Drilling Procedure Research Articles

Modelling and simulations for signal loss evaluation during sampling phase for thermoluminescence authenticity tests

<p class="Abstract"><span lang="EN-GB">In authenticity tests using the thermoluminescence (TL) method, the sampling phase is fundamental to collecting an appropriate amount of powder for analysis. The powder is usually obtained by drilling in hidden and pertinently selected areas of an artefact. During the drilling, a local temperature increase can occur, and, because thermoluminescence emission is dependent on the heating rate, the authenticity test result could be invalidated due to underestimation of the signal intensity. In this work, the percentage of signal intensity loss is investigated through the combination of a dynamic electro-mechanical model and a typical TL glow curve simulation. After first modelling the drilling procedure to estimate the maximum temperature reached, the optimal parameters that should be used during the sampling phase are checked by simulations together with an evaluation of the correlated signal losses.</span></p>

“Effect of low friction chromium surface coating of drills on heat generation during simulated implant osteotomy preparation: an in vitro study”

Brief Background To evaluate the effect of low friction chromium surface coating of drills on heat generation during implant osteotomy preparation in standardized simulated bone blocks. Materials and Methods 32 Artificial polyurethane bone blocks were used as the study models. 32 twisted stainless-steel design drills of three different sizes 2.0mm, 2.4mm and 2.8mm x 18mm were used. Drills were divided into two groups as control (Group 1) and low friction chromium coated (Group 2) drills. Surface coatings of drills were made for Group 2 drills with Low friction chromium. Standardized drilling protocol was used to avoid influence of other drilling factors on heat generation. Osteotomies were performed and temperatures were recorded during drilling procedure using thermocouples at different depths of 4mm, 8mm and 12mm. Method In this study, it was observed that the temperature changes in the thermocouples reading were significant (p<0.001) when compared with control and test group drills, proving that LFC coated drills reduced the heat generated during implant osteotomy preparation due to reduction in frictional contact between the drills and bone. Also, the temperature changes recorded at different depths of drill site showed an increase in temperature with increase in depth of drill site but the values were not statistically significant (p>0.5) to prove the result. Summary and Conclusions Drill depth did not have a significant (p>0.5) effect on heat generation during implant osteotomy preparation. Low friction chromium surface coating can reduce heat generated during implant osteotomy preparation by reducing the frictional contact between the bone and the drill surface. Key Words: dental implants; low friction; heat; polyurethane

Design and Analysis of a While-Drilling Energy-Harvesting Device Based on Piezoelectric Effect

A while-drilling energy harvesting device is designed in this paper to recovery energy along with the longitudinal vibration of the drill pipes, aiming to serve as a continuous power supply for downhole instruments during the drilling procedure. Radial size of the energy harvesting device is determined through the drilling engineering field experience and geological survey reports. A piezoelectric coupling model based on the selected piezoelectric material was established via COMSOL Multiphysics numerical simulation. The forced vibration was analyzed to determine the piezoelectric patch length range and their best installation positions. Modal analysis and frequency response research indicate that the natural frequency of the piezoelectric cantilever beam increased monotonously with the increase of the piezoelectric patch’ thickness before reaching an inflection point. Moreover, the simulation results imply that the peak voltage of the harvested energy varied in a regional manner with the increase of the piezoelectric patches. When the thickness of the piezoelectric patches was 1.2–1.4 mm, the designed device gained the best energy harvest performance with a peak voltage of 15–40 V. Works in this paper provide theoretical support and design reference for the application of the piezoelectric material in the drilling field.

Influence of different drilling methods on the behavior of post‐installed mechanical fasteners in uncracked and cracked concrete

AbstractInnovative drilling methods gain importance in the field of post‐installed fasteners. For this reason, users, customers and manufacturers demand methods other than the standard drilling procedure of hammer drilling, as they are hollow drilling with included cleaning and diamond drilling without emitting drill dust. One open question regarding these drilling methods is the equivalence of the behavior under the conditions of cracked concrete over the entire lifetime. These conditions are typically tested in the crack movement test, which simulates the real behavior of a fastener in cracked concrete over a designed lifetime of 50 years. In this contribution, the example of a post‐installed mechanical bolt anchor is used to explain how a difference in the behavior is a consequence of different drilling methods in noncracked concrete, in cracked concrete and in cracked concrete in which the crack is cycled. Additionally, it is observed that the behavior in the crack cycling test is significantly influenced by the drilling method.

Survey of Mental Health of Dentists in the COVID-19 Pandemic in the UK.

ABSTRACTAim:To assess the impact of work-related changes on the mental health (MH) of dentists during the peak of COVID-19 pandemic in the UK.Materials and Methods:Dentists involved in certain treatments, for example, high-speed drilling procedures, generate infectious aerosols. These Aerosol Generating Procedures (AGPs) are at the highest risk of transmission of coronavirus. During the COVID-19 pandemic, a significant number of dentists in the UK were restricted from providing treatments to reduce the risk of viral transmission. Some of the dentists providing urgent dental treatment were involved in AGPs. Significant and sudden changes in the delivery of dental care in the current pandemic may have impacted the MH of dentists. An online survey was conducted, using validated tools to measure the MH symptoms and stress. Pearson's chi-squared test of independence was used for statistical analysis.Results:Overall, 123 dentists participated in the survey. The prevalence of anxiety-related symptoms was 71% (95% CI 0.62–0.78), depression-related symptoms was 60% (95% CI 0.51–0.68), and stress was 92% (95% CI 0.86–0.96). Dentists working in the independent sector had more psychological symptoms compared with those in the public sector (P = 0.014).Conclusions:Working in the public sector appeared to have a protective effect. Almost all the dentists in this survey were experiencing MH symptoms and stress. Further research is needed to assess the long-term effect of the COVID-19 pandemic on dentists.

Surface quality and pullout strength of ultrasonically-assisted drilling cortical bone.

Bone surgery is a complex process involving sustainable and healthy human recuperation, but poor surface quality and loose implant fixtures can affect the recovery time of orthopedic patients. However, it has been demonstrated that the application of ultrasonic vibration during drilling procedures can improve the success of bone remediation procedures. The focus of the present paper was on the investigation of surface quality and pullout strength of drilled holes. After analyzing the special kinematic characteristics of the ultrasonically-assisted drilling (UAD), UAD testing using fresh cortical bone was carried out and compared with the results obtained after conventional drilling (CD) procedures. Surface roughness measurements and microscope examination were used to evaluate surface quality, and an electro-mechanical tensile machine was used to measure pullout resistance. The test findings indicated that surface roughness was reduced by 17-68.7% when using UAD; the axial pullout strength of screws inserted into UAD holes was significantly increased by 4.28-30.1% compared to that of CD. It was found also that low spindle speeds and high feed rates reduced surface quality and the stability of the inserted cortical screws. The findings demonstrated that UAD produced better surface quality and higher pullout strengths, which could provide greater stability for implants and improved post-operative recovery.

Development of Laser Drilling Strategy for Thick Carbon Fibre Reinforced Polymer Composites (CFRP).

Composites from carbon fibre reinforced polymers (CFRPs) play a significant role in modern manufacturing. They are typically used in aerospace and other industries that require high strength-to-weight ratios. Composite machining, however, remains a challenging job and sometimes is hampered by poor efficiency. Despite considerable research being conducted over the past few years on the machining of composite materials, the material nevertheless suffers from delamination, fibre loss, and imperfect finishing of the fuselage. Laser technology is becoming increasingly popular as an alternative approach to cutting and drilling composites. Experiments have been conducted with a CFRP thickness of 25.4 mm using fibre laser to test the effect of the machining parameters on the primary performance measurements. In this study, different machining criteria are used to assess the fibre laser ability of thick CFRP composites for drilling operation. The experimental findings revealed that a fibre laser is capable of penetrating a thick CFRP to a depth of 22 mm by using a novel drilling procedure.

Airborne Aerosolized Mouse Cytomegalovirus From Common Otolaryngology Procedures: Implications for COVID-19 Infection.

ObjectivesTo determine whether common otolaryngology procedures generate viable aerosolized virus through a murine cytomegalovirus (mCMV) model for infection.Study DesignmCMV model of infection.SettingUniversity of Utah laboratory.MethodsThree-day-old BALB/c mice were inoculated with mCMV or saline. Five days later, each mouse underwent drilling, microdebrider, coblation, and electrocautery procedures. Particle size distribution and PM2.5 (particulate matter <2.5 µm) concentration were determined with a scanning mobility particle sizer and an aerosol particle sizer in the range of 15 nm to 32 µm. Aerosolized samples from these procedures were collected with an Aerosol Devices BioSpot sampler for viral titer based on polymerase chain reaction and for viable virus through viral culture.ResultsAs compared with the background aerosol concentrations, coblation and electrocautery showed statistically significant increases in airborne aerosols (Tukey-adjusted P value <.040), while microdebrider and drilling at 30,000 rpm did not (.870 < Tukey-adjusted P value < .930). We identified viral DNA in samples from coblation and drilling procedures, although we did not identify viable viruses in aerosol samples from any of the 4 procedures.ConclusionCoblation and electrocautery procedures generate >100-fold increases in aerosol concentrations over background; only coblation and drilling produce aerosolized viral DNA. The high concentration of aerosols from coblation and electrocautery suggests the need for appropriate safeguards against particle exposure to health care workers. The presence of viral DNA from drilling and coblation procedures warrants the need for appropriate protection against droplet and aerosol exposure.

Advances in analysis of total uncertainties in a semi‐invasive residual stress measurement method

AbstractThe ability to characterise residual stress distribution accurately and over different length scales, particularly deep into an engineering part, plays a significant role in assessing structural integrity. Two most commonly used techniques to measure residual stress fields deep into engineering components include neutron diffraction (ND) and deep‐hole drilling (DHD). As the measurements depend on several physical quantities, they are susceptible to error. The error or uncertainties may turn substantial and compromise the suitability of the results. Although noninvasive, the neutron diffraction technique is neither readily available nor portable and is limited to approximately 60‐mm‐thick specimen; errors associated with results become unacceptable at greater flight paths. Moreover, a mock‐up representing the engineering component is normally used in the ND technique. In contrast, the DHD technique is portable and measures residual stresses with high spatial resolution. An error propagation technique was applied to develop an error analysis procedure taking into consideration various stages of the DHD method and successfully applied to different DHD measurements. An essential feature comprising the effect of plasticity due to the creation of reference hole in the DHD procedure has not yet been taken into account in the error analysis procedure. This paper briefly describes how the uncertainties due to the creation of the initial reference hole can be determined. The effect of plasticity in the drilling procedure is quantified in this study. This error is combined with other sources of error and formulated to determine the total error. An incremental DHD technique was used to measure the complex triaxial residual stress field in an as‐welded circular disc, and the measured data were used to illustrate the total error using the error analysis method developed in the study.

Integration of Formation Evaluation Data Overcomes Offshore Coring Challenges

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 195866, “Overcoming Coring Challenges in a New Unconventional Play Offshore by Integration of Formation Evaluation Data,” by Thomas Bradley, SPE, Baker Hughes, and Per Henrik Fjeld and Jonathan Scott, Aker BP, et al., prepared for the 2019 SPE Annual Technical Conference and Exhibition, Calgary, 30 September-2 October. The paper has not been peer reviewed. A well was drilled into a prospective unconventional mudstone play offshore Norway. Two of five coring runs were successful while the rest yielded little to no core recovery. Subsequent investigation of the core substantiated that the coring issues largely had natural causes. This understanding is being applied to two imminent coring operations and has driven selection of drilling, coring, and wireline technology and procedures and is informing casing design. Introduction The Valhall field is in Block 2/8 of the Norwegian North Sea. The primary reservoir is Cretaceous chalk, located at approximately 2400 m true vertical depth. Production of this reservoir began in 1982. Above this reservoir are other formations, including a shallower potential unconventional mudstone reservoir. A production well was drilled targeting the Cretaceous chalk reservoir. As part of the drilling program, logging-while-drilling (LWD) and wireline logs - including LWD density, neutron, gamma ray and acoustic, wireline spectral gamma ray, cross-dipole acoustic, nuclear-magnetic-resonance, and formation-testing and -sampling - were run across the potential mudstone reservoir to appraise the standard petrophysical properties. A conventional core was also attempted; however, recovery was poor, with repeated jams. Coring Challenges During coring operations, significant problems were encountered when coring the mudstone intervals. These challenges are illustrated in Fig. 1, which shows a section of the core from xx14 m, demonstrating the typical condition of the recovered core when still in the core barrel. At the time of operation, poor recovery was attributed to the coring practices used and no further coring was attempted. Formation Evaluation The mudstone interval was not a primary target for the well. Therefore, limited formation evaluation of these intervals was performed, mainly to estimate the petrophysical properties. However, at the time of initial logging, more-advanced formation evaluation data (e.g., images, full waveform acoustic, and nuclear-magnetic-resonance data) were not evaluated fully. A few years after initial operations, the log data were revisited - specifically, detailed interpretation was conducted for all recorded log measurements. On examination of the results over much of the interval, the integration of the conventional and advanced volumetric measurements gave considerable extra value in assessing the petrophysical properties of the mudstone. However, detailed discussion of these results is outside the scope of this paper. In addition to the extra information gleaned from the advanced volumetric interpretation, over certain intervals, some unusual log responses and interpretation results were seen that were deemed worthy of further investigation.

Model-Based Compensation of Moving Tissue for State Recognition in Robotic-Assisted Pedicle Drilling

Drilling is one of the hardest parts of pedicle screw fixation, and it is one of the most dangerous operations because inaccurate screw placement would injury vital tissues, particularly when the vertebra is not stationary. Here we demonstrate the drilling state recognition method for moving tissue by compensating the displacement based on a simplified motion predication model of a vertebra with respect to the tidal volume. To adapt it to different patients, the prediction model was built based on the physiological data recorded from subjects themselves. In addition, the spindle speed of the drilling tool was investigated to find a suitable speed for the robotic-assisted system. To ensure patient safety, a monitoring system was built based on the thrusting force and tracked position information. Finally, experiments were carried out on a fresh porcine lamellar bone fixed on a 3-PRS parallel robot used to simulate the vertebra displacement. The success rate of the robotic-assisted drilling procedure reached 95% when the moving bone was compensated.

Letter to the Editor Regarding “Twist Drill Procedure for Chronic Subdural Hematoma Evacuation—An Analysis of Predictors for Treatment Success”

Letter to the Editor Regarding “Twist Drill Procedure for Chronic Subdural Hematoma Evacuation—An Analysis of Predictors for Treatment Success”

Personal protective equipment during the coronavirus disease (COVID) 2019 pandemic - a narrative review.

Personal protective equipment has become an important and emotive subject during the current coronavirus disease 2019 epidemic. Coronavirus disease 2019 is predominantly caused by contact or droplet transmission attributed to relatively large respiratory particles which are subject to gravitational forces and travel only approximately 1 metre from the patient. Airborne transmission may occur if patient respiratory activity or medical procedures generate respiratory aerosols. These aerosols contain particles that may travel much longer distances and remain airborne longer, but their infective potential is uncertain. Contact, droplet and airborne transmission are each relevant during airway manoeuvres in infected patients, particularly during tracheal intubation. Personal protective equipment is an important component, but only one part, of a system protecting staff and other patients from coronavirus disease 2019 cross-infection. Appropriate use significantly reduces risk of viral transmission. Personal protective equipment should logically be matched to the potential mode of viral transmission occurring during patient care - contact, droplet or airborne. Recommendations from international organisations are broadly consistent, but equipment use is not. Only airborne precautions include a fitted high-filtration mask, and this should be reserved for aerosol generating procedures. Uncertainty remains around certain details of personal protective equipment including use of hoods, mask type and the potential for re-use of equipment.

Backtalk: Ensuring school safety drills meet ethical standards

Schools have adopted a wide variety of procedures for their safety drills, some of them potentially traumatizing without being effective. David P. Perrodin urges school leaders to look to the world of human research for a model of how to ensure their safety drills are helpful and not harmful. An institutional review board made up of educators, emergency managers, parents, students, and other stakeholders could review any proposed safety drill procedures to ensure they are likely to achieve their purpose without inflicting unnecessary trauma.

Haptic Rendering of Diverse Tool-Tissue Contact Constraints During Dental Implantation Procedures.

Motor skill learning of dental implantation surgery is difficult for novices because it involves fine manipulation of different dental tools to fulfill a strictly pre-defined procedure. Haptics-enabled virtual reality training systems provide a promising tool for surgical skill learning. In this paper, we introduce a haptic rendering algorithm for simulating diverse tool-tissue contact constraints during dental implantation. Motion forms of an implant tool can be summarized as the high degree of freedom (H-DoF) motion and the low degree of freedom (L-DoF) motion. During the H-DoF state, the tool can move freely on bone surface and in free space with 6 DoF. While during the L-DoF state, the motion degrees are restrained due to the constraints imposed by the implant bed. We propose a state switching framework to simplify the simulation workload by rendering the H-DoF motion state and the L-DoF motion state separately, and seamless switch between the two states by defining an implant criteria as the switching judgment. We also propose the virtual constraint method to render the L-DoF motion, which are different from ordinary drilling procedures as the tools should obey different axial constraint forms including sliding, drilling, screwing and perforating. The virtual constraint method shows efficiency and accuracy in adapting to different kinds of constraint forms, and consists of three core steps, including defining the movement axis, projecting the configuration difference, and deriving the movement control ratio. The H-DoF motion on bone surface and in free space is simulated through the previously proposed virtual coupling method. Experimental results illustrated that the proposed method could simulate the 16 different phases of the complete implant procedures of the Straumann® Bone Level(BL) Implants Φ4.8–L12 mm. According to the output force curve, different contact constraints could be rendered with steady and continuous output force during the operation procedures.

Parametric Power Spectral Density Estimation-Based Breakthrough Detection for Orthopedic Bone Drilling with Acoustic Emission Signal Analysis

Manual bone drilling in orthopedic surgical operations may cause injury to patient tissues if the drill bit continues to progress after exiting the bone. In this study, a new bone breakthrough detection algorithm based on acoustic emission (AE) signal analysis has been developed to minimize temporary and permanent injuries that can be caused by surgeon-controlled surgical drills. Three parametric estimation methods, Burg, Yule–Walker and Modified Covariance were used to estimate Power Spectral Density (PSD) of the AE signal during the drilling operation. Four frequency features, Mean Frequency, Median Frequency, Mean–Median and Power Bandwidth were calculated for each PSD estimate. An artificial neural network-based breakthrough detection classification was constructed from the extracted features. The highest breakthrough detection performance was obtained with the features extracted by the Burg method with an accuracy rate of 90.95 ± 0.97% in the training phase and 92.37 ± 1.09% in the test phase. In the detection of Not-Breakthrough situations, the highest accuracy was obtained with features extracted with the Covariance method as 99.04 ± 0.03% in the training phase and 99.05 ± 0.08% in the testing phase. This new approach which could be integrated into conventional drills with minimum configuration changes and without any major cost has the potential to increase the performance and safety of bone drilling procedures.

Fully Automatic Robot-Assisted Surgery for Mandibular Angle Split Osteotomy.

With the development of computer-assisted surgery, preoperational design is detailed in software. However, it is still a challenge for surgeons to realize the surgical plan in the craniofacial surgery. Robot-assisted surgery has advantages of high accuracy and stability. It is suitable for the high-stress procedures like drilling, milling, and cutting. This study aims to verify the feasibility for automatic drilling without soft tissues in model test based on an industrial robot platform.This study chose the data from digital laboratory in Shanghai 9th People's Hospital. The mandibular was reconstructed in software and surgical plan was also designed. Then, the coordinate data was input to the robot's software and matrix conversion was calculated by 4 marked points. The trajectory generation was calculated by inverse kinematics for target coordinates and robot coordinates. The model was fixed and calibrated for automatic drilling. At last, the accuracy was calculated by optic scanning instrument.The installment and preparation cost 10 minutes, the drilling procedure cost 12 minutes. The outside position error was (1.71 ± 0.16) mm, the inside position error was (1.37 ± 0.28) mm, the orientation error was (3.04 ± 1.02)°. Additionally, a total of 5 beagles were tested, with an accuracy error of (2.78 ± 1.52) mm. No postoperative complications occurred.This is the first study reported for robot-assisted automatic surgery in craniofacial surgery. The result shows it is possible to realize the automatic drilling procedure under the condition of no interference like soft tissues. With the development of artificial intelligence and machine vision, robot-assisted surgery may help surgeons to fulfill more automatic procedures for craniofacial surgery.

Suprapectoral biceps tenodesis with bicortical drilling procedures: anatomic analysis of chondral and axillary nerve risk with transhumeral pin guide

Many biceps tenodesis (BT) procedures are described for treating proximal biceps pathology. Axillary nerve injury has been reported during BT using bicortical drilling techniques with variable results depending on the location. In addition, there is a risk of potential articular damage during suprapectoral BT. We sought to determine the distance between the axillary nerve and the posterior passage of a bicortical pin, as well as the risk of articular damage, and to analyze whether a lateral inclination of the pin could avoid the chondral risk during suprapectoral BT with bicortical drilling. Ten cadaveric shoulders were divided into 2 groups. In the first group, we determined the axillary nerve distance from the posterior exit point of 3 pins in a suprapectoral position 15 mm distal to the humeral cartilage: perpendicular, 10° caudal, and 20° caudal inclination. We measured 2 distances from the pin: to the axillary nerve and to the cartilage border. In the second group, we set one pin at the same perpendicular position and set the second pin 15° laterally tilted to determine its extra-articular passage. No pin injured the nerve, whereas all pins showed a transchondral direction. The 20° caudal inclination was the nearest to the nerve (18.8 mm [95% confidence interval, 5.5-32 mm]), but the perpendicular position was the safer position (38.8 mm [95% confidence interval, 28-49.6 mm]). Tilting the pin direction 15° laterally prevented cartilage damage (P = .008). Suprapectoral BT with bicortical drilling performed 15 mm distal to the humeral cartilage is a safe procedure regarding the axillary nerve. A potential humeral chondral injury could be prevented with 15° of lateral inclination of the pin guide.

Stiffness properties analysis and enhancement in robotic drilling application

Low stiffness and special stiffness properties limit the application of industrial robots in sophisticated manufacturing. The subject of the paper is to investigate the influence of robot stiffness properties on machining quality in drilling application. It is found that unidirectional thrust force could induce three-directional deformation of robot which will directly lead to hole defects during drilling procedure. Firstly, starting from the special characteristics of the robot, the key role of the preload pressing force is pointed out. Equivalent stiffness model under pre-load pressing force is established and stiffness promotion coefficient is defined to evaluate the effects of pressing force quantitatively. The matching criterion of robot drilling posture and thrust force is proposed, and the optimized value of pressing force can be predicted under the condition of stable machining. Limitation on hole diameter and roundness of robot drilling is evaluated too. By applying pre-load pressing force, the stiffness of robot drilling plane is markedly improved, and the drilling stability and hole diameter accuracy are also enhanced. Finally, the proposed method is verified by drilling experiments.

Temperatures generated during implant site preparation with conventional drilling versus single-drill method: an ex-vivo human mandible study

Bone overheating during osteotomy is a potential cause of necrosis and consequent failure of dental implant osseointegration. The aim of this study is to identify any differences between conventional osteotomy with drills of increasing size and the use of a single drill in terms of the temperature increase in the bone during implant site preparation. Thirty-eight implant sites were prepared in ex vivo human mandibles, 19 using the conventional method with drills of increasing diameter (group A) and 19 using a single-drill method (group B), with no irrigation in either procedure. An infrared thermometer was used to measure the temperature difference (T°) induced by the drills at each site. Student's t-test (with P<0.05) was used to compare the temperature increase induced by the last drill in group A, and by the single drill in group B. The mean ΔT° in group A was 0.64 °C, while in group B it was 1.47 °C. The difference between the temperatures obtained in the two groups was statistically significant (P=0.0073). In statistical terms, the two methods differ significantly in the temperature increase induced by the drilling procedure, but this difference is clinically irrelevant.