Search Results (104)

Background: Corrosion of orthodontic archwires raises biocompatibility concerns; yet, comparative multi-element data across manufacturers remain scarce. Methods: Ni, Cr, Fe, and Ti release was quantified by ICP-OES from SS and NiTi rectangular archwires (0.43 × 0.64 mm) from four manufacturers (Ormco, 3M Unitek, Dentaurum, and American Orthodontics) and immersed in artificial saliva (pH~7.0) and fluoride-containing saliva (+0.05% NaF) at six time points (days 1–35). Release was normalised to wire mass (mg g⁻¹). Non-parametric tests were applied. Results: NiTi wires released significantly more Ni than SS wires in +NaF at all time points (p = 0.029). An exploratory manufacturer effect on Ni release from NiTi was detected (Kruskal–Wallis H = 12.99, p = 0.005); American Orthodontics exceeded Dentaurum and Ormco. Ormco SS released ~3-fold more Fe than other SS wires (H = 13.68, p = 0.003). Ti was detectable exclusively in NiTi wires in +NaF; all specimens were below LOQ in pH~7.0. Cr release was uniformly low (0.017–0.023 mg g⁻¹). Conclusions: Manufacturer identity influences Ni and Fe release independently of alloy type. Fluoride selectively disrupts the NiTi passive film. These exploratory findings, derived from a single-specimen pilot design, may inform clinical material selection in nickel-sensitive patients pending replication. Full article

This study evaluated the biomechanically optimal insertion angle for miniscrew-assisted anterior intrusion by analyzing stress in the periodontal ligament (PDL) and alveolar bone. A three-dimensional finite element model from cone-beam computed tomography (CBCT) data, comprising maxillary bone, anterior dentition, and a bonded orthodontic appliance, and segmented 0.019 × 0.025-inch stainless-steel archwire were used. Titanium miniscrews (1.4 × 6 mm) were placed at 5 mm from the alveolar crest between the lateral incisor and canine. Four insertion angulations relative to the occlusal plane (30°, 60°, 90°, and 120°) were simulated under a 90 g intrusive force. Results demonstrated that while all configurations achieved intrusion with minor labial tipping and maintained miniscrew stability, stress localization was highly angle-dependent: the 90° insertion generated the highest central incisor PDL tensile stress and maximum cortical bone Von Mises stress; the 120° insertion yielded peak canine PDL Von Mises stress and maximum root displacement; and the 60° insertion localized peak stresses within the cancellous bone and the bone–implant interface. Miniscrews remained stable in all scenarios. While all tested miniscrew angulations provided stable anchorage for upper anterior teeth intrusion, the selection of insertion angle critically influenced stress patterns within the supporting tissues. Full article

This study compared the mechanical and thermal properties of new and retrieved multizone rhodium-coated superelastic nickel-titanium (NiTi) archwires across anterior and posterior segments. Using three-point bending tests, Scanning Electron Microscopy with Energy-Dispersive Spectroscopy analysis, and multiple linear regression, it was found that the posterior segments of new wires generated forces 0.50–0.80 N higher than those of anterior or retrieved specimens. While anterior segments exhibited higher austenite start and finish temperatures (by 6.15 °C and 5.21 °C, respectively) compared to posterior segments, these temperatures remained below average intraoral levels, and clinical retrieval did not significantly alter transformation temperatures. However, retrieved wires produced lower overall forces, likely due to surface cracking identified through microscopy. Ultimately, while posterior segments consistently generate higher forces than anterior segments, the observed reduction in force over time and the risk of surface degradation led to the conclusion that these archwires are not recommended for tooth movements exceeding 2 mm. Full article

This Finite Element Analysis (FEA) study examined the stability of Polyetheretherketone (PEEK) miniscrews and tissue response in the posterior maxilla under varying angulations. A Cone beam computed tomography (CBCT)-derived three-dimensional model of the fully dentate maxilla was generated, featuring anatomical structures (teeth, periodontal ligament (PDL), alveolar bone) and orthodontic components (brackets, transpalatal arch, archwires). PEEK miniscrews were positioned bilaterally in the regions of the second premolar-first molar and first molar-second molar. A force of 100 g was applied perpendicular to the archwire. Four insertion angulations (45°, 70°, 90°, and 110°) were simulated. FEA revealed a consistent posterior displacement pattern: crowns tipped distally and buccally, while roots moved mesially, with intrusion. The first molar’s PDL peaked at 110°. Cortical bone stress was greatest in molars (1.41 × 10⁵ Pa at 70–110°). Cancellous bone stress peaked under 70° loading in the second molar (1.25 × 10⁵ Pa). PEEK miniscrews exhibited minimal deformation and low interfacial stress, confirming stable anchorage across all angles. Posterior PEEK miniscrews demonstrated excellent stability across all insertion angles, with 70° providing optimal biomechanical efficiency for intrusion. The first molar’s PDL experienced the highest stress concentrations at extreme angles. These findings offer clinical guidance for miniscrew placement to achieve effective intrusion while maintaining tissue safety. Full article

Background: Orthodontic appliances introduce new surfaces into the oral cavity that can modulate biofilm formation and potentially increase the risk of white spot lesions. Material-dependent differences in surface roughness, wettability and geometry may influence early colonization by Streptococcus mutans, a key cariogenic pathogen. Objectives: To compare early adhesion and biofilm formation of Streptococcus mutans on five commonly used orthodontic materials: stainless-steel (SS) and nickel–titanium (NiTi) archwires, metallic and ceramic brackets, polymethyl methacrylate (PMMA) acrylic resin. Materials and Methods: Standardized specimens were prepared, polished when applicable, sterilized, and conditioned in artificial saliva. The tested materials included SS and NiTi archwires (3M Unitek, Monrovia, CA, USA), metallic and ceramic brackets (Ormco, Orange, CA, USA), and PMMA acrylic resin (GC Corporation, Tokyo, Japan). Early adhesion (CFU), biofilm biomass (crystal violet), and metabolic activity (XTT) were quantified after incubation with S. mutans. Surface roughness (Ra) and contact angle were measured, and correlations with microbiological endpoints were assessed. Results: A clear material-dependent gradient was observed. Stainless steel showed the lowest early adhesion and biofilm formation (5.20 ± 0.28 log₁₀ CFU·cm⁻²; CV OD₅₉₀ = 0.60 ± 0.14), followed by NiTi, metallic brackets, and ceramic brackets, while PMMA exhibited the highest bacterial load and biofilm biomass (6.09 ± 0.32 log₁₀ CFU·cm⁻²; CV OD₅₉₀ = 1.10 ± 0.17). Overall differences between materials were statistically significant (p < 0.0001). Surface roughness and contact angle positively correlated with bacterial colonization. Conclusions: Early S. mutans colonization is strongly influenced by orthodontic material properties, with smoother and less hydrophobic surfaces showing reduced biofilm formation. PMMA and bracket structures may pose higher cariogenic risk during treatment. These findings support the development of surface-engineered or biofilm-resilient orthodontic materials. Full article

Orthodontic treatment, offering significant benefits for oral function and facial aesthetics, is in high demand among both adolescent and adult populations. Orthodontic appliances pose challenges for maintaining oral hygiene and increase the risk of dental and periodontal diseases. With advances in dental materials and the use of nanoparticles, a significant amount of research has focused on modifying orthodontic appliances with nanoparticles to reduce bacterial adhesion and biofilm formation. Silver nanoparticles are one of the most popular antibacterial materials in medical research. This article presents current evidence on silver nanoparticle-incorporated orthodontic appliances, including brackets, molar bands, archwires, elastomeric ligatures, mini-implants, and acrylic retainers. Silver nanoparticles and modified silver nanoparticles exhibit robust antibacterial activity when applied to the surfaces of orthodontic appliances. However, there are exceptions in which, on a few orthodontic appliances, the silver nanoparticle incorporation actually increased biofilm formation. Moreover, a silver nanoparticle incorporation may introduce adverse effects, such as cytotoxicity, and increase surface roughness. It is also worth noting that most of the studies were conducted in vitro. Long-term clinical studies are necessary to evaluate the stability, safety, and clinical efficacy of silver nanoparticle-incorporated orthodontic appliances under real-world conditions. Full article

To elucidate the corrosion mechanism of orthodontic archwire in fluoride-containing environments, the friction and wear behavior of archwires following corrosion in fluoride-containing oral care products was investigated. Stainless steel archwires were soaked in solutions of fluoride-free toothpaste, fluoride toothpaste, fluoride-free mouthwash, fluoride mouthwash, and sodium monofluorophosphate, followed by friction testing against brackets. The average friction coefficient of the archwire–bracket tribopair increased gradually from 0.17 to 0.28 with prolonged immersion time in the fluoride-containing solution, accompanied by a progressive increase in the wear scar area on the archwire surface. In the fluoride toothpaste solution, the archwire exhibited a corrosion potential and current density of –301.8 mV and 0.348 μA/cm², respectively, indicating a higher susceptibility to corrosion. Analysis of wear debris revealed significant enrichment of fluorine and oxygen elements on the archwire surface after exposure to fluoride-containing solutions, consistent with pronounced corrosion damage. Integration of friction results and surface characterization elucidated the corrosion mechanism in fluoride-containing environments. It was proposed that fluoride ions facilitated the formation of micro-batteries, while active fluoride species accelerated the dissolution of nickel from the archwire surface and promoted oxygen accumulation, thus driving sustained electrochemical corrosion. This progressive surface degradation ultimately exacerbated the friction and wear of the archwire–bracket tribopair. Full article

Background: The development of the curve of Spee (CoS) is influenced by skeletal morphology, orofacial growth, tooth eruption timing, mandibular relationships, overbite, and neuromuscular development. This systematic review aims to determine the most effective orthodontic methods in correcting the curve of Spee. Methods: The systematic review protocol was registered on the PROSPERO platform and conducted according to the Cochrane and PRISMA guidelines. For its development, a standardized search was performed across different databases (MEDLINE, Cochrane Library, Embase and Web of Science) and grey literature. The risk of bias was assessed using Faggion, Jr.’s guidelines for in vitro and in silico studies of dental materials, and the Rob-2 and ROBINS-1 tools for clinical studies. Results: The initial search found 748 studies, with 44 selected after full-text review. Of these, 22 were included in the quantitative analysis, assessing the effectiveness of braces (with or without extractions) and invisible aligners. Key methods for correcting the curve of Spee include various orthodontic archwires (nickel–titanium (NiTi), stainless steel, beta-titanium), continuous and segmented techniques, reverse curve archwires, aligners, and treatment modalities including extraction protocols. Most in vitro studies and randomized studies had a high risk of bias, and non-randomized studies showed moderate to high bias risk. Conclusions: The results suggest that conventional techniques, particularly non-extraction approaches, may be more effective than aligners in correcting the curve of Spee, although the available evidence remains limited. Full article

To mitigate the adverse effects of immersion in fluoride-containing solutions on the surface corrosion of orthodontic stainless steel archwires, carbon films were fabricated on these archwires under various deposition times and substrate bias voltages using a self-designed plasma sputtering system. Structural analysis revealed that the carbon films deposited at lower substrate bias voltages were classified as amorphous carbon films, whereas those fabricated at higher substrate bias voltages were identified as graphene nanocrystalline carbon films. Particularly, immersion tests and electrochemical experiments demonstrated that carbon film prepared at a substrate bias voltage of +50 V for 80 min exhibited exceptional corrosion resistance. Furthermore, a low friction coefficient and low wear rate were obtained even after soaking in a fluoride toothpaste mixed solution. The mechanisms underlying the corrosion resistance and friction properties of these superior carbon films were thoroughly investigated. This study provides valuable insights into the application of carbon film for reducing friction and wear while enhancing corrosion resistance, thus promoting their practical clinical applications in coated orthodontic stainless steel archwires. Full article

Background: Patient discomfort during the initial phase of orthodontic treatment is a common concern and may influence compliance. Archwire selection plays a critical role in modulating pain perception. This study aimed to compare immediate and dynamic pain perception among patients undergoing initial orthodontic leveling using three types of nickel–titanium archwires with different mechanical properties and cross-sectional dimensions. Methods: Forty-eight patients undergoing fixed appliance therapy were enrolled in a single-blind comparative clinical study. Participants completed a two-part, pilot-tested questionnaire assessing immediate (Day 4) and dynamic (Day 8) pain after the first archwire placement. Group differences were analyzed with Kruskal–Wallis and Bonferroni-adjusted Mann–Whitney U tests (α = 0.05). Results: TriTanium^® was consistently associated with lower pain across functional tasks and had significantly lower overall pain than both Bio-Active^® and 0.014-inch single-force round Ni-Ti (Bonferroni-adjusted). Bio-Active^® was intermediate and did not differ from 0.014-inch round; its reduction relative to the round wire showed a non-significant trend. No correlation was found between archwire size and pain intensity. Conclusions: The type and mechanical behavior of the archwire, rather than its cross-sectional dimension, influence patient discomfort during the initial leveling phase. Multiforce shape-memory archwires such as TriTanium^® may offer improved comfort and should be considered when planning early-stage orthodontic treatment. Full article

The biocompatibility of orthodontic archwires is crucial for ensuring patient safety and the long-term success of orthodontic treatment. This study evaluated the biocompatibility of stainless steel (SS) and nickel–titanium (Ni-Ti) orthodontic archwires, as well as stainless steel metal brackets, before and after the application of a graphene coating. The assessment was based on the materials’ effects on a fibroblast cell line and on the development of a foetal chicken egg embryo. Fibroblasts that had been in temporary contact with steel and NiTi archwires after CW-CVD (cold wall chemical vapour deposition) treatment exhibited changes in morphology in the presence of the material. The materials exhibited moderate cytotoxicity. For metal brackets, the treated samples caused stronger cytotoxic changes in the culture. Unlike graphene-coated implants, where cells were found to directly adhere to the surface, the embryonic tissues did not treat the non-graphene-coated implants as an adhesive material. This study suggests that depositing carbon-based coatings, including graphene, on stainless steel archwires may reduce the cytotoxicity of orthodontic components. Using graphene increases adhesion of the implant surface to membrane-derived cells and the embryonic yolk and does not inhibit the further development of the chicken egg embryo. Full article

Objectives: This study investigated the use of artificial intelligence (AI) in the design of lingual bracket indirect bonding trays and its association with bracket transfer accuracy using three-dimensional (3D) printing. Methods: Digital impressions of patient’s dental arches were captured using an intraoral scanner, and orthodontic setups were virtually constructed. Brackets were virtually positioned in their ideal locations using the digital setups guided by virtual archwire templates. Indirect bonding trays were automatically generated using the AI-powered Auto Creation function of the Medit Splints application, which analyzes anatomical features to streamline design. Bracket transfer accuracy was evaluated in vivo by comparing planned and actual bracket positions across grouped and individual tray configurations. Linear and angular deviations were measured using conventional 3D inspection software. Results: Most bracket transfer errors were within clinically acceptable thresholds, although torque accuracy remained suboptimal. Grouped trays generally exhibited greater precision than individual trays in several dimensions. Conclusions: These findings support the application of AI-assisted design tools to enhance digital workflows and improve consistency in appliance fabrication. Full article

Fluoride mouthwashes are often recommended by dental professionals due to their proven benefits for oral hygiene. However, it is vital to acknowledge that these products may have undesirable effects on orthodontic treatment outcomes, particularly by altering the biomechanical properties of orthodontic devices and their components. To gain a comprehensive understanding of this potential issue, an extensive and systematic search was conducted across seven distinct databases. PRISMA extension for scoping reviews (PRISMA ScR) guidelines were followed. Following a detailed evaluation and careful scrutiny of the available evidence, a total of seven relevant studies met the inclusion criteria and were incorporated into the current scoping review. Findings indicated that regular intraoral use of fluoride-containing mouthwashes could lead to heightened corrosion and greater release of metal ions from stainless-steel brackets and nickel–titanium (NiTi) archwires. Additionally, the mechanical properties and structural integrity of titanium–molybdenum alloy (TMA) wires were negatively influenced by exposure to fluoride mouthwashes. Although existing evidence highlights these potential drawbacks, there remains a clear necessity for additional comprehensive research. Given the possibility that fluoride mouthwashes could adversely influence orthodontic treatment effectiveness, orthodontists and dental clinicians must exercise cautious judgment and deliberate consideration when prescribing fluoride-based mouthwashes for patients undergoing orthodontic therapy. Full article

Nickel-containing orthodontic archwires, particularly those made of nickel-titanium (NiTi) and stainless steel (SS), play a crucial role in orthodontic treatment using the fixed technique due to their mechanical properties. However, concerns regarding nickel-induced allergic reactions, cytotoxicity, and metal ion release, especially nickel-related ones, persist. This narrative review aims to explore recent findings on nickel release from orthodontic appliances, building upon prior systematic reviews by analyzing both in vitro and in vivo studies under various environmental conditions. The databases Web of Science, Scopus, and PubMed were searched for relevant studies that examined the relationship between nickel ion release from nickel-containing archwires and various environmental conditions. The studies found indicate that while metal ion release occurs during short-term treatment, the levels are lower than harmful thresholds, with factors such as pH, corrosion, length of treatment, and environmental influences affecting release rates. Despite this, long-term studies are few and are usually conducted only in an in vitro or in vivo environment, but not both. To establish causal relationships regarding metal ion release, in vivo monitoring of ions like Ni is critical, with further research needed to assess its prolonged effects. Furthermore, collaborative efforts among practitioners, researchers, and regulatory bodies are vital for developing evidence-based guidelines for orthodontic material selection, prioritizing patient safety and addressing metal ion release risks. Full article

Clear aligner treatment seems to be a good option for the periodontal patient by the reason of being removable. Multibracket appliances are more difficult to mantain clean and some bacteria might prefer to adhere on the archwire. A systematic review was carried out using 4 electronic databases (Pubmed-Medline, Scopus, Cochrane and Web of Science). The selected trials included quantitative (Shannon index, Simpson index, relative abundances) and/or qualitative (alpha and beta diversity) analysis in patients using clear aligners and multibracket appliances. Initially, a total of 123 articles were found after selecting clinical trials. The inclusion and exclusion criteria were applied by two authors. Finally, 20 articles were selected for the systematic review. The results showed that clear aligner treatment produced less dysbiosis in the selected bacteria compared to multibracket appliances. However, some microbiological changes were observed in some articles during clear aligner use. Oral dysibiosis was related with intestinal dysbiosis, inflammatory response and even cancer. The Firmicutes/Bacteroidetes ratio showed to have a very important role in this development. Periodontitis is also a bacterial disease and clear aligners were recommended to periodontal risk patients. Clear aligner treatment obtained less supra and subgingival biofilm changes compared with multibracket appliances but some bacteria were altered during treatment. Full article