Search Results (367)

Primary teeth play a crucial role in a child’s development, particularly in maintaining space for permanent teeth. The premature loss of a primary tooth can lead to orthodontic issues, making the use of space maintainers essential to ensure proper growth and development of permanent teeth. To preserve space, the fabrication of a space maintainer is necessary. Since conventional space maintainers do not restore masticatory function, this study presents an innovative solution for space preservation following the extraction of the first primary molar through the design of the functional space maintainer KOS&MET (Key Orthodontic System and Materials Enhanced Therapy). The space maintainer was designed using the 3Shape Dental Designer 2023 version software tool and manufactured via additive 3D printing, utilizing a metal alloy with high resistance to masticatory forces. The crown is supported by the primary canine, while an intraoral window is created to monitor the eruption of the successor tooth. This design does not interfere with occlusion and enables bilateral chewing. Masticatory performance was assessed using two-color chewing gum, and the results showed improvement after cementing the space maintainer. This innovative approach not only preserves space for permanent teeth but also enhances masticatory function, contributing to the proper growth and development of the jaws and teeth. Full article

Background: Osteodysplastic syndromes comprise a very diverse group of clinically and genetically heterogeneous disorders characterized by defects in bone and connective tissue development, as well as in bone density. Here, we report the case of a 48-year-old female with a complex medical history characterized by bone dysplasia, hyperostosis, and partial tooth agenesis. Methods: Genetic testing was performed using WES analysis and Sanger sequencing. Molecular modeling analysis and dynamics simulation explored the impact of detected pathogenic variants. Results: The genetic analysis detected multiple pathogenic variants in genes CREB3L1, SLCO2A1, SFRP4, LRP5, and LRP6, each of which has been associated with rare osteodysplastic syndromes. The patient was homozygous for the same rare alleles associated with three of the identified autosomal recessive disorders osteogenesis imperfecta type XVI, primary hypertrophic osteoarthropathy, and metaphyseal dysplasia Pyle type. She also had a variant linked to autosomal dominant endosteal hyperostosis and a variant previously associated with increased risk of osteoporosis and bone fractures. Two of the detected variants are predicted to cause abnormal splicing, while molecular modeling and dynamics simulations analysis suggest that the other three variants probably confer altered local secondary structure and flexibility that may have functionally devastating consequences. Conclusions: Our case highlights the rare coexistence of multiple osteodysplastic syndromes in a single patient that may complicate differential diagnosis. Furthermore, this case emphasizes the necessity for early genetic investigation of such complex cases with overlying phenotypic traits, followed by genetic counseling, facilitating orchestration of clinical interventions and allowing prevention and/or prompt management of manifestations. Full article

This study presents an analysis of the electromagnetic noise and vibration in a surface-mounted permanent magnet synchronous machine (SPMSM), focusing on their excitation sources. To investigate this, the excitation sources were identified through an analytical approach, and their effects on electromagnetic noise and vibration were evaluated using a finite element method (FEM)-based analysis approach. Additionally, an equivalent curved-beam model based on three-dimensional shell theory was applied to determine the deflection forces on the stator yoke, accounting for the tooth-modulation effect. The stator’s natural frequencies were derived through the characteristic equation in free vibration analysis. Modal analysis was performed to validate the analytically derived natural frequencies and to investigate stator deformation under the tooth-modulation effect across various vibration modes. Furthermore, noise, vibration, and harshness (NVH) analysis via FEM reveals that major harmonic components align closely with the natural frequencies, identifying them as primary sources of elevated vibrations. A comparative study between 8-pole–9-slot and 8-pole–12-slot SPMSMs highlights the impact of force variations on the stator teeth in relation to vibration and noise characteristics, with FEM verification. The proposed method provides a valuable tool for early-stage motor design, enabling the rapid identification of resonance operating points that may induce severe vibrations. This facilitates proactive mitigation strategies to enhance motor performance and reliability. Full article

Caragana korshinskii Kom. (CKB), widely cultivated in Inner Mongolia, China, has potential for silage feed development due to its favorable nutritional characteristics, including a crude protein content of 14.2% and a neutral detergent fiber content below 55%. However, its vascular bundle fiber structure limits the efficiency of lactic acid conversion and negatively impacts silage quality, which can be improved through mechanical crushing. Currently, conventional crushing equipment generally suffers from uneven particle size distribution, high energy consumption, and low processing efficiency. In this study, a layered aggregate model was constructed using the discrete element method (DEM), and the Hertz–Mindlin with Bonding contact model was employed to characterize the heterogeneous mechanical properties between the epidermis and the core. Model accuracy was enhanced through reverse engineering and a multi-particle-size filling strategy. Key parameters were optimized via a Box–Behnken experimental design, with a core normal stiffness of 7.37 × 10¹¹ N·m⁻¹, a core shear stiffness of 9.46 × 10¹⁰ N·m⁻¹, a core shear stress of 2.52 × 10⁸ Pa, and a skin normal stiffness of 4.01 × 10⁹ N·m⁻¹. The simulated values for bending, tensile, and compressive failure forces had relative errors of less than 10% compared to experimental results. The results showed that rectangular hammers, due to their larger contact area and more uniform stress distribution, reduced the number of residual bonded contacts by 28.9% and 26.5% compared to stepped and blade-type hammers, respectively. Optimized rotational speed improved dynamic crushing efficiency by 41.3%. The material exhibited spatial heterogeneity, with the mass proportion in the tooth plate impact area reaching 43.91%, which was 23.01% higher than that in the primary hammer crushing area. The relative error between the simulation and bench test results for the crushing rate was 6.18%, and the spatial distribution consistency reached 93.6%, verifying the reliability of the DEM parameter calibration method. This study provides a theoretical basis for the structural optimization of crushing equipment, suppression of circulation layer effects, and the realization of low-energy, high-efficiency processing. Full article

Background and Objectives: Periodontitis is an inflammatory disease that compromises the supporting structures of the teeth, leading to irreversible tissue damage and tooth loss. While subgingival professional mechanical plaque removal (PMPR) remains the gold standard treatment, there is increasing interest in adjunctive therapies. Platelet-rich fibrin (PRF) has gained attention as a promising biomaterial to enhance periodontal healing and regeneration. This study aimed to evaluate the clinical and immunological effectiveness of PRF as an adjunct to PMPR. Materials and Methods: Clinical studies published between January 2019 and August 2024 were included from the ProQuest, PubMed, PMC, ScienceDirect, Scopus, and EBSCO databases. Seven studies met the inclusion criteria, focusing on adults with periodontitis treated with PRF + PMPR compared to PMPR alone. Primary outcomes included changes in clinical and immunological parameters. Risk of bias was assessed using the Cochrane ROB2 tool. Meta-analysis was conducted using both fixed-effect and random-effects models, depending on heterogeneity. Results: The meta-analysis demonstrated significant improvements in clinical outcomes in the PRF + PMPR group, with reductions in probing pocket depth (SMD: −1.43 mm; 95% CI: −2.05 to −0.81; p < 0.00001), clinical attachment level (SMD: −1.34 mm; 95% CI: −1.95 to −0.73; p < 0.0001), bleeding on probing (SMD: −0.75 mm; 95% CI: −1.11 to −0.39; p < 0.00001), gingival recession (SMD: −0.79 mm; 95% CI: −1.33 to −0.25; p = 0.004), and gingival index (SMD: −0.82 mm; 95% CI: −1.37 to −0.28; p = 0.003). Favorable trends were also observed in IL-10, TGF-β, VEGF, PDGF-BB, periostin, and type I collagen levels. Conclusions: PRF enhances clinical and immunological outcomes and supports periodontal tissue stability when used as an adjunct to non-surgical therapy. Full article

Vitiligo, an autoimmune disorder causing depigmented skin patches, includes two types, segmental (SV) and non-segmental (NSV). Previously, NSV was off-label treated using Calcineurine inhibitors (Tacrolimus and Pimecrolimus). In 2022, the FDA approved Ruxolitinib cream, targeting the JAK/STAT pathway for NSV treatment based on promising results. This research conducts a retrospective descriptive safety assessment of Tacrolimus, Pimecrolimus, and Ruxolitinib safety in vitiligo treatment, utilizing the FDA Adverse Event Reporting System (FAERS) database spanning the period from 2013 to 2023 and including patients aged 2 years and above, encompassing both brand and generic names. A total of 844 adverse event reports involving 388 patients were extracted and categorized into dermatological and systemic groups for analysis. Tacrolimus resulted in 12 hospitalizations, two life-threatening events, and four disabilities. Pimecrolimus exhibited urticaria and pigmentation disorders, with tooth fracture as the primary systemic event. Pericarditis was the predominant systemic side effect of Ruxolitinib, followed by anemia, headache, and urosepsis. Local dermatological side effects reported were generally mild, not warranting treatment cessation. In conclusion, vitiligo significantly impacts patients’ psychological well-being, necessitating continuous post-marketing safety monitoring for topical medications. Full article

Background: In modern dentistry, alveolar socket preservation after tooth extraction plays a critical role in maintaining the alveolar ridge for future dental implants. This retrospective clinical study evaluated bone-level changes 15 years after immediate implant placement, coupled with alveolar ridge preservation. Methods: Fifty non-smoking patients aged 25 to 75 (30 males and 20 females) who underwent single-implant rehabilitation in both anterior and posterior regions of the upper and lower jaws were included. The study examined bone levels and implant survival over time, using standardized intraoral radiographs at 1, 5, and 15 years post-loading. Implants were placed immediately after atraumatic extraction, and the residual gap was grafted with bovine hydroxyapatite and covered with a collagen membrane. The primary outcome was bone-level stability, while secondary outcomes included implant failure. No temporary crowns or removable dentures were provided during healing. Radiographs were digitized for detailed analysis. Results: The results for 50 patients with immediate implant placement showed that bone-resorption levels were significantly higher in the upper jaw than in the lower jaw. Conclusions: Posterior implants exhibited greater bone loss than anterior implants, particularly at 1 year and 15 years, while no implant failures occurred. Full article

Background: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) represents a severe complication associated with bisphosphonate therapy commonly used in patients with osteoporosis and malignancies. Methods: This retrospective study evaluates the risk factors and clinical outcomes of BRONJ patients treated at the Oral and Maxillofacial Surgery Clinic in Iaşi, Romania, with the goal of optimizing preventive and therapeutic strategies. Data from 72 BRONJ patients treated between January 2013 and December 2023 were analyzed. Results: The majority (83.3%) of patients had underlying malignancies, predominantly breast and prostate cancers. The mandible was most affected, with tooth extraction identified as the primary triggering event. Systemic comorbidities, notably arterial hypertension, diabetes mellitus, and concurrent chemotherapy, were significantly associated with increased BRONJ severity. Surgical intervention was frequently required, with sequestrectomy being the predominant procedure, reflecting advanced disease at the time of diagnosis. Conclusions: The findings underline the critical importance of early identification, preventive dental management, and a collaborative multidisciplinary approach to improve patient prognosis. Full article

Background: Early childhood dental decay remains a pervasive chronic condition, and environmental toxicants—particularly lead—may exacerbate its development. This systematic review was designed to synthesize evidence on how lead exposure correlates with both the occurrence of carious lesions and aesthetic alterations in children’s primary teeth. Methods: A comprehensive search was conducted in PubMed, Scopus, and Web of Science through April 2025, selecting observational investigations that assessed the link between lead levels and primary-tooth decay in pediatric cohorts. Thirteen eligible studies, encompassing 44,846 participants aged 2–19 years, were included for qualitative synthesis. Aesthetics were screened using author-defined enamel-defect or discoloration endpoints; however, only three studies reported compatible metrics, precluding quantitative pooling. Heterogeneity in exposure matrices likewise ruled out meta-analysis. Results: Most studies reported a statistically significant association between higher lead burden and greater prevalence or severity of caries in primary teeth. Blood lead concentrations across studies ranged from means of 1.53 μg/dL to geometric means of 7.2 μg/dL. Notably, elevated lead was linked to increased decayed, missing, or filled surfaces—with an adjusted risk ratio of 1.14 (95% CI: 1.02–1.27) at levels below 5 μg/dL—and adjusted mean ratios of up to 2.14 for decayed or filled teeth when blood lead reached 5–10 μg/dL. Conclusions: Current evidence suggests that children’s exposure to lead may heighten the risk of caries and detract from the aesthetic quality of primary teeth. However, variability in study design, lead quantification methods, and confounder adjustment limit the consistency of findings. Mitigating lead exposure in early life could represent a valuable preventive strategy against dental decay in susceptible pediatric populations. Full article

Background: The dentin–pulp complex plays a vital role in tooth health. Dentin forms the main body the tooth and continues to form throughout life to maintain homeostasis and provide protection against deleterious external stimuli. However, the detailed mechanism of dentin formation remains poorly understood, and there is a need for new regenerative therapies. This study therefore investigated whether primary dental pulp cells from mice could be used to establish a new culture system. Methods: Mouse mandibles were divided along the ramus to extract dental pulp tissue containing cervical loops. The extracted tissue was cultured in an incubator to promote cell out-growth and increase the number of cells available for experimentation. Results: Cultured cells formed mineralized nodules, confirmed by Alizarin red S staining. The expression levels of dentin sialo protein, bone gamma-carboxyglutamate protein, and type I collagen mRNAs in cultured dental pulp cells on day 15 were lower than those in intact mouse dental pulp tissue, and the expression of all mRNAs was confirmed through electrophoresis. Conclusions: This study established a primary culture system using dental pulp tissue extracted from mouse mandibular incisors. The results demonstrated that dental pulp cells can differentiate into odontoblast-like cells and form dentin-like mineralized nodules, thereby offering a useful system for studying dentin formation and odontoblast differentiation. Full article

Objectives: This meta-analysis aims to estimate the pooled prevalence of dental caries among children in Turkey by synthesizing national evidence from theses and peer-reviewed articles published between 2000 and 2024. Methods: Studies were retrieved from the YÖK Thesis Database and Google Scholar using keywords such as ‘Caries Prevalence’ and ‘Primary Tooth.’ PubMed was used to cross-check peer-reviewed articles. A total of 28 studies and 29 data points including 40,244 children aged approximately 2 to 15 years were included. PRISMA guidelines were followed. Heterogeneity was assessed using the I² index, and publication bias was evaluated with an Egger’s test and funnel plots. Results: The pooled prevalence of dental caries among Turkish children was 75.6% (95% CI: 70.8–79.8%). Substantial heterogeneity was observed (I² = 98.4%), but no significant publication bias was detected. Conclusions: Dental caries remains a significant public health issue among children in Turkey. Targeted preventive measures—such as nationwide dental screenings and school-based fluoride programs—are urgently needed. Full article

Background/Objectives: Dental caries (DCs) and type 2 diabetes share common risk factors. Dental caries risk in type 2 diabetics (T2DM) shows contradictory results. The aim of this study was to determine if there is a difference in DC prevalence in adults with and without T2DM and whether body mass index (BMI) classes or glycated hemoglobin (HbA1c) levels interfere in that difference. Methods: A total of 666 adults (n(T2DM) = 343; n(nT2DM) = 323), from Espinho Primary Health Care Center, were interviewed by calibrated observers. Data from clinical records were collected and oral health status was registered using WHO criteria. Inference analysis was conducted using non-parametric tests (α = 0.05). Results: A similar caries prevalence was found between the T2DM (98.2%) and nT2DM (98.8%) groups, with the T2DM group showing significantly higher tooth loss (p < 0.001), higher caries experience rerted as mean ± sd (17.7 ± 8.3 vs. 15.9 ± 7.8, p = 0.005), fewer decayed teeth (p < 0.001) and filled teeth (p = 0.016) compared to nT2DM. The most frequently identified comorbidity was hypertension (53.6%). Tobacco use (12.9%) was lower in T2DM (p < 0.001). The restorative and treatment indices indicated a significantly higher proportion of use of oral care services (p < 0.001) in T2DM individuals. The prevalence of the higher classes of BMI indicative of pre-obesity or obesity shows significant differences (p < 0.001). The differences found in the DMFT or each of its components for the prevalence or for the mean in HbA1c control were not statistically significant (p = 0.368, and 0.524, respectively). Conclusions: Adults with T2DM and higher BMI classes could be associated with a greater prevalence of DCs. The glycemic control of T2DM does not significantly influence DMFT score or each of its components. Full article

The Dujiangyan–Siguniangshan mountain rack railway project is China’s first mountain rail transit. Most of its lines are located in mountainous areas and close to natural ecological protection areas, which have strict restrictions on the vibration and noise of train operation. At the same time, the vibration of mountain rack railway trains is also an important factor affecting the safety and riding comfort of trains. However, due to the multi-source vibration of gear teeth, wheels, rails, and suspensions, it is difficult to clearly define the vibration characteristics and vibration transmission path of the train, which has a serious impact on its vibration noise suppression and optimization. To this end, this study proposed a set of evaluation methods for the vibration characteristics and transfer paths of mountain rack trains based on a combination of dynamics and operational transfer path analysis (OTPA). Considering the interaction between the dynamic behaviors of the primary and secondary suspensions, the gear tooth contact behavior, the wheel–rail contact behavior and the dynamic behaviors of the track system, a dynamic model of a mountain rack train based on the finite element method was established, and the effectiveness of the model was verified through field experiments. On this basis, the OTPA method was used to establish a vibration transfer path model between the secondary suspension and the center of mass of the car body, and it was used to analyze the vibration mechanism and transfer path of the train body at the rated speed (20 km/h) and the limited speed (30 km/h). This study is of great significance for suppressing the vibration noise of mountain rack trains, reducing the impact on the ecological environment and improving ride comfort. Full article

Background/Objectives: Coronectomy is an alternative to complete third molar extraction to reduce the risk of inferior alveolar nerve injury. This systematic review of systematic reviews evaluates re-intervention rate, timing, and indications after mandibular third molar coronectomy. Methods: A systematic search following PRISMA guidelines was conducted across Scopus, MEDLINE/PubMed, BioMed Central, Web of Science, Cochrane Library and PROSPERO. Studies reporting re-intervention rates after at least six months from coronectomy were included. Data extraction focused on re-intervention timing, indications, and complications. Results: Six systematic reviews, including 5896 subjects and 7913 successful coronectomies (not requiring immediate tooth extractions), were analyzed. The overall re-intervention rate was 4.45%, with timing ranging from six months to ten years (mean: 10.4 months). Root exposure (16.76%) was the primary cause, followed by infection (4.55%) and pain (2.84%). Root migration (12.20%) was common, while inferior alveolar nerve injury remained rare (0.76%). Conclusions: Coronectomy is a viable alternative in high-risk cases, with a low re-intervention rate. Root migration and exposure require long-term follow-up. Standardized imaging protocols and refined re-intervention criteria are needed. Full article

Background: The Hall Technique (HT) in pediatric dentistry is a minimally invasive method for treating carious primary molars by sealing cavities with preformed stainless-steel crowns, eliminating the need for local anesthesia, caries removal or tooth preparation. Objectives: To assess the knowledge, attitude, and teaching of HT among pediatric dentistry faculty in Riyadh, Saudi Arabia. Methods: A cross-sectional descriptive study involved 36 pediatric dentistry faculty members from six dental colleges in Riyadh. Data were collected using a validated questionnaire covering demographics and professional information, HT knowledge, attitude, and teaching strategies. Results: Thirty-one pediatric dentistry faculty responded to the questionnaire, and 67.74% of participants use HT clinically, primarily for asymptomatic carious primary molars. Most participants learned about HT during postgraduate residency (61.29%), while only 6.45% were introduced to it in undergraduate training. Teaching practices varied, with 51.61% teaching HT to undergraduate and/or postgraduate students, and 16.13% omitting it from their curriculum. Key barriers to HT adoption included limited undergraduate exposure, misconceptions, and a lack of standardized guidelines. Fisher’s Exact Test showed that gender, academic position, and years of experience were significantly associated with HT use. Only years of experience were significantly associated with recommending HT use by undergraduate students. No factors were significantly associated with teaching HT. Conclusions: While awareness of HT is high among pediatric dentistry faculty, inconsistent teaching and limited clinical use hinder its full integration. Addressing these barriers through curriculum updates and professional development could enhance the acceptance and quality of HT use in pediatric dentistry in Saudi Arabia. Full article