Unraveling the Reaction Mystery of Li and Na with Dry Air.

Li and Na metals with high energy density are promising in application in rechargeable batteries but suffer from degradation in the ambient atmosphere. The phenomenon that in terms of kinetics, Li is stable but Na is unstable in dry air has not been fully understood. Here, we use in situ environmental transmission electron microscopy combined with theoretical simulations and reveal that the different stabilities in dry air for Li and Na are reflected by the formation of compact Li2O layers on Li metal, while porous and rough Na2O/Na2O2 layers on Na metal are a consequence of the different thermodynamic and kinetics in O2. It is shown that a preformed carbonate layer can change the kinetics of Na toward an anticorrosive behavior. Our study provides a deeper understanding of the often-overlooked chemical reactions with environmental gases and enhances the electrochemical performance of Li and Na by controlling interfacial stability.

Lessons learned in the practice of community-based participatory research with community partner collaboration in study design and implementation: the community scientist model.

Engagement of community participation is an innovative driver of modern research. However, to benefit the communities being studied, it is imperative to continuously evaluate ethical considerations, the relationship dynamic between researchers and community members, and the responsiveness of research teams to the needs and preferences of communities. Northwestern University's Center for Health Equity Transformation founded a community scientist program in 2018 that implemented a study using the Community-Based Participatory Research (CBPR) model. This project is an ongoing study of heavy metal exposure by geographic location in Chicago. Community scientists from various backgrounds, communities, and organizations formed an advisory panel, partnering with the cancer research team. This commentary describes lessons learned in structuring meaningful community involvement and benefit in CBPR, with a focus on three lessons learned that relate to ethics, relationships, and responsiveness. Our findings lay new groundwork for iteratively shaping best practices in CBPR.

Gene Expression and Early Radiation Response of Two Distinct Neuroblastoma Cell Lines.

INTRODUCTION: Neuroblastoma is one of the most common childhood cancers with one of the lowest survival rates, accounting for 15% of childhood cancer mortality. Approximately half of children treated for high-risk neuroblastoma will relapse following remission, while another 15% of patients do not respond to initial treatment. External beam radiation is infrequently used for treatment of pediatric cancer such as neuroblastoma, typically reserved for palliative care in patients with aggressive metastatic disease who fail to respond to alternative treatments. Understanding effects of radiation on neuroblastoma cells could improve efficacy of this final means of therapy to decrease tumor burden and stabilize the disease. METHODS: In this study, we found that two microRNAs with opposite functions were expressed in two neuroblastoma cell lines with marked differences in radiosensitivity. Clonogenic assays were used to evaluate the radiation responses for these 2 cell lines, designated SK-N-AS and SK-N-DZ; cells were then irradiated at doses that cause 90% cell killing based on clonogenic assay and their RNA isolated and subjected to microarray analysis. In addition, cells were transfected with pre-miRNA constructs that led to overexpression of microRNAs miR-34a and miR-1228 to determine possible microRNA regulation of radiation response. RESULTS: Statistically significant differences were detected for expression of several thousand genes when the 2 cell lines were compared with each other. In comparison, radiation exposure resulted in only minor gene expression differences of less than 2-fold at the 1 h postirradiation timepoint in both cell lines. Overexpression of miR-34a and miR-1228 in either cell line did not alter this outcome. DISCUSSION: While these two neuroblastoma cell lines are phenotypically diverse and gene expression differences between them are extensive, we observed that the regulation of gene expression in both cell lines is in a stable equilibrium at early timepoints after exposure to ionizing radiation.

Determining the Impact of the COVID-19 Pandemic on Dental Care in the Serbian Adult Population: An Online Questionnaire-Based Study.

BACKGROUND Emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 virus) could lead to an increase in dental anxiety, avoidance of dental visits, and general neglect of oral health. This online questionnaire-based study conducted in April and May of 2021 in Serbia aimed to determine the impact of the coronavirus disease 2019 (COVID-19) pandemic on dental care. MATERIAL AND METHODS The study included 2060 adult citizens of the Republic of Serbia who participated in an anonymous online questionnaire based on a 5-point Likert scale. Data were collected on dental care routine prior to and during the pandemic, and the fear of negative consequences for oral health. The results were statistically analyzed using descriptive statistics, Pearson's correlation coefficient, ANOVA, and the paired t test. RESULTS Approximately one-fifth of the respondents postponed dental visits during the pandemic. Concern about postponing dental treatment was expressed by more than one-half of the respondents (57.1%), while 21.4% thought that they were already experiencing the consequences. Avoidance of preventive examinations and improvement of oral hygiene are more common among the elderly compared to younger respondents (P=.000). CONCLUSIONS The COVID-19 pandemic did not significantly affect the habit of avoiding dental interventions due to fear, but it did lead to part of the population completely avoiding even urgent dental interventions during the peak of the pandemic, and opting for tooth extraction rather than treatment. The strongest impact on dental care in the pandemic was among people over 64 years old.

Effects of Autoclave Sterilization on Cyclic Fatigue Resistance in 5 Types of Rotary Endodontic Instruments: An In Vitro Study.

BACKGROUND Rotary endodontic instruments are increasingly used in root canal treatment and have replaced stainless steel manual files. Cyclic fatigue is the cyclic loading of stress to produce deformation or fracture. This study aimed to evaluate and compare the effects of autoclave sterilization on cyclic fatigue in 5 types of rotary endodontic instruments. MATERIAL AND METHODS ProTaper Universal, BioRace, ProTaper Next, Twisted File, and HyFlex CM instruments were included in this study. Each type included 96 instruments, divided into 4 groups according to the number of sterilization cycles (0, 1, 3, 5). After sterilization, each group of instruments was divided into 2 subgroups and tested for cyclic fatigue in 2 simulated canals (45 degrees both and 2 radii, 2 mm and 5 mm). The number of cycles to failure (NCF) was calculated, and statistical analyses were carried out using the t test, Mann-Whitney U test, and ANOVA, followed by the Tukey post hoc test (p<0.05). Fracture surfaces were analyzed using scanning electron microscopy (SEM). RESULTS Within the group of non-sterilized instruments, ProTaper Universal showed significantly lower resistance to cyclic fatigue compared to the other types of instruments (p<0.001). After repeated sterilization, a significantly higher mean of NCF was observed for BioRace (p<0.001), ProTaper Next (p<0.001), Twisted File (p<0.001), and HyFlex CM (p<0.001) compared to ProTaper Universal. The resistance of HyFlex CM was significantly higher compared to the other types of instruments (p<0.001). CONCLUSIONS The findings from this study showed that autoclave sterilization of newer rotary endodontic instruments could increase resistance to cyclic fatigue.

Control of GM-CSF-Dependent Dendritic Cell Differentiation and Maturation by DEF6 and SWAP-70.

Although GM-CSF has been widely used in dendritic cell (DC) research, the mechanisms, factors, and signals regulating steady-state differentiation and maturation of GM-CSF-dependent DCs are insufficiently known. We found that the absence, individually or combined, of the related proteins DEF6 and SWAP-70 strongly enhances differentiation of murine GM-CSF-derived DCs. Contrasting SWAP-70, control through DEF6 does not depend on RHOA activation. DEF6 deficiency leads to expression of the DC-specific transcription factor ZBTB46 and prolonged STAT5 activation in GM-CSF cultures. SWAP-70 and DEF6-mediated restriction of DC differentiation converges mechanistically at the NF-κB pathway. DEF6 acts at early stages of DC differentiation in CD115-cKIT+ myeloid DC progenitors, whereas SWAP-70 acts subsequently. SWAP-70 and DEF6 regulate steady-state DC cytokine expression as well as in vivo accumulation in lymphatic tissue of migratory DCs. Our studies thus elucidate previously unknown roles of two closely related factors with distinct and complementary activities in DC differentiation and steady-state DC function.

COVID-19: Another Cause of Dental Anxiety?

BACKGROUND Fear has always been closely linked to dentistry but it could be intensified by the objective risks imposed by the pandemic. The objective of this study was to determine the profile of the frightened dental patient during the COVID-19 pandemic and determine measures taken by dentists to reduce fear and increase security among their patients. MATERIAL AND METHODS An anonymous online survey was conducted between March 15 and April 15, 2021. The respondents were 2060 adult citizens of the Republic of Serbia. In addition to demographic data, data related to the COVID-19 pandemic, dental fear, and attitudes and fear of dental interventions during the ongoing pandemic were compiled. The data were analyzed using descriptive statistics: the chi-square test and Pearson's coefficient. RESULTS Seventy percent of the respondents felt some level of fear of the ongoing pandemic, 50% felt fear of going to a dentist during the pandemic, 20% considered a dental office a hotspot for the transmission of SARS-CoV-2, and 43% would visit their dentist only in the case of emergency. CONCLUSIONS The COVID-19 pandemic has affected the attitudes and behavior of people pertaining to visits to dental offices. Identifying frightened patients and their opinions and fears at this challenging time would make it easier for dentists to include protocols in their everyday practice to increase a sense of security among their patients, such as implementing preventive measures in front of the patients, ensuring an empty waiting room, and providing telephone consultations.

Solid Electrolyte Interphase Evolution on Lithium Metal in Contact with Glyme-Based Electrolytes.

The formation of a stable solid electrolyte interphase (SEI) is a prerogative for functional lithium metal batteries. Herein, the formation and evolution of such SEI in contact with glyme-based electrolytes is investigated under open circuit voltage and several constant current cycles. An important conclusion of the study is that Lix Sy species are nonbeneficial SEI components, compared to the Li3 N counterpart. In addition, chemical (X-ray photoelectron spectroscopy, XPS) and electrochemical (impedance spectroscopy) evolution of SEI under galvanostatic conditions are comprehensively tracked.

Maintenance phase treatment of psychotic disorders in outpatients from Serbia - focus on long-term benzodiazepine use.

Introduction: Prescribing trends in maintenance therapy of patients with primary psychotic disorders (PSD) may vary worldwide. Present study aimed to investigate prescription patterns in a sample of outpatients with PSD from Serbia.Methods: In a sample of 73 PSD outpatients we analysed the rate of antipsychotic polypharmacy and psychotropic polypharmacy, concomitant continual benzodiazepine use, and associations between therapy, psychotic symptoms and quality of life.Results: Maintenance therapy (median daily dose 321 mg of chlorpromazine equivalents) predominantly consisted of monotherapy with second generation antipsychotics (45.2%), followed by antipsychotic polypharmacy based on first and second generation combination (25.0%). The median number of psychotropic drugs was 3. Benzodiazepines were continually prescribed to more than 60% of patients (mean daily dose 2.9 ± 2.0 mg lorazepam equivalents). Patients with benzodiazepine use had significantly more psychotropic medications and more antipsychotic polypharmacy, poorer quality of life and more severe psychopathology in comparison to another group.Conclusion: The present study demonstrated new information regarding the prescription patterns of psychotropic drugs in outpatients with PSD in Serbia, amplified with clinically relevant information. This study also revealed distinct prescription patterns concerning antipsychotic/benzodiazepine polypharmacy. Overall, such findings are likely to contribute to improving clinical practice and care for patients with PSD in general.KeypointsPresent exploratory research aimed to elucidate trends of antipsychotics polypharmacy and concomitant use of psychotropic medications including benzodiazepines in the maintenance treatment of outpatients with schizophrenia and other psychotic disorders, amplified with clinically relevant information (symptoms and quality of life).'Antipsychotic (AP) polypharmacy' was defined as concurrent use of more than one AP for at least 1 month; 'Psychotropic polypharmacy' was defined as the combination of AP and a different class of psychotropic drugs medication for at least one month.The median number of prescribed psychotropic drugs was 3 (mean 3.1 ± 1.1) and the average AP daily dose was moderate (median 321 mg of chlorpromazine equivalents). However, the rates of AP polypharmacy (45.2%) and benzodiazepine prescription on a continual basis (>60%) found in our sample could be considered relatively high.Outpatients with higher AP daily dose and higher BPRS symptom score were receiving more benzodiazepines.For improvement of the local, as well as general clinical practice and care for patients with psychotic disorders, and for education in psychiatry, such analyses need to be done on a regular basis and on larger samples.

ER stress is not elevated in the 5XFAD mouse model of Alzheimer's disease.

Alzheimer's disease mouse models that overexpress amyloid precursor protein (APP) and presenilin 1 (PS1) form ß-amyloid (Aß) plaques, a hallmark Alzheimer's disease lesion. It has been assumed that the neuroinflammation, synaptic dysfunction, neurodegeneration, and cognitive impairment observed in these mice are caused by cerebral Aß accumulation. However, it is also possible that accumulation of the overexpressed transmembrane proteins APP and PS1 in the endoplasmic reticulum (ER) triggers chronic ER stress and activation of the unfolded protein response (UPR). The 5XFAD mouse, a widely used amyloid pathology model, overexpresses APP and PS1, displays aggressive amyloid pathology, and has been reported to exhibit ER stress. To systematically evaluate whether 5XFAD mice have increased ER stress, here we used biochemical approaches to assess a comprehensive panel of UPR markers. We report that APP and PS1 levels are 1.8- and 1.5-fold, respectively, of those in 5XFAD compared with nontransgenic brains, indicating that transgenes are not massively overexpressed in 5XFAD mice. Using immunoblotting, we quantified UPR protein levels in nontransgenic, 5XFAD, and 5XFAD;BACE1-/- mice at 4, 6, and 9 months of age. Importantly, we did not observe elevation of the ER stress markers p-eIF2α, ATF4, CHOP, p-IRE1α, or BiP at any age in 5XFAD or 5XFAD;BACE1-/- compared with nontransgenic mice. Despite lacking Aß generation, 5XFAD;BACE1-/- mice still expressed APP and PS1 transgenes, indicating that their overexpression does not cause ER stress. These results reveal the absence of ER stress in 5XFAD mice, suggesting that artifactual phenotypes associated with overexpression-induced ER stress are not a concern in this model.

Neuroprotective Role of Selected Antioxidant Agents in Preventing Cisplatin-Induced Damage of Human Neurons In Vitro.

Chemotherapy-induced peripheral neuropathy (CIPN) is a side effect of platinum-based chemotherapy and decreases the quality of life of cancer patients. We compared neuroprotective properties of several agents using an in vitro model of terminally differentiated human cells NT2-N derived from cell line NT2/D1. Sodium azide and an active metabolite of amifostine (WR1065) increase cell viability in simultaneous treatment with cisplatin. In addition, WR1065 protects the non-dividing neurons by decreasing cisplatin caused oxidative stress and apoptosis. Accumulation of Pt in cisplatin-treated cells was heterogeneous, but the frequency and concentration of Pt in cells were lowered in the presence of WR1065 as shown by X-ray fluorescence microscopy (XFM). Transition metals accumulation accompanied Pt increase in cells; this effect was equally diminished in the presence of WR1065. To analyze possible chemical modulation of Pt-DNA bonds, we examined the platinum LIII near edge spectrum by X-ray absorption spectroscopy. The spectrum found in cisplatin-DNA samples is altered differently by the addition of either WR1065 or sodium azide. Importantly, a similar change in Pt edge spectra was noted in cells treated with cisplatin and WR1065. Therefore, amifostine should be reconsidered as a candidate for treatments that reduce or prevent CIPN.

Store depletion-induced h-channel plasticity rescues a channelopathy linked to Alzheimer's disease.

Voltage-gated ion channels are critical for neuronal integration. Some of these channels, however, are misregulated in several neurological disorders, causing both gain- and loss-of-function channelopathies in neurons. Using several transgenic mouse models of Alzheimer's disease (AD), we find that sub-threshold voltage signals strongly influenced by hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels progressively deteriorate over chronological aging in hippocampal CA1 pyramidal neurons. The degraded signaling via HCN channels in the transgenic mice is accompanied by an age-related global loss of their non-uniform dendritic expression. Both the aberrant signaling via HCN channels and their mislocalization could be restored using a variety of pharmacological agents that target the endoplasmic reticulum (ER). Our rescue of the HCN channelopathy helps provide molecular details into the favorable outcomes of ER-targeting drugs on the pathogenesis and synaptic/cognitive deficits in AD mouse models, and implies that they might have beneficial effects on neurological disorders linked to HCN channelopathies.

Vitamin D prevents cognitive decline and enhances hippocampal synaptic function in aging rats.

Vitamin D is an important calcium-regulating hormone with diverse functions in numerous tissues, including the brain. Increasing evidence suggests that vitamin D may play a role in maintaining cognitive function and that vitamin D deficiency may accelerate age-related cognitive decline. Using aging rodents, we attempted to model the range of human serum vitamin D levels, from deficient to sufficient, to test whether vitamin D could preserve or improve cognitive function with aging. For 5-6 mo, middle-aged F344 rats were fed diets containing low, medium (typical amount), or high (100, 1,000, or 10,000 international units/kg diet, respectively) vitamin D3, and hippocampal-dependent learning and memory were then tested in the Morris water maze. Rats on high vitamin D achieved the highest blood levels (in the sufficient range) and significantly outperformed low and medium groups on maze reversal, a particularly challenging task that detects more subtle changes in memory. In addition to calcium-related processes, hippocampal gene expression microarrays identified pathways pertaining to synaptic transmission, cell communication, and G protein function as being up-regulated with high vitamin D. Basal synaptic transmission also was enhanced, corroborating observed effects on gene expression and learning and memory. Our studies demonstrate a causal relationship between vitamin D status and cognitive function, and they suggest that vitamin D-mediated changes in hippocampal gene expression may improve the likelihood of successful brain aging.

Prevalence of Human Cytomegalovirus and Epstein-Barr Virus in Chronic Periapical Lesions.

OBJECTIVE: The aim of this study was to investigate the presence of human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) in the tissue of chronic periapical lesions, and to compare the results in relation to the symptoms of patients and the size of the lesion. METHODS: Periapical lesions analyzed in the study were collected from the roots of the teeth indicated for extraction. Samples were divided according to the symptoms into groups of symptomatic and asymptomatic, and according the size into groups of small and large lesions. Polymerase chain reaction was used to detect HCMV and EBV. The amplification was performed in a DNA Thermal Cycler (Hybaid). RESULTS: Symptomatic lesions were 7.68 times more likely to be infected with HCMV than asymptomatic lesions (p < 0.001). Large symptomatic lesions were 73.50 times more likely to harbor HCMV than small symptomatic lesions (p < 0.001). Large symptomatic lesions were 7.64 times more likely to be infected with EBV than small symptomatic lesions (p = 0.05). Large symptomatic lesions were 5.38 times more likely to harbor dual HCMV/EBV infection than small symptomatic lesions (p = 0.115). CONCLUSION: Detection of HCMV and EBV in the samples of periapical lesions suggests an important role of herpesviruses in periapical tissue destruction.

Lithium potential variations for metastable materials: case study of nanocrystalline and amorphous LiFePO4.

Much attention has been paid to metastable materials in the lithium battery field, especially to nanocrystalline and amorphous materials. Nonetheless, fundamental issues such as lithium potential variations have not been pertinently addressed. Using LiFePO4 as a model system, we inspect such lithium potential variations for various lithium storage modes and evaluate them thermodynamically. The conclusions of this work are essential for an adequate understanding of the behavior of electrode materials and even helpful in the search for new energy materials.

Erosive Effect of Different Soft Drinks on Enamel Surface in vitro: Application of Stylus Profilometry.

OBJECTIVE: To assess the erosive potential of various soft drinks by measuring initial pH and titratable acidity (TA) and to evaluate enamel surface roughness using different exposure times. MATERIALS AND METHODS: The initial pH of the soft drinks (group 1: Coca-Cola; group 2: orange juice; group 3: Cedevita; group 4: Guarana, and group 5: strawberry yoghurt) was measured using a pH meter, and TA was measured by titration with NaOH. Enamel samples (n = 96), cut from unerupted human third molars, were randomly assigned to 6 groups: experimental (groups 1-5) and control (filtered saliva). The samples were exposed to 50 ml of soft drinks for 15, 30 and 60 min, 3 times daily, during 10 days. Between immersions, the samples were kept in filtered saliva. Enamel surface roughness was measured by diamond stylus profilometer using the following roughness parameters: Ra, Rq, Rz, and Ry. Data were analyzed by one-way ANOVA, Tukey's post hoc and Student-Newman-Keuls post hoc tests. RESULTS: The pH values of the soft drinks ranged from 2.52 (Guarana) to 4.21 (strawberry yoghurt). Orange juice had the highest TA, requiring 5.70 ml of NaOH to reach pH 7.0, whereas Coca-Cola required only 1.87 ml. Roughness parameters indicated that Coca-Cola had the strongest erosion potential during the 15 min of exposure, while Coca-Cola and orange juice were similar during 30- and 60-min exposures. There were no significant differences related to all exposure times between Guarana and Cedevita. Strawberry yoghurt did not erode the enamel surface regardless of the exposure time. CONCLUSION: All of the tested soft drinks except yoghurt were erosive. Erosion of the enamel surfaces exposed to Coca-Cola, orange juice, Cedevita, and Guarana was directly proportional to the exposure time.

The Role of SOX2 and SOX9 Transcription Factors in the Reactivation-Related Functional Properties of NT2/D1-Derived Astrocytes.

Astrocytes are the main homeostatic cells in the central nervous system, with the unique ability to transform from quiescent into a reactive state in response to pathological conditions by reacquiring some precursor properties. This process is known as reactive astrogliosis, a compensatory response that mediates tissue damage and recovery. Although it is well known that SOX transcription factors drive the expression of phenotype-specific genetic programs during neurodevelopment, their roles in mature astrocytes have not been studied extensively. We focused on the transcription factors SOX2 and SOX9, shown to be re-expressed in reactive astrocytes, in order to study the reactivation-related functional properties of astrocytes mediated by those proteins. We performed an initial screening of SOX2 and SOX9 expression after sensorimotor cortex ablation injury in rats and conducted gain-of-function studies in vitro using astrocytes derived from the human NT2/D1 cell line. Our results revealed the direct involvement of SOX2 in the reacquisition of proliferation in mature NT2/D1-derived astrocytes, while SOX9 overexpression increased migratory potential and glutamate uptake in these cells. Our results imply that modulation of SOX gene expression may change the functional properties of astrocytes, which holds promise for the discovery of potential therapeutic targets in the development of novel strategies for tissue regeneration and recovery.

The only proposed T-cell epitope derived from the TEL-AML1 translocation is not naturally processed.

Adoptive therapy with T-cell receptor (TCR)-engineered T cells is a promising approach in cancer treatment. While usage of T cells specific for tumor-associated antigens (TAAs) can lead to serious side effects because of autoimmunity, targeting true tumor-specific mutations, such as the products of translocations in leukemias, should reduce such a risk. A potentially ideal target might be the chimeric protein TEL-AML1, which results from the chromosomal translocation 12;21 and represents the most common fusion gene in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Within the fusion region of TEL-AML1, a single epitope has been described by reverse immunology as immunogenic in HLA-A*0201 restriction settings. As a potential source of TCRs specific for this TEL-AML1 epitope, we have used mice expressing a human TCR-αß repertoire and human MHC class I. Surprisingly, we have found that, although a specific functional CD8(+) T-cell response against this peptide could be evoked, the described epitope was in fact not endogenously processed. Analyses done with a potent antigen-presenting cell line, as well as with purified human proteasomes, support the conclusion that this peptide cannot be proposed as a potential target in immunotherapy of ALL in HLA-A*0201-restricted fashion.

In vitro effect of beer, red and white wine on the morphology and surface roughness of human enamel.

BACKGROUND: Beer, red and white wine are acidic drinks whose frequent consumption can increase the risk of dental erosion. OBJECTIVES: To establish the effect of beer, red and white wine on the morphology and surface roughness (SR) of human enamel using different exposure times in a cyclic deand remineralization model in vitro. MATERIAL AND METHODS: The experiment included 33 surgically extracted impacted human third molars from patients aged 18-25 years. Enamel samples obtained by cutting crowns (n = 132) were submitted to alternate cycles of demineralization in (1) beer, (2) red wine, (3) white wine, (PC) positive control (orange juice), and remineralization in artificial saliva, which also represented a medium for negative control (NC). The experiment included cycles with different exposure times in alcoholic beverages and orange juice of 15, 30 and 60 min. Thus, 12 groups were formed (for each drink and each exposure time) containing 10 samples each, while the NC group consisted of 12 samples. Experiments were repeated 3x/day for 10 days. Enamel surface alterations were determined by stylus profilometry (average surface roughness (Ra)) and scanning electron microscopy (SEM). The Shapiro-Wilk test, independent samples Kruskal-Wallis test and multiple comparisons (all pairwise) were performed. RESULTS: With increasing exposure time, there was a positive correlation with Ra for white wineand orange juice-immersed samples (60 min compared to 15 min), which was also observed using SEM. There was no significant difference in the Ra between the other experimental samples for the same exposure time. CONCLUSIONS: This study confirms a certain erosive potential of beer, red and white wine, and a significant relationship with pH, titratable acidity (TA) and SR, but not with the exposure time for all tested alcoholic beverages. Moreover, differences among the ultrastructural patterns caused by alcoholic beverages over the enamel surface were observed.