Active Self-ligating Brackets Research Articles

Passive Self-Ligating Bracket Systems: A Scoping Review of Their Claims Regarding Efficiency and Effectiveness in Orthodontic Treatment

Passive self-ligating bracket systems (PSLBs), such as the Damon® system (Ormco, US) and SmartClip (3M Unitek®, US) claim advantages over other types of brackets regarding efficiency and effectiveness. However, some studies have questioned their qualities, particularly during the alignment stage, in arch development, and regarding stability of results. This article aims to conduct a scoping review from the past decade’s literature (2013–2023) regarding these assertions about PSLBs. A comprehensive search was performed on several databases. With at least one comparison between PSLBs and the other two bracket types, the inclusion criteria were restricted to English-written randomized controlled trials and split-mouth design studies involving patients receiving orthodontic treatment using PSLB, active self-ligating bracket systems (ASLBs), or conventional/traditional bracket systems (CBs). After screening and manual analysis of the selected studies, only 39 were chosen for the review. Most of the efficiency and effectiveness results from research conducted in the past ten years did not indicate any appreciable differences between the three different types of brackets; therefore, the evidence on whether PSLB is better than CBs and ASLBs is equivocal. Further research is necessary to understand the distinctions between passive self-ligating and other bracket systems and establish the optimal utilization of each system in clinical settings.

Operating time for wire ligation with self-ligating and conventional brackets:A standardized in vitro study.

Operating time is one of the main advantages attributed from the literature to the use of self-ligating brackets (SLB). The aim of this study is to investigate the time needed for a complete archwire change procedure with conventional brackets (CB) and SLBs in a standardized in vitro research setting, comparing operators with different expertise. Thirty-three participants were divided into three equal groups: undergraduate students, postgraduate students, and orthodontists. Three sets of typodonts bonded with three types of brackets, including passive SLBs, active SLBs, and CBs using both steel and elastic ligatures were investigated. Operators had to insert, ligate, deligate, and remove wires in sets of typodonts representing an actual dentition before and after orthodontic treatment, mounted in phantoms. Archwire change procedure times were compared between the different bracket/ligation systems, between the before- and after-treatment typodonts, and between operators. There were significant differences between SLBs and CBs, the greatest difference being 11 min 16 s between passive SLBs and CBs ligated with metallic ligatures at T0, for the total archwire change procedure by the operators overall. For all the operators, there was a statistically significant difference in total archwire change procedure time between the systems. The undergraduate students were the slowest when using CBs, but they showed no significant difference compared to the other users when using SLBs. SLBs can offer a significant operating time reduction compared to CBs, and time saving is not dependent on the operator's experience and training.

Comparative study on conventional ligation and self ligation bracket systems

Aim: The purpose of the present study was to evaluate the comparison between conventional ligation and self-ligation bracket system. Methodology: Seven hundred and sixty two patients, consecutively treated with fixed appliances, were evaluated retrospectively. All patients were treated by one orthodontist in a private orthodontic practice. Three hundred and eighty three patients were treated using a conventional pre-adjusted bracket system and 379 patients were treated with active self-ligating brackets. The total treatment time, number of appointments, appointment intervals, number of bracket breakages and number of unscheduled emergency appointments were recorded. Pretreatment characteristics identified by the ICON were related to these variables. Results: The average treatment duration was 15.7 months (Range: 4.1–40.5 months; SD: 5.6 months). Comparable amounts of time were spent in rectangular and round archwires by both appliances. Overall, there was no statistically significant difference between the durations of treatment with active self-ligating brackets and conventional pre-adjusted brackets. The number of debonded brackets and other emergency visits was significantly higher in patients treated with active self-ligating brackets. The treatment characteristics associated with prolonged treatment were: extraction of teeth, a Class II molar relationship and the degree of maxillary crowding or spacing.

Comparative study on conventional ligation and self ligation bracket systems

Aim: The purpose of the present study was to evaluate the comparison between conventional ligation and self-ligation bracket system. Methodology: Seven hundred and sixty two patients, consecutively treated with fixed appliances, were evaluated retrospectively. All patients were treated by one orthodontist in a private orthodontic practice. Three hundred and eighty three patients were treated using a conventional pre-adjusted bracket system and 379 patients were treated with active self-ligating brackets. The total treatment time, number of appointments, appointment intervals, number of bracket breakages and number of unscheduled emergency appointments were recorded. Pretreatment characteristics identified by the ICON were related to these variables. Results: The average treatment duration was 15.7 months (Range: 4.1–40.5 months; SD: 5.6 months). Comparable amounts of time were spent in rectangular and round archwires by both appliances. Overall, there was no statistically significant difference between the durations of treatment with active self-ligating brackets and conventional pre-adjusted brackets. The number of debonded brackets and other emergency visits was significantly higher in patients treated with active self-ligating brackets. The treatment characteristics associated with prolonged treatment were: extraction of teeth, a Class II molar relationship and the degree of maxillary crowding or spacing.

Comparative Evaluation of Two Bracket Systems' Kinetic Friction: Conventional and Self-Ligating.

Friction is an intensely studied feature in orthodontics, as the sliding mechanics approach remains one of the most utilized techniques in current practice, and the question of whether self-ligating brackets produce less friction than conventional brackets still stands. The objective of this study was to compare a self-ligating system with different closing mechanisms and a conventional system with different ligating mechanisms regarding their frictional properties. Laboratory measurements were performed using an advanced materials testing machine generating tensile strength and load at maximum Load values, which were statistically analyzed and compared. These two parameters have been associated with the frictional resistance generated at the archwire–bracket slot interface. Statistically significant results were obtained when comparing the active self-ligating brackets with the passive self-ligating (tensile strength mean 1.953, SD 0.4231; load at maximum moad mean 6.000, SD 1.3000) and conventional brackets (tensile strength mean 1.953, SD 0.4231; load at maximum load mean 6.000, SD 1.3000), as well as when comparing the passive self-ligating brackets with the conventional brackets (tensile strength mean 1.708, SD 0.8628; load at maximum load mean 5.254, SD 2.645). The active self-ligating brackets tended to produce more friction when compared to the passive self-ligating brackets but were similar to conventional brackets with stainless steel ligatures.

Friction and archwire engagement in contemporary self-ligating appliance systems : An in vitro comparison.

The aim of this study was to compare classical friction (FR) in passive self-ligating brackets (P-SLBs), active self-ligating brackets (A-SLBs) and atraditional twin bracket, in vitro, and to identify the point of initiation of bracket-archwire engagement. Nine bracket systems of 0.022 in slot size were FR tested: 5 P‑SLB systems; 4 A‑SLB systems; and a control group of twin brackets with elastomeric ligatures. Single upper right central incisor brackets were mounted on acustom metal fixture for testing. Straight sections of various round and rectangular nickel-titanium (NiTi) archwires (0.016, 0.018, 0.018 × 0.018, 0.020 × 0.020, 0.016 × 0.022, 0.017 × 0.025, 0.019 × 0.025, and 0.021 × 0.025 in) were ligated to the bracket and peak static FR (cN) was measured with an Instron Universal Testing Machine. Ten unique tests each utilizing anew bracket and new archwire were conducted for each group in the dry state. FR was significantly different between control, P‑SLB and A‑SLB systems (P < 0.001). P‑SLB groups displayed no significant differences in FR between each other, regardless of archwire size. A‑SLB groups did exhibit significant differences in FR between each other depending on both the bracket system and archwire size. Each A‑SLB system tested possessed adistinctly different pattern of initiation of bracket-archwire engagement. FR between the archwire and bracket slot differs between P‑SLB and A‑SLB systems, with adistinct pattern of FR and bracket-archwire engagement for each A‑SLB system. Understanding the different bracket-wire interactions of SLB systems should help orthodontic clinicians to plan effective and efficient biomechanics with the bracket system of their choice.

Is there any difference between conventional, passive and active self-ligating brackets? A systematic review and network meta-analysis

To test the null hypothesis that there was no difference in treatment efficiency between therapies undertaken with conventional (CBs), passive self-ligating (PSLBs) or active self-ligating (ASLBs) brackets. An electronic search was performed in 3 data bases (Pubmed, Web of Science, Cochrane Library) from their origin up to January 2019. Additional references were hand searched. Search was strictly restricted to randomized controlled trials (RCTs) and split-mouth design studies (SMDs). RCTs and SMDs were initially processed separately and subsequently combined in a network meta-analysis. The following variables were evaluated: treatment duration, number of visits, occlusal outcomes, alignment rate, transverse arch dimensional changes, incisor position modification, rate of space closure, anchorage loss, bond failure, root resorption, perception of discomfort during the initial phase of alignment, time to ligate in or to untie an archwire, periodontal variables, quality of life. On 229 papers, 30 RCTs and 9 SMDs were finally included in this study. Out of 85 comparisons, 16 only revealed statistically significant differences. It was quicker to untie and ligate an 0.014 NiTi arch from/in 6 ASLBs anterior ceramic brackets compared to 6 ceramic CBs. It was also more painful to insert and remove an 0.019×0.025 SS wire in/from PSLB's brackets compared to CB's attachments. Compared to conventional brackets, there was less maxillary incisor proclination with PSLBs in non-extraction cases. Moreover, there was less bleeding on probing 4-5 weeks after bonding with PSLBs compared to CBs brackets. The only significant difference between ASLBs and PSLBs was that alignment was 10 days faster with active self-ligating braces compared with passive self-ligating braces even if treatment duration between ASLBs and PSLBs was not significantly different. The network meta-analysis revealed that IMPA was greater in extractions cases with CBs compared with both ASLBs (+2,5°) and PSLBs (+1,6°). The vast majority of the studied variables did not show any significant differences between the three types of brackets. The most significant findings were that it was quicker to insert and remove archwires from ASLBs compared to CBs, and it was more painful to insert and remove an 0.019×0.025" stainless steel wire in/from PSLBs compared to CBs. The major difference between ASLBs and PSLBs was that alignment was 10 days faster with active self-ligating braces compared with passive self-ligating braces even if treatment duration between ASLBs and PSLBs was not significantly different. Most of the claims put forward by the suppliers were not substantiated by our network meta-analysis.

Comparison of multiforce nickel-titanium wires to multistrand wires without force zones in bending and torque measurements.

The aim was to compare rectangular multiforce nickel-titanium (NiTi) wires to rectangular wires with only one force zone. Both types of wires are primarily intended for use during the levelling phase of orthodontic treatment. Thus, basic mechanical properties were examined by means of athree-point bending test. Torque expression, which is dependent on both wire parameters and interslot distances, was analyzed using the Orthodontic Measurement and Simulation System (OMSS). Four multizone products were tested: DuoForce™ (Forestadent, Pforzheim, Germany), TriTanium™ (American Orthodontics, Sheboygan, WI, USA), Triple Force™ (ODS, Kisdorf, Germany), Bio-Active™ (GC, Breckerfeld, Germany), and two multistrand products without force zones: anine-strand NiTi, TurboWire™ (Ormco, Orange, CA, USA) and an eight-strand stainless steel (SS) wire, Multibraid™ (GAC, Dentsply Sirona, York, PA, USA). All the wires had the dimension 0.40 mm × 0.56 mm (0.016 inch × 0.022 inch) except the nine-strand NiTi wire TurboWire™, which had a dimension of 0.43 mm × 0.65 mm (0.017 inch × 0.025 inch). Six different bracket systems in the 0.018 inch slot system were chosen: the conventional brackets discovery® and discovery® smart (Dentaurum, Ispringen, Germany), the active self-ligating brackets InOvation™ and InOvation™ mini (GAC, Dentsply Sirona, York, PA, USA) and the passive self-ligating brackets Carrière™ (ODS, Kisdorf, Germany) and BioPassive® (Forestadent, Pforzheim, Germany). The first set-up was athree-point bending test according to DIN EN ISO 15841. For the second experiment, the bracket products glued on amaxilla model were combined with the wire products. The torque moments arising during torqueing of the wires between +20° and -20° were measured in three positions: first incisor, canine and second bicuspid. Bending tests confirmed variation of the force corresponding to the force zones. The nine-strand NiTi wire TurboWireTM and the eight-strand SS wire Multibraid™ did not show any variation dependent on the tested area. Torque-moments generated by the multizone wires were higher compared to the braided wires. The nine-strand NiTi wire showed the lowest moments in spite of the higher dimension. As expected, increasing the interbracket distance reduced the torque moments. The tests verified the existence of multiple force zones in the NiTi wires for forces and moments, respectively. As the torque-moments arising from the multizone wires were rather high, it is not recommended to use these wires as afirst "leveling wire" in orthodontic treatment, especially in extremely crowded cases.

Effects of a ceramic active self-ligating bracket on retraction/tipping/rotation of canine, premolar mesialization, and transverse arch dimensions: A preliminary single-blind split-mouth randomized clinical trial

There is no clinical study on ceramic self-ligating brackets (SLBs). Therefore, this preliminary study was conducted for the first time to address its effects. This split-mouth randomized trial was performed on 32 quadrants in 16 orthodontic patients needing extraction of maxillary premolars and distalization of canines. In each blinded patient, right/left sides were randomized into control (ceramic bracket) and experimental (ceramic SLB) groups. Dental stone models were taken before canine retraction and 3 months into retraction. Models were digitized as three-dimensional models. Changes were measured on superimposed models. Groups were compared using Wilcoxon signed-rank test (α = 0.05, β = 0.1). Both bracket types caused significant changes after 3 months in terms of all assessed clinical outcomes (P ≤ 0.002). Compared to conventional ceramic brackets (control), ceramic SLBs reduced retraction rate (P = 0.001), canine rotation (P = 0.001), canine tipping (P = 0.002), and arch expansion at the canine site (P = 0.003). However, the extents of anchorage loss (P = 0.796) and arch constriction in the premolar area (P = 0.605) were not statistically different between the bracket types. Compared to conventional metal-lined ceramic brackets, active ceramic SLB can increase the duration of canine distalization, while reducing canine rotation and tipping (inducing more bodily movements). The loss of anchorage with ceramic SLB was similar to that of conventional ceramic bracket after 3 months of treatment (considering the lower rate of SLB canine retraction during that time). Both brackets similarly constricted the arch at the premolar site. In the canine area, they expanded the arch, with the SLB causing smaller extents of expansion.

Comparison of frictional coefficient and surface roughness between three different active self-ligating brackets: An experimental in vitro study

Aim: In orthodontic treatment, the high levels of friction may reduce the effectiveness of the mechanical and decrease tooth movement efficiency. The use of active self-ligating brackets is claimed to possibly reduce friction in orthodontic treatment. The aim of this study was to investigate the three-different active self-ligating orthodontic brackets in frictional coefficient and surface roughness. Materials and Methods: This study was true-experiment laboratory with posttest group design to collect the frictional coefficients data from three different active self-ligating brackets. Friction tests were performed on three different active self-ligating brackets—In-Ovation R, Empower, and BioQuick. Each group consists of seven samples of active self-ligating brackets—and stainless steel wire which has been stored in artificial saliva solutions for 14 days. After the friction coefficients of every sample obtained, the bracket clips were separated from the bodies and set on resin acrylic medias. Surface roughness of the bracket clips was evaluated using the atomic force microscope (AFM). A one-way analysis of variance (ANOVA) followed by Scheffe test for comparisons was performed statistically (P < 0.05). Results: BioQuick and Empower orthodontic brackets produced lower frictional coefficients compared to In-Oviation-R brackets. BioQuick showed least frictional coefficients. Based on the statistical analysis, there was no significant difference of frictional coefficients between Empower and BioQuick. Surface roughness test showed that the clip surface of In-Ovation R produced the maximum roughness, followed by Empower and BioQuick. Conclusion: In-Ovation R brackets offered more frictional coefficients and surface roughness than Empower and BioQuick brackets, whereas BioQuick brackets offered the least among all the brackets studied.

Evaluation of friction on self-ligating and conventional brackets associated with different types of archwires submitted to sliding mechanics

Aim: The aim of this study was to verify the frictional force during sliding mechanics in orthodontic tooth movement, using conventional metal brackets of the active and passive self-ligating types with stainless steel and copper nickel titanium archwires. Methods: This experimental in vitro study was conducted with conventional metal (Morelli, Sorocaba, SP, Brazil) brackets, active self-ligated (SLI Morelli, Sorocaba, SP, Brazil) and passive self-ligated (SLP Morelli, Sorocaba, SP, Brazil), with slot 0.022 x 0.028 inches and Roth prescription. The brackets were tested with rectangular section 0.019 x 0.025 inch copper nickel titanium and stainless steel archwires. For each type of bracket, 10 sets of plate/bracket/archwire segment (n=10) were fabricated. Non-parametric Kruskal Wallis and Dunn tests were used for comparison between types of brackets and Wilcoxon tests for comparison between types of archwires. Results: The results showed that the frictional force values were higher with copper nickel titanium than with stainless steel archwires (p&lt;0.05). When copper nickel titanium archwires were used, the active self-ligating brackets showed higher frictional force values than the other types, followed by the conventional brackets. Lower frictional force values were observed with passive self-ligating brackets. For stainless steel archwires, no difference was observed between conventional and active self-ligating brackets, the passive self-ligating type presented lower frictional force values than the others. Conclusion: It was concluded that the higher frictional force was observed when active self-ligating brackets were associated with copper nickel titanium archwires. Lower frictional force was verified between passive self-ligating brackets combined with stainless steel archwires.

Clinical and Salivary Findings in Patients with Metal and Crystalline Conventional and Self-Ligating Orthodontic Brackets.

AimData regarding different types of orthodontic brackets and ligation and various clinical and salivary findings are scarce. Therefore, the aim of this study was to compare clinical and salivary findings in patients with different types of fixed orthodontic appliances.Subjects and methodsDecayed, missing and filled teeth index (DMFT) and plaque index, salivary flow rate, salivary pH and prevalence of white spot lesions were determined in 83 patients with different types of orthodontic brackets and ligation (metal passive self-ligating brackets, conventional metal brackets, mono-crystal brackets and polycrystalline active self-ligating brackets), before and six months after the beginning of fixed orthodontic treatment. The patients were recruited in a private dental office, in the period of two years. The group comprised 83 patients (mean age: 15.14 ± 1.66 years), including 52 women (mean age: 15.08 ± 1.68) and 31 men (15.24 ± 1.64). Statistical analysis was performed by use of dependent and independent samples t-test as well as one way ANOVA, Wilcoxon signed rank test and the Kruskal Wallis test. P-values below 0.05 (p<0.05) were considered significant.ResultsDMFT and salivary flow have shown a significant increase, while salivary pH has shown a significant decrease in the observed time interval, in all patients irrespective of type of brackets and ligation. Among patients with different bracket material, no significant differences were found in any of the observed parameters.ConclusionAlthough salivary flow rate is increased in patients with fixed orthodontic appliances which can have caries-protective effect, DMFT also increases and salivary pH decreases six months after the beginning of the treatment independently of bracket material or ligation type. All patients should receive instructions for precise oral hygiene and dietary habits before the beginning of fixed orthodontic therapy and at every dental check-up.

Comparison of transverse maxillary dental arch width changes with self-ligating and conventional brackets in patients requiring premolar extraction – A randomised clinical trial

The purpose of this study was to evaluate, the change in the transverse maxillary arch dimensions, in patients requiring all first premolar extractions when using Active and Passive Self-ligating brackets, and comparing them with Conventional brackets. This study was a non-blinded randomised clinical trial, which consisted of 42 patients (21 males and 21 females) within the age group of 16-25 years, having bimaxillary protrusion. They were divided into three groups with 14 patients each. In Group 1-Conventional brackets (3M Unitek), in Group 2-Passive Self-ligation brackets: Smart Clip (3M Unitek), and in Group 3-Active Self-ligation brackets: Empower AO (American Orthodontics) were bonded. All brackets had MBT prescription and 0.02" slot size. Dental study models were taken before the start of treatment and after six months of retraction. Inter-canine and intermolar widths were measured in all the three groups in the above mentioned stages. As compared to Conventional brackets, Self-ligating brackets (Passive and Active) showed greater increase in the transverse arch widths. Furthermore, between Passive and Active Self-ligating brackets, Passive Self-ligating brackets-Smart Clip (Group 2) showed a greater increment in the transverse arch dimensions, with an increase of 4.89mm in the inter-canine width and 3.4mm in intermolar width. Significant difference was found between Self-ligating brackets and the Conventional bracket system regarding maxillary arch width dimensional changes. Passive Self-ligating brackets-Smart Clip (Group 2) showed the highest and inter-molar width increase.

A Comparative in vitro Investigation of the Frictional Resistance produced by Active Self-Ligating Brackets, Passive Self-Ligating Brackets and Low Friction Ligatures

A Comparative in vitro Investigation of the Frictional Resistance produced by Active Self-Ligating Brackets, Passive Self-Ligating Brackets and Low Friction Ligatures

Alveolar bone changes and root resorption concomitant with rectangular NiTi in initial leveling and alignment

Introduction: Fixed orthodontic appliances include a wide variety of archwires used as a means of delivering forces on teeth. As there are a variety of available archwires, it is important to know which is the most efficient during the initial aligning stage of the treatment. During the initial phase of orthodontic treatment, the use of rectangular arch wires has been reported to result in decreased incisor inclination compared to the traditional round NiTi arch wires. Debates still exist regarding the effect of SLB on the alveolar bone and the root length. Aim of the study: The aim of this clinical study is to evaluate the changes in the alveolar bone and the root resorption during initial leveling and alignment with rectangular NiTi arch wires. Materials and methods: The current randomized clinical prospective study was conducted on a total sample of 20 patients, divided into two groups of ten. Group I consisted of 10 patients treated with active self-ligating stainless-steel brackets and round Cu NiTi wires using the conventional sequence for leveling and alignment. Group II consisted of 10 patients treated with active self-ligating stainless-steel brackets and rectangular Cu NiTi archwires for leveling and alignment. CBCTs were taken after achieving the study objectives (post leveling and alignment) to be used for analyzing the study measurements and comparison with the pretreatment CBCT data. Both groups were compared regarding alveolar bone length, alveolar bone thickness and root length. Conclusion: We concluded that there was no significant difference between the two groups concerning alveolar bone length and thickness. However, group II (treated with rectangular Cu NiTi archwires) showed a significant decrease in root length.

Frictional resistance of different types of self-ligating brackets with different wire combinations

The purpose of this study was to compare the effect of the mode of ligation on the frictional resistance of ceramic brackets and the effect of the bracket material on the frictional resistance whether it is static or kinetic. To achieve this one passive self-ligating ceramic bracket (Damon Clear 2), one active self-ligating ceramic bracket (Empower Clear) in addition to one passive self-ligating metal bracket (Damon Q) were used. These brackets were coupled with two sizes of stainless steel (SS) archwires (0.017 x 0.025-in and 0.019 x 0.025-in). A universal testing machine was used to pull the brackets along the straight distal end of the wire segments at a crosshead speed of 5 mm/min over a distance of 8 mm/min. The test was undergone under dry conditions. The results showed that the passive self-ligating brackets (PSLB) had significantly lower static friction (SF) and kinetic friction (KF) than the active self-ligating bracket (ASLB) with no significant differences between the ceramic and metal PSLB’s. Also inceasing wire size increased the SF and KF for the PSLB’s but did not affect the ASLB significantly.

Comparison of the efficacy of tooth alignment among lingual and labial brackets: an in vitro study.

The aim of this study was to evaluate the efficacy of tooth alignment with conventional and self-ligating labial and lingual orthodontic bracket systems. We tested labial brackets (0.022″ slot size) and lingual brackets (0.018″ slot size). The labial brackets were: (i) regular twin brackets (GAC-Twin [Dentsply]), (ii) passive self-ligating brackets including (Damon-Q® [ORMCO]; Ortho classic H4™ [Orthoclassic]; FLI®SL [RMO]), and (iii) active self-ligating brackets (GAC In-Ovation®C [DENTSPLY] and SPEED™[Strite]). The lingual brackets included (i) twin bracket systems (Incognito [3M] and Joy™ [Adenta]), (ii) passive self-ligating bracket system (GAC In-Ovation®LM™ [Dentsply]), and (iii) active self-ligating bracket system (Evolution SLT [Adenta]). The tested wires were Thermalloy-NiTi 0.013″ and 0.014″ (RMO). The archwires were tied to the regular twin brackets with stainless steel ligatures 0.010″ (RMO). The malocclusion simulated a displaced maxillary central incisor in the x-axis (2 mm gingivally) and in the z-axis (2 mm labially). The results showed that lingual brackets are less efficient in aligning teeth when compared with labial brackets in general. The vertical correction achieved by labial bracket systems ranged from 72 to 95 per cent with 13″ Thermalloy wires and from 70 to 87 per cent with 14″ Thermalloy wires. In contrast, the achieved corrections by lingual brackets with 13″ Thermalloy wires ranged between 25-44 per cent and 29-52 per cent for the 14" Thermalloy wires. The anteroposterior correction achieved by labial brackets ranged between 83 and 138 per cent for the 13″ Thermalloy and between 82 and 129 per cent for the 14″ Thermalloy wires. On the other hand, lingual brackets corrections ranged between 12 and 40 per cent for the 13″ Thermalloy wires and between 30 and 45 per cent for the 14″ Thermalloy wires. This is a lab-based study with different labial and lingual bracket slot sizes (however they are the commonly used ones in clinical orthodontics) and study did not consider saliva, periodontal ligament, mastication and other oral functions. The effectiveness of lingual brackets in correcting vertical and anteroposterior displacement achieved during the initial alignment phase of orthodontic treatment is lower than that of the effectiveness of labial brackets.

Mandibular dental arch changes with active self-ligating brackets combined with different archwires.

The aim was to compare mandibular arch and incisor inclinational changes by comparing active self-ligating brackets used with different forms of archwires with a control group in nonextraction cases. The sample of 50 patients with Class I malocclusion was divided into three groups: Group I was treated with active self-ligating brackets (Nexus, Ormco/Orange, CA, USA) used with Damon arch form copper nickel-titanium (Cu-NiTi) and stainless steel (SS) wires; Group II was treated with interactive self-ligating bracket system (Empower, American Orthodontics, Sheboygan, Wis, USA) used with standard Cu-NiTi and SS wires; and Group III was treated with Roth prescribed conventional brackets (Forestadent, Pforzheim, Germany) with standard Cu-NiTi and SS wires which was designed as a control group. Changes in dimension of mandibular arch and inclination of incisors were assessed on dental models and lateral cephalometric radiographs at pretreatment (T1) and posttreatment (T2) periods. Paired-t test and one-way analysis of variance were used to perform intragroup and intergroup comparisons, respectively. In all groups, an average increase of transversal distances occurred from pretreatment to the posttreatment period (P < 0.05). However, mandibular arch length increase was significantly different among the Groups I-III (P = 0.008) and I-II (P = 0.006). No significant intergroup difference was found with regard to incisor inclinational changes. Bracket type had no significant effect on the mandibular dimensional or incisor inclination changes. Besides this, archwire type had only little effect on the treatment results as active self-ligating bracket with Damon archwires increased mandibular arch length greater than other groups.

Frictional resistance of active and passive aesthetic self-ligating brackets with different orthodontic wire sizes

The purpose of this study was toinvestigate the effect of passive and active Self-ligation of aesthetic brackets on the static and kinetic friction with different wire sizes. Two types of ceramic brackets were used; Empower Clear (active self-ligatingbracket (ASLB)) and Damon Clear 2 (passive self-ligating bracket (PSLB)). They were coupled with 0.017 x 0.025-in and 0.019 x 0.025-in stainless-steel (SS) wires. A universal testing machine was used to pull the brackets along the distal end of the archwire. The test was performed at 5 mm/min crosshead speed over a distance of 8 mm to measure the static friction (SF) and the kinetic friction (KF) under dry conditions. The results showedthe PSLB’s to have significantly lower SF and KF with both wire sizes.

Force level of small diameter nickel-titanium orthodontic wires ligated with different methods

BackgroundThe aim of this study was to compare the deflection force in conventional and thermally activated nickel-titanium (NiTi) wires in passive (Damon Q) and active (Bioquick) self-ligating brackets (SLB) and in conventional brackets (CB) tied by two different methods: elastomeric ligature (EL) and metal ligature (ML).MethodsTwo wire diameters (0.014 and 0.016 in.) and 10 specimens per group were used. The specimens were assembled in a clinical simulation device and tested in an Instron Universal Testing Machine, with a load cell of 10 N. For the testing procedures, the acrylic block representative of the right maxillary central incisor was palatally moved, with readings of the force at 0.5, 1, 2, and 3 mm, at a constant speed of 2 mm/min and temperature of 36.5 °C.ResultsThe conventional NiTi released higher forces than the thermally activated NiTi archwires in large deflections. In general, the SLB showed lower forces, while the ML had higher forces, with both showing a similar force release behavior, constantly decreasing as the deflection decreased. The EL showed an irregular behavior. The active SLB showed smaller forces than passive, in large deflections.ConclusionsThe SLB and the ML exhibit standard force patterns during unloading, while the elastomeric ligatures exhibit a randomly distributed force release behavior.