Effectiveness and safety of rotary and reciprocating kinematics for retreatment of curved root canals: a systematic review of in vitro studies

Simões Lucas Pinho,Reis-Prado Alexandre Henrique dos,Bueno Carlos Roberto Emerenciano,Viana Ana Cecília Diniz,Duarte Marco Antônio Húngaro,Cintra Luciano Tavares Angelo,Lemos Cleidiel Aparecido Araújo 대한치과보존학회 2022 Restorative Dentistry & Endodontics Vol.47 No.2

Objectives This systematic review (register-osf.io/wg7ba) compared the efficacy and safety of rotary and reciprocating kinematics in the removal of filling material from curved root canals. Materials and Methods Only in vitro studies evaluating both kinematics during retreatment were included. A systematic search (PubMed/MEDLINE, Scopus, and other databases, until January 2021), data extraction, and risk of bias analysis (Joanna Briggs Institute checklist) were performed. Efficacy in filling removal was the primary outcome. Results The search resulted in 2,795 studies, of which 15 were included. Efficacy was measured in terms of the remaining filling material and the time required for this. Nine studies evaluated filling material removal, of which 7 found no significant differences between rotary and reciprocating kinematics. Regarding the time for filling removal, 5 studies showed no difference between both kinematics, 2 studies showed faster results with rotary systems, and other 2 showed the opposite. No significant differences were found in apical transportation, centering ability, instrument failure, dentin removed and extruded debris. A low risk of bias was observed. Conclusions This review suggests that the choice of rotary or reciprocating kinematics does not influence the efficacy of filling removal from curved root canals. Further studies are needed to compare the kinematics safety in curved root canals. Objectives This systematic review (register-osf.io/wg7ba) compared the efficacy and safety of rotary and reciprocating kinematics in the removal of filling material from curved root canals. Materials and Methods Only in vitro studies evaluating both kinematics during retreatment were included. A systematic search (PubMed/MEDLINE, Scopus, and other databases, until January 2021), data extraction, and risk of bias analysis (Joanna Briggs Institute checklist) were performed. Efficacy in filling removal was the primary outcome. Results The search resulted in 2,795 studies, of which 15 were included. Efficacy was measured in terms of the remaining filling material and the time required for this. Nine studies evaluated filling material removal, of which 7 found no significant differences between rotary and reciprocating kinematics. Regarding the time for filling removal, 5 studies showed no difference between both kinematics, 2 studies showed faster results with rotary systems, and other 2 showed the opposite. No significant differences were found in apical transportation, centering ability, instrument failure, dentin removed and extruded debris. A low risk of bias was observed. Conclusions This review suggests that the choice of rotary or reciprocating kinematics does not influence the efficacy of filling removal from curved root canals. Further studies are needed to compare the kinematics safety in curved root canals.

Estimation of WorldSID thorax kinematics using multiple 3-axis accelerometers

박예섭,오유근 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.12

It is essential to analyze the kinematics of anthropometry dummy in vehicle’s crash test. In general, it is required to measure the linear and angular components in the three orthogonal directions, respectively, in order to calculate the 3D kinematics of a rigid body. The WorldSID is originally designed to measure the tri-axis linear accelerations at the first (T1), fourth (T4), and twelfth (T12) thoracic vertebrae segments and the angular accelerations in the x and z directions. However, only three tri-axis linear accelerations are often measured for the sake of convenience. The lack of the required information results in the inaccurate calculation of the 3D torso kinematics. In this study, we propose an algorithm to accurately estimate the 3D torso kinematics when only three tri-axis linear accelerations at T1, T4, and T12 are available. Given the fact that the three tri-axis accelerometers are fixed in the torso segment, the mathematical algorithm is developed to estimate the linear acceleration at the location of the center of mass for the torso and the angular acceleration of the torso. The accuracy of the proposed algorithm is validated against the results from a rigid-body model that models the WorldSID’s spine block and tri-axis accelerometers attached to T1, T4, and T12. According to the comparison against the rigid-body model, the estimated values are calculated to be within 1.7 % of the target values. After the validation is achieved, the 3D kinematics of WorldSID’s torso is estimated using a set of actual side impact test data. In conclusion, the proposed algorithm accurately estimates the 3D WorldSID kinematics when at least three sets of tri-axis linear accelerations are available without any measurements of angular components.

기하학적인 방법을 이용한 3 Rotary 형식 5축 가공기의 후처리 방법

윤재득(Jaedeuk Yun),정융호(Yoongho Jung),박도현(Dohyun Park) (사)한국CDE학회 2009 한국CDE학회 논문집 Vol.14 No.5

This paper presents a post-processing algorithm for 5-axis machines with three rotary axes (3R-2L type). 5-axis machining needs the postprocessor for converting cutter location (CL) data to machine control (NC) data. The existing methods for post-processing use inverse kinematics equations from forward kinematics. However in case of 5-axis machines with three rotary axes, the inverse kinematics equations are not induced directly since the forward kinematics equations are non-linear. In order to get the joint values from the forward kinematics equations, previous algorithms use numerical method for the post-processing, which needs searching algorithms with computation time and may result in fail. This paper proposes a geometric method for the post-processing of 3 rotary type 5-axis machines. Our algorithm has three advantages: first, it does not need establishing forward kinematics equations. Second, it is reliable method that eliminates any numerical methods for the inverse kinematics, resulting in the exact solution. Finally, the proposed algorithm can also be applied to 2R-3L type of 5-axis machines.

기구학적 분석을 이용한 로봇 매니퓰레이터 개발

민병로(Min Byeong-Ro),이대원(Lee Dae-Weon) (사)한국생물환경조절학회 2004 생물환경조절학회지 Vol.13 No.1

본 연구는 오이수확기의 매니퓰레이터 개발을 위한 기구학적 분석을 하는 것이다. 매니퓰레이터의 정방향 기구학 및 역방향 기구학 분석을 한 후 실제 장치의 반복오차 측정실험을 통해 이론 값을 검증하였다. 매니 퓰레이터는 총 세 개의 링크로서 한 개의 수직링크와 두개의 회전링크로 구성되어져 있으며, 세 개의 스테핑 모터가 각 관절에 장착되어 링크에 동력을 전달한다. 주요 연구결과를 요약하면 다음과 같다. D-H Parameter를 이용하여 정방향 기구학에 의한 매니퓰레이터의 변환 연산자를 얻었다. 역방향 기구학의 해는 두가지로 나타났으며 삼각함수를 이용하여 해를 구하였다. 매니퓰레이터의 반복오차를 측정한 검증 실험에서는 X, Y, Z축에 대하여 반복 오차가 최대 2.60 ㎜, 2.05 ㎜, 1.55 ㎜로 나타났으며, 정방향 및 역방향 기구학에서 오차의 최대지점 및 최소지점의 실제 좌표는 일치하였다. 반복오차 측정 결과는 매니퓰레이터의 목표지점인 오이의 직경에 비해 비교적 작게 나타났다. 측정오치는 실험중 발생한 실험오차로 판단된다. 매니퓰레이터의 오차를 줄이고 작업능률의 향상을 위해서는 링크의 수를 줄이고 오이의 품종 및 재배환경을 고려하여야 하며, 경량이면서도 견고한 재료를 사용하여 하중을 줄여야 한다. This study is kinematics for the manipulator development of cucumber harvesting. A theory value was verified by repeated error measurement after the forward kinematics or inverse kinematics analysis of manipulator. Manipulator is consisted of one perpendicular link and two revolution link. The transformation of manipulator can be valued by kinematics using Denavit-Hartenberg parameter. The value of inverse kinematics which is solved by three angles faction shows two types. Repeated errors refered maximum 2.60 ㎜, 2.05 ㎜ and 1.55 ㎜ according to X, Y, Z axis. In this study, the actual coordinates of maximum point and minimum point were agreement in the forward kinematics or inverse kinematics. The results of repeated error measurement were reflect to be smaller compared to a diameter of cucumber. measurement errors were determined by experimented errors during the test. For reducing errors of manipulator and improving work efficiency, the number of link should be reduced and breeding and cultural environment should be considered to reduce the weight and use the hard stuff. The velocity of motor for working should be considered, too.

세 개의 회전축을 가진 5축 밀링 가공의 NC 데이터 후처리 방법

윤재득(Jae-Deuk Yun),정융호(Yoong-Ho Jung),김태경(Tae-Gyeong Kim) 한국생산제조학회 2009 한국공작기계학회 추계학술대회논문집 Vol.2009 No.-

We present a postprocessing algorithm for 5-axis machines, which can be applied to 2 rotary axes (2R-3L) types and 3 rotary axes (3R-2L) types. Five-axis machining requires a postprocessor for converting cutter-location (CL) data to machine-control (NC) data. The existing methods for postprocessing use inverse kinematics equations from the forward kinematics. However, for 5-axis machines with three rotary axes, the inverse kinematics equations cannot be induced directly, because the forward kinematics equations are nonlinear. To derive the joint values from the forward kinematics equations, previous algorithms use numerical methods for the postprocessing; this requires a search algorithm with much computation time and may fail to obtain a solution. We propose a general method for the postprocessing that can be applied to both 2-rotary and 3-rotary 5-axis machines. Our algorithm has three advantages: first, the forward kinematics equations are not required; second, the method is reliable and eliminates the need for numerical methods for the inverse kinematics, which results in exact solution; and finally, the proposed algorithm can also be applied to 2R-3L 5-axis machines.

수치적인 역운동학 기반 UKF를 이용한 효율적인 중간 관절 추정

서융호(Yungho Seo),이준성(Junsung Lee),이칠우(Chilwoo Lee) 大韓電子工學會 2010 電子工學會論文誌-SP (Signal processing) Vol.47 No.6

영상 기반의 모션 캡처에 대한 연구는 인체의 특징 영역 검출, 정확한 자세 추정 및 실시간 성능 등의 문제를 풀기 위해 많은 연구가 진행되고 있다. 특히, 인체의 많은 관절 정보를 복원하기 위해 다양한 방법이 제안되고 있다. 본 논문에서는 수치적인 역운동학 방법의 단점을 개선한 실시간 모션 캡처 방법을 제안한다. 기존의 수치적인 역운동학 방법은 많은 반복 연산이 필요하며, 국부최소치 문제가 발생할 수 있다. 본 논문에서는 이러한 문제를 해결하기 위해 기존의 수치적인 역운동학 해법과 UKF를 결합하여 중간관절을 복원하는 방법을 제안한다. 수치적인 역운동학의 해와 UKF를 결합함으로써, 중간 관절 추정 시 최적값에 보다 안정적이고 빠른 수렴이 가능하다. 모션 캡처를 위해 먼저, 배경 차분과 피부색 검출 방법을 이용하여 인체의 특징 영역을 추출한다. 다수의 카메라로부터 추출된 2차원 인체 영역 정보로부터 3차원 정보를 복원하고, UKF와 결합된 수치적인 역운동학 해법을 통해 동작자의 중간 관절 정보를 추정한다. 수치적인 역운동학의 해는 UKF의 상태 추정 시 안정적인 방향을 제시하고, UKF는 다수의 샘플을 기반으로 최적 상태를 찾음으로써, 전역해에 보다 빠르게 수렴한다. A research of image-based articulated pose estimation has some problems such as detection of human feature, precise pose estimation, and real-time performance. In particular, various methods are currently presented for recovering many joints of human body. We propose the novel numerical inverse kinematics improved with the UKF(unscented Kalman filter) in order to estimate the human pose in real-time. An existing numerical inverse kinematics is required many iterations for solving the optimal estimation and has some problems such as the singularity of jacobian matrix and a local minima. To solve these problems, we combine the UKF as a tool for optimal state estimation with the numerical inverse kinematics. Combining the solution of the numerical inverse kinematics with the sampling based UKF provides the stability and rapid convergence to optimal estimate. In order to estimate the human pose, we extract the interesting human body using both background subtraction and skin color detection algorithm. We localize its 3D position with the camera geometry. Next, through we use the UKF based numerical inverse kinematics, we generate the intermediate joints that are not detect from the images. Proposed method complements the defect of numerical inverse kinematics such as a computational complexity and an accuracy of estimation.

Geometric Postprocessing Method for 5-axis Machine Tools using Locations of Joint Points

윤재득,정융호,Thomas Kurfess 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

We present a postprocessing algorithm for 5-axis machines, which can be applied to types with two rotary axes (2R-3L) and three rotary axes (3R-2L). Five-axis machining requires a postprocessor for converting cutter-location (CL) data to numerical-control (NC)data. The existing methods for postprocessing use inverse kinematics equations from the forward kinematics. However, for 5-axis machines with three rotary axes, the inverse kinematics equations cannot be induced directly, because the forward kinematics equations are coupled. To derive the joint values from the forward kinematics equations, previous algorithms use iterative numerical methods for the postprocessing; this requires a search algorithm with much computation time and may fail to obtain a solution. Our algorithm has three advantages: first, the forward kinematics equations are not required; second, the method is reliable and eliminates the need for numerical methods for the inverse kinematics, which results in exact solutions; and finally, the proposed algorithm is generic for 5-axis machines, which can also be applied to 2R-3L 5-axis machines.

A Geometric Postprocessing Method for 5-axis Machine Tools using Locations of Joint Points

Yun, Jaedeuk,Jung, Yoongho,Kurfess, Thomas 한국정밀공학회 2013 International Journal of Precision Engineering and Vol.14 No.11

We present a postprocessing algorithm for 5-axis machines, which can be applied to types with two rotary axes (2R-3L) and three rotary axes (3R-2L). Five-axis machining requires a postprocessor for converting cutter-location (CL) data to numerical-control (NC) data. The existing methods for postprocessing use inverse kinematics equations from the forward kinematics. However, for 5-axis machines with three rotary axes, the inverse kinematics equations cannot be induced directly, because the forward kinematics equations are coupled. To derive the joint values from the forward kinematics equations, previous algorithms use iterative numerical methods for the postprocessing; this requires a search algorithm with much computation time and may fail to obtain a solution. Our algorithm has three advantages: first, the forward kinematics equations are not required; second, the method is reliable and eliminates the need for numerical methods for the inverse kinematics, which results in exact solutions; and finally, the proposed algorithm is generic for 5-axis machines, which can also be applied to 2R-3L 5-axis machines.

Three-dimensional Kinematic Analysis of the Yurchenko Layout with 360-degree Twist in Female Vaults: Deterministic Model and Judges` Scores

( Cheol-hee Park ),( Young-kwan Kim ) 한국운동역학회 2017 한국운동역학회지 Vol.27 No.1

Objective: The purpose of this study was to identify kinematic variables that govern successful performance and judges` scores and to establish correlative relationships among those of Yurchenko layout with a full twist in female vaults. Method: Four video cameras with sampling rate of 60 Hz collected 32 motion data of Yurchenko vaults from twenty-two female participants (age: 18.6 ± 3.6 years, height: 153.0 ± 6.5 cm, mass: 44.7 ± 7.3 kg) during national competition. Posting processing and calculations of kinematic variables were performed in Kwon 3D XP and Matlab<sup>®</sup> programs. Correlation and regression analyses were applied to find the relationships between the obtained scores and kinematic variables. Deterministic model (Hay & Reid, 1988) was used to investigate the strength of correlative relationships among kinematic variables. Results: The obtained scores from the judges` decision were mainly affected by post-flight peak height, horse contact time, knee angle at landing, and horse takeoff angle. Strong blocking during horse contact was required to get successful performance and obtain high scores. Modified deterministic model showed that round-off entrance and takeoff angles and resultant velocity of the center of mass (CM) during the roundoff phase were the starting variables affecting performance in the following kinematics. Knee angle at landing, a highly influential variable on the obtained point, was only determined by judges` decision without significant correlative relationship with previous kinematic variables. Conclusion: The obtained scores highly depended on kinematic variables of post-flight and horse contact phases that were affected by those from the previous phases including round-off postures and resultant velocity of the body center of mass.

Relationships of Kinematics and Obtained Points in Female Yurchenko Stretched 360° Twist Technique

( Cheol-hee Park ),( Ji-yong Joo ),( Young-kwan Kim ) 한국체육학회 2016 국제스포츠과학 학술대회 Vol.2016 No.1

Purpose: This study was based on female horse competition at 2015 National Championship Games in Gwangju. It was purposed to investigate the relationship of kinematic results in Yurchenko stretched 360° twist technique and the obtained points of athletes in order to find which kinematic variable(s) would be deterministic factor(s) to judges’ scores. Method: Twenty-two athletes (age: 18.64±3.62 years, height: 153.00±6.45cm, mass: 44.73±7.31kg) performed Yurchenko stretched 360° twist technique in the competition. Four video cameras having 30Hz of sampling rate were used to capture 33 trials of Yurchenko technique from 22 athletes. Acquired video files were edited at video-editing software. Fifteen anatomical landmarks were manually digitized on Kwon 3D XP program since there was no reflective marker on the body of subjects due to competition situations. Digitized data were used to calculate kinematic variables associated with Yurchenko technique. Result: Results indicated that high scored subjects showed higher resultant velocity of center of mass (CM) at the take-off from the horse. The subjects having high scores showed higher knee angles and pelvic angle as well as lower take-off angle at horse take-off than low-scored subjects. However, the twist angular velocity of high scored subjects was lower than that of low scored subjects at the moment of horse take-off. In the correlation analysis, there were negative correlations between obtained scores and movement times of round phase and board phase, respectively. In the first flight phase, there was no relation between kinematics and obtained scores. The obtained scores had significantly negative correlations with horse contact time, horizontal CM displacement, horse take-off angle, and twist angular velocity at the horse take-off. Whereas, the obtained scores had significantly positive correlations with CM resultant velocity, peak vertical height, and landing knee angle during the second flight. Only CM resultant velocity and peak vertical height were significantly affected by previous kinematics. Conclusion: In conclusion, the obtained scores were partially determined by kinematic results across individual phases. Especially judges’ determination dominantly depended on the landing knee angle. It is recommended that the higher CM resultant velocity, shorter horse contact time, and higher peak height of the second flight are needed to make successful Yurchenko stretched 360° twist technique.