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Abstract Antiferromagnets have attracted significant attention in the field of magnonics, as promising candidates for ultralow-energy carriers for information transfer for future computing. The role of crystalline orientation distribution on magnon transport has received very little attention. In multiferroics such as BiFeO3 the coupling between antiferromagnetic and polar order imposes yet another boundary condition on spin transport. Thus, understanding the fundamentals of spin transport in such systems requires a single domain, a single crystal. We show that through Lanthanum (La) substitution, a single ferroelectric domain can be engineered with a stable, single-variant spin cycloid, controllable by an electric field. The spin transport in such a single domain displays a strong anisotropy, arising from the underlying spin cycloid lattice. Our work shows a pathway to understanding the fundamental origins of magnon transport in such a single domain multiferroic.

Background: This study aims to compare the efficacy between conventional exfoliative cytology (EC) and centrifuged liquid-based cytology (CLBC) in control, leukoplakia, and oral squamous cell carcinoma (OSCC) patients. Oral leukoplakia and oral cancer require an early definitive diagnosis for better prognostic outcome. Oral EC, a minimally invasive technique that involves the examination of desquamated cells from the tissue surfaces used as a method of early diagnosis. CLBC is a modified technique that is used to achieve improved quality of the cytology findings. Materials and Methods: A comparative study was done in 30 subjects, of which, 10 cases from control group, 10 oral leukoplakia, and 10 OSCC cases. These subjects were selected according to the appropriate inclusion and exclusion criteria. The cases in each group underwent conventional as well as CLBC. The comparison was carried out between these groups with respect to the cellular and background stromal factors. Appropriate qualitative evaluation of the samples was collected and statistical analysis was done using the Chi-squared test. The significance level of value was P < 0.05. Results: Significant results were obtained for certain parameters such as cellular overlap clear background, uniform distribution in control, leukoplakia, and OSCC with a P = 0.004**, P = 0.001**, P = 0.006** using CLBC. Conclusion: CLBC is better and give clearer vision as compared to conventional cytology and can be used in the early diagnosis.

Background: The present study was conducted to assess the relationship between drinking water fluoride (F) levels, dental fluorosis dental caries, and associated risk factors in the elderly population. Materials and Methods: A cross-sectional analytical study was conducted on 50 patients aged 25–60 years, selected by stratified random sampling from different areas with different levels of naturally occurring F in drinking water. The patients were assessed for dental fluorosis according to WHO basic survey guidelines. The overall oral health status of the patients was assessed by decayed missing filled teeth DMFT index and the bacterial count of saliva was calculated using the Caries Risk Test (CRT). Statistical analysis was done using mean, standard deviation, standard error, Z-test, Mann-Whitney U Test, and Chi-square test. Results: The results of the present study revealed that the prevalence of fluorosis was 24%. The number of patients with dental fluorosis was highest in those who consumed water with high groundwater fluoride levels irrespective of the source of drinking water. Caries prevalence in the study population was about 5.56 ± 1.95. Conclusion: There was a moderate prevalence of fluorosis in patients, and caries prevalence is high in areas below optimal F areas. Caries prevalence and mean DMFT scores were least common in patients with optimal fluoride levels in drinking water and highest in those with below optimal fluoride in drinking water.

Background: In recent days, tissue eosinophils are considered to have more impetus role in the biological behavior of various tumors. Compared to routine hematoxylin and eosin stain, the special stains such as carbol chromotrope for eosinophils are considered to be more specific and definitive for its evaluation in routine histopathology. Aim: This study aims to evaluate and compare the infiltration of tissue eosinophils in different grades of oral squamous cell carcinoma (OSCC) using a special stain – carbol chromotrope and to investigate the prognostic role of tissue eosinophils in OSCC. Methodology: The study was carried out with the sample size of fifty histopathologically diagnosed cases of OSCC, of which twenty cases were well differentiated, twenty cases were moderately differentiated, and ten cases were poorly differentiated, and comparison of infiltration of tissue eosinophils in the different grades of OSCC was done using special stain. The tissue sections were stained with carbol chromotrope special stain. Results: In the present study, more number of tissue eosinophils were seen in well-differentiated OSCC cases than the moderately and poorly differentiated OSCC cases, and the analysis of variance test showed P < 0.001. Tukey B's post hoc range test showed that mean scores fell in three different subsets, and the least mean score was observed in the poorly differentiated group (2.20) and the highest mean score was observed in the well-differentiated group (34.75). Conclusion: The results proved that the presence of more number of tissue eosinophils in well-differentiated OSCC is associated with favorable prognosis and that quantitative assessment of tissue eosinophilia should become a part of the routine histopathological diagnosis for the different grades of OSCC.

BiFeO3 has a wide application but the impact of rare-earth substitution for the evolution of the coupling mechanism is unknown. Here, the authors reveal the correlation between ferroelectricity, antiferromagnetism, a weak ferromagnetic moment, and their switching pathways in La-substituted BiFeO3.

Context: Problem-based learning (PBL) is mostly a student-centered learning method, and it is a new method used in medical and dental education all over the world. In India, PBL is a part of the learning process sparingly followed. Contrary to other institutions, PBL has been introduced in dental curriculum along with the traditional curriculum very recently. Aim: The aim of this study was to evaluate the newly introduced PBL curriculum among the dental students using a closed-ended questionnaire on a five-point scale. Materials and Methods: The questionnaire on PBL was prepared in Google Forms, comprising 22 closed-ended questions on a five-point Likert scale, ranging from strongly disagree (1) to strongly agree (5). We carried out a pilot study in 10% of the target population to check validity and feasibility. Final study was conducted in the targeted population of 185 dental students who had undergone PBL sessions. Results: The responses for the questionnaire thus received from the students were compiled and analyzed using Google Forms software. Overall rating of PBL by the respondents was as follows. The majority of the student’s responses were agreed with 54.6% and a significant number of students strongly agreed with PBL at 33%. Conclusions: This study shows the responses of the students on aspects of group learning, imparting content knowledge, improvement of group skills, improvement of communication skills, and carrying out self-directed learning within the Indian context of dental health education.

Introduction: Odontogenic keratocysts, dentigerous cysts, and ameloblastoma are the most common forms of cystic pathology that affect the jaw bones. The purpose of this study was to assess the immunohistochemical expression of laminin 1 in these lesions and to study the probable role of laminin 1 in their biologic behavior. Materials and Methods: Serial sections of 4 µm were obtained from the archival blocks using standard microtome. One set of sections was used for immunohistochemical study. Presence of brown colored end product at the site of target antigen was considered as positive immunoreactivity. Results: Of the 10 ameloblastomas, 9 were positive. Among the 10 odontogenic keratocysts, 9 showed a positive immunoreactivity for laminin 1 and 1 case was negative. Among the 10 dentigerous cysts, all of them showed a positive immunoreactivity for laminin 1. A statistical analysis was carried out using chi-square test and the statistical significance was evaluated. Discussion: All the lesions that showed positive immunoreactions for laminin 1 had basement membrane immunolocalization. The laminin 1 in odontogenic keratocysts showed that it is not involved in the formation of daughter cysts and the separation of epithelium and surrounding connective tissue. Conclusion: Expression of laminin 1 in the stellate reticulum can be a sign of the aggressiveness of ameloblastoma. Laminin 1 expression in the lining epithelium of dentigerous cyst can be used to explain its potential to transform to ameloblastoma. It can be concluded that the nature and aggressiveness of odontogenic cysts and tumors can be explained using laminin 1.

Context: Dental offices are known to be one of the largest users of inorganic mercury in the preparation of amalgam-a restorative material which, if not handled and disposed through scientific methods, can pose grave threats to the biosphere. Aims: The objective of this study was to assess and record the mercury management and disposal strategies of dental practitioners belonging to the two South Indian states, Kerala and Tamil Nadu. Subjects and Methods: A questionnaire regarding the usage and disposal of a filling material containing mercury (amalgam) was designed and distributed online. The 150 dental practitioners partaking in this study responded anonymously. Results: The results were statistically analyzed using chi-square test and the P value was evaluated. The usage of amalgam was correlated with the age of the practitioner and the nature of practice and it was found to be statistically significant. The number of fillings was correlated with the years of practice and locality of the clinic, which were found to be statistically significant. Conclusions: This study showed that mercury was widely preferred and utilized even today as a restorative material by dentists and dental specialists, despite the availability of other alternative strategies. Only a minor section of practitioners were found to be aware of the global changes in the guidelines pertaining to the handling and disposal of amalgam. We feel that Safe Mercury Amalgam Removal Technique, amalgam safety rules, and amalgam-free practice should be a part of the academic curriculum and continuing dental education.

Introduction: Medical as well as dental professionals are always at an increased risk of contracting infections in pandemics. The novel Coronavirus (nCoV), the causative agent of the COVID-19 pandemic is more contagious than other known members of Coronaviridae family. Aim: This research aims to evaluate the knowledge, psychological, social, and economic aspects of COVID-19 pandemic among dental professionals using a closed-ended questionnaire study. Materials and Methods: A cross-sectional study with close ended questionnaire was planned. The questionnaire form was prepared in the Google platform after receiving ethical clearance, with 39 questions under the headings of General Information, Knowledge, Psychological aspects, and Social and Economic aspects. The questionnaire link was circulated among dental professionals known to the research team through Email, WhatsApp, and Messenger. A total of 504 dental professionals participated in this study in five days. Knowledge score was calculated, and psychological stress was calculated using Likert scale. Economic aspect was measured using yes/no answers. Data were entered in an excel sheet and the data obtained were statistically analysed using the SPSS software, version 11.5. Chi-square test was done to evaluate whether there is an association between knowledge score and demographic factors and p-value was obtained. Results: There was almost equal gender distribution of respondents in the study. p-value obtained from chi-square test results correlating knowledge score with various demographic factors was not significant. A 59.9% of study participants were poorly informed on methods used to diagnose COVID19 infection. A 44.4% of the respondents were psychologically stressed about infecting their family members and 72.22% were economically affected because of their profession. A 98.61% of the participants reported that they will wash their hands frequently, avoid crowded places and cancel travel plans in the near future. Conclusion: The present study evaluated the knowledge, psychological, social and economic aspects of COVID-19 pandemic among dental professionals. We identified that there is an urgent need to intensify the knowledge on COVID-19 and also to give psychological, social and economic support to dental professionals.

Introduction: Molar Incisor Hypomineralisation (MIH) is a qualitative defect of enamel which is more prone to posteruptive enamel breakdown resulting in the early invasion of dental caries compared to a normal enamel tooth structure. Aim: To assess the differences in the enamel permeability of permanent teeth with and without MIH using Scanning Electron Microscopy. Materials and Methods: Out of the sixteen children, eight children with and eight without MIH were randomly selected. Fully erupted maxillary anterior teeth were subjected for evaluation in this study. Vinyl Polysiloxane impression material was used to make impressions for SEM evaluation. The teeth surfaces were divided, into 9 different morphological areas for assessment. Negative replicas representing enamel droplets were assessed. Odd’s ratio was calculated by Logistic Regression Analysis. Results: Presence of enamel droplets was noticed in both the groups, more predominantly in teeth with MIH. On comparing the individual regions, presence of enamel droplets in the hypomineralised areas had significant difference compared to normal enamel, with p-value 0.0012, which was statistically significant, with an odds ratio of 3.4. Conclusion: This study demonstrated a high presence of droplets in MIH teeth compared to teeth without MIH, suggesting a possible high enamel permeability which in turn can be a predisposing factor for dental caries in teeth with MIH.

Background: High levels of fluoride in the drinking water, especially ground water, results in skeletal fluorosis which involves the bone and major joints. This study was conducted to assess the prevalence of skeletal fluorosis to compare with dental fluorosis in an endemically fluorosed population in the District of Salem, Tamil Nadu. Materials and Methods: Institutional ethical clearance was obtained. A total of 206 patients who reported to the Department of Hematology for blood investigations were the participants in this study. Age, sex, place, weight, height, dental fluorosis, and skeletal complaints were noted down. Body mass index was calculated, and statistical analysis was performed. Results: Dental fluorosis was present in 63.1% and absent in 36.9% of the samples reported. Skeletal fluorosis was present in 24.8% and was absent in 75.2%. A large number of the patients had knee pain and difficulty in bending. Chi-square test was used for statistical analysis. Skeletal fluorosis and age were compared and P value was 0.00 and was significant. Dental fluorosis and skeletal fluorosis were compared and P value was found to be 0.000 and significant. Discussion and Conclusion: There is a need to take measures to prevent dental and skeletal fluorosis among the residents of Salem district. Calcium balance should be maintained, and fluoride intake should be minimized to reduce the symptoms. The government should provide water with low fluoride level for drinking and cooking. Once the symptoms develop, treatment largely remains symptomatic, using analgesics and physiotherapy.

Context: There are various regions in India that have high levels of fluoride in drinking water sources. Many people residing in such places suffer from dental fluorosis (DF). Aims: To evaluate the prevalence of DF in children residing in Salem and also to find any correlation between DF and other related factors. Materials and Methods: One school from each block of Salem (total 21 blocks) was selected for the study. A single examiner had evaluated untreated caries, lesions, and DF (for permanent anterior teeth and molars) using the Dean's fluorosis index, in all children. Water fluoride level determination at each school was done using the Tamil Nadu Water Fluoridation and Drainage Board field kit. Other factors that may have contributed to DF were assessed using a questionnaire, which was provided to each student. The data obtained were statistically analyzed using the SPSS software version 11.5. Statistical Analysis: Chi-square test was used for statistical analysis. Results: DF was present in 56.9% of the children examined. It was mostly seen in 9 years old (72%) and male (59%) children. A positive correlation was found between the occurrence of DF and the duration of residence in a place with high water fluoride content, consumption of borewell water (64%), the parts per million of fluoride in drinking water, consumption of black tea (59%). However, no correlation was found between DF, dental caries, consumption of milk, or consumption of foods cooked in aluminum vessels. Conclusion: There was a correlation between DF and factors such as male gender, bore well water consumption, black tea consumption and the duration of residence in a place with high water fluoride content.

Mutual trust and relationship between doctors and patients is an important factor of treatment plan. Changing trends in medical field does affect this relationship. This article reviews the basic code of conduct for every medical practitioner.

Context: Inducible nitric oxide synthase (iNOS) is a cytoplasmic enzyme which plays a crucial role in the pathogenesis of oral carcinomas and sarcomas. Aims: The objective of this study was to analyze the immunohistochemical expression of iNOS in carcinomas and sarcomas affecting the oral cavity in order to understand the possible role of iNOS in their biologic behavior and to correlate iNOS expression with lymph node metastasis in carcinomas and sarcomas. Settings and Design: Patients, who attended the oral diagnosis department of Vinayaka Missions Sankarachariyar Dental College, were screened, for the purpose of the study. Besides these, paraffin-embedded tissue blocks were also retrieved from archives of the Oral and Maxillofacial Pathology Department. A total of 40 cases (20 carcinomas and 20 sarcomas) were selected for the study. Subjects and Methods: A total of 40 cases (20 carcinomas and 20 sarcomas) were selected for the study. Five apparently normal tissues were obtained from the tumor adjacent normal tissue to be used as a control. These were subjected to immunohistochemical staining using antibody to iNOS and evaluated. Statistical Analysis Used: The results were analyzed using the Chi-square test. Results: Among the 20 carcinomas 19 showed a positive immunoreactivity for iNOS and 1 case was negative. Among the 19 immunopositive iNOS cases of carcinomas, 15 cases showed positive lymph node metastasis. Among the sarcomas, positive immunoreactivity for iNOS was seen in 10 hard tissue sarcomas, while the remaining 10 soft tissue sarcomas were negative for iNOS expression. The results were analyzed using the Chi-square test. Conclusions: iNOS is a reliable marker for lymph node metastasis in carcinomas irrespective of the histologic grade. The high expression in carcinomas shows that the carcinomas elaborate more angiogenesis for growth compared with the sarcomas with the exception of hard tissue sarcomas.

Introduction: In multiple-appointment root canal treatment, a temporary filling material is used to seal the access cavity between visits. The primary function of this material is to prevent the contamination of the root canal system by fluids, organic debris, and bacteria from the oral cavity. Material and Methods: A total of fifty extracted noncarious unrestored human maxillaryanterior teeth with intact crowns and roots were selected The canals were instrumented using stepback technique and sodium hypochlorite (3%) and hydrogen peroxide (3%) were used as irrigants for each specimen alternatively. The coronal two-thirds of each canal were flared using Gates-Glidden drills up to no. 3 size and obturated with Gutta-percha using zinc oxide-eugenol (ZnOE) as sealer. The teeth were then randomly selected and divided into six groups out of which four were experimental groups and two control groups. The teeth were then immersed in 2% methylene blue dye solution for 3 days. All sealing materials and Gutta-percha were gently removed from the walls of the canal, and the entire circumference of the canal wall examined for dye penetration. Results: The lowest mean leakage was in the Fermit-N group followed by Cavit-W, ZnOE, intermediate restorative materials (IRM), and positive control. Conclusion: Fermit-N showed better sealing ability compared to cavit, ZnOE and IRM.

Increased intake of fluoride in water and diet results in dental and skeletal fluorosis. Many states in India are affected by fluorosis. The optimum level of fluoride in drinking water for anti-cariogenic effect was thought to be 1 ppm. Various effects of fluoride on plants, animals and humans are discussed here. Currently, it is identified that fluoride has significant role in gene polymorphisms and lowered intelligent quotient.

Over the past two decades, there is an increasing number of congenital defects affecting enamel mineralisation referred to as "molar incisor hypomineralisation" (MIH). This defect usually involves one to four permanent first molars and permanent incisors. Clinically, the defect presents as opaque lesions varying in colour from white to yellow or brown, with a sharp demarcation between the affected and sound enamel to posteruptive enamel breakdown. The destruction of enamel is so rapid and clinically, it presents as if the enamel has not formed at all. It has been postulated that MIH is a consequence of a variety of environmental factors acting systemically, which disturb the ameloblasts during amelogenesis. However, the possibility of a genetic component in the development of MIH cannot be excluded. Management of MIH always pose a big problem to the clinicians, as well as for the child due to severe sensitivity caused by the defective enamel.

Background: Tamil Nadu is one of the 18 states affected by fluorosis in India. The maximum tolerance limit of fluoride in drinking water specified by the World Health Organization (WHO, 1984) is 1.5 mg/l while it is proved to be above in many areas of Salem. Aims and Objectives: The aim of the following study is to identify the prevalence of dental fluorosis among children in the district of Salem. To compare the prevalence of dental fluorosis between different sexes and age groups. Materials and Methods: A pilot study was conducted in a private school where oral examination was done using mouth mirror and probe under sunlight in 965 students, for the presence or absence of dental fluorosis. As it was a pilot study, the fluorosis indexes were not taken into consideration. Results: In our study, 965 students were examined for dental fluorosis out of which, 624 were boys and 341 were girls. Dental fluorosis was present in 31.1% of boys, and 30.3% of girls 297 students out of 965 (30.8%) showed the presence of dental fluorosis. Conclusion: The present study showed that Salem is one of the districts affected by dental fluorosis in Tamil Nadu. An extensive study including the grades of fluorosis and estimation of water fluoride levels in different areas is required for better evaluation of the situation. Government should take actions to prevent fluorosis. Awareness should be given to the population to drink only the water supplied by the government.

Introduction: Dental caries is a disease with multifactorial etiology. Early detection and preventive measures are essential for caries control. Caries activity tests are one of the methods of early detection, but all these are based on microbiological study. Aims: Compare the sensitivity and specificity of Snyder test (ST), lactobacillus count (LBC) and Cariostat in mixed dentition children with and without caries. Materials and Methods: 90 healthy mixed dentition children (79 boys and 11 girls) were selected and were divided into two groups, one with Decayed missing filled teeth (DMFT) 0 and another group with DMFT 3-5. The salivary samples were collected for ST and LBC and plaque samples were collected for Cariostat. Caries activity was assessed. Results: The data obtained were analyzed for sensitivity, specificity, positive predictive value, negative predictive value and over all accuracy. Conclusions: Our present study showed that the LBC was found to have a higher correlation in caries as the caries increased the count also increased with positive caries activity. A good correlation was found between Snyder and LBC for the caries activity 1, 2 and 3. But no correlation was seen for score 0. To conclude, a combination of all these tests was found to be good for assessing caries risk groups.

Aim: The aim of the study was to evaluate the pediatric oral biopsies received between 2002-2011 from a dental and maxillofacial centre in Salem, Tamilnadu, India retrospectively based on age, sex, site and type of the pathologies. Materials and Methods: The records of dental and maxillofacial surgery centre were taken and a retrospective evaluation of the pediatric lesions biopsied over a period of ten years (2002-2011) was done. Patients aged 15 years and below were considered as pediatric patients and pathologies were grouped into 8 categories, according to age, gender, anatomic location and pathologic diagnosis. Results: A total of nine hundred twenty five biopsies were studied, of which 97 cases were from pediatric patients. The pathologies were predominant in mandible to maxilla (47:29). The distribution of the pathologies were 44 odontogenic pathologies, 18 connective tissue tumours, 3 salivary gland tumours, 5 fibro osseous lesions and 25 tumour like lesions. Out of this 44 odontogenic pathologies, 39 were odontogenic cysts, and 5 were odontogenic tumours. Conclusion: Unlike other studies, the lesions were more common in the mandible with a female predilection. The majority of oral and maxillofacial lesions detected in pediatric population were benign similar to the previous reports.

Introduction: Cancer has multifactorial aetiology and is a multistep process involving initiation, promotion and tumour progression. Cellular proliferation is one of the important indicators for the biologic aggressiveness of a malignant lesion. The dysregulated proliferation may be a significant change to determine the potential prognosis of various malignant tumours. Aim: The aim of this study was to evaluate the expression of proliferating cell nuclear antigen (PCNA) as an indicator for clinical aggressiveness in oral premalignancy and squamous cell carcinoma. Materials and Methods: A total of 50 blocks were taken from the Department of Oral Pathology which was diagnosed previously histopathologically. It comprised of normal oral mucosa (10), dysplasia (10) and grades of oral squamous cell carcinoma (30) of patients between the age group of 40–60 years. From each block, sections of 4 micro metre thicknesses were prepared and placed on poly- L lysine coated slides. These sections were immunohistochemically stained with monoclonal proliferating cell antibody (PC10). The stained slides were evaluated by a single examiner for cell count. Results: A comparison between study groups and controls showed a probability value (p-value) < 0.05. Significant increase in the proliferative index from the normal to oral squamous cell carcinoma was noticed. Poorly differentiated squamous cell carcinoma showed maximum proliferative index followed by moderately differentiated, well differentiated squamous cell carcinoma, dysplasia and normal mucosa. Conclusion: Present study concluded that PCNA index can be used to assess the proliferation and aggressiveness in dysplasia and different grades oral squamous cell carcinoma.

Introduction: Supernumerary teeth refers to an excessive number of teeth and are relatively common in the oral cavity. The supernumerary tooth located in the midline of the maxilla between the central incisors is referred to as "mesiodens." The present study emphasizes the importance of multidisciplinary management and long-term follow-up of patients with mesiodens. Aim of the Study: This study investigates the characteristics of mesiodens among children in patients reported to department of pediatric and preventive dentistry in an institution in the state of Tamil Nadu, India. Materials and Methods: The study population consisted of 55 children below 14 years. The characteristics of mesiodens were obtained from radiographs and clinical examination. And all these were confirmed as mesiodens by surgical intervention. Results: Results showed that males were affected approximately 2 times as frequently as females. Predominant shape of the mesiodens was conical (79.7%). 27 (49.09%) of 55 patients had multiple mesiodens. 25 (45.45%) of 55 patients required orthodontic correction after surgery. Conclusions: Mesiodens can cause many complications. So routine radiographic examination of all pediatric patients is advised. And when identified, they should be extracted as early as possible in children and adolescents in order to avoid possible complications.