Search Results (580)

(1) Objective: To compare the marginal and internal fit of 3D-printed and milled three-unit fixed dental prostheses (FDPs) made from tetragonal zirconia polycrystal (3Y-TZP). (2) Methods: Three-unit FDPs were designed for a typodont maxillary model with crown preparation for the second premolar and second molar. Nominal cement gap widths were set to 30 µm at the margins and 80 µm internally. A total of 40 FDPs (n = 10/group) differing in wall thickness (w = 0.6/1.0 mm) and support structures (with/without a stiffening frame) were fabricated from 3Y-TZP by 3D printing. A total of 10 milled FDPs with w = 0.6 mm served as a control group. After adhesive cementation on the respective replicated maxillary models, FDPs were sectioned and the cement gap dimension was assessed with a digital microscope. The marginal and internal fit found for the different test groups were compared using non-parametric tests. (3) Results: The best marginal fit—qualified by median/ maximum marginal gap width—was given for milled FDPs (79/127 µm vertical; 85/171 µm tangential), whereas the marginal fit of 3D-printed FDPs with w = 0.6 mm and regular support structures was the worst (144/284 µm vertical; 107/198 µm tangential). Use of an additional support frame improved the marginal fit of 3D-printed FDPs, in particular FDPs with w = 0.6 mm (108/197 µm vertical; 87/161 µm tangential). (4) Conclusions: 3D-printed zirconia FDPs showed conditionally comparable marginal and internal fit as their milled counterparts, but with slightly higher scattering. When fabricating thinner 3D-printed FDPs, additional support structures are mandatory to achieve clinically well-fitting restorations. Full article

Lanthanide-based single-molecule magnets are promising candidates for potential applications. Their magnetism is governed by ligand-field splittings, which may require up to 27 ligand-field parameters for accurate modeling. Determining these parameters reliably from measured data is a major challenge, for which machine learning approaches offer promising solutions. We provide an overview of these approaches and present our perspective on addressing the inverse problem relating experimental data to ligand-field parameters. Previously, a machine learning architecture combining a variational autoencoder (VAE) and an invertible neural network (INN) showed promise for analyzing temperature-dependent magnetic susceptibility data. In this work, the VAE-INN model is extended through data augmentation to enhance its tolerance to common experimental inaccuracies. Focusing on second-order ligand-field parameters, diamagnetic and molar-mass errors are incorporated by augmenting the training dataset with experimentally motivated error distributions. Tests on simulated experimental susceptibility curves demonstrate substantially improved prediction accuracy and robustness when the distributions correspond to realistic error ranges. When applied to the experimental susceptibility curve of the complex ${\mathrm{Al}}_2^{\mathrm{III}}$${\mathrm{Er}}_2^{\mathrm{III}}$, the augmented VAE–INN recovers ligand-field solutions consistent with least-squares benchmarks. The proposed data augmentation thus overcomes a key limitation, bringing the ML approach closer to practical use for higher-order ligand-field parameters. Full article

Reconstructing original cusp dimensions in worn molars represents a fundamental challenge across dentistry, anthropology, and paleontology, as dental wear obscures critical morphological information. In this proof-of-concept study, we present a standardized machine learning pipeline for predicting original cusp height, specifically the horn tips of the enamel–dentine junction (EDJ), in worn lower molars using three-dimensional morphometric data from micro-computed tomography (micro-CT). We analyzed 40 permanent lower first (M1) and second (M2) molars from four hominin groups, systematically evaluated across three wear stages: original, moderately worn (worn1), and severely worn (worn2). Morphometric variables including height, area, and volume were quantified for each cusp, with Random Forest and multiple linear regression models developed individually and combined through ensemble methods. To mimic realistic reconstruction scenarios while preserving a known ground truth, models were trained on unworn specimens (original EDJ morphology) and tested on other teeth after digitally simulated wear (worn1 and worn2). Predictive performance was evaluated using root mean square error (RMSE) and coefficient of determination (R²). Our results demonstrate that under moderate wear (worn1), the ensemble models achieved normalized RMSE values between 11% and 17%. Absolute errors typically below 0.25 mm for most cusps, with R² values up to ~0.69. Performance deteriorated under severe wear (worn2), particularly for morphologically variable cusps such as the hypoconid and entoconid, but generally remained within sub-millimetric error ranges for several structures. Random Forests and linear models showed complementary strengths, and the ensemble generally offered the most stable performance across cusps and wear states. To enhance transparency and accessibility, we provide a comprehensive, user-friendly software pipeline including pre-trained models, automated prediction scripts, standardized data templates, and detailed documentation. This implementation allows researchers without advanced machine learning expertise to explore EDJ-based reconstruction from standard morphometric measurements in new datasets, while explicitly acknowledging the limitations imposed by our modest and taxonomically unbalanced sample. More broadly, the framework represents an initial step toward predicting complete crown morphology, including enamel thickness, in worn or damaged teeth. As such, it offers a validated methodological foundation for future developments in cusp and crown reconstruction in both clinical and evolutionary dental research. Full article

Management of maxillomandibular transverse discrepancy (MTD) is essential for achieving stable, functional, and esthetic occlusion. This study aimed to evaluate the maxillomandibular transverse dimensions and discrepancies in relation to vertical skeletal patterns using digital dental casts and cone-beam computed tomography (CBCT) images. A total of 180 untreated adult subjects were classified into three vertical groups based on the SN-MP angle: hypodivergent (<27°), normovergent (27–37°), and hyperdivergent (>37°), with 60 subjects in each group. Dental arch widths using casts (DAWs-Casts) were measured at the canine, first premolar, first molar, and second molar, while basal arch widths using casts (BAWs-Casts) were measured at the mucogingival junction apical to the corresponding cusp tips. CBCT images were used to measure basal arch widths (BAWs-CBCT) at the estimated centers of resistance (CRes). DAW-Cast, BAW-Cast, and BAW-CBCT measurements were affected by vertical skeletal patterns. Therefore, maxillomandibular dimensions and discrepancies vary according to vertical skeletal pattern, underscoring the need for careful evaluation when planning treatment protocols for patients with MTD. Full article

A common cause of teeth malocclusion and feeding disorders in guinea pigs is macrodontia and odontogenic abscesses. If the maxillary second or third molar teeth are affected, surgical access to them has so far been achieved through enucleation or orbital evisceration due to their location at the base of the orbit. The study aims to demonstrate a transorbital surgical approach to the apices of the maxillary molar teeth (M2 and M3) in guinea pigs, allowing preservation of the eye. Twenty six apicoectomies of maxillary M2 and M3 were performed. The surgical approach involved a skin incision above the zygomatic arch, followed by soft tissue dissection, incision of the orbital ligament, and gentle dorsolateral displacement of the eyeball. Blunt dissection between the lacrimal and zygomatic glands provided direct access to the affected tooth apices, which were removed using a dental bur. After the procedure, the soft tissues and the eye were repositioned and the skin was sutured. All animals recovered uneventfully. The described method may be applied in cases where it is necessary to perform maxillary second and/or last molar tooth apicoectomy while avoiding damage to the eyeball. Care must be taken to protect the corneal surface of the affected eye. Full article

Background: Dens invaginatus is a rare developmental tooth anomaly that can occur in permanent, primary, and supernumerary teeth, with a tendency to affect the maxillary second incisors. It develops during odontogenesis due to the invagination of the enamel organ into the dental papilla. Methods: This study describes the endodontic management of a 24-year-old patient with a type IIIb invaginated tooth in the mandibular second molar. Clinical examination revealed no response to thermal and electrical stimuli, no response to vertical and horizontal percussion, and no pathological mobility. The depth of the gingival pocket was 8 mm. Root canal therapy was performed over three sessions. The patient remained asymptomatic during the treatment and follow-up visits. Results: Radiographs at 4-, 6-, and 9-month post-treatment showed healing of the periapical lesion. Conclusions: Due to the complex canal anatomy of invaginated teeth, confirming the diagnosis with cone-beam computed tomography (CBCT) is essential. Treating invaginated teeth presents significant challenges for clinicians, requiring a thorough understanding of the dental anatomical variability, advanced manual skills, and the use of specialized equipment. Full article

Background: Missed second mesiobuccal second (MB2) canals are a recognized contributor to endodontic failure, and enhanced visualization may facilitate their detection. This study evaluated the influence of magnification devices and operator experience on MB2 detection using anatomically standardized 3D-printed maxillary first molar models. Methods: Fifty-nine endodontists and endodontic residents evaluated anatomically standardized TrueTooth® 3D-printed maxillary first molars incorporating Vertucci Type II and IV configurations. Participants were assigned to naked-eye (NE), dental loupe (DL; 3.5×), or dental operating microscope (DOM) visualization. Access cavity preparation and MB2 canal scouting times were recorded, and MB2 detection was confirmed by insertion of a size-10 K-file. Use of ultrasonic tips and long-shank burs was documented. Statistical analyses included two-way ANOVA for procedural time comparisons, chi-square or Fisher’s exact tests for categorical variables, and logistic regression to evaluate factors associated with MB2 detection (α = 0.05). Results: The overall MB2 detection rate was 49.2%. Detection varied by magnification modality, with rates of 25.0% for naked-eye visualization, 45.0% for dental loupes, and 70.0% for the dental operating microscope. In multivariable analysis using a parsimonious model, DOM use was associated with higher odds of MB2 detection; however, the confidence interval included unity, indicating a borderline association. MB2 detection rates were similar between endodontists and residents (50.0% vs. 47.6%), with no statistically significant difference between groups. Ultrasonic tip use was associated with a higher frequency of scouting-related perforations but did not improve detection. Operators who successfully detected MB2 completed scouting in significantly less time. Conclusions: Under controlled, anatomically standardized laboratory conditions, visual magnification, particularly use of the dental operating microscope, was associated with greater efficiency of MB2 canal detection and shorter scouting times, beyond non-significant trends related to operator experience. Although 3D-printed models do not fully replicate the mechanical and tactile properties of natural dentin, their reproducible anatomy allows reliable assessment of operator- and device-related factors in a controlled setting. Given the simulated environment and the presence of borderline statistical associations, these findings should be interpreted cautiously and should not be directly extrapolated to clinical outcomes without further validation in clinical studies. Full article

Background and Objectives: Dentigerous cysts are benign odontogenic lesions associated with the crowns of impacted teeth and are the second most common odontogenic cyst after radicular cysts. Despite being described as slow-growing, their growth has not been numerically quantified. This study aims to determine the radiological growth rate of dentigerous cysts through quantitative analysis, to clarify their biological behavior, improve clinical management, and guide future research by filling a significant gap in the literature. Materials and Methods: In this retrospective study, records of 187 patients diagnosed with dentigerous cysts at Dicle University between 2020 and 2024 were reviewed. Twelve patients with cysts associated with mandibular impacted third molars and at least two high-quality panoramic radiographs taken at different time points were included. In all of these patients with adequate and suitable radiographic records, the dentigerous cysts were associated with mandibular third molars, which contributed to the standardization of imaging and measurements. All images were obtained using the same digital system and converted to DICOM format. Maximum anteroposterior (A–P) and inferosuperior (I–S) dimensions were measured twice by the same examiner, and mean values were recorded. Follow-up intervals were noted, and monthly dimensional changes were evaluated. Due to the rarity of untreated cases, a sample of only 12 patients was considered meaningful. Results: Most patients were female, with no significant gender differences in age or follow-up time. Cyst dimensions increased over time, showing marked enlargement in the anteroposterior (A–P) direction and a similar upward trend in the inferosuperior (I–S) dimension. Conclusions: In our study, growth in the anteroposterior direction was higher than that in the inferosuperior direction, and no significant differences in growth rates were observed with respect to sex or age. Full article

Background: This study aimed to investigate the dimensional deformation that can occur during the fabrication of a 3D-printed aligner made with the TC-85 DAC resin (Graphy Inc., Seoul, Republic of Korea) and determine if the manual removal of the print supports before final aligner curing affects the dimensional accuracy. Methods: 10 subjects with permanent dentition were selected, and a set of aligners was digitally designed using the uDesign Direct Aligner beta software (Graphy Inc., Seoul, Republic of Korea). Each aligner was 3D-printed using TC-85 DAC resin (Graphy Inc., Seoul, Republic of Korea) twice: one copy was produced removing the print supports before final curing, whereas the other was cured with the supports still attached. The aligners were digitized and compared to the original design of the digitally designed aligner using RMS and Inter-second molar distance data to identify variations between 3D-produced aligners and their respective digital design. Results: the comparison between aligners produced in two different ways was statistically significant with a p-value < 0.0001 for both the records used. Conclusions: the manual removal of the print supports before final curing affects the dimensional accuracy of aligners made by direct 3D printing, permanently altering the aligner’s internal geometry, confirming that post-processing conditions significantly affect dimensional stability. Full article

Fly ash-based geopolymer concrete (FAGC) is a sustainable alternative to Portland cement concrete, offering significant reductions in carbon emissions while maintaining sufficient strength. This study proposes a three-stage framework for developing empirical formulae to accurately and interpretably predict FAGC compressive strength. In the first stage, predictive models were developed using linear regression (LR), deep neural network (DNN), and residual neural network (ResNet) approaches. Among these, the ResNet model achieved the highest predictive accuracy and effectively captured the complex nonlinear relationship between mix components, curing conditions, and compressive strength. In the second stage, global sensitivity analysis identified sodium silicate content, curing time, sodium hydroxide molarity, and water content as the most influential variables. Additionally, the interaction between fine aggregate content and curing temperature was found to have a substantial effect on strength development. In the final stage, an empirical formula was developed based on key variables and their interactions, providing a simple yet reliable tool for practical strength prediction with reduced computational requirements. The proposed framework is expected to bridge the gap between machine-learning prediction and applicability to support mix design optimisation and promote the wider adoption of sustainable geopolymer concrete in construction applications. Full article

Pb (II) contamination in wastewater represents a grave threat to the environment and ecosystems. Consequently, there is an urgent need to prepare low-cost and highly efficient Pb (II) adsorbents. To address this need, abundant and low-cost natural silica-based desert sand (DS) was innovatively utilized as a carrier to develop efficient and selective Pb (II) adsorbents. Modified desert sand (MDS) was first prepared via 1 M HCl pretreatment for 2 h and subsequent KH550 silane modification. Pb (II)-imprinted composites (Pb (II)-IIP@MDS) were then fabricated via ion-imprinted polymerization, using Pb (II) as the template ion and N-hydroxymethacrylamide (NHMA)/hydroxyethyl methacrylate (HEMA) as dual functional monomers with a molar ratio of 1:1. The synthesized Pb (II)-IIP@MDS was comprehensively characterized by X-ray photoelectron spectrometer (XPS), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). The adsorption capacity, selectivity, and reusability of this material for lead ions were evaluated through three experiments conducted within the optimized pH range of 6–7, with error bars indicated. In adsorption isotherm experiments, the initial Pb (II) concentration ranged from 50 to 500 mg·L⁻¹, conforming to the Langmuir model (R² = 0.992), with a theoretical maximum adsorption capacity reaching 107.44 mg·g⁻¹; this indicates that the adsorbate forms a monolayer adsorption on the homogeneous imprinted sites. Kinetics data indicate that the process best fits a quasi-first-order kinetic model (R² ≥ 0.988), while the favorable quasi-second-order kinetic fit (R² ≥ 0.982) reflects the synergistic effect of physical diffusion and ion-imprinting chemistry, reaching equilibrium within 120 min. Thermodynamic parameters (ΔH⁰ = 12.51 kJ·mol⁻¹, ΔS⁰ = 101.19 J·mol⁻¹·K⁻¹, ΔG⁰ < 0) confirmed endothermic, entropy-increasing, spontaneous adsorption. In multicomponent systems, Pb (II)-IIP@MDS showed distinct Pb (II) selectivity. It retained 80.3% adsorption efficiency after eight cycles. This work provides a promising strategy for fabricating low-cost, high-performance Pb (II) adsorbents, and Pb (II)-IIP@MDS stands as a practical candidate for the remediation of Pb (II)-contaminated wastewater. Full article

The synthesis of two novel materials, aluminum-based MOF (Al-MOF) and cellulose-modified MOF (Al-MOF@C), as adsorbents is presented. Al-MOF was synthesized from aluminum sec-butoxide and terephthalic acid in a 1:1 molar ratio using a solvothermal method. Al-MOF@C was synthesized under similar solvothermal conditions by reacting environmentally friendly starting materials such as aluminum sec-butoxide, terephthalic acid, and cellulose in a 1:1:1 molar ratio. The synthesized materials’ structural, morphological, and surface properties were thoroughly characterized using XRD, SEM, EDS, BET (with specific surface areas calculated as 563.9 m²/g for Al-MOF and 487.1 m²/g for Al-MOF@C), and FTIR analyses. Then they were utilized in the water treatment process to remove the highly toxic anionic Congo red (CR) dye. Dye adsorption studies were carried out using UV-Vis spectroscopy. Batch adsorption experiments showed that Al-MOF and Al-MOF@C materials adsorbed CR dye with removal efficiencies of 95.06% and 91.79% in just 4 min, respectively. The equilibrium adsorption isotherm data for Al-MOF and Al-MOF@C were best fitted by the Langmuir model, and the calculated maximum adsorption capacities were 80.64 mg/g and 68.96 mg/g, respectively. The adsorption kinetics exhibited an excellent correlation with the pseudo-second-order model (R² = 0.9975 for Al-MOF and R² = 0.9936 for Al-MOF@C). Measurements taken after the adsorption process showed that Al-MOFs synthesized using environmentally friendly chemicals retained their stable chemical structure in aqueous environments and thus did not create secondary pollution in the environment, highlighting the importance of this study. Chemically stable, thermodynamically favorable, and highly reusable Al-MOF adsorbents offer a promising solution for the advanced environmental remediation of hazardous dye contaminants. Full article

Molar incisor hypomineralisation (MIH) is a developmental defect affecting permanent first molars and often the incisors too. Hypomineralised second primary molars (HSPM) have been proposed as potential early indicators of MIH. Aim: The aim was to identify potential aetiological factors associated with MIH and assess their relationship with HSPM in a pilot study. Methods: A cross-sectional case–control study was conducted with 120 patients (60 cases and 60 controls), aged 7–15 years, from the Paediatric Dentistry Postgraduate Programme. MIH was diagnosed following European Academy of Paediatric Dentistry (EAPD) guidelines. Parents completed a structured questionnaire on potential aetiological factors. Results: MIH was significantly associated with maternal smoking during pregnancy (p = 0.013), birth hypoxia (p = 0.013) and the use of amoxicillin and inhalation therapy during infancy (p < 0.001). It was also associated with tonsillitis (p = 0.022), bronchiolitis (p = 0.005) and other respiratory disorders (p = 0.049). HSPM was associated with anaemia and hypotension during pregnancy (p = 0.001), bottle-feeding (p = 0.044) and urinary tract infections (p = 0.003). No statistically significant association was found between MIH and HSPM. Conclusions: This pilot study has identified specific prenatal, perinatal, and postnatal factors associated with MIH and HSPM. The findings emphasise the clinical relevance for early diagnosis and management and highlight the need for studies with larger sample sizes to validate these associations. Full article

Ceftobiprole is a novel and promising antibiotic; however, the direct pharmacological use of its native form is limited by its low water solubility. The first part of this study provides a deeper insight into the physicochemical properties of this drug. One- and two-dimensional nuclear magnetic resonance (NMR) spectra in D₂O were recorded, and a complete assignment of ¹H and ¹³C signals was achieved with the support of quantum mechanical calculations. The combined results from capillary electrophoresis and NMR confirmed the cationic nature of ceftobiprole at pH values well below 3 and the protonation of the secondary amino group, thus supporting the theoretically predicted dominant protonation states. Molecular dynamics simulations revealed that zwitterionic ceftobiprole molecules associate through hydrogen bonding, whereas in the cationic form, the attractive forces involve weaker π-π and stacking interactions. The use of ceftobiprole in its native form in pharmaceutical formulations was made possible through the development of a novel freeze-dried cyclodextrin-based delivery system. Consequently, the second part of this article focuses on evaluating the biological properties of this system (ceftobiprole/maleic acid/sulfobutylether-β-cyclodextrin in a molar ratio of 1:25:4), including its antibacterial activity against the most common pneumonia-causing pathogens and its cytotoxicity towards normal and cancer cells. Full article

Background: This study examined the trends in restorative dental practice among 12-year-old children treated at a nationwide public health maintenance organization in Israel between 2016 and 2022, focusing on the use of amalgam versus composite resin restorations in permanent premolars and molars. Methods: Data were extracted from electronic health records of the second-largest public health organization in Israel, identifying children who underwent restorative treatments during the study period. Restoration rates were compared overall and stratified by gender, socioeconomic status, and number of surfaces restored. Statistical analysis was conducted using SPSS version 27, employing Levene’s test for equality of variances and Welch’s one-way ANOVA. Results: The results showed a statistically significant decline in amalgam use (p < 0.05) alongside a marked increase in composite resin restorations (p < 0.05), consistent across genders and socioeconomic groups. Notably, composite resins were increasingly selected for complex, multi-surface restorations (p < 0.05). Conclusions: These findings highlight a substantial shift in paediatric restorative practice in Israel, reflecting growing preference for composite resins likely influenced by patient demands and national dental reforms that eliminated financial barriers. The observed trend underscores the importance of continued monitoring of material selection to guide evidence-based practice in pediatric dentistry. Full article