Prosthesis, Volume 7, Issue 6 (December 2025) – 39 articles

Background: Nylon-based removable partial dentures, such as Valplast^® (Valplast International Corp, Westbury NY, USA), have been proposed as a valuable alternative to acrylic resin prostheses, particularly following oral surgical extractions and in patients with suspected methacrylate hypersensitivity. This review aimed to evaluate the clinical indications guiding the use of nylon-based prostheses after oral surgical extractions and to investigate their prevalence in patients with documented acrylic allergies. Methods: Following PRISMA 2020 guidelines, a comprehensive search was conducted in six databases (PubMed, Scopus, Embase, Google Scholar, LILACS, and Cochrane Library) for studies published between 2015 and 2025. Eligible studies were critically appraised using the Joanna Briggs Institute (IBI) tools. Results: Nine studies met the inclusion criteria, all of which were low-level evidence (six case reports and three case series), comprising a total of 11 patients (mean age 43 years). Nylon-based prostheses were used in both maxillary and mandibular arches, with rehabilitation motivated by esthetic and functional reasons. Outcomes were generally favorable, with patients reporting satisfaction in terms of comfort, function, and esthetics. Conclusions: Current evidence supporting the use of nylon-based removable partial dentures remains extremely limited and is based exclusively on case reports and small case series. While this type of prostheses represents a viable post-surgical rehabilitation option, primarily chosen for esthetic and functional benefits, evidence on their use in patients with documented acrylic hypersensitivity remains lacking. The low quality and limited number of studies highlight the need for prospective, controlled, and long-term research to clarify the role of nylon prostheses in post-surgical oral rehabilitation and to define their effectiveness in patients with material allergies. Full article

Background: Despite advances in myoelectric control of hand prostheses, their dropout rate remains high. Methods: We analyzed 37 features extracted from surface electromyography (sEMG) recordings from 15 participants, distributed into three groups: non-impaired individuals, impaired individuals with limb loss due to trauma, and impaired individuals with limb loss due to electrical burn. Feature relationships were examined with correlation heatmaps and two feature-selection methods (ReliefF and Minimal Redundancy Maximum Relevance), and classification performance was evaluated using machine-learning models to characterize sEMG behavior across groups. Results: Individuals with electrical-burn injury exhibited increased forearm co-contraction on the affected side across normalized isometric contractions, indicating altered motor coordination and likely higher energetic cost for prosthetic control. Feature selection and model results revealed etiology-dependent differences in the most informative sEMG features, underscoring the need for personalized, etiology-aware myoelectric control strategies. Conclusions: These findings inform the design of adaptive prosthetic controllers and targeted rehabilitation protocols that account for injury-specific motor control adaptations. Full article

The loss of a limb is an event that significantly affects an individual’s quality of life, with implications not only for autonomy in daily activities but also for their ability to interact with others. At the same time, current prostheses often fail to meet the user’s needs, resulting in high drop-out rates. In this review, we investigated the primary causes of prosthesis abandonment and analyzed them by highlighting the technological and psychological aspects associated with current devices. Technological issues due to reliability, functionality and comfort, together with psychological issues related to anxiety and depression, are among the main factors contributing to prosthesis rejection. Social aspects, sport, and community activities play crucial roles in improving the sense of belonging and acceptance of prosthesis users. Although research has often prioritized functionality, prosthesis development should follow patient-centered models that address the individual needs and requirements of patients, emphasizing psychological, rehabilitative, and technological support. Full article

Background: Advancements in low-cost additive manufacturing and artificial intelligence have enabled new avenues for developing accessible myoelectric prostheses. However, achieving reliable real-time control and ensuring mechanical durability remain significant challenges, particularly for affordable systems designed for resource-constrained settings. Objective: This study aimed to design and validate a low-cost, 3D-printed prosthetic arm that integrates single-channel electromyography (EMG) sensing with machine learning for real-time gesture classification. The device incorporates an anatomically inspired structure with 14 passive mechanical degrees of freedom (DOF) and 5 actively actuated tendon-driven DOF. The objective was to evaluate the system’s ability to recognize open, close, and power-grip gestures and to assess its functional grasping performance. Method: A Fast Fourier Transform (FFT)-based feature extraction pipeline was implemented on single-channel EMG data collected from able-bodied participants. A Support Vector Machine (SVM) classifier was trained on 5000 EMG samples to distinguish three gesture classes and benchmarked against alternative models. Mechanical performance was assessed through power-grip evaluation, while material feasibility was examined using PLA-based 3D-printed components. No amputee trials or long-term durability tests were conducted in this phase. Results: The SVM classifier achieved 92.7% accuracy, outperforming K-Nearest Neighbors and Artificial Neural Networks. The prosthetic hand demonstrated a 96.4% power-grip success rate, confirming stable grasping performance despite its simplified tendon-driven actuation. Limitations include the reliance on single-channel EMG, testing restricted to able-bodied subjects, and the absence of dynamic loading or long-term mechanical reliability assessments, which collectively limit clinical generalizability. Overall, the findings confirm the technical feasibility of integrating low-cost EMG sensing, machine learning, and 3D printing for real-time prosthetic control while emphasizing the need for expanded biomechanical testing and amputee-specific validation prior to clinical application. Full article

Background: This scoping review systematically maps and synthesises contemporary literature on the biomechanics of active below-knee prosthetic devices, focusing on gait kinematics, kinetics, energy expenditure, and muscle activation. It further evaluates design advancements, including powered ankle–foot prostheses and variable impedance systems, that seek to emulate physiological ankle function and enhance mobility outcomes for transtibial amputees. Methods: This review followed the PRISMA-ScR guidelines. A comprehensive literature search was conducted on ScienceDirect, PubMed and IEEE Xplore for studies published between 2013 and 2023. Search terms were structured according to the Population, Intervention, Comparator, and Outcome (PICO) framework. From 971 identified articles, 27 peer-reviewed studies were found to meet the inclusion criteria between January 2013 and December 2023. Data were extracted on biomechanical parameters, prosthetic design characteristics, and participant demographics to identify prevailing trends and research gaps. This scoping review was registered with Research Registry under the following registration number: reviewregistry 2055. Results: The reviewed studies demonstrate that active below-knee prosthetic systems substantially improve gait symmetry and ankle joint range of motion compared with passive devices. However, compensatory trunk and pelvic movements persist, indicating that full restoration of natural gait mechanics remains incomplete. Metabolic efficiency varied considerably across studies, influenced by device design, control strategies, and user adaptation. Notably, the literature exhibits a pronounced gender imbalance, with only 10.7% female participants, and a reliance on controlled laboratory conditions, limiting ecological validity. Conclusions: Active prosthetic technologies represent a significant advancement in lower-limb rehabilitation. Nevertheless, complete biomechanical normalisation has yet to be achieved. Future research should focus on long-term, real-world evaluations using larger, more diverse cohorts and adaptive technologies such as variable impedance actuators and multi-level control systems to reduce asymmetrical loading and optimise gait efficiency. Full article

Objectives: Burn being a major traumatic issue worldwide impacts millions of lives annually. Herein, a novel xanthan dialdehyde/sodium alginate/copper-doped mesoporous bioactive glass nanoparticle (XDA/Na-ALG/Cu-MBGN) hydrogel is presented in this study. Methods: The hydrogel was fabricated by a casting method, followed by its characterization in terms of its morphology, surface topography, and in vitro biochemical and physical interactions. Results: Scanning electron microscopy images revealed the rough surface of the hydrogel, ideal for cell attachment and proliferation. The nanoporous structure revealed by BET enabled it to hold moisture for an extended span. The nanopores were developed because of the ether linkage developed between XDA and Na-ALG, as evident from Fourier Transform Infrared Spectroscopy. The loading of Cu-MBGNs was also confirmed by FTIR. The release of copper ions was sustained throughout the 7 days, and it is accounting for about 22 µg/mL in 330 h, which follows the degradation kinetics of XDA/Na-ALG/Cu-MBGN hydrogels. The released copper ions promoted angiogenesis, as confirmed by the enhanced release of vascular endothelial growth factor (VEGF) for the XDA/Na-ALG/Cu-MBGN hydrogel (275 ng/mL) in comparison to 200 ng/mL of the bare TCP. The hydrogel, despite being bactericidal against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) did not show toxicity towards human dermal fibroblasts confirmed via a Water-Soluble Tetrazolium 8 assay. Conclusions: Hence, the developed XDA/Na-ALG/Cu-MBGN hydrogel possesses potential to be investigated further in terms of in vivo interactions. Full article

Background: The need to improve gait emulation in people with amputation has driven the development of customized prosthetic mechanisms. This study focuses on the design and validation of a mechanism for external knee joint prostheses, based on the trajectory of the Instantaneous Center of Rotation (ICR) of a healthy knee. Objective: The objective is to design a mechanism that accurately reproduces the evolution of the ICR trajectory, thereby improving stability and reducing the user’s muscular effort. Methods: An exploratory methodology was employed, utilizing computer-aided design (CAD), kinematic simulations, and rapid prototyping through 3D printing. Multiple configurations of four- and six-bar mechanisms were evaluated to determine the ICR trajectory and compare it with a reference model obtained in the laboratory from a specific subject, using MATLAB-2023a and the Fréchet distance as an error metric. Results: The results indicated that the four-bar mechanism, with the incorporation of a simple gear train, achieved a more accurate emulation of the ICR trajectory, reaching a minimum error of 6.87 mm. Functional tests confirmed the effectiveness of the design in terms of stability and voluntary control during gait. It can be concluded that integrating the mechanism with the gear train significantly enhances its functionality, making it a viable alternative for the development of external knee prostheses for people with transfemoral amputation, based on the ICR of the contralateral leg. Full article

Objectives: The aim of this in vitro study was to evaluate the accuracy of intraoral impressions obtained using the Trios 3Shape^® (3Shape Trios, Copenaghen, Denmark) and Carestream CS 3600™ (Carestream Dental, Stuttgart, Germany) scanners, compared with traditional polyvinyl siloxane (PVS) impressions. A laboratory scanner served as the gold standard. Materials and Methods: The study was based on 3D-printed master models derived from partially edentulous clinical cases previously treated at our department (2017–2022). All cases required at least two implants. Data analysis was performed using one-way ANOVA and two-sample Z-tests (α = 0.05) to compare mean deviations and variability. Results: All techniques demonstrated high accuracy, with deviations from the reference point below 30 μm. The digital intraoral scanners (Trios 3Shape^® and Carestream CS 3600^®) showed superior accuracy compared with PVS analog impressions, with no statistically significant difference between the two IOS systems. Conclusions: Within the limitations of this in vitro study, both IOS systems and PVS analog impressions achieved clinically acceptable accuracy. Digital systems exhibited improved performance in terms of mean deviation and consistency. The higher accuracy and consistency of digital impressions may translate into improved clinical efficiency and prosthetic fit in implant rehabilitations. From a clinical perspective, these in vitro findings suggest that digital impressions may enhance prosthetic fit and workflow efficiency, though further in vivo validation is required. Clinical significance: This study supports the reliability of intraoral scanning compared with conventional impressions in implant-supported rehabilitations. By demonstrating high intrinsic accuracy, these findings contribute to optimizing digital workflows in implant dentistry and reinforce the potential of intraoral scanning in static computer-guided, flapless implant surgery. Trial registration: Ethical approval and trial registration were not applicable to the present in vitro investigation, as no patients were directly involved in the experimental phase. The digital data used to generate the laboratory master models originated from a separate clinical study conducted at ASST Santi Paolo e Carlo, Milan (Ethics Committee approval no. 1361, 12 July 2017; ClinicalTrials.gov registration, Unique Protocol ID 1361). Full article

Background: Screw loosening is considered a leading mechanical complication in implant-supported restorations. Hybrid abutments, combining a titanium base with a ceramic mesostructured, were proposed to enhance stability and esthetics. Objective: We aimed to evaluate screw-loosening behavior in implant-supported zirconia restorations fabricated with various abutment designs. Methods: Thirty-six implant analogs were divided into three groups: (A) a one-piece hybrid abutment crown, (B) a two-piece hybrid zirconia abutment with a separated crown, (C) and a stock abutment with zirconia crown. Restorations were fabricated with CAD/CAM, bonded using a dual cure resin cement, and torqued to 35 Ncm to the analogs. The initial removal torque (RTV1) was measured, followed by thermal cycling and mechanical loading (500 cycles, 120,000 load cycles). The post-aging removal torque (RTV2) was measured and the torque loss percentage was calculated. Paired t-tests, ANOVA, and Tukey’s test were used (p < 0.05). Results: All groups demonstrated significant torque loss following aging (p < 0.001). Group A showed the highest torque loss (12.0%), while Groups B and C exhibited lower loss (7.6% and 7.9%, respectively). The between-group difference was statistically significant (p < 0.001), except for between Groups B and C (p = 0.53). Conclusions: Within the limitations of this in vitro study, the abutment configuration affected screw preload stability. The one-piece hybrid abutment crown showed greater torque loss after aging, while the two-piece and stock abutment designs maintained comparatively better stability. Further clinical studies are required to confirm these findings. Full article

Background/Objectives: Artificial intelligence (AI) is increasingly embedded in CAD/CAM workflows to address persistent challenges in restorative dentistry, including unpredictable color outcomes and time-intensive crown design steps. Yet, evidence on its accuracy and efficiency remains fragmented across heterogeneous study designs and metrics. This systematic review and meta-analyses aimed to evaluate the accuracy and performance of AI for color prediction and automated crown design in CAD/CAM ceramics. Methods: A systematic review with random-effects meta-analyses. The outcomes included design time, internal fit, finish-line accuracy, color-prediction acceptability using ΔE₀₀ (AT₀₀), morphology deviation, and occlusal and proximal contacts. Results: Fifteen studies met the inclusion criteria. The meta-analyses showed that AI-equipped CAD reduced crown design time compared to conventional CAD (MD −88.7 s; 95% CI −134.5 to −42.9; I² = 72%). The internal fit showed a small advantage for AI (MD −17.1 µm; 95% CI −26.2 to −7.9; I² = 90%). For finish-line identification, the pooled mean Hausdorff distance was ~0.35 mm (95% CI 0.316–0.382; I² = 0%). For color prediction, the pooled proportion of predictions within each study’s prespecified acceptability threshold (AT₀₀) was near-universal (0.996; 95% CI 0.988–0.999; I² = 0%). Morphology and functional contacts were not pooled due to incompatible metrics and units. Narrative synthesis indicated AI performance comparable to, or favorable over, conventional/technician workflows in selected regions. Conclusions: AI for CAD/CAM dentistry shows practical promise, most clearly for design-time efficiency and with encouraging signals for internal fit, finish-line identification, and color-prediction acceptability under study thresholds. However, clinical translation should proceed cautiously. Full article

Background/Objectives: The precision and bonding reliability of space maintainers are critical to their clinical success longevity. This study aimed to evaluate and compare the fit accuracy and shear peel bond strength of digitally fabricated space maintainers—cobalt–chromium (Co-Cr) and polyetheretherketone (PEEK)—against conventional space maintainers. Methods: Seventy-eight space maintainer bands were fabricated—milled PEEK, selective laser-melted (SLM; an additive manufacturing technique) Co-Cr, and conventional stainless steel (SS)—and tested. Fit accuracy was evaluated on 39 bands by measuring the root mean square (RMS) deviation from a master model using digital 3D analysis. Shear peel bond strength (SPBS) was tested on another 39 samples using a universal testing machine, and the adhesive remnant index (ARI) was recorded after debonding. Statistical analyses included a Welch ANOVA for fit accuracy and the Kruskal–Wallis test for the SPBS test; the ARI was analyzed using Fisher’s exact test (significance level p < 0.05). Results: Digitally fabricated bands demonstrated significantly higher fit accuracy than the stainless steel bands (mean RMS deviation: Co-Cr = 0.151 mm, PEEK = 0.152 mm, SS = 0.344 mm; p < 0.001). Co-Cr and PEEK demonstrated comparable adaptation. In contrast, bond strength was significantly greater in Co-Cr (1.657 MPa) and SS (1.481 MPa) compared to PEEK (0.393 MPa). ARI distribution varied significantly across the three groups. Conclusions: Both milled PEEK and Co-Cr bands demonstrated excellent adaptation compared with conventional SS bands. However, Co-Cr exhibited reliable bonding performance, yet PEEK may require additional surface treatment or bonding optimization to enhance adhesion. Full article

Background: This study evaluated the influence of various decontamination protocols after salivary contamination on the micro-shear bond strength (µSBS) between monolithic high-translucency zirconia and resin cement. Methods: A total of 81 multilayer (ML) monolithic–translucent zirconia discs of 10 mm diameter and 2 mm thickness (DD cubeX2 ML, Dental Direkt) were fabricated, sintered, and polished using silicon–carbide papers. The bonding surfaces were treated with 50-μm Al₂O₃ using a Renfert sandblaster at 0.3 MPa for 20 s. Fifty samples were randomly assigned to five groups (n = 10). A control group consisted of clean, uncontaminated samples, while the other four groups were contaminated and cleaned using water, sodium hypochlorite, phosphoric acid + ethanol, or Ivoclean, respectively. Resin cement cylinders (Panavia V5, Kuraray Noritake) were bonded onto the zirconia surfaces. The µSBS was evaluated after simulated ageing using a universal testing machine. Failure modes were analysed by light microscopy. Surface morphology was evaluated using a field emission scanning electron microscope (SEM), and the chemical surface was assessed with X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared (FTIR) Spectroscopy. Surface wettability was assessed through contact angle measurements. One-way ANOVA with Tukey’s HSD was used to compare µSBS between groups. Results: Among the tested groups, the control group exhibited the highest µSBS value (59.5 ± 4.2 MPa), followed by Ivoclean (56.7 ± 4.8 MPa), phosphoric acid + ethanol (46.8 ± 4.7 MPa), and sodium hypochlorite (41.1 ± 5.7 MPa), with the lowest value observed with water (33.5 ± 6.3 MPa). All groups exhibited adhesive failure, with no sign of cohesive or mixed failures. SEM analysis showed no effect on zirconia crystallinity or sandblasting, while Ivoclean left residual zirconium oxide particles. Furthermore, XPS and FTIR analysis revealed favourable chemical changes after Ivoclean treatment, correlating with improved bonding performance. Contact angle measurements confirmed greater surface wettability in the Ivoclean group, resulting in strong bond strength. Conclusions: Ivoclean significantly increased the resin–zirconia bond strength after saliva contamination, showing more reliable results compared to others. Phosphoric acid + ethanol showed the second-highest mean strength, while water showed the least effectiveness. Full article

Background/Objectives: Stability, retention, and support are removable partial denture (RPD) biomechanical principles. The literature shows contradictory opinions on indirect retention in RPDs, but no solid scientific evidence exists. This in vitro research aims to analyze indirect retainers’ (IRs) influence on forces transmitted to abutment teeth of a Kennedy Class I mandibular RPD. Methods: Bilateral distal-extension mandibular RPDs—differing only in the presence or absence of an IR on tooth 44 (IR model vs. nonIR model, respectively)—were installed on an acrylic master model. Tensile forces were applied perpendicularly to the occlusal plane on the longest free-end saddle’s distal aspect. Electronic speckle pattern interferometry (ESPI) measurements were obtained with and without an IR. The three-dimensional out-of-plane displacements of both models were acquired. Results: Abutment teeth 46 and 47 contralateral to the longest distal extension suffered more deformation under displacement forces when an IR was used. In turn, the IR’s influence on the deformation values of the abutment tooth 34 adjacent to the larger edentulous area depended on the intensity of the tensile force exerted: low-intensity forces resulted in reduced deformation, while higher-intensity forces resulted in higher deformation. Conclusions: This study’s findings indicate that indirect retention promotes better tensile force distribution in the existent teeth. However, they also question the IR’s role in protecting abutment teeth against excessive torque forces. This study’s preliminary results highlight the need for research on indirect retention principles using new methodologies, namely, in silico and ex vivo studies, and their experimental and clinical validation. Full article

Background: Gastroesophageal reflux disease (GERD) exposes restorative materials to gastric acid, which may compromise their esthetic and optical properties. Limited evidence exists regarding the performance of different CAD/CAM ceramics under acidic challenges. Methods: Forty CAD/CAM ceramic discs were prepared (n = 10 per group): high-translucency zirconia (Z; Ceramill Zolid Gen-X), lithium disilicate (E; IPS e.max CAD), zirconia-reinforced lithium silicate (S; VITA Suprinity), and hybrid ceramic (C; Cerasmart 270). Specimens were immersed in simulated gastric acid (0.06 M HCl, pH 1.2) at 37 °C for 96 h. Color difference (ΔE) and translucency parameter (ΔTP) were recorded before and after immersion using a spectrophotometer. Data were analyzed using one-way ANOVA with Tukey’s post hoc test (α = 0.05). Results: All materials exhibited changes in color and translucency after acidic immersion. Group Z demonstrated the lowest ΔE values, indicating the best color stability, whereas group C showed the highest ΔE and a significant reduction in ΔTP. Groups E and S revealed moderate but clinically acceptable changes. Intergroup differences were statistically significant (p < 0.05). Conclusions: Exposure to simulated gastric acid as in (GERD) resulted in measurable alterations in the optical properties of CAD/CAM ceramic materials. The extent of color change and translucency loss differed among the materials tested. High-translucency zirconia (Z) exhibited the greatest stability, while hybrid ceramic (C) showed the most pronounced changes. Zirconia-reinforced lithium silicate (S) and lithium disilicate (E) demonstrated moderate alterations, falling between these two extremes. Full article

Objectives: This in vitro study aimed to evaluate the effects of three framework orientation (FO) positions on an SLM building platform (Horizontal [H], Diagonal-45° [D45°], Diagonal-60° [D60°]) and two designs (with [B] or without [NB] stabilizing bars) on the fitting accuracy of digitally fabricated Co-Cr RPD frameworks. Materials and Methods: A custom RPD framework CAD was performed on a 3D-printed resin-model of an edentulous maxilla with three geometric tooth forms. A Co-Cr alloy was processed via SLM processing into 24 framework specimens, divided into three FO groups (n = 8: H, D45°, D60°) and two subgroups each (n = 4: B, NB). Qualitative/quantitative fit-evaluation was assessed using virtual framework-to-model seating and a custom digital protocol with GOM Inspect software (2018-Hotfix5, Rev.115656). Mean fitting distances were calculated from 220 equidistant points per specimen. Statistical comparisons were performed using ANOVA-on-ranks, Kruskal–Wallis multiple comparisons, and Bonferroni adjustment. Results: FO Sub-Group medians (Q1, Q3: 25% and 75% Quartiles) (mm) were: H/NB 0.150 (0.140, 0.164), H/B: 0.136 (0.121, 0.152), D45°/NB: 0.230 (0.219, 0.241), D45°/B: 0.144 (0.137, 0.154), D60°/NB:0.238 (0.232, 0.247), D60°/B: 0.171 (0.166,0.176). Pairwise comparisons indicated the following statistically significant (p < 0.05) FO Sub-Group differences: H/B-D45°/NB, H/B-D60°/NB, D45°/B-D45°/NB, D45°/B-D60°/NB, H/NB-D45°/NB, H/NB- D60°/NB. Conclusions: Horizontal orientation improved RPD fit accuracy regardless of bar presence. D45° accuracy is enhanced by stabilizing bars, while D60° accuracy is unaffected by bar addition. Full article

Background: Material choice in full-arch implant-supported restorations significantly impacts longevity, complication rates, and patient satisfaction. This retrospective study compared monolithic zirconia versus hybrid metal–ceramic full-arch designs over a minimum three-year follow-up. Methods: Twenty patients (9 female, 11 male; mean age 55.4 ± 7.5 years) treated with full-arch implant-supported restorations were reviewed. Ten received monolithic zirconia restorations; ten received hybrid metal–ceramic. Clinical outcomes, including mechanical complications, prosthetic maintenance needs, opposing dentition wear, and patient-reported satisfaction (esthetics, comfort, masticatory function via VAS), were recorded. Statistical analyses were performed using Chi-square, independent t-tests, or Mann–Whitney U tests, with a significance level set at p < 0.05. Results: All implants (100%) and prostheses (>95%) survived. Monolithic zirconia exhibited no veneering chipping, while two events were observed in hybrid restorations (difference not statistically significant), and one bulk fracture occurred (monolithic). Hybrids had no framework fractures. Screw loosening occurred in one zirconia case. Mean VAS scores exceeded 9.0 in both groups; zirconia scored slightly higher for esthetics (9.4 ± 0.5 vs. 8.8 ± 0.6) and comfort (9.2 ± 0.6 vs. 9.0 ± 0.7). Polished zirconia resulted in no clinically detectable enamel wear, whereas hybrids with glaze loss caused occasional mild enamel wear but without functional impairment. Conclusions: Both restoration types show excellent survival and patient satisfaction over three years. Monolithic zirconia reduces veneering-related complications and maintenance, suggesting a possible advantage in functionally demanding cases with high occlusal loads or limited prosthetic space; hybrids may remain preferable when esthetic customization and gingival contour reproduction are paramount. Full article

Limb amputation is a growing health concern worldwide, driven largely by the rising incidence of vascular and metabolic diseases and military conflicts. In the past two decades, remarkable advancements in surgical techniques, prosthetic technologies, and rehabilitation strategies have made a profound impact on outcomes for individuals with limb loss. In this article, we explore the evolving landscape of limb care in the United States, highlighting innovations in prosthetic technology and amputation surgery including osseointegration, neuromuscular surgeries and interfaces, artificial intelligence, sensory feedback, and the importance of prosthetic embodiment. We discuss limb care systems and the continuum of limb loss rehabilitation, focusing on the need for coordinated models of patient-centered care. We present the demographic biases and healthcare disparities related to insurance coverage and reimbursement in the United States and the explore ethics and equitability considerations pertaining to prosthetic standard of care and advanced treatments for limb loss. Finally, we lay out the systemic reform, policy advocacy, and future research needed to ensure that everyone with limb loss has equitable access to the benefits of modern amputee care. Full article

Background: Culture-negative periprosthetic joint infections (PJIs) are dramatically increasing in prevalence. The success rate of implant-saving procedures in acute PJI cases is closely correlated with prompt diagnosis, rapid isolation/identification of the microorganism, and timely surgical intervention. Methods: A 70-year-old female patient with an acutely infected left total hip arthroplasty (THA) following a routine screening colonoscopy was rapidly treated with debridement, antibiotic pearls, and retention of the implant (DAPRI) after rapid identification of the microorganism using a molecular diagnostics-based algorithm. Results: Molecular diagnostics enabled the identification of Escherichia coli as the causative agent of the transient bacteremia and subsequent seeding of the left hip within less than an hour. Conclusions: This case suggests that endoscopic procedures may increase the risk to joint replacement patients. In acute PJI, the use of molecular diagnostics, which facilitates prompt identification of microorganisms, may increase the success rate of implant-saving surgical procedures. Full article

Background/Objectives: Achieving durable intraoral repairs of fractured metal and zirconia restorations requires optimal adhesion. This in vitro study evaluated the effects of mechanical surface treatments and commercial repair systems on the shear bond strength (SBS) of composite resin to nickel–chromium (Ni-Cr) alloy and zirconia, including the influence of thermocycling aging. Methods: In this study, 144 Ni-Cr and zirconia discs (12 × 12 × 2 mm) were randomly assigned to three surface treatments: untreated control, airborne particle abrasion (50 µm Al₂O₃), and medium grit diamond bur grinding. Each group was further subdivided to assess two intraoral repair kits (GC Corp (Tokyo, Japan). and Bisco Inc. (Schaumburg, IL, USA)). Composite resin cylinders were bonded following the manufacturer’s instructions. Half of the specimens (n = 12/subgroup) underwent 5000 thermocycles (5–55 °C). Micro-shear bond strength testing was performed, and failure modes were analyzed. Data were analyzed using three-way ANOVA and post hoc tests (p < 0.05). Results: Air abrasion significantly increased SBS compared to control and bur grinding for metal (p < 0.001). For zirconia, both air abrasion and bur grinding yielded similarly improved SBS over the control (p < 0.001). The GC repair kit demonstrated significantly superior bond stability after thermocycling across both substrates. Aging significantly reduced SBS in all groups (p < 0.001), with the most substantial reductions observed in untreated controls and groups repaired with the Bisco system. Conclusions: Airborne particle abrasion combined with a HEMA-free, 10-MDP-containing universal adhesive achieved the strongest and most durable resin bonds to both metal and zirconia, supporting its clinical use for the intraoral repair of ceramic and metal restorations. Full article

Background/Objectives: This study aims to investigate the stress distribution and deformation of cobalt–chromium (CoCr) and polyetheretherketone (PEEK) maxillary bilateral distal-extension removable partial dentures (RPDs) on the abutment, periodontal ligament (PDL), mucosa, and RPD framework. Methods: A three-dimensional maxilla model was obtained from the patient’s cone-beam computed tomography (CBCT) and master model scan, composed of six maxillary anterior teeth, and U-shaped palatal major connectors for both the CoCr and PEEK RPD designs were constructed with computer-aided design (CAD) using the software program SolidWorks 2017 (SolidWorks Corp., Waltham, (MA), USA). A total vertical force of 320 N was applied bilaterally to the posterior artificial teeth. Three-dimensional finite element analysis was applied to evaluate the von Mises stress (VMS) distributions of the CoCr and PEEK RPDs on the abutment, PDL, mucosa, and RPD framework, and the deformation of the RPD framework was analyzed using ANSYS Workbench software, version 2020 (ANSYS Workbench 2020; ANSYS Inc.). Results: The stress distribution originated from the RPD free-end and was distributed to the mucosa, abutment, and PDL. The maximum stress observed in the oral structures was highest at the abutment, followed by the mucosa and PDL. The VMS occurring at the abutment in the CoCr RPD (9.098 MPa) was higher than that at the PEEK RPD (7.515 MPa), while the VMSs occurring at the mucosa and PDL in the CoCr RPD and PEEK RPD were similar. RPD frameworks constructed from different materials generated different stress distribution patterns. The maximum VMS occurring in the CoCr RPD framework (107.99 MPa) was significantly greater than that at the PEEK RPD framework (11.7 MPa). Meanwhile, the maximum deformation in the vertical direction of the PEEK RPD framework (0.0128 mm) was higher than that of the CoCr RPD framework (0.0082 mm). Conclusions: The results suggested that the PEEK RPD may have a better protective effect on the abutment. Both the PEEK and CoCr RPDs were unlikely to cause severe mechanical damage to the mucosa and PDL. However, the thickness of the PEEK framework should be focused on to reduce the stress distribution to the residual ridge mucosa. Full article

Background/Objectives: Silicone elastomers are widely used in maxillofacial prostheses, but their service life is typically limited to 6–24 months due to progressive degradation. Reinforcement with zirconium silicate (ZrSiO₄) nanoparticles has been proposed to improve durability, yet evidence on their long-term performance under storage remains limited. This study evaluated the effect of two years of dark storage on the mechanical properties of room-temperature-vulcanized (RTV) silicone reinforced with 1.5 wt% ZrSiO₄ nanoparticles. Materials and Methods: Zirconium silicate (ZrSiO₄) nanoparticles at 1.5 wt% were incorporated into A-2186 RTV silicone specimens, which were randomly divided into two equal groups: baseline specimens stored for 24 h and aged specimens stored for 24 months under dark conditions. Mechanical properties were assessed by measuring tensile strength, elongation at break, tear resistance, and Shore A hardness in accordance with standardized protocols. Fourier transform infrared (FTIR) spectroscopy was performed to verify the structural characteristics of the ZrSiO₄ nanopowder. Statistical analysis was conducted using independent-samples t-tests, with significance set at p < 0.05. Results: After 24 months of dark storage, tensile strength and elongation at break decreased significantly (p < 0.05), indicating reduced elasticity. Tear resistance and hardness showed slight but non-significant reductions. FTIR confirmed the preservation of ZrSiO₄ structural features. Conclusions: Dark storage selectively reduced reinforced silicone’s tensile and elongation properties, while tear resistance and hardness remained relatively stable. ZrSiO₄ nanoparticles provided partial reinforcement, enhancing stability but not entirely preventing RTV silicone aging. Full article

Background/Objectives: The present study investigated the effects on the mechanical and physical properties of PMMA when organoselenium was incorporated into it as antifungal at different concentrations. Methods: 141 PMMA rectangle samples were fabricated using a heat compression packing technique and assigned to 3 experimental groups (47/group): 0% organoselenium (control), 0.5% organoselenium (0.5% SE), and 1% organoselenium (1% SE). Each sample was post-processed and stored in water. A three-point bend test was performed to assess elastic modulus and flexural stress. Scanning electron microscopy (SEM) was used to examine the exterior and interior surface topography. Data were analyzed using one-way ANOVA with Tukey’s multiple comparisons test. Results: The mean flexure stress for the 0% samples was statistically significantly higher than those of the 0.5% samples and the 1% samples (p < 0.001). The mean elastic modulus for the 0% group was statistically significantly higher than those of the 0.5% group and the 1% group (p < 0.001). Under SEM, the 0.5% samples were smoother with fewer voids and irregularities. Conclusions: The incorporation of organoselenium into PMMA denture base negatively affected its physical and mechanical properties. Full article

Background/Objectives: The marginal adaptation of CAD/CAM restorations remains a key determinant of long-term clinical success, particularly in minimally invasive preparations. This in vitro study evaluated and compared the marginal gap of three CAD/CAM restorative materials—Cerasmart, G-CAM, and IPS Empress CAD—using standardized preparation and SEM measurement protocols. Methods: A total of 18 crowns were fabricated, of which 9 presented margins sufficiently interpretable under SEM and were included in the pooled quantitative analysis (n = 362 measurement points). Marginal gaps were recorded at 45×, 100× and 450× magnification using a Jeol JSM 25S scanning electron microscope. Normality and variance homogeneity were verified prior to parametric testing. Results: When pooled per material group, the mean ± SD marginal gap values were 18.53 ± 14.15 µm for Cerasmart, 21.60 ± 14.89 µm for G-CAM, and 47.09 ± 16.93 µm for IPS Empress CAD. All values fell below the contemporary clinical threshold of <70 µm for adhesive cementation. Pairwise comparison showed a large difference between IPS Empress CAD and the two resin-based materials, whereas the difference between Cerasmart and G-CAM was small. Conclusions: Hybrid and resin nano-ceramic CAD/CAM materials demonstrated narrower marginal gaps compared with the glass ceramic tested, likely due to their lower elastic modulus and greater seating accommodation during cementation. Within the limits of this in vitro design, all materials exhibited marginal adaptation consistent with current clinical acceptability criteria. Full article

Background: Subcrestally placed implants (SPIs) present advantages for bone preservation and soft tissue support but pose challenges in maintaining peri-implant soft tissue health. This case explores the role of Crest to Restoration Distance (CRD) in the development and resolution of peri-implant mucositis. Case Presentation: A 57-year-old woman received two SPIs—one in the upper left and one in the lower right first molar region. Despite similar implant systems and prosthetic protocols, the upper left implant developed mucositis, characterized by bleeding on probing and discomfort, while the lower right implant remained stable. Three-dimensional analysis using cone-beam computed tomography (CBCT) revealed excessive CRD at the affected site. Results: After prosthodontic revision to reduce the CRD, clinical signs of mucositis resolved, with probing depths reduced to less than 1 mm and no bleeding on probing. The control site remained healthy throughout the observation period. Practical Implications: This case highlights CRD as a modifiable prosthetic factor influencing soft tissue stability. A three-zone model—comprising the sulcus, transitional zone (TZ), and subcrestal zone (SZ)—is introduced to provide a biologically grounded framework for understanding soft tissue adaptation around SPIs. Full article

Ceramic dental implants, particularly one-piece zirconia, offer a biocompatible and aesthetic alternative to titanium, with high strength and improved oral hygiene. By eliminating the implant–abutment micro-gap, they reduce bacterial accumulation because of their low plaque affinity and enhance stability. However, challenges remain, including alignment precision, limited retrievability, and sensitivity to mechanical stress. Misalignment can affect occlusal and functional outcomes, and zirconia’s rigidity complicates crown removal and modification. This case report explores the use of PEEK (polyether ether ketone) primary telescopic crowns to overcome these limitations, improving force distribution, enabling minor adjustments, and enhancing prosthetic retrievability in full-mouth zirconia restorations. A 62-year-old male patient seeking a fixed solution to replace removable dentures received 16 one-piece zirconia implants (eight per jaw). PEEK telescopic crowns were used over implant abutment copings, finalized with aesthetic zirconia bridges. The report details surgical and prosthetic procedures, along with a brief literature review on zirconia implants and PEEK applications. PEEK integration in telescopic prosthetic designs marks a notable advancement in prosthodontics. Its shock-absorbing, biocompatible, and stress-modulating properties make it valuable for implant-supported and hybrid restorations. As digital workflows advance, PEEK-based telescopic restorations may increasingly replace traditional metal-based solutions, improving long-term clinical outcomes. Further clinical research on a larger sample is needed. Full article

Purpose: This study investigates the static mechanical behavior of a non-modular metallic hip prosthesis through Finite Element Method (FEM) simulations, assessing compliance with ASTM F2996-13 standards. The analysis specifically evaluates how key geometric parameters, such as trunnion extension and orientation angles (adduction and flexion), affect stress distributions within the prosthesis. Methodology: A three-dimensional finite element model of a Ti6Al4V alloy hip stem was developed. Boundary and loading conditions were defined according to the standard: the distal portion of the stem was fully constrained 90 mm below the head center, and a static load of 2300 N was applied at the head center along the directions defined by the adduction and flexion angles. A mesh sensitivity analysis was conducted to ensure convergence, and stresses were evaluated. Parametric analyses varying trunnion extension and orientation angles were performed to quantify their impact on local stress concentration. Results: The findings revealed that even minor deviations in the adduction and flexion angles significantly impact the stress distribution, with the potting-level region being particularly sensitive. Additionally, the extension of the trunnion led to notably increased stress concentrations, especially at the prosthesis neck, highlighting its critical influence in implant design. Conclusions: Comparison with existing literature and standard reference data exposed discrepancies primarily attributed to variations in FEM model setups and parameter selections. This emphasizes the necessity of clearly specifying trunnion extension and orientation angles in numerical analyses to ensure consistent stress predictions, supporting the development of safer and longer-lasting hip implants. Future research should extend these analyses to different prosthesis geometries, aiming to develop generalized predictive frameworks applicable to diverse biomechanical scenarios. Full article

Plasma surface modification has emerged as a powerful, versatile tool for tailoring the surface properties of biomedical devices and implants without altering the material characteristics in the bulk. This comprehensive review critically examines the current state-of-the-art in plasma-based surface engineering techniques, with a focus on enhancing biocompatibility, bio-functionality, and long-term performance of medical implants. The article systematically explores various plasma processes and their roles in modifying surface chemistry, topography, energy, and wettability. These alterations directly influence protein adsorption, cell adhesion, antibacterial activity, and corrosion resistance, all of which are crucial for successful clinical integration. Special emphasis is placed on the plasma treatment of metallic (e.g., titanium, stainless steel), polymeric (e.g., polytetrafluoroethylene, polyetheretherketone), and composite substrates commonly used in dental, orthopedic, and cardiovascular applications. This review also highlights synergistic strategies, such as plasma-assisted grafting of bioactive molecules and nanostructuring, that enable multifunctional surfaces capable of promoting osseointegration, mitigating inflammation, and preventing biofilm formation. Emerging trends such as atmospheric cold plasmas and the integration of plasma technology with additive manufacturing are outlined as promising future directions. By synthesizing insights from surface science, materials engineering, and biomedical research, this review provides a foundational framework to guide future innovations in plasma-treated biomaterials. It aims to inform both academic researchers and medical device developers seeking to optimize implant–tissue interactions and achieve improved clinical outcomes. Full article

Background: Tooth development or odontogenesis is a complicated, multi-staged process, regulated by a plethora of genes. Disruptions during the early stages of odontogenesis may cause the complete absence of one or more teeth, known as tooth agenesis (TA). Except for PAX9, alterations in MSX1, AXIN2, WNT10A, and EDA/EDAR/EDARADD have gathered an increasing amount of interest. Objectives: This systematic review aims to investigate whether non-syndromic tooth agenesis (NSTA) is associated with MSX1, AXIN2, WNT10A, and EDA/EDAR/EDARADD mutations and to list the related phenotypic patterns of these alterations with regard to missing teeth. Methods: MEDLINE, Scopus, and Web of Science were the three selected databases. Duplicates were removed using Mendeley, and the records were assessed via the Rayyan platform. The Newcastle–Ottawa Scale was used to evaluate the quality of the evidence. Results: Fifteen case–control studies were eligible for this systematic review. The MSX1 gene was examined in most studies, whereas second premolars and lateral incisors were the most commonly missing teeth among TA cases. In total, 61.29% to 84.9% of the cases included one or two absent teeth. Conclusions: Due to the considerable heterogeneity in reporting results across the included studies, along with the high risk of bias present in most of them, it was not feasible to conduct a meta-analysis of the data. Nonetheless, the findings suggest that the NSTA phenotypes linked to the studied genes are similar to those associated with other forms of TA and share a common pattern of missing teeth. Future research should adopt a more standardized approach in presenting findings by adhering to established terminology and definitions and by utilizing common cut-off points to categorize results. Full article

Objective: The Ti6Al4V titanium alloy is widely used for dental implants because of its excellent mechanical properties, corrosion resistance, and biocompatibility. However, its bioinert surface limits both osseointegration and resistance to bacterial colonization. Methods: To address these challenges, this study develops a composite coating based on calcium phosphate (CaP) and silver (Ag), reinforced with zirconium oxide (ZrO₂). The coating was deposited on Ti6Al4V using an immersion technique to improve the surface properties of the alloy. Electrochemical analyses (OCP, EIS, and potentiodynamic polarization) were performed in simulated physiological conditions to evaluate the corrosion behavior, while SEM/EDS was used to characterize the surface morphology and composition. Results: The Ag- and Zr-containing CaP coatings significantly improved the corrosion resistance of Ti6Al4V compared with uncoated and CaP-coated samples. Conclusions: This approach provides a promising strategy to enhance the electrochemical stability and long-term durability of titanium dental implants, thereby contributing to their reliable performance in the oral environment. Full article

Background/Purpose: Teeth prepared for fixed dental prostheses are subject to various types of insults in the oral cavity. Therefore, to protect the tooth, the pulp, and supporting structures, provisional restorations are mandatory. Our study aimed to evaluate the knowledge and clinical practices regarding provisional fixed dental prostheses (PFDPs) among dental professionals in Saudi Arabia. Materials and Methods: A cross-sectional study based on a self-administered online survey was conducted among 312 dentists (general practitioners and specialists) across Saudi Arabia. The questionnaire assessed participants’ knowledge (11 items) and clinical practices (9 items) related to PFDPs. Statistical analyses included descriptive statistics, chi-square tests, and multivariate logistic regression. Results: Only 46.5% of respondents demonstrated adequate knowledge of PFDPs. Knowledge was significantly higher among specialists than general practitioners (57.4% vs. 41.7%, p = 0.011), and specialists were more likely to recognize the influence of PFDPs on treatment outcomes. Clinical practice patterns indicated that even though 94.2% of respondents frequently placed PFDPs, only 66.0% always did so. Moreover, 21.2% of respondents rarely or never disinfect PFDPs. Public sector dentists and specialists were more likely to use custom-made PFDPs. Key gaps in knowledge were observed regarding the materials and equipment used in the fabrication of PFDPs, particularly concerning CAD/CAM technology. Conclusions: Although most dentists in Saudi Arabia provided PFDPs to their patients, significant gaps remain in their knowledge, particularly regarding fabrication materials and techniques. Targeted educational interventions, especially for general practitioners, are needed to enhance clinical outcomes. Full article