Search

Background/Aim. The clinical success of prosthetic rehabilitation that commences after the attained implant osseointegration is dependent on the influence of several factors, of which screw loosening is a frequent one, and it is highly related to inadequate tightening (torquing) using torque wrenches. Although the wrenches are initially calibrated by the manufacturer, it is of great importance to evaluate their function after usage for a certain period of time. The aim of this study was to evaluate the accuracy and repeatability of the performance of implant torque wrenches in delivering necessary torque values before and after one year of usage. Methods. Two types of wrenches were used in the study: the beam-type and the toggle-type. Four various brands of beam-type wrench were marked as Beam 1 - Beam 4, and three various brands of toggle-type wrench were marked as Toggle 1 - Toggle 3, according to their design. Torque values delivered by wrenches were measured and analyzed using the One-Sample t-test, Independent-Samples t-test, and Mann-Whitney U test. The Bland-Altman bias test was used as an index of accuracy, whereas Forkman's comparison of datasets coefficients of variation (CV) served as an index of repeatability. Results. All wrenches except new Beam 2 and Beam 3 showed differences between the average measured torque value and target torque value. Differences were found in the average measured values between all used and new wrenches. Higher bias was observed in Toggle 1, Toggle 2, and Toggle 3 brands, whereas lower bias was recorded between used and new Beam 1 and Beam 3 wrenches. When comparing the CV for used and new wrenches, Beam 1, Beam 4, Toggle 1, and Toggle 2 revealed differences, whereas the CV for Beam 2, Beam 3, and Toggle 3 did not differ significantly. Conclusion. Compared to toggle-type, the beam-type wrenches offer greater accuracy in achieving the target torque value. The torque deteriorates in all wrenches after aging/usage and is more prominent in toggle-type devices. [ABSTRACT FROM AUTHOR]

In past decades, the success rates of the first dental implant treatments were low (75%). Nowadays, oral rehabilitation with titanium dental implants has a high success rate (95%–98%). The success rate significantly increases due to increased scientific knowledge about osseointegration, changes in surgical techniques, and the development of implant surface treatments. Despite the high success rate of implants, there are no protocols to define the time for the prosthesis to be installed, the insertion torque, and the prosthesis loaded after surgery. This work compares a new dental implant's primary (mechanical) and secondary (osseointegration) stability. Dental implants with micro- and nano-roughness surfaces were placed in 24 patients with a minimum of 35 N·cm and a maximum of 60 N·cm. Primary stability was quantified with a torque wrench and an Ostell Mentor Device. The secondary stability 45 and 60 days after surgery was measured with Ostell. The results showed no statistical difference in secondary stability at 45 and 60 days postoperatively among implants. The success rate of dental implants can be associated with the surface morphology with micro- and nano-roughness, the insertion torque value, and the shape of the implant threads. When the manufacturer's guidelines are followed, it is possible to prosthetically rehabilitate the patient with an implant 45 days after surgery. [ABSTRACT FROM AUTHOR]

This article discusses the relevance of dental torque wrenches in implant dentistry and the potential influence of their use. The accuracy of measurements made by dental torque wrenches and their possible complications are explored. The article highlights the importance of using appropriate techniques and instruments for successful implant procedures. It also discusses the different methods of recording the reference scale of dental torque wrenches and the challenges that arise when the scale becomes unreadable. The authors emphasize the need for proper care and maintenance of precision instruments and suggest that the industry should develop products with extended useful life and maintained precision. [Extracted from the article]

Objective: Achieving successful fusion during spine surgery is dependent on rigid pedicle screw fixation. To assess fixation strength, the insertional torque can be measured during intraoperative screw fixation. This study aimed to explore the technical feasibility of measuring the insertional torque of a pedicle screw, while investigating its relationship with bone density. Methods: Thoraco-lumbar screw fixation fusion surgery was performed on 53 patients (mean age, 65.5 ± 9.8 years). The insertional torque of 284 screws was measured at the point passing through the pedicle using a calibrated torque wrench, with a specially designed connector to the spine screw system. The Hounsfield units (HU) value was determined by assessing the trabecular portion of the index vertebral body on sagittal computed tomography images. We analyzed the relationship between the measured insertional torque and the following bone strength parameters: bone mineral density (BMD) and HU of the vertebral body. Results: The mean insertion torque was 105.55 ± 58.08 N·cm and T-score value (BMD) was -1.14 ± 1.49. Mean HU value was 136.37 ± 57.59. Screw insertion torque was positively correlated with BMD and HU in whole patients. However, in cases of osteopenia, all variables showed very weak correlations with insertional torque. In patients with osteoporosis, there was no statistically significant correlation between BMD and torque strength; HU showed a significant correlation. Conclusion: The insertional torque of screw fixation significantly correlated with bone density (BMD and HU). HU measurements showed greater clinical significance than did BMD values in patients with osteoporosis. [ABSTRACT FROM AUTHOR]

This in vitro study investigates the limit of expansion forces and torque wrench forces developed by five skeletal bone expander designs (MICRO 2/4 expanders™) for clinical application. A total of 30 skeletal expanders were placed in artificial bone blocks and mechanically tested, simulating maxillary expansion. Differences in jackscrew (Dentaurum™ [D], Superscrew™ [S] and Powerscrew™ [P]), number of orthodontic mini-implants (OMIs; two or four) and their placement inclinations (parallel 0° or 10° inclination) form five designs (D4/10°, S4/0°, S4/10°, P4/10° and P2/10°). Expansion forces and torque wrench values were registered, and radiographs were made initially and after 4 mm of expansion. Stress-strain curves were obtained after successive activations and the statistical analysis was performed as appropriate. Plastic deformations in the OMIs and jackscrew occurred around the activation numbers 11–13, with torque wrench values in the range of 500–700 cN. The maximum expansion forces in expanders with four OMIs varied from 93.0 (D4/10°) to 166.6 N (P4/10°) whereas two OMI expanders (P2/10°) registered forces of 79.4 N. Radiographs revealed during loads bending forces (S4/00°, S4/10°) with jackscrew and OMIs deformation in a convex shape, and shear forces (P4/10°, P2/10°) demonstrated only OMIs deformation in a concave shape, providing 15% more expansive force. The jackscrew D4/10° did not have any deformation, but its wire key did not allow reliable activations from activation number 10 and compared to S4/10° and P4/10°, these expanders provided greater expansion forces (P = 0.000 and P = 0.032, respectively). The different results obtained in stability and expansion forces indicate that if the activations are carried out under extreme conditions, they may have clinical importance with deformations and non-working expansion mechanics. Jackscrew designs play an important role in expansive forces and expander stability. Torque wrench values can be used clinically as a tool to asses the expansion forces and to avoid deformations. [ABSTRACT FROM AUTHOR]

In cementless total hip arthroplasty, the rotational stability of the stem is generally confirmed in a one-time manual evaluation by the surgeon. This study was performed to evaluate the sequential intraoperative changes in rotational stability using a torque wrench. Primary total hip arthroplasty was performed on 52 consecutive hips using a single wedge stem design. Intraoperative evaluation of rotational stability was uniformly performed using a torque wrench. Evaluations were performed immediately after broach insertion and immediately before the final insertion of the stem (after placement of the acetabular cup). Immediately after the insertion of the broach, rotational stability was checked and confirmed to be fully stabilized using a torque wrench in all cases, and the stability was maintained in 17 of 52 (33%) hips immediately before the final insertion of the stem. Among the hips showing instability, 11 of 35 (31%) broaches were upsized, while the remaining 24 hips achieved stabilization through deeper insertion of the broach. In conclusion, the rotational stability achieved immediately after the insertion of the broach was not necessarily maintained during surgery, indicating that rotational stability may need to be checked at multiple time points intraoperatively. [ABSTRACT FROM AUTHOR]

This paper introduces an innovative bolt-free preloaded inter-module connection for steel-framed modular buildings, referred to as the 'AJ' connection. It provides the vertical connection between columns by engaging a preload induced by long steel rod bolts (SRB) and specially designed couplers. The preload is applied using a torque or impact wrench. Consequently, the connection simplifies the on-site assembly and disassembly processes of the modular building, thereby enhancing both construction speed and reusability of modules. In this study, the structural performance of the AJ connection was investigated experimentally and numerically. First, the coupler was tested under a uniaxial tensile load to check its strength. Then, preloading tests on assemblies of a coupler and a 3m long SRB were conducted to determine the torque-preload relationship. Subsequently, full-scale beam-to-column joints featuring the AJ connection were tested under monotonic loading to investigate its lateral-force resisting mechanism. Lastly, the seismic performance of the AJ connection was investigated using FE joint models calibrated against a combination of test results and geometric and material nonlinear analyses with imperfections (GMNIA). A comparative analysis with a welded connection was also conducted to evaluate the seismic performance of the AJ connection. The findings indicated that the AJ connection demonstrates seismic performance comparable to the welded connection, exhibiting Strong column-Weak beam behaviour for seismic moment-resisting frames. Additionally, it satisfies the ductility requirements for structures of ductility class DCM as specified by EN 1998–1. • Developed a novel preloaded inter-module connection for steel modular buildings. • The connection enhances construction speed and module reusability. • Assessed experimentally the connection, including preloading and joint tests. • Assessed numerically seismic performance of the connection using FE models. • The connection satisfies the ductility class medium as specified by EN 1998–1. [ABSTRACT FROM AUTHOR]

The construction of low damage, self-centering, unbonded post-tensioned seismic systems requires special techniques and equipment such as hydraulic jacks to stress tendons that may not be readily available in developing communities. The recently proposed spring anchored rocking system (SARS) uses a spring at the anchorage of the post-tensioning tendon to facilitate applying force to the tendons using simple techniques such as torque wrenches. The seismic behaviour of the SARS is investigated using finite element models developed in OpenSees. The self-centering lateral force resisting system of a 3-story timber structure was anchored with springs having four different configurations, and subjected to a set of 22-pair ground motions. The finite element models consisted of elastic beam column elements to model the frame members, nonlinear truss element to model the post-tensioning tendon, spring element to model the anchorage of the tendon, and gap element to model the spring closure. It is found that the spring at the post-tensioning anchorage introduces flexibility, reduces the tendon force, and generally increases the rigid body deformations of the SARS compared to conventionally anchored systems using nuts set on bearing plates. [ABSTRACT FROM AUTHOR]

Background A subcutaneous implantable cardioverter defibrillator (S-ICD) has several advantages over the transvenous ICD, including a reduced risk of lead-related mechanical complications and infection. However, inappropriate shock therapy is one of the most common adverse events associated with S-ICDs. We herein report a case of inappropriate shock therapy of S-ICD due to incomplete sealing of the seal plug. Case summary A 60-year-old man, who had been on haemodialysis with a history of myocardial infarction, was transferred to the hospital after successfully being resuscitated from ventricular fibrillation (VF). An S-ICD was implanted for secondary prevention. On the third and the seventh post-operative days, S-ICD shock therapy was delivered without any tachyarrhythmias. As device interrogation revealed reproducible noises in both the secondary and alternate vectors by tapping at the generator, the sensing vector was fixed to the primary vector. Two months after discharge, the patient died of VF after receiving appropriate S-ICD shock delivery seven times. The S-ICD was retrieved from the body, and it was revealed that the seal plug had incompletely sealed and returned to its normal closed position after reinsertion of a torque wrench. Discussion Seal plug damage is a rare complication but should be considered if noise oversensing is provoked only at the secondary and/or alternate vectors. In the present case, the inappropriate shock therapy might have been prevented if we had checked the seal plug carefully. Therefore, we advocate confirming the seal plug routinely after the removal of the torque wrench. [ABSTRACT FROM AUTHOR]

Background and Objectives: Using an appropriate torque to tighten set screws ensures the long-term stability of spinal posterior fixation devices. However, the recommended torque often varies between different devices and some devices do not state a recommended torque level. The purpose of this study is to evaluate the effect of set screw torque on the overall construct stability and fatigue life. Materials and Methods: Two commercial pedicle screw systems with different designs for the contact interface between the set screw and rod (Group A: plane contact, Group B: line contact) were assembled using torque wrenches provided with the devices to insert the set screws and tighten to the device specifications. The axial gipping capacity and dynamic mechanical stability of each bilateral construct were assessed in accordance with ASTM F1798 and ASTM F1717. Results: Increasing or decreasing the torque on the set screw by 1 Nm from the recommended level did not have a significant effect on the axial gripping capacity or fatigue strength of Group A (p > 0.05). For Group B, over-tightening the set screw by 1 Nm did cause a significant reduction in the fatigue strength. Conclusions: Excessive torque can damage the rod surface and cause premature failure. When insertion using a manual driver is preferred, a plane contact interface between the set screw and rod can reduce damage to the rod surface when the set screw is over-torqued. [ABSTRACT FROM AUTHOR]

Purpose: To compare the tightening torque accuracy of three electronic torque drivers.Materials and Methods: Three electronic torque drivers were assessed using two measurement methods-pure output torque (POT) and clinical output torque (COT). For both methods, assessments were performed at set torques of 10, 20, 30, and 40 Ncm, 10 times for each setting, with each driver tested. Appropriate statistical analysis was performed according to data distribution (ie, normal vs non-normal) (α = .05).Results: POT was significantly higher than COT at a set torque of 30 Ncm (P < .001).Conclusion: In fastening an implant screw at 30 Ncm, the operator should also consider the output torque generated in the electronic torque driver. [ABSTRACT FROM AUTHOR]

This paper introduces a novel bolt-free preloaded column-to-column connection, termed the 'AJ connection', for steel-framed modular buildings. The AJ connection is classified as a post-tensioned inter-module connection, and modules are connected vertically by preload, using specially designed couplers and high-tensile steel rod bolts (SRB) within the columns. The AJ connection enables easy assembly and disassembly processes of modular buildings by inducing preload on top of the modules using a torque or impact wrench, thus improving construction speed and reusability. The paper also establishes a design method, not previously attempted in the literature, to determine the minimum necessary preload for the connection. The primary aim of this method is to design against potential failures by gap-opening and slip between modules, commonly associated with existing post-tensioned inter-module connections. The effectiveness of the suggested method is verified through numerical simulations using FE joint models that have been calibrated against monotonic loading test results. Furthermore, the study investigates the adverse effects of gap-opening and slip at the connection on the performance of the beam-to-column joint and the SRBs within the columns. The findings indicate that (i) minimising the difference between the flexural stiffness of the floor and ceiling beams reduces the impact of gap-opening, and (ii) the rotation of the coupler caused by plate bearing due to slip prior to gap-opening affects the induced preload in the SRBs and leads to premature gap-opening at the connection. • Developed a novel bolt-free post-tensioned connection for steel modular buildings. • The connection improves construction speed and module reusability. • Established a design method to determine the minimum necessary preload. • Validated the effectiveness of the design method using FE joint models calibrated against test results. • Investigated adverse effects of gap-opening and slip at the connection. [ABSTRACT FROM AUTHOR]

Professor James Davenport FBCS has been awarded a BCS Honorary Fellowship. Brian Runciman MBCS spoke to him about his work with BCS, his academic achievements, and what BCS has meant to him. [ABSTRACT FROM AUTHOR]

The suspension strut mount plays a crucial role in any vehicular suspension system, where it acts as a connector (bolted) to the vehicular body and suspension strut. The mount's purpose is to cushion the Vehicular impacts and reduce the jarring effect, noise, and vibration caused due to vehicle movement over the undulated roads. The self-loosening of bolts results because of the up and down impact of the spring cause the jounce bouncer to push and pull action at the mount interface, cause vibrations transmitted to the vehicle camber. Self-loosening leads to damage of mount followed by clunking noises, noisy steering, tire misalignment, and can cause discomfort to the passenger. Therefore, condition monitoring and assessment of an upper strut mount is necessary for vehicles. This paper studies the feasibility of the piezo Impedance-based Structural health monitoring (SHM) technique to monitor the self-loosening bolts in the upper strut mount of the suspension system (MacPherson strut suspension) of passenger car. The piezo coupled signatures were obtained experimentally by loosening all the three bolts (connected to strut bearing) through control torques through a digital torque wrench. All the experimental signatures were acquired with a single PZT patch bonded to the surface of the upper strut mount for loosening bolts with pre-tight loss. Progressive damage scenarios are simulated along with preload loss of either single bolt or all three bolts, respectively. Three different statistical damage indices were evaluated for damage quantification raised due to bolt loosening. A 3D numerical modeling of strut mount is done using ANSYS WORKBENCH, and piezo impedance signatures were acquired (hence converted to admittance) for validating the experimental signatures. In an overall, this study provides an insight into the loss of structural integrity due to the self-loosening of suspension bolts, which can be threatful to vehicular integrity. [ABSTRACT FROM AUTHOR]

The article deals with the methodology of verification of mechanical and electronic torque gauges. Legislative metrological requirements are set for these gauges and the verification process for these types of gauges is also set. The working standard is used to verify two selected torque gauges and then the suitability of these gauges is assessed. Measurement uncertainties are identified to determine the reliability of the measurement process. [ABSTRACT FROM AUTHOR]

Objectives: To compare the accuracy of implant placement performed with either a surgical motor or a torque wrench as part of a half-guided surgical protocol. Materials and methods: Implant insertion with half-guided surgical protocol was utilized by surgical motor (machine-driven group) or torque wrench (manual group) in the posterior maxilla. After the healing period, accuracy comparison between planned and actual implant positions was performed based on preoperative cone beam computed tomography and postoperative digital intraoral scans. Coronal, apical, and angular deviations, insertion time, and insertion torque were evaluated. Results: Forty patients were treated with 1 implant each; 20 implants were inserted with a surgical motor and 20 implants with a torque wrench. Global coronal and apical deviations were 1.20 ± 0.46 mm and 1.45 ± 0.79 mm in the machine-driven group, and 1.13 ± 0.38 mm and 1.18 ± 0.28 mm in the manual group (respectively). The mean angular deviation was 4.82 ± 2.07° in the machine-driven group and 4.11 ± 1.63° in the manual group. Mean insertion torque was 21.75 ± 9.75 Ncm in the machine-driven group, compared to 18.75 ± 7.05 Ncm in the manual group. Implant placement duration was 9.25 ± 1.86 s in the machine-driven group at a speed of 50 rpm, and 36.40 ± 8.15 s in the manual group. Conclusion: No significant difference was found between the two groups in terms of accuracy and mean insertion torque, while machine-driven implant placement was significantly less time-consuming. Clinical relevance: Optimal implant placement accuracy utilized by half-guided surgical protocol can be achieved with both machine-driven and torque wrench insertion. Trial registration: ID: NCT04854239 [ABSTRACT FROM AUTHOR]

At present, the common method to realize the pre-tightening effect of threaded fasteners is by applying an accurate tightening torque on them. However, when removing the tightening torque, the load characteristics will have a transient conversion, so that the pre-tightening loads will be significantly different from the tightening condition. For the aim of understanding the pre-tightening effect under the service condition, it is important to model the load conversion between tightening and service conditions. Based on the most basic mechanical equilibrium analysis, the load characteristics of bolt-nut fasteners under a round of the tightening and service conditions were studied. The torque equilibrium equations were built respectively, the load conversion between two conditions was analyzed and an approximate relationship between the applied tightening torque under the tightening condition and the pre-tightening torque under the service condition was obtained. In the meanwhile, a dynamic strain measuring system was proposed to accurately determine the pre-tightening loads in real time. Results verified that the thread torque and the bearing friction torque balance each other and act as pre-tightening torques under the service condition. The final pre-tightening loads can be roughly estimated to be larger than half of the difference in tightening torques by wrenches, but smaller than half of the sum of tightening torques, or can be accurately measured through dynamic strain measurements. Highlights: • We study on bolt-nut fasteners,load characteristics under tightening and service conditions. • We model the relationship between the pre-tightening torque and the applied tightening torque. • We verify that the pre-tightening torque is apparently determined by the friction on the contacting interface. [ABSTRACT FROM AUTHOR]

Purpose: This in vitro study aimed to evaluate the effectiveness of a sealing agent in sealing the abutment/implant interface and the preload maintenance of retaining screws after mechanical cycling. Methods: Six groups (n = 12) were evaluated according to the abutment/implant system (external-hexagon implant and UCLA abutments, EHU; Morse taper implant and UCLA abutments, MTU; and Morse taper implant and flexcone abutments, MTF) and the presence of an anaerobic gel sealing agent (control group, no sealing agent; experimental group, sealing agent). Toluidine blue (0.7 μL) was inserted into each implant and the abutments were attached to the implants using a digital torque wrench to evaluate the sealing of the abutment/implant interface. The specimens were tested through mechanical cycling (1 x 106 cycles, 2 Hz, and 130 N). Dye release from the abutment/implant interface was analyzed using a spectrophotometer, and the reverse torque values were obtained using a digital wrench. Reverse torque and dye release data were measured after mechanical cycling and analyzed using ANOVA and Tukey's test (α =.05). Results: All experimental groups showed higher reverse torque values than the control groups (P <.05). In general, the MTU and MTF experimental groups, as well as the MTF control group, showed no significant dye release at different periods (P >.05). Conclusions: The use of a sealing agent improved the preload maintenance of screw-retained implant-supported prostheses. The sealing agent was effective in sealing the Morse taper connection. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the precision of mechanical torque wrenches used for implants in dental offices.Materials and Methods: Mechanical torque wrenches (n = 138) with two functional designs and made by three manufacturers were tested by three groups of investigators. Potential influences on accuracy were tested. Relative deviations from targeted torque values and the precision of recorded torque values were analyzed.Results: Most abutment screws were tightened too tightly rather than too weakly. Differences were apparent in the influence of the functional design of torque wrenches on their precision. No significant correlation between absolute frequency of use and relative deviation or precision was detected. Investigators with different levels of experience exhibited significantly different deviations from targeted torque values.Conclusions: Average deviation from intended torque values, and levels of imprecision, are evidently not major problems in implant prosthetics; however, high torque values are a cause for concern. [ABSTRACT FROM AUTHOR]

Bolted joints are widely used in industrial applications and joint failure can cause a disastrous accident if loosening happens. Bolt loosening detection can be made by regular manual inspection or by using sensors based on different physical principles, such as acoustoelastic effect, piezoelectric active sensing, and electromechanical impedance. Compared with the above methods, vibration based bolt looseness monitoring using accelerometers is appealing for its economy and convenience for measurement. In this paper, cargo bolts looseness monitoring under random excitation is studied based on vibration transmissibility, which overcomes the drawback of commonly used vibration methods in finding local bolt looseness. Vibration transmissibility analysis only uses two vibration transducers to monitor bolt group looseness, where the vibration signal below the cargo bolts is used as the "input" and the other one above the cargo bolts is used as the "output." There are 12 bolts in the cargo bolts studied in this paper, providing an essential clamping force to fix cargo during transportation. Six kinds of bolt group looseness with an increasing degree are simulated in the experiment. The experimental analysis shows that variation of the spectral moment can be used to monitor the global variation of the torque wrench exerted on the cargo bolts. The early stage of the bolt group looseness is that some one or two bolts begin to loose; however, the spectrum moment factor is insensitive to the local bolt looseness in the bolt group. To address this issue, the eigensystem realization algorithm (ERA) based on random input and output is utilized to find the subtle eigenvalue variation of the system matrix, which is neglected by the frequency transmissibility function. The experimental results show the effectiveness of the proposed method for detecting local bolt looseness. [ABSTRACT FROM AUTHOR]

In this paper, we propose a generic method of online motion generation and control that realizes quasi-static multi-contact motion for real position-controlled humanoids. The proposed system calculates command joint angle online by prioritized inverse kinematics that realizes the target contact states and the target position/orientation of interaction end-effectors feasibly. In order to enable control of contact wrench and joint torque with position-controlled robots, Jacobian matrixes (PWT Jacobian matrix) focusing on relationships between command joint angle and actual joint position, contact wrench, and joint torque are introduced. In addition, contact wrench is estimated at the body parts where force sensors are not mounted to enable contacts there, and joint load reduction based on the motor temperature is taken into account to enable long-term motions with real humanoids. The proposed method was verified by a real life-size position-controlled humanoid HRP2-JSKNTS, and various multi-contact motions such as desk climbing using the right knee and both arms were realized. [ABSTRACT FROM AUTHOR]