Types Of Brackets Research Articles

Comparative in vitro analysis of the sliding resistance of a modern 3D-printed polymer bracket in combination with different archwire types.

ObjectivesTo analyse the sliding resistance of a modern 3D-printed polymer bracket combined with different archwire types and to compare the results with conventionally used polymeric, ceramic and metal brackets. It was of further interest which bracket-archwire combination could be best qualified for clinical use.Materials and methodsThe sliding behaviour was tested using an orthodontic measurement and simulation system (OMSS) for the use of two bracket types of the polymer, ceramic and metal group in combination with a 0.016 inch × 0.022 inch and 0.017 inch × 0.025 inch archwire of nickel-titanium (NiTi), titanium-molybdenum alloy (TMA) and stainless steel. Six bracket types were combined with six different archwire types and compared to each other.ResultsThe sliding resistance showed significant differences between various the bracket-archwire complexes. The combination of 3D-printed polymer brackets with both steel archwire cross-sections showed the least values of sliding resistance (average 23–29%), while the combination of ceramic brackets with TMA archwires presented the highest (average 47%).ConclusionsThe present study could show that modern 3D-printed bracket materials can have similar or even better mechanical properties than conventional ones regarding sliding resistance. Although the combination of bracket and archwire material is decisive for low sliding resistance values, the selection of the bracket material seems to have a greater influence than the selection of the archwire material or its cross section.Clinical relevanceIt might be possible in future to combine aesthetic and biomechanical requirements for aesthetic brackets by using 3D-printing technology.

Self-ligating brackets exhibit accumulation of high levels of periodontopathogens in gingival crevicular fluid

Different types of brackets seem to influence the disruption of the oral microbial environment. Therefore, the aim of this study was to evaluate the influence of self-ligating brackets on the gingival crevicular fluid levels of the putative periodontal pathogens Aggregatibacter actinomycetemcomitans sorotype a (Aaa), Tannerella forsythia, Fusobacterium nucleatum, and Porphyromonas gingivalis. Sixty samples of crevicular fluid of twenty patients (11 boys and 9 girls) were analysed at baseline (T0) and after 30 (T1) and 60 (T2) days of bonding of the self-ligating (In-Ovation®R, Dentsply, GAC or SmartClip™, 3M Unitek, Monrovia, CA, USA) and of one conventional bracket (Gemini™, 3M Unitek, Monrovia, CA, USA) used with elastomeric ligatures. Total DNA from samples was extracted using CTAB-DNA precipitation method and Real-time PCR was performed to analyse bacterial level. Non-parametric Friedman and Wilcoxon tests were used for data analysis (p value of < 0.05). F. nucleatum presented a different level among the different brackets at T1 (p = 0.025), the highest level in the Gemini™ bracket when compared to the SmartClip™ bracket (p = 0.043). P. ginigvalis levels increased in the In-Ovation®R (p = 0.028) at T1. The subgingival levels of bacterial species associated with periodontal disease P. ginigvalis increased in the self-ligating brackets In-Ovation®R.Clinical Relevance: Some kinds of brackets could provide more retentive sites than others, and it seems to modulate the subgingival microbiota, since, in this study, we could observe the increase of the species associated with periodontal disease. Preventive protocols should be adopted in the use of self-ligating brackets.

Frictional Resistance of Non Coated and Epoxy Coated Superelastic NiTi Wires used for Aligning in Three Types of Brackets

Introduction: Coated archwires are preferred in combination with aesthetic orthodontic brackets by orthodontists over non metallic aesthetic archwires. Studies evaluating the frictional properties of epoxy coated round superelastic Nickel Titanium (NiTi) archwires are limited to stainless steel brackets. Aim: To evaluate and compare the frictional resistance of an epoxy coated 0.016" superelastic NiTi archwire in stainless steel, composite and ceramic brackets and to compare it with the frictional resistance generated by non coated 0.016" superelastic NiTi archwire in same brackets. Materials and Methods: An in-vitro experimental study was conducted in the Department of Orthodontics at SRM Dental College from January to February 2020. Frictional resistance of 30 epoxy coated aesthetic 0.016" upper superelastic NiTi wires (G4™ Nickel Titanium, 0.016, Upper Trueform™ I, ToothColored) and 30 conventional 0.016" upper superelastic NiTi wires (G4™ Nickel Titanium, 0.016, Upper Trueform™) from G&amp;H® orthodontics while sliding across three different types of brackets were evaluated. Twenty stainless-steel (Gemini® 3M unitek, Monrovia, California), 20 composite (FLI® RMO, Denver, Colo.), and 20 gemini clear ceramic (Gemini clear ® 3M unitek, Monrovia, California) 0.022x0.028" Slot Roth prescription maxillary first premolar brackets were used. The brackets and archwires were divided into six groups of different bracket and archwire combination with 10 samples in each. An Instron testing machine with a 10 N tension was used to measure the frictional resistance. The obtained values were analysed using One-way ANOVA and followed by Post Hoc Tukey HSD for multiple comparison. Results: Coated wires generated significantly high friction in ceramic brackets (136.90±3.79 gms) followed by composite brackets (125.66±3.44 gms) and stainless steel brackets (92.53±8.70 gms). Non non coated wires generated significantly high friction with ceramic brackets (89.60±2.90 gms) whereas the friction generated in composite (70.87±5.79 gms) and stainless steel brackets (67.70±2.80 gms) was not significantly different. Conclusion: Epoxy coating increased the frictional resistance generated by the 0.016 superelastic NiTi archwires irrespective of bracket materials. The coated wires generated less friction in composite brackets compared to ceramic brackets. Further clinical trial are recommended to evaluate the aligning efficacy of these archwires in aesthetic brackets.

Bond strength of different orthodontic brackets produced with different materials and fabrication methods

Objective: The aim of this study was to evaluate the effects of material and processing methods on the bondstrength of orthodontic brackets. Material and Methods: Five types of brackets were tested: Conventionalmetallic (CM), metallic sandblasted (SB), ceramic (C), polycarbonate (PC), and metallic fabricated by meltinginjection molding (MIM). Shear bond strength (SBS) was conducted to check bond strength of the bracketsbonded to bovine teeth (n=10/group), and tensile bond strength (TBS) (20 brackets/group) to check bracketretention to bonding material (n=20/group). Both, SBS and TBS were conducted with 1mm/min crossheadspeed in a universal testing machine. Bond strength was calculated in Megapascal (MPa) based on force (N) andbracket area (mm2). Data normality was verified, and One-way ANOVA was the statistical test with Tukey posthoc(a=0.05). Results: SB and MIM presented higher SBS compared to C, PC, and CM (p&lt;0.05). SB and MIMalso presented significantly higher TBS compared to CM and PC (p&lt;0.05). However, MIM was not different ofC for TBS. Conclusion: The type of material and method of fabrication are determinant factors that affect bondstrength of orthodontic brackets and melting injection molding (MIM) is a remarkable technology to improvebrackets retention during the orthodontic treatment. KEYWORDSBond strength; Orthodontic brackets; Melting injection molding.

Comparative evaluation of transverse dental arch width changes with conventional and self-ligating brackets

Aim: This study aims at comparing the transverse width changes during leveling and aligning phase with conventional and self-ligating brackets. Materials and Methods: The study consisted of twenty samples. The sample was split into two groups. Group 1 consisted of ten samples treated with conventional brackets and ten samples treated with self-ligating brackets. Pretreatment and leveling aligning cast were used for the study. Measurement of transverse dimension was taken at two different regions, premolar and molar. Reference points were chosen according to the Pont's model analysis. In the premolar region, measurements were made from the distal pit of the first premolar on either side, and in the molar region, measurements were made from the mesial pit on either side. The overall values are compiled and compared among both the bracket groups. Results: The results of the study showed that there were changes in the interpremolar and intermolar arch width during leveling and aligning phase in both the bracket types. Conclusion: Since the arch width changes can affect the stability in the posttreatment phase, an orderly use of custom-made archwires from the very beginning is advised. The amount of arch width changes that occur with the treatment is irrespective of the bracket type, provided that other factors are maintained to be constant. Both conventional metal-ligated brackets and dual-activation self-ligating brackets provide an equal amount of changes in the dental arch transverse dimensions.

The effect of various nanoparticle coating on the frictional resistance at orthodontic wire and bracket interface: A systematic review.

This systematic review was aimed to test the null hypothesis that coating of orthodontic wires with nanoparticles does not affect the frictional properties at bracket--wire interface. Electronic database searches were performed up to September 2020. In vitro studies were considered for reviewing process. Study selection, data extraction, risk of bias assessment was performed during reviewing process. Only qualitative analyses of included literature were done due to the presence of heterogeneity among the studies. Out of 1,068 retrieved records, nine studies satisfied the inclusion criteria and included in this review. Studies were assessed at low risk to high risk of bias according to certain parameters. Wide variety of nanoparticles were used for surface coating of orthodontic wires of variable sizes, shapes, and materials like stainless steel, NiTi, and TMA and placed into the slots of different types of orthodontic brackets to evaluate the alteration in frictional and other mechanical properties. Most of the studies clearly indicate that coating with nanoparticles decreases the friction between wire and bracket interface under specified in vitro conditions. Furthermore, among the nine included studies, only two considered evaluation of effect of coated brackets on frictional and other mechanical properties and results were heterogeneous. The null hypothesis is rejected and it is concluded that the wires coated with nanoparticles might offer a novel opportunity to substantially reduce frictional resistance at bracket--wire interface during tooth movement. Further studies are necessary to strengthen the evidence regarding effect of coated brackets on frictional properties.

Comparison of Shear Bond Strength of a Newly Introduced Primer with Conventional Primer Using Two Types of Brackets Bonded to Different Surfaces: An In Vitro Study

Background Increasing prevalence of adult orthodontics necessitates improvement in bonding techniques to different intraoral surfaces enamel composite amalgam porcelain. Research focusing on newer materials minimizing bond failures is important as replacing loose brackets is inefficient time-consuming and costly.Objective To compare the shear bond strength SBS and adhesive remnants achieved with the new Assure Plus AP primer versus conventional Transbond XT TXT primer for bonding metalceramic brackets to three different surfaces tooth enamel composite and porcelain-fused-to-metal PFM ceramic.Methods This in vitro study included 40 samples each of extracted teeth Group-1 composite restorations Group-2 and PFM crowns Group-3 mounted on acrylic blocks onto which metal Category-M or ceramic Category-C brackets were bonded using TXT Subgroup-A or AP primer Subgroup-B 10 samples in each class. Their SBS and Adhesive Remnant Index ARI were compared between and within the groups using ANOVA Tukeyrsquos post hoc analysis and Weibull analysis. The level of significance was set at p lt0.05.Results The two primers showed no significant differences in mean SBS within Groups-1 and 2 and in mean ARI within any group p gt0.05. Group-3 showed higher mean SBS with AP primer than with TXT primer BCgtBMgtACgtAM p lt0.001. Failure probability was also lower with AP than with TXT primer.Conclusion AP primer showed significantly greater SBS than TXT primer when used for bonding brackets to PFM crowns. AP primer also showed lower failure probability than TXT primer on all three surfaces tooth enamel composite PFM ceramic.

Influence of orthodontic brackets and permanent retainers on the diagnostic image quality of MRI scans: A preliminary study.

Orthodontic treatment with fixed mechanotherapy using appliances and permanent retainers bonded after treatment is a routine procedure performed in clinical dentistry. Patients with braces or retainers sometimes need to undergo magnetic resonance imaging (MRI) for various reasons. Radiologists do not know the exact impact of the materials used in orthodontics on the diagnostic image quality of MRI scans. The aim of the study was to evaluate the influence of different types of orthodontic brackets and permanent retainers on the diagnostic image quality of MRI scans. Twenty patients with bonded brackets (stainless steel buccal/labial, stainless steel lingual, ceramic self-ligating with metal slots, ceramic, and polycarbonate) and 18 patients with bonded fixed retainers (titanium, fiber-reinforced composite, multi-stranded stainless steel, and different combinations of permanent retainers) participated in the study. The same adhesive was used for bonding. Cranial MRI scans of 6 regions were acquired for each subject, using a 1.5T MAGNETOM machine. Six radiologists evaluated the images and provided scores based on the modified receiver operating characteristic (ROC) analysis of distortion. The paired Wilcoxon signed-rank test was used to assess differences between the materials and the anatomic sites with regard to the distortion rating scale. Cohen's kappa coefficient (κ) was applied to establish the interrater reliability. A statistically significant difference was found between stainless steel brackets (both buccal/ labial and lingual) and all other experimental materials in terms of mean distortion scores (p = 0.020 or p = 0.024). The interrater reliability proved to be high. Stainless steel buccal/labial and lingual brackets caused maximum distortion of the images, which became non-diagnostic; hence, such brackets should be removed before MRI. Ceramic and polycarbonate brackets as well as fiber-reinforced composite retainers did not distort the images; thus, they need not be removed. Ceramic self-ligating brackets with metal slots, titanium retainers, multi-stranded stainless steel retainers, and combinations of fixed retainers caused minimal distortion; however, the images were still diagnostic. Hence, patients using these materials may not need to have them removed before MRI.

Microbial colonisation associated with conventional and self-ligating brackets: a systematic review.

Background:Decalcification and gingivitis caused by plaque accumulation around brackets are common iatrogenic effects of fixed appliances. The influence of conventional versus self-ligating bracket design on microbial colonisation is unknown.Objective:To assess the levels of microbial colonisation associated with conventional and self-ligating brackets.Search sources:Three databases were searched for publications from 2009 to 2021.Data selection:Randomised controlled trials comparing levels of microbial colonisation before and during treatment with conventional and self-ligating brackets were assessed independently and in duplicate.Data extraction:Data were extracted independently by two authors from the studies that fulfilled the inclusion criteria. Risk of bias assessments were made using the revised Cochrane risk of bias tool for randomized trials. The quality of the included studies was assessed using the Critical Appraisal Skills Programme Checklist.Results:A total of 11 randomised controlled trials were included in this systematic review. Six of the studies were found to be at low risk of bias and five presented with some concerns. The studies were considered moderate to high quality. Five trials reported no statistically significant difference in microbial colonisation between bracket types. The remaining studies showed mixed results, with some reporting increased colonisation of conventional brackets and others increased colonisation of self-ligating brackets. The heterogeneity of study methods and outcomes precluded meta-analysis.Conclusion:Of the 11 studies included in this systematic review, five found no differences in colonisation between conventional and self-ligating brackets. The remaining studies showed mixed results. The evidence is inconclusive regarding the association between bracket design and levels of microbial colonisation.

Comprehensive evaluation of factors that induce gingival enlargement during orthodontic treatment: A cross-sectional comparative study.

Gingival enlargement (GE) is one of the most common soft tissue problems encountered during fixed orthodontic treatment. Aims: This study aimed to evaluate the factors affecting GE in adolescents and young adults, compared with their normal peers. This is a cross-sectional comparative study. The sample consisted of 329 subjects (ages 10-30 years) of both genders, which was divided into four main groups: The control group (G0) with no orthodontic treatment; subjects who underwent orthodontic treatment were divided according to treatment duration into G1 (4-12 months), G2 (13-24 months), and G3 (>24 months). The clinical examinations included the level of debris, calculus (simplified oral hygiene), and GE indices. Regression analyses were used to assess the GE association in all the studied groups. The mean GE score increased significantly with increased treatment duration (0.42 ± 0.29 for G0 and 1.03 ± 0.52 for G3). GE scores of the lower arch were significantly higher in the anterior segment than in the posterior segment among all treatment groups. Regression analysis revealed that gender, age, oral hygiene, and treatment duration had a significant effect on GE (P < 0.05), while angle classification, overjet, overbite, treatment stage, bracket type, and therapeutic extraction did not show significant associations (P > 0.05). Gender, age, oral hygiene, and treatment duration were the most important risk factors for GE during fixed orthodontic treatment.

The Impact of Different Types of Orthodontic Appliances and Its Location in Producing CT Scan Artefacts

Fixed orthodontic appliances can produce metal artefacts in CT images which may degrade the diagnostic image quality. The study aimed to evaluate the artefacts based on the types and location of the metallic and non-metallic orthodontic brackets. This is an in-vitro cross-sectional study. Four different types of orthodontic brackets (stainless steel, titanium, monocrystalline, and polycrystalline ceramic bracket) were bonded consecutively in four different locations of the cadaveric skull. All scans were performed by a single operator using the same CT machine followed by a standard scanning protocol. Artefact intensity for all data sets was quantified by calculating the standard deviation (SD) of the grey values within the dataset by following a standard method. The One-way ANOVA Bonferroni test was used for the data analysis. The mean artefact score of the stainless steel bracket was significantly (p &lt; 0.001) high in comparison with other types of the orthodontic brackets. Besides, the mean artefact score was significantly (p=0.002) low when orthodontic brackets were placed unilaterally. Stainless steel brackets produced a significant amount of noise in CT images which can degrade the diagnostic image quality. Thus, the polycrystalline ceramic bracket can be a better alternative of stainless steel brackets for patient need frequent CT scan.

Evaluation of maxillary alveolar bone changes following canine retraction with different types of orthodontic brackets (cone beam study)

Background: The alveolar bone is traditionally and practically considered the anatomical limitation of orthodontic tooth movement. Canine retraction is important step in cases with incisor crowding where extraction provides space for incisor alignment without the need to procline them. Materials and methods: This randomized clinical trial was carried on twenty patients candidates for extraction camouflagic treatment. CBCT was done to all patients and buccal bone thickness was evaluated. The patients was devided into 2 groups. The treatment of group (A) was done using self-ligating brackets and group (B) treatment was done using conventional brackets. Canine retraction was done using sliding mechanics After canine retraction completion CBCT was done again and buccal bone thickness was evaluated again. Results: The results show that there was statistically significant increase in canine labial bone thickness at L1, L2 and L3 in group (A) and group (B) after canine retraction. The results show that there was statistically insignificant difference in percentage of change of canine labial bone thickness at L1, L2 and L3 between group (A) and (B). Conclusion: There was a statistically significant increase in labial bone thickness between (Pre) and (Post) groups with both conventional and SL brackets.

Evaluation of maxillary alveolar bone changes following canine retraction with different types of orthodontic brackets (cone beam study)

Background: The alveolar bone is traditionally and practically considered the anatomical limitation of orthodontic tooth movement. Canine retraction is important step in cases with incisor crowding where extraction provides space for incisor alignment without the need to procline them. Materials and methods: This randomized clinical trial was carried on twenty patients candidates for extraction camouflagic treatment. CBCT was done to all patients and buccal bone thickness was evaluated. The patients was devided into 2 groups. The treatment of group (A) was done using self-ligating brackets and group (B) treatment was done using conventional brackets. Canine retraction was done using sliding mechanics After canine retraction completion CBCT was done again and buccal bone thickness was evaluated again. Results: The results show that there was statistically significant increase in canine labial bone thickness at L1, L2 and L3 in group (A) and group (B) after canine retraction. The results show that there was statistically insignificant difference in percentage of change of canine labial bone thickness at L1, L2 and L3 between group (A) and (B). Conclusion: There was a statistically significant increase in labial bone thickness between (Pre) and (Post) groups with both conventional and SL brackets.

Rate of Canine Retraction and Anchorage Loss – In Smart Clip versus Conventional Brackets (An in-vivo study)

Background: To analyse the rate of maxillary canine retraction and anchorage loss in Smart Clip Self Ligating (SCSL) and Conventional (CV) brackets. Materials and Methods: Forty four subjects were selected for the study requiring sectional maxillary canine retraction in first premolar extraction space during orthodontic treatment. The self ligating bracket (Smart Clip, 3M Unitek) on maxillary canine was compared to CV bracket (APC Victory series) on the contralateral side in a random split-mouth study design. Sectional canine retraction was done with a NiTi coil spring (150 gms force, 9 mm) on 0.016 í— 0.022" slot stainless steel wire. Results: The mean rate of distal movement of maxillary canine for the conventional (CV) bracket per 28 days was 1.048 mm and 1.027 mm for smart clip self ligating bracket (SCSL). Anchorage loss in molar was 0.586 mm and 0.652 mm for CV and SCSL bracket respectively. Conclusion: The rate of canine retraction for conventional bracket was faster than self ligating bracket, but not statistically significant (p&gt;0.05). Comparatively, no major difference was found in terms of molar anchor loss between both bracket types. Therefore, this study indicates that conventional brackets are equally efficient as compared to self ligating brackets for segmental canine retraction mechanics.

Qualitative and Quantitative Evaluation of Different Types of Orthodontic Brackets and Archwires by Optical Microscopy and X-ray Fluorescence Spectroscopy

The wear behaviour and chemical composition of orthodontic components influence the mechanical characteristics of a fixed orthodontic treatment. The purpose of this paper is to evaluate the surface alterations of different types of brackets (aesthetic, metallic, and conventional self-ligating) and archwires (superelastic and thermal) subjected to wear tests through optical microscopy and, subsequently, to identify the chemical elements of accessories by X-ray fluorescence. The cycles (5000 for each bracket and 10,000 for each wire) of the tribological test were carried out in dry conditions inside a machine that allows alternating sliding. The results of the study highlighted different wear behaviours even within the same type of brackets and archwires. The monocrystalline sapphire brackets maintain their aesthetic properties despite traces of wear inside the slots and contain minimal amounts of nickel. Superelastic NiTi archwires have a better overall rating than thermal wires, as they do not show significant surface wear alterations.

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.

Friction evaluation of an elastic chain positioned under or over the wire in self-ligating brackets

Objectives: This study aimed to evaluate the frictional resistance produced by active and passive self-ligating brackets on stainless steel archwires in the absence or presence of elastomeric chains under or over the wire. Materials and Methods: Four types of self-ligating brackets were used: Two active and two passive. For each commercial brand, five brackets were bonded to an acrylic plate and the frictional resistance was evaluated with 0.018” and 0.019” × 0.025” stainless steel wires in three situations: Without elastomeric chain, with elastomeric chain placed under and over the wire. Results: The bracket type, cross-section of the wire, and type of ligation had significant interactions with each other; the frictional resistance was significantly lower with the use of passive self-ligated brackets, while no difference was found when a 0.018” wire was tested. Moreover, the frictional resistance in the absence of an elastomeric chain, or when the chain was under the wire, was significantly lower in comparison with the values obtained when the chain was placed on the wire. Conclusion: Frictional resistance of passive and active self-ligated brackets is influenced by the ligation methods and the cross-sectioning of archwires.

Safe Debonding of Fixed Appliances: A Comparison of Traditional Techniques and LODI Devices on Different Bracket Types in Terms of Enamel Cracks, Site of Bond Failure, and Bracket Reusability

The objective of this study was to compare the effects of the debonding of three different bracket types by means of three popular debonding methods. A total of 180 human third molars was divided into six groups, consisting of 20 teeth each. Three bracket types were bonded to the enamel (metal brackets with an integral base and a foil mesh base, and ceramic brackets) and three methods of bracket debonding were employed (bracket removal pliers, Weingart pliers, and Lift-Off Debonding Instrument). The samples were examined with scanning electron microscopy to assess the number of enamel cracks, measure the area of adhesive remaining on the enamel, and calculate the adhesive remnant index (ARI). There were no statistically significant differences between the groups in terms of the number of enamel cracks after bracket debonding. The amount of adhesive remaining on the teeth after the brackets were removed was significantly different between the groups. LODI and Weingart pliers are considered to be the safest methods of debonding brackets with an integral base, while LODI is the best tool for brackets with foil mesh. Bracket removal pliers are considered to be the preferred method for ceramic bracket debonding.

Sliding behaviour and surface quality after static air polishing of conventional and modern bracket materials : In vitro analysis.

As part of orthodontic treatment, air polishing is routinely used for professional tooth cleaning. Thus, we investigated the effects of static powder polishing on sliding behaviour and surface quality of three different bracket materials (polymer, ceramic, metal), including a3D-printed bracket. Two bracket types of each material group were polished with an air-polishing device using sodium bicarbonate. Exposure times were set at 10, 20, and 60 s; the application distance was 5 mm. The force loss due to sliding resistance was tested with an orthodontic measurement and simulation system (OMSS) using a0.016 inch × 0.022 inch stainless steel archwire. Untreated brackets served as control. Polishing effects and slot precision were evaluated using an optical digital and scanning electron microscope. Sliding behaviour and slot precision differed significantly between and within the groups. Prior to polishing, polymer brackets showed the least force loss, ceramic brackets the highest. With progressive polishing time, the resistance increased significantly with titanium brackets (26 to 37%) and decreased significantly with steel brackets (36 to 25%). Polymer brackets showed the smallest changes in force loss with respect to polishing duration. Slot precision showed the largest differences between material groups and was primarily manufacturer-dependent with hardly any changes due to the polishing time. Powder polishing can positively or negatively affect the sliding properties of the bracket-archwire complex but is more dependent on the bracket-archwire material combination (i.e., manufacture-dependent slot precision). For titanium brackets, resistance only increased after 60 s of polishing. For ceramic brackets, effective reduction was observed after 10 s of polishing. Polymer brackets, including the 3D-printed brackets, showed better sliding properties than ceramic or metal brackets even after polishing for 60 s. Removal of plaque and dental calculus should lead to anoticeable improvement of the sliding properties and outweighs structural defects that may develop.

In vitro study of bond strength at the resin/brackets interface in first premolars using orthodontics resins and restorative resins

The shear bon strength (SBS) to brackets to the teeth, is necessary strength to resist orthodontic movements, mastication forces induced by food and other forces. The retention mechanism of the bracket base, the preparation of dental and the adhesive material affecting the adhesion between the metal brackets and tooth enamel. Therefore, the purpose of this study is to investigate different systems adhesion; Z100 (3M Unitek, USA), Transbond XT (3M Unitek, USA) and Trulock (RMO, USA) on the shear bond strength of brackets to the enamel. 135 first human premolars, mounted on an acrylic base, were divided into 3 groups of 45 pieces each. They are prepared following the same protocol and a same type of metal brackets bonded, light activated for 40 s, and stored. SBS was performed in an Instron at crosshead speed of 2.0 mm/min. Data were submitted to the Student t test. The Adhesive Remaining Index (ARI) was evaluated. The is no statistical difference between 3 groups. The ARI showed a predominance of scores 2 and 3 for all groups. It is possible conclude that Z100 restoration resin can be used to the adhesion of the orthodontic brackets.