Search Results (484)

This work presents the design, fabrication, and characterization of a three-dimensional FeCo-based flux-modulator microwinding intended for integration into high-torque axial-flux Vernier micromotors. The proposed micromotor architecture modulates the stator magnetic flux using 12 magnetically isolated FeCo teeth interacting with an 11-pole permanent-magnet rotor. The design requires the manufacturing of complex three-dimensional micrometric parts, including three teeth and a cylindrical core. Such a complex design cannot be manufactured using conventional micromanufacturing lithography or 2D planar methods. The flux-modulator envelope dimensions are 250 μm outer diameter and 355 μm height. It is manufactured using a femtosecond laser-machining process that preserves factory-finished surfaces and minimizes heat-affected zones. In addition, this micrometric part has been wound using 20 μm diameter enamelled copper wire. A dedicated magnetic clamping fixture is developed to enable multilayer microwinding of the integrated core, producing a 17-turn inductor with a 60.6% fill factor—the highest reported for a manually wound ferromagnetic-core microcoil of this scale. Geometric and magnetic characterization validates the simulation model and demonstrates the field distribution inside the isolated core. The results establish a viable micromanufacturing workflow for complex 3D FeCo microwindings, supporting the development of next-generation high-performance MEMS micromotors. Full article

Background/objective: To evaluate the effectiveness of resin infiltration in managing anterior molar incisor hypomineralization (MIH) defects, focusing on color improvement, lesion size reduction, sensitivity outcomes and patient aesthetic perception. Enamel defects in MIH result from a combination of environmental, systemic, and genetic factors, indicating a multifactorial etiology. These defects, particularly in anterior teeth, pose significant aesthetic and emotional challenges due to their high visibility. This study provides one of the few prospective clinical evaluations of resin infiltration for anterior MIH lesions, assessing not only objective clinical outcomes but also patients’ aesthetic perception. It further introduces a patient-centered approach by comparing aesthetic evaluations made by children and dental professionals over time. Methods: A total of 109 MIH-affected anterior teeth were treated using Icon^® resin infiltration (DMG, Hamburg, Germany) in this registered prospective clinical study (ClinicalTrials.gov: NCT05597956). Participants were classified as children (6–12 years) and adolescents (13–17 years) according to standard pediatric age definitions. Of these, 101 teeth were available for evaluation at the 6-month follow-up due to patient loss to follow-up. The evaluation included photographic follow-up, measurement of lesion size and color, and assessment of sensitivity. During follow-up visits, patients rated the appearance of their lesions using the FDI scale. Results: Before treatment, spectrophotometric analysis showed that lesions exhibited a reddish hue (mean a* = 2.12), were distinctly yellowish (mean b* = 23.20), and clearly differed from surrounding enamel (ΔE = 8.62). The brightness level (L* = 69.81) indicated medium-high luminosity. Lesion size was reduced by an average of 4.5 percentage points. Significant increases in L values and reductions in a* and b* components were observed, with clinically perceptible ΔE changes. Sensitivity improved in 36.6% of patients, who reported a 1–2 point decrease on the SCASS. Moreover, patients’ aesthetic perception significantly improved after Icon^® infiltration resin. Conclusions: Resin infiltration produced noticeable improvements in color, reduced lesion size and sensitivity, and enhanced aesthetic perception, making it a valuable treatment option for managing MIH-affected anterior teeth in children. Full article

In fixed orthodontic treatment, brackets are orthodontic attachments bonded to the tooth enamel, and their placement and removal may affect the underlying enamel surface. Enamel degradation is a critical factor for oral health, as it reduces the mechanical strength of teeth and increases susceptibility to caries and erosion. Accurate diagnosis of enamel changes is therefore essential for the evaluation of preventive and restorative treatments. In this study, enamel degradation was investigated via two integrated methods: energy-dispersive X-ray spectroscopy (EDS) and surface roughness measurement. The experimental protocol was performed in three stages: before bracket bonding, after bracket removal, and after applying a remineralization treatment. The experimental design included a repeated-measures structure, with stage (baseline, post-debonding, post-remineralization) as the within-tooth factor and bracket type (sapphire vs. metallic) as the between-tooth factor. Given the violation of the variance homogeneity assumption, group comparisons were ultimately performed using Welch ANOVA followed by Games–Howell post hoc tests, with Bonferroni-adjusted values used for pairwise comparisons. The presence of orthodontic brackets can influence enamel mineralization because the bonding and debonding procedures modify the enamel surface microtopography. These procedures can generate microcracks and surface irregularities, which may affect mineral exchange between enamel and the surrounding environment. In our study, bracket removal led to a significant decrease in the mean atomic percentages of Ca (from 32.65% to 16.37% for sapphire) and P (from 16.35% to 8.60% for sapphire), accompanied by a sharp increase in surface roughness. After remineralization, Ca and P levels increased, while roughness decreased. However, neither the mineral content nor the surface topography fully returned to the initial values, indicating that remineralization achieved only a partial recovery of enamel integrity. These findings highlight that the integrated EDS approach and roughness analysis offer a promising descriptive framework for assessing enamel degradation and monitoring the effectiveness of remineralization therapies. The generated mathematical model provides a powerful descriptive framework for the in vitro data obtained, correlating roughness with mineral composition and treatment stage. However, such a high goodness-of-fit (R² > 0.98) should be interpreted cautiously due to the risk of overfitting. Therefore, rigorous external validation is mandatory before this model can be considered a reliable predictive tool. It also highlights the importance of enamel remineralization therapies after orthodontic treatment, but also the importance of choosing personalized treatment strategies adapted to the enamel type. Full article

Background: The bond strength of orthodontic tubes to the enamel surface is essential for maintaining appliance stability, especially due to high masticatory forces on molars. Strong adhesion reduces the need for rebonding, shortening treatment time. This study aimed to evaluate the impact of tube base size and enamel sandblasting on bond strength in vitro. Methods: Eighty extracted permanent molar teeth were used for this study, divided into four groups of 20 samples each: M—small base tubes (non-sandblasted enamel), SM—small base tubes (sandblasted enamel), T—large base tubes (non-sandblasted enamel), and ST—large base tubes (sandblasted enamel). Shear bond strength was measured using the Mecmesim Multitesters 2.5-I device. Statistical analysis was conducted using IBM SPSS 27.0 software, applying ANOVA and Tukey’s post hoc test. Results: The highest bond strength (N) was recorded in the ST group, 85.51 ± 25.04 N, and the lowest in the M group, 50.23 ± 19.76 N. In terms of MPa, the SM group had the highest average value, 11.31 ± 3.57 MPa, while the T group had the lowest, 4.89 ± 1.33 MPa. ANOVA showed a statistically significant effect of tube base size on bond strength (p < 0.001), while sandblasting had no significant effect (p > 0.05). Conclusions: Larger base orthodontic tubes demonstrate stronger adhesion to enamel and are recommended for molars. Sandblasting the enamel does not significantly impact bond strength. Full article

Background: Resin infiltration has emerged as a micro-invasive strategy for managing enamel porosities, offering both therapeutic and aesthetic benefits. ICON^® (DMG, Hamburg, Germany) is the most widely used system; however, evidence on its penetration behavior in sound enamel remains limited. Objectives: This in vitro study aimed to evaluate the penetration depth and morphological pattern of ICON resin infiltration in sound human enamel, using quantitative morphometric analysis and scanning electron microscopy (SEM). Methods: Fourteen freshly extracted, caries-free anterior teeth were sectioned longitudinally. ICON^® resin infiltrate was applied to the buccal enamel surfaces according to the manufacturer’s protocol, while the lingual/palatal surfaces served as internal controls. Penetration depth was measured quantitatively on both mesial (surface A) and distal (surface B) halves, and SEM was used to assess resin–enamel interface morphology. Statistical analysis included the Shapiro–Wilk test, paired t-test, Pearson correlation, and percentage difference calculation. Results: The mean difference in penetration depth between surfaces A and B was −21.29 µm (p = 0.525), indicating no statistically significant variation. A strong positive correlation was observed between surfaces (r = 0.783, p = 0.001). The mean percentage difference was −3.57% (SD = 18.61%), suggesting minimal directional bias. SEM images confirmed continuous and homogeneous resin infiltration within enamel prisms. Post-hoc power analysis indicated 15.2% power, reflecting the impact of the limited sample size typical for SEM-based exploratory studies. Conclusions: Within the limitations of this in vitro investigation, ICON resin infiltration demonstrated uniform and consistent penetration in sound enamel, supported by both quantitative and SEM analyses. These findings validate its potential as a reliable preventive and micro-invasive biomaterial in dental practice, particularly for protecting enamel surfaces prior to orthodontic bracket bonding. Further clinical research with larger cohorts is recommended to confirm its long-term stability and prophylactic performance. Full article

The enamel of teeth affected by Molar–Incisor Hypomineralization (MIH) has been reported to have a higher protein content. Though a glass hybrid is recommended for restoring teeth with MIH in children, there is a lack of in vitro research on the influence of deproteinization on its marginal integrity. Therefore, this study aimed to evaluate whether enamel pretreatment with 5.25% NaOCl reduces the size of the marginal crevice of such restorations. Out of eight extracted teeth with severe MIH, restored using a glass hybrid (Equia Forte HT/GC), half underwent deproteinization. A stereoscopic and a scanning electron microscope (SEM) were used for sections analysis. The median value of the marginal crevice measured using stereoscopic microscopy (n = 17) was significantly lower for the deproteinized (6.78 μm) than for the standard-prepared specimens (12.61 μm), p = 0.008. On SEM images, the median marginal crevice (n = 10) was 69.40 μm versus 156.77 μm for the deproteinized and standard groups, respectively. The differences, however, were not statistically significant. This study only partially confirmed the hypothesis that pretreatment with NaOCl reduces marginal crevices between the Equia Forte HT material and hypomineralized hard tissues. Further studies on the effect of deproteinization on the marginal adaptation of glass hybrid materials are needed. Full article

Background/Objectives: The resin infiltration protocol was introduced as a minimally invasive approach for the treatment of incipient carious lesions using low-viscosity resins with high penetration coefficient. This study aimed to determine the effectiveness of resin infiltration in hypomineralized anterior teeth of paediatric patients, based on aesthetic improvement, colour change (ΔE), and visual perception. The risk of bias was assessed using the Newcastle–Ottawa and physiotherapy evidence database scales. The level of evidence was assessed using the grading of recommendations, assessment, development and evaluation tool. Methods: The following five databases were searched: Web of Science, Scopus, Embase, Cochrane, and PubMed. The review protocol was registered in PROSPERO (registration number: CRD42023405299). Results: The search identified 130 preliminary references related to the population, intervention, control, and outcome question, identified from the PubMed, Scopus, Embase, Web of Science, and Cochrane databases, respectively. In addition, two items were added from the grey literature. Ten articles met the eligibility criteria and were included in the qualitative analyses, and only three studies were included in the quantitative analyses. Positive results regarding stain-size reduction and colour improvement with resin infiltration (Icon^®; DMG, Hamburg, Germany), were reported in moderately severe lesions. Luminosity increased immediately after treatment, and the mean difference in total color change (ΔE), T0–T1 was significant (ΔE, 5.45; confidence interval, 1.94 to 8.96; p < 0.01). The most favourable clinical outcomes were observed following the initial resin infiltration. Moreover, the results were maintained at the 6 month follow-up. Conclusions: Infiltration resin can successfully mask white or white/creamy opacities characteristic MIH affected enamel, similar to those in carious enamel for which it was designed. It yields acceptable aesthetic results in anterior teeth with mild to moderate MIH lesions. Lack of predictability is the main limitation of this therapeutic option. 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: Molar–Incisor Hypomineralization (MIH) represents a developmental enamel defect of systemic origin, typically affecting the first permanent molars and often the incisors. Within the limitations of this study, several associations were observed between perinatal factors and MIH-related outcomes. However, most of these connections were not retained in adjusted analyses. Febrile illness during the first year of life showed a significant association with hypersensitivity. Methods: A structured 30-item questionnaire was distributed to mothers of 50 children diagnosed with MIH between February and March 2024. Data was analyzed using chi-square tests, with p < 0.05 considered significant, and univariate and multivariate logistic regressions at 95% confidence interval. Clinical diagnosis followed the Weerheijm (EAPD) criteria. Results: Maternal medication during pregnancy (antibiotics, antiepileptics, asthma drugs) was significantly associated with preterm birth (p = 0.01). Low birth weight correlated with tooth eruption disorders (p = 0.009) and perinatal complications such as hypoxia and respiratory distress (p = 0.0001). Fluoride application demonstrated a protective effect against discolorations (p = 0.005), caries (p = 0.002), and hypersensitivity (p = 0.01). In the multivariate model, febrile illness during the first year of life may be associated with hypersensitivity in MIH-affected teeth (aOR = 5.71, 95% CI: 1.01–32.27, p = 0.049). Conclusions: Maternal medication and perinatal complications, particularly low birth weight, were associated with MIH occurrence. Preventive strategies emphasizing maternal health, early screening, and remineralization-based therapies can mitigate long-term oral health impacts. Full article

Background/Objectives: Enamel defects in molar-incisor hypomineralization (MIH) have a multifactorial etiology involving environmental, systemic, and genetic factors. These alterations represent an aesthetic and emotional challenge, especially in anterior teeth. Resin infiltration has emerged as a minimally invasive treatment for MIH opacities, though outcome predictability remains limited. This study aims to analyze the baseline characteristics of MIH enamel defects and identify specific patterns that may predict clinical outcomes. Methods: This was a single-arm, prospective, observational clinical study with a six-month follow-up, with a total of 101 MIH-affected teeth treated with Icon^® resin infiltration. Opacities were analyzed using CIELAB color parameters (Lab*), including luminance, lesion extent, affected tooth type, opacity location, and patient age. Treatment success was assessed using simple linear regression models with generalized estimating equations, which were based on different covariates. Clinical success was defined as the combined achievement of a significant reduction in ΔE, a decrease in L* indicating reduced opacity brightness, and a reduction in the relative surface area of the lesion at six months. Results: White opacities showed greater reduction after infiltration than yellow and brown ones (p < 0.029). Larger lesions exhibited greater improvement (p < 0.007). Canines and lateral incisors achieved better masking (p < 0.001), and incisal opacities had superior outcomes (p < 0.019). Additionally, younger patients experienced a greater reduction (p < 0.026). Conclusions: Resin infiltration enhances the esthetics of anterior teeth with MIH in pediatric patients. While no single predictive pattern was identified, white opacities achieved greater luminance reduction and better integration with sound enamel. Factors such as age, tooth type, opacity location, lesion extent, and color significantly influence treatment effectiveness and esthetic perception. Full article

Background/Objectives: Visual examination remains the standard for caries detection, but its subjectivity limits reproducibility. Adjunctive methods may support objectivity, yet many require costly equipment or extensive training. BlueCheck (BC) liquid is a hemoglobin-based dye that binds reversibly to porous hydroxyapatite, producing a visible blue discoloration in demineralized enamel. This study aimed to evaluate the ability of BC liquid to detect initial occlusal caries lesions and assess lesion activity. Methods: An in vitro study was performed on 54 extracted permanent posterior teeth. Caries detection and lesion activity assessment were performed visually (International Caries Classification and Management System) and with BC liquid. Histology, including methyl red staining, served as the reference standard for lesion depth and activity. Agreement, sensitivity, specificity, and ROC analyses were calculated. Results: BC liquid showed almost perfect intra- and inter-examiner reproducibility (κ = 0.86). Overall agreement with visual examination was 92.6%, and agreement with histological activity assessment was 79.6%. For detection of initial lesions, BC liquid achieved sensitivity of 81.8% and specificity of 100%, with an AUC of 0.909. For activity assessment, BC liquid showed higher sensitivity than visual examination (89.5% vs. 60.5%), but lower specificity (75% vs. 100%), yielding an AUC of 0.822. Conclusions: Within the limitations of this in vitro study, BC liquid demonstrated good diagnostic accuracy and agreement with visual criteria for both detection and activity assessment of occlusal caries lesions. BC liquid may serve as an adjunctive tool for caries diagnosis, but further in vivo and longitudinal studies are required to validate its clinical applicability. Full article

Background: Pediatric syrups are frequently prescribed but may pose a risk to dental enamel due to their acidity and viscosity. Aim: To evaluate the erosive potential of commonly prescribed pediatric syrups on enamel from primary and permanent human teeth under ex vivo conditions. Design: Enamel–dentin blocks from sound primary and permanent teeth were assigned to nine groups (eight syrups and one control). Samples were immersed in their respective solutions four times daily for a 6-day exposure period. Mineral loss (ΔF) was assessed via Quantitative Light-Induced Fluorescence (QLF), surface roughness via profilometry, and morphological changes via scanning electron microscopy (SEM). Syrup pH and viscosity were also measured. Results: Significant ΔF changes were found only for dextromethorphan on primary enamel (p = 0.0054). No significant enamel loss was observed by profilometry. Surface roughness increased significantly with glycerin, distilled water, and azithromycin. Syrups showed a wide pH range (3.92–8.44) and varied viscosity, with ibuprofen and glycerin being the most viscous. Conclusions: Most pediatric syrups did not cause significant enamel demineralization or loss under short-term ex vivo exposure. However, increased surface roughness suggests that specific formulations may affect enamel texture, underscoring the need for preventive care in frequent users. Full article

Background and Clinical Significance: Advanced periodontitis with severe vertical bone loss and grade III mobility is usually managed by extraction and implant placement. Digital workflows and modern regenerative techniques have opened the possibility of preserving teeth that would traditionally be considered for extraction. This report describes a digitally guided modified intentional replantation (MIR) protocol applied to a maxillary tooth with severe periodontal involvement and unfavourable prognosis. Case Presentation: A 68-year-old male, non-smoker, with a history of heart transplantation under stable medical control, presented with generalized Stage IV, Grade C periodontitis. Tooth 21 showed >75% vertical bone loss, probing depths ≥ 9 mm, bleeding on probing, and grade III mobility. After non-surgical therapy and periodontal stabilization, a CAD/CAM-assisted MIR procedure was planned. Cone-beam computed tomography (CBCT) and a 3D-printed tooth replica were used to design a surgical guide for a new recipient socket. The tooth was atraumatically extracted, stored in chilled sterile saline, and managed extraorally for approximately 10 min. Apicoectomy and retrograde sealing with Biodentine^® were performed, followed by immediate replantation into the digitally prepared socket, semi-rigid splinting, and guided tissue regeneration using autologous bone chips, xenograft (Bio-Oss^®), enamel matrix derivative (Emdogain^®), and a collagen membrane (Bio-Gide^®). A conventional orthograde root canal treatment was completed within the first month. At 12 months, tooth 21 exhibited grade 0 mobility, probing depths of 3–4 mm without bleeding on probing, and stable soft tissues. Standardized periapical radiographs and CBCT showed radiographic bone fill within the previous defect and a continuous periodontal ligament-like space, with no signs of ankylosis or root resorption. The tooth was fully functional and asymptomatic. Conclusions: In this medically complex patient, digitally guided MIR allowed preservation of a tooth with severe periodontal involvement and poor prognosis, achieving favourable short-term clinical and radiographic outcomes. While long-term data and larger series are needed, MIR may be considered a tooth-preserving option in carefully selected cases as an alternative to immediate extraction and implant placement. Full article

Aim: This ex vivo study aimed to evaluate the effect of low-energy 445 nm diode laser irradiation on permanent fluoride retention in human enamel. Materials and Methods: Eighty caries-free extracted permanent human teeth were used to prepare 480 enamel discs (2 × 2 mm). Baseline fluoride content in untreated enamel specimens (control group E) was measured using particle-induced gamma-ray emission (PIGE). All specimens then received a topical application of acidulated phosphate fluoride for 5 min, followed by rinsing with double-distilled water for 1 min. Fluoride quantification was subsequently repeated. Specimens were randomly allocated into two groups: fluoridated only (EF; n = 240) and fluoridated plus laser-treated (EFL; n = 240). Each group was further subdivided based on storage conditions: either in air or in double-distilled water at 36 °C for 7 days. Laser irradiation was performed using a 445 nm diode laser in continuous-wave mode at 350 mW for 30 s, with a beam diameter of 10 mm, an energy density of 13.375 J/cm², and a power density of 0.445 W/cm². Results: At baseline, mean fluoride content across all specimens was 702.23 ± 201 ppm. Immediately after fluoridation, fluoride levels increased to 11,059 ± 386 ppm in the EF group and 10,842 ± 234 ppm in the EFL group, with no significant difference between groups. After 7 days of storage in air, fluoride retention decreased to 5714 ± 1162 ppm in EF and 5973 ± 861 ppm in EFL, again without significant difference. However, after 7 days of immersion in double-distilled water, the EF group exhibited complete loss of acquired fluoride, with values falling below baseline (337 ± 150 ppm). In contrast, the EFL group retained a substantial portion of the fluoride acquired during fluoridation (total 1533 ± 163 ppm), indicating that laser irradiation significantly prevented fluoride loss (p < 0.001). Conclusions: Low-energy 445 nm diode laser irradiation of fluoridated enamel significantly enhances fluoride retention under aqueous conditions simulating osmotic processes. Laser treatment preserved a substantial portion of fluoride acquired during fluoridation, whereas fluoridated but unlased enamel lost nearly all fluoride, with levels dropping below baseline. This approach may offer clinical benefits for improving enamel fluoride enrichment, thereby increasing resistance to acid challenge and reducing caries risk. Full article

Noonan syndrome is a relatively common genetic syndrome with clinical and genetic heterogeneity. Besides the characteristic features such as short stature, typical facial features, congenital heart defects, skeletal and ocular anomalies, various orodental manifestations occur with variable frequency. High-arched palate, malocclusions, micrognathism, giant cell lesions, and anomalous lateral incisors are frequently observed features, whereas supernumerary teeth, hypodontia, macrodontia, enamel hypoplasia, severe dental caries, impacted teeth, delayed eruption, taurodontism and odontoma have occasionally been reported. Here, we present a family with three affected members displaying variable dental manifestations carrying the same PTPN11 c.178G>A pathogenic variant. A 14-year-old and a 12-year-old, both female patients, presented high-arched palates, delayed dental eruption and caries. Moreover, the younger sibling exhibited frequently observed manifestations such as malocclusion and gingivitis, and further rare features like open-bite, micrognathia, and crowded teeth were present. The mother of the patients had periodontitis and enamel problems. Monitoring the oral health of the patients with NS is important, as they are prone to severe dental caries, gingival and other orodental problems. Therefore, initiating early orodental examination is highly recommended for patients with suspicion or diagnosis of NS. Full article