Prosthesis, Volume 8, Issue 8 (August 2026) – 9 articles

Background: Lower limb exoprostheses often lead to stump dermatological pathologies. The mechanisms by which mechanical microtraumas progress to non-healing ulcerative defects due to dysbiosis remain poorly understood. The objective of this study was to analyze mechanical, inflammatory, and infectious stump skin complications and justify the role of bacterial and mycological dysbiosis in blocking tissue regeneration. Methods: A critical narrative review guided by SANRA principles was conducted (PubMed/Scopus, 1980–2026). Data were extracted with a structured query focusing on amputation stumps, prosthetic interfaces, and skin/microbiological complications (dysbiosis, biofilms, and inflammatory markers). Evidence was graded using predefined clinical matrices and integrated through structured evidence collations to synthesize stump–prosthesis pathogenesis. The PRISMA method was not applied due to study heterogeneity. Results: Skin damage dynamics were categorized into three stages: adaptation (up to 12 months), chronic reactive changes (12–24 months), and late proliferative-infectious destruction (>24 months). The sealed liner space creates 100% humidity and alkalization (pH > 6.5). This causes a mycological shift, where resident Malassezia spp. lose dominance to invasive Candida albicans and non-dermatophyte molds (Aspergillus spp., Fusarium spp.). These pathogens form polymicrobial biofilms with Staphylococcus aureus. At the molecular level, delayed regeneration is driven by “frustrated phagocytosis”: macrophages, unable to engulf large fungal hyphae, continuously release reactive oxygen species and enzymes, trapping the wound in the inflammatory phase. Excessive matrix degradation and suppressed angiogenic factors further block epithelialization. Conclusions: The skin under a prosthesis socket forms a unique pathological biotope. Successful regeneration requires preventive mycobiota correction and targeted management of biophysical parameters (pH, humidity) within the “skin–liner” interface. Full article

Background/Objectives: Studies consistently demonstrate that microprocessor-controlled prosthetic knees (MPKs) improve mobility and quality of life for people with lower limb loss or absence by enhancing balance and reducing falls. However, the extent to which these benefits apply across demographic groups remains unclear. Therefore, we conducted a literature review to evaluate how representative and transferable research on MPKs is across different populations, and which factors influence this. Methods: Using systematic review principles and PRISMA guidelines, 27 studies were analysed from databases including Cochrane, CINAHL, MEDLINE, and PubMed, as of 20th September 2025. The included studies primarily focused on young-to-middle-aged adults, men, individuals with trauma-related amputation, and higher mobility levels. Results: We found that older adults, women, and individuals with amputation caused by vascular disease or diabetes were under-represented in MPK research. Moreover, variability in time since amputation complicates the generalisability of findings, as this factor significantly influences adaptation and functional outcomes. Conclusions: While evidence supports MPKs’ effectiveness in enhancing mobility and reducing the risk of falls, their benefits may not fully apply to under-represented groups, such as older adults, women, or low-activity users. Future research should prioritise more diverse participant samples to improve the generalisation of MPK outcomes across different demographics and functional levels. Full article

Background: Accurate reproduction of subgingival finish lines remains a major challenge in fixed prosthodontics. This scoping review aimed to map and synthesize current evidence comparing digital and conventional impression techniques for tooth-supported restorations with subgingival margins. Methods: The review followed the Arksey and O’Malley framework and was reported in accordance with PRISMA-ScR guidelines. Four electronic databases (PubMed, Scopus, Web of Science, and Google Scholar) were searched for English-language studies published between 2005 and 2025. Eligible studies included both in vitro and in vivo investigations evaluating impression techniques in subgingival conditions. Results: A total of 51 studies were included, of which 66.6% were in vitro. Digital scanning accuracy decreased consistently as subgingival depth increased, particularly beyond approximately 1 mm below the gingival margin. Conventional elastomeric impressions generally demonstrated more consistent reproduction of deeper subgingival margins. Conclusions: Impression accuracy in subgingival conditions appears to depend primarily on finish line depth and clinical conditions rather than on impression modality alone. Digital workflows appear reliable for equigingival and shallow subgingival margins, whereas conventional or hybrid approaches may remain advantageous in deeper subgingival scenarios. Further well-designed in vivo studies using standardized measurement protocols are needed to support evidence-based clinical recommendations. Full article

Background/Objectives: Injection moulding has become a predictable technique for transferring a diagnostic wax-up to direct composite restorations. However, conventional workflows that rely exclusively on injectable flowable composites may have limitations in material handling, mechanical performance, and the dimensional stability of the transparent silicone index. The purpose of this technical note was to describe a silicone-guided modification of the injection moulding workflow, referred to as the compression moulding technique, and to illustrate its clinical application in three representative cases. Methods: The proposed workflow combines a dual-layer silicone index consisting of a transparent polyvinyl siloxane material supported by a high-hardness bite-registration silicone with a preheated medium-viscosity resin composite. Following digital planning and diagnostic wax-up, the composite is positioned within the silicone index and adapted to the prepared tooth surfaces by controlled compression. Three clinical cases with different restorative indications were included to demonstrate the technique’s versatility. Results: In all three cases, the proposed workflow enabled accurate transfer of the diagnostic wax-up while providing improved stabilization of the transparent silicone index during composite placement. The combination of controlled compression, a rigid supporting silicone, and preheated paste composite facilitated material adaptation, minimized manual sculpting, and produced predictable esthetic outcomes in a minimally invasive chairside procedure. Conclusions: The compression moulding technique represents a practical modification of the conventional injection moulding workflow for direct composite restorations. The proposed protocol may improve index stability, material handling, and clinical versatility while maintaining the advantages of silicone-guided restorative procedures. Because the present article is intended to describe a technical workflow supported by representative clinical cases, further prospective clinical studies with long-term follow-up are required before conclusions regarding clinical superiority or long-term performance can be drawn. Full article

Background/Objectives: To compare the effects of different surface treatments on the color and translucency of three types of zirconia ceramics. Methods: Ninety CAD/CAM-milled zirconia disks (10 mm diameter, 1 mm thickness) were fabricated from Cercon HT (3-YTZP), IPS e.max ZirCAD MT (4-YTZP), and Cercon XT (5-YTZP). Baseline CIE Lab* coordinates were measured using a digital spectrophotometer. The disks underwent one of three surface treatments: 50 µm alumina air-particle abrasion (AAA), Zircos-E etching (ZE), or 100 µm glass bead air-particle abrasion (GBA). Post-treatment CIE Lab* measurements were obtained, and color change (ΔE₀₀, CIEDE2000) and translucency change (ΔTP₀₀) were calculated. Results: Regarding color change (ΔE₀₀), 50 µm AAA produced the greatest change, followed by ZE, while GBA caused the smallest change. Surface treatment and its interaction with material type were found to exert a significant effect, whereas material type alone was not significant. Cercon XT showed the highest numerical ΔE₀₀ value among the materials, although the difference was not statistically significant. All ΔE₀₀ values were below the clinical acceptability threshold (<1.8). No significant effects of surface treatment, material type, or their interaction were observed for translucency change (ΔTP₀₀) after surface treatment. Baseline translucency values (TP₀₀) differed significantly, with Cercon XT being the most translucent, followed by ZirCAD MT and Cercon HT, but these differences did not result in significant ΔTP₀₀ changes post treatment. Conclusions: Surface treatments and their interaction with material type significantly affected zirconia color change, with 50 µm alumina air-particle abrasion producing the most pronounced effect. Material type alone did not significantly influence ΔE₀₀, though Cercon XT showed the highest numerical value. Translucency change (ΔTP₀₀) after treatment was unaffected by surface treatment or material–treatment interaction. Full article

Background: The management of complete mandibular edentulism in frail patients with severe bone atrophy is a clinical challenge. Ultrashort implants (≤4 mm) have been proposed as a minimally invasive alternative to bone augmentation procedures; however, long-term evidence in full-arch rehabilitations remains limited. Methods: This retrospective single-center cohort study presents the 10-year follow-up of patients treated with full-arch mandibular rehabilitation under immediate loading supported by 4 mm ultrashort implants. Patients were originally treated between 2015 and 2017. The primary outcome was prosthetic success at 10 years, defined as a stable and functional prosthesis supported by four implants. Secondary outcomes included implant survival, timing of implant loss, and biological and prosthetic complications. Results: Fourteen patients were available for evaluation at the 10-year follow-up. The success of the prosthetic structure was 100%, with all patients maintaining stable and functional rehabilitation. As regards the implants, a total of 82 implants had been placed, with 14 implant losses, resulting in a cumulative implant survival rate of 82.9%. Implant losses occurred mainly in early (1 week, 4 months) and late phases (between 3 and 10 years), while no losses were observed between 1 and 3 years. Overall, 71.43% of patients experienced at least one implant loss; however, this did not compromise prosthetic function. Conclusions: In this retrospective cohort, all full-arch prostheses remained functional at 10 years, although cumulative implant survival was 82.9%. These findings suggest that rehabilitation supported by 4 mm ultrashort implants may represent a treatment option for carefully selected frail patients with severe mandibular atrophy. Prospective controlled studies are needed to confirm these findings and compare this approach with standard-length implants and bone augmentation procedures. Full article

Background/Objectives: Lower-limb amputation significantly impacts autonomy and daily functioning. Microprocessor-controlled prosthetic knees (MPKs) improve mobility, safety, and quality of life compared with non-microprocessor prosthetic knees (nMPKs). Despite general benefits, differences among MPK models remain unclear. The goal of this investigation was to evaluate functional mobility and patient-reported outcomes in active transfemoral amputees using a new MPK (PROTEOR QUATTRO) compared with existing MPKs. Methods: In this multicenter cross-over clinical trial, active transfemoral amputees were assessed using patient-specific functional scales (PSFS), standardized locomotor capacity tests (6MWT, 10mWT, HAI, SAI) and satisfaction and quality-of-life questionnaires (PEQ-A, SF-36, ESAT). Biomechanical data collection was performed during walking test, to examine gait symmetry indices. Results: The QUATTRO MPK was associated with significantly higher PSFS scores, reflecting higher self-rated ability in performing chosen daily life activities compared with patient’s current prosthesis. Standardized locomotor tests revealed comparable performance between devices. Biomechanical analyses showed similar symmetry indices for QUATTRO and other MPKs. Patient-reported outcomes showed an improvement in physical health with QUATTRO, while overall satisfaction remained similar. Conclusions: QUATTRO improved patient-perceived ability to perform meaningful daily-life activities while maintaining comparable performance on standardized locomotor tests. These results highlight the importance of patient-centered assessments in identifying functional benefits that may guide individualized prosthetic prescriptions for active transfemoral amputees. Full article

Introduction/Objectives: The mechanical reliability of prosthetic finger connectors is critical for daily prosthesis use, as these small load-bearing elements transmit forces between finger segments and are prone to localized stress concentration at hinge transitions. The objective of this study was to quantitatively evaluate the mechanical performance of prosthetic finger connectors and determine how material selection influences stress distribution and deformation behavior when connector geometry is maintained constant. Methods: A controlled comparative finite element analysis was performed using COMSOL Multiphysics 6.2 on a single prosthetic finger connector geometry manufactured from four candidate materials: titanium alloy Ti-6Al-4V (E = 110 GPa), polyetheretherketone (PEEK, E = 4.0 GPa), AvaSpire AV-621 NT (E = 3.0 GPa), and KetaSpire KT-820 FP (E = 4.1 GPa). Three representative loading scenarios were simulated using an axial grip force of 50 N and a bending moment of 0.5 N·m: (1) axial loading, (2) combined axial and forward bending, and (3) combined axial and reverse bending. Results: Across all loading conditions, peak von Mises stresses consistently localized at the hinge-transition region of the connector. Ti-6Al-4V demonstrated the lowest peak stress (approximately 2.2 MPa under combined forward bending) and the smallest maximum displacement (approximately 0.0005 mm). In contrast, the PEEK-family polymers showed greater deformation (0.0125–0.0167 mm) due to their lower elastic modulus, while maintaining comparable peak stresses of approximately 2.5–2.6 MPa. The stress profiles along the connector arc length were nearly identical among all materials, indicating that connector geometry primarily governs stress localization, whereas material stiffness mainly determines deformation magnitude. Conclusions: This study demonstrates that material selection strongly affects prosthetic finger connector compliance, while stress concentration behavior is mainly controlled by geometry. The obtained quantitative comparison provides design-oriented guidance for selecting between Ti-6Al-4V and PEEK-based polymers for the development of lightweight and mechanically reliable prosthetic finger connectors. Full article

Objective: The aim of this study was to assess the predictability of a digital workflow for manufacturing provisional maxillary removable dentures and immediately loaded implant-supported mandibular prostheses. Materials and Methods: Eighteen completely edentulous patients were enrolled. Complete dentures, when present, were adapted; when they were absent, records with a denture base and wax rim were fabricated. The adjusted prostheses were scanned, generating STL files; photographs with the prostheses in occlusion were used to generate a virtual patient; and lateral cephalometric radiographs were obtained. Virtual tooth arrangement was performed, and, after approval, a maxillary denture and a mandibular prosthesis in multifunctional guide format were printed and evaluated intraorally. Four implants (Nuvo, Brazil) were installed using a guide (which was also used as a tray and for registration). In the laboratory, the guide was converted into an interim fixed prosthesis. After installation, the prostheses were evaluated independently by three examiners. A new lateral cephalometric radiograph was obtained in occlusion. Descriptive analysis of the data obtained from the professional evaluation was carried out, and the Shapiro–Wilk test was used to test the adherence of the data to a normal distribution for quantitative variables. Results: The professional satisfaction rate for the clinical evaluation and installation of the prostheses was >9. The different factors were always favorably appraised, with strong agreement between examiners. The cephalometric analysis of OVD showed reproducibility with respect to the initial clinical determination. Conclusions: Although the study included a small number of patients, based on the results obtained, it seems reasonable to conclude that this digital workflow exhibits predictability for rehabilitation with 3D-printed provisional maxillary dentures and immediately loaded implant-supported provisional prostheses. Full article