A comparative evaluation of masticatory load distribution in different types of prosthesis with varying number of implants: A FEM analysis.

Aim: To identify the optimal number and position of implants to reduce stress concentration on the implant, denture, and attachment system for sustaining an overdenture prosthesis. Materials and methods: By incorporating one to eight indigenous implants with bar-type attachments, eight 3D finite element models of mandibular overdentures were created. All models received a 200 N vertical load, and the biomechanical characteristics of peri-implant bone were assessed. Result: The study observed that with a vertical load of 200 N, the maximum equivalent stress around peri-implant tissue in all models was within the physiological tolerance threshold of bone. The von Mises stress values ranged from 116.18 MPa to 536.7 MPa. Conclusion: The three-implant-supported overdenture model revealed superior peri-implant stress, stability, cost-effectiveness, and hygiene maintenance outcomes. Placing a third implant in the mid-symphysis region may offer a practical solution to reduce rotations in two-implant-supported overdentures.

Peri-implant stress distribution assessment of various attachment systems for implant supported overdenture prosthesis by finite element analysis - A systematic review.

Background: Various attachments like ball, bar-clip, magnetic attachments are used in implant supported overdentures. Finite Element Analysis (FEA) a newly innovated technology has been used in dental implantology to evaluate stress distribution patterns. There is little evidence available regarding the stress distribution in peri-implant region for implant supported overdentures. The purpose of the review was to generate scientific evidence on peri-implant stress distribution in FEA model with different types of attachments employed in implant supported overdentures. Materials and methods: Systematic review was conducted as per the Preferred Reporting Items for Systematic Reviews Guidelines and Meta-Analyses statement (PRISMA). A comprehensive search was undertaken by two reviewers from January 2020 to June 2020 with no year limits to published articles. Only in-vitro FEA studies were included. Following electronic databases were searched for published studies- PubMed, Web of Science. Characteristics of the studies tabulated and analysis of articles was done to compare different attachment systems. Results: Locator attachments showed better stress distribution than ball attachment system in all the studies but one. Two studies showed results in favour of ball attachment compared to bar-clip attachment system when stress was evaluated distal to the implants. No significant difference in terms of stress concentration could be generated between ball versus magnetic/equator versus locator attachment system due to less number of studies and conflicting results. Conclusion: Various studies showed different results due to heterogenicity in selected attachment systems and study designs. Locator attachments showed favourable stress distribution around peri-implant bone than other attachments.

Identification and phylogenetic characterization of bovine ephemeral fever virus (BEFV) of Middle Eastern lineage associated with 2018-2019 outbreaks in India.

Bovine ephemeral fever virus (BEFV) is an evolving arbovirus reported across tropical, subtropical and temperate climatic zones globally. This study reveals prominent BEFV outbreaks in India, emerging annually during monsoons in subtropical areas accompanied by a congenial abundance of the vector population. PCR-based detection of viral genomic RNA in the blood samples collected during outbreaks of 2018-2019 for the first time confirmed the presence of BEFV in India. Phylogenetic analysis based on the glycoprotein gene of BEFV showed the current isolates to have high sequence homology with Middle Eastern lineage with nearly 97%, identity to Turkey (BEFV Ad12/TUR) and Israel (Israel 2006) isolates.

Genetic Association of ACE2 rs2285666 Polymorphism With COVID-19 Spatial Distribution in India.

Studies on host-pathogen interaction have identified human ACE2 as a host cell receptor responsible for mediating infection by coronavirus (COVID-19). Subsequent studies have shown striking difference of allele frequency among Europeans and Asians for a polymorphism rs2285666, present in ACE2. It has been revealed that the alternate allele (TT-plus strand or AA-minus strand) of rs2285666 elevate the expression level of this gene upto 50%, hence may play a significant role in SARS-CoV-2 susceptibility. Therefore, we have first looked the phylogenetic structure of rs2285666 derived haplotypes in worldwide populations and compared the spatial frequency of this particular allele with respect to the COVID-19 infection as well as case-fatality rate in India. For the first time, we ascertained a significant positive correlation for alternate allele (T or A) of rs2285666, with the lower infection as well as case-fatality rate among Indian populations. We trust that this information will be useful to understand the role of ACE2 in COVID-19 susceptibility.

The peopling of Lakshadweep Archipelago.

The archipelago of Lakshadweep is considered as a stopover to the maritime route since ancient time. It is not very clear when the human first occupied these islands, however in the long history of the islands, the local legends suggest that Lakshadweep has been ruled by different kingdoms. To have a better understanding of peopling of Lakshadweep, we have analysed 557 individuals from eight major islands for mitochondrial DNA and 166 individuals for Y chromosome markers. We found a strong founder effect for both paternal and maternal lineages. Moreover, we report a close genetic link of Lakshadweep islanders with the Maldives, Sri Lanka and India. Most of the Lakshadweep islands share the haplogroups specific to South Asia and West Eurasia, except Minicoy Island that also shares haplogroups of East Eurasia. The paternal and maternal ancestries of the majority of island populations suggest their arrival from distinct sources. We found that the maternal ancestry was closer to South Indian populations, whereas the paternal ancestry was overwhelmed with the haplogroups, more common in the Maldives and North of India. In conclusion, our first genetic data suggest that the majority of human ancestry in Lakshadweep is largely derived from South Asia with minor influences from East and West Eurasia.

Unravelling the distinct strains of Tharu ancestry.

The northern region of the Indian subcontinent is a vast landscape interlaced by diverse ecologies, for example, the Gangetic Plain and the Himalayas. A great number of ethnic groups are found there, displaying a multitude of languages and cultures. The Tharu is one of the largest and most linguistically diverse of such groups, scattered across the Tarai region of Nepal and bordering Indian states. Their origins are uncertain. Hypotheses have been advanced postulating shared ancestry with Austroasiatic, or Tibeto-Burman-speaking populations as well as aboriginal roots in the Tarai. Several Tharu groups speak a variety of Indo-Aryan languages, but have traditionally been described by ethnographers as representing East Asian phenotype. Their ancestry and intra-population diversity has previously been tested only for haploid (mitochondrial DNA and Y-chromosome) markers in a small portion of the population. This study presents the first systematic genetic survey of the Tharu from both Nepal and two Indian states of Uttarakhand and Uttar Pradesh, using genome-wide SNPs and haploid markers. We show that the Tharu have dual genetic ancestry as up to one-half of their gene pool is of East Asian origin. Within the South Asian proportion of the Tharu genetic ancestry, we see vestiges of their common origin in the north of the South Asian Subcontinent manifested by mitochondrial DNA haplogroup M43.