This study aimed to compare surface properties, degree of conversion (DC), short-term eluate levels, and biocompatibility between high-filler three-dimensional (3D) printed dental resins, low-filler 3D printed dental resins, and milled ceramic materials. Two commercial high-filler 3D printed resins (containing zirconia and silica), one commercial low-filler 3D printed resin, one hybrid milled ceramic, and one zirconia milled ceramic were tested. The surface properties evaluated were degree of conversion (DC) (n = 10), contact angle and surface free energy (SFE) (n = 10), surface roughness using contact-type profiler (n = 10) and Atomic Force Microscopy (AFM, n = 1) and surface morphology using Scanning Electronic Microscopy (SEM, n = 1). Biocompatibility was assessed by measuring the viability (n = 10), proliferation (n = 3), and migration (n = 6) of human gingival fibroblasts after exposure to material eluates. Eluates were analyzed subjectively using liquid chromatography–tandem mass spectrometry (n = 1). Data were analyzed statistically using one-way ANOVA with Tukey’s HSD test (α = 0.05). High-filler resins showed significantly higher DC than the low-filler resin (p < 0.05). Postcuring increased DC in the low-filler resin but not in high-filler resins. High-filler resins and the hybrid ceramic exhibited higher surface energy and lower contact angles than zirconia and the low-filler resin, while surface roughness was highest in the hybrid ceramic and lowest in the low-filler resin (p < 0.05). Eluates had no effect on viability or proliferation but significantly reduced fibroblast migration for the high-filler resins and hybrid ceramic (p < 0.05). High-filler 3D printed resins demonstrated higher DC and surface energy but released more residual monomers than the low-filler resin and ceramics. While eluates did not impair cell viability or proliferation, they reduced fibroblast migration, suggesting possible implications for soft-tissue healing. High-filler 3D printed resins exhibit acceptable biocompatibility with potential concerns regarding migration, making them potential alternatives to conventional milled ceramics in prosthodontics. However, the potential impact of released residual monomers on soft-tissue healing highlight the need for further optimization and long-term safety evaluations.

A straightforward and digitally integrated technique is described for registering the interocclusal relationship in edentulous patients treated with complete arch implant-supported prostheses. This approach utilizes the patient’s interim denture, adapted over the healing period, as a clinical reference base for transferring occlusal records. The prosthesis preserves the established vertical and centric relationships by selectively relieving the intaglio surface to allow passive seating over healing abutments, followed by intraoral relining. Further modification of the premaxillary region enables clear visualization of the anterior scan bodies during scanning. The relined and digitally modified prosthesis, referred to as the digital interocclusal capture appliance (DICA), is then scanned and incorporated into a digital workflow. This method provides a time-efficient, accurate, and patient-centered solution for transferring occlusal information from the interim removable prosthesis to a refined interim or definitive fixed restoration. It reduces chairside time, minimizes procedural steps, and enhances precision within a digitally guided complete arch workflow.

OBJECTIVES:This study aimed to synthesize silanized cellulose nanocrystals (Si-CNCs) and evaluate their efficacy as reinforcing nanofillers for enhancing the printing accuracy, mechanical properties, and surface quality of dental restorations fabricated via DLP. METHODS:Si-CNCs were synthesized by grafting 3-methacryloxypropyltrimethoxysilane onto CNC surfaces and characterized using DLS, Zeta potential analysis, XPS, XRD, FTIR, TGA, and AFM. Nanocomposite resins were formulated by incorporating CNCs or Si-CNCs (0.1-2 wt%) into a UA matrix. Photopolymerization characteristics were analyzed using UV-Vis transmittance and Jacob's working curve. Printing accuracy was quantified by RMS deviation analysis of 3D-printed crowns and bridges. Mechanical properties, surface roughness, and biocompatibility were also evaluated. The significance level was set at p < 0.05. RESULTS:Characterization confirmed successful silanization. AFM images confirmed that silanization converted CNCs from bundled agglomerates into a homogeneous dispersion. UV-Vis transmittance and Jacob's working curve revealed a concentration-dependent crossover in light extinction between the two series. The Si-CNC system retained dispersion across the full concentration range and stabilized the curing depth. Printing accuracy improved significantly over the UA control and unmodified CNCs (p < 0.05). The 0.5 wt% Si-CNC group achieved the lowest RMS for both the crown (35.48 ± 1.32 µm) and bridge (57.25 ± 4.49 µm) models, with optimal DC, Vickers hardness (25.83 ± 0.69 HV), and tensile strength (47.93 ± 4.77 MPa). Si-CNCs also produced superior surface smoothness and good cell viability. SIGNIFICANCE:Si-CNCs reconcile high printing accuracy with robust mechanical performance in DLP dental resins. This system offers a viable strategy for high-precision dental restorations.

Interprofessional service-learning (IPSL) combines community-based experiential learning with interprofessional education (IPE), fostering collaborative competencies and civic responsibility among students. Despite growing interest, the integration of service-learning and IPE in undergraduate dental curricula remains underexplored. This scoping review was conducted using the Arksey and O’Malley framework and refined by Levac et al., adhering to the PRISMA-ScR guidelines. Several electronic databases (PubMed, Scopus, Web of Science, EBSCO, and EMBASE) were searched from 1960 to March 2025 using a combination of controlled vocabulary and free-text terms. Manual searching of reference lists and grey literature through Google Scholar and institutional repositories supplemented the database searches. Screening and data extraction were conducted by two independent reviewers based on pre-defined inclusion and exclusion criteria. Thematic synthesis was used to analyse and categorise the findings qualitatively. From 1422 records, 11 eligible studies published between 2015 and 2023 were included. Most studies were conducted in the United States, with one from Canada. IPSL interventions occurred in diverse settings, including refugee shelters, rural clinics, prisons, and global health contexts. Dental students engaged with disciplines such as medicine, nursing, pharmacy, public health, social work, law and others. Key themes included ‘Implementation Contexts and Interprofessional Partnerships’, ‘Oral Health Promotion and Prevention’, ‘Oral Health Literacy Outcomes’, ‘Reflective Learning’, and ‘Student Perceptions and Attitudes’. IPSL is an impactful educational strategy for dental students, promoting both clinical and interprofessional development. Future programmes should include structured preparatory training and longitudinal assessment to sustain learning outcomes and enhance the reach of IPSL globally.

This study aimed to determine the effects of the proportion of dimethylaminohexadecyl methacrylate (DMAHDM) nanoparticle to urethane acrylate (UA)-based 3D-printing resin on antibacterial and antifungi activities, biocompatibility, degree of conversion (DC), and mechanical properties. UA-based resin and DMAHDM were synthesized separately and mixed to prepare specimens at DMAHDM proportions of 0–1 wt%. The WST-8 viability assay was used to assess the antibacterial effects against Streptococcus mutans (S. mutans), and the growth of Candida albicans (C. albicans) was measured by OD600 to evaluate antifungal activity. Human gingival fibroblasts were used for biocompatibility assessment via WST-8 and EdU assay. The DC was analyzed using FTIR spectroscopy. Flexural strength, flexural modulus, and Vickers hardness were assessed. One-way ANOVA was performed (α = 0.05). The anti-S. mutans efficacy increased with the DMAHDM concentration, with the bacterial viability significantly decreasing from 85.76±14.78% (mean±standard deviation) at 0 wt% to 56.61±0.60% at 1 wt%. C. albicans growth was also inhibited in a dose-dependent manner, decreasing from 88.77±5.03% at 0 wt% to 44.00±14.72% at 1 wt%. No cytotoxicity was observed but the cell proliferation decreased as the DMAHDM concentration increased. The highest DC was recorded at 1 wt% (57.88±0.83%). The flexural strength was largest (118.59±19.89 MPa) at 0 wt%. The Vickers hardness was highest at 0 wt% (23.03±0.76 HV) and decreased slightly with increasing DMAHDM concentration. DMAHDM-incorporated UA-based 3D-printing resin exhibited strong antibacterial effects against S. mutans and antifungal effects against C. albicans, alongside excellent biocompatibility, improved polymer conversion, and competitive mechanical properties, highlighting its potential for dental applications.

OBJECTIVES:To investigate how different combinations of base monomers, including diurethane dimethacrylate (DUDMA) and bisphenol A-glycidyl methacrylate (Bis-GMA), and diluent monomers, including trimethylolpropane trimethacrylate (TMPTMA) and triethylene glycol dimethacrylate (TEGDMA), as well as their mixing ratios, influence light attenuation behavior, degree of conversion (DC), mechanical properties, and cell viability in dental resins fabricated by layer-wise additive manufacturing. METHODS:Binary systems were formulated at 5:5 and 7:3 wt ratios. Their optical behavior was characterized using Jacob's working curve, while the degree of conversion (DC) was quantified via ATR-FTIR. Mechanical properties and biocompatibility were evaluated using three-point bending tests, Vickers hardness and CCK-8 assays with human gingival fibroblasts, respectively. RESULTS:All formulations exhibited linear working curve behavior. TEGDMA-containing systems showed significantly higher DC and flexural strength, whereas TMPTMA-containing systems demonstrated greater flexural modulus and Vickers hardness. Mixing ratio effects were system-dependent, with no direct correlation between curing behavior, DC, or mechanical properties. All formulations showed no cytotoxicity in human gingival fibroblasts. SIGNIFICANCE:This study provides a comprehensive understanding of how the interplay between base monomers (DUDMA, Bis-GMA) and diluents (TMPTMA, TEGDMA) dictates the performance of 3D-printed unfilled dental resins. By integrating Jacob's working curve analysis with mechanical and biological evaluations, we identified optimal formulations that balance high degree of conversion with clinical-level biocompatibility. These findings offer a precise chemical roadmap for developing next-generation additive manufacturing resins with tailored mechanical properties for restorative dentistry.

This study investigated the gravitational sedimentation of silica nanoparticles in DLP-printed dental resins and assessed its impact on filler distribution, DC, mechanical and surface properties and printing trueness. Dental resin containing 1 wt

OBJECTIVE:To evaluate tightening-stage-dependent rotational behavior of non-engaging abutments according to delivery method, focusing on positioning guides and cement space configuration. MATERIALS AND METHODS:Non-engaging prefabricated abutments were delivered using positioning guides of varying thicknesses or definitive prostheses fabricated with different cement space. Angular deviation was measured after initial hand tightening and subsequent tightening stages. Positional changes across tightening stages were compared among groups to assess positional reproducibility and stability. RESULTS:When positioning guides were used, angular displacement was observed after initial hand tightening; however, no significant additional displacement occurred during subsequent torque application, indicating maintenance of positional reproducibility. Guide thickness did not significantly influence rotational stability. In contrast, definitive prosthesis-assisted delivery demonstrated tightening-stage-dependent rotational behavior that varied with cement space. With a conventional cement space, angular deviation remained comparable to that observed with positioning guides, whereas increased cement space resulted in progressive angular displacement during tightening. Across all groups, rotational stability was more associated with interfacial space control than with material stiffness. CONCLUSIONS:Within the limitations of this study, the rotational behavior of non-engaging abutments was influenced by the delivery method and interfacial space configuration. Positioning guides promoted reproducible seating, whereas increased cement space during definitive prosthesis-assisted delivery compromised rotational stability.

This study investigated the effects of guide thickness, arch span, and storage duration on the dimensional stability and seating accuracy of 3D-printed implant surgical guides. Forty-eight surgical guides were fabricated using stereolithography (SLA) in partial-arch (PA) and full-arch (FA) designs across three thickness levels (2, 3, and 4 mm). The guides were stored for up to 14 days and evaluated at five time points (0, 1, 3, 7, and 14 days). Dimensional changes were quantified using root mean square error (RMSE) and visualized through colormap analysis, and seating accuracy was assessed by model-based mounting analysis. Most dimensional deformation occurred within the first 24 hours, with stabilization thereafter. Among PA guides, the 2-mm-thick group exhibited a pronounced increase in deformation at day 7 (RMSE: 200.14 ± 37.52 µm), whereas 3-mm and 4-mm PA guides remained dimensionally stable throughout the observation period (4-mm at day 14: 45.90 ± 3.73 µm). FA guides showed more consistent RMSE values across thicknesses and time points than PA guides (4-mm at day 14: 65.16 ± 0.47 µm) and maintained consistent seating accuracy throughout the study. Three-way ANOVA revealed significant main effects and interactions among thickness, arch span, and storage duration with respect to both deformation and seating accuracy (p < 0.001). Based on these findings, a minimum guide thickness of 3 mm is recommended, with 4 mm preferred for PA designs, and at least 24 h of post-curing stabilization should be observed before clinical use.

PURPOSE:To evaluate the mechanical and physical properties of three-dimensional (3D)-printed resins containing >50 wt% inorganic fillers, and compare them with a computer-aided design and computer-aided manufacturing (CAD-CAM) nano-hybrid ceramic resin block and a conventional resin-based 3D-printed material. METHODS:3D-printed resins, including an unfilled resin (RP), a high-filler resin containing >50 wt% inorganic fillers (RCP), and a zirconia-containing high-filler resin (>60 wt% inorganic fillers; RZP), as well as a CAD-CAM nano-hybrid ceramic resin block (RCM), were investigated. Biaxial flexural strength, Weibull reliability, surface hardness, water sorption, and solubility were evaluated. Data were analyzed using one-way analysis of variance (ANOVA), followed by Bonferroni post hoc tests (α = 0.05). Weibull probability analysis with 95% confidence intervals was used to determine the characteristic strength and reliability for each material group. RESULTS:The RZP exhibited the highest flexural strength, followed by RCP and RCM, all outperforming the RP. RZP and RCP demonstrated superior absolute strength but greater variability, while RCM demonstrated higher reliability. Vickers hardness was highest in RCM, though both high-filler resins exceeded RP. RZP showed the greatest water sorption, and RCM showed the lowest solubility. Surface and elemental analyses supported differences in fracture behavior and filler composition. CONCLUSIONS:High-filler 3D-printed resins show mechanical performance comparable to that of CAD-CAM nano-hybrid ceramic resin blocks and are promising materials for restorations requiring enhanced strength and durability.

STATEMENT OF PROBLEM:The customization of silica fillers represents a prevailing trend in resin improvements, yet clinicians lack clarity regarding particle size effects when selecting materials for 3-dimensional (3D) printing. PURPOSE:This study aimed to compare the effects of adding monodispersed, nonporous, spherical silica nanoparticles (150 nm) and microparticles (2.0 μm) at 1 to 2 wt% on the mechanical, surface properties, printing trueness, and biocompatibility of 3D printed dental resins, and to characterize the binary mixtures in optimizing filler selection. MATERIAL AND METHODS:A 3D printed resin (NextDent C&B resin, 3D systems) was modified with monodispersed silica particles and fabricated into test specimens. Comprehensive analyses included surface characterization (surface roughness, Ra, n=10; scanning electron microscopy, SEM, and energy-dispersive X-ray spectroscopy, EDS, n=3), degree of conversion (DC, n=10), Vickers hardness (VHN, n=10), flexural strength (FS, n=10), 3D trueness (n=10), and relative cell viability. Statistical analysis included normality testing (Shapiro-Wilk test) and analysis of variance (ANOVA) with Tukey post hoc comparisons to assess differences (α=.05). The 2-way ANOVA examined interactive effects of silica particle size and concentration. RESULTS:Microparticles at 2 wt% increased surface roughness to 142 ±12 nm (82 ±11 nm in the control group) and hardness to 15.45 ±0.24 VHN (15.14 ±0.37 VHN in the control group). The inclusion of nanoparticles at 2 wt% exerted the opposite effects, reducing the surface roughness to 46 ±7 nm, improving DC, and reducing FS to 100.46 ±8.69 MPa (138.23 ±8.29 MPa in the control group). The mixed group showed the highest DC (63.11 ±2.13%) and balanced mechanical properties. At 2 wt%, both particle types reduced printing trueness, with root mean square (RMS) error rising above 100 μm (72.62 ±2.10 μm in the control). All formulations exhibited satisfactory short-term and long-term biocompatibility. CONCLUSIONS:The monodispersed non-porous silica particles modified 3D printed dental resin. Particle size and concentration of silica critically influence resin performance. Microparticles exhibited stronger concentration-dependent effects than nanoparticles, improving VHN, FS, and Ra. Nanoparticles increased DC and resulted in smoother surfaces with lower Ra. Mixed particles offered a balanced performance through synergistic effects.

OBJECTIVE:To determine whether a bone-flattening drill improves implant placement accuracy in static, computer-assisted implant surgery across different ridge morphologies. MATERIALS AND METHODS:Thirty 3-D printed maxillary models, each featuring a flat and a 20° sloped healed ridge, were randomly allocated to three drilling protocol groups (n = 10 models per group, 60 total implants). In the flattening-drill group (FL), bone preparation was performed with a flattening drill followed by the manufacturer's drilling sequence. The initial drill group (IN) began directly with the initial drill and subsequent drilling sequence, while the final drill group (FN) commenced from the final drill. Fully guided surgical templates with resin sleeves were used. Positional accuracy-platform, apex, angular, and depth deviation-was assessed by digital superimposition of planned versus actual implant positions. Statistical analyses were performed using two-way analysis of variance with post hoc comparisons. RESULTS:The FL group demonstrated significantly superior accuracy over the conventional drilling protocols across all parameters. The platform deviation in the FL group (0.36 ± 0.17 mm) was lower than the IN group (0.57 ± 0.21 mm) and FN group (0.99 ± 0.43 mm) (p < 0.001). The angular deviation showed a similar pattern, being 2.92° ± 1.13°, 4.17° ± 1.48°, and 5.95° ± 2.84° in the FL, IN, and FN groups, respectively (p < 0.001). The ridge inclination significantly affected accuracy in the FL and IN groups, while the FN group showed consistently poor accuracy regardless of the ridge morphology. The 95% confidence intervals in the FL group remained within clinically acceptable ranges for both flat and sloped healed ridges. CONCLUSIONS:The use of a bone-flattening drill as an initial drilling step significantly improved the guided implant surgery accuracy compared with conventional protocols. This modification offers a practical solution for achieving predictable implant positioning, especially on sloped ridges, thereby supporting optimal prosthetic outcomes. CLINICAL SIGNIFICANCE:The bone-flattening-drill protocol might provide clinicians with a reliable method for increasing implant placement accuracy to within clinically acceptable ranges and reducing the risks of prosthetic complications and revision procedures. Further in vivo validation is required.

Purpose: This study explored dental students’ perceptions of arranging denture teeth in complete denture cases, the impact of digital support on learning strategies, and differences in their experiences based on whether they had access to digital support. Methods: In this qualitative case study, a total of 14 students were randomly assigned to either the digital or non-digital support group. The digital group performed digital teeth arrangements, followed by manual tooth arrangements, with access to a 3D viewer, 3D-printed model, and instructor feedback. The non-digital group received only instructor feedback. While the sample size was limited, it is consistent with the purpose and depth of exploratory qualitative case study methodology. Results: Students reported that arranging teeth for patient-specific dentures provided authentic learning experiences, deepening their understanding of laboratory and clinical processes while enhancing motivation and responsibility. The non-digital group encountered difficulties in independently applying theoretical concepts and found peer references of limited usefulness, leading to reliance on supervisor feedback and the search for alternative visual resources. In contrast, digital supports enhanced learning by reinforcing prior knowledge, reducing anxiety, improving three-dimensional understanding, and facilitating reflective practice. Effective denture teeth arrangement with digital support relied on sufficient time, instructor guidance, and structured feedback. Conclusions: Denture teeth arrangement enhanced students’ understanding and provided a practical learning experience, while the complexity of the task imposed emotional burdens. Digital support increased students’ confidence and promoted three-dimensional understanding and self-reflection. Strategies have been proposed to enhance the educational effectiveness of combining denture teeth arrangement with digital support.

The effects of heat-assisted vat photopolymerization (HVPP) on the physical and mechanical properties of 3D-printed dental resins, including the morphometric stability of 3D-printed crowns, were investigated. A resin tank was designed to maintain the resin at 30, 40, and 50 ℃ during the 3D printing process. Test specimens were fabricated using a commercial dental resin, with untreated resin serving as the control group. Key properties such as viscosity, curing kinetics, surface microhardness, flexural properties, and dimensional accuracy were evaluated. The viscosity of the resin decreased significantly (P < 0.05) with increasing temperature, thereby enhancing its flow properties. Photo-DSC analysis revealed a 17.58% increase in peak heat flow at 50 ℃, indicating accelerated polymerization. Surface microhardness improved significantly (P < 0.05) with HVPP, though a slight reduction was observed at 50 ℃ compared to that at 30 and 40 ℃. The flexural strength, modulus, and resilience were significantly enhanced (P < 0.05) at higher temperatures, with 50 ℃ yielding the best mechanical properties. However, 3D morphometric analysis showed increased root mean square deviation from the CAD design at elevated temperatures. Our results suggest that HVPP enhances the durability of dental prostheses, although careful optimization of the printing temperature is essential to balance their strength and accuracy.

OBJECTIVE:Although the accuracy of scanning technologies has been extensively explored, a research gap still exists concerning the scanning results of dental impression materials, particularly regarding their color and gloss characteristics. This study aims to evaluate and compare the scanning capabilities of blue-light scanners for various dental impression materials characterized by different colors and gloss levels. METHODS:Blue (B), green (G), red (R), and yellow (Y) dental impression materials were selected for this study. Colorimetric analyses were conducted using a spectrophotometer. The gloss levels of the samples were quantified using a gloss meter. The accuracy and surface detail reproduction of a blue-light scanner were analyzed by scanning impression materials in four different colors. The four-unit crown-bridge model for accuracy analysis was based on International Standardization Organization (ISO) standard 12836. The data measured by the coordinate measuring machine (CMM) served as the gold standard and were used for parameter comparison (height, angle, and distance) and 3D fitting with the scanned files. RESULTS:Surface detail reproduction analyses revealed significant differences among the various groups. Notably, Group B consistently demonstrated superior scanning accuracy across all measurements, indicating its effectiveness as a dental impression material in blue-light scanning applications. Significant differences were observed in the rate of surface detail, angle parameters, and corner height across the various groups (p < 0.05). Additionally, the root-mean-square error values pertaining to trueness exhibited significant disparities in all the specimens (p < 0.05). SIGNIFICANCE:The absence of significant gloss differences across all color variations indicates that color should be evaluated alongside other critical factors when employing blue-light scanners for measurement accuracy.

BACKGROUND:The present study, grounded in the Stress-Adaptation-Growth theory, aims to explore the mental well-being among dental technology students during the post-pandemic period. MATERIALS AND METHODS:A mixed-method approach was employed among undergraduate dental technology students in Malaysia. The Depression, Anxiety, and Stress Scale (DASS-21) was adapted and modified for dental technology students. The content of the questionnaire was validated by two experienced faculty experts. Construct validity and internal consistency were measured. An online survey was created using Google Forms and disseminated to 10 Bachelor of Dental Technology (BDT) students. Meanwhile, qualitative data were obtained through one-on-one semi-structured interviews, employing a phenomenology approach and thematic analysis to explore students' experiences in the new educational landscape. RESULTS:All students answered the survey, predominantly females. Prevalence of depression (60% normal, 10% mild, 30% moderate), anxiety (30% normal, 30% mild, 10% moderate, 10% severe, 20% extremely severe), and stress (70% normal, 10% mild, 10% moderate, 10% severe) was reported. Qualitatively, three major themes emerged: "Problems with adaptations", "Anxious about returning to campus", and "Concern about the future". The first theme included sub-themes: "Difficulties in transitioning to hybrid learning" and "Disruption in study-life balance". The second theme had four sub-themes: "Fear of being infected", "Fear of being stigmatized", "Increased vigilance in personal safety measures", and "Confusion about standard operating procedure". The third theme included sub-themes: "Fear of another lockdown" and "Concerns about timely completion of academic requirements". CONCLUSIONS:This study highlights the complex mental health challenges dental technology students faced post-pandemic, underscoring the need for flexible academic policies, global collaborations, and targeted strategies to support their resilience and well-being.

PURPOSE:Supports are essential for ensuring dimensional accuracy in 3D printing; however, an excessive number of supports compromises printing efficiency. This study aimed to investigate how a varying number of support arrangements affects the precision and trueness of 3D-printed dentures. METHODS:Three denture base printing files were designed, each with different numbers of supports: 40 (group 40), 55 (group 55), and 70 (group 70). Thirty samples were printed and measured across the groups. Accuracy was evaluated by assessing trueness and precision using the root mean square error (RMSE). The error areas in each group were analyzed through micro-computed tomography (micro-CT) 3D imaging. RESULTS:Group 70 showed a significantly lower RMSE for trueness than Group 40 (P < 0.05), but showed no significant difference from Group 55 (P ≥ 0.05). For precision, Group 70 outperformed both Groups 40 and 55 (P < 0.05), which did not differ significantly (P ≥ 0.05). Micro-CT revealed no mismatches in the palatal region. Discrepancies-areas where the supports in Groups 40 and 55 did not accurately align with those in Group 70-were predominantly observed at initiation points of overhangs in thinner sections. CONCLUSIONS:Based on these results, this study recommends placing support structures strategically around overhangs and thin-walled areas to enhance the accuracy of 3D-printed denture fabrication. These findings indicate that optimizing support placement, rather than merely increasing the number of supports, is crucial in improving the quality and reliability of 3D-printed dental prostheses.

This article describes a straightforward technique for transferring information from an existing, well-adapted implant-supported interim restoration to a definitive prosthesis for edentulous patients. This approach reduces the need for additional procedures typically associated with conventional or digital scanning techniques while maintaining accuracy. By using the patient's functioning interim restoration as pick-up impression copings, this procedure directly transfers critical information about the vertical dimension of occlusion, occlusal relationship, and soft tissue contour in a single appointment.

While innovative designs combining the advantages of screw and cement retention provide both retrievability and passive fit for implant-supported fixed dental prostheses, retrieval becomes challenging with nonparallel implants because of deeper hexagon engagement and antirotational features. This dental technique introduces a sequential intraoral cementation approach to address this limitation. The technique involves engaging each abutment to its hexagon intraorally by cementing the prosthesis first to the most angled implant, removing it extraorally to clean excess cement, and modifying the abutment hexagon into a nonengaging type. Subsequently, the remaining prosthesis is cemented to favorably angled abutments, ensuring both passivity and retrievability. This approach compensates for fabrication discrepancies and enhances the retrievability of these prostheses involving implants with varying angulations, ultimately improving patient comfort and long-term prosthesis maintenance.

PURPOSE:This study aimed to determine the impacts of thermal aging on the mechanical properties, biocompatibility, and antibacterial effectiveness of a urethane acrylate-based (UA) 3D printing resin containing dimethylaminohexadecyl methacrylate (DMAHDM). METHODS:DMAHDM was synthesized and incorporated into UA resin at 0.25 wt%, 0.5 wt%, 0.75 wt%, and 1 wt%. Specimens were 3D printed, washed, post-cured, and thermal cycled at 5 °C and 55 °C for 833, 2500, and 5000 cycles. The group without DMAHDM or aging was considered as the control group. Degree of conversion (DC), color differences, antibacterial effectiveness, cell viability, and mechanical properties were evaluated. Two-way analysis of variance was performed with a significance cutoff of α = 0.05. RESULTS:DC increased with the DMAHDM concentration, with the highest DC being observed at 1 wt% (53.68 ± 0.35 %) (mean ± standard deviation). The color of the specimens showed significant changes after 2500 and 5000 cycles. Antibacterial effectiveness was improved with 0.75 wt% and 1 wt% DMAHDM. Cytotoxicity was observed with prolonged thermal aging cycles. Flexural strength decreased with increasing DMAHDM concentrations and aging, with the lowest values at 1 wt% (93.02 ± 17.96 MPa) after 5000 cycles. However, Vickers hardness significantly increased with both DMAHDM and aging, reaching a peak at 5000 cycles (24.49 ± 0.96 HV). CONCLUSIONS:DMAHDM concentration and thermal aging significantly influenced UA-based 3D printing resins properties. Higher DMAHDM concentration enhanced antibacterial effectiveness and Vickers hardness yet reduced flexural strength after 0.75 wt%. Thermal aging decreased flexural strength while improving DC and hardness. Prolonged aging also led to color changes and increased cytotoxicity.