Retainer Wire Research Articles

Comparison of Shear Bond Strength of Different Wire-Composite Combinations for Lingual Retention: An in Vitro Study

Context: As lingual bonded retainers are required for long-term retention in the oral cavity, the wire-composite combination of choice may be the determining factor for the success of lingual bonded retainers. Aim: We compared the shear bond strength of different wire-composite combinations used for lingual bonded retainers and identified the combination of choice for lingual retention in terms of the shear bond strength. Materials and Methods: A total of 108 extracted human maxillary premolars in pairs were divided into 6 groups of 9 samples each. Three different types of retainer wires (namely, Respond [Ormco Corp., Orange, CA, USA], Leone Ligature Wire [Leone S.p.a., Firenze, Italy], and SRW™ Stranded Retention Wire [Ortho Classic Inc., USA]) were bonded to the teeth with the composites (G-aenial™ Universal Flo and Tetric N-Flow). The shear bond strength was measured on debonding using universal testing machine INSTRON. Results: The maximum shear bond strength (58.28 N) was observed in group IV (Respond wire with Tetric N-Flow), whereas the minimum (25.28 N) was observed in group VI (SRW™ Stranded Retention Wire with Tetric N-Flow). A highly significant difference was observed when the shear bond strength of group IV was compared with all the other groups. Conclusions: The maximum shear bond strength was observed in the wire-composite combination of Respond dead-soft wire with Tetric N-Flow composite. Therefore, it could be the wire-composite combination of choice for bonded lingual retainer.

Survival rate of two orthodontic bonded retainer wires

We read the article “Clinical effectiveness of two orthodontic retainer wires on mandibular arch retention” (Gunay F, Oz A. Am J Orthod Dentofacial Orthop 2018; 153:232-8) with great interest. We congratulate the authors for conducting a robust study with an effective study design on this important topic. However, we would seek certain clarifications from the authors on several points:1.In paragraph 1 of the statistical analysis section, the authors mention that lingual retainer survival rates over 12 months were evaluated by means of the Kaplan-Meier test and that differences in retainer survival curves by retainer wire type were evaluated by means of the log-rank test. In Fig 3, the authors draw a Kaplan-Meier curve depicting the cumulative survival rates of group 1 (0.0175-inch 6-stranded stainless steel retainer wire) and group 2 0.0195-inch dead-soft coaxial retainer wire), but the graph touches zero percent in both groups over a 12-month follow-up period. This means that survival or success of the bonded retainer is 0% at the end of 12 months in both groups, although it is 86.8% in group 1 and 81.1% in group 2 according to Table II (log-rank test: χ2 = 0.661; P = 0.416). Figure 3 and Table II completely contradict each other. We think that the graph should be drawn as shown in Figure (Corrected).1Egli F. Bovali E. Kiliaridis S. Cornelis M.A. Indirect vs direct bonding of mandibular fixed retainers in orthodontic patients: comparison of retainer failures and posttreatment stability. A 2-year follow-up of a single-center randomized controlled trial.Am J Orthod Dentofacial Orthop. 2017; 151: 15-27Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar, 2Dawson B. Trapp R.G. Research question about means in three or more groups.in: Dawson B. Trapp R.G. Basic and clinical biostatistics. 4th ed. McGraw Hill, New York2004: 163-189Google Scholar2.The authors applied repeated-measures analysis of variance (ANOVA) for irregularity measurements and intercanine distance. Intragroup comparison at different time points is mentioned, but what is the intergroup difference at different time points of the above parameters? In Tables IV and V, 2 different F-values are mentioned, and it seems that the authors have applied 1-way repeated-measures ANOVA separately for each treatment group and not repeated-measures ANOVA for both groups together. Our question is why intergroup repeated-measures ANOVA2Dawson B. Trapp R.G. Research question about means in three or more groups.in: Dawson B. Trapp R.G. Basic and clinical biostatistics. 4th ed. McGraw Hill, New York2004: 163-189Google Scholar was not applied.3.Intergroup comparison (Table VI) of mean irregularity measurement (mm) difference between post-treatment and 12-month retention period (T5-T1) via Mann-Whitney test gives us vital information that mandibular arch irregularity is significantly higher in group 2 than in group I. Similarly, it would also be pertinent to know the results of a Mann-Whitney test for the difference in mean intercanine distance between the 2 groups. This result may help us in localizing the irregularity site so that adequate stress can be given to the areas requiring maximum retention. The authors should comment on why this relevant information was not shared. We emphasize that by no means are we disregarding the efforts of the authors in conducting this trial, but our intention is that correct and relevant information should reach the readers of this journal. Clinical effectiveness of 2 orthodontic retainer wires on mandibular arch retentionAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 153Issue 2PreviewThe aim of this study was to evaluate and compare the clinical success of 2 lingual retainer wires. Full-Text PDF Author's responseAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 155Issue 1PreviewThank you so much for your interest and the valuable contributions you have made to our work. Full-Text PDF

Nickel Ions Release from Orthodontic Retention Wires after Dental Bleaching

In order to preclude relapse after the orthodontic treatment have been completed, majority of orthodontists depend on the permanent retention with bonded lingual retainer wires. It is essential to study the home dental bleaching effect on ions release from permanent retention wires with the increasing demand for bleaching to have gorgeous smile. Our vitro study intended to demonstrate the home dental bleaching gel (carbamide peroxide) effect on Nickel release from orthodontic fixed retainer wires, and how does the type of retainer wire, the carbamide peroxide concentration and the exposure duration effect of carbamide peroxide on the release of nickel ions. The sample was composed of 60 lingual retainer wires of two types (3 braided strands/orthotechnology, and 6 coaxial strands/orthotechnology) and two types of at-home bleaching gel (35% carbamide peroxide/opalescence PF/Ultradent, and 16% carbamide peroxide/polanight SDI). By using a brush, a thin coating of bleaching gel about 1-mm thickness was added onto one surface of the wire and kept for (30 minutes for 35% carbamide peroxide bleached wires and 90 minutes for 16% carbamide peroxide bleached wires-following the instructions of the manufacturer), for each kind of bleaching, after that the wires were bathed and kept at room temperature in 10 ml of artificial saliva in a wrapped container, for 7 days this process was repeated day-to-day. Via flameless atomic absorption spectrophotometer in ppm, nickel ions release was measured. Non significant differences were result between two types of wires and between 30% carbamide peroxide and control group, 16% carbamide peroxide showed significantly less Nickel release compared with control group and 35% carbamide peroxide group. Nickel release was not affected by the wire kind, but if may be affected by the carbamide peroxide concentration and the exposure time. The 16% carbamide peroxide documented the smallest values, that means the nickel release from retention wires was decreased as the exposure time increased to low carbamide peroxideconcentration.

Periodontal parameters of two types of 3 x 3 orthodontic retainer: a longitudinal study.

ABSTRACTIntroduction: bonded fixed retainers are often used to stabilize the results obtained with the orthodontic treatment. It is important that they do not prejudice dental health, as they will be used for a long period. Objective: The purpose of the present study was to compare periodontal indexes between two types of bonded fixed retainers, conventional 3 x 3 plain retainer (0.8-mm orthodontic wire, bonded to the canines only) and a manufactured braided retainer (0.2 x 0.7-mm stainless steel wire, bonded to all anterior teeth) after use. Methods: a test group of 15 volunteers (aged from 18 to 25 years) used both the conventional retainer and braided retainer for six months. A randomized longitudinal study design, with a two week washout interval, was applied. The dental plaque index, gingival index and dental calculus index were evaluated. Furthermore, the calculus accumulated along the retainer wire was measured and all patients answered a questionnaire about the use, acceptance and comfort of both types of retainers. Results: the scores for plaque and gingival indexes were higher for the braided retainer (p< 0.05) on the lingual and proximal surfaces. The same occurred with the calculus index on the lingual surfaces (p< 0.05). The calculus index along wire was higher for the braided retainer (p< 0.05). All patients preferred the conventional retainer, and said that it was also more comfortable to use. Conclusion: it was concluded that the conventional retainer showed better periodontal indexes than the braided type.

Displacement of teeth without and with bonded fixed orthodontic retainers: 3D analysis using triangular target frames and optoelectronic motion tracking device.

The objective of this study was to evaluate the anterior tooth movement without and with bonded fixed orthodontic retainers under incremental loading conditions. Six extracted mandibular anterior human teeth were embedded in acrylic resin in True Form I Arch type and 3D reconstruction of Digital Volume Tomography (DVT) images (0.4 mm3 voxels) were obtained. The anatomy of each tooth was segmented and digitally reconstructed using 3D visualization software for medical images (AMIRA, FEI SVG). The digital models of the teeth were repositioned to form an arch with constant curvature using a CAD software (Rhinoceros) and a base holder was designed fitting the shape of the roots. The clearance between the roots and their slot in the holder was kept constant at 0.3 mm to replicate the periodontal ligament thickness. The holder and the teeth were then manufactured by 3D printing (Objet Eden 260VS, Stratasys) using a resin material for dental applications (E = 2-3 GPa). The 3D-printed teeth models were then positioned in the holder and the root compartments were filled with silicone. The procedure was repeated to obtain three identical arch models. Each model was tested for tooth mobility by applying force increasing from 5 to 30 N with 5 N increments applied perpendicular on the lingual tooth surface on the incisal one third (crosshead speed: 0.1 mm/s). The teeth on each model were first tested without retainer (control) and subsequently with the bonded retainers (braided bonded retainer wire; Multi-strand 1 × 3 high performance wire, 0.022″ × 0.016″). Tooth displacement was measured in terms of complicance (F/Δ movement) (N/mm) using custom-built optoelectronic motion tracking device (OPTIS) (accuracy: 5 µm; sampling rate: 200 Hz). The position of the object was detected through three LEDs positioned in a fixed triangular shape on a metal support (Triangular Target Frame). The measurements were repeated for three times for each tooth. Data were analyzed using mixed model with nesting (alpha = 0.05). The use of retainer showed a significant effect on tooth mobility (0.008 ± 0.004) compared to non-bonded teeth (control) (0.014 ± 0.009) (p < 0.0001). The amount of displacement on the tooth basis was also significantly different (p = 0.0381) being the most for tooth no. 42 (without: 0.024 ± 0.01; with: 0.012 ± 0.002) (p = 0.0018). No significant difference was observed between repeated measurements (p = 0.097) and the incremental magnitude of loading (5-30 N: 0.07 ± 0.01-0.09 ± 0.02) (p > 0.05). Mandibular anterior teeth showed less tooth mobility when bonded with stainless steel wire as opposed to non-bonded teeth but the tooth mobility varied depending on the tooth type. Intermittent increase in loading from 5 to 30 N did not increase tooth displacement.

The effect of prior sandblasting of the wire on the shear bond strength of two different types of lingual retainers

The aim of this study was to evaluate the effect of total surface sandblasting on the shear bond strength of two different retainer wires. The null hypothesis was that there is no difference in the bond strength of the two types of lingual retainer wires when they are sandblasted. One hundred and sixty human premolar teeth were equally divided into four groups (n=40). A pair of teeth was embedded in self-curing acrylic resin and polished. Retainer wires were applied on the etched and rinsed surfaces of the teeth. Four retainers were used: group 1: braided retainer (0.010×0.028″, Ortho Technology); group 2: sandblasted braided retainer (0.010×0.028″, Ortho Technology); group 3: coaxial retainer (0.0215″ Coaxial, 3M) and group 4: sandblasted coaxial retainer (0.0215″ Coaxial, 3M). The specimens were tested using a universal test machine in shear mode with a crosshead speed of one mm/min. One-way analysis of variance (Anova) was used to determine the significant differences among the groups. There was no significant difference (P=0.117) among the groups according to this test. The null hypothesis was accepted. There was no statistically significant difference among the shear bond strength values of the four groups.

Evaluation of Bond Strength and Load Deflection Rate of Multi-stranded Fixed Retainer Wires: An In-Vitro Study.

Background:Fixed orthodontic retainers must be well retained on the tooth surfaces, allow physiologic movement of teeth and exert minimal forces on the teeth to be retained. Previous studies analyzed the bond strength and amount of deflection caused due to the debonding force but not the magnitude of force needed for unit deformation.Aims:This study aims to evaluate and compare the bond strength and load deflection rate (LDR) of three different fixed retainer wires.Materials and Methods:The wires were divided into three Groups: A – three-stranded twisted ligature wire, B – Bond-A-Braid (Reliance Orthodontics), and C – three-stranded twisted lingual retainer wire (3M Unitek). Twenty models were prepared for each group with a passive 15 mm long lingual retainer wire bonded to two lower incisors. An occlusogingival force was applied to the wire until it debonded. For LDR, three-point bending test was done at 0.5 mm deflection. These forces were measured using a Universal Instron Testing Machine.Statistical Analysis:Mean bond strength/LDR and pairwise comparisons were analyzed with one-way ANOVA and Tukey's honest significant difference post hoc test, respectively.Results:Group C exhibited the highest mean bond strength and LDR of 101.17N and 1.84N, respectively. The intergroup comparisons were all statistically significant.Conclusion:Compared to the other two wire types, Group C might be better retained on the teeth due to its higher bond strength. With its relatively higher LDR value, it may resist deformation from occlusal forces, thereby reducing inadvertent tooth movement and yet remain flexible enough to allow physiologic tooth movements.

Effects of Clitoria ternatea linn. flower juice on the elasticity, texture and pores of the denture retainer component

Clitoria ternatea flower has a variety of antioxidant compounds. To analyze the effects of the flower juice on the elasticity, roughness and pore components of partial denture retainer (stainless steel wire). 0.8 cm of retainer wire components were soaked in the juice (1 g/mL) for 4, 6, and 8 hours at room temperature. Polident and mineral water were used as controls. Measurement of the elasticity, texture and pore of each component based on the addition of wire length, number of pixels, and pores average. C. ternatea flower juice showed no statistically significant difference effects among all type solutions on the elasticity, texture and pore of the retainer component. C. ternatea flower juice did not cause alteration in the retainer component in terms of elasticity, texture and pore.

A robust method of bonding fixed lingual retainer

Flexible spiral wire (FSW) is commonly used as a bonded retainer. Accurate and passive placement of a FSW requires a lot of skill and dexterity. Stabilizing the retainer wire with a plier or finger pressure is very demanding and various auxiliaries like elastics, dental floss and silicone transfer tray aid in securing the retainer in place, however their precision is questionable. We used a simple bonding technique, using a laboratory-prepared Memosil 2, is an accurate, effective, and predictable method for bonding fixed multistranded wire retainer.

Assessing the feasibility of yttria-stabilized zirconia in novel designs as mandibular anterior fixed lingual retention after orthodontic treatment.

The purpose of this study is to explore the feasibility of yttria-stabilized zirconia (Y-TZP) in fixed lingual retention as an alternative to stainless steel. Exploratory Y-TZP specimens were milled to establish design parameters. Next, the specimens were milled according to ASTM standard C1161-13 and subjected to 4-point flexural tests to determine material properties. Finite elementanalysis was used to evaluate 9 novel cross-sectional designs, which were compared with stainless steel wire. Each design was analyzed under loading conditions to determine von Mises and bond stresses. The most promising design was fabricated to assess the accuracy and precision of current CAD/CAM milling technology. The superior design had a 1.0×0.5mm semielliptical cross-section and was shown to be fabricated reliably. Overall, the milling indicated a maximum percent standard deviation of 9.3 and maximum percent error of 13.5 with a cost of $30 per specimen. Y-TZP can be reliably milled to dimensions comparable with currently available metallic retainer wires. Further research is necessary to determine the success of the bonding protocol and the clinical longevity of Y-TZP fixed retainers. Advanced technology is necessary to connect the intraoral scan to an esthetic and patient-specific Y-TZP fixed retainer.

A Protocol for Treatment of Minor Orthodontic Relapse During Retention.

Successful orthodontic treatment presupposes that the esthetic and functional outcomes are maintained. Bonded retainers on the incisors and canines provide this stability. Failure of one or two units exposes the teeth to a relapse. This article describes the use of a retainer wire and an elastic device to provide rapid, effective and esthetic correction of incipient crowding. After removing the retainer, a fixed appliance comprising a replacement retainer and a clear elastic are positioned. This device exerts a free tipping force on malpositioned teeth. The space required to realign the contact points is obtained by stripping. When the misaligned teeth are corrected, they are bonded to the retainer and the height of the incisal edges is equalized. The combination of a new elastic-activated retainer and stripping makes it possible to ensure rapid and effective correction of moderate relapsed crowding. This article demonstrates the efficacy of a retainer used to correct incipient relapsing crowding. The esthetics of the anterior alignment is restored by means of an almost invisible device. This solution also permits functional guidance to be restored with minimal intervention on the dental tissues while avoiding conventional esthetic techniques involving lingual brackets. (J Esthet Restor Dent 28:359-366,2016).

Torque resistance of different stainless steel wires commonly used for fixed retainers in orthodontics.

Movements of teeth splinted by fixed retention wires after orthodontic treatment have been observed. The aetiological factors for these movements are unknown. The aim of this in vitro study was to compare the resistance to torque of different stainless steel wires commonly used for fixed retainers in orthodontics. Torquing moments acting on a retainer wire were measured in a mechanical force testing system by applying buccal crown torque to an upper lateral incisor in both a 3-teeth and in a 2-teeth setup. Seven stainless steel wires with different shape, type (plain, braided, coaxial, or chain) and dimensions were selected for this study. For a torquing angle of 16.2° in the 3-teeth setup torsion moments can vary between 390 cNmm and 3299 cNmm depending on the retainer wire. For the 2-teeth setup the torsion moments are much smaller. Exposure to the flame of a butane-gas torch for 10 seconds to anneal the wire reduces the stiffness of the retainer wire. Clinicians must select wires for fixed retainers very carefully since the difference in resistance to torque is large. A high level of torque control can be achieved with a plain 0.016 × 0.016-inch or a braided 0.016 × 0.022-inch stainless steel wire. A tooth attached by a retainer wire to only one neighbouring tooth is less resistant to torque than a tooth connected to two neighbouring teeth. Annealing a retainer wire with a flame reduces the stiffness of the wire markedly and can lead to a non-uniform and non-reproducible effect.

Comparison of the effects of different retention appliances on the oxidant–antioxidant system

The aim was to compare oxidative stress (OS) levels with different types of retention appliance. Thirty orthodontic patients were divided into three groups: Group 1 (Essix retainer), Group 2 (lingual retainer with stainless steel retainer wire), and Group 3 (lingual retainer with fiber-reinforced material). OS was assessed in the subjects’ saliva. Saliva samples were taken from the patients at T0 (before using the retention appliance), T1 (first month of retention), and T2 (third month of retention). The specimens were investigated to detect changes in total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI). TAS values in Group 2 were significantly higher than in Group 3. TOS values in Group 3 were significantly lower than in the other groups. TOS values in Group 2 were lower than in Group 1. OSI values of Group 1 were higher than those in Group 2 or 3. There was no statistically significant difference among the time periods. The type of retention appliance affected OS values. A fiber-reinforced material may have a lower OSI. OS or products can affect some systemic disease; therefore, the selection of the retainer will be important on these patients.

A simple technique for stabilizing fixed retainer wires after de-bonding

A simple technique for stabilizing fixed retainer wires after de-bonding

Bond strength of aged lingual retainers

Introduction: The purpose of this study was to examine the tensile bond strength (TBS) of two different lingual retainer (LR) composite systems and three LR wires after they were aged by loadcycling and thermocycling. Materials and Methods: A 15 mm length of wire was bonded to the lingual surfaces of pairs of human incisors using two bonding techniques. Seventy-two pairs of incisors were placed into six groups, and loadcycling (50,000 times) and thermocycling (10,000 times) were performed. The failure characteristics examined included the maximum force for debonding and the site of failure. The adhesive remnant index scores were calculated. Data were compared by two-way analysis of variance and Tukey highly significant difference analysis. Results: All groups generally showed statistically significant differences in TBS score (P < 0.05). For each group, the highest average TBS score (P < 0.05) was obtained from a Transbond LR + Remalloy LR combination. The main failure type was a mixed failure. Conclusions: Retainer wire and composite combinations had significant differences. One of the best selection criteria for LRs is the determination of the bond strength needs of a case.

A simple technique for stabilizing fixed retainer wires after de-bonding

Many orthodontists believe that the only way to maintain the ideal alignment after orthodontic treatment would be by permanent retention in the form of a fixed lingual wire. Broken or de-bonded retainers are difficult to be replaced as securing them in place becomes more difficult after removal of the fixed orthodontic appliance. Introduced here a simple technique developed for stabilizing the fixed retainer wire after de-bonding.

Shear bond strength of different fixed orthodontic retainers

Abstract Objective To compare the shear bond strength of different fixed retainer wire diameters bonded using a conventional composite resin or a specific retainer composite. Materials and methods One-hundred-and-twenty extracted human premolar teeth were divided into six groups. After conventional acid etching with a 37% phosphoric acid gel for 30 seconds, twist flex wires of various diameters (0.0175″, 0.0215″, 0.032″) were bonded as fixed retainers. Conventional bracket adhesive (Filtek Z250) or retainer specific adhesives (Transbond LR) were used. After curing, the specimens were stored for 24 hours in distilled water at 37°C and, thereafter, subjected to 500 thermal cycles. The specimens were then debonded using a Universal Instron machine. The site of failure was recorded for each specimen and the shear bond strength calculated. Statistical analyses were provided using a Chi-square test for failure site and a two-way ANOVA test to assess shear bond strength. Results The site of failure was predominantly at the wire composite interface in all groups. The specific retainer composite showed a significantly higher shear bond strength compared with conventional composite (p &lt; 0.001). There was a statistically significant difference between the three wire diameters (p &lt; 0.001); the 0.0215” wire had the highest shear bond strength, whereas the 0.032” wire had the least shear bond strength. Conclusions The site of failure was unrelated to wire diameter or adhesive. The optimal combination to maximise the bond strength of fixed retainers appeared to be a specific retainer adhesive and a wire diameter of 0.0215″.

Shear bond strength of different retainer wires and bonding adhesives in consideration of the pretreatment process.

IntroductionWe aimed to compare the shear bond strength (SBS) of three different retainer wires and three different bonding adhesives in consideration of the pretreatment process of enamel surface sandblasting.Methods400 extracted bovine incisors were divided into 10 groups of 20 paired specimens each. 10 specimens of each group were pretreated by enamel sandblasting. The retainer wires Bond-A-Braid™, GAC-Wildcat®-Twistflex and everStick®ORTHO were bonded to the teeth with the adhesives Transbond™-LR, Tetric-EvoFlow™ and Stick®FLOW and then debonded measuring the SBS.ResultsWhile sandblasting generally increased SBS for all tested combinations, the retainer wires bonded with Transbond™-LR showed the highest SBS both with and without prior sandblasting. Significantly lower SBS were found for Tetric-EvoFlow™ that were comparable to those for everStick®ORTHO.ConclusionsPretreatment of enamel surfaces by sandblasting increased the SBS of all retainer-wires. Transbond™-LR showed the best results compared to Tetric-EvoFlow™ and everStick®ORTHO, while all combinations used provided sufficient bonding strengths for clinical use.

Comparative evaluation of microleakage of lingual retainer wires bonded with three different lingual retainer composites: an in vitro study.

To evaluate microleakage when two types of retainer wires were bonded with two light cured and a self cured lingual retainer composites. Total 120 freshly extracted human mandibular incisor teeth were collected and separated into six subgroups of 20 teeth each. Two different wires, a 0.036 inch hard round stainless steel (HRSS) wire sandblasted at the ends and 0.0175 inch multistranded wire bonded onto the lingual surfaces of the incisors with three different types of composite resins of 3M company; Concise Orthodontic (self-cure), Transbond XT (light-cure) and Transbond LR (light-cure). Specimens were further sealed with a nail varnish, stained with 0.5% basic fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage for the enamel-composite and wire-composite interfaces. Statistical analysis was performed by Kruskal-Wallis and Mann-Whitney U-tests. For HRSS wire, at the enamel-composite interface, the microleakage was least with Transbond LR followed by Concise Orthodontic and greatest for Transbond XT (p<0.05). At the wire composite interface too, the microleakage was in order of Transbond LR<Concise Orthodontic<Transbond XT. For the multistranded wire, at the enamel-composite interface, the microleakage was least with Transbond LR followed by Concise Orthodontic and Transbond XT (p<0.05). At the wire composite interface too, it was seen that microleakage was the least with Transbond LR followed by Concise Orthodontic and Transbond XT. Transbond LR in combination with 0.0175 inch multistranded wire showed least microleakage amongst the groups studied.

Tensile force measurement by using different lingual retainer wires, bonding materials types and thickness (A comparative in vitro study)

The bonded orthodontic retainer constructed from multistrand wire and composite is an efficient esthetic retainer, which can be maintained long-term. Clinical failures of bonded orthodontic retainers, most commonly at the wire/composite interface, have been reported. This in vitro investigation aimed to evaluate the tensile forces of selected multistrand wires and composite materials that are available for use in the construction of bonded fixed retainers. Materials and Methods: The study sample includes 120 wires with three types of retainer wires (3 braided Orthotechnology, 8 braided GH then the composite was light cured for 40 seconds and the specimens were stored in artificial saliva at 37°C in the incubator for 24 hours. The ends of the wire were drawn up and tensile force was applied through Tinius-Olsen universal testing machine until the resin failed and the results were recorded in Newton (N). Results: Statistical analysis showed that there was a highly significant difference (P ≤ 0.01) among the mean values of tensile forces of the three types of retainer wires in each thickness of composite with exception of a non significant difference (P > 0.05) between (3 braided) and (8 braided) and a non significant difference (P > 0.05) between (3 braided) and (6 coaxial) in both thickness of composite, a highly significant difference (P ≤ 0.01) between the two thickness of both composite types in each wire type and a highly significant difference (P ≤ 0.01) between the two types of composite in each wire type of both thickness of composite. Conclusion: The result of this study revealed that the 8 braided strands retainer wire shows the highest values of tensile force among the tested retainer wires, the non flowable composite demonstrates a higher tensile force than the flowable composite and increasing the thickness of composite overlying the wire increased the force required to detach the wire from the composite.