Search Results (341)

Kraft paper, as a typical archival packaging material, is prone to microbial erosion, flammability, and moisture-induced degradation during long-term preservation. In this work, multifunctional archival packaging paper with integrated flame retardancy, antifungal activity, and hydrophobicity was successfully fabricated via the modification of boron-based flame retardants (borax, BX, and disodium octaborate tetrahydrate, DOT) and silane hydrophobic agent (octadecyltrimethoxysilane, ODTMS). The structure and performance of the modified kraft paper were systematically characterized by the limiting oxygen index (LOI), the vertical burning test, cone calorimetry (CCT), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), contact angle measurement, and the antifungal test. The optimized modified sample exhibited superior comprehensive properties. The LOI value increased from 20.6% for the original kraft paper to 37.5%. TGA revealed that the char residue of the optimized modified sample at 750 °C reached up to 55.35%, much higher than that of the original kraft paper, accompanied by marked decreases in the heat release rate, total heat release, and smoke production. Meanwhile, ODTMS endowed the modified sample with hydrophobic properties, with a water contact angle of approximately 130°. Antifungal tests demonstrated that the modified kraft paper displayed obvious inhibitory effects against eight fungal species, including Penicillium citrinum and Aspergillus flavus. Overall, the modification strategy proposed in this study is simple, eco-friendly, and low-cost, achieving multifunctional protection of archival packaging materials. This work is expected to provide novel materials and technical support for the long-term safe preservation of paper cultural relics and archives. Full article

In the design of local application fire extinguishing systems, nozzles sometimes cannot be installed vertically due to space constraints and must be inclined. During inclined discharging, the discharge cone coverage pattern changes, and the high-concentration area shifts toward the front of the discharge direction, resulting in insufficient concentration at the rear of the fire source and compromising extinguishing effectiveness. Therefore, the nozzle aiming point must be offset toward the nozzle installation side. This discharge offset can compensate for the concentration deficiency at the rear of the discharge direction and ensure extinguishing effectiveness. This paper takes perfluorohexanone as the research object and, for the K100 swirl-core atomizing nozzle, conducts CFD numerical simulations and 70B pan fire full-scale extinguishing validation tests on discharge offsets at different inclination angles (90°, 75°, 60°, 45°). The research shows that the nozzle installation angle should not be less than 45°, and the offset increases as the angle decreases. The offsets of the K100 nozzle at 90°, 75°, 60°, and 45° are 0 mm, 66.34 mm, 101.34 mm, and 175.86 mm, corresponding to 0, 0.08R, 0.12R, and 0.22R (R is the protection radius), respectively. Compared with carbon dioxide standards, the offset required for perfluorohexanone is much smaller than that for carbon dioxide (approximately 1/2 to 1/3 of that of carbon dioxide at the same installation angle). A calculation formula for the offset based on the protection radius R is proposed, providing a design basis for precise nozzle positioning in local application systems under confined spaces or complex installation conditions. The generalizability of the proposed offset model is further validated through additional experiments using perfluoroheptanone, a high-boiling-point agent with similar physicochemical properties to perfluorohexanone. Full article

Alluvial fan source-to-sink (S2S) systems in Mars-analog environments are crucial for investigating planetary surface processes. However, traditional S2S analyses lack continuous regional coverage and topographic physical constraints. This study integrates GF-5A spaceborne hyperspectral imagery with DEM data to establish a regional-scale hyperspectral mineral spatial correspondence framework on the western margin of the Qaidam Basin. Using the Sequential Maximum Angle Convex Cone and Spectral Angle Mapper algorithms, we mapped two representative mixed mineral endmembers: clay–mica and Fe²⁺-bearing silicate mineral assemblages. A terrain-derived hydrological network was constructed to evaluate sub-catchment mapped mineral extents, potential source supply conditions, and potential near-source S2S relationships. The results indicate that the Fe²⁺-bearing silicate mineral assemblage exhibits a close spatial correspondence between source zones and near-source depositional zones, with broadly comparable mapped areas in the source region and proximal areas. Conversely, the clay–mica mineral assemblage displays strong spatial heterogeneity, showing a large-scale reduction in the central core channel. Synergistic validation combining DEM topographic dynamics with vertical spectral profiles from a single ground-based in-situ borehole provides preliminary support for the hypothesis that this surficial mineral differentiation may reflect hydrodynamic sorting and/or multi-stage continuous aggradation. While currently constrained by two-dimensional mapped surface area rather than mineral mass, an evaluation of three proximal pathways, and a preliminary single-core profile without extensive regional ground-truthing, this integrated framework provides a prospective terrestrial analog reference and methodological support for evaluating potential source-to-sink spatial correspondence and reconstructing paleohydrology on Mars. Full article

Background/Objectives: Detailed study of the anatomy of the maxillary sinuses is crucial for reducing the risk of complications in sinus augmentation and implant procedures, endodontic surgical treatment, and other operations in the posterior maxilla. This retrospective cone-beam computed tomography (CBCT) study aimed to investigate maxillary sinus volume, septal morphology and distribution, ostium height, and pathological findings, as well as their interrelationships, in a Saudi clinical cohort using combined three-dimensional volumetric and morphometric analyses. Methods: A retrospective analysis was performed on 360 CBCT scans obtained from patients after applying predefined inclusion and exclusion criteria. The volumes of the maxillary sinuses were measured by means of semi-automatic segmentation with ITK-SNAP software, while the structure of the septum, anatomical position, orientation, and internal architecture were assessed with BlueSky Bio software. The vertical distance from the natural opening to the bottom of the sinus and pathologies of the Schneiderian membrane were also studied. Results: The mean volume of the left maxillary sinus was found to be larger than the right (14,948.6 ± 5473.5 and 13,937.6 ± 4020.7 mm³, respectively). No sexual differences were noted with regard to sinus sizes. The prevalence of septa was 80.3% for the left side and 77.5% for the right side. The septa were mostly incomplete, with complete septa being less common. Various types of positioning and orientation were recorded for the septa, with a peak in the molar region. In the case of the left sinus, the height of the ostium was greater in men than women (p = 0.007); no differences were observed for the right side. Conclusions: The anatomy of the maxillary sinus shows great three-dimensional variation in terms of the shape of septa, the volume of the sinus, the height of the ostium, and any pathological changes related to that anatomy. The significant relationship between the presence of septa and the pathology of the mucosa highlights the need for adequate preoperative CBCT analysis of the anatomy. Full article

Background/Objectives: To evaluate the clinical effects of alveolar ridge preservation using a hyaluronic acid-based product combined with a resorbable collagen cone compared with spontaneous healing. Methods: In this prospective pilot comparative clinical study, extraction sockets were treated either with hyaluronic acid and a collagen cone (test group) or left to heal spontaneously (control group). Mesial and distal ridge height changes (ΔHm, ΔHd), ridge width reduction (ΔW), buccal mucosal thickness changes (ΔTmb), and occlusal mucosal thickness at 3 months (TmoT3) were assessed. Early wound healing was appreciated at 14 days follow-up, and postoperative complications after 7 and 14 days. Results: Complete 3-month follow-up data were available for 18 test and 14 control patients. Mesial bone loss was significantly lower in the test group than in controls [test ΔHm = 1.0 (1.0–1.0) vs. control ΔHm = 2.0 (1.0–2.0); p < 0.001]. Horizontal ridge width reduction was significantly lower in the test group [ΔW = 1.0 (1.0–1.0) vs. 2.0 (1.0–2.0); p = 0.021]. Buccal mucosal thickness was better maintained in the test group [ΔTmb = 0.0 (0.0–0.5) vs. 1.0 (0.5–1.0); p < 0.001], while TmoT3 was greater in the test group, in an exploratory analysis (p = 0.049). A statistically significant difference in early wound-healing scores favoring the test group was observed [4.0 (4.0–5.0) vs. 4.0 (3.0–4.0); p = 0.032]. No statistically detectable difference in postoperative complications was observed between groups. Conclusions: Alveolar ridge preservation was associated with reduced mesial vertical and horizontal dimensional changes and more favorable soft tissue outcomes compared with spontaneous healing. These preliminary findings should be considered hypothesis-generating. Full article

Objectives: We sought to evaluate CBCT-based dimensional outcomes, short-term dimensional changes, the feasibility of delayed implant placement, and complication profiles after defect-adapted guided bone regeneration of the atrophic edentulous maxilla using a PRGF-enriched autogenous bone/anorganic bovine bone mineral composite, including cases requiring simultaneous lateral-window sinus floor elevation. Materials and Methods: In this prospective, single-arm, non-randomized clinical case series, 11 patients with an atrophic edentulous maxilla requiring prosthetically guided reconstruction before implant placement were consecutively treated. Eligibility criteria included a residual ridge width < 6 mm and/or residual bone height < 10 mm, with ASA I–II status. Patients underwent defect-adapted GBR with a 60:40 mixture of autogenous bone and anorganic bovine bone mineral combined with plasma rich in growth factors (PRGF), stabilized within a defect-adapted barrier membrane system. Eight patients received combined vertical and horizontal augmentation, and three received horizontal augmentation, with simultaneous sinus floor elevation performed where anatomically indicated. Implants were placed in a delayed protocol at re-entry (6–9 months). Bone height and width were measured using standardized cone-beam computed tomography at baseline, immediately post-operatively, at 6–9 months, and at 12 months at three maxillary reference sites. Selected bone core biopsies obtained at re-entry were processed for descriptive histological evaluation. Results: Mean vertical bone dimension increased from 6.8 mm pre-surgically to 14.9 mm immediately postoperatively and measured 14.5 mm at 6–9 months and 13.9 mm at 12 months; mean horizontal bone dimension increased from 4.1 to 8.8 mm and measured 8.6 and 8.2 mm, respectively, at the corresponding follow-up time points. At 12 months, the retained mean dimensional gain was 7.1 mm vertically and 4.1 mm horizontally. Descriptive histological evaluation of selected bone core biopsies showed newly formed bone associated with residual bone-substitute particles and bone–biomaterial interface remodeling. In total, 75 implants were placed according to a delayed protocol. No intra-operative complications occurred. Three low-grade infections resolved without loss of the regenerative construct, whereas one high-grade infection caused complete graft loss at the affected site; it was excluded from the bone-gain analysis. Conclusions: Within its limitations, the PRGF-enriched autogenous bone/ABBM composite stabilized within a defect-adapted GBR compartment was associated with substantial vertical and horizontal augmentation of the severely atrophic edentulous maxilla, with limited mean linear dimensional reduction between the immediate postoperative and 12-month assessments. The approach enabled delayed implant placement in prosthetically guided positions. Controlled studies with longer follow-up are required to clarify the contribution of PRGF and validate the long-term functional performance of this multi-component regenerative biomaterial strategy. Full article

To address the challenges of limited storage space and mobile launch-and-landing operations for vehicle-mounted multirotor UAV swarms, this paper proposes a stackable Cone-Sleeve UAV swarm system. The UAV airframe incorporates a through-body central sleeve integrated with conical guidance structures, which cooperate with a vertical guide rod mounted at the center of the mobile platform to achieve geometric passive pose correction during landing. In addition, a UWB-based onboard local positioning and navigation system is developed, in which a tightly coupled UWB/IMU estimator is employed to achieve high-precision relative state estimation for the UAV swarm. A five-stage finite state machine (FSM) schedules the landing sequence. During terminal landing, a motion feedforward control strategy is introduced for dynamic motion compensation and to ensure seamless state transitions. Simulation and vehicle-mounted experimental results demonstrate that, strictly under low-speed (≤0.5 m/s), constant-velocity straight-line motion conditions, the proposed system enables autonomous vertical takeoff and landing as well as rapid stacked launch-and-landing operations for multiple UAVs. The cooperative guidance strategy integrating active control and the Geometric Passive Guidance (GPG) mechanism improves the precision and speed of swarm landing operations. The proposed system provides a feasible system-level solution for the storage, transportation, and autonomous rapid launch-and-landing of high-density UAV swarms. Full article

The mechanical compatibility between dental restorative materials and the natural tooth structure is a relevant factor for long-term clinical performance. Although zirconia (yttria-stabilized tetragonal zirconia polycrystal, Y-TZP) and lithium disilicate are widely used for full-coverage crowns, their biomechanical interaction with the underlying dentin and pulp under functional loading remains insufficiently characterized. This study reports a comparative finite element analysis (FEA) of a mandibular first molar under vertical (200 N, axial) and oblique (200 N, 30°) loading, evaluating three configurations: an intact healthy tooth, a zirconia Y-TZP full-coverage crown, and a lithium disilicate full-coverage crown. The three-dimensional geometry was obtained from a cone-beam computed tomography (CBCT) study of a caries-free mandibular first molar, previously described and verified by the present group, and was analyzed in ANSYS Workbench (Static Structural). Von Mises equivalent stress, maximum principal stress and total deformation were obtained for enamel or restoration, dentin, and pulp in each configuration. Zirconia produced the highest stress concentrations in the coronal restoration (88.4 MPa vertical; 174.5 MPa oblique), exceeding the healthy enamel baseline by 57.6% and 89.7%, respectively. Both restorative materials reduced dentin stress relative to the healthy tooth, consistent with the stress-shielding effect driven by elastic-modulus mismatch. Under oblique loading, the maximum principal stress in healthy enamel reached 61.7 MPa, approaching or exceeding the upper bound of the reported tensile strength range (~10–40 MPa) and identifying oblique loading as the more demanding of the two conditions analyzed. Within the limitations of the present finite element model, lithium disilicate demonstrated a more favorable stress distribution, with dentin stress values closer to the intact-tooth baseline. The model does not include a luting cement layer, a periodontal ligament, the dentin–enamel junction, anisotropic tissue behavior or cyclic loading, and no experimental validation was performed; the results are therefore presented as a controlled numerical comparison between three configurations under the specific conditions simulated, and not as direct clinical selection criteria. Full article

Geometric misalignment degrades industrial cone-beam computed tomography (CBCT), particularly when a dedicated calibration phantom cannot be deployed during object acquisition. This study presents a three-stage, scan-specific geometric refinement framework that searches a bounded five-coordinate correction space around a nominal geometry. Coarse candidates are screened using the normalized residual between a geometry-corrected center-of-mass trajectory and its best-fitting low-order periodic model. Translation- and rotation-dominant coordinates are then refined within system-specific physical bounds, and an energy-normalized nuclear-norm score of corrected row-wise sinograms is used for local correlation refinement. The periodic and low-rank terms are treated as object-dependent surrogate objectives rather than as standalone guarantees of physical parameter identifiability. An exact-ASTRA implementation check using a Shepp–Logan volume verified the detector-plane reindexing convention: applying the injected correction reduced valid-mask projection discrepancy to 35.2%, 13.7%, and 8.66% of the uncorrected values for small, medium, and large perturbations, respectively, with round-trip resampling NRMSE of 0.022–0.023 and a mean valid fraction of 98.4%. Three industrial datasets acquired with horizontal gantry CT, temperature-stage in situ CT, and vertical micro-CT provided comparative reconstruction evidence. In addition, a controlled reduced-resolution industrial object reprojection benchmark was used for direct comparison with MI-PSO, PR, and a stability-regularized implementation of the public epipolar-consistency formulation (Open-ECC-R). Over 20 fixed-ROI axial slices, Open-ECC-R increased the mean SSIM from 0.6852 ± 0.0454 for the uncalibrated reconstruction to 0.8450 ± 0.0155 and reduced the NRMSE from 0.5180 ± 0.0526 to 0.1671 ± 0.0125. The proposed method achieved the highest mean SSIM of 0.9933 ± 0.0002 and the lowest NRMSE of 0.0321 ± 0.0009. For the Bluetooth earphone dataset, local sagittal and axial MTF₅₀ estimates increased from 0.84 to 0.94 lp/mm and from 0.45 to 1.05 lp/mm, respectively. These results support scan-specific image-quality refinement around a nominal geometry while avoiding unsupported claims of absolute parameter recovery. Full article

The currently common procedures in orthognathic surgery are widely used. Different forms of skeletal malocclusion can be treated with great outcomes in terms of bite, bone harmony, function, improved mastication, esthetics, and even decreased problems with breathing. Each type and intensity of malocclusion may affect decision-making in terms of distraction, selection of osteotomy design, or even guide clinical and surgical decisions to use a less popular osteotomy protocol. CBCT (cone-beam computed tomography) is currently a milestone in the establishment of the condition of jaw bones, bone structure, temporomandibular joints, and central relation (CR), as well as the scope of maxilla–mandibular and tooth relations. When establishing all of the following in a clinical and radiological (CBCT-based) evaluation, it becomes possible to measure the occlusal plane, height, length, and three-dimensional position of each dental segment, as well as other dentoalveolar features. In the present case, CBCT helped distinguish a localized vertical anterior mandibular dentoalveolar discrepancy from generalized mandibular malposition and supported the planning of a mandibular anterior segmental subapical osteotomy (MASSO) by mapping the osteotomy corridor in relation to the dental roots, cortical bone, periapical bone height, and neurovascular structures. Significant therapeutic complexity emerges when severe skeletal Class III malocclusion (mandibular prognathism) is compounded by transverse maxillary discrepancies and a markedly elevated mandibular anterior segment. This constellation of deformities leads to profound disturbances in the anterior facial height, a disrupted maxillomandibular interincisal relationship, and the loss of a level occlusal plane. The presented case highlights how the patient’s clinical evaluation should be carefully compared with radiological data, status of both cortices in the mandible, the height of the mandibular anterior segment, presence of gum recessions and poor bone status that may affect healing, osteotomies, and occurrence of some unwanted events. Therefore, CBCT was useful not only for diagnosis and planning, but also for understanding the biological limits of movement and the risk of postoperative periodontal complications in this uncommon reversed Köle-type MASSO. Full article

Background: Achieving a three-dimensional seal of the root canal system is considered essential for long-term endodontic success. Because no clinically acceptable threshold for void formation has been established, comparisons with clinically validated reference materials are needed to interpret the sealing quality of newer calcium silicate-based sealers (CSBSs). AH Plus is a well-established epoxy resin-based sealer (ERBS) with documented long-term clinical performance. This systematic review and meta-analysis compared the quality of root canal fillings produced with CSBSs and AH Plus using different obturation techniques in permanent mature extracted and artificial teeth. Methods: MEDLINE (PubMed), EMBASE, Cochrane Library, and Web of Science were systematically searched for randomized in vitro studies up to 1 July 2025. The primary outcomes were the percentages of void volume or area. Mean values and mean differences (MDs) with corresponding 95% confidence intervals (CIs) were calculated for the total filling volume and, where available, for the apical, middle, and coronal thirds of the root canal. Risk of bias and certainty of evidence were assessed. Results: Twenty-one studies met the eligibility criteria, and 18 articles were included in the quantitative analysis. No statistically significant differences were observed in total void volume between CSBSs placed with the single-cone technique and AH Plus used with either the single-cone or warm vertical compaction technique in extracted teeth. Similarly, no significant differences were observed between the investigated groups in the apical, middle, or coronal thirds of the root canal. Evidence for other obturation techniques and artificial teeth was limited. Conclusions: Within the limitations of the available in vitro evidence, no statistically significant differences in void formation were detected between the investigated sealer–technique combinations. Further standardized in vitro studies and well-designed clinical investigations are warranted. Full article

X-ray computed laminography (CL) is a promising nondestructive testing technique for plate-type objects and is of great importance in 3D imaging. Nevertheless, its scanning geometry results in a lack of projection data along in-plane directions, causing severe inter-slice aliasing and cone-beam artifacts, especially under sparse-view sampling. To address this challenge, a prior image-guided adaptive-weighted relative total variation (PiAwRTV) algorithm is proposed for sparse-view CL. Based on relative total variation (RTV), PiAwRTV leverages structural information from a high-quality prior image to guide image reconstruction and introduces weights that vary with local image gradients. The reconstruction model incorporates 2D PiAwRTV in the horizontal direction to perform edge-preserving smoothing and 1D PiAwRTV in the vertical direction to suppress inter-slice blurring. An alternating minimization strategy is employed to decompose this optimization problem into three subproblems for iterative solution. Experimental results demonstrate that the proposed algorithm reconstructs key structural features while reducing cone-beam artifacts, significantly improving the imaging quality of sparse-view CL. Full article

Background: Management of post-extraction sockets with buccal dehiscence in the esthetic zone remains clinically challenging, particularly when immediate implant placement is indicated. Conventional approaches often rely on guided bone regeneration (GBR) with biomaterials, which may increase surgical complexity and morbidity. This case report evaluates the clinical and radiographic outcomes of a fully autologous approach combining leukocyte- and platelet-rich fibrin (L-PRF) and connective tissue graft (CTG) in conjunction with immediate implant placement. Methods: A 50-year-old healthy patient presenting with a fractured maxillary lateral incisor and buccal bone dehiscence underwent atraumatic extraction, immediate implant placement, and simultaneous site management using L-PRF membranes and CTG. Clinical and radiographic evaluations were performed at baseline (T0) and after 12 months (T1). Cone-beam computed tomography (CBCT) was used to assess horizontal bone thickness (HBT) at multiple apico-coronal levels and vertical evaluation parameters, including nasal floor–crest distance (NF–AC). Clinical outcomes included probing pocket depth (PPD), keratinized tissue width (KT), gingival thickness (GT) and patient-reported outcome measures (PROMs). Results: Radiographic analysis demonstrated increased HBT at all levels (+1.4 mm at 9 mm, +3.1 mm at 12 mm, +3.2 mm at 15 mm, and +2.6 mm at 18 mm). NF-AC showed a marked increase (+2.7 mm) and substantial reduction in the buccal dehiscence defect. Clinically, KT increased by +2.0 mm and GT by +1.8 mm. Healing was uneventful, with minimal postoperative discomfort and high patient satisfaction. Conclusions: Within the limitations of a single case report, the combined use of L-PRF and CTG with immediate implant placement was associated with favorable clinical and radiographic outcomes. These preliminary findings suggest that a fully autologous, biologically driven approach may represent a potential alveolar ridge preservation strategy and a biomaterial-sparing alternative to conventional GBR in carefully selected cases. Further controlled studies are required to confirm these observations and define the indications and limitations of this approach. Full article

Bioceramic sealers have gained widespread acceptance in contemporary endodontics due to their favorable biological properties, dimensional stability, and bioactivity. However, their strong adhesion to dentinal walls and penetration into dentinal tubules may complicate removal during endodontic retreatment procedures. Additionally, the obturation technique may influence both the retreatability of root canal filling materials and the bond strength of sealers and resins to radicular dentin. Methods: One hundred extracted human single-rooted teeth were instrumented using the WaveOne Gold system and obturated with a bioceramic sealer using two techniques: single-cone (Group A, n = 50) and warm vertical compaction (Group B, n = 50). After sealer setting, retreatment procedures were performed using ProTaper Universal Retreatment files combined with passive ultrasonic irrigation. Scanning electron microscopy was used to evaluate smear layer removal and dentinal tubule obstruction. Eighty specimens were subsequently re-obturated with a bioceramic sealer and divided into four subgroups according to the obturation technique used before and after retreatment. A push-out bond strength test was performed on coronal, middle, and apical root sections. Statistical analysis was conducted using SPSS software with a significance level set at p ≤ 0.05. Results: No statistically significant differences were observed between the groups regarding the working time required for root filling removal (p > 0.05). However, significant differences were found in push-out bond strength values among the experimental groups (p < 0.05). Specimens obturated using warm vertical compaction showed significantly higher bond strength compared with the single-cone technique. Scanning electron microscopy observations revealed less residual bioceramic sealer on dentinal walls in the warm vertical compaction group. Conclusions: Within the limitations of this in vitro study, the warm vertical compaction technique demonstrated superior bonding performance and resulted in less residual bioceramic sealer after retreatment compared with the single-cone technique. Full article

Objectives: The aim of the study was to compare CBCT (Cone Beam Computed Tomography)-derived radiographic hard tissue gain after hydraulic transcrestal sinus floor elevation performed with versus without cross-linked hyaluronic acid (HA) and to assess associated clinical, radiographic, and patient-reported outcomes. Materials and Methods: This single-center, prospective clinical study enrolled 58 patients with 2–6 mm residual bone height in the posterior maxilla, assigned in a non-randomized parallel-group design to HA (n = 29) or No Graft (n = 29). The primary endpoint was CBCT-based 3D CBCT-derived radiographic hard-tissue volume gain at 12 months; secondary endpoints included vertical bone gain, marginal bone loss (MBL) at 12 and 24 months, implant stability quotient (ISQ), implant survival/success, complications, and patient-reported outcomes (VAS pain, OHIP-14). Analyses used ANCOVA and appropriate comparative statistics. Results: At 12 months, mean CBCT-derived radiographic hard-tissue volume gain was higher with HA (1210 +/− 610 mm³) than with No Graft (858 +/− 605 mm³; adjusted difference +352 mm³, 95% CI: 140–564; p = 0.002). ISQ at 12 months was greater with HA (p = 0.028), while MBL at 12/24 months did not differ significantly. Twenty-four-month implant survival was 98.1% (HA) vs. 94.3% (No Graft; p = 0.041). Complication rates were low and comparable; VAS pain at 72 h was modestly lower with HA. Conclusions: In this non-randomized prospective clinical study, cross-linked hyaluronic acid was associated with greater CBCT-derived radiographic hard-tissue volume gain and vertical radiographic gain after hydraulic transcrestal sinus floor elevation compared with clot stabilization alone. Clinical outcomes were favorable in both groups during the 24-month observation period. These findings support the interpretation of cross-linked hyaluronic acid as a potential space-maintaining adjunct in posterior maxillary sites with limited residual bone height; however, because no histological or histomorphometric assessment was performed, they should not be interpreted as proof of vital mature bone regeneration or superior bone quality. Full article