Search Results (152)

The incorporation of antimicrobial additives into 3D-printed denture base resins is a promising strategy for reducing denture stomatitis, but the mechanical consequences and temporal stability of such modifications remain poorly characterized. This in vitro pilot study evaluated the effects of incorporating 4% (w/w) K18—a quaternary ammonium methacryloxy silane dissolved in isobornyl acrylate (IBOA)—into three commercially available photopolymer resins printed across four platforms representing stereolithography, digital light processing, and liquid crystal display technologies. Flexural strength, flexural modulus, and flexure at break were measured at three time points: without K18, immediately after mixing, and one-week post-mixing. K18-IBOA incorporation produced significant reductions in all mechanical parameters across most resin–printer combinations. The magnitude and direction of changes were strongly dependent on printer–resin combination interactions, precluding generalization across systems. At one week, visible clumping consistent with phase separation was observed in all formulations, and one resin–printer combination exhibited catastrophic structural failure upon removal from the build platform. These findings suggest that 4% w/w K18-IBOA additions are unlikely to yield clinically acceptable denture bases without further formulation optimization, underscoring the importance of temporal stability assessment in the development of antimicrobial-modified photopolymer resins. Full article

Acrylic resin is widely used in the fabrication of complete dentures, interacting significantly with the intraoral environment. However, complete dentures face challenges such as stability issues and biofilm accumulation. Glaze application is a common method to reduce surface porosity and microbial adhesion, but it also decreases surface wettability, potentially impairing salivary film formation essential for peripheral sealing. This study aimed to incorporate titanium dioxide and zinc oxide nanoparticles into the glaze applied to thermally activated acrylic resin (TAAR) via spray coating to enhance surface wettability and antifungal activity. Four groups were tested: G (TAAR + commercial glaze − control); AlG (TAAR + commercial glaze + aluminum oxide − roughness control); TiG (TAAR + commercial glaze + titanium dioxide); and ZnG (TAAR + commercial glaze + zinc oxide). Evaluations included flexural strength, color and translucency, surface analysis and antibiofilm activity against Candida albicans. Data were analyzed using one-way ANOVA. No statistically significant differences in mechanical strength (MPa) were observed (G: 108.54 ± 8.36; AlG: 113.60 ± 11.95; ZnG: 111.98 ± 9.27; TiG: 113.66 ± 10.41). Surface roughness significantly increased, and contact angle decreased, indicating improved wettability. Regardless of the antifungal activity no improvement was detected (G: 6.71 ± 0.10; AlG: 6.82 ± 0.08; ZnG: 6.72 ± 0.20; TiG: 6.66 ± 0.18). In conclusion, the incorporation of nanoparticles into the glaze improves the wettability of acrylic resin surfaces, potentially enhancing peripheral sealing and denture retention, which is beneficial for patients with reduced alveolar ridge height. Full article

Background/Objectives: Delivering consistent preclinical instruction for implant attachment procedures can be challenging in large dental cohorts. This report describes the development and implementation of institutionally produced training tools designed to support Locator housing pick-up exercises for second-year predoctoral dental students. Methods: Modified typodont-based simulation tools were integrated into the preclinical curriculum. Clear dentures and gypsum models were fabricated to allow visualization of seating relationships and identification of common interferences. Complete seating of the denture was verified using inspection windows, flange evaluation, and polyvinylsiloxane disclosing materials before housings were incorporated with autopolymerizing acrylic resin. After each session, components were collected, inspected, and prepared for reuse in subsequent cycles. Learner perceptions were obtained through an anonymous voluntary survey. Results: The configuration enabled visualization of seating conditions and identification of misalignment during the exercise. Removal of anterior teeth reduced material use and emphasized posterior stabilization during the pick-up procedure. Of 83 learners, 28 completed the survey (34% response rate), with responses tending toward agreement across items (mean range: 4.5–4.9/5), indicating favorable learner perceptions of the exercise and its organization within the scheduled laboratory period. Across three academic cycles, six dentures required replacement, whereas all gypsum models remained serviceable and no additional fabrication was necessary. Conclusions: This structured simulation approach provided an alternative method for delivering Locator housing pick-up training in a high-volume preclinical environment. The model allowed repeated implementation of the exercise across academic cycles. Full article

Aim: This literature review presents the biological evaluation of light-curing 3D printing materials containing methacrylic and acrylic resin in dentistry. The sample was 42 articles published between 2008 and 2025, available on PubMed, Scopus, Cochrane, and Google Scholar. The articles were analyzed following the assessment requirements of ISO 10993-2018 (Endpoint) regarding the biological evaluation of each Medical Device. The first selection criterion of the articles was based on the PRISMA schema, concerned with the application of these materials in various fields of dentistry used in 3D printing (e.g., material for crowns and bridges, night, and surgical guide, orthodontic, and denture base). The second criterion included the composition of materials (e.g., catalysts, methacrylic resins, and stabilizers) and the post-curing process. Results: The topics discussed in the literature included: (a) estrogenic interactions, sensitization, and the zebra fish model to determine acute toxicity; (b) the main post-processes affecting biocompatibility, i.e., alcohol washing and polymerization in light ovens; and (c) the modification of 3D resins using various types of nanomaterials. Conclusions: 3D resins can be used safely in dentistry to make various types of restorations, provided that the polymerization, washing with alcohol and post-polymerization in a light oven follow the manufacturer’s specifications. Full article

Background/Objectives: Denture stomatitis is closely associated with Candida albicans colonization of denture-base surfaces. This in vitro study compared early adhesion (1 h) and initial biofilm formation (24 h) of C. albicans across five denture-base-related material groups using adhered cell counts and adhered/inoculum proportions. Methods: A 5 × 2 factorial design (five material groups; 1 and 24 h) evaluated a comparator pattern resin, heat-polymerized acrylic resin, autopolymerizing acrylic resin, milled CAD/CAM PMMA, and microwave-polymerized acrylic resin. All specimens underwent standardized finishing and mechanical polishing before microbiological testing. Data were log10-transformed and analyzed by two-way ANOVA (material group, time) with Tukey’s post hoc test. An external SEM-based qualitative laboratory report was used as complementary documentation of C. albicans presence after 1 h and 24 h; representative micrographs and quantitative SEM image outputs were unavailable. Results: Material group, time, and their interaction significantly affected adhered C. albicans counts (p < 0.05). At 1 h, the comparator pattern resin showed the highest adhesion, whereas at 24 h, milled CAD/CAM PMMA showed the highest adhered load. For the adhered/inoculum fraction, both material group and time were significant; at 24 h, the heat-polymerized acrylic resin showed the lowest adhered fraction. Conclusions: Under the standardized finishing and mechanical polishing conditions of this in vitro model, the tested material groups showed different C. albicans adhesion/biofilm patterns over time; clinical extrapolation should be made with caution. Full article

This study evaluated the physical and mechanical properties of acrylic resins used for interim fixed prostheses, with and without metal reinforcement, before and after aging. A total of 138 samples were divided into three groups: VIPI + Wire (control), VIPI, and Diamond D. Samples were assessed for microhardness, porosity, roughness, and flexural strength. Aging was simulated using 500 thermocycling cycles at 5 and 55 ± 1 °C. Data were analyzed using ANOVA and Tukey’s test. Group Diamond D did not fracture during flexural testing, but it exhibited significantly lower microhardness at both baseline and after aging. Before aging, Group Diamond D had higher roughness than Group VIPI, which exhibited greater porosity. Aging increased the microhardness of Group VIPI and the roughness of Group Diamond D. The percentage of porosity decreased significantly for Groups VIPI + Wire and VIPI, and pore size was reduced in all groups. Based on the results obtained from Diamond D material, this resin does not meet the required properties for the proposed indication for temporary fixed prostheses, whereas VIPI with reinforcement showed superior properties and greater stability after aging. Full article

Introduction: Acrylic materials have been a staple in dental prosthetics for decades. Developments in manufacturing technology, including additive techniques, have led to the introduction of new types of acrylics, whose mechanical properties require detailed evaluation and comparison with conventional materials. Aim of the study: The aim of the study was to comparatively evaluate selected mechanical properties, such as hardness, impact strength, density, flexural strength, and tensile strength, of three types of acrylic materials used in prosthetics: 3D-printed acrylic, heat-cured acrylic, and cold-cured acrylic, in vitro. Materials and Methods: Three materials were used in the study: 3D-printed acrylic (NextDent Denture 3D+), heat-cured acrylic (made using the cupping method (Villacryl H Plus)), and cold-cured acrylic (made using the pouring method (Villacryl SP)). Ten samples (n = 30) were prepared from each material. Flexural strength, tensile strength, Young’s modulus, density, Vickers hardness, and impact strength were tested. Results: The tested materials demonstrated significant differences in mechanical properties. The highest values for impact strength, flexural strength, tensile strength, and density were obtained for 3D-printed acrylic. Hot-cured acrylic achieved the highest hardness values. Cold-cured acrylic, on the other hand, achieved the lowest results, except for the impact strength test, where it achieved intermediate results. Conclusions: The mechanical properties of dental acrylics are significantly dependent on their manufacturing technology. Hot-cured acrylic exhibits the highest hardness, while 3D-printed acrylic is characterized by favorable impact strength, flexural strength, and tensile strength, which may have significant clinical significance in terms of the resistance of dentures to mechanical damage. The study results could provide a basis for introducing this material into clinical practice. Full article

Background/Objectives: This technical report introduces an innovative hybrid digital workflow that integrates diagnostic plaster-cast scanning with intraoral scanning to produce an accurate 3D-printed model for fabricating distal-extension removable dental prostheses (RDPs). Methods: The technique aims to overcome the challenges of reproducing the mobile mucosa in free-end saddles, a critical factor for denture base accuracy and stability. The workflow began with conventional clinical procedures, including clinical examination, impression-making, and cast surveying. After performing the required mouth preparations according to the prosthetic design, the diagnostic cast was digitized and selectively modified to allow intraoral rescanning. The prepared teeth were then scanned intraorally and merged with the digitalized cast, producing a refined virtual model for CAD-based metal framework design. The framework was digitally designed, 3D-printed to verify adaptation, and cast in cobalt–chromium. Standard RDP fabrication steps were followed, including intraoral framework try-in, fabrication of acrylic bases, occlusal registration, tooth arrangement, and functional and esthetic try-in. The final prosthesis was installed and adjusted without the need for an additional impression. Results: This hybrid workflow enabled a highly accurate reproduction of the distal extension region, outperforming models derived solely from direct intraoral scanning. By digitally capturing the physiological morphology of the mobile mucosa, the method eliminates the need for the traditional altered-cast technique, reducing clinical time, technical sensitivity, and material costs. Conclusions: The proposed approach enhances denture base accuracy, improves adaptation, and promotes more uniform occlusal load distribution in free-end RDPs. This streamlined and reproducible digital protocol offers a clinically relevant advancement, with potential to improve prosthesis stability and long-term outcomes. Full article

Saliva is essential for maintaining oral health, and conditions like hyposalivation increase the risk of diseases. To address this, artificial saliva (AS) formulations incorporated with antimicrobials have been proposed. This study aimed to evaluate the antimicrobial activity and determine the minimum inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of AS formulations containing nystatin (Nys), chlorhexidine diacetate 98% (Chx), and silver nanoparticles (AgNp) against Candida albicans biofilm. The fungistatic and fungicidal properties of six groups (AS; AS + AgNp 2 mM; AS + AgNp 4 mM; AS + AgNp 6 mM; AS + Nys; AS + Chx) were assessed using the XTT colorimetric assay. Additionally, 35 denture base heat-polymerized acrylic resin specimens were prepared and treated with the antimicrobials, serving as substrates for C. albicans biofilm development over 3, 6, and 12 h. Biofilm growth was quantified by CFU/mL counting. All analyses were performed with a significance level of p < 0.05. Results demonstrated fungal load inhibition and a reduction in metabolic activity across all experimental groups (p < 0.05). Notably, AS + Nys, AS + Chx, and AS + AgNp 6 mM exhibited similar and significant inhibitory effects against C. albicans biofilm. Full article

Acrylic resins are commonly used for denture bases due to ease of molding but are prone to water absorption and microbial contamination. This study aimed to evaluate the effects of ozonated water immersion (OZ), ultrasonic cleaning (US), and ultraviolet (UV) irradiation on the removal of Candida albicans from acrylic resins produced by heat curing and additive manufacturing. The resin specimens were then subjected to treatment with OZ, US, UV irradiation, and commercial denture cleansers. Following treatment, the number of viable C. albicans cells was quantified and statistically analyzed (α = 0.05), morphology was observed under a scanning electron microscope (SEM) and fluorescence imaging. OZ, US, and UV irradiation significantly reduced the viable C. albicans count. Notably, the combination of the three treatments achieved a reduction exceeding 99.9% of viable cells. Although SEM revealed that C. albicans remained on the specimens, fluorescence imaging demonstrated a progressive decrease in viable cells and an increase in dead cells with each treatment, with the greatest effect observed when the three treatments were combined. The difference of removal behaviors of C. albicans among fabrication methods was not observed, comparable to denture cleaners. The combined application of all three treatments was the most effective strategy for microbial removal. Full article

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/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

Beyond mechanical performance and aesthetics, the susceptibility of 3D-printed resins to microbial colonization and biofilm formation represent an important factor influencing dentures’ longevity. Therefore, this study evaluated Candida albicans colonization and mature biofilm formation on three different 3D-printed denture base resins (Bio Denture—BD; Denture Base Cosmos—CD; Smart Print Bio Denture—SP) and compared them to heat-curing resin (HC). Before the microbiological evaluation, the surface roughness (Sa) was assessed. Biofilm viability was determined through colony-forming units per milliliter (CFU/mL) and biofilm morphology was qualitatively examined using a scanning electron microscope (SEM). The composition of the extracellular polymeric substance (EPS) was investigated by measuring the amounts of carbohydrates (µg/mL), proteins (ng/mL), and extracellular DNA (eDNA) (fluorescence unit). One-way ANOVA was performed for eDNA and Sa and Kruskal–Wallis for the other properties (α = 0.05). Higher surface roughness mean values (standard deviation) (p < 0.05) were observed in CD [0.111 (0.013)] compared to HC [0.084 (0.018) and BD [0.078 (0.015)]. For wettability, BD [63.2 (5.2)] and SP [65.2 (3.1)] resins showed a greater wettability (p < 0.05) than HC resin [73.0 (3.5)], while SP showed lower (p < 0.01) protein levels (425 ng/mL) compared to HC (568.6 ng/mL) and BD (554.8 ng/mL) in the EPS. Despite these differences, the 3D-printed denture base resins exhibited microbial load (CFU/mL), EPS composition (carbohydrates and eDNA), and morphological features of C. albicans biofilm comparable to those of conventional heat-cured PMMA. These findings suggest that, despite resin-specific variations, 3D-printed denture base materials exhibit a similar susceptibility to C. albicans colonization and biofilm formation as conventional denture bases, thereby directing future research towards developing new 3D-printed resins with enhanced antimicrobial properties to improve clinical outcomes. Full article

Acrylic resin is widely used in removable dental prostheses due to its biocompatibility, low cost, and ease of handling; however, it presents mechanical limitations and a high susceptibility to microbial colonization, particularly by Candida albicans. The incorporation of nanoparticles into polymethyl methacrylate (PMMA) has been investigated as a strategy to mitigate these drawbacks. This scoping review evaluated the impacts of incorporating chitosan (CTS) nanoparticles into PMMA on antimicrobial activity and mechanical properties. A comprehensive search of the PubMed, Scopus, Web of Science, and BVS databases resulted in the retrieval of 1912 records. After removing 557 duplicates and applying the eligibility criteria, 9 in vitro studies were included. Despite methodological heterogeneity, most studies reported enhanced antifungal activity against C. albicans and improvements in mechanical properties, such as microhardness and overall strength, when CTS was incorporated. Thus, CTS appears to be a promising additive for denture base resins, with the potential to reduce denture-associated infections and increase the longevity of prostheses. Nevertheless, standardized methodologies and well-designed in vivo and clinical investigations remain essential to determine optimal concentrations, incorporation techniques, and long-term clinical performance before implementation. A scoping review design was selected due to the exploratory nature of the study and the heterogeneity of available evidence, which precludes direct comparisons and quantitative synthesis. Full article

The effects of free radicals and chronic oxidative stress are the cause of many diseases, including those of the oral cavity, among which the most important are inflammatory processes and cancer. For this reason, an important element of the body’s defense is maintaining proper antioxidant activity. Study aim: To assess oxidative stress parameters in the saliva of patients using removable prostheses after head and neck cancer surgery. Material and methods: 44 oncological patients operated on for head and neck cancer and 20 healthy edentulous volunteers as a control group. Removable acrylic dentures were prepared for both groups. The material for oxidative stress analysis was saliva: non-stimulated saliva (NWS) and stimulated saliva (SW) after 3 months of prosthetic treatment. Results: Changes in the level of oxidative stress parameters were observed in the study group after 3 months of prosthetic treatment. Specifically, we observed a higher level of deoxyribonucleic acid (DNA)/ribonucleic acid (RNA) damage in oncology patients compared to controls. The levels of protein oxidation products—protein carbonyls, lipid peroxidation products, malondialdehyde (MDA), and nitrotyrosine—were slightly higher in the study group in all measurements. Conclusion: Based on this study, it was found that removable prostheses have a minor impact on the level of enzymatic and non-enzymatic oxidative stress parameters. This research suggests an adaptation to prosthetic restorations that results in almost restored redox balance. Full article