Impulse debracketing compared to conventional debonding: Extent of enamel damage,adhesive residues and the need for postprocessing

Objective:To evaluate impulse debonding compared to three conventional methods for bracket removal in relation to the damage caused to the enamel surface.Materials and Methods:Ninety-six osteotomed third molars were randomly assigned to two study groups (n  =  48) for bracket bonding with either a composite adhesive system (CAS) or a glass-ionomeric cement (GIC). These two groups were then each randomly divided into four subgroups (n  =  12) according to the method of debonding using (1) bracket removal pliers, (2) a side-cutter, (3) a lift-off debracketing instrument, or (4) an air pressure pulse device. Following debonding and corresponding postprocessing with either a finishing bur (CAS) or ultrasound (GIC), the enamel surfaces were assessed for damage, adhesive residues, and the need for postprocessing using scanning electron microscopy and the Adhesive Remnant Index, and the surfaces were compared in terms of mode of removal and type of adhesive using Fisher''s exact test (α  =  5%).Results:No significant differences were found between the two different types of adhesives (CAS, GIC) in terms of the amount of damage to the enamel. Portions of enamel damage were found for impulse debonding/0%<bracket removal pliers/4%<lift-off debracketing instrument/17%<side-cutter/21%. The highest Adhesive Remnant Index grades were seen for impulse debonding. GIC residues after postprocessing using ultrasound were seen in 79%, compared to 48% after rotational postprocessing of CAS residues.Conclusions:Impulse debonding provides a good alternative to conventional debonding methods, as the adhesion is usually separated at the bracket-adhesive interface, thereby avoiding enamel damage, independent of the adhesive used.     

Adhesive performance of precoated brackets after expiration

Objective:To evaluate adhesive performance in terms of debonding forces of precoated metal and ceramic brackets 4 years after expiration.Materials and Methods:Buccal and lingual surfaces of embedded extracted maxillary premolars were etched with 34% Tooth Conditioner Gel (Dentsply Caulk, Milford, Del), rinsed, and dried. Transbond MIP (3M Unitek, Monrovia, Calif) was applied prior to placing adhesive precoated brackets (APC II Victory stainless steel and APC Plus Clarity ceramic brackets, 3M Unitek). The preexpiration brackets had 29–35 months before, and the postexpiration brackets were 45–52 months past, their expiration dates. Sample size was 17–21 per group. Debonding forces were determined by subjecting the bonded brackets to a shear force in a universal testing machine. Debonding forces were compared using two-way ANOVA. Debonded surfaces were examined under a stereomicroscope to determine failure modes, which were compared using the chi-square test.Results:No statistically significant difference was found in debonding forces (P  =  .8581) or failure modes (P  =  .4538) between expired and unexpired brackets. Metal brackets required statistically significantly higher debonding forces than did ceramic brackets (P  =  .0001). For both expired and unexpired brackets, failure modes were mostly cohesive in the adhesive layer for ceramic brackets, and mixed between adhesive and cohesive failure in the adhesive layer for metal brackets.Conclusions:Adhesive precoated brackets did not have any reduction in enamel-adhesion properties up to 4 years after their expiration date. Extended shelf life testing for precoated dental brackets may be worth considering.     

Enamel loss following ceramic bracket debonding: A quantitative analysis in vitro

Objective:To measure enamel surface changes after ceramic bracket debonding and after cleanup.Materials and Methods:Forty extracted teeth were scanned in three dimensions using an optical scanner (baseline). Two ceramic bracket systems were placed (19 metal-reinforced polycrystalline ceramic brackets; 21 monocrystalline ceramic brackets). Seven days later, brackets were debonded and teeth scanned (post-debond). Adhesive remnants and bracket fragments were recorded. Tooth surfaces were cleaned using a finishing carbide bur and scanned again (post-cleanup). Post-debond and post-cleanup scans were aligned with the baseline, and surface changes were quantified. Results were statistically compared using t-tests and Mann-Whitney tests (α  =  .05).Results:The depth of enamel loss (mean ± standard deviation) post-debond was 21 ± 8 µm and 33 µm and post-cleanup was 28 ± 14 µm and 18 ± 8 µm (P  =  .0191); the post-debond remnant thickness was 188 ± 113 µm and 120 ± 37 µm (P  =  .2381) and post-cleanup was 16 ± 5 µm and 15 µm for polycrystalline and monocrystalline ceramic brackets, respectively. The monocrystalline ceramic brackets predominantly left all adhesive on the tooth; the polycrystalline ceramic brackets were more likely to leave bracket fragments attached.Conclusion:Both systems allowed successful removal of the brackets with minimal enamel loss. However, the polycrystalline ceramic brackets left more fragments on the tooth, which complicated cleanup efforts.     

Distortion of Metallic Orthodontic Brackets After Clinical Use and Debond by Two Methods

Abstract

The objective of this paper was to compare distortion of the wings and bases of metallic orthodontic brackets following clinical use and after debond by either of two methods, and took the form of a prospective random control trial. Five-hundred-and-seven brackets were debonded using either bracket removing pliers or a lift off debonding instrument (LODI). By a system of random allocation contralateral opposing quadrants were debonded with a 0.019 × 0.0025-inch archwire either in place or removed. After debond brackets were tested for slot closure by the fit of rectangular test wires from 0.016 × 0.022 to 0.021 × 0.025 inch size. The LODI produced few slot closures sufficient to affect the fit of all but the largest test wire. Bracket removing pliers used after removal of the archwire produced significantly greater numbers of distorted brackets in response to testing with all but the largest wire. With the 0.021 × 0.025 inch wire in place the presence or absence of the archwire at the time of debond made no difference to the number of slot closures. Ten per cent of the brackets debonded using bracket removing pliers had distorted bases, no base damage was produced by the LODI. The use of bracket removing pliers at debond caused significantly more slot closures than use of the LODI. When bracket removing pliers are used the archwire should be left in place at the time of debond since this reduces the number of distortions.     

Bracket base remnants after orthodontic debonding

Objective:To evaluate whether the debonding procedure leads to restitutio ad integrum of the enamel surface by investigating the presence of enamel within the bracket base remnants after debonding.Materials and Methods:Sixty patients who completed orthodontic treatment with fixed appliances were included. A total of 1068 brackets were microphotographed; the brackets presenting some remnants on the base (n  =  818) were selected and analyzed with ImageJ software to measure the remnant area. From this population a statistically significant sample (n  =  100) was observed under a scanning electron microscope to check for the presence of enamel within the remnants. Energy dispersive x-ray spectrometry was also performed to obtain quantitative data.Results:Statistically significant differences in the remnant percentage between arches were observed for incisor and canine brackets (P < .0001 and P  =  .022, respectively). From a morphologic analysis of the scanning electron micrographs the bracket bases were categorized in 3 groups: group A, bases presenting a thin enamel coat (83%); group B, bases showing sizable enamel fragments (7%); group C, bases with no morphologic evidence of enamel presence (10%). Calcium presence was noted on all evaluated brackets under energy dispersive x-ray spectrometry. No significant difference was observed in the Ca/Si ratio between group A (16.21%) and group B (18.77%), whereas the Ca/Si ratio in group C (5.40%) was significantly lower than that of the other groups (P < .323 and P  =  .0001, respectively).Conclusion:The objective of an atraumatic debonding is not achieved yet; in some cases the damage could be clinically relevant.     

A new flash-free orthodontic adhesive system: A first clinical and stereomicroscopic study

Objective:To analyze the clinical and laboratory properties of the recently introduced APC flash-free orthodontic adhesive.Material and Methods: After bonding of 80 brackets on human teeth (group A: APC flash-free adhesive n  =  40, group B: APC Plus adhesive n  =  40), the following measurements were recorded: time for bonding, stereomicroscopic evaluation of excess adhesive, color penetration (methylene blue, 0.5%/24 h), and Adhesive Remnant Index (ARI) score after debonding.Results:The time needed for bonding differed significantly between the two groups (A: 19.5 s/tooth vs B: 33.8 s/tooth). The adhesive excess, which was metrically measured from the bracket edge, ranged from 166.27 µm to 81.66 µm (group A) and 988.53 µm to 690.81 µm (group B). After methylene coloration in group A, 52 of 80 measurements showed discoloration on the bracket-adhesive and/or adhesive-enamel interface, while for group B, 78 of 80 were coloration positive. The ARI scores did not differ, with an average ARI score of 2.0 for group A and 2.8 for group B.Conclusion:The flash-free adhesive significantly reduced the time needed for the bonding process. The excess resin expanded 0.16 to 0.08 mm over the bracket margin. The new technology seems to facilitate a smooth and sufficient marginal surface of the adhesive, which clinically might improve reduction of plaque accumulation.     

Effects of third-order torque on frictional force of self-ligating brackets

Objective:To investigate the effects of third-order torque on frictional properties of self-ligating brackets (SLBs).Materials and Methods:Three SLBs (two passive and one active) and three archwires (0.016 × 0.022-inch nickel-titanium, and 0.017 × 0.025-inch and 0.019 × 0.025-inch stainless steel) were used. Static friction was measured by drawing archwires though bracket slots with four torque levels (0°, 10°, 20°, 30°), using a mechanical testing machine (n  =  10). A conventional stainless-steel bracket was used for comparison. Results were subjected to Kruskal-Wallis and Mann-Whitney U-tests. Contact between the bracket and wire was studied using a scanning electron microscope.Results:In most bracket-wire combinations, increasing the torque produced a significant increase in static friction. Most SLB-wire combinations at all torques produced less friction than that from the conventional bracket. Active-type SLB-wire combinations showed higher friction than that from passive-type SLB-wire combinations in most conditions. When increasing the torque, more contact between the wall of a bracket slot and the edge of a wire was observed for all bracket types.Conclusions:Increasing torque when using SLBs causes an increase in friction, since contact between the bracket slot wall and the wire edge becomes greater; the design of brackets influences static friction.     

Debris,Roughness and Friction of Stainless Steel Archwires Following Clinical Use

Objective:To investigate the degree of debris, roughness, and friction of stainless steel orthodontic archwires before and after clinical use.Materials and Methods:For eight individuals, two sets of three brackets (n  =  16) each were bonded from the first molar to the first premolar. A passive segment of 0.019- × 0.025-inch stainless steel archwire was inserted into the brackets and tied by elastomeric ligature. Debris level (via scanning electron microscopy), roughness, and frictional force were evaluated as-received and after 8 weeks of intraoral exposure. Mann-Whitney, Wilcoxon signed-rank, and Spearman correlation tests were used for statistical analysis at the .05 level of significance.Results:There were significant increases in the level of debris (P  =  .0004), roughness of orthodontic wires (P  =  .002), and friction (P  =  .0001) after intraoral exposure. Significant positive correlations (P < .05) were observed between these three variables.Conclusion:Stainless steel rectangular wires, when exposed to the intraoral environment for 8 weeks, showed a significant increase in the degree of debris and surface roughness, causing an increase in friction between the wire and bracket during the mechanics of sliding.     

Distortion of metallic orthodontic brackets after clinical use and debond by two methods.

The objective of this paper was to compare distortion of the tie wings and bases of metallic orthodontic brackets following clinical use and after debond by either of two methods, and took the form of a prospective random control trial. Five-hundred-and-seven brackets were debonded using either bracket removing pliers or a lift off debonding instrument (LODI). By a system of random allocation contralateral opposing quadrants were debonded with a 0.019 x 0.025-inch archwire either in place or removed. After debond brackets were tested for slot closure by the fit of rectangular test wires from 0.016 x 0.022 to 0.021 x 0.025 inch in size. The LODI produced few slot closures sufficient to affect the fit of all but the largest test wire. Bracket removing pliers used after removal of the archwire produced significantly greater numbers of distorted brackets in response to testing with all but the largest wire. With the 0.021 x 0.025 inch wire in place the presence or absence of the archwire at the time of debond made no difference to the number of slot closures. Ten per cent of the brackets debonded using bracket removing pliers had distorted bases, no base damage was produced by the LODI. The use of bracket removing pliers at debond caused significantly more slot closures than use of the LODI. When bracket removing pliers are used the archwire should be left in place at the time of debond since this reduces the number of distortions.     

Effect of adhesion boosters on indirect bracket bonding

Objective:To determine the influence of two adhesion boosters on shear bond strength and on the bond failure location of indirectly bonded brackets.Materials and Methods:Sixty bovine incisors were randomly divided into three groups (n  =  20), and their buccal faces were etched using 37% phosphoric acid. In group 1 (control), brackets were indirectly bonded using only Sondhi adhesive. In groups 2 and 3, the adhesion boosters Enhance Adhesion Booster and Assure Universal Bonding Resin, respectively, were applied before bonding with Sondhi. Maximum bond strength was measured with a universal testing machine, and the location of bond failure was evaluated using the Adhesive Remnant Index (ARI). One-way analysis of variance followed by the Tukey test (P < .05) was used to compare the shear bond strength among groups, and the differences in ARI scores were evaluated using the Kruskal-Wallis test (P < .05). The Pearson correlation coefficient was calculated to determine whether there was any correlation between bond strength and ARI scores.Results:The mean shear bond strength in group 3 was significantly higher (P < .01) than in the other groups. Evaluation of the locations of bond failure revealed differences (P < .05) among the three groups. There was a moderate correlation between bond strength and ARI scores within group 3 (r  =  0.5860, P < .01).Conclusion:In vitro shear bond strength was acceptable in all groups. The use of the Assure adhesion booster significantly increased both the shear bond strength of indirectly bonded brackets and the amount of adhesive that remained on the enamel after bracket debonding.     

Dimensional accuracy of ceramic self-ligating brackets and estimates of theoretical torsional play

Objective:To ascertain the dimensional accuracies of some commonly used ceramic self-ligation brackets and the amount of torsional play in various bracket–archwire combinations.Materials and Methods:Four types of 0.022-inch slot ceramic self-ligating brackets (upper right central incisor), three types of 0.018-inch ceramic self-ligating brackets (upper right central incisor), and three types of rectangular archwires (0.016 × 0.022-inch beta-titanium [TMA] (Ormco, Orange, Calif), 0.016 × 0.022-inch stainless steel [SS] (Ortho Technology, Tampa, Fla), and 0.019 × 0.025-inch SS (Ortho Technology)) were measured using a stereomicroscope to determine slot widths and wire cross-sectional dimensions. The mean acquired dimensions of the brackets and wires were applied to an equation devised by Meling to estimate torsional play angle (γ).Results:In all bracket systems, the slot tops were significantly wider than the slot bases (P < .001), yielding a divergent slot profile. Clarity-SLs (3M Unitek, Monrovia, Calif) showed the greatest divergence among the 0.022-inch brackets, and Clippy-Cs (Tomy, Futaba, Fukushima, Japan) among the 0.018-inch brackets. The Damon Clear (Ormco) bracket had the smallest dimensional error (0.542%), whereas the 0.022-inch Empower Clear (American Orthodontics, Sheboygan, Wis) bracket had the largest (3.585%).Conclusions:The largest amount of theoretical play is observed using the Empower Clear (American Orthodontics) 0.022-inch bracket combined with the 0.016 × 0.022-inch TMA wire (Ormco), whereas the least amount occurs using the 0.018 Clippy-C (Tomy) combined with 0.016 × 0.022-inch SS wire (Ortho Technology).     

Effects of adhesive flash-free brackets on debonding pain and time: A randomized split-mouth clinical trial

ObjectivesTo evaluate the effects of adhesive precoated (APC) flash-free brackets on the level of pain, amount of remnant adhesive, and removal time during the debonding procedure.Materials and MethodsThirty patients (20 female, 10 male) aged 12 to 18 years undergoing nonextraction fixed orthodontic treatment were included in this study. APC flash-free and conventional ceramic brackets were bonded with a split-mouth study design. Bracket types were randomly allocated to quadrants. During the removal of the brackets, the visual analogue scale (VAS) was used to assess the level of pain for each tooth. The adhesive remnant index (ARI) was used to determine the amount of adhesive remaining on the tooth surface. Adhesive removal times were calculated per quadrant. The data were analyzed using the Wilcoxon test for comparisons between groups.ResultsPain scores were generally higher for the conventional group than for the flash-free group. There were no differences in VAS scores across most tooth types during debonding. Overall, ARI results showed more adhesive remnants in the conventional bracket group (P < .001). Except for the right maxillary quadrant, the times required to remove the adhesive were significantly longer for the flash-free brackets than the conventional brackets (P ≤ .005).ConclusionsAlthough removal time was slightly longer for the flash-free adhesive than for the conventional adhesive, lower pain scores were generally observed for the flash-free adhesive brackets during the debonding procedure. Both time and pain differences could be considered clinically insignificant.     

Measurement and comparison of bracket transfer accuracy of five indirect bonding techniques

Objective:To measure and compare bracket transfer accuracy of five indirect bonding (IDB) techniques.Materials and Methods:Five IDB techniques were studied: double polyvinyl siloxane (double-PVS), double vacuum-form (double-VF), polyvinyl siloxane vacuum-form (PVS-VF), polyvinyl siloxane putty (PVS-putty), and single vacuum-form (single-VF). Brackets were bonded on 25 identical stone working models. IDB trays were fabricated over working models (n  =  5 per technique) to transfer brackets to another 25 identical stone patient models. The mesiodistal (M-D), occlusogingival (O-G), and faciolingual (F-L) positions of each bracket were measured on the working and patient models using digital photography (M-D, O-G) and calipers (F-L). Paired t-tests were used to compare bracket positions between working and patient models, and analysis of variance was used to compare bracket transfer accuracy among the five techniques.Results:Between the working and patient models, double-VF had the most teeth with significant differences (n  =  6) and PVS-VF the fewest (n  =  1; P < .05). With one exception, all significant differences were ≤0.26 mm and most (65%) were ≤0.13 mm. When the techniques were compared, bracket transfer accuracy was similar for double-PVS, PVS-putty, and PVS-VF, whereas double-VF and single-VF showed significantly less accuracy in the O-G direction.Conclusions:Although overall differences in bracket position were relatively small, silicone-based trays had consistently high accuracy in transferring brackets, whereas methods that exclusively used vacuum-formed trays were less consistent.     

Orthodontic bracket bonding without previous adhesive priming: A meta-regression analysis

Objective:To determine the consensus among studies that adhesive resin application improves the bond strength of orthodontic brackets and the association of methodological variables on the influence of bond strength outcome.Materials and Methods:In vitro studies were selected to answer whether adhesive resin application increases the immediate shear bond strength of metal orthodontic brackets bonded with a photo-cured orthodontic adhesive. Studies included were those comparing a group having adhesive resin to a group without adhesive resin with the primary outcome measurement shear bond strength in MPa. A systematic electronic search was performed in PubMed and Scopus databases.Results:Nine studies were included in the analysis. Based on the pooled data and due to a high heterogeneity among studies (I²  =  93.3), a meta-regression analysis was conducted. The analysis demonstrated that five experimental conditions explained 86.1% of heterogeneity and four of them had significantly affected in vitro shear bond testing. The shear bond strength of metal brackets was not significantly affected when bonded with adhesive resin, when compared to those without adhesive resin.Conclusions:The adhesive resin application can be set aside during metal bracket bonding to enamel regardless of the type of orthodontic adhesive used.     

Comparison of bond strength between simple foil mesh and laser-structured base retention brackets.

The aims of the current study were to evaluate the bond strength of a new metallic orthodontic bracket with a laser structured base (Discovery, Dentaurum, Ispringen, Germany), and its effects on the site of bond failure and on the behavior of the enamel after debonding. One hundred and twenty recently extracted human premolars were bonded with 1 of 2 types of mechanical interlock base metal brackets: a standard system with a simple foil mesh pad (Minitrim, Dentaurum) and the Discovery bracket. A resin-based, chemically activated bonding system, No-mix (Dentaurum), was used as the adhesive system in this trial. The teeth were immersed in normal saline solution at 37 degrees C for 7 days before debonding and were randomly assigned to different subgroups. A testing machine was used to evaluate tensile and fatigue bond strengths for both brackets. After debonding, the amount of residual adhesive on the bracket and enamel detachment were assessed according to the adhesive remnant index (ARI) and the enamel detachment index (EDI) with a scanning electron microscope and an energy dispersive X-ray spectrometer. The scores obtained from the ARI and the EDI showed that the laser structured base brackets had a significantly higher bond strength (mean +/- SD: 17.1 +/- 0.7 MPa) that was 2 times higher than that observed with the simple foil mesh brackets (mean +/- SD: 8.7 +/- 1.4 MPa) (P <.001). Bond failure with the laser structured base was at the enamel-adhesive interface with an ARI score of 3 in 80% of the teeth, and bond failure with the simple foil mesh base was at the bracket-adhesive interface with an ARI score of 0 in 75% of the teeth. A small area, with less than 10% of the enamel damaged (1 on the EDI) and 1.5 microm in thickness, was observed for both brackets. The laser structured base bracket's bond strength was double that of the simple foil mesh bracket but was equally safe and did not induce significant enamel detachment.     

Porcelain Surface Alterations and Refinishing After Use of Two Orthodontic Bonding Methods

Objective:To compare porcelain surfaces at debonding after use of two surface preparation methods and to evaluate a method for restoring the surface.Materials and Methods:Lava Ceram feldspathic porcelain discs (n  =  40) underwent one of two surface treatments prior to bonding orthodontic brackets. Half the discs had sandblasting, hydrofluoric acid, and silane (SB + HF + S), and the other half, phosphoric acid and silane (PA + S). Brackets were debonded using bracket removing pliers, and resin was removed with a 12-fluted carbide bur. The surface was refinished using a porcelain polishing kit, followed by diamond polishing paste. Measurements for surface roughness (Ra), gloss, and color were made before bonding (baseline), after debonding, and after each step of refinishing. Surfaces were also examined by scanning electron microscopy (SEM). Data was analyzed with 2-way ANOVA followed by Tukey HSD tests (α  =  0.05).Results:The SB + HF + S bonding method increased Ra (0.160 to 1.121 µm), decreased gloss (41.3 to 3.7) and altered color (ΔE  =  4.37; P < .001). The PA + S method increased Ra (0.173 to 0.341 µm; P < .001), but the increase in Ra was significantly less than that caused by the SB + HF + S bonding method (P < . 001). The PA + S method caused insignificant changes in gloss (41.7 to 38.0) and color (ΔE  =  0.50). The measurements and SEM observations showed that changes were fully restored to baseline with refinishing.Conclusions:The PA + S method caused significantly less damage to porcelain than the SB + HF + S method. The refinishing protocol fully restored the porcelain surfaces.     

A novel biomimetic orthodontic bonding agent helps prevent white spot lesions adjacent to brackets

Objective:To compare changes in enamel microhardness adjacent to orthodontic brackets after using bonding agents containing various compositions of bioactive glass compared to a traditional resin adhesive following a simulated caries challenge.Materials and Methods:Extracted human third molars (n  =  10 per group) had orthodontic brackets bonded using one of four novel bioactive glass (BAG)-containing orthodontic bonding agents (BAG-Bonds) or commercially available Transbond-XT. The four new adhesives contained BAG in varying percentages incorporated into a traditional resin monomer mixture. Teeth were cycled through low-pH demineralizing and physiologic-pH remineralizing solutions once each day over 14 days. Microhardness was measured on longitudinal sections of the teeth 100, 200, and 300 µm from the bracket edge and beneath the brackets, at depths of 25 to 200 µm from the enamel surface. Normalized hardness values were compared using three-way analysis of variance.Results:Significantly less reduction in enamel microhardness was found with the experimental adhesives at depths of 25 and 50 µm at all distances from the bracket edge. In all groups, there were no significant changes in enamel microhardness past 125-µm depth. Results varied with the different BAG-Bonds, with 81BAG-Bond showing the smallest decrease in enamel microhardness.Conclusions:The BAG-Bonds tested in this study showed a reduction in the amount of superficial enamel softening surrounding orthodontic brackets compared to a traditional bonding agent. The results indicate that clinically, BAG-Bonds may aid in maintaining enamel surface hardness, therefore helping prevent white spot lesions adjacent to orthodontic brackets.     

A prospective randomized split-mouth study on pain experience during chairside archwire manipulation in self-ligating and conventional brackets

Objective:To investigate patient discomfort during archwire engagement and disengagement in patients treated with self-ligating and conventional brackets using a split-mouth design.Materials and Methods:Eighteen consecutive patients (15 female, 3 male; age: 22.2 ± 6.4 years) who requested treatment with fixed orthodontic appliances were randomly assigned for bonding with SmartClip self-ligating brackets on one side of the dentition and conventional standard edgewise brackets on the other. During the course of treatment, patients rated the discomfort experienced during every archwire engagement and disengagement using a numeric rating scale. Results were evaluated for round and rectangular nickel titanium and rectangular stainless steel, titanium molybdenum, and Elgiloy archwires. Patients also rated their overall experience retrospectively for both bracket systems.Results:Regardless of archwire type, disengagement was rated as being significantly more painful on the SmartClip side (P  =  .027). For rigid, rectangular archwires, engagement and disengagement were rated as being significantly more painful on the SmartClip side (P  =  .031; P  =  .004). Retrospective ratings favored conventional brackets beyond ratings recorded during treatment.Conclusion:Engagement and disengagement of rigid rectangular archwires caused more pain with SmartClip self-ligating brackets than with conventional ones. Careful archwire manipulation and patience during full alignment are essential for limiting chairside pain. Low pain levels will help ensure treatment satisfaction and compliance.     

Influence of bracket-slot design on the forces released by superelastic nickel-titanium alignment wires in different deflection configurations

Objective:To evaluate how different bracket-slot design characteristics affect the forces released by superelastic nickel-titanium (NiTi) alignment wires at different amounts of wire deflection.Materials and Methods:A three-bracket bending and a classic-three point bending testing apparatus were used to investigate the load-deflection properties of one superelastic 0.014-inch NiTi alignment wire in different experimental conditions. The selected NiTi archwire was tested in association with three bracket systems: (1) conventional twin brackets with a 0.018-inch slot, (2) a self-ligating bracket with a 0.018-inch slot, and (3) a self-ligating bracket with a 0.022-inch slot. Wire specimens were deflected at 2 mm and 4 mm.Results:Use of a 0.018-inch slot bracket system, in comparison with use of a 0.022-inch system, increases the force exerted by the superelastic NiTi wires at a 2-mm deflection. Use of a self-ligating bracket system increases the force released by NiTi wires in comparison with the conventional ligated bracket system. NiTi wires deflected to a different maximum deflection (2 mm and 4 mm) release different forces at the same unloading data point (1.5 mm).Conclusion:Bracket design, type of experimental test, and amount of wire deflection significantly affected the amount of forces released by superelastic NiTi wires (P < .05). This phenomenon offers clinicians the possibility to manipulate the wire''s load during alignment.