Search Results (302)

The success of dental implantation depends on both mechanical stability and the host’s immune response to the implanted biomaterials. Osteoimmunology emphasizes that early immune responses at the implant-tissue interface are critical for bone healing and long-term osseointegration. The immune response primarily consists of immune cells, particularly macrophages, neutrophils, and lymphocytes, which interact with osteogenic cells through cytokine networks and signalling pathways, such as RANK/RANKL/OPG. Additionally, it modulates both bone formation and resorption. This review focuses on summarizing the mechanisms that shape the immune response around implants by dental implant materials. It describes mechanisms related to bulk composition, surface topography, and mechanical properties, and highlights macrophage polarization and the transition from inflammation to regeneration. The review discusses current immunomodulatory strategies, including bioactive surfaces, ion doping, nanopatterning, drug-releasing surfaces, and responsive materials, as well as advances enabled by additive manufacturing. The review also discusses experimental models used to study osteoimmunological interactions and the clinical significance of immune dysregulation in peri-implant diseases. The design of biomaterials based on osteoimmunology represents a shift toward immune-compatible implants that aim to improve regenerative outcomes and long-term implant success. Full article

Background: Severe jaw atrophy (Cawood and Howell Class V–VI) often renders conventional endosseous implantation unfeasible due to the lack of medullary bone and vascularization. This study presents a digital workflow for customized subperiosteal implants designed to eliminate bone segmentation errors and ensure optimal passive fit. Methods: Two clinical cases of severe atrophy—a full-arch maxillary rehabilitation and a unilateral partial rehabilitation—were treated using a prosthetic-driven CAD/CAM workflow. Key innovations included densitometric mapping using Hounsfield Units (HU) to identify high-mineralization zones (+1200 to +1800 HU) for strategic screw fixation. Intraoperatively, cobalt–chrome osteoplasty guides and PMMA check-templates were utilized to validate bone segmentation accuracy in vivo and regularize the cortical base. Results: The protocol achieved high precision with a monitored alignment deviation of 0.2 mm. At the 2-year follow-up, clinical and radiographic evaluations (CBCT) confirmed the total absence of gaps at the bone–implant interface. No signs of peri-implantitis, osteolysis, or progressive bone loss were observed, and soft tissues remained stable and healthy. Discussion: Success was driven by the rigorous management of the bone–implant interface and the use of preparatory surgical devices to bridge the gap between digital planning and surgical reality. The mechanical stability achieved through divergent fixation vectors prevented stress shielding by converting shear forces into compression, stimulating basal bone density according to Wolff’s Law. Conclusions: The standardized digital workflow and the use of preparatory surgical devices in this preliminary study showed that complex rehabilitations can be performed with favorable short-term outcomes. While this approach reduces surgical time and biological stress, further prospective studies are required to confirm its clinical predictability and define next-generation subperiosteal implants as a valid alternative for the management of severely atrophic cases. Full article

This is a retrospective, single-center cohort study comparing the long-term radiographic osseointegration and aseptic loosening between a 3D-printed EPORE^® collar and a prior generation HA-coated collar in endoprosthetic reconstructions. Achieving stable bone integration in endoprosthetic reconstructions remains challenging, with hydroxyapatite (HA)-coated collars being the only option available in the past. Earlier studies from our center have shown reliable and accelerated osseointegration at the bone–collar interface using a novel highly porous 3D-printed EPORE^® collar system compared to a previously used HA-coated collar. Methods: Twenty-eight patients who underwent an implantation of endoprostheses utilizing the novel 3D-printed EPORE^® collar system were case-matched to 24 patients who had previously undergone surgeries using a HA-coated collar. The mean age at surgery was 65.2 years (range: 17–95 years). Patients in the HA-coated collar group had a mean age of 63.8 years (range: 17–86 years), while those in the 3D-printed collar group had a mean age of 66.7 years (range: 32–95 years), with no statistically significant difference between groups (p = 0.876). A minimum radiological and clinical follow-up of 2 years was available in all included cases. Osseointegration was evaluated using postoperative plain radiographs in two planes based on a previously validated semi-quantitative score. Results: When aseptic loosening was used as the primary endpoint, no failures occurred in the 3D-printed EPORE^® group during the study period. The overall rate of stem loosening (including both aseptic and septic causes) was 7% (2/28) in the 3D-printed group and 16% (4/24) in the HA-coated group. All cases of loosening in the 3D-printed cohort were related to septic failure. This translates into a 2-year aseptic-loosening-free survival of 100% in the 3D-printed group. When the radiographic osseointegration was analyzed as the endpoint, the rate of successful osseointegration was significantly higher in the 3D-printed group (92.9%, 26/28; 95% CI 76.5–99.1%) compared with the HA-coated group (70.8%, 17/24; 95% CI 48.9–87.4%; p = 0.04). The distribution of ongrowth scores also differed significantly between groups. The highest ongrowth score (grade 4) was achieved in 82.14% of 3D-printed implants (23/28; 95% CI 63.1–93.9%), compared with 37.5% of HA-coated implants (9/24; p = 0.0002). The time to achieve grade 4 ongrowth was significantly shorter in the 3D-printed cohort, with a median of 470 days (IQR 360–610), compared with 1482 days (IQR 1020–1860) in the HA-coated group (p < 0.0001). In addition, patients in the 3D-printed implant group had a significantly higher mean body mass index compared with the HA-coated group (32.51 vs. 28.36, p = 0.01). Conclusions: These results show that the novel highly porous 3D-printed EPORE^® collars reduce aseptic loosening and accelerate extracortical bridging in endoprosthetic replacements. This benefit persisted even in higher BMI or revision contexts when compared to the previously used HA-coated collars. Full article

The synthesis of reactive sucrose derivatives is of significant interest for the development of novel biocompatible polymers. In this study, an octa-substituted sucrose derivative containing isocyanate groups was synthesized via a urethane-forming reaction carried out in an aprotic solvent at the phase interface. This approach exhibits high selectivity and provides a target product yield of up to 60%. Subsequently, using the same reaction mechanism, the isocyanate derivative was converted into an octa-functional methacrylate derivative capable of forming three-dimensional cross-linked networks. The structures of both the intermediate and final products were confirmed by IR, ¹H NMR, and mass spectrometry. The sucrose-based prepolymer was further evaluated in the formation of cross-linked structures for potential application as bone-substituting implants. Using various photocuring techniques, including two-photon 3D printing, both plates and microstructured scaffolds were fabricated. These structures exhibited high thermal stability, elastic properties comparable to those of bone tissue, and no toxic effects on cells. Full article

Background/Objectives: This narrative review aimed to critically assess the role of multi-unit abutments in implant dentistry, focusing on mechanical reliability and biological stability at the implant–abutment interface. Methods: A literature search was performed in PubMed/MEDLINE, Scopus, Web of Science and Google Scholar to identify clinical studies and experimental research from the past 20 years addressing implant–abutment connections, mechanical complications and biological integration of multi-unit abutments. Results: Dental implants demonstrate survival rates above 95%, yet complications, up to 35%, are primarily linked to the implant–abutment interface. Mechanical issues, especially screw loosening, may be mitigated with conical connections and adherence to evidence-based protocols. Biologically, multi-unit abutments with sufficient transmucosal height contribute to stable supracrestal tissue and preservation of marginal bone. Advances such as nanostructured surfaces and the concept of mucointegration represent a shift toward biologically active interfaces, enhancing peri-implant soft tissue health. Conclusions: Multi-unit abutments have evolved from simple angulation-correction tools to essential components across a wide range of clinical applications. Their success relies on strategic, protocol-driven use that integrates mechanical strength with biological harmony, enabling potentially favorable outcomes in modern implant dentistry, particularly in well-selected clinical scenarios. Full article

Background/Objectives: Horizontal alveolar ridge resorption following tooth loss often compromises implant placement and requires augmentation procedures to restore adequate bone volume. This pilot case series descriptively evaluated the clinical, radiographic, and histological outcomes of lateral ridge augmentation (LRA) using a collagenated porcine-derived xenograft combined with autogenous bone. Methods: Three consecutive partially edentulous patients presenting with severe horizontal ridge deficiency (residual bone width ≤ 4 mm) underwent LRA using a mixture of porcine-derived xenograft and autogenous bone covered with a resorbable collagen membrane. After a healing period of 3–5 months, core biopsies were harvested at implant placement and subjected to histological and histomorphometric analysis, including TRAP staining. Results: All sites healed uneventfully without intraoperative or postoperative complications. Radiographic evaluation demonstrated substantial horizontal bone gain, allowing placement of standard-diameter implants. Histological analysis revealed newly formed trabecular bone, residual graft material, and well-vascularized connective tissue, indicating active bone regeneration and biomaterial integration. TRAP-positive multinucleated giant cells (MNGCs) were observed at the biomaterial interface, suggesting ongoing remodeling. Long-term follow-up (mean 54.2 months) showed stable implant function without biological or mechanical complications. Conclusions: Within the limitations of this pilot case series, LRA using a collagenated porcine-derived xenograft combined with autogenous bone demonstrated preliminary favorable clinical, radiographic, and histological outcomes. Full article

Implantation of a femoral stem in total hip arthroplasty alters physiological load transfer within the proximal femur. Short-stem designs aim to preserve bone stock and maintain proximal load sharing, yet the influence of femoral neck resection height and its interaction with femoral morphology on primary stability remain insufficiently understood. This in vitro biomechanical study investigated these effects using 33 human femora classified as Dorr B or C. In a paired design, a cemented calcar-guided short stem was implanted with either a low (standard) or +5 mm higher femoral neck resection. Specimens underwent cyclic fatigue loading to assess reversible and irreversible micromotion and interface strain, followed by ultimate compression to quantify global fixation strength. Primary stability was assessed by reversible and irreversible translation of the prosthetic head center of rotation and by cortical interface strain measurements using digital image correlation. Overall fixation strength and irreversible deformation remained comparable across resection heights and Dorr types. In contrast, resection height and femoral morphology influenced reversible micromotion and interface strain, with higher resection reducing reversible micromotion, particularly in Dorr C femora and shifting lateral interface strain toward compression. These findings suggest that surgical technique and femoral morphology mainly affect local, reversible bone–cement–implant mechanics rather than global fixation strength. Full article

Background/Objectives: Immediate provisionalization in the esthetic zone is a well-documented but technique-sensitive procedure, and the choice of provisional connection geometry, with or without an antirotational index, remains debated. The aim of this retrospective single-arm cohort clinical study was to evaluate the clinical performance of a digitally planned, guide-delivered provisionalization protocol using prefabricated provisional crowns connected to 5-degree Morse taper implants without an antirotational index, with emphasis on emergence profile shaping and peri-implant tissue stability at one year; Methods: Twenty consecutive single-implant cases treated according to the standardized protocol from January 2024 onward and completing at least one year of follow-up after definitive crown delivery by the February 2026 data-lock date were included (19 female, 1 male; mean age 38.1 ± 12.7 years; 18 anterior and 2 premolar sites). All implants were placed with primary insertion torque ≥ 30 N·cm (mean 34.75 ± 2.55 N·cm) and immediately restored with a digitally designed, non-antirotational provisional crown. Primary outcome was provisional retention without major intervention; secondary outcomes included biologic complications, papilla score, marginal bone change at T0–T3 and T3–T4, and buccal contour change (T0 vs. T2 intraoral scan superimposition). Wilson 95% confidence intervals, Fisher’s exact test, and Mann–Whitney U test were used (α = 0.05); Results: Provisional retention without major intervention was 75.0% (15/20; 95% CI 53.1–88.8). Biologic complications were uncommon (bleeding on probing, suppuration, midfacial recession, and chairside adjustment, each 5.0%). Mean total marginal bone loss at one year was 0.37 ± 0.20 mm; mean buccal contour gain was 1.41 ± 0.48 mm. A complete papilla was preserved in 70.0% of cases. Conclusions: Digitally planned, guide-delivered provisionalization on a non-antirotational 5-degree Morse taper interface appears clinically feasible for emergence profile shaping in the esthetic zone, with favorable peri-implant tissue outcomes at one year. Full article

Interbody fusion cages are widely used to restore spinal stability, yet conventional designs often exhibit mechanical mismatch and limited biological integration. Functionally graded spinal cages incorporate spatial variations in composition and structure to better align mechanical properties with the surrounding bone environment. Although these designs have been extensively studied from an engineering perspective, their biological implications remain less clearly defined. This review examines how graded material composition, surface characteristics, porosity, and lattice architecture are associated with cellular and molecular responses relevant to bone regeneration. Reported biological responses include protein adsorption, immune modulation, angiogenesis, and osteogenic differentiation. Evidence from orthopaedic implants and tissue engineering systems suggests that such design features may influence mechanobiological pathways; however, direct experimental validation in spinal applications remains limited. Previous reviews primarily focus on material properties or mechanical performance of functionally graded spinal cages. This review presents a structured design-to-biology perspective linking graded implant features with biological responses relevant to spinal fusion. By integrating findings across biomaterials, mechanobiology, and implant design, this review presents a structured design-to-biology perspective and highlights current evidence, translational limitations, and key knowledge gaps in the field. Functionally graded spinal cages represent a promising but still evolving strategy, and further spine-specific mechanobiological and clinical studies are required to establish their impact on fusion outcomes. Full article

Treating fractures involving complex bone defects remains a major challenge in regenerative medicine. Additive manufacturing enables the fabrication of patient-specific implants, while surface anodization may enhance osseointegration by improving cell adhesion at the bone–implant interface. This study evaluated the feasibility of porous Ti-6Al-4V implants produced by additive manufacturing and surface-modified by anodization for repairing critical-sized femoral defects. Eighty rats were assigned to four groups: control (no graft), non-anodized Ti-6Al-4V implants, nanoporous implants, and nanotubular implants. After six weeks, bone regeneration and mechanical performance were assessed. Newly formed bone volume was significantly higher in the implanted groups compared to control (24.62 ± 3.11%), reaching 47.25 ± 3.92% (non-anodized), 58.20 ± 5.39% (nanoporous), and 40.72 ± 2.22% (nanotubular). Bone strength was also greater in implanted groups (150.27 ± 2.94 N, 151.98 ± 10.37 N, and 156.59 ± 4.95 N, respectively) compared to control (128.16 ± 2.17 N), with no significant differences among treated groups. No signs of implant rejection or inflammation were observed, indicating good biocompatibility. Anodized surfaces demonstrated enhanced osteogenic performance, particularly in the nanoporous group. These findings indicate that anodized porous Ti-6Al-4V implants produced by additive manufacturing combine biological compatibility with mechanical stability, supporting their potential application in bone reconstruction therapies. Full article

Background/Objectives: Electrolytes used in in vitro corrosion testing critically determine the behavior inferred for metallic dental implants, yet formulations and their justifications are inconsistently reported across the literature. This review compiles and compares electrolytes employed to simulate the oral cavity and the bone–implant interface, linking their chemical composition to the corrosion mechanisms they target. Methods: This structured narrative review synthesized peer-reviewed literature on simulated electrolytes used for in vitro corrosion testing of metallic dental implants and implant-related alloys. Literature was identified using database searches and targeted reference screening, with emphasis on artificial saliva formulations, physiological simulated fluids, challenge chemistries, protein-containing media, hydrodynamic conditions, and microbiological models. Relevant formulations were standardized to grams per liter and grouped according to application domain and targeted corrosion mechanisms. Results: The analysis maps electrolyte selection to corresponding corrosion modes, including uniform dissolution, pitting, crevice, galvanic, and microbiologically influenced corrosion. Consolidated composition tables highlight how pH, halide concentration, calcium–phosphate balance, proteins, gas control, and flow conditions modify passive-film stability and metal-ion release. Dental-specific gaps are identified, notably the lack of a standardized fluoride–pH matrix and limited guidance for microbiome-integrated assays. Conclusions: Aligning electrolyte formulations with the research question enhances reproducibility and mechanistic interpretation. However, current in vitro corrosion data should be interpreted cautiously because quantitative links between simulated-fluid testing and clinical outcomes such as peri-implantitis, peri-implant bone loss, and implant failure remain insufficiently established. The adoption of shared reporting standards, dynamic programmable chemistries, and interoperable datasets may improve the translational value of future corrosion studies. Full article

Implant-associated acute inflammation remains a major challenge in orthopedic, dental, and maxillofacial applications, often impairing osseointegration and leading to early implant failure. In this study, multifunctional cellulose acetate/hydroxyapatite–dexamethasone (CA/HA–DEXA) composite membranes were developed to locally modulate inflammation while supporting early bone–implant interactions. Cellulose acetate provides a flexible matrix, hydroxyapatite enhances bioactivity and osteoconductivity, and dexamethasone acts as an anti-inflammatory agent. The membranes exhibited composition-dependent swelling and drug release behavior. The swelling degree decreased from ~11% for pristine CA to ~5% for the highest HA–DEXA loading, indicating a denser structure with restricted water uptake. Dexamethasone release showed a biphasic profile, with cumulative release reaching ~68%, ~88%, and ~93% for 0.5%, 1%, and 2% HA–DEXA loadings after 72 h, respectively. In vitro evaluation indicated improved biomineralization for CA/HA–DEXA membranes compared to neat CA, attributed to the role of hydroxyapatite as a nucleation promoter. These findings suggest that CA/HA–DEXA composite membranes represent a promising strategy for controlling early inflammatory responses while supporting bone regeneration at the implant interface. Full article

The design of implant surfaces that support bone integration while limiting bacterial colonization remains a central challenge in biomaterials science and engineering. In this work, zinc-doped biomimetic calcium phosphate (CaP-Zn) coatings were fabricated on Ti6Al4V through surface activation followed by deposition in supersaturated simulated body fluid (SBF). Acid and alkali–calcium treatments produced a porous, calcium-rich interface that enabled the uniform formation of apatite-like CaP layers. Zinc incorporation was achieved without suppressing the formation of CaP phases and led to systematic changes in coating microstructure and surface chemistry. Spectroscopic and structural analyses indicated Zn incorporation within the CaP matrix, consistent with partial Ca²⁺ substitution and its association with poorly crystalline domains. These features promoted controlled ionic release and localized dissolution–reprecipitation behavior. Antibacterial testing against Streptococcus mutans revealed a clear Zn-dependent reduction in bacterial viability, while cytocompatibility remained within acceptable limits at moderate Zn levels. Finally, the coatings combine intrinsic bioactivity with ion-mediated antibacterial functionality, offering a multifunctional surface strategy for advanced titanium-based implants. Full article

Microleakage at the implant–abutment interface represents a potential pathway for bacterial penetration and may contribute to peri-implant inflammation, marginal bone loss, and mechanical complications such as screw loosening. The increasing clinical use of compatible prosthetic abutments as cost-effective alternatives to original components has raised concerns regarding their fit, sealing capacity, and mechanical stability at this interface. The aim of this in vitro study was to evaluate differences in sealing capacity and torque loss between original and non-original abutments in a mixed internal connection implant system and to investigate the applicability of a novel quantitative approach for assessing microleakage based on a hydraulic conductance perfusion system. Nine abutments, including four multi-unit and five screw-retained cementable abutments, were connected to Straumann Bone Level implants at two tightening torques (5 N·cm and 35 N·cm). Microleakage was quantified by measuring fluid transport across the implant–abutment interface using the perfusion system, and removal torque values were recorded after testing. Non-original abutments exhibited significantly greater microleakage than original abutments at both torque levels. Microleakage increased significantly when the installation torque was reduced to 5 N·cm. At the manufacturer-recommended torque, screw-retained cementable abutments demonstrated higher microleakage than multi-unit abutments. Non-original abutments also showed significantly greater torque loss. These findings suggest that original abutments provide improved sealing capacity and mechanical stability at the implant–abutment interface, while the hydraulic conductance perfusion system represents a promising quantitative tool for investigating microleakage. Full article

Biodegradable metals represent a paradigm shift in orthopedic fixation by providing temporary mechanical support synchronized with bone healing while eliminating long-term complications associated with permanent implants. Conventional bioinert alloys, including stainless steels, Ti-based alloys, and Co-Cr alloys, exhibit high elastic moduli that induce stress shielding and often require secondary removal surgeries. In response, resorbable metallic systems based on Mg, Zn, and Fe have emerged as promising alternatives. Among these, Fe-Mn-C alloys stand out for load-bearing applications due to their exceptional strength-ductility balance governed by twinning-induced plasticity mechanisms, tunable degradation behavior, and intrinsic magnetic resonance imaging compatibility through austenitic phase stabilization. Focusing on Fe-Mn-C alloys, this review critically examines the metallurgical design principles underlying stacking fault energy optimization, phase stability, and Mn-controlled electrochemical behavior. Processing innovations, such as additive manufacturing, are discussed as tools to architecture porosity, refine microstructure, and accelerate degradation by graded designs while preserving mechanical structural support during healing. Hybrid metallic-bioactive systems, surface functionalization strategies, and functionally graded porous architectures were evaluated as advanced approaches to enhance osteointegration and modulate degradability. Despite these advances, significant barriers remain for clinical translation. Persistent discrepancies between in vitro and in vivo degradation rates, often attributed to biological encapsulation and degradation product accumulation, complicate lifetime prediction. Localized corrosion at microstructural heterogeneities such as twin boundaries and phase interfaces can undermine structural reliability under load-bearing conditions. Moreover, predictive multi-physics modeling frameworks capable of coupling electrochemical kinetics, mechanical loading, microstructural evolution, and bone remodeling remain underdeveloped, limiting reliable safety-margin estimation. Regulatory progress is further hindered by the absence of standardized testing protocols specifically tailored to Fe-based biodegradable alloys, including harmonized degradation rate windows, validated corrosion-mechanics coupling methodologies, and clinically defined Mn ion release thresholds. This review aims to discuss whether Fe-based alloys, especially Fe-Mn-C alloys, can transition from promising laboratory materials to clinically viable next-generation orthopedic implants capable of delivering patient-specific, mechanically compatible, and biologically synchronized temporary fixation. Full article