Mean Torque Research Articles

Experimental investigation on identification of lithologies and layered rock interface based on drilling vibration response

The rapid and accurate acquisition of lithologies and rock interfaces is an important prerequisite for guiding the development of oil gas and solid mineral resources as well as the construction of tunnel engineering. However, few studies have been conducted to identify the lithologies and rock interfaces using drilling information. The author used a drilling test platform and an integrated drilling information acquisition system to conduct drilling vibration tests on rock samples of limestone, sandstone, and coal with different lithologies and rock strengths. The test results indicated the following: 1) The drilling vibration response can characterize the properties of the lithology and rock strength and can be used as a key index to distinguish the lithologies and rock layer interface. 2) There were substantial differences in the drilling response (WOB and torque) and vibration response (vibration velocity, acceleration, and amplitude) of the single rock sample. The mean axial vibration velocities of coal, limestone, and sandstone were 5.6, 7.3, and 13.9 mm/s, respectively. The mean axial vibration accelerations were 9.2g, 32.3g, and 13.1g, respectively. The mean amplitudes of the rock surface were 402.6, 588.3, and 2003.8 μm, respectively. The mean weight on the bit was 1.3, 2.6, and 3.5 kN,1 respectively, and the mean torque was 12.3, 25.1, and 33.6 N m, respectively. 3) For the combined rock samples, the drilling and vibration responses of the layered rock interface showed an evident surge. 4) The rock strength affected the drilling and vibration responses. The stronger the rock, the higher was the drilling response (WOB and torque), higher the vibration acceleration, and lower the vibration speed and amplitude. The drilling vibration response displayed a high sensitivity to rock strength. It could effectively characterize the strength characteristics of the rock to accurately identify the lithologies and layered rock interface.

Influencia del ácido ascórbico en pruebas biomecánicas deimplantes dentales. Estudio experimental en conejos

Objective: To compare, through biomechanical torque tests and resonance frequency analysis, Oxalife surface titanium implants, without and with vitamin C, placed in rabbit femurs.Methods: 17 Tree-Oss Rapid surface Oxalife implants of 7 mm in length and 3.3 mm in diameter with external hexagon connection were used, placed in the femur of 8 hybrid breed rabbits.Following the drilling sequence indicated by the manufacturer. Insertion torque and resonance frequency analysis were recorded to measure the initial stability coefficient. Euthanasia was performed at 60 days; then the implants were exposed to measure the final or biological stability coefficient through resonance frequency analysis (Osstell) and removal torque (Mark-10 Gauge). The data were subjectedto parametric contrast Student test.Results in Ncm: Mean insertion torque value for the experimental group 16.5 ± 3.7 and for the control group 23.3 ± 4.2, with a significant difference (p<0.01). Mean removal torque for the experimental group 69.3 ± 17.4, and control group 87.2 ± 24.9 without significant differences (p=0.14). Average initial ISQ for the experimental group 40.2 ± 7.8 and for the control group 44.7 ± 6.9 (p=0.24). Final ISQ average for the experimental group 50.8 ± 1.1 and for the control 50.5 ± 2.0 (p=0.77) without differences in both measurements.Conclusion: The addition of vitamin C on the surface of the implant would not have a significant effect regarding the stability values during osseointegration

Effects of a Perioperative Blood Flow Restriction Therapy Program on Early Quadriceps Strength and Patient-Reported Outcomes After Anterior Cruciate Ligament Reconstruction.

Quadriceps muscle atrophy remains a limiting factor in returning to activity after anterior cruciate ligament reconstruction (ACLR). Blood flow restriction (BFR) therapy may accelerate quadriceps strengthening in the perioperative period. To evaluate postoperative isometric quadriceps strength in patients who underwent ACLR with a perioperative BFR program. Randomized controlled trial; Level of evidence, 1. Patients indicated for ACLR were randomized into 2 groups, BFR and control, at their initial clinic visit. All patients underwent 2 weeks of prehabilitation preoperatively, with the BFR group performing exercises with a pneumatic cuff set to 80% limb occlusion pressure placed over the proximal thigh. All patients also underwent a standardized postoperative 12-week physical therapy protocol, with the BFR group using pneumatic cuffs during exercise. Quadriceps strength was measured as peak and mean torque during seated leg extension and presented as quadriceps index (percentage vs healthy limb). Patient-reported outcomes (PROs), knee range of motion, and quadriceps circumference were also gathered at 6 weeks, 3 months, and 6 months postoperatively, and adverse effects were recorded. Included were 46 patients, 22 in the BFR group (mean age, 25.4 ± 10.6 years) and 24 in the control group (mean age, 27.5 ± 12.0 years). At 6 weeks postoperatively, the BFR group demonstrated significantly greater strength compared with the controls (quadriceps index: 57% ± 24% vs 40% ± 18%; P = .029), and the BFR group had significantly better Patient-Reported Outcomes Measurement Information System-Physical Function (42.69 ± 5.64 vs 39.20 ± 5.51; P = .001) and International Knee Documentation Committee (58.22 ± 7.64 vs 47.05 ± 13.50; P = .011) scores. At 6 weeks postoperatively, controls demonstrated a significant drop in the peak torque generation of the operative versus nonoperative leg. There were no significant differences in strength or PROs at 3 or 6 months postoperatively. Three patients elected to drop out of the BFR group secondary to cuff intolerance during exercise; otherwise, no other severe adverse events were reported. Integrating BFR into perioperative physical therapy protocols led to improved strength and increased PROs at 6 weeks after ACLR. No differences in strength or PROs were found at 3 and 6 months between the 2 groups. NCT04374968 (ClinicalTrials.gov identifier).

Sex differences in knee extensor torque control.

There is currently equivocal evidence regarding sex-related differences in measures of muscle force and torque control. To that end, we investigated sex differences in knee extensor muscle torque control, using both magnitude- and complexity-based measures, across contraction intensities typical of activities of daily living. 50 participants (25 male, median age [and interquartile range] 23.0 [20.0-33.0]; 25 female, median age [and interquartile range] 21.0 [20.0-40.5]) performed a series of intermittent isometric knee extensor contractions at 10, 20 and 40% maximal voluntary contraction (MVC). Torque was measured in N·m and torque control was quantified according to the magnitude (standard deviation [SD], coefficient of variation [CV]) and complexity (approximate entropy [ApEn], detrended fluctuation analysis [DFA] α) of torque fluctuations. Males exhibited a significantly greater absolute magnitude (i.e., SD) of knee extensor torque fluctuations during contractions at 10% (P=0.011), 20% (P=0.002) and 40% MVC (P=0.003), though no sex differences were evident when fluctuations were normalised to mean torque output (i.e., CV). Males exhibited significantly lower ApEn during contractions at 10% (P=0.002) and 20% MVC (P=0.024) and significantly greater DFA α during contractions at 10% (P=0.003) and 20% MVC (P=0.001). These data suggest sex differences in muscle torque control strategies and highlight the need to consider both the magnitude and complexity of torque fluctuations when examining sex differences in muscle force control.

Local Application of Melatonin on Dental Implant Osseointegration: Analysis of Removal Torque. Experimental Study on Rabbits

Melatonin may interfere with the function of osteoclasts and inhibit bone resorption mainly due to its antioxidant properties and ability to detoxify free radicals. This inhibition can be enhanced by the reaction of indolamine in osseoclastogenesis and may have benefits in implantology. Aims: To evaluate the mechanical and biological behavior of osseointegration using melatonin. To compare the stability coefficient of implants at the time of placement (initial or mechanical ISQ) and after 60 days (final or biological ISQ). To measure the disinsertion torque in both groups of rabbits, with and without melatonin application. Materials and Methods: A total of 16 implants of the same brand and size were placed, with 9 of them receiving 3mg of melatonin powder prior to installation and 7 control implants without melatonin. Resonance frequency analysis (Osstell®) was used to measure initial and biological anchorage, as well as removal torque. Results: The mean removal torque for melatonin-treated implants was 99.8 Ncm, and for control implants, the mean was 87.2 Ncm. The differences between the two groups were not statistically significant. However, there were significant differences in biological ISQ values. Conclusions: The use of melatonin improved the response to osseointegration, particularly in the measurement of final or biological ISQ values.

Effect of tip path overlap on ring debarker performance of frozen and unfrozen black spruce logs

ABSTRACT The effect of the tip path overlap on debarking quality of unfrozen and frozen black spruce logs was studied. The power, energy consumption, and torque were also measured for both temperature conditions. The experiment consisted of debarking logs using three overlaps (8, 27, and 43%) at two temperatures (−12°C and +20°C). Debarking quality was evaluated by the proportion of bark remaining on log surfaces and by the amount of wood in bark residues. Log characteristics (dimensions, eccentricity, and knot features), bark/wood shear strength (BWSS), moisture content, and basic densities of sapwood, inner, and outer barks were measured and treated as covariates. Experiments revealed that tip path overlap affects debarking quality for both temperature conditions: the amount of bark remaining on log surfaces decreased, and the proportion of wood in bark residues increased as tip path overlap increased. In addition, the effects of bark/wood shear strength, the proportion of knot area and sapwood, inner and outer barks densities, and moisture content on debarking quality criteria were analyzed. The mean power, energy consumption, and torque increased as the tip path overlap increased. These parameters were also positively affected by the log diameter and BWSS for frozen logs. The results give helpful information to improve debarking quality within the studied range of overlaps, log characteristics, and debarking parameters with efficient energy use.

Human-Delivered Brushstroke Characterization using an Instrumented Brush Focused on Torque.

Pleasant brush therapies may benefit those with autism, trauma, and anxiety. While studies monitor brushing velocity, hand-delivery of brush strokes introduces variability. Detailed measurements of human-delivered brushing physics may help understand such variability and subsequent impact on receivers' perceived pleasantness. Herein, we instrument a brush with multi-axis force and displacement sensors to measure their physics as 12 participants pleasantly stroke a receiver's forearm. Algorithmic procedures identify skin contact, and define four stages of arrival, stroke, departure, and airtime between strokes. Torque magnitude, rather than force, is evaluated as a metric to minimize inertial noise, as it registers brush bend and orientation. Overall, the results of the naturally delivered brushing experiments indicate force and velocity values in the range of 0.4 N and 3-10 cm/s, in alignment with prior work. However, we observe significant variance between brushers across velocity, force, torque, and brushstroke length. Upon further analysis, torque and force measures are correlated, yet torque provides distinct information from velocity. In evaluating the receiver's response to individual differences between brushers of the preliminary case study, higher pleasantness is tied to lower mean torque, and lower instantaneous variance over the stroke duration. Torque magnitude appears to complement velocity's influence on perceived pleasantness.

Numerical Simulations of the NREL Phase VI Wind Turbine with Low-Amplitude Sinusoidal Pitch

Currently, most wind turbine performance analyses and simulations are performed assuming constant pitch and yaw angles during each rotation. Nevertheless, induced vibration or rotor imbalance can affect the pitch or yaw angle within each rotation. In this study, the effects of low-amplitude sinusoidal pitch angle oscillations of the blade on the performance of a wind turbine was investigated numerically by comparing it against the baseline (without pitch variations). Large eddy simulations were performed in which the motion of blades was handled by the curvilinear immersed boundary (CURVIB) method. The grid resolution was increased near the moving immersed boundaries using dynamic overset grids to resolve rotating blades. It was found that low-amplitude (up to 3 degrees) sinusoidal oscillations in the pitch angle negligibly affected the mean torque but increased its fluctuations and created distinct features in the wake of the turbine. In fact, the turbine’s mean torque at wind speed of 15 m/s decreases from 1245 N.m to 1223 N.m, while its fluctuation (standard deviation) increases from 2.85 N.m to 7.94 N.m, with a dynamic pitch of 0.5 degrees and frequency of 3.6 Hz.

Analysis of Electromagnetic Parameters of Hybrid Externally Excited Synchronous Motors for Electric Vehicle Applications

This paper presents two different approaches to improve the electromagnetic torque and output power of the hybrid Externally Excited Synchronous Motor (EESM) applied to Electric Vehicles (EVs). An analytical approach is first considered to define the main parameters of the proposed machine. Based on the obtained results from the analytical model, the hybrid EESM is designed with different rotor shapes and step-skewing magnet segments to reduce the total losses and improve torque ripple. Then, Finite Element Analysis (FEA) is applied to compute and simulate electromagnetic parameters, such as the magnetic flux density, mean torque, and output power. The development of these two approaches is validated on an actual EESM machine and the agreement with the theory is shown.

Impact of Rotor Flux-Barriers on Coupling Coefficient in a Brushless Doubly-Fed Reluctance Machine

A brushless doubly-fed reluctance machine offers several advantages over a single-port machine since it requires a partially-rated power converter, provides reduced maintenance, and operates without permanent magnets. The complexity of the air-gap magnetic fields due to differing winding-pole numbers interacting with a reluctance rotor have precluded the use of an analytical framework to optimize the rotor. Instead, researchers have relied upon time-consuming finite element analysis (FEA). This paper presents an analytical method to compute closed-form solutions for the mean torque, captured by the coupling coefficient, using a practical circular ducted rotor. The method also accounts for the potential drop across the flux-barriers, leading to a better estimation of mean torque. The model is validated using both FEA and experimental tests.

A Comparison of Abutment Screw Loosening in 24-Degree Angulation-Correcting and Straight Implants: An In Vitro Study.

To compare abutment screw loosening in 24-degree angulation-correcting and straight implants subjected to nonaxial cyclic loading. Seven external connection 24-degree angulation-correcting implants (AI) and seven external connection straight implants (SI) were embedded in acrylic resin within a brass housing. A hemispherical titanium fatigue abutment was secured to each implant using a titanium abutment screw tightened to 32 Ncm. Each implant-abutment complex was positioned within a tooth wear machine and subjected to 1,000,000 cycles of 50-Ncm nonaxial loading to simulate 1 year of function. The abutment screw removal torque values were measured before and after cyclic loading, and the differences were statistically analyzed using two-way ANOVA and post hoc pairwise Dunn tests. Scanning electron microscopy and finite element analyses were performed to assess the wear of the abutment screws. The mean torque loss for the AI group was 21.44% (P < .001) compared to 24.56% (P < .001) for the SI group. There was a statistically significant difference between the AI and SI groups (P &#61; .006). Both groups exhibited significant abutment screw loosening. Within the limitations of this study, 24-degree angulation-correcting implants resisted screw loosening significantly more than straight implants.

Two‐phase switched reluctance motor with hybrid excitation: Modeling and evaluation

AbstractSwitched reluctance machines offer a robust structure, inexpensive maintenance, and a low‐cost drive. However, they can suffer from low mean torque, low torque density, and high noise. Techniques such as offering the stator poles at each phase in the shape of a C core, adding several teeth to the two poles of each C‐core, and embedding permanent magnets to overcome these deficiencies are presented. Permanent magnets are embedded into the structure to create a hybrid excitation that provides a higher torque density. The C‐core stator modules of the stator are toothed to improve the torque. The radial forces on the shaft are balanced. The design procedure, operating principles, and performance trade‐offs are explained. Also, a magnetic equivalent circuit model is introduced. The model provides continuous relationships over the operating regions and incorporates core saturation and accurate flux tubes to attain high precision. Finite element models are also employed in the analysis and design process. The motor is prototyped, and experimental results are extracted, closely matching those obtained with the model and finite‐element analysis.

Biomechanical comparison of intramedullary nail and plate osteosynthesis for extra-articular proximal tibial fractures with segmental bone defect.

Purpose: Proximal tibial fractures are common, but the current available internal fixation strategies remain debatable, especially for comminuted fractures. This study aimed to compare the biomechanical stability of three internal fixation strategies for extra-articular comminuted proximal tibial fractures. Methods: A total of 90 synthetic tibiae models of simulated proximal tibial fractures with segmental bone defects were randomly divided into three groups: Single lateral plating (LP), double plating (DP) and intramedullary nailing (IN). Based on the different number of fixed screws, the above three groups were further divided into nine subgroups and subjected to axial compression, cyclic loading and static torsional testing. Results: The subgroup of intramedullary nailing with five proximal interlocking screws showed the highest axial stiffness of 384.36 ± 35.00N/mm. The LP group obtained the lowest axial stiffness performance with a value of 96.59 ± 16.14N/mm. As expected, the DP group offered significantly greater biomechanical stability than the LP group, with mean static axial stiffness and mean torque increasing by approximately 200% and 50%, respectively. According to static torsional experiments, the maximum torque of the DP subgroup was 3,308.32 ± 286.21N mm, which outperformed all other groups in terms of torsional characteristics. Conclusion: Utilizing more than four distal screws did not provide improved biomechanical stability in the LP or DP groups, while a substantial increase in the biomechanical stability of DP was obtained when an additional medial plate was used. For the intramedullary nailing group, increasing the number of proximal interlocking screws could significantly improve biomechanical stability, and the intramedullary nailing with three proximal interlocking screws had similar static and cyclic stiffness as the DP group. The intramedullary nailing with five proximal screws had better axial stability, whereas DP had better torsional stability.

Modelling methods and structure topology of the switched reluctance synchronous motor type machine: a review

The switched reluctance synchronous motors (SRSM) have been utilised as replacements for induction motors (IM) and permanent magnet synchronous motors (PMSM). The SRSM is a feasible solution for electric motors because of its robust and straightforward structure, resulting in low maintenance, manufacturing, and operating costs. However, the SRSM has several flaws, including low mean torque, low torque density and excessive torque ripples. The SRSM performance can be improved by considering the structure topology and driving system. This paper reviewed the performance characteristic of SRSM based on the structural topology. Several literature studies on the segmented structure topologies of SRSM were compared with the conventional structures. The performance of the SRSM can be estimated by using either numerical or analytical methods. The FEA and BEM are numerical techniques extensively used to optimise electrical motor performance. Although the numerical method can accurately estimate motor performance, the significant drawback is quite complicated, time-consuming, and difficult to implement the control algorithm with FEA software. However, the analytical method, especially the MEC method, is faster in evaluating motor performance and significantly reduces computational complexity, either with or without solving high-dimensional system matrices.

The Role of Contraction Mode in Determining Exercise Tolerance, Torque-Duration Relationship, and Neuromuscular Fatigue.

Critical torque (CT) and work done above it ( W ') are key predictors of exercise performance associated with neuromuscular fatigue. The aim of the present study was to understand the role of the metabolic cost of exercise in determining exercise tolerance, CT and W ', and the mechanisms of neuromuscular fatigue. Twelve subjects performed four knee extension time trials (6, 8, 10, and 12 min) using eccentric, isometric, or concentric contractions (3-s on/2-s off at 90°·s -1 or 30°·s -1 ) to modulate the metabolic cost of exercise. Exercise performance was quantified by total impulse and mean torque. Critical torque and W ' were determined using the linear relationship between total impulse and contraction time. Cardiometabolic, neuromuscular, and ventilatory responses were quantified. Neuromuscular function was evaluated by maximal voluntary contraction, resting potentiated single/doublet electrical stimulations, and superimposed single electrical stimulation to quantify neuromuscular, peripheral, and central fatigue, respectively. Compared with isometric exercise, total impulse (+36% ± 21%; P < 0.001), CT (+27% ± 30%; P < 0.001), and W ' (+67% ± 99%; P < 0.001) were increased during eccentric exercise, whereas total impulse (-25% ± 7%; P < 0.001), critical torque (-26% ± 15%; P < 0.001), and W ' (-18% ± 19%; P < 0.001) were reduced in concentric exercise. Conversely, the metabolic response and the degree of peripheral fatigue were reduced during eccentric exercise, whereas they were increased during concentric exercise. Critical torque was negatively associated with oxygen consumption gain ( R2 = 0.636; P < 0.001), and W ' was negatively associated with rates of neuromuscular and peripheral fatigue indices ( R2 = 0.252-0.880; P < 0.001). The contraction mode influenced both CT and W ', and consequently exercise tolerance, indicating that the metabolic cost of contraction played a key role.

Study on Stator-Rotor Misalignment in Modular Permanent Magnet Synchronous Machines with Different Slot/Pole Combinations

Addressing stator-rotor misalignment, usually called eccentricity, is critical in permanent magnet (PM) machines since significantly high radial forces can be developed on the bearings, which can trigger a major fault and compromise the structural integrity of the machine. In this regard, this paper aims to provide insight into the unaddressed identification and analysis of the impact of eccentric tolerances on relevant performance indices of permanent magnet synchronous machines (PMSMs) with modular stator core. Static and dynamic eccentricity are assessed for different slot/pole combinations through the finite element method (FEM), and the results are compared with those of PMSMs with a conventional stator core. The unbalanced magnetic forces (UMF), cogging torque, back-emf, and mean torque variations are described and related to the eccentricity magnitude and classification. The main findings indicate that severe radial forces and significant additional cogging torque harmonics are generated because of eccentricity. Additionally, it is found that the main differences between modular PMSMs and conventional PMSMs rely on the value of slots per pole per phase.

A look-up table-based model predictive torque control of IPMSM drives with duty cycle optimization

Model Predictive Control (MPC) is an effective method of driving motors and power converters due to its quick response, integrity, and multivariable control adaptability. A model-predictive torque control (MPTC) technique for permanent magnet synchronous motors (IPMSMs), which is computationally efficient and of low complexity, is presented in this paper. The proposed technique designs a lookup table that is independent of flux angle and torque deviation. For each control instant, this technique has to evaluate four voltage space vectors (VSV) from the lookup table, resulting in a substantial reduction in switching frequency and computational burden without compromising the performance. A maximum torque per ampere (MTPA) technique generates reference currents. The controller’s complexity is minimized by eliminating the flux weighting factor from the cost function, saving time on offline weighting factor adjustments. Moreover, duty cycle optimization is performed using the mean torque control technique to minimize torque and flux ripples. The proposed method has been experimentally validated using a real-time simulator hardware in loop (HIL) with a TMS320F28335 floating-point digital signal processor on a prototype IPMSM drive. Furthermore, the proposed MPTC scheme is compared to conventional MPTC and direct torque control (DTC).

Difference in Joint Stability Between Small Posterior Malleolar Fragments With Fixation and Those Without Fixation: A Biomechanical Cadaver Study

The indication for the surgical treatment of ankle fractures that involve a posterior malleolar fragment remains controversial. This cadaver study assessed the biomechanical results of rotation stiffness of Haraguchi type 1 posterior malleolar fragments with or without cannulated screw fixation. Twelve anatomic lower-extremity specimens from 6 cadavers were tested. Six right legs were subjected to posterior malleolus osteotomy (Haraguchi type I) followed with (group A; n=3) or without (group B; n=3) fixation using a cannulated screw. Ankle joint stability was measured under both external rotation force and axial loading, and the passive resistive torque was measured in both groups. The mean torque value in group A was 0.1093 Nm/º, while that in group B was 0.0537 Nm/º. There was a significant intergroup difference (p=.004). In group B, the torque value was further increased in the latter rotation period (about 40-60 degrees). Group A proved more stable under experimental conditions than group B. Fixation in type I posterior malleolar fragments produced improved stability in ankle rotation, even for posterior malleolar fragments involving <25% of the articular surface, and has been considered an effective aid in treatment.

Cholesterol promotes similar chain packing in n-3 PUFA-containing membranes.

Cholesterol's organization in biomembranes has great influence on membrane function. Omega-3 polyunsaturated fatty acid (n-3 PUFA)-containing lipids are believed to have a myriad of health benefits and are known to modulate membrane organization in model membranes via their aversion for cholesterol. 2H NMR has observed that different n-3 PUFA-containing phosphatidylcholine (PC) lipids modulate membrane organization to different degrees. In ternary lipid mixtures with sphingomyelin and cholesterol, docosahexaenoic acid (DHA, 22:6)-containing PC infiltrates lipid rafts more than eicosapentaenoic acid (EPA, 20:5)-containing PC. Additionally, molecular dynamics (MD) simulations have shown that n-3 PUFA-containing membranes differ in their stereospecific interactions with cholesterol. The mean-torque model provides a method of relating lipid disorder to a thermodynamic parameter (potential of mean torque) which can be used to quantify lipid-lipid interactions. Here we apply this approach to compare 1-stearoyl-2-eicosapentaenoylphosphatylcholine (EPA-PC, 18:0-20:5PC), 1-stearoyl-2-docosahexaenoylphosphatylcholine (DHA-PC, 18:0-22:6PC), 1-stearoyl-2-docosapentaenoylphosphatylcholine (DPA-PC, 18:0-22:5PC) and, as a monounsaturated control, 1-stearoyl-2-oleoylphosphatidylcholine (OA-PC, 18:0-18:1PC) bilayers and their interactions with cholesterol. Analysis of data from 2H NMR and MD simulations shows that all three n-3 PUFA-containing phospholipids display similar chain packing in the presence of cholesterol, which is illustrated by the projected chain length of the sn-1 chains.

A Digital 3D Retrospective Study Evaluating the Efficacy of Root Control during Orthodontic Treatment with Clear Aligners

This study aimed to investigate the efficacy of torque movement and the incidence of root resorption in the maxillary and mandibular teeth with clear aligner therapy using cone-beam computed tomography. The sagittal root positions, the faciolingual inclinations, and the root lengths of 672 teeth, from central incisors to first molars for each arch, were measured and compared on virtual cross sections from pre-treatment and post-treatment cone-beam computed tomography of 28 patients who received comprehensive orthodontic treatment with clear aligners. An improvement of root position was found in incisors, canines, and premolars of the upper and lower arches: over 78% of their root was centered in the alveolus at the end of orthodontic treatment. There was a statistically significant torque increase for incisors, canines, and first premolars at the end of therapy. The most considerable torque changes were achieved in incisors and canines, while the lowest was in posterior teeth. The maxillary and mandibular central incisors achieved 3.26 ± 1.95° and 2.97 ± 2.53° of mean torque increase, respectively. The root length loss was greater in the upper and lower central incisors. All teeth showed mild resorption (&lt;10%) except for two upper lateral incisors, which showed moderate resorption (10.79% and 10.23%). Comprehensive treatment with clear aligners improved sagittal root position and increased torque, especially in the anterior teeth. Most teeth showed mild resorption after clear aligner therapy, and only two showed moderate resorption.