Explore the vast range of titles available.

Objective Migrants living in Germany constitute a large and heterogeneous population that is exposed to socioeconomic disadvantages, language barriers and difficulties navigating the health system, all of which may negatively affect oral health and access to dental care. The aim of this study was to systematically review and synthesize available evidence on differences in oral health status and dental service utilization between migrant and non-migrant populations in Germany. Methods A systematic review of peer-reviewed observational and clinical studies conducted in Germany was performed. Studies meeting predefined inclusion criteria were selected, focusing on oral health indicators such as dental caries prevalence (DMFT scores), periodontal health, and access to preventive dental care. Data on study characteristics, population demographics and outcomes were extracted using a standardized form. Where at least three sufficiently homogeneous studies were available, a meta-analysis of DMFT outcomes was conducted. Results Seventeen studies were included in the qualitative synthesis and three in the meta-analysis. Across adult populations, migrants consistently showed worse oral health than non-migrants, with higher DMFT scores (SMD = 0.40; 95% CI: 0.31–0.49; p  < 0.05) scores than non-migrants, driven primarily by a higher number of missing teeth (M) (SMD = 0.17; 95% CI: 0.08–0.26; p  < 0.05), while differences in decayed (D) and filled (F) teeth were smaller and more heterogeneous. Children and adolescents with a migration background, particularly those living in socioeconomically disadvantaged areas, had higher caries experience and a lower probability of caries-free dentitions in permanent teeth. Evidence on caries in primary dentition (dmft) was limited and heterogeneous and therefore summarized qualitatively only. Across age groups, migrants had lower odds of attending regular preventive dental check-ups than non-migrants (OR approximately 0.64–0.67). Discussion Despite statutory health insurance in Germany, migrants struggle with access to dental services. Structural and social determinants, including socioeconomic position, health literacy, language barriers, and perceived discrimination, likely contribute to these disparities. Conclusion Targeted public health strategies, culturally and linguistically adapted information, and measures to improve accessibility of dental care are needed to reduce oral health inequalities between migrants and the native German population.

3D printing is increasingly utilized in dentistry. Compared to traditional manufacturing methods, 3D printing provides advantages such as faster production times and the ability to create complex structures. Although biocompatible materials are available, many are only suitable for temporary applications. This study examines the impact of nitrogen-aided post-processing on the mechanical properties and cytotoxicity of 3D-printed denture bases, with the hypothesis that this post-processing will enhance material properties and decrease cytotoxicity. Specimens were fabricated from V-print dentbase (Voco GmbH, Cuxhaven, Germany) and post-processed either in nitrogen or air. The specimens were categorized into aged and non-aged groups. For comparison, specimens made from milled material were utilized. Vickers hardness, flexural strength, polishability, cytotoxicity, and degree of conversion were then assessed for all groups. The data were analyzed using a one-way ANOVA and Tukey HSD test for multiple comparisons, with a significance threshold of p  < 0.05. Post-curing with nitrogen improved the degree of conversion, surface hardness, and biocompatibility of 3D-printed dental materials, confirming reduced cytotoxicity without impairing mechanical properties. Nitrogen increased polymerization and decreased harmful monomers, making it ideal for clinical applications in contact with the oral mucosa. Optimizing post-processing steps, such as curing in nitrogen, enhances biocompatibility while maintaining strength and hardness, ensuring better patient care in dental applications.

The rapid advancement of three-dimensional (3D) printing in dentistry has prompted comparisons between the mechanical properties of polylactic acid (PLA) samples fabricated using material extrusion (MEx) and resin samples produced using digital light processing (DLP). This study aims to assess the potential of replacing resin-based models with PLA models in clinical settings by evaluating the mechanical properties and accuracy of MEx-printed PLA and DLP-printed resin samples. The investigated materials include pure PLA, a PLA composite containing gypsum, and a clinically approved resin material. Strength and hardness tests were conducted using custom-made samples measuring 16 × 4 × 2 mm 3 . Additionally, oral cavity scans were used to generate oral models for each material to assess their accuracy, trueness, and precision. The results indicated that pure PLA exhibited the highest flexural modulus (2055 ± 217.70 MPa) and compression modulus (2.40 ± 0.14 GPa). The PLA-Gypsum composite displayed the highest hardness (19.48 ± 2.12 HV1). As for the trueness of the oral models, there were no statistically significant differences between the models made from the three materials. However, the PLA-Gypsum composite demonstrated the best precision (23.84 ± 4.12 μm). These findings suggest that both PLA materials have significant potential to replace DLP-produced resin models in the clinical applications. Graphical Abstract

(1) Purpose: To compare the fabrication accuracy, internal fit, and marginal adaptation of three-unit definitive resin fixed dental prostheses (FDPs) produced by subtractive milling and additive manufacturing. (2) Materials and Methods: A typodont mandible was prepared for a three-unit FDP, with full crown preparations on teeth mandibular left canine and mandibular left second premolar featuring 1 mm chamfer finish lines. The FDP was designed with a 16 mm2 connector and a 100 µm cement gap. Two milling materials (Ambarino High-Class, IPS e.max CAD) and two experimental 3D printing hybrid resins (3D-1, 3D-2) were used. All restorations were scanned using an intraoral scanner and compared to the original STL using reverse engineering software for surface trueness and deviation analysis. The internal fit was evaluated using the triple-scan method, while marginal fit was assessed via micro-CT imaging. Statistical analysis was conducted using one-way ANOVA and Kruskal–Wallis tests (α = 0.05). (3) Results: Milled groups demonstrated a lower prevalence of external, marginal, and overall surface deviations (p < 0.001), while 3D-1 exhibited comparable deviations within the internal region with M-E (p = 0.067). Milled groups had average gap values that were similar to 3D-1 (p > 0.08), but significantly lower than 3D-2 (p < 0.002). In marginal adaptation evaluated by micro-CT, the M-A and M-E groups provided significantly lower gaps, while the 3D-1 and 3D-2 groups exhibited wider marginal and axial gaps. (4) Conclusions: These results indicate that while milling remains a more reliable manufacturing method for achieving external and marginal precision, position 3D-1 is a compelling, chairside alternative to milling.

Objectives The aim of this study was to evaluate the bond strength of different computer‐aided design/computer‐aided manufacturing (CAD/CAM) hybrid materials for milling and 3D‐printing with and without thermocycling. Different repair protocols were tested. Materials and Methods Two milled and one experimental 3D‐printed hybrid material were tested with three repair systems (MO [universal primer and dental adhesive]; GC [Repair Kit]; Voco Cimara [Repair Kit]). A total of 180 specimens were prepared (n = 60 per material). Half underwent thermocycling (30,000 cycles, 5°C–55°C), while the others were stored in distilled water (37°C). Shear bond strength was determined using a universal testing machine. Fracture modes were analyzed microscopically, and selected samples were examined via scanning electron microscopy. Data were analyzed by three‐way ANOVA followed by Tukey's and Bonferroni post hoc tests (p < 0.05). Results The results of the present study showed that the choice of repair protocol and the tested material significantly influenced the shear bond strength. MO achieved the highest shear bond strength values among all tested materials before and after thermocycling. After thermocycling, only GC in combination with the experimental 3D‐printed material depicted an increase in shear bond strength (12.55 → 14.51 MPa). Regarding the tested milled materials, thermocycling reduced shear bond strength across all protocols. Conclusions Shear bond strength was significantly influenced by the type of CAD/CAM material and repair protocol used. Thermocycling reduced shear bond strength in milled materials, while the 3D‐printed material showed improved values with specific protocols. Clinicians should be aware that both the choice of CAD/CAM material and the repair protocol significantly affect bond strength.

Purpose This systematic review aimed to evaluate the incidence of microleakage events (IME) and to identify the potential factors influencing the sealing ability of the implant–abutment interface (IAI) under in vitro investigation. Material and methods An electronic search of MEDLINE (PubMed), EMBASE, and Web of Science databases, combined with a manual literature search was conducted up to September 2022. In vitro studies that reported the degree of microleakage at IAI under dynamic loading conditions were included. A meta-analysis was performed to calculate the mean values of the incidence of microleakage events. Subgroup analysis and meta-regression were conducted to further investigate the effect of different variables. Results 675 studies were identified following the search process and 17 in vitro studies were selected according to the eligibility criteria. The weighted mean incidence of microleakage events was 47% (95% confidence interval: [0.33, 0.60]), indicating that contamination was observed in nearly half of the samples. Concerning possible factors that may influence microleakage (e.g., loading condition, assessment method, implant–abutment connection design, types of abutment material, the use of sealing agents), loading condition ( p  = 0.016) was the only variable that significantly influenced IME in the meta-regression analysis. Conclusions The results demonstrated that dynamic loading significantly increases the potential of bacterial penetration at the implant–abutment junction. The results should be interpreted carefully due to the data heterogeneity and further well-conducted in vitro studies with homogeneous samples are needed to standardize the methodologies. Graphical Abstract

Objectives The purpose of this study is to evaluate the bond strength of different computer-aided design / computer-aided manufacturing (CAD/CAM) hybrid ceramic materials following different pretreatments. Methods A total of 306 CAD/CAM hybrid material specimens were manufactured, n  = 102 for each material (VarseoSmile Crown plus [VSCP] by 3D-printing; Vita Enamic [VE] and Grandio Blocs [GB] by milling). Each material was randomly divided into six groups regarding different pretreatment strategies: control, silane, sandblasting (50 μm aluminum oxide particles), sandblasting + silane, etching (9% hydrofluorics acid), etching + silane. Subsequently, surface roughness (Ra) values, surface free energy (SFE) were measured. Each specimen was bonded with a dual-cured adhesive composite. Half of the specimens were subjected to thermocycling (5000 cycles, 5–55 °C). The shear bond strength (SBS) test was performed. Data were analyzed by using a two-way analysis of variance, independent t-test, and Mann-Whitney-U-test (α = 0.05). Results Material type ( p  = 0.001), pretreatment strategy ( p  < 0.001), and the interaction ( p  < 0.001) all had significant effects on Ra value. However, only etching on VSCP and VE surface increased SFE value significantly. Regarding SBS value, no significant difference was found among the three materials ( p  = 0.937), while the pretreatment strategy significantly influenced SBS ( p  < 0.05). Etching on VSCP specimens showed the lowest mean value among all groups, while sandblasting and silane result in higher SBS for all test materials. Conclusions The bond strength of CAD/CAM hybrid ceramic materials for milling and 3D-printing was comparable. Sandblasting and silane coupling were suitable for both millable and printable materials, while hydrofluoric etching should not be recommended for CAD/CAM hybrid ceramic materials. Clinical relevance Since comparable evidence between 3D-printable and millable CAD/CAM dental hybrid materials is scarce, the present study gives clear guidance for pretreatment planning on different materials.

The study investigated the impact of aging on surface roughness, color stability, and biocompatibility of hybrid resin-ceramic materials. A total of 225 specimens were produced from three three-dimensional (3D)-printed (HarzLabs Dental Sand Pro (HL), BEGO VarseoSmile Crown plus (BV), Voco V-Print c&b temp (VV)) and one milled material (Voco Grandio Blocs (VG)). Specimens were grouped into untreated, polished, and glazed surfaces. 5000 thermal cycles simulated aging. Surface roughness and color stability were analyzed, and surface topography was observed using scanning electron microscopy (SEM). Biocompatibility was evaluated with L929 cells. Surface roughness differed significantly between untreated and other groups, with no changes before and after artificial aging. Untreated milled samples were significantly smoother than 3D-printed ones. SEM analysis revealed roughest surfaces in untreated 3D-printed specimens. Polished and glazed specimens were smoother than untreated ones. Color values showed significant differences between untreated and treated/aged groups. No material showed cytotoxicity. In summary, untreated VG was smoother than 3D-printed materials, but polishing and glazing reduced roughness to levels comparable to VG. Surface treatments induced color changes, with glazing causing more changes than polishing. Aging affected color stability and biocompatibility but not surface roughness. All materials showed acceptable color changes and good biocompatibility.

The aim of this study was to compare the potential of standard ion-releasing materials to repair demineralized lesions with recently introduced alkasite and glass hybrid materials. Glass ionomer (GC Fuji TRIAGE), two glass hybrids (EQUIA Forte HT, Riva SC), calcium silicate cement (Biodentine) and an alkasite (Cention Forte) were tested. A total of 72 human third molars were used for sample preparation; on the dentine surface, a class-I cavity was prepared, and one half was covered with nail varnish. The teeth were subjected to a demineralization protocol, filled with the examined materials, and cut in half. The evaluation included a dentine microhardness assessment (n = 10) and SEM/EDS analysis (n = 2). The results were analyzed using SPSS 22.0 statistical software and compared using an analysis of variance and Scheffe post-hoc test. The statistical significance level was set to 0.05. Mean microhardness values (HV0.1) after 14 and 28 days were, respectively: EQUIA Forte HT (26.7 ± 1.45 and 37.74 ± 1.56), Riva Self Cure (19.66 ± 1.02 and 29.58 ± 1.18), Cention Forte (19.01 ± 1.24 and 27.93 ± 1.33), Biodentine (23.35 ± 1.23 and 29.92 ± 1.02), GC Fuji TRIAGE (25.94 ± 1.35 and 33.87 ± 5.57) and control group (15.57 ± 0.68 and 15.64 ± 0.82). The results were significantly different between most groups (p < 0.001). SEM/EDS revealed varying patterns, material deposits and distinct elemental variations. To conclude, all materials increased microhardness and affected the dentine surface appearance and chemical composition; EQUIA Forte HT demonstrated the most pronounced effects.

Root-analog implants are frequently fabricated from titanium, which can be associated with various problems, e.g. hypersensitivity to titanium. In this study, we evaluate the bending moments of different polyetheretherketone-based root analog implants as a metal-free alternative. For this, an extracted tooth 31 and 36 was scanned to create an STL data set of each tooth. These were used to fabricate n = 8 polyetheretherketone-based root analog implants per group, with 5 groups being fabricated per tooth type. Two groups were additively manufactured using material extrusion. The other groups were milled from differnet polyetheretherketone grades. After artificial ageing, the samples were statically loaded until fracture in order to determine the bending moment. Of the root analog implants in the form of a 31, a white, milled polyetheretherketone grade showed the highest bending moment of 2835.3 ± 509.8 Nmm and an unfilled, additively processed polyetheretherketone grade the lowest. Of the RAIs in the form of a 36, an unfilled, milled polyetheretherketone grade showed the highest bending moment with 29342.6 ± 854.7 Nmm and a white, additively processed polyetheretherketone grade showed the lowest bending moment with 19880.5 ± 7188.6 Nmm. Basically, the results between the additively and subtractively processed groups were significantly different. In terms of mechanical requirements in the oral cavity, one-piece milled polyetheretherketone −based RAIs appear to provide more predictable results than additively manufactured ones. Taken together, our study suggests that more solidly designed one-piece root analog implants made of milled polyetheretherketone in the form of molars appear to be able to withstand the mechanical requirements of the oral cavity.