Search Results (406)

To address the issues of large errors, low accuracy, and time-consuming simulations in finite element (FE) models of tapping processes, which hinder the identification of optimal structural parameters, this study integrates FE simulation with experimental testing to optimize the structural parameters of spiral taps specifically designed for stainless steel. Initially, single-factor experiments were conducted to analyze the influence of mesh parameters on experimental outcomes, leading to the identification of optimal mesh coefficients. Subsequently, the accuracy of the FE tapping simulation model was validated by comparing trends in axial force, torque, and chip morphology between simulations and actual tapping experiments. Orthogonal experimental design combined with entropy weight analysis and range analysis was then employed to conduct FE simulations. The results indicated that the optimal structural parameter combination is a helix angle of 43°, cone angle of 19°, and cutting edge relief amount of 0.18 mm. Finally, based on this combination, optimized spiral taps were manufactured and subjected to comparative performance testing. The results demonstrated significant improvements: the average maximum axial force decreased by 33.22%, average maximum torque decreased by 13.41%, average axial force decreased by 38.22%, and average torque decreased by 24.87%. Error analysis comparing corrected simulation results with actual tapping tests revealed axial force and torque error rates of 5.04% and 0.24%, respectively. Full article

Background: The Da Silva Cone procedure for Ebstein anomaly has dramatically improved tricuspid valve competence and clinical outcomes. However, preoperative left ventricular (LV) dysfunction and immediate postoperative right ventricular (RV) systolic dysfunction are frequently observed. While excellent valve outcomes are well established, recovery of biventricular function following the Cone remains less defined. This study aimed to evaluate longitudinal changes in RV and LV function postoperatively and over a minimum of six months post-Cone operation. Methods: A single center retrospective review of 134 patients who underwent Cone repair for Ebstein’s anomaly from 2016 to 2024 was performed. Echocardiograms were analyzed at three time points: preoperative (Time 1), hospital discharge (Time 2), and ≥6 months postoperative (Time 3). RV parameters included fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), and tricuspid S′. LV parameters included left ventricular ejection fraction (LVEF), end-diastolic volume indexed to body surface area (LVEDVi), left ventricular stroke volume (LVSVi), and mitral E/E′. Subgroup analyses examined outcomes by prior Glenn, Starnes procedure, and degree of RV dilation. Paired two sample t-tests were used to compare serial measures. Results: Median age at surgery was 7.8 years (IQR: 2.3–17.7). All patients had discharge echocardiograms; 70 had follow-up studies at ≥6 months. RV function declined postoperatively with reductions in FAC (35% to 21%), TAPSE (2.0 to 0.8 cm), and S′ (13 to 5 cm/s), all p < 0.001. By Time 3, these measures improved (FAC to 29%, TAPSE to 1.3 cm, S′ to 7 cm/s) but did not fully return to baseline. LVEDVi and LVSVi increased significantly by Time 3 (LVEDVi: 47 to 54 mL/m²; LVSVi: 30 to 34 mL/m²; p < 0.001), while LVEF remained unchanged. Patients with prior Glenn or Starnes had greater Time 1 LV volumes and lower RV function, but by Time 3, most differences resolved. Moderate–severe preoperative RV dilation was associated with worse RV function at Time 2 and normalized by Time 3. Conclusions: The Da Silva Cone procedure leads to early postoperative RV dysfunction with partial recovery over the mid-term follow-up. Concurrently, LV filling and stroke volume improve, reflecting favorable interventricular interaction. These findings support echocardiographic surveillance to guide functional recovery post-Cone and inform patient counseling. Full article

Background: MRA is used in our center for monitoring post-treatment residual aneurysmal neck and stent patency. IV CBCT offers better spatial resolution and may provide significant advantages. Objective: This study investigates the image quality of IV CBCT compared to that of MRA for the follow-up of intracranial aneurysms. Materials and Methods: In this prospective cohort study, 97 patients (mean age: 63.1 ± 11.7; 75 women and 22 men) with 114 treated cerebral aneurysms were included from July 2023 to April 2024. All patients underwent IV CBCT and MRA on the same day. Two neurointerventional radiologists assessed image quality using a five-point Likert scale on two separate occasions six weeks apart. Diagnostic values were evaluated across six parameters. Intra-observer and inter-observer agreements were calculated. Subgroup analyses were performed. Results: Overall, IV CBCT and MRA are comparable in terms of their ability to assess parent vessel status and the degree of artifacts (p > 0.05) though MRA shows a slight advantage in evaluating residual aneurysmal neck (p = 0.05). For clipped aneurysms, IV CBCT is superior in assessing residual aneurysmal neck (OR = 16.0, p < 0.001) and parent vessel status (OR = 15.1, p < 0.001) with significantly fewer artifacts (OR > 100, p < 0.001). For aneurysms solely treated with stents, IV CBCT is superior in assessing residual aneurysmal neck (OR > 20, p = 0.002) and parent vessel status (OR > 20, p = 0.002) with significantly fewer artifacts (OR > 20, p = 0.002). IV CBCT outperforms MRA in evaluating stent struts and the vessel wall status of a stented segment when MRA is non-diagnostic. Conclusions: IV CBCT and MRA have their own strengths and roles in the follow-up of post-treatment intracranial aneurysms. Overall, IV CBCT is superior in terms of its assessment of intracranial aneurysms treated solely with stents or surgical clips. Full article

To address the challenges of water coning and early water breakthrough commonly encountered during the development of bottom-water gas reservoirs, this study establishes a fully coupled numerical simulation model integrating a horizontal wellbore, inflow control device (ICD) screens, and a zonal water control system. A novel “dual inflow performance index” method is introduced for the first time, enabling separate calculation of the pressure drops induced by gas and water phases flowing through the ICDs, thereby improving the accuracy of pressure simulations throughout the production lifecycle. The model divides the entire production system into four physically distinct subsystems, the bottom-water gas reservoir, ICD screens, production compartments, and the horizontal wellbore, which are dynamically coupled through transient interflow exchange. Based on geological parameters from the SPE10 dataset, the model simulates realistic production scenarios. The results show that the proposed model accurately captures the time-dependent increase in ICD pressure drop as fluid properties evolve during production. Moreover, the zonal water control method outperforms the single ICD-based control strategy in water control performance, achieving a 23% reduction in cumulative water production. Additionally, the water control intensity of the ICD screens increases nonlinearly with the reduction in the number of openings. In highly heterogeneous reservoirs with significant permeability contrast, effective suppression of water coning can only be achieved by setting a minimal number of openings in the high-permeability compartments, resulting in up to a 15% reduction in cumulative water production. The timing of production compartment shutdown exerts a significant influence on water control performance. The optimal strategy is to first identify the water breakthrough point through unconstrained production simulation as production with all eight ICD screen openings fully open and then shut down the high-permeability production compartment around this critical time. This approach can suppress cumulative water production by up to 27%. Overall, the proposed model offers a practical and robust tool for optimizing completion design and water control strategies in complex bottom-water gas reservoirs. Full article

The new mineral achyrophanite (K,Na)₃(Fe³⁺,Ti,Al,Mg)₅O₂(AsO₄)₅ was found in high-temperature sublimates of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with aphthitalite-group sulfates, hematite, alluaudite-group arsenates (badalovite, calciojohillerite, johillerite, nickenichite, hatertite, and khrenovite), ozerovaite, pansnerite, arsenatrotitanite, yurmarinite, svabite, tilasite, katiarsite, yurgensonite, As-bearing sanidine, anhydrite, rutile, cassiterite, and pseudobrookite. Achyrophanite occurs as long-prismatic to acicular or, rarer, tabular crystals up to 0.02 × 0.2 × 1.5 mm, which form parallel, radiating, bush-like, or chaotic aggregates up to 3 mm across. It is transparent, straw-yellow to golden yellow, with strong vitreous luster. The mineral is brittle, with (001) perfect cleavage. D_calc is 3.814 g cm^–3. Achyrophanite is optically biaxial (+), α = 1.823(7), β = 1.840(7), γ = 1.895(7) (589 nm), 2V (meas.) = 60(10)°. Chemical composition (wt.%, electron microprobe) is: Na₂O 3.68, K₂O 9.32, CaO 0.38, MgO 1.37, MnO 0.08, CuO 0.82, ZnO 0.48, Al₂O₃ 2.09, Fe₂O₃ 20.42, SiO₂ 0.12, TiO₂ 7.35, P₂O₅ 0.14, V₂O₅ 0.33, As₂O₅ 51.88, SO₃ 1.04, and total 99.40. The empirical formula calculated based on 22 O apfu is Na_1.29K_2.15Ca_0.07Mg_0.34Mn_0.01Cu_0.11Zn_0.06Al_0.44Fe³⁺_2.77Ti_1.00Si_0.02P_0.02S_0.14V_0.04As_4.90O₂₂. Achyrophanite is orthorhombic, space group P222₁, a = 6.5824(2), b = 13.2488(4), c = 10.7613(3) Å, V = 938.48(5) ų and Z = 2. The strongest reflections of the PXRD pattern [d,Å(I)(hkl)] are 5.615(59)(101), 4.174(42)(022), 3.669(31)(130), 3.148(33)(103), 2.852(43)(141), 2.814(100)(042, 202), 2.689(29)(004), and 2.237(28)(152). The crystal structure of achyrophanite (solved from single-crystal XRD data, R = 4.47%) is unique. It is based on the octahedral-tetrahedral M-T-O pseudo-framework (M = Fe³⁺ with admixed Ti, Al, Mg, Na; T = As⁵⁺). Large-cation A sites (A = K, Na) are located in the channels of the pseudo-framework. The achyrophanite structure can be described as stuffed, with the defect heteropolyhedral pseudo-framework derivative of the orthorhombic Fe³⁺AsO₄ archetype. The mineral is named from the Greek άχυρον, straw, and φαίνομαι, to appear, in allusion to its typical straw-yellow color and long prismatic habit of crystals. Full article

In the zenith-horizon placement for achieving minimum geometric dilution of precision (GDOP), one access node or sensor is positioned along the z-axis, while the remaining nodes are placed symmetrically on a three-dimensional (3D) cone. This configuration yields the minimum GDOP at the cone’s tip, which we term the designated min-GDOP point. However, in practical localization applications, the unknown node is not necessarily located at this designated min-GDOP point; instead, it may be situated anywhere within an area. As a result, evaluating localization accuracy across the entire area, rather than at a single point, is more relevant. Averaged horizontal dilution of precision (HDOP) and GDOP across the region provide more meaningful metrics for system-wide performance than values computed only at a specific location. Although many recent positioning applications leverage multiple unmanned aerial vehicles (UAVs), many established fixed sensor deployments predate the widespread adoption of UAVs. This paper proposes a novel approach with a single UAV working in conjunction with existing fixed access nodes for positioning. This approach offers improved adaptability for fixed infrastructure while circumventing the expense of establishing entirely new UAV systems, thus providing a valuable compromise. We investigate the criteria of average HDOP and GDOP over the given area. The objective is to determine optimal UAV positions along the flight path that minimize the average HDOP and/or GDOP across the area. Due to the analytical complexity, we employ numerical methods. Our simulation results demonstrate that minimizing average HDOP and GDOP often requires different UAV positions, depending on the number of access nodes and the size of the area. Consequently, achieving simultaneous minimization of both metrics with a single UAV trajectory is generally infeasible. When minimizing the average HDOP with a small number of access nodes, aligning the UAV’s XY-plane angle with those of the stationary nodes, offset by ${60}^{\circ }$, proves advantageous. This angular alignment becomes less critical as the number of access nodes increases. For scenarios where both HDOP and GDOP are important, UAV placement can be optimized by selecting appropriate trade-offs. Additionally, we quantify how increasing the number of access nodes improves the average HDOP and GDOP over the specified area. Full article

Background/Objectives: This ex vivo study aimed to evaluate the diagnostic performance of ultra-low-dose (ULD) cone-beam computed tomography (CBCT) protocols in detecting vestibular bone defects for immediate implant planning, using intraoral scan (IOS) data as a reference. Methods: Four CBCT protocols (ENDO, A, B, C) were applied to four dried human skulls using a standardized setup and a single CBCT unit (Planmeca ProMax^® 3D Mid, Planmeca Oy, Helsinki, Finland). All scans were taken at 90 kV, with varying parameters: (1) ENDO (40 × 50 mm, 75 µm, 12 mA, 80–120 µSv, 15 s), (2) A (50 × 50 mm, 75 µm, 9 mA, 20–40 µSv, 5 s), (3) B (100 × 60 mm, 150 µm, 7.1 mA, 22–32 µSv, 5 s), and (4) C (100 × 100 mm, 200 µm, 7.1 mA, 44 µSv, 4 s). Vestibular root surfaces of single-rooted teeth (FDI regions 15–25 and 35–45) were digitized via IOS and exported as STL files. CBCT datasets were superimposed using 3D software (Blender 2.79), and surface defects were measured and compared using one-sample t-tests and Bland–Altman analysis. The level of significance was set at p < 0.05. Results: A total of 330 vestibular surfaces from 66 teeth were analyzed. Compared to the IOS reference, protocols ENDO and A showed minimal differences (p > 0.05). In contrast, protocols B and C exhibited statistically significant deviations (p < 0.05). Protocol B demonstrated a mean difference of −0.477 mm² with limits of agreement (LoA) from −2.04 to 1.09 mm² and significant intra-rater variability (p < 0.05). Protocol C revealed a similar mean deviation (−0.455 mm²) but a wider LoA (−2.72 to 1.81 mm²), indicating greater measurement variability. Overall, larger voxel sizes were associated with increased random error, although deviations remained within clinically acceptable limits. Conclusions: Despite statistical significance, deviations for protocols B and C remained within clinically acceptable limits. ULD CBCT protocols are, thus, suitable for evaluating vestibular bone defects with reduced radiation exposure. Full article

The aim of this study is to evaluate the apical sealing ability of novel bioceramic-based (BCB) and widely used resin-based (RB) root canal sealers in combination with traditional or bioceramic-coated gutta-percha points. A total of 92 human single-root extracted teeth were endodontically treated and divided into three groups (A, B, and C) of 30 samples based on the endodontic sealer/type of gutta-percha points/obturation method used. One tooth sample was used for the negative and positive controls (each). Group A: BCB sealer BioRoot RCS (Septodont, Saint-Maur-des-Fossés, France)/bioceramic-impregnated gutta-percha TotalFill BC points (FKG Dentaire, La Chaux-de-Fonds, Switzerland)/cold hydraulic single-cone. Group B: BioRoot RCS (Septodont, France)/traditional Protaper Gold Gutta-Percha Points (Dentsply Sirona, Charlotte, NC, USA)/cold hydraulic single-cone. Group C: RB sealer AdSeal (Meta Biomed, Cheongju, Republic of Korea)/traditional Protaper Gold Gutta-Percha Points (Dentsply Sirona, USA)/warm vertical condensation. A dye penetration method was applied, and the length of apicocoronal penetration was measured using a surgical microscope. The data were statistically analyzed to evaluate differences at the 0.05 significance level. A significant difference was found between groups A and C, p = 0.0003, and groups B and C, p = 0.003. The data analysis proved that the BCB sealer using the cold hydraulic single-cone method ensured a substantially better seal than the RB sealer using the warm vertical condensation method. The choice of the type of gutta-percha points (bioceramic-coated or regular) appeared to be unimportant. No statistical significance was found between groups A and B, which indicates that using bioceramic-coated gutta-percha points does not bring any considerable benefit in view of a no-gap root canal obturation. Full article

Background: Tooth extractions commonly result in dimensional changes of the alveolar ridge. Platelet-rich fibrin (PRF) has emerged as a promising autologous biomaterial for alveolar preservation. This randomized controlled trial aimed to evaluate, through cone beam computed tomography (CBCT), the effect of PRF in maintaining alveolar dimensions post-extraction. Methods: A single-blind, randomized controlled clinical trial was conducted in 10 systemically healthy patients requiring premolar extractions for orthodontic reasons. A total of 36 alveoli were analyzed: 19 with PRF (experimental group) and 17 without PRF (control group). CBCT scans were performed at baseline, 30 days, and 120 days post-extraction to measure alveolar height, vestibulo-palatal/lingual depth at 1, 3, and 5 mm, and bone tissue density using Hounsfield Units (HU). Results: Baseline cephalocaudal alveolar height was similar in both groups (~10.5 mm, p = 0.399). At 30 days, height preservation was significantly greater in the PRF group (10.61 mm vs. 8.82 mm, p < 0.001). At 120 days, the PRF group maintained greater height (10.30 mm vs. 9.31 mm), although this difference was not statistically significant (p = 0.059). No significant differences were observed in alveolar depth at 1, 3, or 5 mm (p > 0.05). The PRF group showed a trend toward better preservation and higher mean bone density values (190–282 HU), although no formal statistical comparison of HU values was performed. Repeated measures ANOVA revealed a significant interaction effect of time and group on alveolar height (p = 0.010, η² = 0.046) and at 1 mm depth (p = 0.035, η² = 0.020). Conclusions: PRF significantly improved short-term alveolar height preservation. Trends toward better depth preservation and higher bone density values were observed in the PRF group, although these findings were not statistically significant. PRF appears to be a safe biomaterial with potential to support alveolar ridge maintenance post-extraction. Full article

This study aimed to evaluate mandibular fixation techniques using monocortical plates following sagittal split ramus osteotomy in skeletal Class III patients. Ninety-three patients were categorized into three groups based on fixation methods: four-hole miniplate with one proximal and two distal screws (Group 1); four-hole miniplate with four screws (Group 2); sliding plate with two proximal and one distal screws (Group 3). Cone-beam computed tomography scans were obtained at three time points: immediately postoperative (T1), 6 months (T2), and 12 months (T3). The yaw, roll, and pitch rotations of the proximal segment, as well as horizontal and vertical changes of the pogonion, were evaluated. Group 1 exhibited significantly greater counterclockwise rotation of the proximal segments at T2 (p = 0.021) and T3 (p = 0.035) compared to the other groups. Additionally, Group 1 showed significantly smaller anterior and superior displacement of the pogonion at T3 (0.97 ± 2.10 mm, p = 0.009; 0.03 ± 1.62 mm, p = 0.011, respectively). Following surgical wafer removal, intimate occlusal contact is archived and the elimination of premature contacts through postoperative orthodontic treatment contributes to counterclockwise autorotation of the mandible. Therefore, anterior and superior movements of the pogonion are expected if firm fixation between the proximal and distal segments is achieved. Therefore, these findings suggest that a single proximal screw, as seen in a three-screw fixation, may act as a fulcrum, insufficiently resisting postoperative clockwise rotation of the distal segments. Full article

This study evaluates the wear and corrosion resistance of the Cu-50Ni-5Al alloy reinforced with CeO₂ nanoparticles for potential use as anodes in molten carbonate fuel cells (MCFCs). Cu–50Ni–5Al alloys were synthesized, with and without the incorporation of 1% CeO₂ nanoparticles, by the mechanical alloying method and spark plasma sintering (SPS). The samples were evaluated using a single scratch test with a cone-spherical diamond indenter under progressive normal loading conditions. A non-contact 3D surface profiler characterized the scratched surfaces to support the analysis. Progressive loading tests indicated a reduction of up to 50% in COF with 1% NPs, with specific values drop-ping from 0.48 in the unreinforced alloy to 0.25 in the CeO₂-doped composite at 15 N of applied load. Furthermore, the introduction of CeO₂ decreased scratch depths by 25%, indicating enhanced wear resistance. The electrochemical behavior of the samples was evaluated by electrochemical impedance spectroscopy (EIS) in a molten carbonate medium under a H₂/N₂ atmosphere at 550 °C for 120 h. Subsequently, the corrosion products were characterized using X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the CeO₂-reinforced alloy exhibits superior electro-chemical stability in molten carbonate environments (Li₂CO₃-K₂CO₃) under an H₂/N₂ atmosphere at 550 °C for 120 h. A marked reduction in polarization resistance and a pronounced re-passivation effect were observed, suggesting enhanced anodic protection. This effect is attributed to the formation of aluminum and copper oxides in both compositions, together with the appearance of NiO as the predominant phase in the materials reinforced with nanoparticles in a hydrogen-reducing atmosphere. The addition of CeO₂ nanoparticles significantly improves wear resistance and corrosion performance. Recognizing this effect is vital for creating strategies to enhance the material’s durability in challenging environments like MCFC. Full article

Conus venoms are both highly powerful and complex, exhibiting a remarkably intriguing molecular variability. The biologic reasons behind such astonishing molecular diversity are yet to be fully understood. We hypothesized that the current knowledge has been hampered by a lack of studies targeting the whole Conus genus backed by a feeding habit analysis, as opposed to the abundant studies focused on single species or at the individual level. We aim to enlighten the understanding of the remarkable venom variability in cone snails while pushing to deliver novel peptides for biomedical applications through a broad transcriptomics approach. Here, we assessed 76 publicly available venom-related and unrelated transcriptomes from a total of 20 different Conus species. The shared transcriptomic repertoire revealed several gene variations in accordance with predatory diets (e.g., gene loss in piscivorous species), indicating that feeding habit largely influences venom evolution. Furthermore, evidences of ubiquitous symbiotic relationships within the venom organs were depicted, as biological processes alien to Conus species (e.g., Sorocarp morphogenesis) were found in all analyzed transcriptomes. Moreover, 88 potential anti-microbial peptides were bioinformatically detected, including one showing similarity with the human ACE2 receptor. Our study highlights the importance of in-depth comparative transcriptomic analyses, fostering cross-field synergic assessments by relying on informatic, biologic, and pharmacologic resources. Full article

Objectives: This study aimed to develop a semi-automated registration method for aligning preoperative non-contrast T2-weighted MRI with postoperative high-resolution cone-beam CT (DynaCT) in patients undergoing directional deep brain stimulation (dDBS) surgery targeting the subthalamic nucleus (STN). The aim was to facilitate image-guided programming of DBS devices and postoperative verification of the alignment of segmented contacts. Materials and Methods: A dataset of ten patients undergoing bilateral dDBS implantation was retrospectively collected, including DynaCT (acquired postoperatively) and non-contrast T2-weighted MRI (obtained preoperatively). A semi-automated registration method was used, employing manual initialization due to dissimilar anatomical information between DynaCT and T2-weighted MRI. Image visualization, initial alignment using a centered transformation initializer, and single-resolution image registration involving the Simple Insight Toolkit (SimpleITK) library were performed. Manual landmark-based alignment based on anatomical landmarks and evaluation metrics such as Target Registration Error (TRE) assessed alignment accuracy. Results: The registration method successfully aligned all images. Quantitative evaluation revealed an average of the mean TRE of 1.48 mm across all subjects, indicating satisfactory alignment quality. Multiplanar reformations (MPRs) based on electrode-oriented normal vectors visualized segmented contacts for accurate electrode placement. Conclusions: The developed method demonstrated successful registration between preoperative non-contrast T2-weighted MRI and postoperative DynaCT, despite dissimilar anatomical information. This approach facilitates accurate alignment crucial for DBS programming and postoperative verification, potentially reducing the programming time of the DBS. The study underscores the importance of image quality, manual initialization and semi-automated registration methods for successful multimodal image registration in dDBS procedures targeting the STN. Full article

Background/Objectives: Implant placement in cases of severe bone atrophy or compromised alveolar bone requires careful planning, especially in the anterior maxilla. The nasopalatine canal (NPC) and its cortical walls offer potential anchorage sites. This study evaluates the NPC’s anatomical characteristics using cone beam computed tomography (CBCT) to assess its suitability for implant anchorage. Methods: A retrospective analysis of 150 CBCT scans from three dental clinics in Poland was conducted. NPC measurements—including length, width, number of canals, and distances to adjacent anatomical structures—were taken in the sagittal, coronal, and axial planes. Statistical tests included Pearson correlation and Student’s t-test to explore relationships between NPC dimensions and gender. Results: The mean NPC length was 10.27 mm and mean width 3.55 mm. Significant gender differences were observed in the canal length, width, and distances to the labial and palatal plates (p < 0.05). Strong positive correlations were found between the canal width at the palate base and other parameters, such as the midpoint width (r = 0.58) and diameter (r = 0.44). The distance from the palatal opening to the labial plate showed the strongest correlation (r = 0.67), indicating enhanced cortical anchorage potential with increased canal dimensions. Discussion: NPC morphology varied (cylindrical, funnel-like, hourglass), aligning with prior studies. Larger diameters were linked to single-canal configurations. Implant placement strategies—such as direct canal insertion or lateralization—can be effective, especially with polished, single-piece implants that reduce soft tissue ingrowth and improve primary stability. Conclusions: Understanding NPC anatomy is crucial for implant planning in atrophic maxillae. With the proper technique, NPC use for cortical anchorage is a viable treatment option. Full article

Background/Objectives: Patient-specific osteosynthesis (PSO) plates, in combination with virtual surgical planning (VSP), have significantly improved the accuracy of orthognathic surgery. This study aimed to compare the surgical accuracy of two-plate versus four-plate fixation methods in Le Fort I osteotomies using PSO. Methods: A retrospective cohort study was conducted on 21 patients who underwent maxilla-first bimaxillary surgery at a single centre in 2024. Eight patients received two-plate fixation, while thirteen received four-plate fixation. All surgeries were planned using VSP. Postoperative cone beam computed tomography scans were used to assess the accuracy of maxillary positioning by comparing the planned versus achieved outcomes in terms of translation and rotation. Results: Both fixation methods yielded comparable results in maxillary positioning, with no significant differences observed between the two groups regarding translational or rotational deviations. The two-plate PSO approach demonstrated practical benefits, including reduced material usage and the potential for smaller surgical incisions, without compromising surgical accuracy. Conclusions: Two-plate PSO fixation is a viable alternative to the traditional four-plate method for Le Fort I osteotomies, offering similar accuracy with potential procedural advantages. While these findings support broader clinical adoption, further research is warranted to confirm the results in larger cohorts and to investigate biomechanical considerations. Full article