Zoran Mandinic

Elevated fluoride (F−) concentrations in the environment are a real-case scenario that could negatively affect various tissues. Therefore, the current in vivo study evaluated subacute (28 days) F−toxicity through the benchmark dose-response (BMD) approach in spleen tissue. Male Wistar rats were allocated into six groups (n = 5): a control group (tap water) together with five groups that were exposed to increasing F− concentrations (10, 25, 50, 100, and 150 mg/L sodium-fluoride (NaF)) ad libitum. Spleen tissue was prepared for copper (Cu), iron (Fe) and DNA damage (comet assay) determination. BMD methodology for the external and internal F−dose-response relationships was obtained via PROASTweb 70.1 software. The results showed that F−caused a significant increase in DNA damage in all experimental groups. No significant changes were observed for Cu and Fe levels. The dose-dependent alterations were confirmed for decreasing Cu levels. The presented data provide important findings on an unexplored dose-dependent relationship between F−exposure and possible toxicity mechanisms in the spleen tissue.

The dose–response relationship for fluoride (F⁻) exposure remains largely unexplored. Hence, the current study assessed the hepatotoxic and nephrotoxic effects of subacute exposure (28 days) to increasing F⁻ concentrations in Wistar rats via the benchmark dose (BMD5) method. Thirty male rats were assigned to six groups (n = 5): a control group (tap water) along with five groups that received F⁻ via drinking water at increasing concentrations (10, 25, 50, 100, and 150 mg/L). F⁻ toxicity was determined via water intake, weight gain, histological analyses, redox status, and essential element levels. PROASTweb 70.1 software was utilized to investigate the external and internal F⁻ dose–response relationships. Specified major cytoarchitecture damage and superoxide anion (O₂·⁻), total oxidative status (TOS), superoxide dismutase (SOD) activity, total thiol groups (SH), and advanced oxidation protein product (AOPP) level alterations were detected in both sets of tissues. Moreover, F⁻ caused an imbalance in copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn). The most sensitive parameters were O₂·⁻ (0.06 mg F⁻/kg) in the liver and AOPP (6.5 × 10⁻⁶ mg F⁻/L) in the kidneys. These findings contribute to the limited risk assessment of fluorides and highlight the dose-dependent relationship between redox status parameters and bioelements in the liver and kidneys.

Background/Objectives: Dental caries, one of the most common oral diseases worldwide, represents a major public health concern. Contemporary dentistry has established several non-invasive approaches and resin infiltration, as a micro-invasive path, in the treatment of white spot lesions (WSLs). This study aimed to evaluate the effect of different WSL treatments on enamel surface microhardness. Materials and Methods: Seventy-five intact human premolars extracted upon orthodontic indication and the demineralizing solution composed of acetic acid, monopotassium phosphate and calcium chloride with pH = 4.4 and exposure time 96 h were used. The samples were randomly divided into five groups (n = 15): I—intact enamel (control group); II—artificial white spot lesion; III—artificial WSL treated with fluoride varnish; IV—artificial WSL treated with casein phosphopeptide—amorphous calcium phosphate (CPP-ACP) paste; V—resin-infiltrated artificial WSL. The surface microhardness was determined using the Oliver–Pharr method and a spherical indenter (Shimadzu Indenter, Kyoto, Japan). One-way analysis of variance (ANOVA) followed by a Post Hoc test (Bonferroni) was used with a level of significance set at p < 0.05. Results: Resin-infiltrated white spot lesions showed comparable microhardness mean value as the control group: 68.23 (±21.45) and 63.57 (±18.89), respectively (p > 0.05). Also, resin infiltration increased enamel microhardness compared to WSL values, with a statistically significant difference (p < 0.05). Fluoride varnish and CPP-ACP treatment resulted in equivalent values (50.84 ± 14.35 and 50.99 ± 15.31, respectively). Conclusions: Different WSL treatments (fluoride varnish, CPP-ACP and resin infiltration) produced comparable enamel microhardness values. Among the tested agents, resin infiltration resulted in higher microhardness values, while fluoride varnish and CPP-ACP demonstrated equivalent outcomes.

Background and Objectives: Caries development is associated with poor oral hygiene, inadequate dietary habits, quantitative and qualitative food content, and a high level of bacterial plaque. Physical and chemical changes in saliva composition and particularly changes in its buffering capability play a significant role in caries development. This study aimed to determine the predictors of poor oral health among a sample of second-year dental students. Materials and Methods: The oral health of students was estimated with clinical examination and the DMFT index. The interview included questions about demographics status (gender, age), a dietary habits questionnaire, questions about oral hygiene, and a demonstration of tooth brushing technique. Unstimulated saliva samples were collected to measure buffering capacity and pH. Results: Almost half of the students have a low level of caries experience (46.7%), followed by a slightly smaller number having a medium level (41.3%), while one in eight students (12.0%) demonstrates a high level of caries experience. Male students have a statistically higher DMFT index 5.7 ± 1.2 than female participants 4.5 ± 0.5 (p = 0.036). Significant predictors for the DMFT index score in students were milk [β-coefficient = −0.338, p = 0.011] and yoghurt [β-coefficient = 0.284, p = 0.040] consumption. All students brushed their teeth two or more times during the day, usually after waking up before breakfast and before bedtime. Most students (85.3%) apply the proper tooth brushing technique, with female students applying it more frequently (p = 0.038). The mean salivary pH was 6.9, while the mean buffer capacity was 5.8. Female respondents have a statistically lower buffer capacity (5.8 ± 0.5) than male respondents (6.1 ± 0.4) (p = 0.047). Conclusions: Dentistry students are introduced to good oral hygiene habits, especially female students, while dietary habits should be improved. However, one in eight dental students is at high caries risk. By assessing the level of caries experience, targeted strategies can be developed to promote, maintain, and enhance oral health among dental students.

Digital transformation in education and relevant calls for action are recognised global priorities aimed to support education and training in the digital age. The experiences from the emergency remote teaching during the COVID‐19 pandemic and recent research findings reveal relevant advantages, challenges, as well as different students and teaching staff perspectives which should be carefully considered and integrated into institutional strategies and policies to improve and enrich students’ learning experience. The present study aimed to explore health sciences students' perspectives on online teaching and learning (T&L) in four domains—Satisfaction, Motivation, Interaction and Challenges, and to identify the preferred T&L models or tools. A total of 1,041 responses were collected, including 476 dental medicine (45.7%), 399 pharmacy (38.3%), and 166 medical students (15.9%). Overall Satisfaction was quite high (4.0 ± 1.2; out of 5), followed by satisfactory Interaction (3.4 ± 1.4), whereas Motivation was quite low on average (3.0 ± 1.5). Challenges in online T&L were not markedly expressed (3.0 ± 1.6). The majority of students (46.6%) opted for the blended model as the preferred T&L model. Moodle lessons were perceived as the most useful online T&L tool (45.5% of students), followed by video materials (32.2%). Other T&L tools which require more active student's role, such as short test/quiz, and group or team assignment were declared as less favourable. The findings from the current study may contribute to raising the awareness of academic staff and higher institutions management about the student attitudes and needs related to online T&L and inform institutional planning, decision‐making and policy development.

Introduction/Objective. Artificial enamel caries lesions are commonly created to simulate in vivo caries development and to examine the effect of non-invasive and microinvasive approaches in treatment of initial caries lesions. The objective of the present study was to compare three different demineralizing solutions and exposing times in terms of the formation of artificial white spot lesions and to evaluate their demineralization effect through scanning electron microscopy observations. Methods. Twenty intact human premolars, extracted for orthodontic reasons, were thoroughly cleaned, stored in 0.1% thymol solution at room temperature and cut at the cementoenamel junction before demineralizing process. The specimens were randomly divided into three experimental groups, according to the used demineralization agent and the time of exposure: Group I (acetic acid; pH = 4.4; 96 hours); Group II (lactic acid; pH = 4.5; 120 hours); Group III (Lactic acid; pH = 4.3; 504 hours) and one control group (saline). After demineralisation, macroscopic appearance was checked and all specimens were observed under scanning electron microscope to evaluate the enamel characteristics and caries lesion depths. Results. In Group I and II enamel subsurface porosity with dissolution of enamel crystals is detected and the mean depths of white spot lesions were 48.55 ?m (SD = 1.11) and 43.23 ?m (SD = 6.74), respectively. In Group III structural integrity of enamel surface was not preserved. Conclusion. Demineralizing solutions used in experimental groups I and II resulted in artificial initial caries lesions with satisfactory characteristics and similar appearance on scanning electron microscopy. The outcome of demineralizing process which lasted 504 hours were cavitated enamel lesions.

Students are particularly vulnerable from the mental health aspect, which was especially recognized during the COVID-19 pandemic. This study aimed to reveal the impact of COVID-19 on quality of life (QoL) and mental health among dental students. The study was conducted on a sample of 797 students (207 male and 592 female) with an average age of 21.7 ± 2.4, from the School of Dental Medicine, University of Belgrade. The measurements used in the study were the Demographic and Academic Questionnaire, Questionnaire about exposure to COVID-19, COVID-19-Impact on QoL Questionnaire (COV19-QoL), Generalized Anxiety Disorder 7-item (GAD-7) scale, and Patient Health Questionnaire (PHQ-9). The mean total score for COV19-QoL was 2.9 ± 0.9, while the diagnostic criteria of GAD-7 and depression met 19.9% and 31.4% of students, respectively. There was a positive and strong correlation between QoL, anxiety, and depression. During COVID-19, predictors for lower perceptions of QoL were female gender and death of close relatives (p = 0.049, p = 0.005, respectively). At the same time, predictors for GAD were female gender, living in dormitories, and death of close relatives (p = 0.019, p = 0.011, p = 0.028, respectively), while for depression they were year of study, living with parents, and death of close relatives due to COVID-19 (p = 0.012, p = 0.008, p = 0.029, respectively). The study showed that students’ QoL and mental health during the pandemic were at high risk.

This study aimed to investigate the effect of 150 mg/L sodium fluoride (NaF) on redox status parameters and essential metals [copper (Cu), iron (Fe), and zinc (Zn)] in the blood, liver, kidney, brain, and spleen of Wistar rats and to determine the protective potential of selenium (Se) against fluoride (F ^- ) toxicity. Male Wistar rats were randomly distributed in groups of five (n=5) receiving tap water (control) or water with NaF 150 mg/L, NaF 150 mg/L + Se 1.5 mg/L, and Se 1.5 mg/L solutions ad libitum for 28 days. Fluorides caused an imbalance in the redox and biometal (Cu, Fe, and Zn) status, leading to high superoxide anion (O ^{2 .-} ) and malondialdehyde (MDA) levels in the blood and brain and a drop in superoxide dismutase (SOD1) activity in the liver and its increase in the brain and kidneys. Se given with NaF improved MDA, SOD1, and O ^{2 .-} in the blood, brain, and kidneys, while alone it decreased SH group levels in the liver and kidney. Biometals both reduced and increased F- toxicity. Further research is needed before Se should be considered as a promising strategy for mitigating F ^- toxicity.

Introduction. In children and growing adolescents, ankylotic resorption (i.e., progressive replacement resorption) of a permanent tooth is a serious complication. An ankylosed tooth root is continuously resorbed and replaced with bone; normal growth of alveolar bone is disturbed and infraposition of the dental crown progresses. This article aims to present decoronation as a very good treatment option for permanent incisors diagnosed with progressive replacement resorption in children and adolescents. Case outline. A 9.5-year-old boy was referred with non-vital both upper central permanent incisors due to dental trauma. In the left one, which had been re-implanted 90 minutes after avulsion, progression of clinical and radiographic pathological signs of ankylotic resorption was observed over the months. To prevent the local arrest of alveolar ridge growth and tilting of adjacent teeth, we decoronated the ankylosed tooth. For aesthetic and functional rehabilitation adhesive bonding of his dental crown was performed. Conclusion. In growing individuals with progressive replacement resorption, a dentist should be aware of decoronation as an effective treatment option with a predictable outcome.

Background/Aim: The aim of this study was to investigate: self-reported oral health, oral health related habits, nutrition and use of dental services among refugees and migrants in Serbia. Methods: Total of 226 migrants participated in the study. Participants were situated in the migrant centers Obrenovac and Krnjaca, in Belgrade, Serbia. All participants were given a questionnaire in order to examine oral health habits, attitudes and behavior among refugees and migrants. The questionnaire consists of 29 questions. SPSS 24 statistical software was used to analyze answers from the questionnaire. Results: Out of 226 examinees, 40 were female and 186 were male. Majority were adults (87.6%) and 12.4% were children. The results show that refugees and migrants who spend 200-300€ per month consume the most alcohol (33.3%) and tobacco (61.1%). Only 10.8% of men answered they have been to the dentist in Serbia, whereas 35% women had the same answer (p=0.000). The research also showed that most women (67.5%) brush their teeth 2-3 times a day and noticeably less men (37.1%) had the same habit. Fluoride supplements are used by 78.7% of examinees. Among most common reasons for the last visit to the dentist were pain (36.9%) and regular checkups (22.5%). Conclusion: Preservation of oral health of refugees and migrants in Serbia depends on various factors. Improving and preserving good general and oral health of refugees and migrants should be a public healthcare priority.