Prosthesis, Volume 8, Issue 1 (January 2026) – 12 articles

Objectives: This study investigated the effects of three over-the-counter (OTC) whitening products, whitening pen (WP, Dazzling White Instant Whitening Pen, Dazzling White, Grand Rapids, MI, USA), whitening mouthwash (MW, Colgate Optic White, Colgate-Palmolive, New York, NY, USA), and whitening toothpaste (TP, Crest 3D White, Procter & Gamble, Cincinnati, OH, USA), on the microhardness, gloss retention, and surface roughness of a nanofilled resin composite (Filtek Z350 XT Universal Restorative, 3M ESPE). Methods: Composite resin specimens were prepared and subjected to treatment with WP, MW, or TP. Microhardness, gloss retention, and surface roughness were measured before and after treatment. Data were subjected to statistical analysis, with normality assessed by Shapiro–Wilk testing. Parametric data were summarized as mean ± SD, and differences were evaluated using paired t-tests and one-way ANOVA with a significance level of p ≤ 0. 05. Results: All whitening products significantly altered the tested surface properties. Microhardness decreased in all groups (MD [95% CI]: 2.28 [1.84–2.71] for WP, 5.05 [4.22–5.88] for MW, and 3.09 [2.35–3.83] for TP; p < 0.001), with the greatest reduction observed in the MW group. Gloss retention also declined significantly (MD [95% CI]: 9.52 [6.28–12.76] for WP, 17.97 [14.92–21.01] for MW, and 18.92 [15.64–22.21] for TP; p < 0.001), with TP and MW showing greater loss compared to WP. Surface roughness increased significantly within each group (MD [95% CI]: −0.07 [–0.10 to −0.04] for WP, −0.23 [–0.30 to −0.16] for MW, and −0.25 [–0.38 to −0.13] for TP; p < 0.001), although no significant differences were found among groups in post-treatment values. Conclusions: OTC whitening products adversely affected the optical and mechanical properties of Z350 XT universal composite resin. Whitening MW caused the most pronounced microhardness reduction, while MW and TP induced greater gloss loss than WP. Clinicians should consider the potential impact of whitening products on resin composite restorations when advising patients on their use. Full article

Background/Objectives: The use of zirconia implants is gaining traction as a potential alternative to titanium. Although having excellent properties, the zirconia surface has limited osteogenic potential. The purpose of this study was to produce, for the first time, mechanically stable, thick micron-scale hydroxyapatite coatings on zirconia implant material using radiofrequency (RF) magnetron sputtering. Methods: Zirconia samples were coated with HA using an RF magnetron sputtering device at a temperature of 125 °C for 20 h with 155 W of power. The procedure included rotating the substrate at a speed of 10 rpm while an argon gas flow was maintained continuously. Field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) analysis, atomic force microscopy, and Vickers hardness measurements were used to evaluate the coat’s characteristics. Results: A smooth hydroxyapatite coating layer that was consistent and free of cracks was observed in all FESEM pictures. The EDX study revealed that the substrate surface contains HA particles, and the ratio of calcium (Ca) to phosphorus (P) was 16.58 to 11.31, which is very close to the ratio in original HA. FESEM cross-section pictures showed good adhesion between the coating and substrate without any gaps, and the coating thickness was 5 µm on average. A statistically significant difference was found in the roughness analysis between the samples of uncoated Zr and HA-coated Zr (p-value < 0.05). Conclusions: Zirconia implant material can be coated with a uniform layer of HA, displaying good adhesion and a thickness of a few micrometers when using magnetron sputtering for an extended period of time. Full article

Background/Objectives: Oral function impairment negatively impacts nutrition, health, and quality of life in older adults. While retaining ≥20 natural teeth is often recommended for maintaining oral function, its validity is uncertain, particularly for those who adapt to tooth loss with dentures. This study aimed to determine the minimum number of remaining functional teeth necessary to prevent oral hypofunction in older adults, focusing on two diagnostic criteria: decreased masticatory function and reduced occlusal force. Methods: A total of 154 participants (≥60 years) were included. Oral examination assessed the number of remaining functional teeth. To assess masticatory function, masticatory performance was objectively measured using a visual scoring method of gummy jelly, and occlusal force was quantified with pressure-sensitive film. Pearson’s correlation analyzed relationships among variables, while receiver operating characteristic (ROC) analysis identified optimal tooth number cut-offs for detecting decreased masticatory function (score ≤ 2) and reduced occlusal force (<500 N). Results: Significant positive correlations were found between the number of remaining functional teeth and both masticatory performance (r = 0.591, p < 0.001) and occlusal force (r = 0.453, p < 0.001). ROC indicated that 17 teeth was the optimal threshold for identifying both decreased masticatory performance and reduced occlusal force, with sensitivities of 0.79 and 0.72 and specificities of 0.93 and 0.88, respectively. Conclusions: Retention of 17 or more remaining functional teeth may be sufficient to maintain adequate masticatory performance and occlusal force. These findings serves as a preliminary guide for treatment planning and targeted interventions focused on preserving tooth retention and improving oral function in aging populations. Full article

Background/Objectives: An individual with a hand disability, whether caused by an accident, disease, or congenital condition, may have significant problems with their daily activities, self-perception, and ability to work. Prosthetic hands can be used to restore essential hand functions, and features such as adaptive grasps can enhance their usability. Due to noise in the sEMG signal and hardware limitations in the system, reliable myoelectric control remains a challenge for low-cost prosthetics. ESP32 microcontrollers are used in this study to develop an SVM-based sEMG classifier that addresses these issues and improves responsiveness and accuracy. A 3D-printed mechanical structure supports the prosthesis, reducing production costs and making it more accessible. Methods: The prosthetic hand is developed using an ESP32 as the microcontroller, a Myoware Muscle Sensor to detect muscle activity, and an ESP32-based control system that integrates sEMG acquisition, SVM classification, and finger actuation with FSR feedback. A surface electromyography (sEMG) method is paired with a Support Vector Machine (SVM) algorithm to help classify signals from the sensor to improve the user’s experience and finger adaptability. Results: The SVM classifier achieved 89.10% accuracy, an F1-score of 0.89, and an AUC of 0.92, with real-time testing demonstrating that the ESP32 could reliably distinguish flexion and extension signals and actuate the servo, accordingly, producing movements consistent with the kinematic simulations. Complementing this control performance, the prosthetic hand was constructed using a coupled 4 bar linkage mechanism fabricated in PLA+, selected for its superior factor of safety compared to the other tested materials, ensuring sufficient structural reliability during operation. Conclusions: The results demonstrate that SVM-based sEMG classification can be effectively implemented on low-power microcontrollers for intuitive, low-cost prosthetic control. Further work is needed to expand beyond two-class detection and increase robustness against muscle fatigue and sensor placement variability. Full article

Background: Resin infiltration has emerged as a micro-invasive strategy for managing enamel porosities, offering both therapeutic and aesthetic benefits. ICON^® (DMG, Hamburg, Germany) is the most widely used system; however, evidence on its penetration behavior in sound enamel remains limited. Objectives: This in vitro study aimed to evaluate the penetration depth and morphological pattern of ICON resin infiltration in sound human enamel, using quantitative morphometric analysis and scanning electron microscopy (SEM). Methods: Fourteen freshly extracted, caries-free anterior teeth were sectioned longitudinally. ICON^® resin infiltrate was applied to the buccal enamel surfaces according to the manufacturer’s protocol, while the lingual/palatal surfaces served as internal controls. Penetration depth was measured quantitatively on both mesial (surface A) and distal (surface B) halves, and SEM was used to assess resin–enamel interface morphology. Statistical analysis included the Shapiro–Wilk test, paired t-test, Pearson correlation, and percentage difference calculation. Results: The mean difference in penetration depth between surfaces A and B was −21.29 µm (p = 0.525), indicating no statistically significant variation. A strong positive correlation was observed between surfaces (r = 0.783, p = 0.001). The mean percentage difference was −3.57% (SD = 18.61%), suggesting minimal directional bias. SEM images confirmed continuous and homogeneous resin infiltration within enamel prisms. Post-hoc power analysis indicated 15.2% power, reflecting the impact of the limited sample size typical for SEM-based exploratory studies. Conclusions: Within the limitations of this in vitro investigation, ICON resin infiltration demonstrated uniform and consistent penetration in sound enamel, supported by both quantitative and SEM analyses. These findings validate its potential as a reliable preventive and micro-invasive biomaterial in dental practice, particularly for protecting enamel surfaces prior to orthodontic bracket bonding. Further clinical research with larger cohorts is recommended to confirm its long-term stability and prophylactic performance. Full article

Upper limb deficiencies can limit the range of tasks children can perform. Current prosthetics provide overall good performance to increase the activities that users can complete, but challenges remain. Body- or electrically powered prostheses struggle to restore the full range of motion needed for specific tasks. Currently, these systems do not allow for controlled hand closure or opening across all possible postures. A breathing-powered prototype named Airbender, which extracts energy from a breathing input by means of a Tesla turbine, provides the possibility of operation in any position. This paper introduces a novel design for a multi-finger actuated breathing-powered upper limb prosthetic concept and analyses its performance through a series of lab-based experiments. Results show that such a design could provide a fully controllable system. The final assembled design is capable of achieving full actuation under a flow rate of 340 Ls/min. The results obtained demonstrate that a functional multi-finger actuated breathing-powered upper limb prosthesis could be feasible and opens a path for future research in the field, with the ultimate goal of reducing the minimum flow rate required and actuation time to further improve its functionality. Full article

Background: Rehabilitation of head and neck cancer patients with acquired intraoral defects is challenging and requires multidisciplinary collaboration. This case report describes an integrated surgical and prosthetic approach in which palatal obturator rehabilitation is used to restore palatal integrity, speech, swallowing, aesthetics, and overall quality of life after maxillectomy. The objective is to show how careful surgical planning to optimize prosthetic prognosis, combined with a precisely designed obturator prosthesis, can achieve satisfactory functional rehabilitation. Methods: A man in his 50s with sinonasal carcinoma underwent partial left maxillectomy followed by radiotherapy and chemotherapy. The defect was classified as Aramany class I and Brown class 2b, and the surgical resection was planned to preserve structures favorable to prosthetic support. Prosthetic management included fabrication of a removable partial denture incorporating a hollow-bulb obturator. Results: During trial and delivery, the patient demonstrated improved speech and swallowing, enhanced denture stability, and favorable aesthetics. The patient reported satisfaction with functional and cosmetic outcomes and was provided with instructions for use and cleaning, with a plan for regular follow-up. Conclusions: Palatal obturator prostheses remain a gold standard for unilateral maxillectomy rehabilitation when adequate retention is achievable. Surgical-prosthetic collaboration permits restoring palatal contours, and dentition can normalize speech and swallowing, and substantially improve the quality of life. Full article

Background: Various socket designs exist, linking the residual limb together with the prosthetic components to restore the ability to walk; however, lack of socket comfort is a frequent complaint. Objective: To evaluate the impact of socket design on end-user comfort and mobility. Methods: A randomized crossover trial was set to compare comfort and mobility of above-knee amputees (AKAs) wearing an ischial containment (IC) or subischial (I-SUB) socket. Patients actively wearing IC sockets were recruited from 10 rehabilitation centers across the country. They were then fitted for an I-SUB socket by Certified Prosthetists (CPs) as an alternate socket. Participants were randomly assigned to start with one or the other socket. After a minimum of 2 weeks, each participant evaluated the Socket Comfort Score (SCS) (primary outcome) in various situations, performed the 2-min walk test, and answered the PLUS-M questionnaire (secondary outcomes). Results: A total of 25 participants were included, of whom 23 completed the study with full (n = 21) or partial data (n = 2). SCS were improved with I-SUB compared with IC in all situations, with significant differences in general, when sitting on a rigid chair, sitting in a car, and standing. The differences in self-reported mobility and walking distance at the 2-min walk test were not significant. At the end of the study, more than 80% of the participants chose to keep the I-SUB socket for their daily use. Conclusions: For the first time, this study supports that the subischial suction socket improves comfort in daily life without negatively impacting user mobility in a group of individuals with AKA. Full article

Background: Postoperative infections remain a major complication in spinal surgeries involving intersomatic screws, often compromising osseointegration and long-term implant stability. Questions/Purposes: This study evaluated a nanotextured titanium oxide surface with nanopillar-like morphology designed to reduce bacterial colonization while preserving mechanical integrity and promoting bone integration. Methods: Ti₆Al₄V screws were studied in three batches: control, passivated with HCl and acid mixture treatment to obtain nanotopographies on the surfaces. To create the nanotopographies, the screws were treated with a 1:1 (v/v) sulfuric acid–hydrogen peroxide solution for 2 h. Surface morphology, roughness, wettability, and surface energy were analyzed by SEM, confocal microscopy, and contact angle measurements. Corrosion and ion release were assessed electrochemically and by ICP-MS, respectively. Mechanical behavior, cytocompatibility, mineralization, and antibacterial efficacy were evaluated in vitro. Osseointegration was analyzed in rabbit tibiae after 21 days by histology and bone–implant contact (BIC). Results: The treatment produced uniform nanopillars (Ra = 0.12 µm) with increased hydrophilicity (49° vs. 102° control) and higher surface energy. Mechanical properties and fatigue resistance (~600 N, 10 million cycles) were unaffected. Corrosion currents and Ti ion release remained low. Nanopillar surfaces enhanced osteoblast adhesion and mineralization and reduced bacterial viability by >60% for most strains. In vivo, Bone Index Contact (BIC) was higher for nanopillars (52.0%) than for HCl-treated (43.8%) and control (40.1%) screws, showing a positive osseointegration trend (p > 0.005). Conclusions: The proposed acid-etching process generates a stable, scalable nanotopography with promising antibacterial and osteogenic potential while maintaining the alloy’s mechanical and chemical integrity. Clinical relevance: This simple, scalable, and drug-free surface modification offers a promising approach to reduce postoperative infections and promote bone integration in spinal implants. Full article

Background/Objectives: This in vitro study examined the potential enhancement in resistance to accelerated aging in room-temperature vulcanized (RTV) maxillofacial silicone, intrinsically pigmented in two skin tones, through the use of zirconium oxide (ZrO₂) nanoparticles. Methods: A total of 128 disc-shaped specimens were created in rose silk and soft brown shades, each containing zirconium oxide concentrations of 0%, 1%, 2%, and 3% by weight. Color variation (ΔE*) was assessed initially and following 252, 750, and 1252 h of artificial aging, tested with a colorimeter. Surface roughness characteristics (R_a, R_q, R_t) were evaluated before and after 1252 h using atomic force microscopy (AFM). Structural, vibrational, and morphological characteristics were analyzed through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM). Results: Non-parametric tests (Friedman, Kruskal–Wallis, and Bonferroni-adjusted paired testing; p < 0.05) indicated that accelerated aging significantly increased ΔE* in all specimens. The addition of ZrO₂ reduced these changes; however, the optimal concentration differed by pigment: 1% for rose silk and 3% for soft brown. The effect on surface roughness depended on pigment type. Higher nanoparticle concentrations generally improved post-aging smoothness in soft brown samples, whereas rose silk showed a more variable response. XRD and FTIR analyses confirmed successful nanoparticle incorporation without altering the fundamental silicone structure, while FESEM demonstrated improved filler–matrix interaction in modified groups. Conclusions: Adjusting ZrO₂ concentration according to pigment type can improve the future color retention and surface characteristics of maxillofacial silicone. Full article

Background/Objectives: The rapid evolution of digital technologies has significantly transformed prosthodontic workflows, improving clinical precision, communication, and patient satisfaction. However, the extent to which dental professionals perceive, integrate, and evaluate these technologies remains insufficiently standardized. This study aimed to develop and validate a questionnaire for assessing perceptions, attitudes, perceived advantages, barriers, and future intentions regarding the use of digital technologies in prosthodontic practice. Methods: A cross-sectional survey was conducted among 420 dental professionals (305 dentists and 115 dental technicians) from Northeastern Romania. The 27-item questionnaire, structured on five theoretical dimensions, was distributed online via the Survio platform. Internal consistency was assessed using Cronbach’s Alpha, and construct validity was analyzed through Exploratory Factor Analysis (Principal Component Analysis with Varimax rotation). Conclusions: Cronbach’s Alpha coefficients ranged from 0.700 to 0.799 across the five dimensions, indicating acceptable to very good internal reliability. The Kaiser–Meyer–Olkin value (0.646) and Bartlett’s Test of Sphericity (p < 0.001) confirmed data suitability for factor analysis. The validated questionnaire represents a reliable and conceptually coherent tool for evaluating professional perspectives on digitalization in prosthodontics. Its application can inform educational strategies, guide institutional investments, and support a balanced transition toward integrated digital workflows in clinical and laboratory settings. Full article

Background/Objectives: Amputation often leads to decreased body image satisfaction and self-acceptance, affecting mental health and social integration. The Amputee Body Image Scale (ABIS) is a validated tool designed to assess satisfaction and measure body image acceptance. The scale has been translated into many languages to improve rehabilitation services for individuals with amputation worldwide; however, a validated Arabic version of this scale does not currently exist. The study aims to cross-culturally adapt and validate the ABIS for Arabic-speaking individuals with lower-limb amputation. Methods: A cross-cultural adaptation was performed according to the International Test Commission (ITC) guidelines. The adapted Arabic version of the scale was completed by 100 Jordanian individuals with lower-limb amputations. Their responses were then statistically analyzed using factor analysis to assess content and construct validity and Cronbach’s α to assess internal consistency (reliability). Results: The Arabic version of the ABIS demonstrated strong construct validity (KMO = 0.898; Bartlett’s test p < 0.001) and high internal consistency (Cronbach’s alpha = 0.92), while factor analysis suggested the multidimensionality of the scale after cross-cultural adaptation. Conclusions: The findings suggest the preliminary validity and reliability of the Arabic version of the ABIS, supporting its potential use in rehabilitation centres to assess body image satisfaction among Arabic-speaking individuals with amputation. Nevertheless, further improvements are warranted to adapt the scale to Arabic culture. Full article