Browsing by Author "Rajesh Bansal"

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A comparative evaluation of masticatory load distribution in different types of prosthesis with varying number of implants: A FEM analysis
(Elsevier B.V., 2024) Roopal Srivastava; Rajesh Bansal; Pavan Kumar Dubey; Deepak Singh
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. © 2024
A novel G to A transition at initiation codon and exon-intron boundary of PAX9 identified in association with familial isolated oligodontia
(Elsevier B.V., 2017) Tanmoy Sarkar; Rajesh Bansal; Parimal Das
Several studies on experimental animals indicate that the process of organogenesis crucially depends upon the spatiotemporal dose of certain critical bio-molecules. Tooth development is also not an exception. While most of the knowledge regarding the molecular mechanism of tooth development comes from the studies on mouse model, pathogenic variations identified in human tooth agenesis also provide valuable information on mammalian tooth development. Until now five major candidate genes have been identified for tooth agenesis in human. Among them, PAX9 plays the crucial role in tooth development and in non-syndromic congenital tooth agenesis. In this study, microsatellite and SNP based genotyping identifies a disease specific haplotype block, which includes PAX9 gene, segregates with autosomal dominant tooth agenesis phenotype. Direct sequencing of PAX9 identifies a novel heterozygous G to A transition at the third base (c.3G > A) of initiation codon leading to ATG to ATA shift in all affected individuals which is absent in all unaffected relatives and 200 control chromosomes. Further, in vitro functional analysis creating PAX9 minigene construct did apparently show no effect on the splice-site migration. It is therefore proposed that haploinsufficiency of PAX9 is the causal factor for tooth agenesis in this family. © 2017 Elsevier B.V.
Enhanced osteoblast proliferation and corrosion resistance of commercially pure titanium through surface nanostructuring by ultrasonic shot peening and stress relieving
(Allen Press Inc., 2014) Shitu Jindal; Rajesh Bansal; Bijay P. Singh; Rajiv Pandey; T. S. N. Shankar Narayanan; Mohan R. Wani; Vakil Singh
This investigation was carried out to study the effect of a novel process of surface modification, surface nanostructuring by ultrasonic shot peening, on osteoblast proliferation and corrosion behavior of commercially pure titanium (c p-Ti) in simulated body fluid. A mechanically polished disc of c p-Ti was subjected to ultrasonic shot peening with stainless steel balls to create nanostructure at the surface. A nanostructure (<20 nm) with inhomogeneous distribution was revealed by atomic force and scanning electron microscopy. There was an increase of approximately 10% in cell proliferation, but there was drastic fall in corrosion resistance. Corrosion rate was increased by 327% in the shot peened condition. In order to examine the role of residual stresses associated with the shot peened surface on these aspects, a part of the shot peened specimen was annealed at 400°C for 1 hour. A marked influence of annealing treatment was observed on surface structure, cell proliferation, and corrosion resistance. Surface nanostructure was much more prominent, with increased number density and sharper grain boundaries; cell proliferation was enhanced to approximately 50% and corrosion rate was reduced by 86.2% and 41% as compared with that of the shot peened and the as received conditions, respectively. The highly significant improvement in cell proliferation, resulting from annealing of the shot peened specimen, was attributed to increased volume fraction of stabilized nanostructure, stress recovery, and crystallization of the oxide film. Increase in corrosion resistance from annealing of shot peened material was related to more effective passivation. Thus, the surface of c p-Ti, modified by this novel process, possessed a unique quality of enhancing cell proliferation as well as the corrosion resistance and could be highly effective in reducing treatment time of patients adopting dental and orthopedic implants of titanium and its alloys.
Fabrication of orbital prosthesis by two different methods in patients with post-COVID-19 rhino-orbital maxillary mucormycosis: A case series
(Wolters Kluwer Medknow Publications, 2024) Bappaditya Bhattacharjee; Roopal Srivastava; Rajesh Bansal; Naresh K. Sharma
ABSTRACT: Neoplasms, congenital disorders, fungal infections, and traumatic injuries are the predominant causes of orbital defects. Various retentive mechanisms such as application of adhesive, utilization of mechanical undercuts, and implant-supported attachments are generally used in the maxillofacial prosthesis. In the orbital region, the result of magnet-retained attachments is favorable compared with other mechanisms. Different advantages of the magnet-retained prosthesis are less manual dexterity needed during insertion or removal and better maintenance of hygiene. The skin-implant interface and thick tissues in the maxillofacial region are the critically important points that should be given importance during the planning and placement of implants. Ideally, implant sites for orbital prosthesis are the lateral, infra-, and supraorbital rims of the orbital region. The following case series describes two different methods to rehabilitate patients with an exenterated eye due to mucormycosis by individually designed implant with magnetic attachment and mechanical undercut-retained orbital prosthesis. © 2024 Wolters Kluwer Medknow Publications. All rights reserved.
FAILURE ANALYSIS OF FRACTURED DENTAL IMPLANTS
(Association of Metallurgical Engineers of Serbia, 2022) Rajesh Bansal; Amit Raj Sharma; Vakil Singh
The success and predictability of titanium implants over long periods of time are well established, and there has been a tremendous increase in implant popularity among patients and clinicians over the last four decades. However, complications can occur, resulting in the loss of both the implant and the prosthesis. Dental implant fracture is uncommon; however, implants or abutment screws can fracture and cause significant problems for both the clinician and the patient. Improper design, overload, fatigue, and corrosion are all potential causes of implant fracture. Six retrieved fractured dental implants of varying diameter and thread design were collected on a regular basis to characterize their fracture behavior by SEM and assess the fracture mechanism. The majority of the implants were fractured as a result of fatigue crack initiation and propagation from the thread roots. © 2022, Association of Metallurgical Engineers of Serbia. All rights reserved.
Implant placement in the atrophic mandibular posterior region using the inferior alveolar nerve bypass technique after assessing the bone relative to the mandibular canal: A prospective interventional pilot study
(Wolters Kluwer Medknow Publications, 2025) Vandita Srivastava; Rajesh Bansal; Kausik Chattopadhyay; Monika Bansal
Introduction: Rehabilitation of the atrophic posterior mandible is very challenging because the distance between the crest of the ridge and the inferior alveolar canal (IAC) is very less. Inferior alveolar nerve bypass is a technique in which implants are placed bypassing the nerve, lingually or buccally. The objectives are to assess the bone around the mandibular canal on buccal and lingual sides and place implants in the posterior region of the atrophic mandible using the inferior alveolar nerve bypass technique. Materials and Methods:The bone with respect to IAC in 60 sites from 10 patients was assessed on both sides of the atrophic mandible.Measurements were taken at 10 mm, 20 mm, and 30 mm from the mesial aspect of the retromolar pad. After assessment, 20 implants were placed bypassing IAC in five patients, and postoperatively, neurosensitivity test was performed. Descriptive analysis was used to compare the different measurements from the retromolar pad on the right and left sides. Unpaired ‘t’ test was used. A P value less than 0.05 was considered as statistically significant. Results: The distance of the bone relative to IAC was statistically insignificant on right and left sides. Neurosensitivity test was negative on the first postoperative day. However, after the first and third months, there was positive response on the right side in 80% subjects and 100% on the left side. Conclusions: Dental implants were placed successfully in the atrophic mandible, bypassing the IAC. IAC is placed more lingually toward the medial border of the retromolar pad and then becomes buccally in the premolar region. Buccal bypass is safer and easier than lingual bypass due to the lingual position of IAC. © 2025 National Journal of Maxillofacial Surgery.
Optimization of Oxidation Temperature for Commercially Pure Titanium to Achieve Improved Corrosion Resistance
(Springer New York LLC, 2017) Rajesh Bansal; J.K. Singh; Vakil Singh; D.D.N. Singh; Parimal Das
Thermal oxidation of commercially pure titanium (cp-Ti) was carried out at different temperatures, ranging from 200 to 900 °C to achieve optimum corrosion resistance of the thermally treated surface in simulated body fluid. Scanning electron microscopy, x-ray diffraction, Raman spectroscopy and electrochemical impedance spectroscopy techniques were used to characterize the oxides and assess their protective properties exposed in the test electrolyte. Maximum resistance toward corrosion was observed for samples oxidized at 500 °C. This was attributed to the formation of a composite layer of oxides at this temperature comprising Ti2O3 (titanium sesquioxide), anatase and rutile phases of TiO2 on the surface of cp-Ti. Formation of an intact and pore-free oxide-substrate interface also improved its corrosion resistance. © 2017, ASM International.
Oral rehabilitation of segmental mandibulectomy patient with osseointegrated dental implant
(Medknow Publications, 2014) Archana Singh; Atul Bhatnagar; Rajesh Bansal; B.P. Singh
Surgical management of oral cancer lesions results in explicit aesthetic and functional disfigurement, including facial deformity, loss of hard and soft tissue, impaired speech, swallowing and mastication, which modify the patient's self-image and quality-of-life. Recent advances in head and neck reconstruction techniques and dental implant based prosthetic rehabilitation may significantly improve the quality-of-life and self-esteem for such post-surgery patients. This clinical report describes rehabilitation of oral cancer patient having segmental mandibulectomy with implant-supported fixed partial denture.
The effect of ball versus locator attachment system on the performance of implant supported overdenture: A systematic review
(Elsevier B.V., 2023) Nimmi Gupta; Rajesh Bansal; Neeteesh K. Shukla
Objective: This systematic review was aimed to compare ball and locator attachment system on the basis of clinical and biomechanical performance of implant supported overdenture as well as biological and patient related outcomes. Material and methods: Open and free electronic and manual searches were performed in digital databases including MEDLINE via PubMed, the Cochrane Database of Clinical Trials, and Scopus along with some other reliable sources. From the 667 retrieved records, 11 full-text controlled trials were included in this study. Risk of bias was assessed according to RoB 2.0 except for one RCT (economic evaluation), only assessed by CASP checklist. Results: From the 11 retrieved studies, total 183 locator and 219 ball attachments were identified in 452 subjects of 30 yrs–95 yrs of age. Studies provided data about prosthodontic complications or maintenance (replacement or the activation of matrix and patrix part, loss of retention, fracture and relining of the prosthesis, fracture of the attachment and the survival probability), oral health impact profile, soft tissue parameters and periodontal complications, marginal bone loss, patient related outcome and cost of the attachment systems. Only 5 studies were assessed at low risk bias, while other 6 at moderate to high risk of bias. Conclusion: Locator attachment system show lesser complications including loss of retention and lower maintenance appointments, lesser soft tissue, and periodontal complications than the ball attachment. Ball is better in terms of cost effectiveness. In other related outcomes, no significant differences were noted between ball and locator attachment. © 2022 The Authors
Whole genome sequencing reveals novel non-synonymous mutation in ectodysplasin A (EDA) associated with non-syndromic X-Linked dominant congenital tooth agenesis
(Public Library of Science, 2014) Tanmoy Sarkar; Rajesh Bansal; Parimal Das
Congenital tooth agenesis in human is characterized by failure of tooth development during tooth organogenesis. 300 genes in mouse and 30 genes in human so far have been known to regulate tooth development. However, candidature of only 5 genes viz. PAX9, MSX1, AXIN2, WNT10A and EDA have been experimentally established for congenitally missing teeth like hypodontia and oligodontia. In this study an Indian family with multiple congenital tooth agenesis was identified. Pattern of inheritance was apparently autosomal dominant type with a rare possibility to be X-linked. Whole genome sequencing of two affected individuals was carried out which revealed 119 novel non-synonymous single nucleotide variations (SNVs) distributed among 117 genes. Out of these only one variation (c.956G.T) located at exon 9 of X-linked EDA gene was considered as pathogenic and validated among all the affected and unaffected family members and unrelated controls. This variation leads to p.Ser319Ile change in the TNF homology domain of EDA (transcript variant 1) protein. In silico analysis predicts that this Ser319 is well conserved across different vertebrate species and a part of putative receptor binding site. Structure based homology modeling predicts that this amino acid residue along with four other amino acid residues nearby, those when mutated known to cause selective tooth agenesis, form a cluster that may have functional significance. Taken together these results suggest that c.956G.T (p.Ser319Ile) mutation plausibly reduces the receptor binding activity of EDA leading to distinct tooth agenesis in this family. © 2014 Sarkar et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.