Drilling Sequence Research Articles

Determining of Well Drilling Sequence for Investment Analysis using Monte Carlo Simulation in Upstream Oil and Gas Company in East Kalimantan, Indonesia

Electrical construction company that experienced in making Well Head Control Panels (WHCP) has difficulties to decide acceptance of investment in WHCP contracts raised with their client in upstream oil and gas company. The difficulty mostly due to uncertainty of client well drilling sequence. The electrical construction company need to financial investment analysis includes material purchasing, shipping, fabrication and delivery of WHCPs need to be done to make sure they make a profit. It is crucial for electrical construction company used correct forecasting method to determine schedule of client’s request. Monte carlo forecasting method is used to predict the well drilling sequence. The well drilling sequence data for 12 months is used to determine 24 months well drilling sequence operation with result 179 wells with normal distribution and 167 wells with triangular distribution.

A maximum entropy deep reinforcement learning method for sequential well placement optimization using multi-discrete action spaces

Well placement optimization is a crucial method to solve the planar conflicts in reservoir development, mainly to determine the optimal well locations and drilling sequence to maximize the economic benefits of reservoir development. However, the current well placement optimization methods face the problems of high-dimensional discretization of optimization variables and lack of effective incentives for policy exploration, which make it challenging to improve the global optimization ability (the ability to jump out of locally optimal solutions in time and continuously search for better solutions in the whole optimization process) and real-time adjustability of the well placement optimization methods under limited numerical simulation times. In this paper, we propose a new sequential well placement optimization method, based on the Discrete Soft Actor-Critic Algorithm (DSAC), which incorporates the maximum entropy mechanism to formulate well placement and drilling sequencing schemes more efficiently and maximize the net present value (NPV) over the entire life cycle of reservoir development. Specifically, the method models the well placement optimization problem as a Markov Decision Process (MDP) and achieves sequential well placement optimization by training a Deep Reinforcement Learning (DRL) agent that maps reservoir states to a stochastic policy of well placement variables as well as evaluates the value function of the current policy. The DRL agent can determine the optimal infill well location in real-time based on the reservoir state at different times during the development process, thus obtaining the optimal drilling sequence. The proposed method in this paper has two innovations. First, by reconstructing the large-scale discrete action space of well placement optimization variables into multi-discrete action spaces, and with the maximum entropy mechanism, policy exploration is encouraged to improve the global optimization capability. Second, the trained policy can swiftly adapt the subsequent well placement scheme for a specific state of the target reservoir without the requirement to initiate training from scratch, which can realize the offline application of the trained policy and has better real-time adjustability. To verify the effectiveness of the proposed method, it is tested in 2D and 3D reservoir models. The results show that DSAC not only outperforms the gradient-based optimization method, classical evolutionary algorithms, and existing reinforcement learning proximal policy optimization (PPO) method in terms of global optimization ability but also shows better real-time adjustability of the trained policy when applied offline.

Accuracy analysis of robotic-assisted immediate implant placement: A retrospective case series

ObjectivesThis study aimed to investigate the accuracy of a robotic computer-assisted implant surgery (r-CAIS) for immediate implant placement. MethodsPatients requiring immediate implant placement in the maxillary anterior region were enrolled for r-CAIS. Before surgery, the patients underwent a cone beam computed tomography (CBCT) scan with a positioning marker. Virtual implant placement position and drilling sequences were planned. Following spatial registration and calibration, the implants were placed with the robotic system under supervision. A postoperative CBCT was taken to control the actual implant positions. The DICOM data of the virtually planned and the actually placed implant were superimposed and registered through the accuracy verification software of the robotic system. The accuracy was calculated automatically. The deviation at the mesial–distal, labial–palatal, and apico-coronal directions were recorded. ResultsFifteen patients with 20 implants were included. No adverse surgical events or postoperative complications were reported. The global platform, apex, and angular deviation were 0.75 ± 0.20 mm (95 % CI: 0.65 to 0.84 mm), 0.70 ± 0.27 mm (95 % CI: 0.57 to 0.82 mm), and 1.17 ± 0.73° (95 % CI: 0.83 to 1.51°), respectively. Moreover, the vertical platform and apex deviation were 0.50 ± 0.31 mm, (95 % CI: 0.35 to 0.64 mm) and 0.48 ± 0.32 mm, (95 % CI: 0.33 to 0.63 mm), respectively. All the placed implant positions were further labial and apical than the planned ones, respectively. ConclusionsHigh accuracy of immediate implant placement was achieved with the robotic system. Clinical significanceOur study provided evidence to support the potential of the robotic system in implant placement, even in challenging scenarios.

Measurement of Implant Insertion Torque in Intentionally Undersized Osteotomy Site Preparation in the Posterior Maxilla: A Prospective Clinical Study.

Achieving adequate primary stability for dental implants in the posterior maxilla is challenging due to the area's low bone density and fine trabecular bone. Low primary implant stability can compromise the long-term success of the implant. This study aims to evaluate the effect of intentionally undersized osteotomy sites on the insertion torque of implants placed in type 4 bone density in the posterior maxilla, regardless of the surgeon's tactile sense of the bone density. The conventional implant placement technique was performed in the posterior maxilla by intentionally omitting the last drill of the recommended drilling sequence protocol. The insertion torque was measured using an integrated surgical motor software. The study included 72 implants in patients of both genders and different age groups. The retrieved samples were divided into four groups, with insertion torque ranging from 11 Ncm to 48 Ncm. The mean insertion torque was 26.51 ± 0.18 Ncm for all cases (P = .001). No significant difference was found in the mean insertion torque between different age groups (26.51 ± 2.845, P = .84). However, a significant difference was observed between male and female cases (P = .84). Most implant insertion torque measurements vary significantly between cases in the intentionally underprepared posterior maxillary osteotomy site. The last drill should be omitted for all preparations of the posterior maxillary implant sites. Intentionally minimizing the osteotomy site is recommended for all posterior maxillary implant cases.

Augmented reality in implantology: Virtual surgical checklist and augmented implant placement

ObjectivesAim of the present study was to create a pedagogical checklist for implant surgical protocol with an augmented reality (AR) guided freehand surgery to inexperienced surgeons using a head mounted display (HMD) with tracking. MethodsThe anatomical model of a patient with two missing mandibular teeth requiring conventional single-tooth implants was selected. The computed tomography (CT) scans were extracted and imported into segmentation and implant planning software. A Patient-specific dental splint through an intermediate strut, supported 3D-printed QR code. A checklist was generated to guide surgical procedure. After tracking, the AR-HMD projects the virtual pre-surgical plan (inferior alveolar nerve (IAN), implant axis, implant location) onto the real 3D-printed anatomical models. The entire drilling sequence was based on the manufacturer's recommendations, on 3D-printed anatomical models. After the implant surgical procedure, CT of the 3D-printed models was performed to compare the actual and simulated implant placements. All procedures in the study were performed in accordance with the Declaration of Helsinki. ResultsIn total, two implants were placed in a 3D-printed anatomical model of a female patient who required implant rehabilitation for dental agenesis at the second mandibular premolar positions (#35 and #45). Superimposition of the actual and simulated implants showed high concordance between them. ConclusionAR in education offers crucial surgical information for novice surgeons in real time. However, the benefits provided by AR in clinical and educational implantology must be demonstrated in other studies involving a larger number of patients, surgeons and apprentices.

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

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

Investigation of field scenarios using a 4n degrees of freedom transient torque and drag model

A coupled drill string dynamics model presents an opportunity to understand, replicate and potentially control the vibrations occurring along a drill string in a deep well. This paper describes a 4n degrees of freedom (4nDOF) model of the axial, torsional and lateral dynamics, consisting of coupled wave equations and lumped elements, which include modeling of the contact between the drill string and wellbore with a stiff string assumption. The model accounts for the bit-rock interaction, structural damping, and hydraulic forces acting on the lumped elements. The 4nDOF model is compared with three field scenarios from a drilling operation in the North Sea: a three-stage top drive start-up procedure, a drilling sequence starting from off-bottom conditions, and a backreaming operation at low rotational speed. The selected cases include instances of stick–slip and higher modes of torsional vibrations, which persist despite the use of a surface vibration mitigation system. High-frequency data recorded by a downhole measurement sub placed near the drill bit are used to verify the simulated downhole rotational speed and triaxial accelerations. The model is useful for analyzing torsional stick–slip events, which are replicated with a similar period and amplitude as in the downhole measurements. Furthermore, the model accurately reproduces the transition between first and second mode torsional oscillations upon the activation of a tuned top drive vibration mitigation system. The model can also be used to analyze lateral deformations and whirling of the drill string at various depths. The field case simulations show that the lateral dynamics can undergo significant changes at certain points in the drill string during torsional stick–slip and higher-mode torsional oscillations. The proposed model can be used to run simulations in close to real-time on a standard personal workstation, thus making it a valuable tool for devising and testing new drill string vibration mitigation solutions.

Positional accuracy during the sequence of static computer-assisted implant surgery in three alveolar ridge morphologies: An in vitro study.

This in vitro study aimed to assess the positional accuracy during the sequence of static computer-assisted implant surgery (sCAIS) according to the anatomical characteristics of the alveolar ridge. Maxillary bone models with six single tooth gaps including clinical scenarios of healed alveolar ridge (HR), single-rooted (SRS), and three-rooted socket (TRS) morphologies were used in this study. Positional deviations during implant placement procedures were evaluated after the pilot osteotomy (PD), final osteotomy (FD), and implant placement with respect to the pre-planned implant position by using a software package. ANOVA and post hoc analyses were performed. A total of 90 implants were included in this study. Higher mean angular, crestal, and apical deviations were found after the PD and FD (3.5 ± 2.4°, 0.7 ± 0.3mm, and 1.4 ± 0.8mm versus 3.6 ±2.2°, 0.6 ± 0.3mm, and 1.2 ± 0.6mm) compared to IP (2.8 ± 1.6°, 0.7 ± 0.3mm, and 1.2 ± 0.5mm, p ≤ 0.004). Implants placed in TRS demonstrated higher mean angular, crestal, and apical deviations (4.0 ± 1.7°, 0.8 ± 0.3mm, and 1.6 ± 0.5mm) compared to implants placed in SRS (2.5 ± 1.2°, 0.7 ± 0.3mm, and 1.1 ± 0.4mm) or HR (2.0 ± 0.9°, 0.5 ± 0.3mm, and 0.8 ± 0.4mm, p < 0.001). Positional deviations during sCAIS procedures are initiated with the first implant osteotomy and persist throughout the drilling sequence. However, deviations slightly decreased after implant placement. The alveolar ridge morphology is strongly associated with positional deviations. Higher deviations were observed in three-rooted and single-rooted sockets simulating an immediate approach compared to healed sites simulating a delayed protocol.

Site selection in Switzerland: parallelization of implementer data collection and technical–political decision-making

Abstract. The ambition of the Swiss radioactive waste program is to store waste at the best-suited, safest site in Switzerland. In September 2022 the announcement of Nördlich Lägern as the best-suited site was a major milestone of this site selection process. The full documentation of the site selection and the safety assessment will be submitted with the general license application at the end of 2024. The total time of the site selection process from its formal initiation in 2008 until submission of the general license application will be 16 years. The three-phase site selection process consisted of (1) initial screening, (2) de-selection of less favourable sites and (3) identification of the best-suited region. The database was refined for each selection step, but detailed site characterization was restricted to the final phase. The selection criteria were kept unchanged in the entire process. Four groups were used: (1) properties of the host rock; (2) long-term evolution of the geological situation; (3) quality of the geological findings; (4) engineering feasibility. The requirements for the criteria were re-adjusted in each phase to honour the available data and to adopt the requirements to the increasing quality of the sites as less-suited regions were continuously screened out. Initial estimates for the duration of the site selection were in the range of 8–10 years. Soon it became clear that the technical work and the decision-making process for each phase would take additional time. To minimize phases of low activity, NAGRA started data collection campaigns for each step as soon as possible. This led to overlapping of regulator reviews and decision-making by the government for the previous step and data collection by NAGRA for the next step. Step-1 data collection started as soon as enough information about the process was available. This allowed the proposal of the initial selection of sites a few months later. Data collection for step 2 with seismic data reprocessing, outcrop work, investigations of third-party boreholes, regional seismic and geodetic monitoring and 2D fill-in lines began in 2009/10, well before the decision on step 1 by the federal government in 2011. This overlap allowed the proposal for the detailed sited investigations in 2014 to be prepared. Step 3 data collection with 3D seismic campaigns started in 2015. To minimize the delay between the 3D seismic investigations and the start of deep drillings, drill sites were planned on available 2D seismic information. In 2017 initial 3D seismic data became available, the drilling sequence was adopted accordingly and the first applications for the drill sites were handed in. The licensing of the drill sites was continuously adjusted together with the involved authorities. The decision of the federal government on completion of the second phase, confirming three sites for the third and last phase, was taken in 2018. The data collection in the third and final step was completed with the ninth deep borehole in early 2022. Close monitoring of the incoming data allowed the announcement of the best-suited site in September of the same year.

Laser machining of free-standing silicon nitride membranes

Patterning free-standing Silicon Nitride membranes has enabled the development of various SiN-based devices such as quantum resonators, biosensors, temperature detectors, and plasmonic devices. Patterning SiN membranes usually involves expensive and time-consuming cleanroom techniques that limit flexibility in the development of new SiN membrane designs. While ultrafast laser machining has been proposed to create micron to submicron features in these membranes, laser machining of large area features has not been reported as it often results in membrane failure due to stress concentration during laser machining. We show that continuous laser machining can be used to create a crack and to extract the fracture toughness of the membrane (1.9 ± 0.3 MPa.m1/2). To successfully patterned SiN membranes without failure, a low stress laser machining method is developed, where stress concentration can be minimized by adjusting the laser drilling sequence, a result confirmed by finite element simulations. Complex shapes can thus be machined over a large area with a very high success rate. Laser parameters are optimized to improve the quality of the laser-cut edges without the formation of laser-induced periodic surface structure. Transmission Electron Microscopy and Electron Energy Loss Spectroscopy indicate a modification of the Si/N ratio over a small region next to the laser machined features. These results demonstrate that low stress ultrafast laser machining can be used to create patterns in SiN membranes quickly and economically, enabling the rapid development of new membrane designs.

Drilling Sequence Optimization Using Evolutionary Algorithms to Reduce Heat Accumulation for Femtosecond Laser Drilling with Multi-Spot Beam Profiles.

We report on laser drilling borehole arrays using ultrashort pulsed lasers with a particular focus on reducing the inadvertent heat accumulation across the workpiece by optimizing the drilling sequence. For the optimization, evolutionary algorithms are used and their results are verified by thermal simulation using Comsol and experimentally evaluated using a thermal imaging camera. To enhance process efficiency in terms of boreholes drilled per second, multi-spot approaches are employed using a spatial light modulator. However, as higher temperatures occur across the workpiece when using simultaneous multi-spot drilling as compared to a single-spot process, a subtle spatial distribution and sequence of the multi-spot approach has to be selected in order to limit the resulting local heat input over the processing time. Different optimization approaches based on evolutionary algorithms aid to select those drilling sequences which allow for the combination of a high efficiency of multi-spot profiles, a low-generated process temperature and a high-component quality. In particular, using a 4 × 4 laser spot array allows for the drilling of 40,000 boreholes in less than 76 s (526 boreholes/s) with a reduced temperature increase by about 35%, as compared to a single spot process when employing an optimized drilling sequence.

Drilling Path Planning of Rock-Drilling Jumbo Using a Vehicle-Mounted 3D Scanner

Achieving intelligent rock excavation is an important development direction in underground engineering construction. Currently, some rock-drilling jumbos are able to perform autonomous operations under ideal contour surfaces. However, irregular contour surfaces resulting from factors such as rock characteristics, drilling deviation, and blasting effects present a significant challenge for automated drilling under non-ideal surfaces, which constrains the intelligentization of rock excavation. To address this issue, this paper proposes a method for extracting contour surfaces and planning drilling paths based on a vehicle-mounted 3D scanner. This method effectively extracts contour surfaces and optimizes drilling paths, thereby improving work efficiency and safety. Specifically, the proposed method includes: (i) the real-time scanning of cross-sectional contours using a vehicle-mounted 3D scanner to construct an accurate three-dimensional point-cloud model and obtain contour over-digging information; the acquired data are compared with theoretical drilling maps in the vehicle’s coordinate system to re-plan the blasting-hole point set; (ii) the development of a volume-based dynamic search algorithm based on the irregularities of contour surfaces to detect potential collisions between holes; and (iii) the conversion of the drilling sequence planning based on the new blasting hole point set into a traveling salesman problem (TSP), and optimization using a Hybrid Greedy Genetic Algorithm (HGGA) to achieve path traversal of all drilling positions. The effectiveness of the proposed method was verified using rock excavation in a certain mine as an example. The results show that the overall recognition rate of the contour over-digging reached over 80%, the number of arm collisions was significantly reduced, and the distance traveled by the drilling rig was reduced by 35% using the improved genetic algorithm-based rock-drilling rig path planning.

Influence of drilling sequence and guide-hole design on the accuracy of static computer-assisted implant surgery in extraction sockets and healed sites-An in vitro investigation.

To evaluate the effect of drilling sequence, guide-hole design, and alveolar ridge morphology on the accuracy of implant placement via static computer-assisted implant surgery (sCAIS). Standardized maxillary bone models including single-tooth gaps with fresh extraction sockets or healed alveolar ridge morphologies were evaluated in this study. Implants were placed using different drilling sequences (i.e., complete [CDS] or minimum [MDS]), and guide-hole designs (i.e., manufacturer's sleeve [MS] or sleeveless [SL] guide-hole designs). The time for implant placement via sCAIS procedures was also recorded. The angular, crestal, and apical three-dimensional deviations between planned and final implant positions were digitally obtained. Statistical analyses were conducted by a non-parametric three-way ANOVA (α= .05). Based on a sample size analysis, a total of 72 implants were included in this study. Significantly higher implant position accuracy was found at healed sites compared to extraction sockets and in SL compared to MS guide-hole design in angular, crestal, and apical 3D deviations (p≤ .048). A tendency for higher accuracy was observed for the CDS compared to the MDS, although the effect was not statistically significant (p= .09). The MDS required significantly shorter preparation times compared with CDS (p< .0001). Implant placement via sCAIS resulted in higher accuracy in healed sites than extraction sockets, when using SL compared to MS guides, and tended to be more accurate when using CDS compared to MDS. Therefore, even though surgery time was shorter with MDS, its use should be limited to strictly selected cases.

Dynamic Navigation: A Novel Tool for Dental Implant Surgery

Dynamic navigation is an advanced technology that has revolutionized dental implant surgeries. Before being used in implant dentistry, navigation technique has been practiced in neurosurgery for performing minimally invasive brain surgeries. Navigation surgery for implant placement can be broadly categorized as dynamic and static navigation. The static navigation uses a static surgical guide for the sequential drilling of the osteotomy site and the implant placement. The static navigation can either be fully guided or partial/half-guided. Dynamic navigation is a computer-assisted implant placement technique that uses real-time imaging to guide the implant placement procedure. In dynamic navigation, three-dimensional (3D) software monitors and tracks the bone drilling and implant placement in real-time during the entire procedure. This technique involves prosthetically driven virtual implant placement planning with Cone Beam Computed Tomography (CBCT) before the implant surgery. The 3D image of the patient is analyzed in a CBCT scan. This image is then used to plan the placement of the implant and create a surgical guide. A resin guided template is 3D printed or milled which is used during the surgery. The CBCT scan images are transferred into a 3D virtual image using digital software, which allows 3D viewing of the structures using Computer Aided Design (CAD). A calibrated special navigation instrument with specific software guides the bone drilling sequence and the implant placement. The drilling procedure is completely tracked and the patient’s anatomy and the surgical procedures in real time is shown in a 3D software. The use of real-time imaging and computer-aided technology ensures that the implant is placed precisely in the desired location, reducing the risks associated with conventional implant placement. Dynamic navigation is an effective and precise method that allows for more accurate placement of dental implants, which reduces the chance of damaging anatomical structures. It also gives clinicians the possibility to modify the planned surgical approach during the surgery. Additionally, because the implant is placed more accurately, there is less risk of implant failure. However, a learning curve and a training period are required before one masters this novel technology. Dynamic navigation can potentially become a preferred method for dental implant placement in the near future.

Непосредственные изменения пульсового кровенаполнения в суставных концах подвздошной и бедренной костей после их туннелирования при болезни Пертеса

Introduction In Perthes disease of stage 1 to 2, intraosseous pressure (IOP) of the tissue fluid in the head of the femur due to disorders of the venous outflow increases, the microvasculature is compressed and pulse blood supply is limited. To eliminate secondary circulatory insufficiency, the proximal femur and the supra-acetabular region of the ilium were perforated with wires, and differences in the pulse wave of blood filling in the femoral head associated with the order of perforation of the articular ends of the bones were revealed. Purpose To determine the dependence of the pulse wave of blood filling in the femoral head on the sequence of drilling of the supra-acetabular region of the ilium and the proximal femur in patients with Perthes disease. Material and methods A pulse wave of blood filling in the intraosseous tissues was recorded in 47 patients, aged 6-9 years, using rheovasography. In 6 patients, the supra-acetabular region of the ilium was perforated, then the proximal femur; in 41 patients the sequence was vice versa. Results In the hip joint, perforation of the articular end of one bone leads to post-traumatic angiospasm in the articular ends of both bones, and pulse blood supply decreases. However, by the initial perforation of the proximal end of the femur, the pulse blood supply to the tissues of the femoral head increases, and subsequent drilling of the supra-acetabular region of the ilium contributes to its additional increase. Taking into account the initially increased IOP in the femoral head, it was concluded that perforation leads to decompression of its microcirculatory bed, and pulse blood filling increases, and post-traumatic angiospasm does not develop. Conclusion In Perthes disease, the femoral head should be drilled first to decompress its microvasculature, then the supra-acetabular region of the ilium to redistribute blood circulation and further increase blood flow to the femoral head.

Optimization of Heat Accumulation during Femtosecond Laser Drilling Borehole Matrices by Using a Simplex Algorithm.

We report on an optimization study of percussion drilling thin metal sheets employing a high repetition rate, high power femtosecond laser with respect to the resulting heat accumulation. A specified simplex algorithm was employed to optimize the spatial drilling sequence, whereas a simplified thermal simulation using COMSOL was validated by comparing its results to the temperature measurements using an infrared camera. Optimization for drilling borehole matrices was aspired with respect to the generated temperature across the processed specimen, while the drilling strategy was altered in its spatial drilling sequence and by using multi-spot approaches generated by a spatial light modulator. As a result, we found that an optimization strategy based on limited consecutive holes in a Moore neighborhood led to reduced temperatures and the shortest process times.

A novel Snap-FIT implant surgical guide design: a case report

To clinically evaluate the precision of a novel tooth-supported snap-FIT surgical guide (SF), inspired by the removable dentures clasp principle. Two patients with a single missing tooth underwent CBCT and optical scans, that were superimposed for implant virtual planning (BlueSkyBio, USA). A novel SF implant surgical guide for each case was designed and 3D printed (offset from the surface 0.07 mm, material thickness 2.3 mm, selective undercuts allowed). Under local anesthesia, a full-thickness flap was elevated and SF positioned. Drill sequence was partially guided, with profiling, taping of implant bed, and implant placement done free-hand. One narrow (NC) and one regular diameter (RC) bone-level implants were placed (Straumann, CH). Further, 5-0 non-resorbable sutures were used for wound closure. The duration of surgery was 24 min and 27 min, respectively. Healing was uneventful in both cases. After 4 months, implants were uncovered and implant position recorded with the intraoral scanner. Source files and the scanned data were aligned (error: 0.05 mm/0.02 mm, GOM inspect, Germany). A novel implant accuracy evaluation method was developed. The apical and neck point of the implant was determined as an intersection point of a plane and cylinder, generated from the scan body (Gaussian best-fit). Implant placement error at the implant neck was 0.67 mm/0.3 mm, at the apex 1.02 mm/0.32 mm and the angle deviation 3.28°/3.33° for NC and RC implant, respectively. The novel SF surgical guide is feasible with a simple modification of classical guide design, without requiring additional materials, devices, or procedures. It demonstrates high implant placement accuracy, similar to the fully guided protocol.

Case Report: Combining Molar Interradicular Osteotomy With Immediate Implant Placement: A Three-Year Case-Series Study

Background: Immediate implant placement in the area of multirooted molars includes many anatomical challenges, particularly with osteotomy preparation in the interradicular bone.Methods: In this article, we are reporting ten cases in which implant beds were prepared before root extraction. After coronectomy, pre-extractive interradicular implant bed preparations were performed through the retained root complexes. A dimple in the roof of the furcation was created using a no. 8 round surgical bur. The osteotomies were then completed through the tooth’s initially retained root complex in the regular sequence of drilling. Before implant placement, the remaining root segments were removed. The retained root parts guided the osteotomy drills and allowed for precise positioning and angulation of the implant bed preparation with respect to the emergence profile of the tooth.Results: Data from a 3-year follow-up of the crestal bone showed good bone levels in relation to the implant platform.Conclusion: The technique described permitted accurate implant placement in the prepared osteotomy, thus enabling immediate implant positioning in multirooted extraction sites.

Temperature Changes during Implant Osteotomy Preparations in Fresh Human Cadaver Tibiae, Comparing Straight with Tapered Drills.

The success of osseointegration depends on many factors. With temperatures beyond a 47 °C threshold over 1 min, bone survival may be impaired. The purpose of the study was to evaluate, in fresh human cadaver tibiae, the temperature changes during osteotomy preparations using two straight and two tapered implant systems’ drills, external irrigation, and varying revolutions per minute (RPM). The tibiae from a fresh female cadaver were harvested bilaterally. Two tapered and two straight design drills were assessed. Two-hundred and forty osteotomies were prepared at 6 mm depth following the drill sequence of the manufacturers’ protocol for each drilling speed. Difference in temperature (ΔΤ) was calculated by subtracting the baseline from the maximum temperature (ΔT = Tmax − Tbase). Drill design and drill diameter, as independent variables or synergistically, had a significant effect on ΔΤ. Tapered drills: As the drill diameter increased, ΔΤ increased at all RPM. Straight drills: As the drill diameter increased, ΔΤ remained constant or slightly decreased at all RPM. Drill diameter and design had a significant effect on ΔΤ in human tibiae, which never exceeded the critical threshold of 47 °C. Tapered drills caused significantly greater heat production compared to straight drills.

Ex vivo Evaluation of a New Drill System for Placement of Percutaneous Bone Conduction Devices.

The procedure for installation of a percutaneous bone-conducting device has undergone significant improvements since its introduction 40 years ago. Today, the linear incision technique with tissue preservation (LITT-P) and the minimally invasive procedure (MIPS) are the most commonly used approaches. In both these techniques, a gradual increase of the osteotomy using a three-step drilling sequence is utilized, as this approach can allow a stepwise deepening and widening of the osteotomy in the mastoid and can prevent bone overheating. A new minimally invasive procedure (MONO) has been developed that allows an osteotomy to be performed and enables complete removal of the bone volume in one single drill step for a 4 mm implant using a novel parabolic twist drill. Here, the feasibility of the MONO procedure was qualitatively and quantitatively evaluated in terms of the dura response to drill trauma in comparison with the outcomes achieved with guide drills used for the LITT-P and MIPS techniques. Fresh frozen temporal bone from a human cadaver was subjected to penetration by three drills beyond the base of the mastoid bone to different depths. The sites were evaluated, and the damage to and possible penetration of the dura were determined. The results showed that for a drill depth exceeding mastoid bone thickness by not more than 1 mm, damage to the dura was limited or nonexistent, whereas for a drill depth exceeding bone thickness by 2 mm, damage increased, or the dura was penetrated. There was a trend toward more damage and penetration for both the round burr and MIPS guide drill compared with the MONO drill bit. From this experimental ex vivo study, it can be concluded that if the dura is encountered, the MONO system is not more inclined to penetrate the dura than the conventional LITT-P and MIPS systems.