Assessing color stability of orthodontic esthetic wires in different staining solutions.

BACKGROUND: Esthetic orthodontic wires are preferred for their ease to fit in with natural tooth color, but their susceptibility to staining in the oral environment poses a concern. Various Coatings such as Teflon and Epoxy aim to enhance appearance and biocompatibility but may still result in discoloration. Understanding the color stability of these wires under different staining conditions is crucial for a better and enhanced treatment plan. OBJECTIVE: This study intended to assess the color stability of esthetic orthodontic wires under various staining solutions that are often used in daily life. METHOD: Color changes of Teflon and Epoxy-coated esthetic orthodontic wires were meticulously measured at baseline, 7, 14, and 21-day intervals utilizing the precise CIE Lab* color measurement system. A total of thirty-two samples of wires from each brand were prepared (n= 8/group) and immersed in staining solutions (coffee, tea, cola, and saffron). The color change within and between the groups was statistically evaluated (p< 0.05). RESULTS: Significant variations in color stability were observed across different staining solutions. Saffron emerged as the most potent agent, inducing the most pronounced color changes, whereas cola demonstrated the least impact. Furthermore, Epoxy-coated wires consistently exhibited superior color stability compared to their Teflon-coated counterparts across all staining solutions and time intervals. CONCLUSION: This study underlines the significance for orthodontists to consider staining agents' possible effects on orthodontic wires into account when selecting the orthodontic wires. The findings suggest that Epoxy-coated wires hold promise in mitigating discoloration issues during orthodontic therapy.

MRI susceptibility artefacts caused by orthodontic wire.

OBJECTIVES: To evaluate magnetic susceptibility artefacts produced by orthodontic wires on MRI and the influence of wire properties and MRI image sequences on the magnitude of the artefact. METHODS: Arch form orthodontic wires [four stainless steels (SS), one cobalt chromium (CC) alloy, 13 titanium (Ti) alloys] were embedded in a polyester phantom, and scanned using a 1.5-T superconducting magnet scanner with an eight-channel phased-array coil. All wires were scanned with T1-weighted spin echo (SE) and gradient echo (GRE) sequences according to the American Society for Testing and Materials (ASTM) F2119-07 standard. The phantom was also scanned other eight sequences. Artefacts were measured using the ASTM F2119-07 definition and OsiriX software. Artefact volume was analyzed according to metal composition, wire length, number of wires, wire thickness, and imaging sequence as factors. RESULTS: With SE/GRE, black/white artefacts volumes from all SS wires were significantly larger than those produced by CC and Ti wires (P < 0.01). With the GRE, the black artefacts volume was highest with the SS wires. With the SE, the black artefacts volume was small, whereas white artefacts were noticeable. The cranio-caudal extent of the artefacts was significantly longer with SS wires (P < 0.01). Although a direct relationship of wire length, number of wires and wire thickness with artefact volume was noted, these factors did not influence artefact extension in the cranio-caudal direction. CONCLUSIONS: Ferromagnetic/paramagnetic orthodontic wires create artefacts due to local alteration of magnetic field homogeneity. The SS-type wires produced the largest artefacts followed by CC and Ti.

Trismus caused by migration of orthodontic archwire into the infratemporal fossa: a case report.

INTRODUCTION: Soft tissue injuries are known complications of orthodontic treatment. Most of the injuries are mild, but severe complications can arise from deeper penetration or dislodgement of brackets and other foreign bodies into the surrounding tissues of the oropharynx and infratemporal fossa. PATIENT CONCERNS: The patient, accompanied by his parents, presented to the Children's Emergency Department with the concern of gradual limitation of mouth opening and eventual trismus, which occurred over a span of 2 weeks. CLINICAL FINDINGS: The patient presented with trismus and slight discomfort at the left cheek region. He reported a history of gradual limitation to his mouth opening 2 weeks prior. He was wearing upper and lower fixed orthodontic appliances and the left distal end of the maxillary archwire was found to have migrated into the left infratemporal fossa. PRIMARY DIAGNOSES: Left medial pterygoid muscle inflammation, or bleeding and haematoma formation, or infection within the infratemporal region. INTERVENTIONS: The maxillary archwire was removed in the Children's Emergency Department and a computed tomography (CT) scan performed subsequently confirmed the diagnosis of left medial pterygoid muscle inflammation. The patient was started on an intravenous (IV) antibiotic and a 2-day course of IV dexamethasone to reduce the muscle inflammation. OUTCOME: By the second day, the patient was able to achieve a mouth opening of 6 mm, and by the second week, the mouth opening had returned to normal. CONCLUSION: The potential risk of soft tissue injury and complications from orthodontic treatment is generally mild and limited. Soft tissue injuries can be avoided with careful management by the operator with the proper precautions taken. Clinicians should be familiar with the surrounding soft tissue anatomy and be aware of the potential for more severe complications and provide management or referral to the appropriate specialty accordingly.

Application of Robotics in Orthodontics: A Systematic Review.

Robotics has various applications in dentistry, particularly in orthodontics, although the potential use of these technologies is not yet clear. This review aims to summarize the application of robotics in orthodontics and clarify its function and scope in clinical practice. Original articles addressing the application of robotics in any area of orthodontic practice were included, and review articles were excluded. PubMed, Google Scholar, Scopus, and DOAJ were searched from June to August 2023. The risk of bias was established using the risk of bias in non-randomized studies (ROBINS) and certainty assessment tools following the grading of recommendations, assessment, development, and evaluation (GRADE) guidelines. A narrative synthesis of the data was generated and presented according to its application in surgical and non-surgical orthodontics. The search retrieved 2,106 articles, of which 16 articles were selected for final data synthesis of research conducted between 2011 and 2023 in Asia, Europe, and North America. The application of robotics in surgical orthodontics helps guide orthognathic surgeries by reducing the margin of error, but it does not replace the work of a clinician. In non-surgical orthodontics, robotics assists in performing customized bending of orthodontic wires and simulating orthodontic movements, but its application is expensive. The articles collected for this synthesis exhibited a low risk of bias and high certainty, and the results indicated that the advantages of the application of robotics in orthodontics outweigh the disadvantages. This project was self-financed, and a previous protocol was registered at the PROSPERO site (registration number: CRD42023463531).

Comparisons of Two Different Treatment Methods for Impacted Maxillary Canines: A Retrospective Study.

Background: The impaction of the maxillary canine is a common occurrence, and orthodontists must be prepared to manage it. The purpose of this article is to present a study of the efficacy of a double-wire orthodontic appliance compared to a control group in the alignment of impacted maxillary canines in the dental arch. Methods: To diagnose an impacted maxillary canine, a panoramic radiograph was taken and a detailed analysis was performed by the same orthodontist. This article presents the results of 28 impacted maxillary canines with inclusion criteria of A2 (tooth angulation to the midline 16°-45°), V1 (vertical height of the tooth crown above the cementoenamel junction but less than half the length of the root of the maxillary lateral incisor), and O3 (medial position of the canine crown of more than half but less than the entire root width of the lateral incisor) positions in 21 patients (7 males and 14 females) with a mean age of 14.02 years (SD = 1.61) who were treated by the same orthodontist for impacted maxillary canines using a fixed double-wire orthodontic appliance. The analyzed data were compared with the control group (treated with a fixed orthodontic appliance and active ligature), which was matched for pretreatment age and the A2, V1, and O3 positions of the impacted maxillary canine. Results: With both methods, the impacted maxillary canines were aligned and guided into a correct position in the dental arch, but the mean active orthodontic traction of 31 ± 4.2 weeks in the SG was statistically significantly shorter (p < 0.05) in comparison to 37 ± 6.3 weeks in the CG, and the number of visits was statistically significantly (p < 0.05) fewer in the SG (5 ± 2) than in the CG (11 ± 5). Conclusions: The findings of this study are important to the field of orthodontics and show that the alignment of impacted maxillary canines with A2, V1, and O3 positions can be achieved with both methods, but with the double-wire appliance, the treatment time was shorter and the number of visits was statistically significantly fewer. The results of this study suggest that this approach may be more efficient and cost-effective compared to conventional methods.

Comparative Evaluation of Antibacterial and Anti-Adherent Properties between Titanium Oxide, Silver Dioxide-Coated, and Conventional Orthodontic Wires Against Streptococcus Sanguis Causing Gingivitis.

Objective: To compare the antibacterial and anti-adherent properties of conventional stainless steel (SS) orthodontic wires and surface-modified silver dioxide-coated and titanium oxide-coated SS orthodontic wires against Streptococcus sanguis causing gingivitis. Materials and Methods: The study used 60 orthodontic SS wire specimens, organized into six groups of ten each. The control group had uncoated wires, and the experimental group featured wires coated with silver dioxide and titanium oxide. Surface modification was done using DC sputtering, and microbiological tests assessed the antibacterial and anti-adherent properties of the AgO2- and TiO2-coated wires. Results: This study demonstrated the antibacterial effect against S. sanguis in orthodontic wires coated with the photocatalytic AgO2 and TiO2 compared to the uncoated wires. Also, this study demonstrated an anti-adherent effect in the AgO2- and TiO2-coated orthodontic wires. Moreover, the bacterial accumulation on orthodontic wires coated with AgO2 and TiO2 was lower compared to that on the uncoated wires. Conclusion: During orthodontic treatment, the formation of dental plaque can be prevented by coating the surface of stainless-steel orthodontic wires with photocatalytic AgO2 and TiO2. Compared to silver dioxide, the titanium oxide-coated SS orthodontic wires showed better antibacterial and anti-adherent properties.

Elemental composition, corrosion resistance and mechanical properties of computer-aided design and computer-aided manufacturing fixed retainers versus conventional fixed retainers.

PURPOSE: To investigate the elemental composition, corrosion resistance, and mechanical properties of computer-aided design and computer-aided manufacturing (CAD-CAM) retainers versus conventional fixed retainers (FRs). METHODS: Eight different retainer wires were investigated. Energy dispersive X-ray spectroscopy was used to determine the elemental composition. Leakage was analysed according to ISO 10271:2020 guidelines. Hardness was tested using the Vickers method with a load of 0.3 kg. The tensile force and tensile strength were evaluated. Multiple comparisons among wires of hardness, tensile force, and strength were conducted using the Welch t-test, with Bonferroni correction. RESULTS: Nickel was present in all wires. The CAD-CAM-FR wire, which contained more nickel than the other wires, had no measurable leakage. The gold-plated wires had the highest total leakage, but did not exceed the ISO standard limit. The hardness of the stainless-steel twisted wires was the highest and that of the CAD-CAM-FR wire was the lowest. The tensile strength of the CAD-CAM-FR wire was significantly lower than that of the other wires and similar to the other twisted-wire retainers. CONCLUSION: The CAD-CAM-FR wire is likely to have high corrosion resistance and flexibility due to its low hardness.

Students' perception on flipped classroom with formative assessment: A focus group study.

OBJECTIVE: To explore students' perception on the implementation of flipped classroom (FC) combined with formative assessment during the undergraduate teaching of orthodontic wire-bending skills. METHODS: Third-year undergraduate dental students were taught wire-bending skills via FC teaching method using a series of pre-recorded online video demonstrations. As part of the formative assessment, the students were given the results and assessment rubrics of their prior wire-bending assessment before every subsequent session. Purposive sampling method for focus group discussion was used to recruit eight students comprising four high achievers and four low achievers. Strengths, weaknesses and suggestions for improvement of the FC with formative assessment were explored. Data were transcribed and thematically analysed. RESULTS: Students perceived that FC allowed for a more convenient and flexible learning experience with personalised learning and improved in-class teaching efficiency. The pre-recorded online videos were useful to aid in teaching wire-bending skills but lacked three-dimensional representation of the wire-bending process. Students suggested better standardisation of instructions and access to the marking rubric before and after assessment. CONCLUSIONS: FC teaching with continuous formative assessment and constructive feedback as a form of personalised learning was viewed favourably by students. The implementation of periodic individual feedback can further enhance their learning experience.

Periodontitis induced by orthodontic wire ligature drives oral microflora dysbiosis and aggravates alveolar bone loss in an improved murine model.

Aim: To assess the contribution of polymicrobial disruption of host homeostasis to periodontitis progression in orthodontic wire ligation murine model. Methods: Orthodontic wire rings were inserted between the first and second molars of mice for 18 days for the orthodontic wire ligation mouse model, and Pg injection model and Pg-LPS injection model were used as controls. Alveolar bone loss and periodontal inflammation were analyzed by micro-CT, histological staining and qRT-PCR. Further, pyrosequencing of 16S rRNA gene amplicon was used to analyze the development of oral microorganism dysbiosis in the mice. Results: Micro-CT, TRAP staining and qRT-PCR showed that orthodontic wire ligation model led to more severe alveolar bone loss than Pg and Pg-LPS models.H&E staining and qRT-PCR demonstrated that stronger inflammatory response was induced by the orthodontic wire treatment compared to the other models. In addition, pyrosequencing of 16S rRNA gene amplicons revealed that the composition of oral microbiota presented a transition as the disease progressed and significant differences emerged in oral microbiota communities between orthodontic ligature mice and healthy controls. Furthermore, antibiotic treatment decreased both inflammation and alveolar bone loss in response to microbial community dysbiosis. However, no significant difference in bacterial community composition was observed in Pg and Pg-LPS models. Conclusions: Orthodontic wire ligation drove oral microbial community transitions that mimicked polymicrobial communities characterized by polymicrobial synergy and dysbiosis. Our improved model is suitable for further study of pathogenesis of periodontitis and exploration of corresponding treatment strategies.

MRI compatibility of orthodontic brackets and wires: systematic review article.

BACKGROUND: Before the magnetic resonance imaging (MRI) examination fixed orthodontic devices, such as brackets and wires, cause challenges not only for the orthodontist but also for the radiologist. Essentially, the MRI-safe scan of the fixed orthodontic tools requires a proper guideline in clinical practice. Therefore, this systematic review aimed to examine all aspects of MRI-safe scan, including artifact, thermal, and debonding effects, to identify any existing gaps in knowledge in this regard and develop an evidence-based protocol. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement was used in this study. The clinical question in "PIO" format was: "Does MRI examination influence the temperature of the orthodontic devices, the size of artifacts, and the debonding force in patients who have fixed orthodontic bracket and/or wire?" The search process was carried out in PubMed, PubMed Central, Scopus, and Google Scholar databases. The search resulted in 1310 articles. After selection according to the eligibility criteria, 18 studies were analyzed by two reviewers. The risk of bias was determined using the Quality In Prognosis Studies tool. RESULTS: Out of the eligible 18 studies, 10 articles examined the heating effect, 6 were about the debonding effect, and 11 measured the size of artifact regarding brackets and wires. Considering the quality assessment, the overall levels of evidence were high and medium. The published studies showed that heating and debonding effects during MRI exposure were not hazardous for patients. As some wires revealed higher temperature changes, it is suggested to remove the wire or insert a spacer between the appliances and the oral mucosa. Based on the material, ceramic and plastic brackets caused no relevant artifact and were MRI-safe. Stainless steel brackets and wires resulted in susceptibility artifacts in the orofacial region and could cause distortion in the frontal lobe, orbits, and pituitary gland. The retainer wires showed no relevant artifact. CONCLUSIONS: In conclusion, the thermal and debonding effects of the fixed orthodontic brackets and wires were irrelevant or resoluble; however, the size of the artifacts was clinically relevant and determined most significantly the feasibility of fixed brackets and wires in MRI examination.

Surface Evaluation of Orthodontic Brackets Using Texture and Fractal Dimension Analysis.

The surface topography of orthodontic brackets can have a significant impact on both the effectiveness of the therapy and the behavior of these elements in the oral cavity environment. In this situation, striving to obtain the most uniform, smooth surface in a repeatable manner for each manufactured element should be a sine qua non condition for each supplier of orthodontic brackets. Therefore, it is necessary to analyze the surfaces of orthodontic brackets using different methods. One of them-that is relatively simple and repeatable-is the analysis of the fractal dimension and the analysis of the textures of the optical images on the surface. In the presented study, fractal dimension analysis and texture analysis were performed by selecting four brackets from three different manufacturers (Mini Sprint, Sprint, Nu-Edge, Orthos SS). The area of each bracket slot was analyzed at six predefined points. The smoothest and most uniform and reproducible surface structure was shown by the Mini Sprint bracket. On the other hand, Sprint brackets showed the least homogeneous and least repeatable surface structure.

Surface Evaluation of Orthodontic Wires Using Texture and Fractal Dimension Analysis.

Mechanical properties of orthodontic wires can have a very significant impact both on the resistance of the entire appliance to the oral cavity conditions and directly on the effectiveness of the therapy. Striving to achieve repeatability of mechanical characteristics of orthodontic wires of a given type should be an obligatory condition in their production. To achieve it, these components should be thoroughly analyzed using various mechanical tests. Twenty-four steel and nickel-titanium orthodontic wires from four different manufacturers were examined. Each wire was subjected to fractal dimension analysis and texture analysis. The two sides of each wire were compared against each other, as well as in terms of variation in the surface area for each wire type made by different manufacturers. Most wires showed significant variation in fractal dimension and texture, both when comparing two sides of the same wire and between individual wires of a given type made by a single manufacturer. When conducting research and clinically using orthodontic wires made of Ni-Ti alloys and stainless steel, it should be assumed that the surface of orthodontic wires shows a significant degree of variation, and wires of the same type from the same manufacturer may differ significantly in this respect.

In Vitro Ion Release of Wires in Removable Orthodontic Appliances.

Various orthodontic wire compositions and configurations are present on the market for removable appliances; however, there have still been only few studies focusing on the effect of resin color and additives such as glitter on corrosion of metallic wires under different conditions. Thus, the aim of the study was to compare concentrations of released ions (aluminium, chromium, nickel) in a corrosive medium under three different conditions: non-loaded wires, loaded wires, and non-loaded wires treated with Kukis® cleaning tablets. Six different wires made of three types of steel alloy were embedded in PMMA resin leaving one centimetre of each wire emerging from the resin to come into contact with the corrosive medium. Glitter particles were added to half of the produced test specimens. For the unloaded test series, five specimens of each group were covered in a petri dish with 50 mL of corrosive medium (pH 2.3) following EN-ISO 10271 for seven days at 37 °C. The wires for the mechanically loaded test specimens overlapped the resin by 5 cm and were clamped into a time-switched electric drive for a defined period of time before the samples were taken after a testing time of 7 days. In the third group, unloaded test specimens were transferred from their petri dishes into the prepared Kukis® solution every 24 h before being stored in the corrosive medium. Inductively coupled plasma mass spectrometry (ICP-MS) was used to quantify the specific ions in the corrosive solution. Statistical analysis showed that the mechanical loading of all wires could significantly raise the diffusion of ions into the corrosive medium. The colour of the resin did not affect the concentration of the released ions. The Kukis® cleaning tabs could not lower the corrosion of the tested metals, as some of the wires were corroded even more using the brace cleanser. Glitter-containing test specimens showed significantly higher amounts of aluminium. Mechanical loading as well as the presence of glitter particles in the resin significantly affected ion concentrations.

The effect of live demonstration and flipped classroom with continuous formative assessment on dental students' orthodontic wire-bending performance.

BACKGROUND: Wire-bending skills is commonly taught through live demonstrations (LD) though flipped classroom (FC) method has gained popularity. Continuous formative assessment promotes personalised learning via closely monitored progress, with the identification of students' strengths and weaknesses. This study aims to evaluate the effects of LD and FC teaching methods, supplemented with continuous formative assessment, on dental students' learning of wire-bending skills for six types of removable orthodontic appliance components. A deeper understanding of the relative effectiveness between LD and FC teaching methods can help identify the most appropriate method to achieve student learning objectives, which is especially important given the current Covid-19 pandemic. METHODS: Forty third-year undergraduate dental students were randomly assigned into FC (n = 20) or LD (n = 20) cohort. Each student attended six teaching sessions, each to teach students' competency in fabricating one type of wire component, for a total competency in fabricating six wire components over the course of six teaching sessions. Either LD or FC teaching methods were used. After each session, wire assignments had to be submitted. Wire assignments were then evaluated using a blinded wire-bending assessment protocol. As part of their formative assessment, the assessment results were distributed to students, lecturers, and technicians before the next session. After the first session (T0) and at the end of all six sessions (T1), students completed a self-reported questionnaire. RESULTS: The mean wire-bending scores for FC were significantly higher than LD for two of the six assignments, namely the Adams clasp (p < 0.01) and Z-spring (p = 0.03). Scores for both LD and FC increased significantly over time, which may be attributed to formative assessment. There was no statistically significant correlation between wire-bending scores and video usage. Students were satisfied with both teaching methods, according to T0 and T1 questionnaires. CONCLUSIONS: Both LD and FC are equally effective in transferring practical orthodontic wire-bending skills and well-received by students. Continuous formative assessment may have enhanced students' learning of orthodontic wire-bending skills. Further studies with control group are recommended to investigate the effect of formative assessment on teaching practical dental skills.

In vitro Streptococcus mutans adhesion and biofilm formation on different esthetic orthodontic archwires.

OBJECTIVES: To evaluate the ability of different esthetic archwires to retain oral biofilms in vitro. MATERIALS AND METHODS: Seven different brands of coated orthodontic archwires were tested: two epoxy coated, two polytetrafluoroethylene coated, two rhodium coated, and one silver plus polymer coated. Conventional uncoated metallic archwires were used as controls. Streptococus mutans adherence to archwires was quantified by colony count following 24 hours of biolfilm growth, and total wire-associated biofilm was measured using a crystal violet staining assay. For both tests, two conditions were used: 0% sucrose and 3% sucrose. For statistical analysis, P < .05 was considered as statistically significant. RESULTS: For S. mutans colony forming units per biofilm, there were no statistically significant differences among the various archwires (P = .795 for 0% sucrose; P = .905 for 3% sucrose). Regarding total biofilm formed on archwires in the 3% sucrose condition, there were statistically significant differences in crystal violet staining only for the comparison between Niti Micro Dental White and Copper Ni-Ti wires (P < .05). CONCLUSIONS: The clinical use of esthetic-coated orthodontic wires may be considered to have similar risks as uncoated archwires for biofilm retention.

Evaluation of orthodontic loads and wire-bracket contact configurations in a three-bracket setup: Comparison of in-vitro experiments with numerical simulations.

So far, no practicable procedure exists to quantify the orthodontic loads applied to teeth in vivo. Dentists therefore rely on experience and simplified mechanical in-vitro experiments comprising deflection of orthodontic wires. Predicting the mechanical behaviour of orthodontic wires during clinical therapy requires understanding of the different contact states at multi-bracket-wire interfaces. This study experimentally investigates the effect of different bracket-wire contact configurations in a three-bracket setup and uses two numerical approaches to analyse and complement the experimental data. Commonly used round stainless-steel wires (diameter: 0.012″ and 0.016″) and titanium-molybdenum alloy wires (diameter: 0.016″ and 0.018″) were tested. All six force-moment components were measured separately for each of the three brackets. The results indicate that a specific sequence of distinct bracket-wire contact configurations occurs. Several transitions between configurations caused substantial changes of effective wire stiffness (EWS), which were consistent among experimental and numerical methods. The lowest EWS was observed for the configuration in which the wire touched only one wing of the lateral brackets. Taking this stiffness as 100%, the transition to a configuration in which the wire touched two opposing wings of the lateral brackets resulted in an increase of EWS of 300% ± 10%. This increase was independent of the wire type. Additional contacts resulted in further increases of stiffness beyond 400%. The results of this combined experimental and numerical study are important for providing a fundamental understanding of multi-bracket-wire contact configurations and have important implications for clinical therapy.

Novel approach for better compliance of mask during COVID pandemic.

COVID 19, started as a respiratory illness has affected the human life world-wide. Mandatory guidelines for wearing of masks have been issued by WHO even if you are stepping out. The continuous wearing of masks for prolonged duration has led to some negative consequences. MATERIAL AND METHOD: A new method was introduced to increase the compliance of mask by using easily available orthodontic wires in the dental set up. RESULTS: The new approach was helpful in getting rid of rashes, irritation and erythematous patches behind the ears along with the reduction in the chances of cross contamination. CONCLUSION: This method can be incorporated in routine in the dental practice, even when one is not working on the patient.

In vitro comparison of the torsional load transfer of various commercially available stainless-steel wires used for fixed retainers in orthodontics.

OBJECTIVE: To assess the torsional load transfer of various commercially available stainless-steel wires used for fixed retainers. DESIGN: An in vitro study using a robotic device. SETTING: Department of Pediatric Oral Health and Orthodontics, University of Basel. METHODS: A 10° proclination of a maxillary lateral incisor of a 2-2 retainer was simulated with a robotic device. Eight stainless-steel wires with different shapes (round or rectangular), types (plain, braided, coaxial or chain) and dimensions were selected to measure the torsional load transfer at the adjacent central incisor. The influence of annealing was also tested. RESULTS: The 0.016 × 0.016 and Bond-A-Braid™ wires (0.02645 × 0.01055-inch, 8-stranded, braided) showed the largest relative torsional load transfer (3.7% and 3.3%, respectively). The two multistranded wires - Triple Flex™ and Respond® - showed the smallest values of 1.0% and 0.7%, respectively. The spiral direction of these two multistranded wires affected the load transfer, the twisting showing larger torsional load transfer than the untwisting one. CONCLUSION: The effective torsional load transfer depends on the dimension, shape and type of a wire. Plain and braided retainers were more predictable in torsional load transfer than multistranded retainers, which may have stored more energy in the area between the composite bonding sites. This may explain the unexpected complications reported in multistranded retainers.

Effects of TiO2-Coated Stainless Steel Orthodontic Wires on Streptococcus mutans Bacteria: A Clinical Study.

INTRODUCTION: The aim of this study was to clinically evaluate Streptococcus mutans adhesion on titanium dioxide-coated stainless steel orthodontic wires to decrease white-spot formation. METHODS: In this study, four groups of 17 patients each (n=68) aged 12-25 years participated. A titanium dioxide coating layer was deposited on 0.4572 mm stainless steel orthodontic wires using physical vapor deposition. The coated wires were randomly assigned to one jaw, and the opposite jaw received an uncoated wire as control. Patients were divided into groups according to the duration that wires were in their mouths: A) 1 week, B) 2 weeks, C) 3 weeks, and D) 4 weeks. Block randomization was used to assign patients to each group. At the end of the experiment, 20 mm of each wire (canine-to-canine area) was cut and cultured in S. mutans-specific medium. The culture plates were placed in an incubator containing 5% CO2 for 72 hours at 37°C, and then colonies were counted. MTT was used to test the biocompatibility of the coated and uncoated wires. To evaluate the stability of the coated titanium dioxide layer on the wires, titanium concentration on the saliva was determined using inductively coupled plasma mass spectroscopy. RESULTS: The Kruskal-Wallis test showed that there was no significant difference in colony counts among the coated wires during 1-4 weeks (p<0.48). In the uncoated-wire groups, colonys count at week 1 were higher than weeks 24 -(p<0.022). Wilcoxon's test showed that the number of colonies was significantly different in groups A and C, but there was no significant difference in groups B or D. MTT-assay results showed that there was not a significant difference between cell viability in the coated-wire group and the control. The Kruskal-Wallis test showed that there was no significant difference in titanium concentration in the studied groups (p<0.834). CONCLUSION: Application of titanium dioxide coating is effective in reducing bacterial adhesion at wire insertion.

The Effect of Live-Video Demonstration on Dental Students' Orthodontic Bending Performance.

The aims of this study were to evaluate the effects of a live-video teaching tool on the performance of dental students in bending an orthodontic vestibular arch and to assess the students' perceptions of the technology. All 135 fourth-year dental students in the 2018 academic year at Hacettepe Dental School, Ankara, Turkey, were invited to participate in the study; after exclusions, the remaining 116 were randomly divided into two demonstration cohorts. These students had no prior experience bending an orthodontic wire. Cohort 1 (control, N=58) was shown a conventional live demonstration of the orthodontic bending of a vestibular arch, and Cohort 2 (experimental, N=58) was shown a live-video demonstration of the same procedure. Both cohorts saw the demonstration before beginning the exercise and were evaluated afterwards on their performance of the procedure. In addition, the students' perceptions of the demonstration techniques were collected with a questionnaire. The results did not show any significant differences in the students' bending scores between the control and experimental cohorts (p=0.767). The median values on the questionnaire indicated almost no statistically significant difference in responses between the cohorts. The only significant difference was that Cohort 1 had a higher percentage who answered "yes" they would like to rewatch the demonstration than did Cohort 2 (p=0.024). In this study, the live-video technique was found to be as effective as a conventional live demonstration for orthodontic practical education, suggesting that either technique could be used as an appropriate method for training in orthodontic wire bending.