lichen planus (OLP), or idiopathic neuropathy. Moreover, salivary glands are also hormone-dependent which leads to changes in saliva secretion and its consistency. In consequence, it may affect teeth and periodontal tissues, resulting in an increased risk of caries and periodontal disease in menopausal women. Due to the large variety of complaints and symptoms occurring in the oral cavity, menopausal women constitute a significant group of patients who should receive special preventive and therapeutic care from doctors and dentists in this particular period.

Salivary gland dysfunction and salivary redox imbalance in patients with Alzheimer’s disease

Alzheimer’s disease (AD) is associated with the deposition of β-amyloid in the brain. AD accounts for over 50% of cases of dementia which results from disturbances in redox homeostasis. Indeed, increased intensity of protein oxidation and nitration as well as lipid peroxidation is observed in brain areas with considerable amounts of amyloid plaques and neurofibrillary tangles. However, little is known about the oxidoreductive balance of salivary glands in AD patients. Therefore, the aim of this study was to evaluate the antioxidant barrier and oxidative/nitrosative stress biomarkers in stimulated saliva and blood of AD patients. The study was participated by 25 AD patients and 25 non-demented controls without neurological diseases or cognitive impairment, matched by age and gender to the study group. The number of patients was determined based on a previous pilot study (test power = 0.9). We found a significant decrease in the activity of erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx), increased activity of catalase (CAT) and reduced concentration of plasma non-enzymatic antioxidants (uric acid, UA and reduced glutathione, GSH). In contrast, in the stimulated saliva of AD patients we observed significantly decreased activity of all antioxidant enzymes (SOD, CAT and GPx) as well as concentration of GSH compared to the control group. The content of lipid (malondialdehyde, MDA) and protein (advanced oxidation protein products, AOPP; advanced glycation end-products, AGE) oxidation products as well as biomarkers of nitrosative stress (peroxynitrite, nitrotyrosine) was significantly higher in both saliva and plasma of AD patients compared to the controls. In AD patients, we also observed a considerable decrease in stimulated saliva secretion and salivary total protein content, and an increase in salivary β-amyloid concentration. In conclusion, AD results in redox imbalance towards oxidative reactions, both at the level of the oral cavity and the entire body. General redox balance disturbances do not coincide with salivary redox balance disturbances. Reduction in stimulated saliva secretion in AD patients reflects secretory dysfunction of the parotid glands.

Persistent Gustatory Dysfunction in COVID-19 Survivors: A Narrative Literature Review

Patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exhibit a diverse spectrum of clinical manifestations, some of which last for a long time, making a great impact on the healthcare of patients who recovered from coronavirus disease 2019 (COVID-19). Although taste disorders have been well-recognized to be closely associated with COVID-19, understanding of gustatory sequelae is relatively poor compared with oral symptoms in the early phase of COVID-19. The aim of this study was to characterize gustatory dysfunction in COVID-19 survivors by a narrative literature review of follow-up studies and to speculate the pathogenic mechanisms underlying such a persistent symptom. Scientific articles were retrieved by searching PubMed, LitCovid, ProQuest, medRxiv and bioRxiv from 1 April 2020 with a cut-off date of 10 September 2021. The follow-up time periods of the relevant 49 studies ranged from 4 weeks to 12 months. Results of the literature search indicated that ageusia, hypogeusia and/or dysgeusia persist in up to 45.0% of COVID-19 survivors and that the prevalence of these taste impairments varies depending on ethnicity, age, gender and disease severity of patients. Gustatory dysfunction can be detected at high frequency even one year after symptom onset. Persistence of gustatory dysfunction is pathogenically related to expression of SARS-CoV-2 cellular entry-relevant receptors in taste cells and neural cells, decreased saliva secretion, zinc deficiency, disturbed nervous system and inflammation associated with persistent SARS-CoV-2 infection. Given the long-term persistence of gustatory dysfunction in COVID-19 survivors, their discharge from hospital is not the end of disease. Careful attention should be continuously paid to taste perception of post-COVID-19 patients to recover the health-relating quality of life, which is required for health providers, especially dental professionals who not only may experience COVID-19 survivors but also can easily become aware of their taste abnormalities.

Differential activation of Ca2+ influx channels modulate stem cell potency, their proliferation/viability and tissue regeneration

Stem cells have indefinite self-renewable capability; however, factors that modulate their pluripotency/function are not fully identified. Here we show that store-dependent Ca2+ entry is essential for modulating the function of bone marrow-derived mesenchymal stem cells (MSCs). Increasing external Ca2+ modulated cell cycle progression that was critical for MSCs survival. Additionally, Ca2+ was critical for stem proliferation, its differentiation, and maintaining stem cell potential. Ca2+ channel characterization, including gene silencing, showed two distinct Ca2+ entry channels (through Orai1/TRPC1 or via Orai3) that differentially regulate the proliferation and viability of MSCs. Importantly, NFκB translocation, but not JNK/ERK into the nucleus, was observed upon store depletion, which was blocked by the addition of Ca2+ channel inhibitors. Radiation lead to a decrease in saliva secretion, decrease in acinar cell number, and enlarged ducts were observed, which were restored by the transplantation of stem cells that were propagated in higher Ca2+. Finally radiation showed a decrese in TRPC1 expression along with a decrese in AQP5, which was again restored upon MSC tranplantation. Together these results suggest that Ca2+ entry is essential for stem cell function that could be critical for regenerative medicine.

Care need and dry mouth as risk indicators for impaired taste and smell

To identify whether reduced saliva secretion or xerostomia symptoms are risk indicators for impaired taste and smell, depending on age and care needs. This cross-sectional study evaluated taste and smell in patients categorized into different age groups (<65> years) and different care need, with and without dry mouth. Of the 185 patients included, 119 were classified as “dry mouth” and 66 as “without dry mouth”. Overall, 103 (55.7%) were female and 37 (20%) needed care. There was no difference between “dry mouth” and “without dry mouth” regarding identification of odors or tastes, but a difference in the number of correctly identified odors and tastes in favor of “without care need” patients (p < 0.05). The ability to identify smells and tastes was negatively influenced by age, number of medications, and number of comorbidities, but subjective dry mouth had no impact. According to our results, subjective dry mouth is not a risk factor for an impaired ability to recognize smells and tastes. However, care need representing age, the number of medications taken, and the number of chronic comorbidities is a risk indicator.

Alzheimer’s Disease Results in Salivary Redox Imbalance Towards Oxidation Reactions

Alzheimer’s disease (AD) is associated with the deposition of β-amyloid in the brain. AD accounts for over 50% of cases of dementia which results from disturbances in redox homeostasis. Indeed, increased intensity of protein oxidation and nitration as well as lipid peroxidation is observed in brain areas with considerable amounts of amyloid plaques and neurofibrillary tangles. However, little is known about the oxidoreductive balance of salivary glands in AD patients. Therefore, the aim of this study was to evaluate the antioxidant barrier and oxidative/nitrosative stress biomarkers in stimulated saliva and blood of AD patients. The study was participated by 25 AD patients and 25 non-demented controls without neurological diseases or cognitive impairment, matched by age and gender to the study group. The number of patients was determined based on a previous pilot study (test power = 0.9). We found a significant decrease in the activity of erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx), increased activity of catalase (CAT) and reduced concentration of plasma non-enzymatic antioxidants (uric acid, UA and reduced glutathione, GSH). In contrast, in the stimulated saliva of AD patients we observed significantly decreased activity of all antioxidant enzymes (SOD, CAT and GPx) as well as concentration of GSH compared to the control group. The content of lipid (malondialdehyde, MDA) and protein (advanced oxidation protein products, AOPP; advanced glycation end-products, AGE) oxidation products as well as biomarkers of nitrosative stress (peroxynitrite, nitrotyrosine) was significantly higher in both saliva and plasma of AD patients compared to the controls. In AD patients, we also observed a considerable decrease in stimulated saliva secretion and salivary total protein content, and an increase in salivary β-amyloid concentration.In conclusion, AD results in redox imbalance towards oxidative reactions, both at the level of the oral cavity and the entire body. General redox balance disturbances do not coincide with salivary redox balance disturbances. Reduction in stimulated saliva secretion in AD patients reflects secretory dysfunction of the parotid glands.

Beyond Digestion: Can Animals Shape the Landscape According to Their Species–Specific Salivary Secretions?

Several functions are acknowledged for saliva secretion in different animal species following prehension and mastication of feed. Most of such are linked to the specific role of lubrication and softening of the bolus to allow taste perception and easy swallowing. Moreover, enzymatic components are produced in the saliva, some of which are destined to contribute to the digestion of different nutrients (to various extents according to animal species) and to exert antimicrobial activity (lysozyme). In addition, the buffering power and the virtuous recycle of water, electrolytes, and other metabolites are of particular importance for proper digestion and for nutrition–related aspects. Moreover, salivation appears to be involved in a number of other functions. Recent studies on salivary production and roles point to salivary glands as target organs of neuroendocrine regulation in response to many external stimuli coming from the outer world, for which feed still represents the chief external stimulus. Various animal species establish an adaptive strategy when coming into contact with different feeding stuffs and/or dietary substances by modifying both the composition and amount of saliva produced. In the light of recent updates, this review provides a focus on the functional roles of saliva secretions, showing the broad involvement of salivary response in several mechanisms beyond the digestive function and influencing feed selection.