Differences in Orthodontic Thermal Deflection of Nickel Titanium Wire in Artificial Saliva Soat And Isotonic Beverages

The purpose of this study was to investigate the changes in the load deflection of nickel titanium orthodontic wire after different recycling protocols. A spooled 0.014 inch nickel titanium wire was separated into 7 groups: as received condition (T0,control group),treated in artificial saliva for 4 weeks (T1), treated in artificial saliva and autoclaved (T2), treated in artificial saliva and dry heated (T3), treated in artificial saliva and disinfected by glutaraldehyde (T4), treated in artificial saliva and disinfected by iodophor (T5) and treated in artificial saliva and disinfected by chlorhexidine (T6).The changes in the load deflection were observed by special test apparatus based on 3-point bending mechanism, the findings of the current study showed that there was highly significant difference in mean load deflection of nickel titanium wire between all recycling protocols (P< 0.0001). The recycling by sterilization of the wire by heat autoclave or disinfection by chlorhexidine both seem to be the best recycling protocols because of lowest detrimental effect on the load deflection, while the disinfection by glutaraldehyde or iodophor shows intermediate detrimental effect on the load deflection, and the sterilization by dry heat seems to be the worst recycling protocol because it shows highest detrimental effect on the load deflection value.

Background: Composite resins are dental restorative materials that are widely used and have high aesthetic value compared to other materials. However, acidic environmental conditions can degrade the composite resins, resulting in increased surface roughness of the resin, and consequently lead to an increased risk of caries.Objective: the purpose of this study was to evaluate the effect of immersion in acidic drinks on the surface roughness of composite resins,Method: In this study 24 samples of bulk fillTM composite resins were used. Samples were divided into four groups. Each sample was immersed for 5 seconds in either artificial saliva (control), carbonated beverage, isotonic, or yogurt, and followed by 5 seconds immersion in saliva. This cycle was repeated for 20 times for 14 consecutive days. The roughness of composite resin before and after 14 days immersion was measured by using a profilometer. Microscopic structures were analyzed by Scanning electron Microscope (SEM). Statistical analysis was used paired t-test, Anova and Post Hoc LSD.Results: Data from each sample group was normally distributed- with p > 0.05. The paired t-test for each group showed a p-value < 0.05, which indicates there was a significant difference between surface roughness before and after immersion. ANOVA analysis revealed that there was a difference in the surface roughness between groups LSD test, showed that there was difference in the surface roughness between artificial saliva with carbonated drink, isotonic drink with carbonated drink, yoghurt drink with carbonated drink (p<0.0001), between artificial saliva group with yoghurt drink, yoghurt drink with carbonated drink, yoghurt drink with isotonic drink (p <0.05) which means there was a significant difference between group. Meanwhile, the isotonic drinks with artificial saliva obtained results (p>0.05), which means there is no significant difference.Conclusion: Exposure of carbonated drinks, yoghurt drinks, and isotonic drinks can significantly increase the roughness of the surface Bulk Fill resin composite compared to exposure of artificial saliva.Keywords: Composite resin, Bulk Fill, Surface Roughness, Acid

BackgroundThis study aimed to compare superelastic and heat-activated nickel-titanium orthodontic wires’ surface morphology and potential release of nickel ions following exposure to oral environment conditions.MethodsTwenty-four 20-mm-length distal cuts of superelastic (NiTi Force I®) and 24 20-mm-length distal cuts of heat-activated (Therma-Ti Lite®) nickel-titanium wires (American Orthodontics, Sheboygan, WI, USA) were divided into two equal groups: 12 wire segments left unused and 12 segments passively exposed to oral environment for 1 month. Scanning electron microscopy and atomic force microscopy were used to analyze surface morphology of the wires which were then immersed in artificial saliva for 1 month to determine potential nickel ions’ release by means of atomic absorption spectrophotometer.ResultsHeat-activated nickel-titanium (NiTi) wires were rougher than superelastic wires, and both types of wires released almost the same amount of Ni ions. After clinical exposure, more surface roughness was recorded for superelastic NiTi wires and heat-activated NiTi wires. However, retrieved superelastic NiTi wires released less Ni ions in artificial saliva after clinical exposure, and the same result was recorded regarding heat-activated wires.ConclusionsBoth types of NiTi wires were obviously affected by oral environment conditions; their surface roughness significantly increased while the amount of the released Ni ions significantly declined.

Residents' journal review

Orthodontic wires containing nickel have been implicated in allergic reactions. The potential for orthodontic wires to cause allergic reactions is related to the pattern and mode of corrosion with subsequent release of metal ions, such as nickel, into the oral cavity. The purpose of this study was to determine if there is a significant difference in the corrosive potential of stainless steel, nickel titanium, nitride-coated nickel titanium, epoxy-coated nickel titanium, and titanium orthodontic wires. At least two specimens of each wire were subjected to potentiostatic anodic dissolution in 0.9% NaCl solution with neutral pH at room temperature. Using a Wenking MP 95 potentiostat and an electrochemical corrosion cell, the breakdown potential of each wire was determined. Photographs were taken of the wire speci mens using a scanning electron microscope, and surface changes were qualitatively evaluated. The breakdown potentials of stainless steel, two nickel titanium wires, nitride-coated nickel titanium, epoxy-coated nickel titanium, and titanium were 400 mV, 300 mV, 750 mV, 300 mV, 1800 mV, and >2000 mV, respectively. SEM photographs revealed that some nickel titanium and stainless steel wires were susceptible to pitting and localized corrosion. The results indicate that corrosion occurred readily in stainless steel. Variability in breakdown potential of nickel titanium alloy wires differed across vendors' wires. The nitride coating did not affect the corrosion of the alloy, but epoxy coating decreased corrosion. Titanium wires and epoxy-coated nickel titanium wires exhibited the least corrosive potential. For patients allergic to nickel, the use of titanium or epoxy-coated wires during orthodontic treatment is recommended.

This in vitro study aimed to investigate the color changes of the bracket-bonded tooth surfaces after the use of 4 different mouthwashes. A total of 100 human premolar teeth were randomly divided into 10 equal groups. Color values (L*a*b*) of the buccal surfaces of each tooth were assessed using a digital spectrophotometer. Then the brackets were bonded. The groups were put either in sterile saline (4 test+1 control) or artificial saliva (4 test+1 control) solutions, and test groups were immersed in their mouthwashes (Colgate Plax, Listerine Cool Mint, Klorhex, and Tantum Verde) for 1min each in the morning/evening to simulate the mouth washing for 21days after the bonding. After the debonding and finishing procedures, final color measurements were performed. Color changes (∆E) were calculated. All of the parameters showed statistically significant differences among the groups. The least noticeable color changes were detected in the control groups. The most noticeable color change (ΔE) was observed in the Tantum Verde + artificial saliva group, followed by Tantum Verde + sterile saline and Klorhex + artificial saliva groups, all of which were significantly higher than the control groups. The use of mouthwashes during orthodontic treatment may cause noticeable changes in tooth color. Listerine Cool Mint may be the choice of mouthwash with its less discoloring effects. Artificial saliva should be preferred in similar in vitro studies to reflect the oral environment better. Mouthwash use during orthodontic treatment may result in different levels of enamel discoloration.

The development of technology in orthodontic field produces some orthodontic wires that have different deflection abilities. Loading force is the force needed to place an orthodontic wire in bracket slot (activation). Unloading force is the force produced by an orthodontic wire to move tooth (deactivation). Deflection test with three-point bending technique is a technique that is often used to determine the magnitude of the activation and deactivation force of orthodontic wire. Stainless steel (SS), nickel titanium (NiTi), copper nickel titanium (CuNiTi), and beta titanium (TMA), are the types of frequently used wires. This study aimed to compare loading and unloading force on the deflection test of SS, NiTi, CuNiTi, and TMA orthodontic wires sized 0.016 x 0.022 inch on the load-deflection graph. This is a laboratoryexperimental research on a total of 16 pieces of SS, NiTi, CuNiTi, and TMA orthodontic wires sized 0.016 x 0.022 inches. The group was divided based on the type of material. The deflection test was performed using a universal testing machine with a press speed of 5 mm/minute. Loading and unloading forces were recorded on deflections of 0.5; 1; and1.5 mm. Statistical tests of differences among groups were carried out by ANOVA analysis (p-value ≤ 0.05) and post-hoc analysis with T-test. There were significant differences in the loading and unloading forces recorded on deflections of 0.5; 1; and 1.5 mm; except for deflections of 0.5 mm of the SS and nickel-titanium wires. The wire deflection force fromthe lowest to the highest was CuNiTi wire, nickel-titanium wire, TMA wire, and stainless-steel wire.

Superelastic NiTi wires probably produce slightly more pain after one day than thermoelastic NiTi wires, and single-strand superelastic NiTi wires probably have a lower alignment rate over four weeks compared with coaxial superelastic NiTi wires. All other evidence on alignment rate, root resorption, time to alignment, and pain is of low or very low certainty in all comparisons. Therefore, there is insufficient evidence to determine whether any particular arch wire material or size is superior to any other. The findings of this review are imprecise and unreliable; well-designed larger studies are needed to give better estimates of the benefits and harms of different arch wires. Orthodontists should exercise caution when interpreting the findings of this review and be prepared to adapt their treatment plans based on individual patient needs.

Introduction: We aimed to examine the effect of amoxicillin and azithromycin suspensions on the microhardness of sliver-reinforced glass ionomer and nano-resin modified glass ionomer (GI). Method: Thirty discs (2 mm height x 4 mm diameter) of each type of GI were prepared, which were randomly assigned to amoxicillin, azithromycin, and artificial saliva groups. Microhardness was evaluated by Vickers hardness test before and after three immersion cycles. Results: The overall model (P < 0.001), before/after intervention (P < 0.001), intervention group (type of antibiotic) (P = 0.013), and type of glass ionomer (P < 0.001) showed significant differences among study groups (P < 0.001). Post hoc test showed only non-significant before/after difference for Azithromycin and artificial saliva (control) groups regarding nano resin-modified GI. Conclusion: We found significant microhardness loss for sliver reinforced GI in comparison to nano resin-modified GI after the immersion cycles. Yet, sliver reinforced GI would have higher level of microhardness than nano resin-modified GI after the immersion cycles. Longer time studies are required to assess trend of microhardness loss.

Immersion of glass ionomer cement (GIC) type II in acid drink like isotonic drink could reduce its compressive strength.This is due to the matrix degradation process of GIC in acid condition. However, there is artificial saliva that canneutralize this condition. The purpose of this study was to evaluate the effect of artificial saliva on compressive strengthof glass ionomer cement type II immersed in isotonic drink. The GICspecimens of 6 x 6 x 12 mm3beam were immersed for24 hours in distilled water, 24 hours in isotonic drink, 24 hours in isotonic drink continued with 72 hours in artificial saliva,48 hours in isotonic drink, and 48 hours in isotonic drink continued with 144 hours in artificial saliva. The compressivestrength was measured using Universal Testing Machine with a crosshead speed of 0.5 mm/min. Statistical analysis wasperformed by one-way ANOVA and post-hoc LSD test (=0.05) showed a significant difference of compressive strength(p<0,05). It was concluded that artificial saliva increases the compressive strength of GIC immersed in isotonic drink.

Introduction: Over the last century, material science has made rapid progress. In orthodontics, not only the materials improved, but also the philosophies have changed. Orthodontic wires, which generate biomechanical forces through brackets for tooth movement, are central to the practice of this profession. Aim: To measure the force deflection properties of Nickel-Titanium (NiTi) wires of four manufacturers, used during orthodontic treatment. Materials and Methods: In this in-vitro study, 480 NiTi wires from four different manufacturers [American Orthodontics (AO), 3M-Unitek (3M), Rabbit Force Orthodontics (RO) and Modern Orthodontics (MO)], of various cross-sections was obtained. Samples of each wire were obtained by cutting the straightest distal portion of an arch wire, thus an approximate length of 5.5 cms was recovered. These wires were subjected to a five point bending test. Five lower anterior stainless steel brackets of tooth number 31, 32, 41, 42 (MBT 0.022” Libral traders Centrino brackets) were fixed with the face of the bracket facing upwards on the acrylic block. Each NiTi wire was placed in the slots of orthodontic brackets and secured with stainless steel ligature wires. These wires were subjected to artificial saliva (Wet Mouth) for 30 days at 37°C. This temperature was regulated by using an incubator. The main assessment criterion was the force deflection property of the wire material. Force deflection was measured using a graph paper where initially the wire was placed and plotted on the graph paper. After the deflection of the wire, it was again placed on the same graph paper such that wire ends coincided and the force deflection at the highest point was measured in millimetres using a digital Vernier Caliper (Mitutoyu). The Design of Experiments (DOE) model was used for analysis and a three-way Analysis of Variance (ANOVA) with wire shape as covariate was used for analysing the variability. Results: A 0.014” NiTi wire showed more mean deflection when compared to 0.016” NiTi wire. When a comparison between 0.016”×0.022” and 0.017”×0.025” NiTi wires was done, mean deflection was almost the same. When round and rectangular wires were compared it showed more mean deflection in round wires. When AO was compared with other three manufacturers. A significant difference (p-value <0.0001) was seen in the mean deflection values of MO and RO. When 3M was compared with the other three manufacturers a significant difference (p-value <0.0001) was seen in the mean deflection values of MO and RO. Three-way ANOVA test with wire shape as co-variate showed a significant amount of difference (p<0.0001) for AO, 3M wires with their counterparts. Conclusion: Round NiTi wires showed more force deflection as compared to rectangular NiTi wires. AO and 3M wires were superior as compared to RO and MO wires. Superelastic wires showed more deflection as compared to conventional and heat- activated NiTi. This can be attributed to the property of the wire. Stiffer the wire, less deflection was seen. Cost of the wire also played a role. Cheaper wires were not able to match the quality and standards of their counterparts.

Introduction: Patients are recommended regular using of mouthwashes to control dental caries or periodontal diseases since orthodontic treatment may have detrimental effects on the tooth structures. However, chemical agents may potentially damage metal components of orthodontic appliances. The aim of this study was to evaluate the influence of three mouthwashes on the surface characteristics of nickel–titanium (NiTi) and Stainless steel (SS) arch wires. Methods and Materials: 15 pieces of 0.016 inch NiTi and 15 pieces of 0.016-inch SS wires were randomly assigned into 5 groups including 2 controls (as- received and artificial saliva) and 3 experimental groups. The samples in all groups were stored in artificial saliva in an incubator at 37˚C for one month, after that, the test groups were immersed in Chlorhexidine 0.12%, Hydrogen peroxide 0.12% and Persica mouth washes for 30 min, 1.5 h and 1.5 h, respectively. Then, the samples were washed by distilled water and returned to artificial saliva for more than two months. Surface topography changes and the number of corrosion holes were characterized via a scanning electron microscope (SEM).Two way ANOVA and Tukey tests were used to compare groups. Results: SEM photographs of the present study showed significant corrosion rate among "as- received" group and Persica (p=0.04), Chlorhexidine (p=0.02), and artificial saliva group (p=0.008) in NiTi wires, but there was no significant difference in the surface topography between any of the groups in SS wires. Conclusion: Alterations in surface of NiTi wires were significantly more than SS wires. Although not significant, 0.12% Chlorhexidine and Peroxide showed higher pitting view on SS and NiTi wires, respectively compared to other mouthwashes

The aim of this study was to evaluate and compare the effect of acidic beverages on the hardness, elastic modulus, and wear resistance of four different resin-based restorative materials. A total of 128 specimens (10 mm diameter, 4 mm thickness) were prepared from a conventional resin composite (Filtek Z250 [Z250]), a giomer bulk-fill (Beautifil Bulk Restorative [BBR]) and two nongiomer bulk-fill materials (Tetric N-Ceram Bulk Fill [TNC] and SonicFill 2 [SF2]). Each material group was divided into four subgroups (n=8) according to the storage media: artificial saliva (control), orange juice, regular Coke, and sports drink. The experimental specimens were immersed in the solutions for 30 minutes, five times a day for 5 days and kept in artificial saliva for an hour between the immersion periods. Control specimens were stored in artificial saliva for 5 days. The nanoindentation test with a Berkovich diamond tip was used to determine the hardness and elastic modulus before and after the 5-day storage periods. Following the nanoindentation tests, the specimens were subjected to a chewing simulator for 120,000 cycles. The specimens were then scanned with a three-dimensional scanner. The wear resistance was analyzed by measuring the volume and height loss. Specimens were observed by environmental scanning electron microscopy. The statistical analyses were performed by analysis of variance, Tukey HDS test, and paired samples t-test (α=0.05). Z250 showed significantly higher elastic modulus in all groups (p<0.05). After erosive cycles, the greatest decrease in hardness and elastic modulus was observed for BBR. TNC showed higher wear resistance than the other resin-based materials (p<0.05). The BBR specimens immersed in acidic solutions showed higher wear rates than the artificial saliva group (p<0.05). Conventional resin composite showed higher hardness and elastic modulus than bulk-fill materials when exposed to acidic beverages but comparable or lower wear resistance. Degradation due to acidic beverages most affected the mechanical properties of giomer bulk-fill.

Introduction Elastomers are considered important allies to orthodontic treatment and due to the aesthetic demand, aesthetic elastomers are increasingly used in adult patients. Objective The aim of this experimental in vitro study was to evaluate the degradation of force of esthetic elastomeric chains, of three different sizes: short, medium and long. Material and method For evaluating the degradation of force, 90 elastomeric chain segments were used, divided into 9 Groups (n=10), as follows: Morelli short elastomer, Morelli medium, Morelli long, Orthometric short, Orthometric medium, Orthometric long, American Orthodontic short, American Orthodontic medium and American Orthodontic long. Acrylic plates with pins were used to provide stretching of the elastomeric chains. The initial stretching force of the elastomeric chain was 150 grams, measured by a tensiometer. After this, they were prestretched to 50% of their original length, measured in an Instron 4411 Universal test machine, and placed on the seating pin on the plate. The plate was immersed in artificial saliva at 37 °C in a plastic receptacle, and removed for measurement after a time interval of 21 days. For statistical analysis, the methodology of mixed models for repeated measures in time and Tukey-Kramer test were used. Degradation of the forces was analyzed by 2-way analysis of variance (ANOVA) and the Tukey test. Result All the elastomeric chains showed statistically significant reduction in force (p&lt;0.05). The American Orthodontic elastomeric chains showed higher reduction in force values, irrespective of the elastic size (p&lt;0.05). Conclusion The three commercial brands studied underwent significant reduction in the quantity of force released; the American Orthodontic brand of elastomer showed the highest value of degradation in force.

Background As the only active component in final treatment phase of Tip-Edge Plus technique, the activation of nickel-titanium orthodontic archwires is one of the factors that affect the torque expression. It is necessary to evaluate the mechanical properties of the nickel-titanium wire used in the final treatment phase in simulated oral environments to forecast the treatment outcomes. Methods The mechanical properties of 171 thermal nickel-titanium wires of 0.35 mm (0.014-in) in diameters with different deflection of 40 mm in length were investigated with three-point bending test. The samples were divided into 2 groups: as-received and bended groups. In the bended group, samples were divided into 7 subgroups according to the amounts of deflection and named by the canine angulations (−25°, −19°, −13°, −7°, −1°, +5°, +11°). The deflection of wires was made by inserting the wires into the deep tunnel of Tip-Edge Plus brackets positioned in plaster casts with different canine angulations to mimic the use of nickel-titanium wires in the final treatment phase. Immersed the bended group in artificial saliva (pH 6.8) and preserved at 37.0°C. Eight durations of incubation were tested: 1 to 8 weeks. Three analogous samples of each group and subgroups were tested per week. Stiffness (YS:E) and the load-deflection characteristics of unloading plateau section were obtained. Results Significant changes in specific mechanical properties were observed in long-term immersed and large deflected wires compared with as-received groups. Both immersion time and deflection affected the mechanical properties of wires in the simulated oral environment, and the two factors had synergistic effect. In groups −25°, −19° and −13°, stiffness (YS:E) increased then decreased and average plateau force and ratio of variance decreased then increased correspondingly at specific time. Conclusions In the final treatment phase of Tip-Edge Plus technique, the mechanical properties of nickel-titanium wire are associated with the using time and amounts of deflection and it may affect treatment outcomes. As the main reason for wire deflection, canine crown angulation plays an important role in the wire performance. It may be wise to focus on the canine crown angulations and using time in clinic with Tip-Edge Plus technique and make proper adjustment to help to make sure the treatment outcomes.