call for papers, research paper publishing, where to publish research paper, journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJEI, call for papers 2012,journal of science and technolog
This document summarizes previous research on the deformation of endodontic obturator tips using finite element modeling (FEM). It discusses how FEM has been used to analyze stress distributions and deformation patterns in gutta percha cutter tips when subjected to thermal and mechanical loads. The document reviews literature on using tools like ANSYS to model different tip geometries and materials. It also discusses how FEM can help optimize tip design by predicting failure modes and analyzing stresses under various loading conditions. FEM is presented as an effective tool for analyzing complex dental structures when direct measurement is difficult.
Implant impressions- journal club - Accuracy of implant impressions using var...
This journal club deals with different impression techniques for implant restorations. These include two different impression techniques using different impression materials.
Comparison of root microcrack formation after root canal preparation using tw...
IOSR Journal of Dental and Medical Sciences is one of the speciality Journal in Dental Science and Medical Science published by International Organization of Scientific Research (IOSR). The Journal publishes papers of the highest scientific merit and widest possible scope work in all areas related to medical and dental science. The Journal welcome review articles, leading medical and clinical research articles, technical notes, case reports and others.
The document summarizes findings from 10 randomized controlled trials comparing different dental implant systems. The trials evaluated outcomes like failure rates, marginal bone loss, and peri-implant soft tissue health. Meta-analyses found no significant differences between systems in failures or bone loss over time, including between surface types. Subsequent follow-ups of initial trials continued finding no significant differences in long-term outcomes between major implant systems.
Abstract
The purpose of this study is to shows the usefulness of dental implant. In this paper include different types of abutments, tier
system and structure which is used in dental implant. In this study shows the types of connections of abutments.There are various
types of stresses which reason to diseases related dental implant. Forces act initially on the neck of dental implant. There are
many types of abutments which are used for fixation of crown. The main objective is to perform analysis of failure on dental
implant and post. The more focus of this study on abutment. Objective is to provide alternative solution to overcome on failure
due to infection, diseases which are comes after implant. This paper includes diseases.
Failures of dental implants are frequently clinical problems. So there is need of analysis of abutment in dental implant is
essential. Purpose of this study is analysis and process which used for evaluation of abutment and implant.
Key words:- Dental implant, stresses, abutment connection, Evaluation
This document discusses recent advances in removable partial dentures (RPDs). It begins with an introduction noting that while healthcare technology has advanced, RPD design and fabrication has not significantly changed since the 1950s. It then discusses pros and cons of various materials commonly used for RPDs like metals, flexibles, and acrylic. New high performance polymers and CAD/CAM systems for digital design and manufacturing of RPD frameworks are also covered. The use of polymers like PEEK and implant-assisted RPDs to improve support, retention and stability is summarized. The document concludes with a review of the literature on the accuracy of CAD-CAM systems for RPD frameworks and a clinical case report on the use of 3D-printed
Micro-computed tomographic assessment of dentinal microcrack formation in str...
Micro-computed tomographic assessment of
dentinal microcrack formation in straight and
curved root canals in extracted teeth prepared
with hand, rotary and reciprocating instruments IEJ 2021
1) A 10-year prospective study evaluated 121 oxidized titanium implants in 46 patients. 2) After 10 years, the survival rate was 99.2% with only 1 implant failing. 3) Marginal bone loss averaged 0.7 mm over 10 years, with 11.3% of implants showing over 2 mm of bone loss and 4.7% over 3 mm of bone loss. 4) Implants with over 3 mm bone loss showed bleeding and pus on probing, indicating peri-implantitis.
An Assessment on the Clinical Performance of Non-carious Cervical Restorationsasclepiuspdfs
This study evaluated the clinical performance of non-carious cervical lesion restorations placed at a university dental clinic over a 7-year period. A total of 121 restorations in 34 patients were assessed based on materials used (glass ionomer cement, resin composite, resin-modified glass ionomer cement) and clinical handling technique (with vs without cavity preparation). Glass ionomer cement restorations showed significantly better retention and less secondary caries compared to the other materials, but there were no differences in marginal integrity, discoloration, or anatomic form based on material. The clinical performance did not differ based on whether cavity preparation was used.
Implant impressions- journal club - Accuracy of implant impressions using var...Partha Sarathi Adhya
This journal club deals with different impression techniques for implant restorations. These include two different impression techniques using different impression materials.
Comparison of root microcrack formation after root canal preparation using tw...iosrjce
IOSR Journal of Dental and Medical Sciences is one of the speciality Journal in Dental Science and Medical Science published by International Organization of Scientific Research (IOSR). The Journal publishes papers of the highest scientific merit and widest possible scope work in all areas related to medical and dental science. The Journal welcome review articles, leading medical and clinical research articles, technical notes, case reports and others.
The document summarizes findings from 10 randomized controlled trials comparing different dental implant systems. The trials evaluated outcomes like failure rates, marginal bone loss, and peri-implant soft tissue health. Meta-analyses found no significant differences between systems in failures or bone loss over time, including between surface types. Subsequent follow-ups of initial trials continued finding no significant differences in long-term outcomes between major implant systems.
A review of dental implant problems and remedieseSAT Journals
Abstract
The purpose of this study is to shows the usefulness of dental implant. In this paper include different types of abutments, tier
system and structure which is used in dental implant. In this study shows the types of connections of abutments.There are various
types of stresses which reason to diseases related dental implant. Forces act initially on the neck of dental implant. There are
many types of abutments which are used for fixation of crown. The main objective is to perform analysis of failure on dental
implant and post. The more focus of this study on abutment. Objective is to provide alternative solution to overcome on failure
due to infection, diseases which are comes after implant. This paper includes diseases.
Failures of dental implants are frequently clinical problems. So there is need of analysis of abutment in dental implant is
essential. Purpose of this study is analysis and process which used for evaluation of abutment and implant.
Key words:- Dental implant, stresses, abutment connection, Evaluation
RECENT ADVANCES IN REMOVABLE PARTIAL DENTURESNAMITHA ANAND
This document discusses recent advances in removable partial dentures (RPDs). It begins with an introduction noting that while healthcare technology has advanced, RPD design and fabrication has not significantly changed since the 1950s. It then discusses pros and cons of various materials commonly used for RPDs like metals, flexibles, and acrylic. New high performance polymers and CAD/CAM systems for digital design and manufacturing of RPD frameworks are also covered. The use of polymers like PEEK and implant-assisted RPDs to improve support, retention and stability is summarized. The document concludes with a review of the literature on the accuracy of CAD-CAM systems for RPD frameworks and a clinical case report on the use of 3D-printed
Micro-computed tomographic assessment of dentinal microcrack formation in str...DR.AJAY BABU GUTTI M.D.S
Micro-computed tomographic assessment of
dentinal microcrack formation in straight and
curved root canals in extracted teeth prepared
with hand, rotary and reciprocating instruments IEJ 2021
A Novel Approach to Fracture Resistance Using Horizontal Posts after Endodont...Nadeem Aashiq
This case report describes a technique for reinforcing a tooth with horizontal fiberglass posts embedded in composite after endodontic therapy. A 40-year-old patient presented with pain in an upper right molar. After root canal treatment, two horizontal fiberglass posts were placed through holes drilled bucally and lingually and cemented with composite. At a 17-month follow-up the tooth remained asymptomatic and healed with the horizontal post restoration intact. A review found that horizontal posts can significantly increase fracture resistance compared to direct composite alone and result in more repairable fractures if failure occurs. The technique provides short-term reinforcement until a full-coverage restoration can be afforded.
1) Early crestal bone loss around dental implants is common, with an average of 0.9-1.6mm of bone loss in the first year after loading. Bone loss then slows significantly to around 0.05-0.13mm per year.
2) Factors that can contribute to early crestal bone loss include surgical trauma from heat generation during drilling, excessive pressure during implant placement, periosteal flap elevation, and occlusal overload especially in the first year as the bone adapts to loading.
3) Long-term maintenance of crestal bone is important for implant success and health of the surrounding soft tissues. Peri-implantitis can lead to bone loss but
The literature survey summarizes 10 research papers on dental implants coating. The papers cover various topics including the use of bone morphogenetic proteins like BMP-2 and BMP-7 to promote osseointegration as well as regeneration of periodontal tissues. Titanium and its alloys are widely studied as biomaterials for dental implants due to their biocompatibility and corrosion resistance. Surface modifications like anodization and hydroxyapatite coatings are shown to further enhance osseointegration. While BMP coatings show potential, more research is needed to define optimal delivery systems. Mechanical failures from screw loosening or fracture remain challenges. Long-term studies on porous titanium granules had unpredictable results with some implant
Experimental investigation on buckling of GFRP cylindrical shells subjected t...IOSR Journals
Composite cylindrical shells are being used in submarine, underground mines, aerospace applications and other civil engineering applications. Thin cylindrical shells are more prone to fail in buckling rather than material failure. An experimental study on buckling of glass fiber reinforced plastics layered composite cylindrical shells under displacement and load controlled static axial compression are reported The experimental results are compared with general purpose finite element program (ANSYS). Limit point loads evaluated for geometric imperfection magnitudes shows an excellent agreement with experimental results which clearly indicates the confidence gained on the numerical results presented. Present study finds direct application to qualitatively investigate the influence of geometric imperfection on other advanced grid-stiffened structures.
Experimental stress analysis and fea of dental implantseSAT Journals
Abstract Dental implants are used as prosthetic treatment alternatives made of Titanium for treating partial edentulism in patients. The
oessointegration of bone and implant at the interface is of utmost importance as the success or failure of a dental implant depends
on the manner in which stresses are transferred to the surrounding bone. The osseointegrated dental implant plays a role similar
to that of natural teeth as it is exposed to static and dynamic loadings continuously. However, the functional forces in
Osseointegrated dental implant are transmitted directly to the jaw bone as compared to the natural teeth where there is a healthy
periodontium. This could cause micro-fracture at the bone-implant interface, fracture of implant, loosening of components of
implant system and unwanted bone resorption. Therefore, it is essential to understand stress concentration on implants at the
bone implant interface. This study aims in investigating and monitoring the stresses along the bone implant interface for different
types of dental implant .Photo elastic stress analysis was carried on four commercial implants with varying diameter and same
length, and the verification of the experimental results was done using finite element analysis.
Keywords: Dental Implant, Photoelasticity, Stress Analysis, Implant Bone Interface, FEA
The IOSR Journal of Pharmacy (IOSRPHR) is an open access online & offline peer reviewed international journal, which publishes innovative research papers, reviews, mini-reviews, short communications and notes dealing with Pharmaceutical Sciences( Pharmaceutical Technology, Pharmaceutics, Biopharmaceutics, Pharmacokinetics, Pharmaceutical/Medicinal Chemistry, Computational Chemistry and Molecular Drug Design, Pharmacognosy & Phytochemistry, Pharmacology, Pharmaceutical Analysis, Pharmacy Practice, Clinical and Hospital Pharmacy, Cell Biology, Genomics and Proteomics, Pharmacogenomics, Bioinformatics and Biotechnology of Pharmaceutical Interest........more details on Aim & Scope).
All manuscripts are subject to rapid peer review. Those of high quality (not previously published and not under consideration for publication in another journal) will be published without delay.
This document contains a presentation on short dental implants given by Dr. Mohammed Alshehri at the ITI Congress Middle East in Abu Dhabi, UAE in December 2012. The presentation defines short implants, reviews the available evidence on their success rates compared to longer implants or bone augmentation procedures, and identifies factors that can affect the success of short implants such as surgical protocol, implant design, surface characteristics, crown-to-implant ratio and occlusal forces. Studies show short implants have high success rates, especially when placed in the mandible, and may be preferable to more complex augmentation procedures.
Do pre existing micro cracks play a role in the fracture resistance of roots ...Nadeem Aashiq
The document discusses a study that investigated whether pre-existing microcracks play a role in the fracture resistance of non-root filled mandibular incisors. Micro-CT was used to examine 60 teeth for microcracks. Teeth were then subjected to fracture testing. The results showed that 79% of teeth had microcracks, but the number of microcracks only explained 0.65% of the variance in fracture resistance. Most fractures did not correlate with microcrack location or position. The study concluded that there was no clear relationship between the presence of microcracks and fracture resistance of the teeth.
Journal club presentaion on zirconia fixed partial dentured on endodonticaloy...NAMITHA ANAND
The study investigated the effects of different post and core material combinations on surface strain of zirconia fixed partial denture (FPD) margins. Artificial abutment teeth were restored with either resin composite cores with glass fiber posts or cast metal alloy posts and cores. Strain gauges measured surface strain on the zirconia frameworks and abutment roots under static loading. The results showed that restoring the premolar with a cast post and core and the molar with a resin composite core reduced stress concentration in both the frameworks and abutment teeth compared to the other combination. The study suggests considering post and core material properties and differences in abutment tooth morphology when selecting materials for zirconia FPD
The document compares the low field electron transport properties in compounds of groups III-V semiconductors by solving the Boltzmann equation using an iterative technique. It calculates the temperature and doping dependencies of electron mobility in InP, InAs, GaP and GaAs. The electron mobility decreases with increasing temperature from 100K to 500K for each material due to increased electron-phonon scattering. Electron mobility also increases significantly with higher doping concentration at low temperatures. The iterative results show good agreement with other calculations and experiments. Electron mobility is highest in InAs and lowest in GaP at 300K, due to differences in their effective masses.
This document discusses methods for interpolating rainfall data using modified inverse distance weighting (MIDW) techniques. It examines four general forms of the MIDW method where the effects of distance and elevation difference can take positive or negative weights. The authors apply genetic algorithms to optimize the MIDW interpolation equation regionally and compare integrated vs. separated dimensionless weighting approaches. Daily rainfall data from 49 stations in the Mashhad plain catchment area of Iran over 16 years is analyzed. The results show that accounting for elevation improves interpolation and that regional optimization of the MIDW method leads to better performance than local optimization.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
This document presents a comparison of PID and fuzzy PID controllers for position control of a DC motor. It first describes the modeling of a DC motor transfer function. It then provides details on designing a PID controller using Ziegler-Nichols tuning methods. A fuzzy PID controller is also designed using triangular membership functions for error and change in error inputs. Simulation results in MATLAB/Simulink show that the fuzzy PID controller provides better tracking of setpoint changes with less overshoot compared to the ZN-tuned PID controller. The fuzzy PID controller therefore demonstrates better performance for position control of DC motors.
The document summarizes a research paper that proposes a new topology for a DSTATCOM (Distribution Static Compensator) to improve power quality in three-phase four-wire distribution systems. The proposed topology integrates a three-leg voltage source converter with a T-connected transformer. This helps mitigate neutral current and allows the DSTATCOM to compensate for load harmonics, reactive power, and imbalance. The design and control strategy of the DSTATCOM are described. Its performance is validated using MATLAB simulation for applications like power factor correction and voltage regulation along with neutral current compensation and harmonic reduction with nonlinear loads.
This document presents a framework for optimizing transportation costs when supplying resources to construction sites. It identifies renewable and non-renewable resources and considers the locations of storage facilities and construction sites. The objective is to minimize total transportation costs by determining optimal quantities to ship from each storage location to each site. A mathematical model is formulated to represent the transportation costs as a function of shipping quantities between sources and sinks, subject to supply and demand constraints. The model aims to develop a tradeoff between transportation costs and transshipment quantities for efficiently supplying resources in construction projects.
This document summarizes a research paper that proposes a fuzzy self-adaptive PID controller for temperature control of an electric heating furnace. It begins with an introduction to electric furnaces and challenges with using conventional PID controllers for nonlinear and time-varying temperature processes. It then describes tuning various PID controller gains using algorithms and comparing responses. Next, it designs a fuzzy logic controller and fuzzy-PID controller for the system using MATLAB/Simulink. Membership functions and fuzzy rules are defined for the fuzzy inference systems. The results show that the proposed fuzzy self-adaptive PID controller provides the best dynamic performance for temperature control of the electric furnace.
This document summarizes a research paper that proposes using the firefly algorithm to solve the NP-hard optimization problem of assigning cells in a cellular network to switches in a way that minimizes total costs. The total cost includes handoff costs for calls between adjacent cells and cabling costs for connecting cells to switches, subject to constraints like switch capacity. It describes modeling the problem mathematically and comparing the firefly algorithm to the particle swarm optimization (PSO) algorithm. The firefly algorithm is shown to solve the cell-to-switch assignment problem faster than existing approaches like PSO.
This document discusses implementing trust in cloud computing using public key infrastructure (PKI). It begins by providing background on PKI and how it uses public/private key cryptography to provide security services like authentication, confidentiality, and integrity. It then discusses cloud computing models and the Windows Azure platform. The paper proposes three trust models using PKI: 1) a public root CA and public CA, 2) a public root CA and enterprise CA, and 3) an enterprise root CA and enterprise CA. It details methodologies for implementing each model to establish trust between cloud services and customers. The enterprise root CA model provides the most security and trust but has higher costs and complexity.
This document summarizes a research paper that proposes using a particle swarm optimization (PSO) algorithm to design hybrid active power filters (HAPFs) for 3-phase 4-wire power systems with variable and nonlinear loads. The objectives are to minimize harmonic distortion, reactive power capacity, and costs while satisfying constraints. PSO is applied to find optimal filter parameters and component ratings. Simulation results show PSO designs outperform conventional trial-and-error methods in meeting standards for harmonic mitigation and power factor correction.
call for papers, research paper publishing, where to publish research paper, ...
Similar to call for papers, research paper publishing, where to publish research paper, journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJEI, call for papers 2012,journal of science and technolog
Comparative study between k-files use from stainless steel or nickel titanium...AD Dental
This study compared the manual widening of root canals with different degrees of curvature using Kerr file needles made of stainless steel or nickel-titanium alloy versus ProTaper cutters. The root canals were simulated with curvatures of 30, 45, 60, and 90 degrees and radii of 3, 4, and 5 mm based on 46 real patient cases. The results showed that Kerr files made of steel produced the greatest deviations from the natural root canal trajectory, while nickel-titanium alloy and ProTaper instruments produced less deviation. The highest modifications occurred with rigid instrumentation of extreme anatomies. Mathematically, nickel-titanium instruments, especially ProTaper, were shown to achieve more uniform widening of curved root
Ultrasonic inserts can be used for various applications in endodontics including surgical endodontics and non-surgical endodontics. Piezoelectric ultrasonic inserts vibrate linearly and are preferred over magnetostrictive inserts. They are classified based on design and use. Applications include root-end cavity preparation for surgery, removing obstructions like posts or separated instruments, and improving irrigant flow and effectiveness. Different tip designs are suited to specific tasks. Proper power settings and technique are important for safe and effective use.
This document provides an overview of ultrasonics in endodontics, including:
- A brief history of the development of ultrasonics in dentistry from the 1950s onward.
- An explanation of how ultrasonics works through magnetostriction and piezoelectric principles.
- Descriptions of the biophysical effects of ultrasonics such as acoustic streaming and cavitation.
- Guidelines for use and potential risks regarding pacemakers.
- Details about various ultrasonic tips used in endodontic procedures and their applications.
This document summarizes a study that evaluated the bond strength of two root canal filling systems (ActiV GP and gutta-percha with AH Plus sealer) when used with different irrigation protocols. Forty single-rooted teeth were divided into four groups based on the final irrigation used: EDTA, EDTA followed by chlorhexidine, MTAD, or MTAD followed by chlorhexidine. Each group was further divided based on the filling system used. Horizontal sections were taken and subjected to push-out testing to measure bond strength. The results showed that EDTA followed by chlorhexidine yielded the highest bond strength for ActiV GP. MTAD and MTAD followed by chlorhexidine adversely affected the
A Review on Modification in Honing Machine Stone Feeding InstallationIRJET Journal
This document summarizes a review on modifications made to the stone feeding installation on a honing machine. Honing is used to finish bearing surfaces and requires tool wear compensation to maintain surface finish quality during mass production. The existing manual stone feeding system was replaced with an automated mechanism using a ball screw actuator and stepper motor. This reduced human errors from operators and increased the number of bearing rings that could be honed. The review covers literature on tool wear monitoring methods like ultrasonic testing and sensor fusion, as well as tool wear prediction modeling. It was concluded that the new automated stone feeding system achieved the objectives of compensating for tool wear and improving honing machine productivity.
Finite Element Based Member Stiffness Evaluation of Axisymmetric Bolted Jointijiert bestjournal
For a reliable design of bolted joints,it is necessary to evaluat e the actual fraction of the external load transmitted through the bolt. The stiffness of the bolt and the me mber of the joint decide the fractions of external load shared by the bolt and the member. Bolt stiffness can be eval uated simply by assuming the load flow to be uniform across the thickness and the deformation is homogeneous. Then,bolt may be modeled as a tension member and the stiffness can be easily evaluated. But,the evalua tion of the member stiffness is difficult because of the heterogeneous deformation. In the present work,joint materials are assumed to be isotropic and homogeneous,and linear elastic axisymmetric finite element ana lysis was performed to evaluate the member stiffness. Uniform displacement and uniform pressure assumptions are employed in idealizing the boundary conditions. Wide ranges of bolt sizes,joint thicknesses,and material properties are considered in the analysis to evaluate characteristic behavior of member stiffness. Empiric al formulas for the member stiffness evaluation are proposed using dimensionless parameters. The results obtained are com pared with the results available in the literature.
Applications of ultrasonics in endodonticsMettinaAngela
This document discusses various applications of ultrasonics in endodontics. It covers topics like ultrasonic retreatment to remove gutta percha fillings, using ultrasonics for access refinement and to manage calcifications, removing separated instruments from the root canal, and retrieving old posts. Ultrasonics provides benefits for these procedures like more efficient removal of materials, enhanced safety and control, and minimal damage to tooth structure compared to other techniques. Specific tips, techniques and case reports are presented for different clinical applications of ultrasonics in endodontic retreatment and procedures.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This study compared the effects of 6 nickel-titanium rotary file systems (OneShape, ProTaper Universal, ProTaper Next, Reciproc, Twisted File Adaptive, and WaveOne) on root canal geometry changes in severely curved mesial root canals of mandibular molars. The root canals were scanned using cone-beam computed tomography before and after instrumentation to assess changes. The Reciproc system removed significantly more dentin than the OneShape, ProTaper Universal, and Twisted File Adaptive systems. However, there were no significant differences among the groups regarding transportation, curvature changes, surface area changes, or centering ability. All 6 file systems similarly straightened root canal curvature and produced similar canal transportation
This document discusses and compares several nickel titanium rotary root canal instrumentation systems, including Lightspeed, ProFile, EndoSequence, and K3. It provides details on their designs and evaluations of their efficacy, such as cleaning ability, preparation time, risk of ledging or instrument separation. Studies found that while rotary systems reduced preparation time compared to manual instrumentation, there were few differences in cleaning efficacy or healing of periapical lesions between methods. Later generation systems like EndoSequence and ProFile were found to have improved shaping ability and reduced risk of canal transportation.
Structural Health Monitoring of Fibre Reinforced Polymer Composite Leaf Springpaperpublications3
Abstract: The Structural Health Monitoring (SHM) has gained wide acceptance in the recent years as a means to monitor a structure and provide an early warning of an unsafe condition using real time data. Many researchers have shown that, Fiber Reinforced Polymer (FRP) composite leaf springs can be successfully used for suspension systems. This paper emphasizes on developing the SHM system for E-Glass/Epoxy FRP composite leaf springs based on strain sensing.
This document provides details of a project to analyze thermo-mechanical stresses in a tube sheet heat exchanger using finite element analysis software ANSYS. It includes details of the guiding staff, the research area of solar dryers, identified problems regarding stresses leading to failures, and a literature review summarizing previous related research on stress analysis of tube sheets. The work plan for phase 1 is to learn finite element methods and ANSYS to determine stresses, study factors influencing stresses, and conduct further literature review to aid the stress analysis, with ANSYS training planned for December 2013.
The purpose of this project is to design a system for Arbutus Medical that enables a commercially-available power tool to be used as a sterilizable, low-cost surgical saw.
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
The primary success metric of dental implants is achieving osseointegration, which is influenced by many factors including implant design, surface treatments, as well as treatment method. Implant drilling is also a major influential factor.
IRJET- Experimental Analysis of Circular Perforated Fin Arrays by Forced Conv...IRJET Journal
This document summarizes an experimental analysis of heat transfer from circular perforated fin arrays under forced convection using a wind tunnel. Trapezoidal microfin arrays with circular perforations were selected and designed using Taguchi Method. Experiments were conducted in a wind tunnel on three test specimens - a solid rectangular fin array and two trapezoidal perforated fin arrays with different perforation pitches. The perforated fin arrays showed higher overall efficiency and effectiveness compared to the solid fin array. Maximum overall efficiency was obtained for the array with 5mm perforation pitch at an air velocity of 2m/s and heat input of 150W. Optimum effectiveness was obtained for the array with 7mm pitch at 2m/s and 120W input
The document summarizes research on the self-adjusting file (SAF) system for root canal preparation.
[1] The SAF is a hollow file made of compressible nickel titanium that adapts to the cross-sectional shape of the canal. It removes dentin through a grinding motion with irrigation flowing continuously through it.
[2] Studies show the SAF prepares flat and oval canals more effectively than rotary files, removing up to 75 micrometers of dentin from the entire canal wall. It also induces less stress on root dentin than rotary files.
[3] The continuous flow of irrigant through the SAF improves disinfection by suspending more bacteria into the
The document discusses the self-adjusting file (SAF) system for root canal preparation. It describes the SAF's design as a hollow, compressible nickel titanium file that adapts to the canal shape. The SAF removes dentin through abrasive action and continuous irrigation while applying pressure. Studies found the SAF prepared canal walls more uniformly than rotary files, generated less stress on dentin, and was mechanically durable. The SAF was shown to effectively shape oval canals and remove bacteria from root canals.
The Niti rotary files have become the standard for the prepration of the root canal system because of their superelasticity they cause less canal transportation however shaping ability and resistance to cyclic fatigue fracture are of the special significance when evaluating the performance of Niti files .The shaping ability of Niti files depend on several factors such as taper,geometrical cross section,movement file system and alloy microstructure
Protaper Next File the newest to the protaper system which is the efficient solution for endo practitioner who seeking a versatile flexible system that will handle the vast majority of root canal treatment
This document discusses the use of ultrasound in endodontics. It describes two main methods of ultrasound production: magnetostriction and piezoelectric. Piezoelectric units are preferred as they produce linear motion without heat. Applications of ultrasound include access preparation, removing obstructions, activating irrigants, condensing gutta-percha, placing MTA, and surgical procedures like root-end cavity preparation and placement of root-end filling material. Ultrasound offers benefits like cleaner canals, less invasive surgery, and better filling of materials. A variety of tips are available for different procedures.
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This document discusses the impact of data mining on business intelligence. It begins by defining business intelligence as using new technologies to quickly respond to changes in the business environment. Data mining is an important part of the business intelligence lifecycle, which includes determining requirements, collecting and analyzing data, generating reports, and measuring performance. Data mining allows businesses to access real-time, accurate data from multiple sources to improve decision making. Using business intelligence and data mining techniques can help businesses become more efficient and make better decisions to increase profits and customer satisfaction. The expected results of applying business intelligence include improved decision making through accurate, timely information to support organizational goals and strategic plans.
This document presents a novel technique for solving the transcendental equations of selective harmonics elimination pulse width modulation (SHEPWM) inverters based on the secant method. The proposed algorithm uses the secant method to simplify the numerical solution of the nonlinear equations and solve them faster compared to other methods. Simulation results validate that the proposed method accurately estimates the switching angles to eliminate specific harmonics from the output voltage waveform and achieves near sinusoidal output current for various modulation indices and numbers of harmonics eliminated.
This document summarizes a research paper that designed and implemented a dual tone multi-frequency (DTMF) based GSM-controlled car security system. The system uses a DTMF decoder and GSM module to allow a car to be remotely controlled and secured from a mobile phone. It works by sending DTMF tones from the phone through calls to the GSM module in the car. The decoder interprets the tones and a microcontroller executes commands to disable the ignition or control other devices. The system was created to improve car security and accessibility through remote monitoring and control with DTMF and GSM technology.
This document presents an algorithm for imperceptibly embedding a DNA-encoded watermark into a color image for authentication purposes. It applies a multi-resolution discrete wavelet transform to decompose the image. The watermark, encoded into DNA nucleotides, is then embedded into the third-level wavelet coefficients through a quantization process. Specifically, the watermark nucleotides are complemented and used to quantize coefficients in the middle frequency band, modifying the coefficients. The watermarked image is reconstructed through inverse wavelet transform. Extraction reverses these steps to recover the watermark without the original image. The algorithm aims to balance imperceptibility and robustness through this wavelet-based, blind watermarking scheme.
1) The document analyzes the dynamic saturation point of a deep-water channel in Shanghai port based on actual traffic data and a ship domain model.
2) A dynamic channel transit capacity model is established that considers factors like channel width, ship density, speed, and reductions due to traffic conditions.
3) Based on AIS data from the channel, the average traffic flow is calculated to be 15.7 ships per hour, resulting in a dynamic saturation of 32.5%, or 43.3% accounting for uneven day/night traffic volumes.
The document summarizes research on the use of earth air tunnels and wind towers as passive solar techniques. Key findings include:
- Earth air tunnels circulate air through underground pipes to take advantage of the stable temperature 4 meters below ground for cooling in summer and heating in winter. Testing showed the technique can reduce ambient temperatures by up to 14 degrees Celsius.
- Wind towers circulate air through tall shafts to cool air entering buildings at night and provide downward airflow of cooled air during the day.
- Experimental testing of an earth air tunnel system over multiple months found maximum temperature reductions of 33% in spring and minimum reductions of 15% in summer.
The document compares the mechanical and physical properties of low density polyethylene (LDPE) thin films and sheets reinforced with graphene nanoparticles. LDPE/graphene thin films were produced via solution casting, while sheets were made by compression molding. Testing showed that the thin films had enhanced tensile strength, lower melt flow index, and higher thermal stability compared to sheets. The tensile strength of thin films increased by up to 160% with 1% graphene, while sheets increased by 70%. Melt flow index decreased more for thin films, indicating higher viscosity. Thin films also showed greater improvement in glass transition temperature. These results demonstrate that processing technique affects the properties of LDPE/graphene nanocomposites.
The document describes improvements made to a friction testing machine. A stepper motor and PLC control system were added to automatically vary the load on friction pairs, replacing the manual method. Tests using the improved machine found that the friction coefficient decreases as the load increases, and that abrasive and adhesive wear increased with higher loads. The improved machine allows more accurate and convenient testing of friction pairs under varying load conditions.
This document summarizes a research article that investigates the steady, two-dimensional Falkner-Skan boundary layer flow over a stationary wedge with momentum and thermal slip boundary conditions. The flow considers a temperature-dependent thermal conductivity in the presence of a porous medium and viscous dissipation. Governing partial differential equations are non-dimensionalized and transformed into ordinary differential equations using similarity transformations. The equations are highly nonlinear and cannot be solved analytically, so a numerical solver is used. Numerical results are presented for the skin friction coefficient, local Nusselt number, velocity and temperature profiles for varying parameters like the Falkner-Skan parameter and Eckert number.
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1. International Journal of Engineering Inventions
ISSN: 2278-7461, www.ijeijournal.com
Volume 1, Issue 4 (September 2012) PP: 19-26
Deformation Studies of Endodontic Obturator Tip Using FEM
Approach
Ratnakar R.Ghorpade1, Dr.Kalyana Sundaram2, Dr.Vivek Hegde3
1
Department of Mechanical Engineering, MAEER’s, Maharashtra Institute of Technology, Paud Road, Kothrud,
University of Pune, Pune-411 038.
2
Department of Mechanical Engineering,BRACT’s, Vishwakarma Institute of Technology,Bibwewadi,
University of Pune, Pune-411 037.
3
Department of Conservative Dentistry & Endodontics, M.A.Rangoonwala College of Dental Sciences &
Research Centre, Pune – 411 001.
Abstract––Heated Cutter tips are used by dental surgeons extensively for treating root canal and other obturation
procedures. Biocompatible Cutter design involves challenges of both structural and thermal loads in the vicinity of the
root canal area . Natural gutta percha is very similar to natural rubber, which is mainly used as filler material to seal off
the prepared root canal cavity against bacterial infections. The cutter is being used to heat, soften, condense and cut off
the excess gutta percha from the apical region of tooth crown with ease. The Gutta Percha Cutter Tip geometry is selected
initially based on ideal root canal geometry available. The cutter tip is being heated by a suitable heating mechanism to
300˚C for 3 to 5 seconds. There is cyclic effect of heating tip temperatures on inner point in tip. Thermo-mechanical
analysis of Gutta Percha Cutter tip is carried out in ANSYS10.0, which gives the combined stress pattern and
deformation pattern on the tip. FEA is a proven cost saving tool and can reduce design cycle time therefore it can be used
as accurate tool to investigate thermo-mechanical stress and deformation pattern on cutter tip, and it will ensure minimal
effects of combined stresses in tip on the inner wall of prepared root canal cavity.
Keywords––Gutta Percha, ANSYS10.0, FEA.
I. INTRODUCTION
1.1 Problem Statement:-
Gutta percha is a natural isoprene polymer extracted from the resin and sap of the trees of the Palaquium family,
which grow mainly in south-east Asia. Natural gutta percha is very similar to natural rubber, it is mainly used as filler
material to seal off the prepared root canal cavity against bacterial infections. The cutter is being used to heat, soften,
condense and cut off the excess gutta percha from the apical region of tooth crown with ease. The objective of this paper is
to evaluate critical failure safety of the cutter used for dental surgery.
1.2 Methodology:-
The design of Gutta percha cutter tip, challenges the creativity of the designer to use knowledge of solid geometry
with liberty, based on his/her own experience to avoid tooth interference, and knowledge of optimization practices. FEA is a
proven cost saving tool and can reduce design cycle time and therefore can be used as accurate tool to investigate thermo-
mechanical stress and deformation pattern on cutter tip. Our work in this paper is directed towards optimizing the tip
geometry for defined cutting load and given heat pattern on tip surface. We also sought to predict the range of deformation
possible due to combined effect of thermal stress and stress due to cutting load.
1.3 Description :
The Gutta Percha Cutter Tip geometry is modeled based on an idealized root canal assumed for a typical molar
tooth. The cutter tip is heated to 300 degree Celsius for 3 to 5 seconds and is left to natural cooling during usage on the
cavity. Here it cools down after transferring the heat to the gutta percha. Heat is continuously supplied to the gutta percha tip
by a suitable mechanism. Thus temperatures on inner point in tip, the cutting force on tip surface, are the inputs for the
analysis. Thermo-mechanical analysis of Gutta Percha Cutter tip is carried out in ANSYS10.0, which gives the combined
stress pattern and deformation pattern on the tip. Further based on this analysis the data were used to make design decisions.
1.4 Analysis :-
The results obtained from FEA helps designers to take decisions on the design safety and also to optimize it by
analyzing the design for available different materials. FEA acts as a tool for analyzing different Tip geometries for current
study. It also saves time and also simplify complexity involved in analysis of element i.e. tip in the biomedical device. FEA
also helps us to analyze and better understand various critical sections and to predict the failure mode.
19
2. Deformation Studies of Endodontic Obturator Tip using FEM Approach
II. LITERATURE SURVEY
Prior work on the Gutta Percha cutter tip reveals that a “wedging effect” created by the intracanal forces
developed during obturations which can be measured using a force analyzer device i.e. Endogramme (measures Force vs
Time that permits the comparison of different obturation techniques.Thus it provides a new approach to the analysis of
intracanal forces ). The wedging effect is the forces resulting from the hydrostatic pressure which is developed by a plugger
while it is pushing gutta-percha into a canal. Assumption: hydrostatic pressure assumed equal in all direction i [1].
The modified Endographe, with a new cupule, a force analyzer device is used to compare the forces and wedging
effects developed in the root canal using four obturation techniques: warm vertical compaction, lateral condensation,
thermomechanical compaction, and Thermafil condensation. The mean values for the wedging effect for warm vertical
compaction, lateral condensation, thermomechanical compaction, and Thermafil condensation were, respectively, 0.65 ±
0.07 kg, 0.8 ± 0.1 kg, 0.6 ± 0.08 kg, and 0.03 ± 0.01 kg. ii [2]
Stress distribution patterns i.e. Radicular stresses during obturation and root stresses during occlusion loading,
were investigated in simulated biomechanically prepared mandibular first premolars with four different tapers at two
different compaction forces and an occlusal load with finite element analysis. FEA used for numerical analysis of complex
structures to determine the stress and strain distribution pattern in the internal structure of tooth. Assessment of stress levels
by measuring deformation patterns (using photoelastic method, strain gauges, Instron Universal machine) inside the root
canal is extremely difficult , therefore FEA have been utilized to address these difficulties and gain insight into internal
stress distributions. Assumptions and input data for FEA: i) A straight root was chosen for this study in order to eliminate
effects due to canal curvature. ii) Guttapercha were compacted by vertical condensation technique in three separate vertical
increments (apical 1/3, middle 1/3, cervical 1/3). iii) Vertical compaction forces of 10N and 15 N are used for each
increment, applied by simulated plugger. iv) Periodontal ligament layer is assumed to be 200μm thick v) A surrounding bone
volume to support the root were created. vi) Simulated standard access opening made in the crown. vii) Root canals with 2%,
4%, 6%, & 12% taper created out of which 4% & 6% were chosen for clinical relevancy. 12% tapered canal chosen
arbitrarily to simulate the effects of excessive canal preparation. viii) Model with apical preparation of 0.35 mm at the point
of constriction, 0.5 mm (from what would be clinically perceived as the radiographic apex). ix) Isotropic properties applied
for Dentine (D), Periodontal ligament (PDL), Supporting bone volume (B), Gutta percha (GP). PDL modeled as a soft
incompressible connective layer ( to approximate fluid behavior). x) Coefficient of friction between GP and root canal wall
were selected as 0.1 to 0.25. xi) Warm GP compacted in three vertical increments until the canal was filled, at the start of
compaction a temperature of 60 ˚C, reduced to 37˚C during filling procedure. xii) Plugger surface was assumed to have
rounded edges and a tip diameter of 0.5 mm ( smaller than the canal diameter) at each compaction increment. Conclusion:
During simulated obturation, root stresses decreased as the root canal taper increases and stresses were greatest at the apical
third and along the canal wall. The fracture resistance of the restored endodontically treated tooth is a function of the
strength of the root (taper of prepared canal) and remaining coronal tooth structure. The clinician must make a decision to
use instruments which have an inherently larger or smaller taper based on the architecture present in a given canal. The
development of new design features such as varying tapers, noncutting safety tips and varying length of cutting blades in
combination with the metallurgic properties of alloy nickel-titanium have resulted in a new generation of instruments and
concepts. Additional in-vivo and in-vitro tests and clinical trial are desirable in order to elucidate the accuracy of finite
element analysis. [3]
The ultimate goal of endodontic treatment is to preserve the tooth in normal function as long as possible. Stress
distributions were investigated in a mandibular second premolar by using a commercially available 3-dimensional finite
element analysis software program (MSC Patran 2007 r1a and MSC Marc 2007r1; The original tooth model was adapted to
construct the other tooth models with varying degrees of curvature (15, 30, and 45 degrees. A standard access opening was
made in the crown, and a round root canal preparation was created with 0.04 taper and a final apical preparation of size 35.
The models also simulated a cylindrical section of normal bone 2 mm from the cementoenamel junction and a periodontal
ligament space 200 μm thick. All bonds at the interface between dentin and post materials were assumed to be perfect
bonds.All posts were assumed to leave 4–5 mm of gutta-percha root filling apically. Each model was meshed by structurally
solid elements defined by nodes having 6 degrees of freedom in tetrahedral bodies (MSC Patran 2007 r1a).Isotropic
properties were applied for all materials. Displacement of all nodes on the lateral surface and base of the supporting bone
was constrained. A cementum layer was not incorporated into the models because it was too thin to be simulated accurately,
and its modulus of elasticity is close to that of dentin. All conditions can be kept identical (such as tooth morphology,
mechanical properties, load, and periodontal support). The numeric method ensures that the root canal preparation has the
same size and taper in each model, which would have been impossible to achieve in an experimental study in human teeth.
Stress distribution in clinical situation is no longer uniform, Root canal shape and root morphology also affect the stress
distribution, resulting in an increased tensile stress on the internal root canal wall. The results in this study are presented in a
qualitative rather than a quantitative manner. [4]
From the computational point of view, only three studies (E. Berutti, G. Chiandussi, I. Gaviglio, and A. Ibba, X.
Xu and Y. Zheng, S. Necchi, S. Taschieri, L. Petrini, and F. Migliavacca) based on finite element analyses (FEA) were
conducted, aiming to evaluate some aspects of the mechanical behavior of the instruments (e.g., the stress distribution)
related to their critical condition during root canal instrumentation and not assessable through laboratory or in vivo tests.
Authors carried out extensive research based on their previous findings by comparing the mechanical performance of three
different Ni-Ti alloys, when used to produce rotary endodontic instruments.Modeling and Analysis: Rhinoceros 2.0
Evaluation (Used to create geometrical model), ABAQUES 6.5-1/ standard (Used for computational Analysis).
Considerations: The handle part of the file does not serve any specific function in the shaping procedure, and therefore it was
neglected in the numerical analyses.Model meshing: 10-nodes tetrahedral elements. And canals were meshed using 4-node
bilinear elements. Element & node optimization: A grid sensitivity study was performed to choose the most convenient
20
3. Deformation Studies of Endodontic Obturator Tip using FEM Approach
number of elements (in terms of computational time and results accuracy). The canals were modeled as simple rigid surfaces
shaped as pipes, based on radius, angle, and position of curvature. In this work, four types of canal geometries were
considered, characterized by a radius r of 2 or 5 mm, an angle a of 45˚ or 30˚, and an apical or middle position (p) of the
curvature. The modeled instruments were forced into the root canals until the apex was reached (insertion step) and
immediately retrieved (removal step). as a first approach to the problem, neither friction nor machining action was
considered between the instrument blade and the canal wall. A „„soft‟‟ contact with an exponential pressure-overclosure
model was imposed to simulate their interaction. Hence, the torsional stresses induced in the file during the procedure were
neglected. The primary curvature parameter influencing the mechanical behavior of the instrument (higher variations of
strain) is the radius of curvature. Differently, the second dominant parameter is judged the position of curvature for the Ni-Ti
alloys and the angle of curvature for the stainless steel. The stainless steel instruments showed a lower ability to conform to
the canal shape during an entire insertion-removal cycle. In particular, the tip of the stainless steel file plasticized just after
the first contact with the canal wall. The Ni-Ti file bends uniformly along the blade, following the original curvature of the
canal. FEA are recognized to have an important role in optimizing the behavior of biomedical devices. [5]
After obturation, a vertical load was applied by means of spreader inserted into the canal until fracture
occurred.Forces encountered during lateral condensation alone should not be a direct cause of vertical root fracture. Load
generated during lateral condensation is less than the load required to fracture the root.GP compaction in root canal achieved
by attaching hand spreader tip (Hu- friedy) to Instron Testing machine (Model 4206, Instron Corp. Canton MA). Fracture
loads varies from 5 kg to 24.3 kg. Mean Fracture load obtained by Lertchirakarn et al for mandibular premolar was 9.7 kg.
Factors influencing the fracture: i) Root canal shape with reduced radius of curvature is the single most important factor
influencing the location and the direction of fracture lines. ii) External root morphology. iii) Dentine thickness iv) Oval root
canal Fracture occurs when the tensile stress in the canal wall exceeds the ultimate tensile strength of dentin. When an apical
pressure is applied with a round instrument (D11 Hand spreader) inserted into an elliptical canal, it will bind at its narrowest
width, which is typically from mesial to distal. The initial forces will be directed towards the mesio-distal direction leading
to a strain on the bucco-lingual surface. Hence the resulting fracture lines will orient in the bucco-lingual direction. [6]
To calculate the stress in the tooth, surrounding periodontal ligament, and in the alveolar bone when a lower first
premolar is subjected to intrusion or torque movement using a constant moment. Model was subjected to an intrusive force
on the premolar of 0.5 N and a lingual root torque of 3 Nmm. The extent of changes in tissue structures was proportional to
the amount and duration of applied forces and moments. The main resorption occurred at the root apex.The tooth is
constructed as a hollow body with a consistent thickness of 0.2 mm. Young‟s modulus of the tooth is much greater than that
of the periodontal ligament. Young‟s modulus of the bone is clearly greater (1.000– 10.000-times) than that of the
periodontal ligament. The exact geometry of the periodontal ligament space could not be quantified because of its slight
width.Parameters for the linear, elastic mechanical properties of the tooth (consisting of enamel and dentin), periodontal
ligament (the Young‟s modulus varies) and alveolar bone. Capillary blood pressure in PDL ranges between 15 & 35 mm Hg
( i.e.0.002 – 0.0047 MPa), Meshing: 8 noded hexagonal elements ( as stability much better than tetrahedrons). PDL
undergoes greatest deformation (as being softest tissue, thus high element density is used for it.). Force: Fz = -0.25 N (on
lingual and labial sides of tooth crown), Fz = -0.5 N ( as intrusive force). Maximums and minimums of the hydrostatic stress
portion at the apex and alveolar crest. Further research need: It is as yet impossible to measure the stress inside the
periodontal ligament in-vivo. Stress and strain in this area can only be calculated using the finite element method. There has
not been sufficient quantitative investigation so far concerning the connection between forces and movement.It is still
impossible to evaluate all the factors influencing resorption. Orthodontic forces represents only one cofactor affecting root
resorption. [7]
A marked decrease of instantaneous shear modulus was observed at the melting point, and the range of the first-
order transition temperature at heating was from 420C to 600C. Also A marked specific volume change was observed at the
first-order transition temperature. During the setting process, the crystallization of gutta percha is thus thought to adversely
affect the sealing ability in the root canal space. The main cause of endodontic treatment failure is generally said to be
incomplete sealing of the root canal, and accordingly it is important to obturate the root canal closely. Fluidity and melting
point can be altered by arranging the content, the average molecular weight and molecular weight distribution, but a large
amount of volumetric shrinkage with crystal growth cannot be avoided when using gutta percha. The technique using melted
gutta percha alone may not be favourable compared with conventional lateral condensation because melted gutta percha
undergoes a large amount of shrinkage during setting. [8]
The findings of preliminary studies showed that the force required to provide a significant increase in the diameter
of heated gutta-percha specimens should be greater than 3 kg. Further research is required to increase the accuracy and
standardisation of the analysis of the thermoplastic properties of guttapercha and similar root canal filling materials. Few
studies have focused on the differences between commercially available brands of guttapercha,no specific methodology for
testing the thermoplasticity of gutta-percha has been described.[9]
In endodontic therapy, dental gutta-percha is plasticized by a heat carrier or by thermomechanical compaction,
which if used improperly may cause partial decomposition if the heat generated exceeds 100°C, according to the Merck
index. Root canal filling techniques must use temperature control (between 53°C and 59°C) permitting the β-phase gutta-
percha to change into the α-phase, avoiding the gutta-percha amorphous phase. gutta-percha in the β-phase begins the α-
phase change when heat reaches the temperature range of 48.6°C to 55.7°C, and that the α-phase material changes to the
amorphous phase when heated between 60°C and 62°C. The heat source must be carefully used and the condenser should be
heated only for a few seconds before condensing and cutting the obturation material; if overheated, periodontal damages
might occur. Heating dental gutta-percha to 130°C causes physical changes or degradation. [10]
Heating up to 130˚C causes chemical-physical changes of the gutta-percha; this is due to the presence of additives
(70–80%), which alter the behaviour of the material. For this reason, the dimensional stability of the filling materials is not
21
4. Deformation Studies of Endodontic Obturator Tip using FEM Approach
guaranteed. The mass loss in gutta-percha polymer could make the cone material more porous and could reduce its root-
canal sealing property. [11]
III. MATHEMATICAL MODELING OF CUTTER TIP
3.1 Mathematical model
The device under study can be handheld portable apparatus used to heat, soften & cut gutta percha as filler material
with ease and also fill it in root cavity without disturbing patient. The cutter tip is modeled as tapered bar loaded at smaller
end (i.e. free end) with a force „P‟ and fixed at the bigger end, in order to determine its deformation behavior.
Fig. 1 Solid Model of Dental device with cutter tip Fig. 2 The basic structure of the tooth, with the infected part,
that needs to be cleaned. Also, the root canal of the tooth can be seen.
Fig. 3 Gutta Percha cutter tip geometry under study
D: Diameter at larger end (i.e.at fixed end „A‟), (mm)
d: Diameter at smaller end (i.e.at free end „B‟), (mm)
P: Load at the free end of tapered bar, (N)
lx: Length of tapered bar, (mm)
l: Length of smaller diameter from point „C‟, (mm)
L: Length of fixed end/larger diameter from point „C‟, (mm)
x-x: Any cross section along the bar at distance „x‟ from point „C‟,
dx: Diameter at section x-x, (mm)
Mx-x: Bending moment at section x-x, (N-mm)
Ix: Moment of inertia at section x-x,
E: Young‟s Modulus. (N/mm2)
Taper lines are extended to meet at point „C‟
Diameter at section x-x:
For uniformly varying cross-sectional area,
22
5. Deformation Studies of Endodontic Obturator Tip using FEM Approach
M -------------------(1)
can be rearranged as
-------------------(2)
Solution of above equation for deflection is,
------------------(3)
Where, k= (64.P.l4)/π.d4 ----------------- (4)
3.2 Flowchart to find the deflection at any point on the tapered bar loaded at it’s end (smaller end) and fixed at the
bigger end:
Start
Read P,l,d,E,x,L
k= (64.P.l4)/π.d4
]
Print „y‟
End
3.3 Analytical Solution:
Fig. 4 Deflection plot (Analytical Solution)
IV. FINITE ELEMENT ANALYSIS OF CUTTER TIP
4.1 FEA Basis:
The plugger is introduced for 3-4 mm into the gutta-percha cone (this also must not touch the dentinal walls),
where it remains for a fraction of a second and is then removed. In actual practice, the probe of the Touch‟n Heat unit is
introduced into the orifice, started and allowed to plunge 3-4 mm into the coronal most extent of the gutta-percha. The heat-
activating element is then released and after hesitating momentarily, the cooling instrument is removed, along with an
adhered bite of gutta-percha. In this manner, the gutta-percha is heated around the heat-carrier and about 3-4 mm apically
(no more, because gutta-percha is not a conductor of heat. When the instrument is withdrawn from the root canal,
simultaneously a bite of gutta-percha has remained attached to it and is then removed.
A new introduction of the heat-carrier will then remove another bite of gutta-percha, moving more apically the level of
compaction. Now the assistant will hand the smallest plugger, to compact the softened material in the most apical portion of
the root canal.
23
6. Deformation Studies of Endodontic Obturator Tip using FEM Approach
a. b. c. d.
Fig. 5 Heat Softening & Compaction of Gutta Percha by Cutter Tip in steps
a. The heatcarrier is returned, which is introduced into the center of the gutta-percha cone in the root canal.
b. The heat-carrier is heating the gutta-percha apically to its tip and removes the surrounding material from the canal.
c. A new introduction of the heatcarrier is softening the gutta-percha in the apical one third.
d. Another piece of gutta-percha has been removed. Now it is time to use the smallest plugger,
4.2 Assumptions and input data for FEA:
i) A straight root was chosen for this study in order to eliminate effects due to canal curvature.
ii) Guttapercha were compacted by vertical condensation technique in three separate vertical increments (apical 1/3,
middle 1/3, cervical 1/3).
iii) Vertical compaction force of 10N is used for each increment, applied by simulated plugger.
iv) Warm GP compacted in three vertical increments until the canal was filled, at the start of compaction a
temperature of 60 ˚C, reduced to 37˚C during filling procedure.
v) Plugger surface was assumed to have flat and a tip diameter of 0.2 mm ( smaller than the canal diameter) at each
compaction increment.
vi) The handle part of the cutter does not serve any specific function in the shaping procedure, and therefore it was
neglected in the numerical analyses.
4.3 Finite Element Analysis:
Analysis tool: ANSYS 10.0
Material Properties used for NiTi Tips in FEA:Young‟s Modulus: 83GPa, Poisson‟s ratio: 0.33
Model Meshing:
BEAM element of class BEAM 44, (3D Tapered element for structural analysis).
Loads & constraints:
Structural loading: Tip is loaded at it‟s end in transverse direction by a compaction force of 10 N. As the tip is joined to NiTi
pipe at it‟s bigger end, it is constrained for the displacement in the three directions at this end.
4.4 FEA Results:
2.5
2
1.5
Deflection, mm
y = -2.125x + 2.226
1 R² = 0.791
0.5
0
0 0.5 1 1.5
-0.5
Tapered Bar Diameter, mm
Fig. 6 FEA Solution for deflection of tapered bar for 10 N Fig. 7 Deflection plot (FEA Solution)
24
7. Deformation Studies of Endodontic Obturator Tip using FEM Approach
Table 1: Analytical & FEA solution for deflection of 10 mm
long tapered bar at various diameters along it’s length when
loaded at smaller free end by 10 N
Distance Diameter Deflection Deflection Analytical & FEA solution for 10 N load
from (mm) (mm) (mm) 3
free end Analytical FEA
(mm) Solution Solution 2.5
Upper line(Blue):Analytical Solution
x= 0 0.2 2.993315 Lower Line (Red): FEASolution
0.5 0.28 2.449849 2.3609 2
1.5 0.38 1.603915 1.5507
Deflection, mm
2.5 0.48 1.043858 0.99342 1.5
3.5 0.58 0.670952 0.63630
4.5 0.68 0.419134 0.40121 1
5.5 0.78 0.248644 0.24401
6.5 0.88 0.134983 0.13902 0.5
7.5 0.98 0.062444 0.07061
8.5 1.08 0.020558 0.028752 0
0 0.2 0.4 0.6 0.8 1 1.2
9.5 1.18 0.002104 0.0067579 Tapered Bar Diameter, mm
10 1.2 0 0
Fig. 8 Analytical and FEA Solution for 10 N load
4.5 Thermal Expansion in the material:
For the cutter tip of length 10 mm, 15 mm and 20 mm the thermal expansion is 0.016917 mm, 0.0253755 mm and
0.033834 mm respectively. It is based on
dl = L0 α (t1 – t0) ---------------------------------------- (5)
where, dl = change in length (mm)
L0 = initial length (mm)
α = linear expansion coefficient ( 7.9X10-6)
t0 = initial temperature (oC)
t1 = final temperature (oC)
V. CONCLUSION
Structural deformation behavior of the Endodontic cutter tip is analyzed based on analytical approach & FEA approach. The
results obtained (Maximum deflection at the cutter tip end observed to be 2.449849 mm analytically, and 2.3609 mm by
FEA), which are closely matching, and could be further utilized in analyzing the effect of stressing the tip on the root canal
cavity. Thus the optimum balance between cutting force on tip and friction force on Gutta percha surface in contact with the
root canal wall is required, while compacting gutta percha in the cavity. It will ensure minimal effects of combined stresses
in tip on the inner wall of prepared root canal cavity. Thus FEA of tip of the Gutta Percha Cutter helps us to standardize to
certain extent the design procedure for the Tip which will have minimum stress effects on inner wall of the root canal cavity.
ACKNOWLEDGMENT
We would be thankful to Dr.Vivek Hegde, (MDS),(Consultant Endodontist & Cosmetic Dentist, Master in Lasers, Vienna),
Professor & Head of Department of Conservative Dentistry & Endodontics, M.A.Rangoonwala College of Dental Sciences
& Research Centre, 2390, K.B.Hidayatulla Road, Azam Campus, Pune – 411 001, for providing necessary inputs during
continual phase of research.
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26