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Efficient high-speed bone drilling with an automated osteonecrosis avoidance strategy is a very fascinating task to the orthopaedic surgeons. Several drilling parameters such as drill diameter, speed, and feed rate can affect the performance of drilling in terms of generated temperature and thrust force. This research is conducted using a high-speed mini CNC machine to investigate bone drilling parameters’ impact on the outputs. Here, a piece of swine bone has been used for testing material and an automated cooling system based on proportional controller (P) was developed to prevent osteonecrosis. Further, a hybrid Artificial Neural Network-Genetic Algorithm (ANN-GA) model has been proposed based on the different experimental findings. ANN predicts output variables, and GA determines the optimal input drilling parameters by minimizing the ANN model of temperature and force. The simulation results revealed that drill diameter of 1.838 mm, speed of 17,880 rpm, and feed rate of 9.973 mm/min minimized the output temperature generated on swine bone. Similarly, diameter of 1.5 mm, speed of 16,582 rpm, and 10 mm/min feed rate helped to minimize the generated force during drilling. The proposed model has been validated by conducting new experiments based on these obtained optimal parameters. [ABSTRACT FROM AUTHOR]

The orthopedic manipulation of bone drilling is performed during the osteosynthesis of bone fractures. It is characterized by a set of input and output parameters. The temperature in the tool-bone interaction zone is one of the most important output parameters of the drilling process. The increase in temperature above a certain threshold causes thermal osteonecrosis of bone cells and all the resulting negative consequences. This work presents a way of drill-bit upper limit temperature calculation during robotized bone drilling process. The temperature estimation and temperature calculation methodology is based on the energy conversion in the bone-robot system, preserving the overall energy balance according to the universal energy conservation law. The bone drilling is performed by using of robot ODRO. Fresh porcine femur bones are used as specimens in the experiments which validate the theoretical results. The real time temperature data during drilling are obtained using a non-contact temperature sensor. A computational approach is developed for estimating the temperature in the drilling zone on the base of the obtained data.The temperature estimation data can be used to control of the cutting condition during a robotic bone drilling process in order to obtain an optimal outcome. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing technology presents a promising avenue for the development of affordable neurosurgical simulation models, addressing many challenges related to the use of cadavers, animal models, and direct patient engagement. The aim of this study is to introduce and evaluate a new high-fidelity neurosurgical simulation model targeted for both burr hole and craniotomy procedures. 12 different 3D-printed skull models were manufactured using 5 different materials (polyether ether ketone, White Resin, Rigid 10K, BoneSTN, and SkullSTN) from 3 different 3D print processes (fused filament fabrication, stereolithography [SLA], and material jetting). Six consultant neurosurgeons conducted burr holes and craniotomies on each sample while blinded to these manufacturing details. Participants completed a survey based on the qualities of the models, including mechanical performance, visual appearance, interior feeling, exterior feeling, sound, overall quality, and recommendations for training purposes based on their prior experience completing these procedures on human skulls. This study found that the multimaterial SLA-printed models consisting of White Resin for the outer table and Rigid 10K for the diploe and inner table were successful in replicating a human skull for burr hole and craniotomy simulation. This was followed by the porous General BoneSTN preset material on a Stratasys J750 Digital Anatomy Printer. The findings indicate that widely accessible and economical desktop SLA 3D printers can provide an effective solution in neurosurgical training, thus promoting their integration in hospitals. [ABSTRACT FROM AUTHOR]

Bone drilling is a mechanical, thermal coupling process utilized in orthopedics for provision of rigid internal fixation and treatment of fractured bone. Rotary ultrasonic-assisted bone drilling (RUABD) has achieved noteworthy interest in orthopedic practice due to its ability to enhance biomechanical pullout strength. Drilling parameters used during orthopedic surgeries significantly impact the holding power, initial implant stability and pullout strength. It is difficult for surgeons to predict push-out strength at the interface of bone and screw. An intelligent approach could involve utilizing machine learning (ML) to train and test independent drilling parameters, thereby predicting pullout strength and optimizing holding strength. Therefore, the present work focused on leveraging ML models during RUABD to predict pullout strength at the bone-screw interface. The monitoring of various drilling parameters (including insertion angle, feedrate, rotational speed, and ultrasonic amplitude) was conducted. Multiple ML models were employed to forecast the pullout strength at the interface between bone and screw. The SVR-based ML model exhibited the most accurate prediction among all models, with the lowest error metrics observed. ML algorithms can be leveraged for robust prediction of biomechanical pullout strength to upsurge holding strength and avoid screw loosening. [ABSTRACT FROM AUTHOR]

This study evaluates the thermal impact of a one-drill protocol for osteotomy preparation in dental implant surgery. Our findings demonstrate a significant reduction in heat generation compared to traditional sequential drilling, suggesting potential benefits for implant osseointegration and patient comfort. Specifically, the one-drill protocol was associated with lower peak temperatures and a reduced duration of elevated temperatures. These findings suggest that the one-drill protocol may contribute to improved implant stability and reduce the risk of thermal-induced bone damage. While further research is needed to confirm these findings in clinical settings, the results of this study provide promising evidence for the potential advantages of the one-drill protocol in dental implant surgery. Additionally, the one-drill protocol may offer simplified surgical workflows and reduced instrument management, potentially leading to improved efficiency and cost-effectiveness in dental implant procedures. [ABSTRACT FROM AUTHOR]

Abstract Background With orthopedic surgery increasing year on year, the main challenges in bone drilling are thermal damage, mechanical damage, and drill skid. The need for new orthopedic drills that improve the quality of surgery is becoming more and more urgent. Methods Here, we report the skidding mechanism of drills at a wide range of inclination angle and propose two crescent drills (CDTI and CDTII). The anti-skid performance and drilling damage of the crescent drills were analyzed for the first time. Inclined bone drilling experiments were carried out with crescent drills and twist drills and real-time drilling forces and temperatures were collected. Results The crescent drills are significantly better than the twist drill in terms of anti-skid, reducing skidding forces, thrust forces and temperature. The highest temperature is generated close to the upper surface of the workpiece rather than at the hole exit. Finally, the longer crescent edge with a small and negative polar angle increases the rake angle of the cutting edge and reduces thrust forces but increases skidding force and temperature. This study can promote the development of high-quality orthopedic surgery and the development of new bone drilling tools. Conclusion The crescent drills did not skid and caused little drilling damage. In comparison, the CDTI performs better in reducing the skidding force, while the CDTII performs better in reducing the thrust force.

Abstract Objective Conical orthopedic drill bits may have the potential to improve the stabilization of orthopedic screws. During perforations, heat energy is released, and elevated temperatures could be related to thermal osteonecrosis. This study was designed to evaluate the thermal behavior of an experimental conical drill bit, when compared to the conventional cylindrical drill, using polyurethane blocks perforations. Results The sample was divided into two groups, according to the method of drilling, including 25 polyurethane blocks in each: In Group 1, perforations were performed with a conventional orthopedic cylindrical drill; while in Group 2, an experimental conical drill was used. No statistically significant difference was observed in relation to the maximum temperature (MT) during the entire drilling in the groups, however the perforation time (PT) was slightly longer in Group 2. Each drill bit perforated five times and number of perforations was not correlated with a temperature increase, when evaluated universally or isolated by groups. The PT had no correlation with an increase in temperature when evaluating the perforations universally (n = 50) and in Group 1 alone; however, Group 2 showed an inversely proportional correlation for these variables, indicating that, for the conical drill bit, drillings with longer PT had lower MT.

Sequential drilling is a common practice in dental implant surgery aimed at minimizing thermal damage to bone. This study evaluates the thermal effects of sequential drilling and assesses modifications to drilling protocols to manage heat generation. We utilized a custom drill press and artificial bone models to test five drill bits under various protocols, including sequential drilling with different loads, spindle speeds, and peck drilling. Infrared thermography recorded temperature changes during the drilling process, with temperatures monitored at various depths around the osteotomy. The results reveal sequential drilling does not eliminate the thermal damage zone it creates (well over 70 °C). It creates harmful heat to surrounding bone that can spread up to 10 mm from the osteotomy. The first drill used in sequential drilling produces the highest temperatures (over 100 °C), and subsequent drill bits cannot remove the thermal trauma incurred; rather, they add to it. Modifying drill bit design and employing proper drilling techniques, such as reducing drilling RPM and load, can reduce thermal trauma by reducing friction. Inadequate management of heat can lead to prolonged recovery, increased patient discomfort, and potential long-term complications such as impaired bone-to-implant integration and chronic conditions like peri-implantitis. Ensuring healthy bone conditions is critical for successful implant outcomes. [ABSTRACT FROM AUTHOR]

Surgeons face a significant challenge due to the heat generated during drilling, as excessive temperatures at the bone–tool interface can lead to irreversible damage to the regenerative soft tissue and result in thermal osteonecrosis. While previous studies have explored the use of machine learning to predict the temperature rise during bone drilling, this in vitro study introduces a comprehensive approach by combining the Response Surface Methodology (RSM) with advanced machine learning techniques. The main objective lies in the comprehensive evaluation and comparison of support vector machine (SVM) and random forest (RF) models specifically for the optimization of the bone drilling parameters to prevent thermal bone necrosis. A total of 27 experiments were conducted using a multi-level factorial method, with analysis performed via the Minitab software version 19.1. Performance metrics such as the mean squared error (MSE), mean absolute percentage error (MAPE), and coefficient of determination (R2) were used to assess model accuracy. The RF model emerged as the most effective, with R2 values of 94.2% for testing and 97.3% for training data, significantly outperforming other models in predicting temperature fluctuations. This study demonstrates the superior predictive capabilities of the RF model and offers a robust framework for the optimization of surgical procedures to mitigate the risk of thermal damage. [ABSTRACT FROM AUTHOR]

Background: With orthopedic surgery increasing year on year, the main challenges in bone drilling are thermal damage, mechanical damage, and drill skid. The need for new orthopedic drills that improve the quality of surgery is becoming more and more urgent. Methods: Here, we report the skidding mechanism of drills at a wide range of inclination angle and propose two crescent drills (CDTI and CDTII). The anti-skid performance and drilling damage of the crescent drills were analyzed for the first time. Inclined bone drilling experiments were carried out with crescent drills and twist drills and real-time drilling forces and temperatures were collected. Results: The crescent drills are significantly better than the twist drill in terms of anti-skid, reducing skidding forces, thrust forces and temperature. The highest temperature is generated close to the upper surface of the workpiece rather than at the hole exit. Finally, the longer crescent edge with a small and negative polar angle increases the rake angle of the cutting edge and reduces thrust forces but increases skidding force and temperature. This study can promote the development of high-quality orthopedic surgery and the development of new bone drilling tools. Conclusion: The crescent drills did not skid and caused little drilling damage. In comparison, the CDTI performs better in reducing the skidding force, while the CDTII performs better in reducing the thrust force. [ABSTRACT FROM AUTHOR]

Objective: Conical orthopedic drill bits may have the potential to improve the stabilization of orthopedic screws. During perforations, heat energy is released, and elevated temperatures could be related to thermal osteonecrosis. This study was designed to evaluate the thermal behavior of an experimental conical drill bit, when compared to the conventional cylindrical drill, using polyurethane blocks perforations. Results: The sample was divided into two groups, according to the method of drilling, including 25 polyurethane blocks in each: In Group 1, perforations were performed with a conventional orthopedic cylindrical drill; while in Group 2, an experimental conical drill was used. No statistically significant difference was observed in relation to the maximum temperature (MT) during the entire drilling in the groups, however the perforation time (PT) was slightly longer in Group 2. Each drill bit perforated five times and number of perforations was not correlated with a temperature increase, when evaluated universally or isolated by groups. The PT had no correlation with an increase in temperature when evaluating the perforations universally (n = 50) and in Group 1 alone; however, Group 2 showed an inversely proportional correlation for these variables, indicating that, for the conical drill bit, drillings with longer PT had lower MT. [ABSTRACT FROM AUTHOR]

To ensure the prevention of thermal trauma and tissue necrosis during bone drilling in surgical procedures, it is crucial to maintain temperatures below the time- and temperature-dependent threshold of 50 °C for 30 s. However, the absence of a current standard for assessing temperatures attained during bone drilling poses a challenge when comparing findings across different studies. This article aims to address this issue by introducing a standardized testing method for acquiring thermal data during experimental bone drilling. The method requires the use of three controlled variables: infrared thermography, standard bone blocks, and a regulated drilling procedure involving a drill press with irrigation that simulates a surgeon. By utilizing this setup, we can obtain temperature data that can be effectively applied in the evaluation of other variables, such as surgical techniques or drill bit design, and translate the data into bone damage/clinical outcomes. Two surgical drill bits (2.0 mm-diameter twist drill bit and 3.3 mm-diameter multi-step drill bit) are compared using this experimental protocol. The results show the 2.0 mm bit reached significantly higher temperatures compared to the 3.3 mm bit when preparing an osteotomy (p < 0.05). The 2.0 mm drill bit reached temperatures over 100 °C while the 3.3 mm drill bit did not exceed 50 °C. [ABSTRACT FROM AUTHOR]

Biological bone materials, complex and anisotropic, require precise machining in surgeries. Bone drilling, a key technique, is susceptible to increased friction from tool wear, leading to excessive forces and high temperatures that can damage bone and surrounding tissues, affecting recovery. This study develops a monitoring platform to assess tool wear during bone drilling, employing an experimental setup that gathers triaxial force and vibration data. A recognition model using a bidirectional long short-term memory network (BI-LSTM) with a multi-head attention mechanism identified wear levels. This model, termed ABI-LSTM, was optimized and benchmarked against SVR, RNN, and CNN models. The results from implementing the ABI-LSTM-based monitoring system demonstrated its efficacy in detecting tool wear, thereby potentially reducing surgical risks such as osteonecrosis and drill breakage, and enhancing surgical outcomes. [ABSTRACT FROM AUTHOR]

The orthopedic manipulation of bone drilling is performed during the osteosynthesis of bone fractures. It is characterized by a set of input and output parameters. The temperature in the tool-bone interaction zone is one of the most important output parameters of the drilling process. The increase in temperature above a certain threshold causes thermal osteonecrosis of bone cells and all the resulting negative consequences. This work presents a way of drill-bit upper limit temperature calculation during robotized bone drilling process. The temperature estimation and temperature calculation methodology is based on the energy conversion in the bone-robot system, preserving the overall energy balance according to the universal energy conservation law. The bone drilling is performed by using of robot ODRO. Fresh porcine femur bones are used as specimens in the experiments which validate the theoretical results. The real time temperature data during drilling are obtained using a non-contact temperature sensor. A computational approach is developed for estimating the temperature in the drilling zone on the base of the obtained data.The temperature estimation data can be used to control of the cutting condition during a robotic bone drilling process in order to obtain an optimal outcome.

Frequently orthopedic surgeries require mechanical drilling processes especially for inserted biodegradable screws or removing small bone lesions. However mechanical drilling techniques induce large number of forces as well as have substantially lower material removal rates resulting in prolong healing times. This study focuses on analyzing the impact of quasi-continuous laser drilling on the bone's surface as well as optimizing the drilling conditions to achieve high material removal rates. An ex-vivo study was conducted on the cortical region of desiccated bovine bone. The laser-based drilling on the bovine bine specimens was conducted in an argon atmosphere using a number of laser pulses ranging from 100 to 15,000. The morphology of the resulting laser drilled cavities was characterized using Energy dispersive Spectroscopy (EDS) and the width and depth of the drills were measured using a laser based Profilometer. Data from the profilometer was then used to calculate material removal rates. At last, the material removal rates and laser processing parameters were used to develop a statistical model based on Design of Experiments (DOE) approach to predict the optimal laser drilling parameters. The main outcome of the study based on the laser drilled cavities was that as the number of laser pulses increases, the depth and diameter of the cavities progressively increase. However, the material removal rates revealed a decrease in value at a point between 4000 and 6000 laser pulses. Therefore, based on the sequential sum of square method, a polynomial curve to the 6th power was fit to the experimental data. The predicted equation of the curve had a p-value of 0.0010 indicating statistical significance and predicted the maximum material removal rate to be 32.10 mm3/s with 95%CI [28.3,35.9] which was associated with the optimum number of laser pulses of 4820. Whereas the experimental verification of bone drilling with 4820 laser pulses yielded a material removal rate of 33.37 mm3/s. Therefore, this study found that the carbonized layer formed due to laser processing had a decreased carbon content and helped in increasing the material removal rate. Then using the experimental data, a polymetric equation to the sixth power was developed which predicted the optimized material removal rate to occur at 4820 pulses. [ABSTRACT FROM AUTHOR]

The bone drilling process has been used in orthopedic surgical procedures to remove bones and create artificial joint holes. Heat generation due to the cutting temperature is a critical problem, which leads to permanent damage to bone tissues and thermal necrosis. Previous studies noted that the temperature changes during the drilling process depend on the cutting forces. Temperatures above 50 °C can damage the surface of the drilled hole. Machining parameters such as the feed rate affect the generation of the cutting force and temperature. Low ranges of surface velocity and feed rate significantly increase the surgery time, thereby increasing the thermal exposure time. Therefore, selecting the appropriate cutting parameters considering the machining time is essential to improve the bone surgery process. A bone cell has anisotropic material properties owing to is orientation. Bones consist of osteons and lamellae, which is analogous to the fiber and matrix in composites such as carbon fiber-reinforced polymer. The finite element (FE) method can be used to analyze the mechanism of the composites machining process, and this requires the use of a failure model. Hill's potential theory is used in the failure analysis of anisotropic materials. Although Hou's failure model yields better analysis results than Hill's theory, the former is suitable for predicting the failure of brittle materials. Bones are more ductile than composites owing to the presence of minerals and moisture. This paper proposes an FE analysis model for three-dimensional orthopedic surgical drilling to predict the cutting force. The performance of the FE model was validated by comparing the obtained results with the cutting force measured during experiments using bovine orthopedic bone. Orthopedic bone has an anisotropic structure. The structure consists of packed osteons and lamellae, reflecting a directional property similar to that of the composites structure. Therefore, the FE model considered the anisotropic material behavior with a failure criterion. The Hashin and Puck models were implemented in the FE model to analyze the failure of the osteons and lamellae, respectively. The thrust force is higher than the radial and tangential forces, which contributes to temperature increase during the drilling process. Therefore, the thrust forces obtained from the experiment and FE model at various drilling parameters were compared to validate the performance of the FE model. At a higher feed rate, the FE model yielded good prediction accuracy with a low error of approximately 3.37 %. Based on the predicted thrust force, the heat generated on the surface of the drilled hole was calculated to predict the degree of necrotic surface. [ABSTRACT FROM AUTHOR]

Bone drilling is a common procedure used to create pilot holes for inserting screws to secure implants for fracture fixation. However, this process can increase bone temperature and the excessive heat can lead to cell death and thermal osteonecrosis, potentially causing early fixation failure or complications. We applied a three-dimensional dynamic elastoplastic finite element model to evaluate the propagation and distribution of heat during bone drilling and assess the thermally affected zone (TAZ) that may lead to thermal necrosis. This model investigates the parameters influencing bone temperature during bone drilling, including drill diameter, rotational speed, feed force, and predrilled hole. The results indicate that our FE model is sufficiently accurate in predicting the temperature rise effect during bone drilling. The maximum temperature decreases exponentially with radial distance. When the feed forces are 40 and 60 N, the maximum temperature does not exceed 45 °C. However, with feed forces of 10 and 20 N, both the maximum temperatures exceed 45 °C within a radial distance of 0.2 mm, indicating a high-risk zone for potential thermal osteonecrosis. With the two-stage drilling procedure, where a 2.5 mm pilot hole is predrilled, the maximum temperature can be reduced by 14 °C. This suggests that higher feed force and rotational speed and/or using a two-stage drilling process could mitigate bone temperature elevation and reduce the risk of thermal osteonecrosis during bone drilling. [ABSTRACT FROM AUTHOR]

This study evaluates the thermal impact of a one-drill protocol for osteotomy preparation in dental implant surgery. Our findings demonstrate a significant reduction in heat generation compared to traditional sequential drilling, suggesting potential benefits for implant osseointegration and patient comfort. Specifically, the one-drill protocol was associated with lower peak temperatures and a reduced duration of elevated temperatures. These findings suggest that the one-drill protocol may contribute to improved implant stability and reduce the risk of thermal-induced bone damage. While further research is needed to confirm these findings in clinical settings, the results of this study provide promising evidence for the potential advantages of the one-drill protocol in dental implant surgery. Additionally, the one-drill protocol may offer simplified surgical workflows and reduced instrument management, potentially leading to improved efficiency and cost-effectiveness in dental implant procedures.

The positioning accuracy of medical bone drilling has a great impact on the success rate of orthopedic surgery. Due to the need for high accuracy of medical bone drilling, with use of any 6-DoF-type robotic arm to assist in drilling, a novel six-degree-of-freedom compensation positioning algorithm of robotic arm-assisted medical bone drilling is proposed, in which only position but also orientation errors of robotic end are considered, increasing positioning capability of drilling instrument end effector with position and orientation correction for medical drilling motion accurate controlling. For the different position and orientation characteristics of the robot arm controlling and measurement point/zone, position and orientation transformation from measurement to controlling point/zone is established through position and angle calibration experiments, realizing position and orientation error measured by optical tracking system from measurement point/zone to controlling point/zone. Based on 6-DoF parameter and principle of robotic arm, a positioning compensation model based on the 6-DoF position and orientation errors of robotic arm end is proposed, and iteration cycle is used for higher accuracy, realizing double correction of position and orientation of robotic arm end. The accuracy verification experiments measured by the optical tracking system shows that the average position error before and after the 6-DoF compensation positioning algorithm reduces from 1.42 mm (before compensation with DH-based inverse kinematic model) to 0.20 mm (after compensation model) and the average angle error from 0.470° to 0.046°. A bovine spine drilling experiment is carried out based on the 6-DoF compensation algorithm, and the average position error of the hole in the specific direction measured by the contour projector is 0.221 mm, achieving high positioning accuracy of bone drilling, demonstrating reliability and practical application value of medical bone drilling with the compensation of positioning algorithm. [ABSTRACT FROM AUTHOR]

Drilling through bone is widely performed in orthopedic surgeries to fix the plate and implant using bone screws. Clinical observation revealed that the mechanical and thermal damages driven by the uncontrolled drilling operations loosen the implants soon after their fixations. During fracture treatment and reconstruction surgery, the quality of the hole generated is to be considered as an important metric, and therefore drill feed rate and spindle speed, apparent bone density, drill bit geometry, and skill of the surgeon are the parameters to influence the success of the bone drilling procedure. The generation of temperature due to the conversion of mechanical work around the osteotomy site leads to irreversible thermal damage to the bone tissue, when it exceeds 47∘C. So, a non-invasive method which can identify the probability to not get a thermal osteonecrosis at the chosen drill spot can help the surgeon to strongly fix the implant around the defect site. To make this happen, the in-situ bone temperatures measured in the earlier study when drilling with a 3.20 mm diameter drill bit was used for the investigation. As a procedure, the test statistics and critical test statistics values were calculated, and found that the log normal and gamma density functions could best describe the bone drilling temperatures, when drilling in the radial and circumferential directions, respectively. Additionally, the CT data sets of the patient-specific femur were used to reconstruct the bone both with geometry and drilling temperature data. The Kolmogrov–Smirnov test performed to check the validity of the temperature distribution models showed a good agreement with the experimental results. The outcomes of the method can help the surgeon to choose a suitable location for the strongest fixation using CT data sets of the patient as the only input. [ABSTRACT FROM AUTHOR]

Abstract Background Guided bone regeneration (GBR) involves collecting bone autografts with high bio-quality and efficiency. The current non-irrigated low-speed drilling has been limited for broader application in bone autograft harvest due to its low efficiency, inability to conduct buccal cortical perforation, and dependence on simultaneous implant placement. Increasing the drilling speed helps improve the efficiency but may incur thermal-mechanical bone damage. Most studies have addressed thermal reactions during bone drilling on non-vital models, which is irrelevant to clinical scenarios. Little has been known about bone’s in vivo thermal profiles under non-irrigated higher-speed drilling and its influences on the resulting bone chips. Aim A novel technique for bone harvest and cortical perforation via in-situ non-irrigated higher-speed drilling was proposed and investigated for the first time. Methods The third mandible premolars of eight beagles were extracted and healed for three months. Sixteen partial edentulous sites (left and right) were randomized into four groups for bone autograft harvest without irrigation: chisel, 50 rpm drilling, 500 rpm drilling, and 1000 rpm drilling. Bone chips were harvested on the buccal plates of the missing tooth. An infrared camera and an implantable thermocouple collaboratively monitored in vivo real-time bone temperature at the drilling sites. In vitro performances of cells from bone chips, including cell number, viability, proliferation, migration, ALP activity, in vitro mineralization, mRNA transcriptional level of osteogenic genes and heat shock protein 70 (HSP-70), and HSP-70 expression at the protein level were also studied. Results 500 rpm produced mild local hyperthermia with a 2–6 °C temperature rise both on the cortical surface and inside the cortical bone. It also held comparable or enhanced cell performances such as cell number, viability, proliferation, migration, ALP activity, in vitro mineralization, and osteogenic genes expression. Conclusions In-situ non-irrigated higher-speed drilling at 500 rpm using a screw drill is versatile, efficient, and thermal friendly and improves the bio-quality of bone chips. Our novel technique holds clinical translational potential in GBR application.

Sequential drilling is a common practice in dental implant surgery aimed at minimizing thermal damage to bone. This study evaluates the thermal effects of sequential drilling and assesses modifications to drilling protocols to manage heat generation. We utilized a custom drill press and artificial bone models to test five drill bits under various protocols, including sequential drilling with different loads, spindle speeds, and peck drilling. Infrared thermography recorded temperature changes during the drilling process, with temperatures monitored at various depths around the osteotomy. The results reveal sequential drilling does not eliminate the thermal damage zone it creates (well over 70 °C). It creates harmful heat to surrounding bone that can spread up to 10 mm from the osteotomy. The first drill used in sequential drilling produces the highest temperatures (over 100 °C), and subsequent drill bits cannot remove the thermal trauma incurred; rather, they add to it. Modifying drill bit design and employing proper drilling techniques, such as reducing drilling RPM and load, can reduce thermal trauma by reducing friction. Inadequate management of heat can lead to prolonged recovery, increased patient discomfort, and potential long-term complications such as impaired bone-to-implant integration and chronic conditions like peri-implantitis. Ensuring healthy bone conditions is critical for successful implant outcomes.

Surgeons face a significant challenge due to the heat generated during drilling, as excessive temperatures at the bone–tool interface can lead to irreversible damage to the regenerative soft tissue and result in thermal osteonecrosis. While previous studies have explored the use of machine learning to predict the temperature rise during bone drilling, this in vitro study introduces a comprehensive approach by combining the Response Surface Methodology (RSM) with advanced machine learning techniques. The main objective lies in the comprehensive evaluation and comparison of support vector machine (SVM) and random forest (RF) models specifically for the optimization of the bone drilling parameters to prevent thermal bone necrosis. A total of 27 experiments were conducted using a multi-level factorial method, with analysis performed via the Minitab software version 19.1. Performance metrics such as the mean squared error (MSE), mean absolute percentage error (MAPE), and coefficient of determination (R2) were used to assess model accuracy. The RF model emerged as the most effective, with R2 values of 94.2% for testing and 97.3% for training data, significantly outperforming other models in predicting temperature fluctuations. This study demonstrates the superior predictive capabilities of the RF model and offers a robust framework for the optimization of surgical procedures to mitigate the risk of thermal damage.

During bone drilling surgery, the bone drill can generate drilling force and frictional heat, which may lead to mechanical and thermal damage to the bone tissue. This paper presents a finite element (FE) simulation of bone drilling for cortical and cancellous bone, analyzing the influence of drilling parameters on bone drilling force and temperature. The simulation results reveal the change laws of axial force and temperature during different density bone drilling for various parameters. To optimize the bone drilling parameters, the Taguchi method is applied to conduct bone drilling simulation experiments based on the FE simulation model. The optimal values of axial force and temperature are predicted and calculated under the condition of optimal drilling parameters. Furthermore, a robot bone drilling experiment platform is used to verify the bone drilling FE simulation model and the optimal parameters. The research demonstrates that the FE simulation model effectively explores the influence of drilling parameters on bone drilling force and temperature, while the Taguchi method optimizes the drill parameters to minimize the mechanical and thermal damage to the bone tissue.

Background: During bone drilling, a common procedure in clinical surgeries, excessive heat generation and drilling force can cause damage to bone tissue, potentially leading to failure of implants and fixation screws or delayed healing. With this in mind, the aim of this study was to evaluate the efficiency of ultrasonic-assisted drilling compared to conventional drilling as a potential method for bone drilling. Methods: This study examined optimal drilling parameters based on previous findings and investigated both cortical and cancellous bone. In addition to evaluating drilling force and temperature elevation, the effects of these factors on osteonecrosis and micro-crack formation were explored in ultrasonic-assisted and conventional drilling through histopathological assessment and microscopic imaging. To this end, three drilling speeds and two drilling feed-rates were considered as variables in the in vitro experiments. Furthermore, numerical modeling provided insight into temperature distribution during the drilling process in both methods and compared three different vibration amplitudes. Results: Although temperature elevations were lower in the conventional drilling, ultrasonic-assisted drilling produced less drilling force. Additionally, the latter method resulted in smaller osteonecrosis regions and did not produce micro-cracks in cortical bone or structural damage in cancellous bone. Conclusions: Ultrasonic-assisted drilling, which caused less damage to bone tissue in both cortical and cancellous bone, was comparatively more advantageous. Notably, this study demonstrated that to determine the superiority of one method over the other, we cannot rely solely on temperature variation results. Instead, we must consider the cumulative effect of both temperature elevation and drilling force.

Abstract Objectives To investigate the use of a novel technique to estimate the symmetrical placement of percutaneous bone‐anchored hearing systems (BAHS) with a guide‐marker in patients undergoing bilateral surgery with this device. Study Design Prospective cohort study. Methods A guide‐marker and anatomical landmarks were used to estimate the implant placement and transferred to the contralateral ear in 12 subjects eligible for bilateral BAHS surgery. To investigate the bilateral symmetry, preoperative tri‐dimensional (3D) computed tomography (CT) image reconstruction was used to compare the distances between the mandibular condyle and implant placement estimation (mandible‐implant distance) in both the right and left ears of the subjects. Results The guide‐marker could be used to estimate the bilateral implant placement in all subjects included in this study, simply and easily, including one subject with craniofacial malformation. The mean mandible‐implant distances were 5.37 and 5.38 cm, in the right and left ears of the subjects, respectively, and no differences were observed between them, thereby indicating optimal bilateral symmetry. Conclusion The use of the guide‐marker proved to be an effective tool to provide symmetrical placement of bilateral BAHS. We propose a novel method employing a simple guide‐marker and tracing based on symmetrical anatomical landmarks to achieve precise placement and optimal symmetry and which may be easily adopted in the surgical routine of BAHS. Level of Evidence 3.

Background: Guided bone regeneration (GBR) involves collecting bone autografts with high bio-quality and efficiency. The current non-irrigated low-speed drilling has been limited for broader application in bone autograft harvest due to its low efficiency, inability to conduct buccal cortical perforation, and dependence on simultaneous implant placement. Increasing the drilling speed helps improve the efficiency but may incur thermal-mechanical bone damage. Most studies have addressed thermal reactions during bone drilling on non-vital models, which is irrelevant to clinical scenarios. Little has been known about bone's in vivo thermal profiles under non-irrigated higher-speed drilling and its influences on the resulting bone chips. Aim: A novel technique for bone harvest and cortical perforation via in-situ non-irrigated higher-speed drilling was proposed and investigated for the first time. Methods: The third mandible premolars of eight beagles were extracted and healed for three months. Sixteen partial edentulous sites (left and right) were randomized into four groups for bone autograft harvest without irrigation: chisel, 50 rpm drilling, 500 rpm drilling, and 1000 rpm drilling. Bone chips were harvested on the buccal plates of the missing tooth. An infrared camera and an implantable thermocouple collaboratively monitored in vivo real-time bone temperature at the drilling sites. In vitro performances of cells from bone chips, including cell number, viability, proliferation, migration, ALP activity, in vitro mineralization, mRNA transcriptional level of osteogenic genes and heat shock protein 70 (HSP-70), and HSP-70 expression at the protein level were also studied. Results: 500 rpm produced mild local hyperthermia with a 2–6 °C temperature rise both on the cortical surface and inside the cortical bone. It also held comparable or enhanced cell performances such as cell number, viability, proliferation, migration, ALP activity, in vitro mineralization, and osteogenic genes expression. Conclusions: In-situ non-irrigated higher-speed drilling at 500 rpm using a screw drill is versatile, efficient, and thermal friendly and improves the bio-quality of bone chips. Our novel technique holds clinical translational potential in GBR application. [ABSTRACT FROM AUTHOR]

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To ensure the prevention of thermal trauma and tissue necrosis during bone drilling in surgical procedures, it is crucial to maintain temperatures below the time- and temperature-dependent threshold of 50 °C for 30 s. However, the absence of a current standard for assessing temperatures attained during bone drilling poses a challenge when comparing findings across different studies. This article aims to address this issue by introducing a standardized testing method for acquiring thermal data during experimental bone drilling. The method requires the use of three controlled variables: infrared thermography, standard bone blocks, and a regulated drilling procedure involving a drill press with irrigation that simulates a surgeon. By utilizing this setup, we can obtain temperature data that can be effectively applied in the evaluation of other variables, such as surgical techniques or drill bit design, and translate the data into bone damage/clinical outcomes. Two surgical drill bits (2.0 mm-diameter twist drill bit and 3.3 mm-diameter multi-step drill bit) are compared using this experimental protocol. The results show the 2.0 mm bit reached significantly higher temperatures compared to the 3.3 mm bit when preparing an osteotomy (p < 0.05). The 2.0 mm drill bit reached temperatures over 100 °C while the 3.3 mm drill bit did not exceed 50 °C.

Bone drilling is a common procedure used to create pilot holes for inserting screws to secure implants for fracture fixation. However, this process can increase bone temperature and the excessive heat can lead to cell death and thermal osteonecrosis, potentially causing early fixation failure or complications. We applied a three-dimensional dynamic elastoplastic finite element model to evaluate the propagation and distribution of heat during bone drilling and assess the thermally affected zone (TAZ) that may lead to thermal necrosis. This model investigates the parameters influencing bone temperature during bone drilling, including drill diameter, rotational speed, feed force, and predrilled hole. The results indicate that our FE model is sufficiently accurate in predicting the temperature rise effect during bone drilling. The maximum temperature decreases exponentially with radial distance. When the feed forces are 40 and 60 N, the maximum temperature does not exceed 45 °C. However, with feed forces of 10 and 20 N, both the maximum temperatures exceed 45 °C within a radial distance of 0.2 mm, indicating a high-risk zone for potential thermal osteonecrosis. With the two-stage drilling procedure, where a 2.5 mm pilot hole is predrilled, the maximum temperature can be reduced by 14 °C. This suggests that higher feed force and rotational speed and/or using a two-stage drilling process could mitigate bone temperature elevation and reduce the risk of thermal osteonecrosis during bone drilling.

Bone drilling is a common procedure in orthopedic surgery and is frequently attempted using robot-assisted techniques. However, drilling on rigid, slippery, and steep cortical surfaces, which are frequently encountered in robot-assisted operations due to limited workspace, can lead to tool path deviation. Path deviation can have significant impacts on positioning accuracy, hole quality, and surgical safety. In this paper, we consider the deformation of the tool and the robot as the main factors contributing to path deviation. To address this issue, we establish a multi-stage mechanistic model of tool–bone interaction and develop a stiffness model of the robot. Additionally, a joint stiffness identification method is proposed. To compensate for path deviation in robot-assisted bone drilling, a force-position hybrid compensation control framework is proposed based on the derived models and a compensation strategy of path prediction. Our experimental results validate the effectiveness of the proposed compensation control method. Specifically, the path deviation is significantly reduced by 56.6%, the force of the tool is reduced by 38.5%, and the hole quality is substantially improved. The proposed compensation control method based on a multi-stage mechanistic model and joint stiffness identification method can significantly improve the accuracy and safety of robot-assisted bone drilling. [ABSTRACT FROM AUTHOR]

Introduction: Avascular osteonecrosis of the femoral head (AVN) is a widespread disease affecting mostly young and active people, often exacerbating in progressive stages, ending in joint replacement. The most common joint preserving operative therapy for early stages is core decompression (CD), optional with cancellous bone grafting (CBG). For success it is vital that the necrotic area is hit and the sclerotic rim is broken by drilling into the defect zone to relieve intraosseous pressure. The aim of this study was to investigate if both techniques are precise enough to hit the center of the necrosis and if there is a difference in precision between drilling with small pins (CD) and the trephine (CBG). Patients and methods: 10 patients underwent CD, 12 patients CBG with conventional C-arm imaging. Postoperatively 3D MRI reconstructions of the necrotic area and the drilling channels were compared. The deviation of the drilling channel from the center of the necrotic area was measured. PROMs (HHS, HOOS, EQ-5D, SF-36) were evaluated to compare the clinical success of these procedures. Results: Neither with CD nor with CBG the defect zone was missed. The drilling precision of both procedures did not differ significantly: distance to center 3.58 mm for CD (range 0.0–14.06, SD 4.2) versus 3.91 mm for CBG (range 0.0–15.27, SD 4.7). PROMs showed no significant difference. Conclusion: Concerning the most important difference between the two procedures—the surgical higher demanding technique of CBG—we suggest applying the less invasive technique of CD alone. [ABSTRACT FROM AUTHOR]

During bone drilling surgery, the bone drill can generate drilling force and frictional heat, which may lead to mechanical and thermal damage to the bone tissue. This paper presents a finite element (FE) simulation of bone drilling for cortical and cancellous bone, analyzing the influence of drilling parameters on bone drilling force and temperature. The simulation results reveal the change laws of axial force and temperature during different density bone drilling for various parameters. To optimize the bone drilling parameters, the Taguchi method is applied to conduct bone drilling simulation experiments based on the FE simulation model. The optimal values of axial force and temperature are predicted and calculated under the condition of optimal drilling parameters. Furthermore, a robot bone drilling experiment platform is used to verify the bone drilling FE simulation model and the optimal parameters. The research demonstrates that the FE simulation model effectively explores the influence of drilling parameters on bone drilling force and temperature, while the Taguchi method optimizes the drill parameters to minimize the mechanical and thermal damage to the bone tissue. [ABSTRACT FROM AUTHOR]

Hybrid polymer composites are utilized in biomechanical design and orthopedic surgery training to imitate the thermomechanical behavior of human bones. Despite extensive research on the mechanics of hybrid composites in biomechanical design, information on their thermomechanical response during orthopedic drilling operations is scarce. This paper presents a new experimental study to characterize the force and temperature generated during the drilling of hybrid composites that simulate human bones. To simulate the hybrid multi-layer structure of bones, the studied composite comprises a Polyurethane core sandwiched between Glass-Fiber Reinforced Polymer (GFRP) layers—the former resembling the cancellous part of the bone and the latter cortical layers. This study also identifies an empirical relationship between thrust force, temperature, drilling feed and speed, and composite composition. Empirical models are developed using multivariate polynomial regression (MPR) and artificial neural network (ANN) to predict the force and temperature during drilling. The models have a correlation coefficient of above 0.9 between predicted and measured results and can be used to improve orthopedic drilling design and control. [ABSTRACT FROM AUTHOR]

A serious problem associated with orthopedic bone drilling manipulation is the so-called thermal osteonecrosis (TO). This problem occurs because the drilling manipulation generates heat, and the amount of heat depends on the drilling conditions. This work presents the experimental evaluation of the temperature during automated bone drilling by using a handheld Orthopedic bone Drilling Robot ODRO. Up to now, such experimental results related to temperature evaluation in bone drilling by robots have not been presented. Fresh porcine and bovine femur bones were specimens in the experiments. The increase in bone temperature during drilling was measured by a thermal infrared camera. Thermographic sequence images were recorded, processed and visualized using specialized software, which allows to capture accurately the moment of drill bit penetration through the bone and its extraction when going back to initial position. The results showed that under given feed rate and drill speed, when using a new drill bit, the temperature value during porcine femur drilling exceeded the critical threshold of 50 °C for less than 2 s, and thermal osteonecrosis does not occur. When using a worn-out drill bit, the temperature value during bovine femur drilling significantly exceeded the threshold of 50 °C, and thermal osteonecrosis occurs. Thus, to guarantee bone drilling without the risk of thermal osteonecrosis, the automated drilling should be executed with the simultaneous control of speed of drill bit and feed rate. This is possible to be achieved only by robotic execution of the manipulation.

Abstract Objective The aim of this study was to determine the long-term efficacy of four steps of operation on the treatment of maxillary sinus (MS) inverted papilloma (IP). Methods 83 patients who were diagnosed with IP that originated from the MS, underwent four step procedure of attachment sites, including mucosal stripping, periosteum ablation, bone drilling and bone ablation and had postoperative follow-up of 3 years were enrolled. Results Of the 83 patients, 59 (71.1%) patients were primary surgery and revision surgery in 24 (28.9%), single attachment was in 31(37.3%) patients and multifocal attachments in 52 (62.7%).When the numbers were not mutually exclusive, the most common origin sites of IPs were the medial wall in 54 (37.2%), lateral wall in 29 (20.0%), anterior wall in 18 (12.4%), inferior wall in 22 (15.2%), posterior in 15 (10.3%), and superior wall in 7 (4.8%). Large MMA alone was performed in 5 (6.0%), MMA combined with medial maxillectomy 76 (91.6%), and MMA combined with Caldwell-Luc approach in 2 (2.4%). No major intra- or postoperative complications were observed. The average follow-up was 41 months (range, 37–61 months). CT and endoscope showed that tumor and symptom recurrence occurred in 2 patients (2.41%). In addition, although the opening of antrostomy was closed and CT revealed the uniform soft tissue shadow and hyperostosis of MS in 11(13.3%) patients, they didn’t report any symptoms and showed well epithelization of middle meatus mucosa. Conclusion The four steps of operations of attachment sites of MS IP, including mucosal stripping, periosteum ablation, bone drilling and bone ablation, may effectively prevent the recurrence of MS IP.

Background: The thermal effect correlated with implant osteotomy could produce significant effects on the healing process and fixture osseointegration. The aim of the present investigation was to assess the heat generation and surface wearing of dental implant drills and manual tappers during simulated osteotomies on animal ribs. Methods: Steel drills (20 units per type) and tappers (20 units per type) were evaluated for a total of 30 osteotomies. The infrared thermal analysis was performed at the first and thirtieth osteotomy. The surface alteration and wearing was assessed by energy dispersive spectroscopy–scanning electron microscopy (EDS-SEM) prior to and after use. Conclusions: The drill material produced a non-significant temperature change during bone osteotomy. Lower heating was reported for manual tappers in favor of a manual osteotomy instead rotary instruments.

Objectives Traditional manual drilling during hip fracture fixation can easily lead to unstable fixation and vascular damage. This study aimed to investigate a safe and easy‐to‐use robot‐assisted method to automatically drill bone and distinguish critical bone drilling states with high accuracy in real‐time for the bone hole‐making process during hip fracture fixation. Methods A bone‐drilling robotic system was designed to automatically create holes in the femoral neck. Four fresh pig femurs were drilled at the posterosuperior femoral neck using three modes: “all‐in” (AI), “in‐out‐in” (IOI), and “percutaneous fixation” (PF). A high‐frequency accelerometer captured the generated vibrations of the drill handle, which were then transferred to a personal computer using a data acquisition card. Five bone drilling states are defined, including: “drill idling,” “initial drilling,” “in the cancellous bone,” “out the femoral neck,” and “in the cortical bone.” The harmonic distribution of the vibration signal was extracted by fast Fourier transform (FFT) and used as a critical feature to identify different drilling states. To prove the difference in the harmonic distribution at different drilling states, an independent sample t‐test was used to compare the percentage of the first harmonic amplitude in the first 10 harmonics at each drilling state. A neural network classifier was trained with the frequency spectrum as the input and the drilled state as the output to distinguish the critical bone drilling states with high accuracy in real‐time. The classifier was trained and tested on four specimens to ensure that the surgical robot could accurately identify the five drilling states. Results In each specimen, the harmonic distributions of the drilling vibration at different drilling modes were significantly different (p

Aims: The aim of the present study is to evaluate the clinical applicability of laser energy during an oro-nasal endoscopic approach (ONEA) in the management of the anterior maxillary sinus wall. Methods: An experiment on three adult human cadavers was performed to study the nasal cavities with angled rigid scopes and using the ONEA technique. In order to evaluate the effectiveness of laser energy on the bone, the drilling effect was compared to laser energy (1470 nm diode laser, continuous wave, power 8, 9 and 10 W). Results: Compared to a rigid angled scope, the ONEA technique allowed complete visualization of the anterior wall of the maxillary sinus. Microscopic analysis of frontal bone revealed similar bone Exeresis with high-speed drilling (270.28 μm) and laser approaches (285.73–456.6 μm). Conclusions: The laser ONEA technique is an innovative, mini-invasive, and safe approach to the anterior wall of the maxillary sinus. Additional study is warranted to further develop this technique. [ABSTRACT FROM AUTHOR]

The functional aspect of preservation of every healthy anatomical structure, particularly the ossicles, non-diseased mastoid cortex and middle ear mucosa, and to achieve this by transacanal endoscopic dual hand approach to middle ear, aditus and mastoid antrum with minimal posterior atticotomy and proximal aditotomy. The prospective study has been conducted over a period of 12 years from 2009 to 2021 in the Jorhat Medical College, Assam Medical College and Niramoy Hospital, Jorhat, Assam. Follow up was for a minimum of 4 years. The current study was a prospective hospital based study, carried out from May 1st, 2009 to April 30th, 2021 involving 157 subjects from 18 to 65 years with mean age of 38 + 2.5. Graft uptake rate of 93.6%. Minimal atticotomy with proximal aditotomy offers a clear view of the antrum with angled scopes of 30 degree and 45 degree and if any disease is located it can be removed through the transcanal approach with angled instruments and aditus patency can be confirmed by visual inspection. Hence, decreasing the need of unnecessary bone drilling as done with cortical mastoidectomy to create a parallel view.The endoscopic ear surgeries done with "dual hand endo-holder" were uneventful and much more comfortable as compared to the single hand technique. Functional approach by minimizing bone drilling, reestablishment of ventilation pathways and preservation of ossicles with disease clearance give better postoperative results in long term follow-up. [ABSTRACT FROM AUTHOR]

Graphical abstract A temperature exceeding the safety threshold and excessive drilling force occurring during bone drilling may lead to irreversible damage to bone tissue and postoperative complications. Previous studies have shown that vibration-assisted drilling methods could have lower temperatures and drilling forces than those of the conventional drilling method; we hypothesized that the main reason for these reductions stems from the differences in the transient machining processes between conventional and vibration-assisted drilling methods. To investigate these differences, comparative experiments and two-dimensional finite element models were performed and developed. The differences in the transient machining processes were verified by experimentation and clearly exhibited by the finite element models. Compared with the steady cutting process that produced continuous-spiral chips in the conventional drilling method, transient machining in the low-frequency vibration-assisted drilling method was a periodically dynamic cutting–separation process that produced uniform petal chips with specific settings of drilling and vibration parameters. Moreover, the transient machining process in the ultrasonic vibration-assisted drilling method was transformed into a combined action with high-speed impact and negative rake angle cutting processes; this action produced a large proportion of powdery chips. Therefore, it could be concluded that the superposed axial vibration significantly changed the transient machining process and radically changed the mechanical state and thermal environment; these changes were the main reason for the apparent differences in the drilling performance levels. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate a new guided drill system (MIPS) for placement of bone-anchored hearing systems (BAHS) with respect to cutting performance, generation of heat, and distortion of the bone during drilling and compare it with a conventional drill system (Ponto). Further, the role of irrigation and drilling procedure with respect to the degree of heat generation was evaluated. Materials and Methods: Compact artificial bone was subjected to each drill in the two systems (conventional vs guided) while measuring thrust force, torque, and temperature. The temperature changes, induced during different drilling procedures, were measured by thermocouples positioned 0.5 mm from the periphery of the drill tract. The degree of bone damage was evaluated histologically after drilling in bovine, compact, tibial bone. Results: The mean thrust energy was significantly lower for the drills of the guided system compared with the corresponding conventional drills. In contrast, the mean torque energy was higher using the guided system but only for the initial guide drilling step. Whereas twist drills in combination with a guided drilling approach (MIPS) generated relatively more heat, especially during a prolonged drilling sequence, it was more forgiving in the case of impaired irrigation. The histologic evaluation showed relatively more even cut surfaces and fewer microcracks in the osteotomy wall using the guided system compared with the conventional system. Conclusion: Provided the clinically recommended drilling procedure was adhered to, the absolute temperatures using either a conventional drill system or a guided drill system were below the threshold for thermally induced tissue damage. This study suggests that the guided MIPS system conveys a promising design for an efficient and still-safe osteotomy site preparation for BAHS placement. [ABSTRACT FROM AUTHOR]

The purpose of this study is to propose a quantitative assessment scheme to help with surgical bone drilling training. This pilot study gathered and compared motion and force data from expert surgeons (n = 3) and novice residents (n = 6). The experiment used three‐dimensional printed bone simulants of young bone (YB) and osteoporotic bone (OB), and drilling overshoot, time, and force were measured. There was no statistically significant difference in overshoot between the two groups (p = 0.217 for YB and 0.215 for OB). The results, however, show that the experts took less time (mean = 4.01 s) than the novices (mean = 9.98 s), with a statistical difference (p = 0.003 for YB and 0.0001 for OB). In addition, the expert group performed more consistently than the novices. The force analysis further revealed that experts used a higher force to drill the first cortical section and a noticeably lower force in the second cortex to control the overshoot (approximate reduction of 5.5 N). Finally, when drilling time and overshoot distance were combined, the motion data distinguished the skill gap between expert and novice drilling; the force data provided insight into the drilling mechanism and performance outcomes. This study lays the groundwork for a data‐driven training scheme to prepare novice residents for clinical practice. [ABSTRACT FROM AUTHOR]

Biotribology is applied to study the friction, wear, and lubrication of biological systems or natural phenomena under relative motion in the human body. It is a multidisciplinary field and tribological processes impact all aspects of our daily life. Tribological processes may occur after the implantation of an artificial device in the human body with a wide variety of sliding and frictional interfaces. Blood is a natural bio-lubricant experiencing laminar flow at the lower screw velocities associated with drilling implants into bone, being a viscoelastic fluid with viscous and fluid characteristics. The viscosity comes from the blood plasma, while the elastic properties are from the deformation of red blood cells. In this study, drilling parameters according to material properties obtained by Finite Element Analysis are given. The influence of blood on the resulting friction between the surfaces is demonstrated and correlated with mechanical and biological consequences, identifying an innovative approach to obtaining a new lubricant parameter for bone drilling analysis. The lubrication parameter (HN) found within the limitations of conditions used in this study is 10.7 × 10−7 for both cortical bone (D1) and spongy bone (D4). A thermal-structural analysis of the densities of the soft bone (D4) and hard bone (D1) shows differences in only the equivalent stress values due to the differences in respective Young moduli. The natural occurrences of blood as a lubricant in bone-screw perforations are poorly investigated in the literature and its effects are fundamental in osseointegration. This work aims to elucidate the relevance of the study of blood as a lubricant in drilling and screwing implants into bone at lower speeds. [ABSTRACT FROM AUTHOR]

A serious problem associated with orthopedic bone drilling manipulation is the so-called thermal osteonecrosis (TO). This problem occurs because the drilling manipulation generates heat, and the amount of heat depends on the drilling conditions. This work presents the experimental evaluation of the temperature during automated bone drilling by using a handheld Orthopedic bone Drilling Robot ODRO. Up to now, such experimental results related to temperature evaluation in bone drilling by robots have not been presented. Fresh porcine and bovine femur bones were specimens in the experiments. The increase in bone temperature during drilling was measured by a thermal infrared camera. Thermographic sequence images were recorded, processed and visualized using specialized software, which allows to capture accurately the moment of drill bit penetration through the bone and its extraction when going back to initial position. The results showed that under given feed rate and drill speed, when using a new drill bit, the temperature value during porcine femur drilling exceeded the critical threshold of 50 °C for less than 2 s, and thermal osteonecrosis does not occur. When using a worn-out drill bit, the temperature value during bovine femur drilling significantly exceeded the threshold of 50 °C, and thermal osteonecrosis occurs. Thus, to guarantee bone drilling without the risk of thermal osteonecrosis, the automated drilling should be executed with the simultaneous control of speed of drill bit and feed rate. This is possible to be achieved only by robotic execution of the manipulation. [ABSTRACT FROM AUTHOR]

Purpose: There is no clinical consensus to determine the right balance between underpreparation and marginal bone level changes. The purpose of this systematic review and meta-regression was to investigate the influence of the type of drilling preparation of the implant site in relation to the bone mineral density on the clinical success, expressed in terms of the MBL and implant failure rate. Study Selection: A thorough search was performed using the digital databases MEDLINE PubMed, EMBASE, and Cochrane Central Register of Controlled Trials by entering research lines or various combinations of free words. The main keywords used were “dental implants”, “bone density”, and “torque”. Results: The mean bone resorption in the conventional preparation group was -0.43 (± 0.28) mm, whereas it was -0.80 (± 0.37) mm in the underprepared group. For the D1/D2/D3 bone group, the slope was significantly different from zero and linearity; the D4 bone group slope was not significantly different from zero and was almost parallel, although it was significantly different from linearity. The box and whiskers plot shows that the MBL in underprepared sites tended to be significantly higher with a higher variation than that in conventionally prepared sites. Conclusions: Within its limits, our meta-regression analysis showed that MBL is influenced by the type of drilling preparation and bone mineral density. In particular, a lower MBL was observed in the D1 bone with conventional preparation than with underpreparation. Moreover, a greater implant-to-osteotomy site mismatch was positively associated with greater MBLs in the bone densities of D1/D2/D3. [ABSTRACT FROM AUTHOR]

To examine the influence of the distance between adjacent implant osteotomies on heat accumulation in the inter-osteotomy area, two experimental groups with 15 pairs of osteotomies in Type II polyurethane blocks were compared: 7 mm inter-osteotomy separations (Group A, n = 15) and 14 mm inter-osteotomy separations (Group B, n = 15). An infrared thermographic analysis of thermal changes in the inter-osteotomy area was completed. A one-way analysis of variance (ANOVA) and Fisher post-test were used to determine group differences. Higher temperatures were recorded in Group A at the coronal and middle levels compared to the apical level in both groups. The temperature reached max temperatures at T80s and T100s. In Group A, the threshold for thermal necrosis was exceeded. Meanwhile, Group B did not reach the threshold for thermal necrosis. Preparing adjacent implant osteotomies in dense bone with a 7 mm separation between their centers increases the temperature in the inter-osteotomy area, exceeding the threshold for bone thermal necrosis; meanwhile, increasing the distance between osteotomies reduces the thermal accumulation and the risk for thermal necrosis. [ABSTRACT FROM AUTHOR]

K-wire drilling is commonly used in orthopedic surgeries, generating significant heat that can lead to bone thermal osteonecrosis. To understand the heat propagation and thermal damage region, a mathematical model of the negative rake angle on the hollow notched K-wire was established. Subsequently, a theoretical model of the shear angle for this negative rake angle was proposed. Based on these models, a comprehensive theoretical model of the heat flux was derived. The accurate heat flux was determined using the theoretical values, and experimental temperature data through inverse heat transfer method (IHTM). This heat flux was then applied in a finite element analysis to simulate the heat transfer process and identify thermal damage regions under different drilling conditions. Results showed that the thermal damage region of bone with a solid K-wire, hollow notched K-wire without cooling, with air cooling, and with water cooling were approximately 6.4 mm, 3.2 mm, 2.6 mm, and 4.8 mm in width, respectively, and 6.79 mm, 6.45 mm, 6.39 mm, and 6.58 mm in depth, respectively. This study demonstrates that the hollow notched K-wire with air cooling is a potential solution to reduce the thermal damage region, thereby accelerating patient recovery. [ABSTRACT FROM AUTHOR]