An in vitro comparative evaluation of surface roughness characteristics of different orthodontic archwires: An atomic force microscopy study

Comparing the efficacy of heat-activated NiTi (HANT) versus conventional NiTi archwires: A systematic review and meta-analysis

OBJECTIVE

To assess the effectiveness of heat-activated NiTi (HANT) wires compared to NiTi wires during orthodontic alignment, through a systematic review and meta-analysis.

SEARCH METHODS

We comprehensively searched databases up to January 2024, including MEDLINE, Web of Science, EMBASE, Scopus, and Cochrane's CENTRAL, without language or date restrictions.

SELECTION CRITERIA

Clinical studies aligning with the PICO question were included, and their bias risk was evaluated using the Cochrane Risk of Bias 2.0 tool.

DATA COLLECTION AND ANALYSIS

Data were collected using custom forms, and a meta-analysis was performed using random-effects inverse variance. Primary outcome was Little's Irregularity Index (LII) changes. Secondary outcomes were pain intensity and root resorption.

RESULTS

Thirteen clinical studies were reviewed, with nine included in the meta-analysis. No significant differences were observed in LII changes during the first four months, with similar findings in the first, second and third months. In the fourth month, NiTi wires exhibited higher reductions. Pain intensity did not differ between groups on the first or the seventh day. No significant difference in root resorption was found between the two groups.

CONCLUSIONS

HANT and conventional NiTi wires showed comparable effectiveness in reducing LII, pain levels, and root resorption during the orthodontic alignment phase. While HANT wires may entail higher costs, their ease of insertion and ligation offer practical advantages. Ultimately, choosing between wire types should consider individual patient needs and clinician preferences.

Assessment of Various Archwire Materials and Their Impact on Orthodontic Treatment Outcomes

Aim Orthodontic treatment relies heavily on the mechanical properties and surface characteristics of archwire materials to achieve optimal outcomes. This study aimed to comprehensively evaluate the mechanical properties, including tensile strength, yield strength, and modulus of elasticity, as well as the surface characteristics, such as surface roughness and frictional properties, of different archwire materials. Methods Four types of archwire materials, stainless steel, nickel-titanium (NiTi), beta-titanium, and esthetic archwires, were subjected to mechanical testing and surface analysis, with 31 in each group. Tensile testing was conducted to determine the maximum tensile strength, yield strength, and elastic modulus of each material. Surface roughness analysis was performed using profilometry techniques, and frictional properties were evaluated using an orthodontic friction testing apparatus. Results Stainless steel exhibited the highest tensile strength (900 N), followed by beta-titanium (850 N), NiTi (800 N), and esthetic archwire (750 N). Stainless steel also demonstrated the highest yield strength (780 N), followed by beta-titanium (740 N), NiTi (710 N), and esthetic archwire (650 N). The modulus of elasticity was the highest for stainless steel (200 GPa), followed by beta-titanium (170 GPa), NiTi (150 GPa), and esthetic archwires (120 GPa). Surface roughness was lowest in stainless steel archwires (mean Ra value of 0.25 µm), leading to reduced frictional resistance, whereas esthetic archwires exhibited the highest surface roughness (mean Ra value of 0.40 µm) and frictional forces. Significant differences in the mechanical properties and surface characteristics were observed among the materials (p < 0.05). Conclusions The choice of archwire material significantly influences orthodontic treatment outcomes by affecting the efficiency and effectiveness of tooth movement. Stainless steel and beta-titanium wires are ideal for high-stress applications, providing the robust mechanical strength necessary for complex movements. In contrast, NiTi wires, with their superelasticity, offer consistent and gentle forces, enhancing patient comfort and accelerating the alignment phase. Esthetic archwires, while visually appealing, often compromise mechanical performance, potentially prolonging treatment duration.

Comparison of Surface Roughness of Different Orthodontic Archwires: Atomic Force Microscopic Study

BACKGROUND

Surface roughness (SR) of dental components is significant because it impacts the surface area of the contact surface, which in turn affects corrosion behavior and biological compatibility. Orthodontic archwires (OA) with SR can affect the coefficient of friction, which in turn affects how effectively sliding biomechanics work and how the orthodontic appliance works efficiently.

AIM

The objectives of the present investigation were to examine the SR of five distinct kinds of OA using an atomic force microscope (AFM) and to assess the merits of using AFM to analyze orthodontic materials.

METHODS

For this investigation, there were five distinct orthodontic archwires with rectangular cross-sectional geometry. There were assigned different categories: Category 1: SmartArch wires (Ormco) (n=20), Category 2: Damon wires (Ormco) (n=20), Category 3: heat-activated nickel-titanium (HANT) wires (G&H Orthodontics) (n=20), Category 4: nickel-titanium (NiTi) wires (G&H Orthodontics) (n=20), Category 5: stainless steel (SS) wires (Ormco) (n=20). Each wire category's 20 samples were selected. Ten samples from each category had 5 mm of wire clipped from the finish point of the archwires. These were observed using the AFM in natural lighting. Using a cyanoacrylate glue that dries quickly, the samples were fastened to a metal holder. Ten randomly chosen patches of the surface, each measuring 15 × 15 µm, were taken from every sample and examined (N = 500).

RESULTS

The mean values of roughness average (Ra) in category 1, category 2, category 3, category 4 and category 5 were 23.08 ± 17.66, 26.78 ± 5.65, 26.66 ± 3.89, 9.71 ± 0.29 and 11.29 ± 2.12 respectively. The values of Ra representing SR were greatest in category 3 (HANT wires) followed by category 2 (Damon wires) while values of SR were minimum in category 4 (NiTi wires) and category 5 (stainless steel wires). The findings had statistical significance also.

CONCLUSION

The SR of stainless steel wire was discovered to be less than that of the other wires. The SR may have an impact on the efficiency of sliding mechanics as well as the appeal and corrosion resistance of orthodontic components.

A digital orthodontic arch wire design system with interactive adjustment and intelligent optimization

The design of orthodontic arch wires is a prerequisite for orthodontic treatment that determines the subsequent orthodontic effects. Current methods for designing orthodontic arch wires are often based on traditional manual techniques, which suffer from problems such as low accuracy and efficiency. To address these issues, a digital orthodontic arch wire design system has been developed using Unity 3D and C#. This system allows for the interactive adjustment and intelligent optimization of the shape of digital orthodontic arch wires. The developed system includes modules for curve design, contour construction, and collision detection of orthodontic arch wires, which can be customized interactively to meet the personalized needs of patients. In addition, an energy-constrained method is employed to optimize the shape of certain regions of the arch wire, which helps overcome distortion and interference issues caused by unreasonable interaction. The effectiveness of the developed system has been evaluated through experiments on digital design and optimization of orthodontic arch wires. Results demonstrate that the system can achieve accurate and efficient digital design of orthodontic arch wires, effectively reduce distortion, and is expected to improve the orthodontic effect.

Assessment of the influence of metal ions released from the fixed orthodontic appliances on the static friction and surface topography of stainless steel and I archwires: An in-vitro study

BACKGROUND

Static friction force between the orthodontic brackets and wire impacts the sliding mechanics that affect teeth movements and treatment duration. This sliding media is jam-packed with released metal ions from the fixed appliances. This study aimed to assess the static frictional force and surface topography of stainless steel (SS) and I archwires in dry conditions and in media fully with metal ions that were released from fixed appliances.

METHODS

In this research study, a set of 60 as-received straight archwires specimens (5 cm wire) were employed and categorized into two groups based on the material type [30 super elastics new I archwires gauge (0.018 × 0.014 inch) and 30 SS archwires 0.018 × 0.022" as a control]. The archwires' static friction force was measured while sliding a loaded Roth SS brackets (0.018") on the archwire using a universal tensile testing machine in dry and metal ions released media, while the surface topography was assessed using a noncontact AFM machine.

RESULTS

The static friction of I archwire was significantly lower than the SS wire in dry condition. Metal ions media released from fixed appliances significantly reduced the Static friction compared to dry and wet conditions with deionized water for both wires. An Atomic Force Microscope machine surface roughness reports revealed that the highest mean of all three roughness parameters was found in the SS group, followed by I archwires in descending order. Additionally, metal ions media significantly reduce all roughness parameters.