Search Results (391)

The surgical management of extremity bone defects, particularly post-traumatic nonunion wounds, remains a challenge. Vascularized bone flaps (VBFs), widely used for mandibular reconstruction in head and neck oncologic surgery, are less established in extremity reconstruction and are typically performed freehand, which has several limitations. In the past decade, virtual surgical planning (VSP) and computer-aided design and modeling (CAD-CAM) technology have enabled patient-specific 3D-printed models to guide reconstruction. While this technology has been used extensively in head and neck reconstructive surgery, its application to extremity reconstruction is less well-documented. This case series evaluates the feasibility, safety, and surgical utility of VSP and in-house CAD-CAM manufacture of 3D-printed models and cutting guides for post-traumatic non-healing extremity reconstructions using VBFs. Eight patients at a single tertiary academic center underwent VBF reconstruction guided by patient-specific models and cutting guides, with cases grouped into categories (humerus, femur, and tibia). The multi-disciplinary workflow supported preoperative visualization, osteotomy planning, and intraoperative execution. All vascularized flaps survived, and radiographic union was documented in patients with adequate follow-up. These findings suggest that integrating VSP and CAD-CAM into trauma-associated VBF extremity reconstruction is feasible and safe and may improve reconstructive accuracy and enhance multi-disciplinary team workflow, potentially contributing to improved clinical outcomes. Full article

Accurate transfer of implant position is essential for implant-supported prosthodontic workflows. This in vitro study compared the trueness and precision of five intraoral scanners in single crown, three-unit fixed partial denture, and full-arch implant-supported scanning scenarios using root mean square (RMS) deviation analysis. Two maxillary resin models, representing partially dentulous and fully edentulous conditions, were fabricated through a CAD/CAM and 3D-printing workflow with implant analogs and scan bodies. Reference datasets were obtained with an InEos X5 desktop scanner, and each intraoral scanner was used to perform 10 scans per scenario. After standardized scenario-specific trimming, datasets were analyzed in Geomagic Control X. Statistical analysis included two-way analysis of variance and follow-up one-way analysis of variance with Tukey post hoc comparisons using Bonferroni-adjusted thresholds. Trueness was affected by scanner type (p < 0.001) and scenario (p < 0.001), without interaction (p = 0.096). Precision was affected by scanner type (p = 0.012), scenario (p = 0.004), and their interaction (p < 0.001). iTero Lumina and Helios 600 showed lower trueness deviations, whereas Trios 5 showed greater deviations, especially in full-arch scans. Scanner selection and scan extent should therefore be considered when interpreting surface-based RMS accuracy in implant-supported digital scans. Full article

Background: Advances in additive manufacturing and CAD/CAM technologies have expanded the use of 3D-printed orthodontic models in digital aligner workflows. Intraoral scanners (IOS) are critical for accurately capturing attachment geometries and dental morphology during these workflows. However, comparative evidence regarding IOS accuracy in models with complex orthodontic structures remains limited. Therefore, this study aimed to compare the trueness and precision of five IOS using 3D-printed orthodontic models with attachments. Methods: In this in vitro study, thirty independent single-arch 3D-printed models (either maxillary or mandibular) with orthodontic attachments were scanned twice with each IOS. The Smart Optics Vinyl laboratory scanner served as the reference scanner. Scans were aligned and superimposed in CloudCompare, and root mean square (RMS) deviation values were calculated to evaluate accuracy. Nonparametric Kruskal–Wallis and Dunn tests were applied (α = 0.05). Results: Significant differences were found among scanners for both trueness and precision (p < 0.001). Primescan, TRIOS 3, and iTero element 5D demonstrated comparable trueness (p > 0.05) and outperformed Rapideye MI-1000 (p < 0.001). iTero element 2 plus showed slightly lower accuracy but remained clinically acceptable. Primescan achieved the highest precision, significantly exceeding iTero element 2 plus, iTero element 5D, and Rapideye MI-1000 (p < 0.01). TRIOS 3 also exhibited excellent repeatability, comparable to Primescan (p = 1.000). Conclusions: All intraoral scanners, except Rapideye MI-1000, demonstrated accuracy levels generally considered clinically acceptable for digital orthodontic and additive manufacturing workflows. Primescan, TRIOS 3, and iTero element 5D exhibited similarly high trueness, while Primescan showed the most consistent precision. The ability of these scanners to reproduce fine anatomical details may improve the reliability of 3D-printed orthodontic models and in-office aligner production workflows. Full article

Multilayer 4Y/5Y-PSZ zirconia materials have been developed to combine strength and translucency in monolithic “all-in-one” dental restorations. This study evaluated the flexural strength of different layers (incisal, transition, and dentin) in four commercially available multilayer zirconia systems using three-point bending tests in accordance with ISO 6872. A total of 360 CAD/CAM-fabricated bar-shaped specimens were prepared from the materials CE (Cercon yo ML, DentsplySirona), KA (Katana YML, Kuraray Noritake), PZ (3D ProZir, Aidite), PE (IPS e.max ZirCAD Prime esthetic), and assigned to layer-specific groups based on their position within the discs. After sintering and standardized surface finishing, specimens were tested under three-point bending conditions. Fracture strength was calculated and statistically analysed. Microstructural and fractographic analyses were performed to assess grain structure and to identify fracture origins. The results demonstrated significant differences in flexural strength both among materials and between layers. In general, dentin layers exhibited the highest strength, reaching mean values up to 1143 MPa, while incisal layers showed significantly lower values, with minima around 572 MPa. Only one material (CE) maintained flexural strength above the ISO threshold of 800 MPa across all layers, qualifying for unrestricted (class 5) clinical use. Other materials showed limitations, particularly in the more translucent incisal regions (KA, PE). One material fell below the ISO threshold (PZ). Weibull moduli revealed differences in reliability, with moduli ranging from 4.7 to 16.5. Fractographic evaluation identified typical fracture patterns such as surface grinding defects and internal porosity, but no abnormal fracture origins. The strength gradient corresponds to microstructural differences, particularly grain size and phase composition, influenced by yttria content. Increased translucency in incisal layers is associated with reduced mechanical performance. These findings emphasize that, despite aesthetic advantages, layer-dependent strength variations must be considered when selecting multilayer zirconia for clinical applications, especially in long-span restorations. Full article

To investigate the effect of print orientation (0°, 45°, and 90°) and artificial aging on flexural strength and fatigue resistance of 3D-printed denture bases compared to CAD/CAM milled controls, we fabricated 320 maxillary complete dentures, divided into 8 groups based on the fabrication method: horizontal, oblique, and vertical printing, alongside milled controls. Half of the specimens in each group were pre-conditioned via thermocycling and 240,000 cycles of chewing simulation. All specimens underwent static flexural strength testing and cyclic fatigue testing, followed by SEM fractography. The CAD/CAM milled bases demonstrated the highest mechanical durability, with non-aged specimens peaking at 149.43 ± 5.35 MPa. The horizontally 3D-printed non-aged specimens yielded the highest flexural strength (101.14 ± 4.80 MPa), while vertically printed aged specimens recorded the lowest (70.35 ± 8.18 MPa). Artificial aging degraded flexural strength uniformly across all orientations. Conversely, cyclic loading disproportionately devastated the older people’s vertical group, resulting in a 70% fracture rate. Fractography corroborated these findings, revealing severe interlaminar delamination in vertical builds, contrasting with cohesive, trans-layer fractures in horizontal prints. In conclusion, Horizontal orientation provided improved structural durability; however, CAD/CAM milled dentures remain superior and are recommended for long-term clinical applications. Full article

This study aimed to investigate the repair performance of these materials subjected to different surface treatment protocols using combined mechanical and optical evaluations. Four resin-matrix materials were evaluated: two CAD/CAM materials (HIPC Plus and GC Cerasmart) and two additively manufactured resins (VarseoSmile TriniQ and CrownTec). Standardized disc specimens were fabricated and thermocycled prior to repair. Three surface treatments were applied: airborne particle abrasion (APA), tribochemical silica coating (TSC) with silane, and laser treatment (LT). Micro-shear bond strength (µSBS) was measured using composite cylinders bonded to treated surfaces. For optical evaluation, standardized cavities were restored with composite resin, and color measurements were obtained at baseline (T0) and after aging (T1) using a spectrophotometer. Color mismatch and color stability were calculated. Data were analyzed using two-way ANOVA and Tukey tests (α = 0.05). Material type and surface treatment significantly affected µSBS (p < 0.001). CAD/CAM materials had higher bond strength than additively manufactured ones. The TSC group showed the highest µSBS. Aging increased color mismatch, with post-aging ΔE00 values surpassing clinical thresholds. Additively manufactured materials experienced greater color changes. Repair performance depends on manufacturing method and surface treatment. The higher bond strength in the TSC group likely results from silica coating and silanization. CAD/CAM materials showed better optical stability. Full article

Background/Objectives: The growing adoption of digital technologies in prosthodontics has led to the widespread use of computer-aided design and computer-aided manufacturing (CAD/CAM) and three-dimensional (3D) printing for dental prostheses. However, differences in mechanical performance, particularly flexural strength and fracture resistance, remain a concern. Objective: To systematically evaluate and compare the flexural strength and fracture resistance of milled CAD/CAM and 3D-printed dental prostheses. Methods: A systematic review and meta-analysis were conducted following PRISMA 2020 guidelines. A comprehensive search was performed across multiple databases, including PubMed, Scopus, Web of Science, and Cochrane Library. In vitro studies comparing milled and 3D-printed prosthetic materials were included. Data extraction and risk of bias assessment were performed independently by multiple reviewers. A random-effects meta-analysis using standardized mean differences (SMD) was conducted. Results: Five studies were included in the meta-analysis for flexural strength. Milled CAD/CAM materials demonstrated significantly higher flexural strength compared to 3D-printed resins (SMD = 3.70; 95% CI: 0.80–6.59; p = 0.012), with substantial heterogeneity (I² = 93.3%). Fracture resistance results were inconsistent and influenced by individual studies, with sensitivity analyses showing variability in pooled estimates. Overall, the risk of bias was considered low, although some concerns were identified in randomization and blinding. Conclusions: CAD/CAM-milled materials exhibit superior flexural strength, while fracture resistance outcomes remain variable. Although 3D-printed materials may be clinically acceptable, further standardized studies are required to confirm their mechanical reliability. Full article

Background/Objectives: Wettability is a key surface property of denture base resins and is related to denture retention through interfacial cohesive–adhesive forces; conversely, compromised material wettability facilitates bacterial adhesion and colonization. Although three-dimensional (3D) printing has become an increasingly popular method for fabricating dentures, there is insufficient evidence regarding the wettability of 3D-printed denture base resins. This study aims to evaluate the wettability of 3D-printed, heat-polymerized, and milled denture base resins by comparing their contact angles. Methods: A search was conducted in MEDLINE, Scopus, and Web of Science, while grey literature was also assessed. The risk of bias was evaluated using the Quality Assessment Tool for In Vitro Studies (QUIN). Meta-analyses were conducted using inverse variance and the random effects model. Results: A total of nine and seven studies were included in the quantitative synthesis comparing 3D-printed denture base resins with heat-polymerized and milled resins, respectively. A statistically significant difference of −6.50 degrees was observed in favor of 3D-printed denture base resins compared to heat-polymerized ones (95% CI: −12.11 to −0.90, I² = 99%), while the comparison between 3D-printed and milled resins showed a non-statistically significant mean difference (MD: 0.87, 95% CI: −5.08 to 6.82, I² = 98%). Conclusions: The available in vitro evidence indicates that 3D-printed denture base resins tend to exhibit improved surface wettability compared with heat-polymerized resins and perform similarly to milled resins. However, given the extremely high heterogeneity, these findings should be interpreted with caution, as clinical performance depends on the complex interplay between surface characteristics and microbial adhesion rather than solely on wettability. Full article

Background: Digital fabrication techniques such as CAD/CAM milling and 3D printing are widely used for provisional dental restorations. However, differences in mechanical performance remain controversial. Objective: To compare the hardness and flexural strength of CAD/CAM-milled resins versus 3D-printed resins used in restorative dentistry. Methods: A systematic review and meta-analysis were conducted following PRISMA 2020 guidelines and registered in PROSPERO (CRD420251045547). Electronic searches were performed in PubMed, Scopus, Web of Science, Embase, and LILACS. In vitro studies comparing CAD/CAM-milled and 3D-printed resins in terms of hardness and/or flexural strength were included. A random-effects inverse-variance model was applied using standardized mean difference (SMD) with 95% confidence intervals (CI). Risk of bias was assessed using the RoB-Iv tool. Results: Four studies (n = 124 specimens) were included in the hardness meta-analysis. CAD/CAM-milled resins showed significantly higher hardness (SMD = 2.92; 95% CI: 0.34–5.49; p = 0.026), although heterogeneity was high (I² = 94.9%). Funnel plot asymmetry suggested possible small-study effects. For flexural strength, three studies (n = 40 specimens) were analyzed, demonstrating a significant effect favoring milled resins (SMD = 1.28; 95% CI: 0.42–2.14; p = 0.0036) with low-to-moderate heterogeneity (I² = 27.8%). Sensitivity analyses confirmed robustness for both outcomes. Overall methodological quality was acceptable, with no high risk of bias identified in strength studies. Conclusions: CAD/CAM-milled resins tend to demonstrate higher hardness and flexural strength compared with 3D-printed resins. However, the substantial heterogeneity observed, particularly for hardness, and the potential influence of methodological variability, warrant cautious interpretation of these findings. Full article

Background/Objectives: The present study aims to test three different types of PMMA (Fotodent Guide—3D printed (M1), Aidite Temp—milled (M2), Duracryl—self-polymerized (M3) on HFIB-G and on OECM-1. Methods: The two cell types (HFIB-G and OECM-1) were kept in contact with the materials, Fotodent Guide, Aidite Temp, and Duracryl (n = 6), for 24 and 48 h, and subsequently subjected to the following tests: MTT, LDH, NO (according to ISO 10993-5:2009), and immunofluorescent detection of proteins associated with autophagy and apoptosis (mitochondria and caspases 3/7; detection of autophagosomes). Statistical interpretation was made using t-test and ANOVA (* p < 0.05; ** p < 0.01; *** p < 0.001). Results: The MTT assay revealed a reduction in cell viability for all tested materials on gingival fibroblasts compared to control cells, with the most pronounced decrease observed for the 3D-printed material (M1 viability 66.77% for 24 and 52.45% 48 h—p < 0.001), while the self-polymerizing resin (M3 viability 85.92% for 24 h and 85.63% for 48 h) showed the highest level of cellular tolerance (p < 0.001 at 24 h and p < 0.01 at 48 h). Regarding OECM-1 cells, all materials reduced cell viability, particularly M3 after 48 h of incubation (viability 61.79%—p < 0.001). LDH levels generally indicated low membrane damage for all materials. Statistically significant increases in NO levels were recorded for both cell types, suggesting a mild proinflammatory response, especially for M2 OECM-1 48 h—p < 0.05 and M3 (HFIB-G 48 h—p < 0.05, OECM-1 48 h p < 0.05). For both 24 and 48 h, fluorescence analysis demonstrated a significant increase in mitochondrial activity in gingival fibroblasts (p < 0.001), whereas tumor cells exhibited a significantly decreased mitochondrial activity (p < 0.001), particularly for the 3D-printed material M1 (p < 0.001). Caspase-3/7 expression increased in gingival fibroblasts incubated with materials for 24 and 48 h (p < 0.001), while tumor cells showed reduced caspase activity both after 24 and 48 h (p < 0.001). Autophagosome formation decreased initially in fibroblasts at 24 h (p < 0.001) but increased significantly after 48 h (p < 0.001), while tumor cells generally showed enhanced autophagic activity under most experimental conditions (p < 0.001). Conclusions: Our results suggest that all three PMMA-based materials exhibit acceptable biocompatibility profiles, of more than 70%, according to ISO 10993-5:2009, although cellular responses vary depending on the manufacturing technique and the cellular model used. In our study conditions, self-polymerized resin (M3) was the most compatible with gingival fibroblasts, while the 3D-printed and CAD/CAM milled materials (M1 and M2) had a more pronounced impact on cells’ viability and metabolic activity. Full article

This study quantified projection-dependent geometric distortion induced by vertical camera angulation in two-dimensional (2D) dental image acquisition and evaluated its implications for integration with three-dimensional (3D) CAD/CAM and artificial intelligence (AI)-driven workflows. To our knowledge, this study is among the first to use quantitative methods to characterize projection-induced distortion across the dental arch as a function of vertical camera angulation. Fourteen fully dentate casts were photographed at nine standardized vertical angulations using a controlled acquisition setup based on the standardized occlusal plane angle (SOPA). Tooth surface areas were measured through digital tracing and analyzed with a mixed-effects model (α = 0.05). Significant associations were identified between vertical camera angulation and measured tooth surface area for all teeth except canines (p < 0.05 for all except canines). Anterior teeth demonstrated increased apparent surface area at superior camera angulations, whereas posterior teeth were more prominently represented at inferior angulations. Central incisors, lateral incisors, and first premolars exhibited maximal visibility above the occlusal plane, while second premolars and molars were more optimally visualized below it. These findings indicate that vertical camera angulation induces non-uniform, region-specific geometric distortion across the dental arch. From a computational perspective, these distortions represent a systematic source of variability in 2D photographic datasets used in CAD/CAM workflows, virtual smile design, and AI-assisted image analysis. Because modern machine learning systems depend on geometrically consistent input data, uncorrected projection-induced distortion may reduce the reliability and generalizability of downstream algorithmic outputs. Accordingly, the present findings establish a quantitative basis for recognizing projection-induced variability in 2D dental photographs and support future development of geometry-aware calibration strategies for 2D-3D digital integration. AI-assisted correction represents a future translational direction contingent upon explicit alignment between acquisition geometry, image formation, and computational modeling. Full article

This case report describes a digital workflow for the aesthetic rehabilitation of a 30-year-old male patient with unaesthetic anterior teeth. The treatment incorporated AI-assisted smile design software (SmileCloud Biometrics) for 2D/3D digital planning and patient communication. Six lithium disilicate veneers (IPS e.max CAD) were fabricated using CAD/CAM technology following mock-up-guided minimally invasive preparation (0.2–0.9 mm reduction). The restorations were adhesively cemented under rubber dam isolation. One-week follow-up confirmed aesthetic integration, occlusal harmony, and patient satisfaction. This case illustrates how digital workflows with AI-assisted tools can support veneer rehabilitation through data-informed planning and conservative preparation while maintaining aesthetic outcomes. Full article

This in vitro study evaluated the effects of whey protein isolate and concentrate on surface roughness, color stainability, and translucency of 3D-printed definitive resins. Five 3D-printed resins were tested: Alias Dental Crown (AC), Crowntec (CT), Permanent Crown Resin (PC), VarseoSmile Crown^plus (VSC), and VarseoSmile TriniQ (VST) (n = 30). Each material was subdivided into groups (n = 10), and the same specimens were evaluated at baseline, after 3 and 14 days of immersion in distilled water, whey protein isolate, or whey protein concentrate. Surface roughness (Ra) was measured with a contact profilometer, while color stainability (ΔE₀₀) and translucency (ΔRTP₀₀) were assessed using a spectrophotometer. Surface roughness was not significantly affected by solution type, with minor material-specific increases limited to AC and VST (p = 0.001). Color stainability differed significantly among solutions (p = 0.001) and increased significantly between 3 and 14 days (p = 0.001), with whey protein concentrate producing the greatest discoloration. At 14 days, AC demonstrated the highest ΔE₀₀, followed by CT, while PC, VSC, and VST showed comparable performance. Translucency changes differed significantly among materials (p = 0.001), with AC exhibiting the lowest ΔRTP₀₀ in protein solutions, exceeding the perceptibility threshold but remaining below the acceptability threshold. Whey protein shakes increased color stainability of certain resins, with AC, CT, and VST exceeding the color acceptability threshold (AT₀₀ = 1.81), while surface roughness changes were limited and translucency remained within the acceptability threshold for all materials. Full article

Three-dimensional (3D) printing is increasingly used for the fabrication of definitive crowns; however, whether specific post-curing hardware is mandatory for clinical success remains a practical concern. This study provided a practical comparison evaluating the effect of two post-curing units on the biaxial flexural strength (BFS), Weibull modulus (m), Martens hardness (HM), indentation modulus (EIT), water sorption (WSP), and water solubility (WSL) of 3D-printed resins for permanent crowns, compared with a conventional resin composite. A total of 200 specimens were fabricated from two 3D-printed resins (Permanent Crown™ and CrownTec™) and a conventional resin composite (Filtek Universal Restorative™) used as a control. The 3D-printed specimens were post-cured using either a Formcure or an Otoflash G171 unit. WSP and WSL were measured after 90 days of water ageing, while BFS, HM, and EIT were evaluated after 24 h of storage using standardised methods. All materials exhibited WSP and WSL values within ISO limits, with the control group showing significantly higher values and superior mechanical properties. Among the 3D-printed resins, post-curing significantly affected only HM and EIT for Permanent Crown™ resin, with no significant differences in BFS. Overall, the tested 3D-printed resins demonstrated high processing stability across different curing protocols, suggesting that clinical performance remains consistent regardless of the post-curing unit used. Full article

Background: Achieving facial harmony in patients with micrognathia requires precise chin augmentation. While conventional ready-made implants often fail to conform to unique mandibular surfaces, expensive patient-specific options like PEEK or Titanium lack intraoperative adjustability. We introduce an innovative, cost-effective workflow utilizing 3D-printed templates to fabricate customized Polymethyl Methacrylate (PMMA) implants, emphasizing their clinical feasibility and intraoperative versatility. Methods: We retrospectively analyzed 20 patients with mild-to-moderate micrognathia (<6 mm advancement) who underwent genioplasty between March 2021 and June 2022. Patient-specific templates were produced via Fused Deposition Modeling (FDM) using low-shrinkage Acrylonitrile Butadiene Styrene (ABS) filament. During surgery, final PMMA implants were molded using these sterilized templates. Accuracy was evaluated by comparing mental advancement across preoperative, virtual simulation, and 6-month postoperative stages using Vectra 3D scanning. Results: Quantitative analysis revealed high fidelity between virtual planning and clinical outcomes. The mean discrepancy in horizontal advancement was only 1.02 mm (Planned: 5.04 mm vs. Actual: 4.02 mm). Statistical analysis showed a strong positive correlation (r = 0.928, p = 0.001). Subjective patient satisfaction was high, with 90% reporting “exceptional” or “very improved” results on the Global Aesthetic Improvement Scale (GAIS). Two cases of transient numbness resolved spontaneously within two months. Conclusions: This workflow combines FDM-based template fabrication with intraoperative PMMA molding, enabling real-time adjustment of implant geometry. The results demonstrate a high level of agreement between virtual planning and postoperative outcomes, supporting the clinical reliability of this approach. It may serve as a practical alternative to conventional CAD/CAM methods, particularly in cases requiring both precision and intraoperative flexibility. Full article