Assessment of the Mechanical Properties of Three Commercially Available Thermoplastic Aligner Materials used for Orthodontic Treatment

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Alok Ranjan ◽  
Anil Kumar Biradar ◽  
Ankita Patel ◽  
Vanessa Varghese ◽  
Ankita Pawar ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Yield Strength ◽  
Tooth Movement ◽  
Testing Machine ◽  
Bending Test ◽  
P Value ◽  
Stress Release ◽  
Relaxation Properties ◽  
Intergroup Comparison ◽  
Materials Used

Objectives: This studied aimed to measure the yield strength and stress relaxation properties of three commercially available thermoplastic aligner materials. Methods: The three different thermoplastics aligner materials Duran (Scheu, Iserlohn, Germany), Erkodur (Pfalzgrafenweiler, Erkodent, Germany) and Track (Forestadent, Germany) were selected. A three-point bending test was carried out via the universal testing machine to measure their yield strength and stress relaxation properties. An independent t- test was performed for intergroup comparison. P-value < 0.05 was set as the level of significance. Results: All the selected three polymers liberate a notable amount of stress during 24 hours. The highest stress release was observed in Duran i.e. 18.96 N/cm2 as compared to Erkodur, which was 13.96 N/cm2 and Track, which was 13.18 N/cm2. The yield strength of Duran was the highest (75.85 Mpa) compared to Track and Erkodur with the yield strength of 52.75 Mpa and 55.86 Mpa, respectively. Conclusions: Tooth movement is influenced by the composition of aligner material and its thickness. Duran had the highest stress release and yield strength. Stress released by different aligners exceeds around half of the initial stress value, which directly affects the orthodontic force application and subsequent tooth movement.

scholarly journals Utilization of Recycled Thermoplastic Nylon Combined with Virgin Nylon and the Effect on its Mechanical Properties as a Denture Base Material

2019 ◽  
pp. 51-55
Author(s):  
Haslinda Z Tamin ◽  
Siti Wahyuni ◽  
Ismet Danial Nasution
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Modulus Of Elasticity ◽  
Statistical Significance ◽  
Testing Machine ◽  
Base Material ◽  
Bending Test ◽  
Laboratory Research ◽  
Compressive Yield Strength ◽  
Mechanical Degradation

The injection molding process of thermoplastic nylon produces nylon residues in the form of sprue. Nylon residues are non-biodegradable which causes serious ecological problems, hence recycling becomes a necessity. However, recycled nylon is subjected to thermal, oxidative, and mechanical degradation during process which may decrease the mechanical properties of recycled nylon. In order to overcome the decreased mechanical properties of recycled nylon, modification by combining recycled nylon with virgin nylon is considered. Aim: This study aimed to determine the effect of adding virgin nylon into recycled nylon on the modulus of elasticity and compressive yield strength. Settings and Design: Experimental laboratory research. Methods and Materials: A total of 45 samples were used. Samples were divided into 3 groups which include 100% virgin nylon as control (A), 100% recycled nylon (B) and combination of 60% virgin nylon with 40% recycled nylon (C). The samples were tested using Universal Testing Machine (Tensilon RTF, Japan) with three point bending test and compression test with the speed of 5mm/min with ultimate load. Statistical analysis used: The obtained results were analyzed using Univarian test, One-way ANOVA test and Turkey’s Honestly Significant Different test. Result: There was statistical significance in adding virgin nylon into recycled nylon on its mechanical properties, namely modulus of elasticity and compressive yield strength (p<0.05). Conclusion: The combination of 60% virgin nylon with 40% recycled nylon has better elastic modulus and compressive yield strength values compared to 100% recycled nylon.

scholarly journals In vitro force delivery of nickel-titanium superelastic archwires in vertical displacement

2012 ◽  
Vol 17 (6) ◽  
pp. 26-30
Author(s):  
Aisha de Souza Gomes Stumpf ◽  
Karina dos Santos Mundstock ◽  
Daniel Mundstock ◽  
Carlos Alberto Mundstock
Keyword(s):  
Tooth Movement ◽  
Testing Machine ◽  
Rocky Mountain ◽  
Vertical Displacement ◽  
Nickel Titanium ◽  
Stress Release ◽  
Maximum Displacement ◽  
Universal Testing ◽  
Temperature Controlled

OBJECTIVE: The purpose of this study was to evaluate the force delivered by different superlastic nickel-titanium wires during vertical displacement, in order to determine whether their stress release meets the criteria for constant and light forces that are usually accredited to these archwires. METHOD: Ten samples of 6 brands of 0.016-in archwires (Ormco, GAC, Morelli, TP, American Orthodontics e Rocky Mountain) were tested in a complete metal model using Dynalock brackets (3M Unitek™). In the canine position, there was a sliding bracket connected to a pole. This set was related to a load cell of 0.5 kg attached to a universal testing machine (Autograph AG-199kNG, Shimadzu). The crosshead speed was 0.5 mm/min and the maximum displacement was 1.0 mm. The model was submerged in temperature-controlled water. The results were analyzed by ANOVA (p < 0.05), using the software SAS System 8.02, Cry, NC, USA. RESULTS: The TP archwire had the lowest force throughout the test, although the final force was high (277.91 g). The Rocky Mountain archwire had the highest force release (455.41 g). CONCLUSION: The different brands of wires tested in this study failed in delivering low and constant forces as expected from superlastic nickel-titanium wires. The forces were extremely heavy for a vertical tooth movement.

scholarly journals Stress relaxation properties of four orthodontic aligner materials: A 24-hour in vitro study

2016 ◽  
Vol 87 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Luca Lombardo ◽  
Elisa Martines ◽  
Valentina Mazzanti ◽  
Angela Arreghini ◽  
Francesco Mollica ◽  
...  
Keyword(s):  
Tooth Movement ◽  
Single Layer ◽  
In Vitro Study ◽  
Constant Load ◽  
Strength Testing ◽  
Stress Release ◽  
Materials Used ◽  
F22 Aligner ◽  
Over Time

ABSTRACT Objective: To investigate the stress release properties of four thermoplastic materials used to make orthodontic aligners when subjected to 24 consecutive hours of deflection. Materials and Methods: Four types of aligner materials (two single and two double layered) were selected. After initial yield strength testing to characterize the materials, each sample was subjected to a constant load for 24 hours in a moist, temperature-regulated environment, and the stress release over time was measured. The test was performed three times on each type of material. Results: All polymers analyzed released a significant amount of stress during the 24-hour period. Stress release was greater during the first 8 hours, reaching a plateau that generally remained constant. The single-layer materials, F22 Aligner polyurethane (Sweden & Martina, Due Carrare, Padova, Italy) and Duran polyethylene terephthalate glycol-modified (SCHEU, Iserlohn, Germany), exhibited the greatest values for both absolute stress and stress decay speed. The double-layer materials, Erkoloc-Pro (Erkodent, Pfalzgrafenweiler, Germany) and Durasoft (SCHEU), exhibited very constant stress release, but at absolute values up to four times lower than the single-layer samples tested. Conclusions: Orthodontic aligner performance is strongly influenced by the material of their construction. Stress release, which may exceed 50% of the initial stress value in the early hours of wear, may cause significant changes in the behavior of the polymers at 24 hours from the application of orthodontic loads, which may influence programmed tooth movement.

scholarly journals Surface Properties of Polymer Resins Fabricated with Subtractive and Additive Manufacturing Techniques

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4077
Author(s):  
Amal S. Al-Qahtani ◽  
Huda I. Tulbah ◽  
Mashael Binhasan ◽  
Maria S. Abbasi ◽  
Naseer Ahmed ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Flexural Strength ◽  
Testing Machine ◽  
Study Groups ◽  
Bending Test ◽  
P Value ◽  
Micro Hardness ◽  
Significant Difference ◽  
Cad Cam ◽  
Manufacturing Techniques

This study aimed to compare the surface roughness, hardness, and flexure strength of interim indirect resin restorations fabricated with CAD-CAM (CC), 3D printing (3D), and conventional techniques (CV). Twenty disk (3 mm × Ø10 mm) and ten bar specimens (25 × 2 × 2 mm) were fabricated for the CC, 3D, and CV groups, to be used for surface roughness, micro-hardness, and flexural strength testing using standardized protocol. Three indentations for Vickers micro-hardness (VHN) were performed on each disk and an average was identified for each specimen. Surface micro-roughness (Ra) was calculated in micrometers (μm) using a 3D optical non-contact surface microscope. A three-point bending test with a universal testing machine was utilized for assessing flexural strength. The load was applied at a crosshead speed of 3 mm/min over a distance of 25 mm until fracture. Means and standard deviations were compared using ANOVA and post hoc Tukey–Kramer tests, and a p-value of ≤0.05 was considered statistically significant. Ra was significantly different among the study groups (p < 0.05). Surface roughness among the CC and CV groups was statistically comparable (p > 0.05). However, 3D showed significantly higher Ra compared to CC and CV samples (p < 0.05). Micro-hardness was significantly higher in 3D samples (p < 0.05) compared to CC and CV specimens. In addition, CC and CV showed comparable micro-hardness (p > 0.05). A significant difference in flexural strength was observed among the study groups (p < 0.05). CC and 3D showed comparable strength outcomes (p > 0.05), although CV specimens showed significantly lower (p < 0.05) strength compared to CC and 3D samples. The 3D-printed provisional restorative resins showed flexural strength and micro-hardness comparable to CAD-CAM fabricated specimens, and surface micro-roughness for printed specimens was considerably higher compared to CAD-CAM and conventional fabrication techniques.

Comparison of Loading and Unloading Behavior of Commercial and Locally Made Copper-Nickle-Titanium (NiTiCu) Orthodontic Archwire

2013 ◽  
Vol 746 ◽  
pp. 308-314
Author(s):  
V. Puranitee ◽  
Surachai Dechkunakorn ◽  
N. Anuwongnukroh ◽  
A. Khantachawana ◽  
A. Phukaoluan
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Testing Machine ◽  
Bending Test ◽  
Stress Plateau ◽  
Percentage Recovery ◽  
Significant Difference ◽  
Loading And Unloading ◽  
Materials Used ◽  
Stress Hysteresis

Background: Copper-nickel-titanium (NiTiCu) archwire has been favoured in clinical orthodontic practice because of its superior superelasticity (SE) and shape memory effect (SME) properties. Objective: To compare the loading and unloading behavior of commercial NiTiCu orthodontic archwire and locally made NiTiCu orthodontic archwire based on composition and mechanical properties especially in relation to percentage recovery, stress plateau, stress hysteresis, and loading and unloading slope. Materials and Methods: The materials used were divided into two categories: the NiTiCu (40°C) commercial Ormco brand (USA) archwires and the locally made NiTiCu archwires produced at King Mongkut University of Technology Thonburi (KMUTT). The samples were examined using an Electron Probe Microanalysis (EPMA) to test their chemical composition. For loading and unloading behavior the Universal Testing Machine (Instron) was used for the three-point bending test. The Mann-Whitney U test was employed to analyze and compare the data. Results: Chemical composition, there were significant differences in at.% of Ni, Ti, and Cr composition between commercial and locally made archwire. There was no significant difference in at.% in Cu. In terms of percentage recovery, there was a significant decrease in locally made archwire. For stress plateau and stress hysteresis, there were also significant increases in Thai-made archwire when compared with commercial archwires. In addition NiTiCu (Ormco) showed significantly less inclination than locally made NiTiCu archwire in both loading and unloading slopes. Conclusion: Based on the results of this study, the mechanical properties of the locally made archwires were not as suitable as the commercial archwires. This preliminary study provides useful information for the further development of locally made NiTiCu archwires. Therefore, the use of the NiTiCu should be considered on a case by case basis. This experiment was useful in comparing locally made NiTiCu wire and commercial orthodontic wire.

scholarly journals Comparative Evaluation of Frictional forces between different Archwire-bracket Combinations

2014 ◽  
Vol 4 (1) ◽  
pp. 22-28 ◽  
Author(s):  
Vinit Singh ◽  
Swati Acharya ◽  
Satyabrata Patnaik ◽  
Smruti Bhusan Nanda
Keyword(s):  
Stainless Steel ◽  
Tooth Movement ◽  
Testing Machine ◽  
Frictional Resistance ◽  
Nickel Titanium ◽  
Orthodontic Bracket ◽  
Fixed Appliance ◽  
Beta Titanium ◽  
Frictional Forces

Introduction: During sliding mechanics, frictional resistance is an important counterforce to orthodontic tooth movement; whichmust be controlled to allow application of light continuous forces.Objective: To investigate static and kinetic frictional resistance between three orthodontic brackets: ceramic, self-ligating, andstainless steel, and three 0.019×0.025” archwires: stainless steel, nickel-titanium, titanium-molybdenum.Materials & Method: The in vitro study compared the effects of stainless steel, nickel-titanium, and beta-titanium archwires onfrictional forces of three orthodontic bracket systems: ceramic, self-ligating, and stainless steel brackets. All brackets had 0.022”slots, and the wires were 0.019×0.025”. Friction was evaluated in a simulated half-arch fixed appliance on a testing machine. Thestatic and kinetic friction data were analyzed with 1-way analysis of variance (ANOVA) and post-hoc Duncan multiple rangetest.Result: Self-ligating (Damon) brackets generated significantly lower static and kinetic frictional forces than stainless steel (Gemini)and ceramic brackets (Clarity). Among the archwire materials, Beta-titanium showed the maximum amount of frictional forceand stainless steel archwires had the lowest frictional force.Conclusion: The static and kinetic frictional force for stainless steel bracket was lowest in every combination of wire.

scholarly journals Fracture Load of Metal, Zirconia and Polyetheretherketone Posterior CAD-CAM Milled Fixed Partial Denture Frameworks

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 959
Author(s):  
Verónica Rodríguez ◽  
Celia Tobar ◽  
Carlos López-Suárez ◽  
Jesús Peláez ◽  
María J. Suárez
Keyword(s):  
Computer Aided Design ◽  
Testing Machine ◽  
Fracture Load ◽  
Fracture Pattern ◽  
Bending Test ◽  
Weibull Statistics ◽  
Promising Alternative ◽  
Computer Aided ◽  
Cad Cam ◽  
Group 2

The aim of this study was to investigate the load to fracture and fracture pattern of prosthetic frameworks for tooth-supported fixed partial dentures (FPDs) fabricated with different subtractive computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: Thirty standardized specimens with two abutments were fabricated to receive three-unit posterior FDP frameworks with an intermediate pontic. Specimens were randomly divided into three groups (n = 10 each) according to the material: group 1 (MM)—milled metal; group 2 (L)—zirconia; and group 3 (P)—Polyetheretherketone (PEEK). The specimens were thermo-cycled and subjected to a three-point bending test until fracture using a universal testing machine (cross-head speed: 1 mm/min). Axial compressive loads were applied at the central fossa of the pontics. Data analysis was made using one-way analysis of variance, Tamhane post hoc test, and Weibull statistics (α = 0.05). Results: Significant differences were observed among the groups for the fracture load (p < 0.0001). MM frameworks showed the highest fracture load values. The PEEK group registered higher fracture load values than zirconia samples. The Weibull statistics corroborated these results. The fracture pattern was different among the groups. Conclusions: Milled metal provided the highest fracture load values, followed by PEEK, and zirconia. However, all tested groups demonstrated clinically acceptable fracture load values higher than 1000 N. PEEK might be considered a promising alternative for posterior FPDs.

Gigacycle Fatigue of Welded Joints of Structural Materials (A Review)

2016 ◽  
Vol 17 ◽  
pp. 14-30 ◽  
Author(s):  
Okechukwu P. Nwachukwu ◽  
Alexander V. Gridasov ◽  
Ekaterina A. Gridasova
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Structural Materials ◽  
Fatigue Tests ◽  
Material Defects ◽  
Graphite Cast Iron ◽  
Ultrasonic Fatigue ◽  
Materials Used ◽  
Fatigue Failures

This review looks into the state of gigacycle fatigue behavior of some structural materials used in engineering works. Particular attention is given to the use of ultrasonic fatigue testing machine (USF-2000) due to its important role in conducting gigacycle fatigue tests. Gigacycle fatigue behavior of most materials used for very long life engineering applications is reviewed.Gigacycle fatigue behavior of magnesium alloys, aluminum alloys, titanium alloys, spheroid graphite cast iron, steels and nickel alloys are reviewed together with the examination of the most common material defects that initiate gigacycle fatigue failures in these materials. In addition, the stage-by-stage fatigue crack developments in the gigacycle regime are reviewed. This review is concluded by suggesting the directions for future works in gigacycle fatigue.

An Investigation of Adaptive Rubber Bearings

2016 ◽  
Author(s):  
C. S. Tsai ◽  
Hui-Chen Su ◽  
Wen-Chun Huang
Keyword(s):  
Yield Strength ◽  
Lower Yield ◽  
Passive Devices ◽  
Major Benefit ◽  
Lead Rubber Bearings ◽  
Lower Yield Strength ◽  
Multiple Levels ◽  
Materials Used ◽  
Rubber Bearings ◽  
Stiffness And Damping

Proposed in this study are several innovative seismic isolators composed of rubber materials that are called adaptive rubber bearings based on their adaptive characteristics. The materials used in the proposed isolators are free of lead commonly found in lead rubber bearings. The lead material results in a heavy environmental burden as well as lower yield strength and damping due to rising temperature during earthquakes, and thus causes larger displacements than we would expect. The designed mechanisms in the proposed isolators enable these devices to be manufactured relatively easily. They also provide extremely high damping to bearings, which is strongly desired by engineers in practice. The proposed rubber bearings are completely passive devices yet possess adaptive stiffness and adaptive high damping. The change in stiffness and damping is predictable and can be calculated at specifiable and controllable displacement amplitudes. The major benefit of the adaptive characteristics of seismic isolators is that a given system can be optimized separately for multiple performance objects at multiple levels of earthquakes. In this study, mathematical formulations are derived to explain the mechanisms of the proposed devices. Experimental results of high velocity cyclical loadings are also provided to verify the advanced concepts of the proposed devices.

Sign in / Sign up

Export Citation Format

Share Document