Rectangular Stainless Steel Wires Research Articles

Effectiveness of methods for cleaning arch wire: an in vitro study

The aim of this study was to evaluate various methods of removing bacterial and fungus biofilm, to simulate orthodontic arch wires cleaning before reinsertion in the patients appliance. Rectangular Nickel Titanium (NiTi), Stainless Steel (SS) and Titanium Molybdenum (TMA) wires were divided into five groups, then contaminated with strains of Streptococcus mutans and Candida albicas. Four segments of each group served as control and were not contaminated. Six cleanings methods were used to remove the biofilm: cotton roll and a chemical agent (chlorhexidine, sodium hypochlorite, 70% alcohol), cotton roll and water, steel woll and immersion on enzymatic detergent. There was a control group not decontaminated Then wires were placed in broth separately, and after an incubation period the optical density (OD) was measured, observing whether there was microbial growth. A wire segment of each subgroup of SS 3M® was taken to the Scanning Electron Microscope (SEM) for visualization of the treatment response. The results were submitted to one-way ANOVA test and Tukey post-test. With the exception of 70% alcohol, the disinfection means behaved similarly regardless the type of wire. Two percent Chlorhexidine and 1% Sodium Hypochlorite totally removed the microorganisms while other agents left a high microbial concentration. Chemical cleaning is necessary to remove biofilm in orthodontic wires; 1% Sodium Hypochlorite and 2% Chlorhexidine are good disinfectants for this purpose.

“AN EFFECT OF TWO COMMERCIALLY AVAILABLEDENTRIFICES ON NICKEL-TITANIUM AND STAINLESS STEEL ORTHODONTIC ARCHWIRES: AN IN-VITRO STUDY”

Aim The study aimed to evaluate the effect of two commercially available dentifrices on Nickel-Titanium and Stainless Steel orthodontic arch wires. Methods A total of 33 rectangular NiTi (0.019” x 0.025”) and 33 rectangular Stainless Steel (0.019” x 0.025”) wires were taken for this study. Each group containing 16 wires were treated with the following dentifrices; Group A - Colgate Strong Teeth Toothpaste Group B – PatanjaliDantKanti Toothpaste when mounted on typhodont with help of power toothbrush. the sample were scanned under Stereo Microscope at 35x magnification and Scanning Electron Microscope at 500x magnification to check whether the dentifrices have deleterious effects on the orthodontic arch wires. The recorded data was tabulated in MS-Excel and analyzed using one-way ANOVA. Statistical analysis was performed using SPSS statistical software at the 0.05 significance level. Descriptive statistics were done using the paired t- test for the intra group comparison and unpaired t- test for the inter group comparison. Results The SEM surface analysis revealed that the most surface variations were seen with the Stainless Steel arch wires treated with the Group A toothpaste followed by the Stainless steel wires treated with the Group B toothpaste. Both the groups demonstrated depressions, pores, furrows or grains in 1/3rd of the surface of the arch wire. However, the dimensions of the depressions, pores furrows was greater in the wires treated with Group A toothpaste when compared to the Group B toothpaste. Also, with the NiTiarchwires treated with the Group A toothpaste showed more surface variation compared to the NiTi wires treated with the Group B toothpaste. Both the groups demonstrated depressions, pores, furrows or grains in 1/3rd of the surface of the archwire. However, the dimension of the depressions, pores, furrows was greater in the wires treated with Group A toothpaste when compared to then Group B toothpaste. Conclusion The stainless steel archwires exhibited the maximum alterations in surface topography after treatment with both the dentifrices when compared to the Nickel-Titanium wires.

Assessment of minimum force required to initiate sliding of stainless steel wire in ceramic (monocrystalline and polycrystalline) and stainless steel preadjusted edgewise brackets using stainless steel and elastomeric ligation techniques – An in vitro study

Objectives: To compare the force required to initiate sliding of rectangular stainless steel wire in monocrystalline ceramic bracket v/s polycrystalline ceramic bracket v/s stainless steel bracket using stainless steel ligation technique and to compare the force required to initiate sliding of rectangular stainless steel wire in monocrystalline ceramic bracket v/s polycrystalline ceramic bracket v/s stainless steel bracket using elastomeric ligation technique. Methods: The archwire was pulled in a vertical direction by the testing machine, until the resistance was overcome and the archwire started to slide through the bracket. The force to overcome resistance and to initiate sliding of the archwire was measured. Results: In metal brackets, there is minimum resistance to sliding as compared to the two different ceramic brackets. Among the two ceramic brackets polycrystalline bracket offered more resistance to sliding then monocrystalline bracket. Although SS ligation offered less resistance to sliding then elastomeric ligation in all three bracket types, the difference between the two ligation systems is not statistically significant. Conclusions: In maximum anchorage cases metal bracket along with SS ligation should be used to reduce the frictional resistance, enabling the use of lighter forces and eventually conserving the anchorage.

Micrographic evaluation of different widia compositions of orthodontic pliers submitted to peracetic acid and intensive use

Abstract Introduction The sterilization and disinfection procedures should be adapted to the chemical profile of the metal alloys present in the instruments. Objective This study aimed to perform a micrographic assessment on the surface characteristics of the widia of orthodontic pliers with two alloy compositions subjected to the action of 0.2% peracetic acid and intensive use. Material and method Twenty distal cutting pliers were divided into two groups (n=10) according to widia composition (%wt): W1- 85% to 87% of tungsten carbide (TC) and other components in the proportion of 13% to 15% and W2 – 87.5% to 88.5% of tungsten carbide and 11.5% to 12.5% for other components. All the pliers were assessed in a stereoscopic magnifying glass (32x) after three treatments: before use (T0); after cutting 100 segments of rectangular stainless-steel wires – intensive use (T1); and after 100 sterilization cycles in 0.2% peracetic acid and intensive use (T2). The cutting sites of all pliers were standardized. Widia regions were defined by line “A” representing T1 and line “B” representing T2. A frequency distribution table and Fisher’s exact test (α=0.05) was performed. We assessed two widia from each composition and treatment in SEM and energy-dispersive X-ray spectroscopy (EDS/SEM). Result The results showed that W1 pliers presented significantly fewer defects after the sterilization cycles with peracetic acid and intensive use than W2 pliers (p=0.0198). There were no differences between both pliers after intensive use (p=1.000). Conclusion The SEM images and EDS analyses showed changes in widia surfaces after the different treatments. Widia composition affected the resistance of the orthodontic pliers after sterilization cycles with 0.2% peracetic acid and intensive use.

Increased buccolingual dimension of maxillary second premolar bracket : Is it necessary ?

Introduction : Small-sized maxillary second premolars pose a challenge for the orthodontist with regards to alignment of the contact point with the maxillary first molar. To overcome this discrepancy, Dentaurum Discovery Smart brackets have been developed with thicker buccopalatal dimension. Aim of the study : The aim of this study was to compare between two bracket systems (Dentaurum Discovery Smart) and conventional (American Orthodontics/Ormco) brackets regarding the effect of differential in-out buccopalatal thickness on the alignment of the contact points of maxillary premolars and molars as well as bond failure rate. Materials and Methods : This prospective study consisted of 24 patients with an age range of 20-30 years old and a mean age of 24.5 years selected from a private practice in Cairo, Egypt. The patients had full permanent dentition and were non-syndromic with no previous orthodontic treatment. At least one maxillary second premolar had a reduced buccopalatal dimension. The patients were randomly divided into two groups, each group containing 12 patients. Group 1 were treated with Discovery smart Dentaurum brackets and Group 2 were treated with American Orthodontics /Ormco mini diamond brackets. Treatment was continued with fixed appliances for 2 years until rectangular stainless steel wires were reached. Results : There was a statistically significant difference between Group 1 and Group 2 regarding proximal contact point discrepancy (P<0.05) with 50% of Group 2 having at least 0.5 mm buccal contact point discrepancy between upper second premolar and upper permanent first molar. No contact point discrepancy was observed for Group 1 (0%). However bond failure rate was significantly higher in Group 1 (80%) compared to (20%) in Group 2. Conclusions : The Dentaurum Discovery Smart brackets are highly effective in achieving adequate buccopalatal alignment of small sized maxillary second premolars with maxillary first premolars and permanent first molars. However they have the drawback of frequent bond failures due to their thicker buccopalatal dimension.

Evaluation and Comparison of Two Different Mouthwashes on Frictional Resistance Between Orthodontic Bracket and Archwire: An in Vitro Study

Aims: This study aimed to evaluate and compare the effect of tea tree oil (TTO) mouthwash and chlorhexidine (CHX) mouthwash on frictional resistance. Settings and Design: In vitro. Materials and Methods: In total, 60 extracted premolars were mounted on a custom-made acrylic fixture. These 60 premolars were randomly divided into 3 groups of 20 each, on which 0.022″ × 0.028″ slot MBT stainless steel brackets were bonded and 0.019″ × 0.025″ rectangular stainless steel wire was ligated with an elastomeric module. The 3 groups included a control group where the samples were immersed in artificial saliva and 2 experimental groups immersed in 0.2% CHX and TTO mouthwash, respectively, for 1.5 hours. Postimmersion static frictional resistance was evaluated on a universal testing machine at crosshead speed of 0.5 mm/min. Statistical Analysis Used: Tukey’s post hoc procedure. Results: This study showed a statistically significant difference in the frictional resistance between saliva and CHX groups and CHX and TTO groups ( P &lt; .05). No statistically significant difference was observed between saliva and TTO groups ( P &gt; .05). The frictional resistance was more in the CHX mouthwash group than in the TTO mouthwash group. Conclusions: Frictional resistance was lesser in the TTO mouthwash than in the CHX mouthwash. Based on this result, TTO mouthwash can be used instead of CHX mouthwash as an oral hygiene aid in patients with orthodontic treatments.

Effect of archwire stiffness and friction on maxillary posterior segment displacement during anterior segment retraction: A three-dimensional finite element analysis.

ObjectiveSliding mechanics using orthodontic miniscrews is widely used to stabilize the anchorage during extraction space closure. However, previous studies have reported that both posterior segment displacement and anterior segment displacement are possible, depending on the mechanical properties of the archwire. The present study aimed to investigate the effect of archwire stiffness and friction change on the displacement pattern of the maxillary posterior segment during anterior segment retraction with orthodontic miniscrews in sliding mechanics.MethodsA three-dimensional finite element model was constructed. The retraction point was set at the archwire level between the lateral incisor and canine, and the orthodontic miniscrew was located at a height of 8 mm from the archwire between the second premolar and first molar. Archwire stiffness was simulated with rectangular stainless steel wires and a rigid body was used as a control. Various friction levels were set for the surface contact model. Displacement patterns for the posterior and anterior segments were compared between the conditions.ResultsBoth the anterior and posterior segments exhibited backward rotation, regardless of archwire stiffness or friction. Among the conditions tested in this study, the least undesirable rotation was found with low archwire stiffness and low friction.ConclusionsPosterior segment displacement may be unavoidable but reducing the stiffness and friction of the main archwire may minimize unwanted rotations during extraction space closure.

The resistance to axial dislodgement of nickel titanium compression arch wire hooks – an in vitro study

Abstract Objective To evaluate the level of force required to axially dislodge nickel titanium compression hooks (Trillium Compression HookTM, Hespeler Orthodontics) placed on orthodontic arch wires in vitro. Materials and methods Nickel titanium compression hooks were placed on arch wires with a specially designed pair of pliers. The resistance to axial dislodgement was tested on a total of 260 hooks placed in a standardised way on round (0.016″, 0.018″, 0.020″), square (0.020 × 0.020″) and rectangular (0.016 × 0.022″, 0.019 × 0.025″, 0.021 × 0.025″) stainless steel (Rocky Mountain Orthodontics), nickel titanium, or β-titanium (Hespeler Orthodontics) arch wires. The forces required to displace the hooks were recorded using an Instron tensile testing machine. The data were compared with the results reported in similar studies on stainless steel crimpable arch wire hooks. Results The forces required to dislodge the compression hooks varied between 45.0 N and 161.9 N. The hook’s resistance to dislodgement was found to be high in all tested hook/wire combinations. The lowest recorded average dislodging force was found in the 0.020″ nickel titanium group and the highest average force was in the 0.016 × 0.022″ β-titanium group. Conclusion The forces needed to dislodge the tested nickel titanium compression arch wire hooks exceed the force levels previously reported for stainless steel crimpable arch wire hooks.

Comparison of Frictional Resistance in Conventional Brackets with Different Stainless Steel Wires

The aim of the study was to evaluate and compare static and kinetic friction of round (0.018") and rectangular (0.019 × 0.025") stainless steel (SS) wires of different brands with conventional preadjusted edgewise brackets. Maxillary canine and two bicuspids of 0.022 × 0.028" slot sized MBT prescription (Gemini, 3M Unitek, Monrovia, California) brackets were chosen. The wires selected were 0.018" SS (3M Unitek); 0.018" Australian wire (AJ Wilcock, UK), and 0.019 × 0.025" SS (3M Unitek). The testing was done on Instron 3382. A total of 30 test combinations with three wires were repeated 10 times. The static and kinetic friction was recorded in Newton. The kinetic friction was also recorded in Newton at 3, 5, 7, and 9 mm of movement. One-way analysis of variance (ANOVA) and descriptive statistics were used for comparing the friction. To test the level of significance, multiple comparisons were used within wire in bracket by using post hoc test. Static friction was found to be greater than kinetic in all wires; 0.018" SS (3M) wire exhibited minimum static and kinetic friction; while 0.019 × 0.025" SS (3M) exhibited maximum static friction. Kinetic friction was similar in both 0.018" AJ Wilcock and 0.019 × 0.025" SS but greater than 0.018" SS (3M). Least static and kinetic friction was exhibited by 0.018" SS (3M). Kinetic friction was similar in both 0.018" AJ Wilcock and 0.019 × 0.025" SS. The study concluded that 0.018" SS (3M) is better for individual canine retraction than the other wires used in the study because it has the least frictional resistance; 0.019 × 0.025" SS (3M) is a better wire for canine retraction than 0.018" AJ Wilcock as we can have a three-dimensional control over tooth movement. When torque control is not a prime requisite, then 0.018" SS (3M) can be used for retraction of incisors instead of 0.018" AJ Wilcock in severely proclined incisor cases.

PENGGUNAAN PIR T-LOOP UNTUK PERBAIKAN I GIGI MOLAR KEDUA PERMANEN RAHANG BAWAH

Background: Mesial tipping of permanent molar could be corrected by many ways. One of the simplest way was by using T-loop spring. Objective: To report the result of using straight wire appliance system Roth with ¬T-loop spring in order correction of mesial tipping of second lower permanent molar on both side.Case Management: A 35 years old woman came with chief complain wanted to fx the lower left and right molar which was tilted and felt uncomfortable during mastication. OPG examination showed a mesial tipping of 37 and 47 tooth with 300 and 550 angulations. The measurement of angulations was using modifcation of the midline reference plane as used by Elsey and Rock. The straight wire appliance system Roth with .022” slot was used for the treatment. T-loop spring with .018x.022” rectangular stainless steel wire was used to upright of both second permanent molars. Observation of 4 months treatment using T-loop spring showed an improvement in angulations of both second molars; 550 on 37 and 630 on 47.Conclusion: Mesial tipping correction of second permanent molar can beaccomplished using T-loop spring with stainless steel rectangular .018x.022” wire and consistently yields satisfactory result.

Evaluating the Surface Characteristics of Stainless Steel, TMA, Timolium, and Titanium-niobium Wires: An in vivo Scanning Electron Microscope Study.

Recent metallurgical research and advancement in material science has benefited orthodontists in the selection of an appropriate wire size and alloy type, which is necessary to provide an optimum and predictable treatment results. The purpose of the study was to clinically evaluate and compare the surface characteristics of 16 x 22 stainless steel, Titanium molybdenum alloy, timolium, and titanium-niobium before and after placing them in a patient's mouth for 3 months using a scanning electron microscope (SEM). The total sample size was 40, which were divided into four groups (group 1 - stainless steel wires, 10 samples, group 2 - TMA wires, 10 samples, group 3 - timolium wires, 10 samples, and group 4 - titanium-niobium wires, 10 samples), and these were further subdivided into 5 each. The first subgroup of five samples was placed in the patient's mouth and was evaluated under SEM, and another subgroup of five samples was directly subjected to the SEM. Scanning electron microscopic evaluation of surface characteristics of unused 16 x 22 rectangular stainless steel wire under 500 x magnification showed an overall smooth surface. Stainless steel wire samples placed in the patient's mouth showed black hazy patches, which may be interoperated as areas of stress. TMA unused wires showed multiple small voids of areas and small craters with fewer elevated regions. The TMA wire samples placed in the patient's mouth showed black hazy patches and prominent ridges, making the wire rougher. Timolium unused archwires showed heavy roughness and voids, whereas wires tested in the patient's mouth showed homogeneous distribution of deep cracks and craters. Unused titanium-niobium archwires showed uniform prominent striations and ridges with occasional voids, whereas wires used in the patient's mouth showed prominent huge voids that could be interpreted as maximum stress areas. Stainless steel (group 1) used and unused wires showed smooth surface characteristics when compared with all the other three groups followed by timolium, which was superior to titanium-niobium wires and TMA wires. Timolium wires are superior to titanium-niobium wires and TMA wires.

Study on the frictional properties between bracket and wire by sandblast processing

PurposeVarious techniques are employed during orthodontic treatment involving anchorage units and multi-bracket apparatus. We investigated the efficacy of such techniques by examining the frictional force they created between the wire and bracket using a pulling test. Materials and methodsIn order to examine how the frictional force between the wire and bracket varied between operators and ligature types, 0.010in. stainless steel orthodontic ligature wires (ligature wires) and orthodontic elastic modules (ligature modules) were used five times each by 11 orthodontists, and the resultant frictional force created between the wire and bracket was measured with a pulling test.To compare the effects of sandblast processing on the frictional force between the bracket and wire, each of the following four types of orthodontic wires was used five times: 0.016in. round stainless steel wire, 0.016in. round nickel titanium wire, 0.017×0.025in. rectangular stainless steel wire, and 0.017×0.025in. rectangular nickel titanium wire. ResultsThe ligature modules exhibited significantly lower frictional force than the ligature wires. The frictional force in ligature modules also was more stable than in the ligature wire among the assessments of inter-operator and intra-operator. All of the wire types demonstrated significantly greater frictional force after being sandblasted. ConclusionThese results indicate that the applying of wire with sandblast processing and ligature modules can reinforce the anchorage units used for tooth movement by increasing the stable frictional force between the bracket and wire.

A comparative study of frictional force in self-ligating brackets according to the bracket-archwire angulation, bracket material, and wire type.

ObjectiveThis study aimed to compare the frictional force (FR) in self-ligating brackets among different bracket-archwire angles, bracket materials, and archwire types.MethodsPassive and active metal self-ligating brackets and active ceramic self-ligating brackets were included as experimental groups, while conventional twin metal brackets served as a control group. All brackets were maxillary premolar brackets with 0.022 inch [in] slots and a -7° torque. The orthodontic wires used included 0.018 round and 0.019 × 0.025 in rectangular stainless steel wires. The FR was measured at 0°, 5°, and 10° angulations as the wire was drawn through the bracket slots after attaching brackets from each group to the universal testing machine. Static and kinetic FRs were also measured.ResultsThe passive self-ligating brackets generated a lower FR than all the other brackets. Static and kinetic FRs generally increased with an increase in the bracket-archwire angulation, and the rectangular wire caused significantly higher static and kinetic FRs than the round wire (p < 0.001). The metal passive self-ligating brackets exhibited the lowest static FR at the 0° angulation and a lower increase in static and kinetic FRs with an increase in bracket-archwire angulation than the other brackets, while the conventional twin brackets showed a greater increase than all three experimental brackets.ConclusionsThe passive self-ligating brackets showed the lowest FR in this study. Self-ligating brackets can generate varying FRs in vitro according to the wire size, surface characteristics, and bracket-archwire angulation.

Reduction in static friction by deposition of a homogeneous diamond-like carbon (DLC) coating on orthodontic brackets.

In orthodontics, a reduction in static friction between the brackets and wire is important to enable easy tooth movement. The aim of this study was to examine the effects of a homogeneous diamond-like carbon (DLC) coating on the whole surfaces of slots in stainless steel orthodontic brackets on reducing the static friction between the brackets and the wire. The DLC coating was characterized using Raman spectroscopy, surface roughness and contact angle measurements, and SEM observations. Rectangular stainless steel and titanium-molybdenum alloy wires with two different sizes were employed, and the static friction between the brackets and wire was measured under dry and wet conditions. The DLC coating had a thickness of approximately 1.0 μm and an amorphous structure was identified. The results indicated that the DLC coating always led to a reduction in static friction.

Photoelastic analysis of stress generated by wires when conventional and self-ligating brackets are used: a pilot study.

OBJECTIVE: By means of a photoelastic model, this study analyzed the stress caused on conventional and self-ligating brackets with expanded arch wires. METHOD: Standard brackets were adhered to artificial teeth and a photoelastic model was prepared using the Interlandi 19/12 diagram as base. Successive activations were made with 0.014-in and 0.018-in rounded cross section Nickel-Titanium wires (NiTi) and 0.019 x 0.025-in rectangular stainless steel wires all of which made on 22/14 Interlandi diagram. The model was observed on a plane polariscope - in a dark field microscope configuration - and photographed at each exchange of wire. Then, they were replaced by self-ligating brackets and the process was repeated. Analysis was qualitative and observed stress location and pattern on both models analyzed. CONCLUSIONS: Results identified greater stress on the region of the apex of premolars in both analyzed models. Upon comparing the stress between models, a greater amount of stress was found in the model with conventional brackets in all of its wires. Therefore, the present pilot study revealed that alignment of wires in self-ligating brackets produced lower stress in periodontal tissues in expansive mechanics.

Effect of time and pH on physical-chemical properties of orthodontic brackets and wires.

To test the hypothesis that treatment time, debris/biofilm, and oral pH have an influence on the physical-chemical properties of orthodontic brackets and arch wires. One hundred twenty metal brackets were evaluated. They were divided into four groups (n = 30) according to treatment time: group C (control) and groups T12, T24, and T36 (brackets recovered after 12, 24, and 36months of treatment, respectively). Rectangular stainless-steel arch wires that remained in the oral cavity for 12 to 24months were also analyzed. Dimensional stability, surface morphology, composition of brackets, resistance to sliding of the bracket-wire set, surface roughness of wires, and oral pH were analyzed. One-way analysis of variance, followed by a Tukey multiple comparisons test, was used for statistical analysis (P < .05). Carbon and oxygen were shown to be elements that increased expressively and in direct proportion to time, and there was a progressive increase in the coefficient of friction and roughness of wires as a function of time of clinical use after 36months. Oral pH showed a significant difference between group T36 and its control (P = .014). The hypothesis was partially accepted: treatment time and biofilm and debris accumulation in bracket slots were shown to have more influence on the degradation process and frictional force of these devices than did oral pH.

Frictional Resistance of Three Types of Ceramic Brackets

ABSTRACTObjectivesTo investigate the static frictional resistance at the bracket/archwire interface in two recently introduced bracket systems and compare them to conventional ceramic and conventional metal bracket systems. Three variables were considered including the bracket system, archwire type and archwire angulation.Material and MethodsFour bracket systems were tested in vitro: Self ligating ceramic, ceramic with metal slot and module, conventional ceramic with module and conventional metal with module. A specially constructed jig and an Instron testing machine were used to measure the static frictional resistance for 0.014 inches round and 0.018 x 0.025 inches rectangular stainless steel wires at 0° and 7° angulations. Main outcome measures: static frictional force at the bracket/archwire interface; recorded and measured in units of force (Newtons).ResultsSelf ligating ceramic and metal slot ceramic bracket systems generated significantly less static frictional resistance than conventional ceramic bracket systems with the wire at both angulations (P < 0.05). Changing the wire from 0.014 round to 0.018 x 0.025 rectangular wire significantly increased frictional forces for metal slot ceramic and conventional metal bracket systems (P < 0.01). Increasing wire angulation significantly increased frictional resistance at the bracket/archwire interface for all four types of bracket systems tested (P < 0.001).ConclusionsCompared to conventional ceramic, self ligating ceramic and metal slot ceramic bracket systems should give improved clinical performance, matching that of conventional metal brackets.

Evaluation of the friction force generated by monocristalyne and policristalyne ceramic brackets in sliding mechanics

To evaluate and compare "in vitro" the maximum friction force generated by three types of esthetic brackets, two types of polycrystalline conventional ceramic brackets (20/40 and InVu) and one type of sapphire monocrystalline bracket (Radiance) in dry and artificial saliva wet settings. Also, to evaluate the influence exerted by artificial saliva on the friction forces of those brackets. Tests were performed in dry and artificial saliva wet setting (Oral Balance) by using an EMIC DL 10000 testing machine, simulating a 2 mm slide of 0.019 x 0.025-in rectangular stainless steel wires over the pre-angulated and pre-torqued (right superior canine, Roth prescription, slot 0.022 x 0.030-in) brackets (n = 18 for each bracket). In order to compare groups in dry and wet settings, the ANOVA was used. For comparisons related to the dry versus wet setting, the student t test was used for each group. The results showed that in the absence of saliva the Radiance monocrystalline brackets showed the highest friction coefficients, followed by the 20/40 and the InVu polycrystalline brackets. In tests with artificial saliva, the Radiance and the 20/40 brackets had statistically similar friction coefficients and both were greater than that presented by the InVu brackets. The artificial saliva did not change the maximum friction force of the Radiance brackets, but, for the others (20/40 and InVu), an increase of friction was observed in its presence. The InVu brackets showed, in the absence and in the presence of saliva, the lowest friction coefficient.

Onychophagia and postorthodontic isolated gingival recession: Diagnosis and treatment

This clinical report describes the diagnosis and the management of isolated-type recession defects of complex etiology in 2 healthy postorthodontic patients. The lesions were confined to 1 mandibular incisor and were associated with an abnormal buccolingual inclination of the affected tooth despite a lingual retainer made with a round stainless steel twisted wire. After careful questioning, it was determined that the recession defects were indirect effects of habitual onychophagia. The concomitant fingernail-biting habit and the lingual bonded retainer led to the indirect development of bone dehiscence and, consequently, gingival recession.

Frictional Characteristics of Active and Passive Self-Ligation Bracket Systems:An in vitro Study

Self-ligating brackets are ligatureless bracket systems which are gaining immense popularity in contemporary orthodontics. Compared with conventional appliances, self-ligating mechanisms attribute their increased efficiency and reduced treatment time to their improved frictional characteristics. Aim: The present study was conducted to evaluate the kinetic frictional resistance of four self-ligating brackets: Two active types, (SpeedTM and In-Ovation® R) two passive types (Damon 3 and SmartClip) and compare them with conventional brackets ligated with elastomeric module. The brackets were tested against five different dimensions of round and rectangular stainless steel wires (0.018, 0.020, 0.017 × 0.025, 0.019 × 0.025, 0.021 × 0.025).