Orthodontic Brackets Research Articles

Effects of Adding Tricalcium Silicate Nanoparticles to the Universal G2 Bond Adhesive as Self-Etch Mode on the Shear Bond Strength to the Orthodontic Bracket.

This study investigated the effects of adding tricalcium silicate nanoparticles (TCSNp) to the universal G2 bond adhesive (G2BU) in self-etch (SE) mode on shear bond strength (SBS) to orthodontic brackets, cytotoxicity, and degree of conversion (DC). A total of 176 human teeth were divided into four groups based on TCSNp concentration in G2BU adhesive: 0% (control), 1%, 3%, and 5%. The G2BU adhesive consists of a hydrophilic primer (P) and a hydrophobic bonding agent (2B). TCSNp were added to the 2B component by mixing 0.1, 0.3, and 0.5 g of TCSNp with 9.9, 9.7, and 9.5 g of 2B, respectively. SBS was assessed after 24 h of water storage and 5000 thermocycles using a universal testing machine. Cytotoxicity was evaluated using the MTT assay on rat embryo fibroblast cells, and DC was measured using fourier-transform infrared spectroscopy. Statistical analysis included one-way ANOVA and Tukey's post-hoc test, with significance set at p < 0.05. After 24 h, mean SBS values were 15.58 MPa (control), 13.66 MPa (1% TCSNp), 15.99 MPa (3% TCSNp), and 12.04 MPa (5% TCSNp). After 5000 thermocycles, SBS values decreased to 12.91 MPa (control), 12.42 MPa (1% TCSNp), 11.11 MPa (3% TCSNp), and 10.21 MPa (5% TCSNp). ANOVA showed significant differences between groups (p < 0.05), except between the control and 3% TCSNp groups. Cell viability increased with higher TCSNp concentrations, with significant differences at 72 h between control and 5% TCSNp groups (p = 0.014). Mean DC values were 51.66% (control), 49.33% (1% TCSNp), 49.66% (3% TCSNp), and 48% (5% TCSNp). ANOVA indicated no significant differences between groups. Adding TCSNp to G2BU in SE mode maintains clinically acceptable SBS levels and enhances cytocompatibility. Higher TCSNp concentrations may reduce SBS and DC slightly. Further studies are needed to evaluate long-term effects.

Orthodontic bracket failure rate after bonding with and without primer – A systematic review and meta-analysis

To compare the difference in failure rates between orthodontic brackets bonded with light-cured primer and those bonded without primer. An electronic search of five databases and additional manual searches were performed until January 2024. Randomized and prospective non-randomized controlled trials directly comparing the bracket failure rate with and without primer. Two authors independently collected study characteristics by extracting outcome data from pre-defined sheets. After evaluating the risk of bias, the odds ratio and 95% confidence intervals (CIs) were calculated with random-effects models. Four studies were evaluated using qualitative and quantitative analysis. The analysis included data from 199 patients (1691 brackets with primer and 1646 brackets without primer). Random effects of pooled meta-analysis demonstrated statistically significant differences in the bracket failure rates (odds ratio=1.50, p=0.010, [95% CI 1.10 to 2.05]). The risk of failure was 1.5 times greater when brackets were bonded without primer. The results should be interpreted in the context of the limited sample size, even though there was a substantial difference in the failure rates of brackets with and without a primer, favouring the use of a primer. Furthermore, the validity of the finding may be limited by potential variables such as patient factors, clinician expertise, and isolation. More extensive research is required to validate these findings (PROSPERO CRD42024593134).

Effectiveness of high-frequency vibration, cotton rolls and elastomeric wafers in alleviating debonding pain of orthodontic metal brackets: a randomized clinical trial

This study aimed to evaluate the effectiveness of different pain mitigation methods during orthodontic debonding and to evaluate pain sensitivity across various regions of the dentition. A total of 144 participants (50 males and 94 females) with metal brackets were randomly assigned to one of four groups: High-Frequency Vibration (V), Cotton Roll (CR), Elastomeric Wafer (EW), and Open Mouth group (OM). Pain levels were measured using the Visual Analog Scale (VAS) across different sextants of the dentition. The Kruskal-Wallis test and post hoc analyses were conducted to compare VAS scores between groups. The Mann-Whitney test was used to analyse sex-based differences. The V group, utilizing high-frequency vibration, had the lowest total VAS score, indicating superior pain relief compared to CR, EW, and OM groups. No significant difference was observed between the CR and EW groups. Median VAS scores were highest in the lower front sextant, followed by the upper front sextants, and lowest in the posterior regions, indicating greater pain sensitivity in the anterior regions during debonding. High-frequency vibration was the most effective method for reducing pain during orthodontic debonding, particularly in the anterior dental regions. Both CR and EW methods were also effective but to a lesser extent. These findings suggest that high-frequency vibration could significantly improve patient comfort during orthodontic procedures. Utilizing high-frequency vibration for orthodontic debonding can enhance patient comfort, especially in the more sensitive anterior dental regions, thereby potentially improving treatment compliance and experience.Trial registration: NCT05904587.

The Biofilm Removal and Bactericidal Effect of an 810-nm High-Power Laser on an Orthodontic Bracket Surface: An In Vitro Study.

Objective: The present study aimed to analyze the biofilm removal and bactericidal effect of laser treatment alone and laser combined with ultrasonic scaling on orthodontic brackets. It also assessed whether the use of a laser can improve the efficiency of biofilm removal and bactericidal effect compared with traditional ultrasonic instrumentation. Background Data: Streptococcus mutans (S. mutans) can lead to white spots and dental caries. Orthodontic brackets make teeth cleaning more difficult, and biofilms or bacteria on the surface of brackets worsen the oral environment, which may cause some oral diseases. Laser can be used for biofilm removal and killing bacteria on the surface of an object through thermal, photochemical, and pressure effects, which is widely used in the treatment of oral diseases. Methods: A total of 600 mandibular incisor brackets were collected for this study. Among these, 320 unused brackets were used for the S. mutans crystal violet assay (n = 160) and for S. mutans live/dead bacterial staining (n = 160). Another 280 brackets, obtained from patients who had undergone therapy for over two years, were used for the mature multispecies biofilms removal assay (n = 120) and multispecies bacterial live/dead bacterial staining (n = 160). Ultrasonic scaling, laser, and laser combined with ultrasonic scaling were applied to the labial surface of brackets covered by S. mutans biofilm or mature multispecies biofilms. Specifically, we used the following three methods: ultrasonic scaling for 10 sec without laser; 810-nm laser (Doctor Smile, Italy, LA5D0 001.1) with 0.3-mm spot size at total 21.2 kJ/cm2 for 10 sec; and 810-nm laser at total 10.6 kJ/cm2 for 5 sec, followed by ultrasonic scaling for 5 sec. The 810-nm diode laser removed biofilms with a power of 1.5 W and a power density of 2.12 kW/cm2. The S. mutans biofilm was examined using crystal violet assay, and scanning electron microscopy (SEM) was used for mature multispecies biofilms to evaluate the effect of the three methods on biofilm removal. Live/dead bacterial staining was used to examine the bactericidal effect on remaining biofilms by confocal laser scanning microscopy (CLSM). Results: For S. mutans biofilm, the optical density (OD) value and live/dead bacterial ratio in the laser and the laser combined with ultrasonic scaling groups were significantly lower than those in the ultrasonic scaling group (p < 0.05); moreover, the OD value and the live/dead bacterial ratio in laser treatment combined with ultrasonic scaling and laser treatment alone showed no significant difference (p > 0.05). For mature multispecies biofilms, the percentage of biofilm coverage after treatment was higher in the laser group than in the ultrasonic scaling group (p < 0.05) and lower in the laser combined with ultrasonic scaling group than in the ultrasonic scaling group (p < 0.05), and live/dead bacterial staining showed that laser treatment alone killed the most bacteria, followed by laser treatment combined with ultrasonic scaling, while ultrasonic scaling alone seldom killed bacteria. Conclusions: Laser treatment alone has a better bactericidal effect and can also remove more S. mutans biofilm than ultrasonic scaling alone, but it fails to remove more mature multispecies biofilms. Laser treatment combined with ultrasonic scaling can remove more S. mutans biofilm and mature multispecies biofilms than ultrasonic scaling alone and also has a better bactericidal effect than ultrasonic scaling alone on a bracket surface.

Evaluation of the Conventional Acid-Etching System and the Self-Etching Primer in Bonding Metallic Orthodontic Brackets: An In-Vitro and In-Vivo Study.

This study aimed to compare the shear bond strength (SBS) of enamel-bonded orthodontic brackets with the conventional acid etching (CAE) system and the self-etching primer (SEP)in vitro and to compare the clinical performance of both systems when used in the treatment of malocclusion patients. In the first part of the study, 40 extracted human premolars were randomly divided into two groups containing 20 teeth. The first group (the conventional enamel etching group) employed37% phosphoric acid before bonding the metallic brackets (0.022-inch slot, MBT prescription, American Orthodontics, Sheboygan, WI, USA). The etching system wasTetric 5th (Ivoclar Vivadent, Schaan, Liechtenstein). The second group used a SEP (Sep Tetric 7th, Ivoclar Vivadent, Schaan, Liechtenstein) to bond the same brackets. In the first part of the study, SBS was evaluated, followed by the adhesive remnant index (ARI) assessment. The second part of the study (i.e., the clinical part) assessed a cohort of 30 patients during a 6-month observation period. The upper 10 teeth (from the second premolar on the right side to the second on the right side) were bonded using the chosen method for each patient in the clinical assessment. That is, 150 teeth in each group were evaluated regarding the failure rate. The ARI was assessed for those teeth that lost their brackets. The mean SBS was greater in the SEP group compared to the CAE group (17.93 MPa and 16.60 MPa, respectively; P = 0.014). The difference was not statistically significant. Conversely, the failure rate was lower in the CAE group compared to the SEP group, with a failure rate of 6% and 14.7%, respectively. The difference was statistically significant (P = 0.014). However, the ARI showed no statistically significant difference in in-vivo and in-vitro analyses, as most bracket failures were at the adhesive level. Laboratory results showed no statistical difference in the SBS mean values between the two groups. Clinically, the SEP group showed a greater failure rate than the CAE group, but both failure rates in the two groups were within the clinically acceptable range. The ARI did not show any difference between the two groups in terms of the failure site when the evaluation was conducted in vivo and in vitro, as most of the areas of failure were concentrated in the material itself.

Comparative Analysis of Shear Bond Strength in Orthodontic Brackets Between Milled and 3D-Printed Definitive CAD/CAM Restorations

Objective: The objective of this study was to evaluate the effect of different surface treatment methods on the shear bond strength (SBS) of metal brackets bonded to two types of CAD/CAM composite restorations: milled and 3D-printed. Materials and Methods: A total of 160 flat-shaped specimens (10 × 10 × 2 mm3) were prepared from four different CAD/CAM composites; two milled (Lava Ultimate™ [LU] and Grandio™ [GR]) and two 3D-printed (Crowntec™ [CT] and C&amp;B Permanent™ [CB]). These specimens underwent thermocycling (5000 cycles at 5–55 °C), then were categorized based on the surface treatment into four groups (n = 10): Group C (control, no surface treatment), Group HF (treated with 9.6% hydrofluoric acid), Group DB (mechanical roughening by a diamond bur), and Group SB (sandblasting using aluminum oxide). Metal brackets were bonded using Transbond XT Primer and universal adhesive, stored in artificial saliva for 24 h, then thermocycled again. Shear bond strength (SBS) was tested using a universal testing machine until bracket debonding occurred. The adhesive remnant index (ARI) was assessed using a stereomicroscope to quantify the residual adhesive following debonding. Result: Regarding material, GR and LU restorations had significantly higher SBS values compared to CT and CB, ranging from 13.90 MPa to 20.35 MPa. Regarding surface treatment, SB and HF groups showed significantly higher SBS values. The ARI scores showed different adhesive modes of failure, with higher instances of scores 0 and 1, which indicate no or minimal adhesive remaining. Conclusions: Both milled and 3D-printed materials had adequate SBS for clinical use, with milled materials showing superior results. Surface treatments like sandblasting and HF significantly improved bond strength, with adhesive failure being common.

In vitro determination of genotoxicity and cytotoxicity induced by stainless steel brackets with and without surface coating in cultures of oral mucosal cells

BackgroundOrthodontics is a speciality of dentistry that uses a plethora of devices made from myriad materials to manage various malocclusions. Prolonged contact of orthodontic appliances with oral tissues can lead to cellular damage, highlighting the need for biocompatible materials to mitigate health risks.ObjectivesTo analyze the genotoxicity and cytotoxicity produced by metal brackets and coated metallic brackets with polymeric and nanoparticle coatings in oral mucosal cells.Materials & methodsThe current study compares the toxicity of 3 different types of orthodontic brackets with control groups of oral mucosal cells. Each of the three treatment groups consisted of 10 samples of orthodontic brackets: stainless steel brackets(Group 1), nanoparticle-coated brackets(Group 2), and polymeric-coated brackets(Group 3) exposed to corrosion eluates employing an oral biomimicry model. Two types of oral mucosal cells- Human Gingival Fibroblasts and Buccal Epithelial Cells were used to study the cytotoxic and/or genotoxic effects of the elutes. Intergroup comparisons were conducted using one-way analysis of variance, while scanning electron microscopy evaluated surface characteristic.ResultsThe interaction between metal ions and oral mucosal cells showed no statistically significant difference for toxicity assays between the three groups(p > 0.005). However, polymeric and nanoparticle-coated groups showed reduced cellular differentiation when compared with conventional stainless-steel brackets.ConclusionThis in-vitro study shows that polymeric or nanoparticle coating of conventional metal brackets aids in enhancing corrosion-resistant characteristics of orthodontic appliances and reduces the toxic oral environment created by metal release in the oral cavity.

Comparison of Friction Resistance Between Different Bracket Systems: An In Vitro Study

Introduction The efficiency of tooth movement associated with orthodontic sliding mechanics can be compromised by friction between archwire and tube or bracket slot. Orthodontic brackets and archwires are important constituents of an orthodontic appliance system. Friction is an uncontrolled variable of particular interest when continuous arch techniques are used to align and move teeth by way of sliding a tube or bracket along an arch. Aim and Objectives Comparison of frictional resistance between different bracket systems of 3M and MO brands in combination with different wires of 3M, MO, and G&amp;H brands. Evaluation of frictional resistance between two different types of bracket systems and different types of wire combinations. Materials and Methods Two types of bracket systems were used: metal bracket system and ceramic bracket system (3M and MO brands). Four different orthodontic wire alloys were used: stainless steel (SS), TMA, NiTi, and CuNiTi (3M, MO, and G&amp;H brands). A rectangular block made up of self-cure acrylic resin was designed to hold the bracket during the mechanical test. Each bracket base was glued to an acrylic block with cyanoacrylate glue. The wire segment was inserted into the bracket and was ligated passively with SS ligature wire. The bracket–wire combination was submitted to mechanical tests with a universal testing machine. One end of the acrylic block was mounted to the lower grip of the universal testing machine. The free end of the archwire was fixed to the upper grip of the universal testing machine. The friction which was generated between the wire and bracket was measured under dry conditions and at room temperature. The test wire was pulled through the bracket at a speed of 0.5 cm/min. The load cell registered a maximum force level. This data was stored in the computer and was submitted to statistical analysis, and parameter tests were applied. Results The highest mean friction resistance of 5.998 N was generated by group B2-E2 (ceramic bracket – MO + TMA archwire – MO). The lowest mean friction resistance of 2.552 N was generated by group A1-C1 (metal bracket – 3M + SS wire – 3M). There was a statistically significant difference between the friction generated by the metal bracket on SS archwire and the ceramic bracket on TMA archwire regardless of 3M or MO brand material ( p value &lt; .0001) and metal bracket ( p = .0004).

The Mechanical and Clinical Properties of Customized Orthodontic Bracket Systems-A Comprehensive Review.

The rise of computer-aided design and computer-aided manufacturing (CAD/CAM) and 3D printing technologies in orthodontics has revolutionized the development of customized labial and lingual bracket systems with a variety of materials, which offer potential advantages over traditional orthodontic brackets. To highlight the current state of knowledge regarding the mechanical and clinical properties of CAD/CAM and 3D-printed custom bracket systems, we conducted a comprehensive search across the PubMed, Embase, Cochrane Library, Web of Science, and Scopus databases to identify relevant articles published before April 2024. Mechanical (including fracture toughness, hardness, modulus of elasticity, frictional resistance, slot accuracy, torque transmission, and shear bond strength) and clinical (including treatment efficiency and duration, cost, and comfort) properties were compared between traditional and customized orthodontic bracket systems in the current review. Our findings suggest that customized brackets have the potential to increase bracket slot precision, reduce treatment time, and offer cost-efficiency. However, it is worth noting that the advantages and disadvantages of customized bracket systems vary depending on the bracket material and the manufacturing methods, warranting comprehensively controlled investigations in the future.

The effect of addition of Bioglass 45S5 to orthodontic adhesive on shear bond strength of metal orthodontic brackets, An in vitro study

Aim: This study aimed to evaluate the effect of incorporating Bioglass (BG) 45S5 into an orthodontic adhesive on the shear bond strength (SBS) of metal orthodontic brackets bonded to enamel and the adhesive remnant index (ARI) score. Methods: In this in vitro study, 55 extracted sound premolars were randomly divided into five groups (n=11 each). Metal brackets were bonded using Ambar FGM orthodontic adhesive without BG (control group) and with BG 45S5 added at concentrations of 5%, 10%, 15%, and 20% by weight in groups 2 to 5, respectively. The SBS was measured using a universal testing machine, and the ARI score was determined under a stereomicroscope at ×10 magnification. Data were analyzed using one-way ANOVA at a significance level of α=0.05. Results: The highest mean SBS was observed in the 20% BG Group (48.28±24.5 MPa), followed by the control group (35.81±11.11 MPa), 15% BG Group (19.64±5.42 MPa), 10% BG Group (16.3±9.33 MPa), and 5% BG Group (14.21±4.23 MPa). The SBS in the 20% BG Group was significantly higher than in the control (P=0.013), 5% BG (P=0.000), and 10% BG (P=0.002) groups. No significant differences were found in ARI scores among the groups (P=0.810). Conclusion: Adding BG 45S5 to the orthodontic adhesive at concentrations of 5%, 10%, and 15% did not significantly affect the SBS, but a 20% concentration increased the SBS. Incorporating BG at these levels does not adversely impact the SBS or ARI scores.

Comparison of static teeth exposure in different postures and its influencing factors of orthognathic surgery patients.

This study aimed to explore the differences and influencing factors of static teeth exposure in different postures of orthognathic surgery patients. A total of 148 patients were collected before or after orthognathic surgery. Photographs were taken in the upright and supine positions, and the static teeth exposure values were measured to compare whether the difference among different positions was statistically significant. The patients were classified in accordance with gender, presence or absence of orthodontic brackets, measurement time (preoperative or postoperative), and maxillary movement direction (forward or backward), and the difference of static teeth exposure was compared. The correlation between the difference of static teeth exposure and age was analyzed. The diffe-rence of static teeth exposure between the two positions was 0.99 mm±0.95 mm, which was statistically significant (P=0.000). A statistical difference in the difference of static exposure was observed between female and male (P<0.05). No statistical difference in the difference of static exposure was observed among orthodontic brackets, preoperative or postoperative time points, and maxillary movement direction. In addition, no significant correlation was found between the difference of static teeth exposure and age (r=-0.087, P=0.291). Compared with the upright position, the static exposure of teeth increased by approximately 0.99 mm in the supine position. The difference of static exposure under different postures was greater in males than in females. Furthermore, orthodontic bracket, maxillary surgery, maxillary movement direction, and age had no effect on the difference of static teeth exposure in different postures.

The effect of different enamel surface treatment methods on the shear bond strength between self-adhesive resin composite and orthodontic brackets

The effect of different enamel surface treatment methods on the shear bond strength between self-adhesive resin composite and orthodontic brackets

Impact of clear aligners and different esthetic orthodontic brackets on enamel demineralization (A comparative SEM study)

Impact of clear aligners and different esthetic orthodontic brackets on enamel demineralization (A comparative SEM study)

Effects of beverages on Bond Strength of Orthodontic Brackets

Effects of beverages on Bond Strength of Orthodontic Brackets

Comparison of Bracket Failure with Resin Modified Glass Ionomer Cement and Resin-Based Adhesive

A high strength of bonding materials is needed for orthodontic attachments to sustain therapeutic forces and patients’ masticatory habits. Objectives: To compare the bond strength of the resin modified glass ionomer cement (RMGIC) and resign based adhesive system which leads to bracket failure in orthodontic treatment (failure to bracket attachment) for the duration of 6 months at the a tertiary care hospital at Hyderabad, Sindh Pakistan. Methods: This comparative cross-sectional study involved 30 patients, each with 20 brackets, using non-probability sampling. Participants were between the ages of 13 and 30 with fully erupted permanent teeth and mild skeletal discrepancies. Quadrants were randomized, and 120 attachments were placed in total, split evenly between the two types of materials. The study involved bonding orthodontic brackets using either composite resin or RMGIC. The teeth were prepared and cleansed, and the brackets were bonded following standard procedures. Patients were monitored each month for six months (six visits) to check for any debonded or missing brackets. Chi-Square test was run to compare bracket failure between two groups. Results: There were significant differences in bracket failure rates between the composite and RMGIC sides. Composite had a lower failure rate, with 90% of brackets remaining intact compared to 63.3% with RMGIC (p=0.04). Gender comparisons showed both male and female participants experienced more failures with RMGIC than with composite, with p-values of 0.039 and 0.038, respectively. Conclusion: RMGIC could not withstand the forces experienced during fixed appliance treatment as effectively as composite resin, resulting in a higher debonding rate.

Evaluation of Etching Time Effect on Shear Bond Strength of Orthodontic Brackets Bonded with Self-Adhesive Composite: An in-Vitro Study

Introduction: Precise acid etching of the tooth surface is a significant factor in the strength of the bracket bond. The current study aimed to determine the effect of different application times of acid etching on the shear bond strength of metallic orthodontic brackets under controlled laboratory conditions. Methods: Sixty intact premolar teeth were selected for this in-vitro study. The samples were divided into four groups based on the different acid etching times: 20, 25, 30, and 35 seconds. The teeth surfaces were etched with 37% phosphoric acid according to the specified times, and brackets were bonded to the enamel surface using GC Ortho connect composite. Shear bond strength values of the brackets was measured using a Universal Testing Machine. The amount of Adhesive Remnant Index was also observed using a stereomicroscope. Additionally, the surface roughness of the tooth enamel after bracket bonding was examined using SEM. The results related to shear bond strength were analyzed with one-way ANOVA statistical test and using SPSS version 16 software. The non-parametric Kruskal Wallis (Wallis-Kruskal) test was also used to check the frequency of ARI index. Results: The highest shear bond strength was observed at 25 seconds, and the lowest at 30 seconds. However, there was no significant difference in the shear bond strength of brackets was observed among the four groups (p=0.186). The highest ARI score was observed at 35 seconds, and the lowest at 20 seconds. No statistically significant difference was observed in the ARI scores in different groups. SEM images revealed that the enamel surface porosity was highest at 20 seconds. Conclusion: The results indicate that the shear bond strength and ARI at different acid etching times do not significantly differ. Therefore, orthodontic bracket bonding can be performed with less acid etching time.

Direct versus fully digital indirect bracket bonding: a split-mouth randomized clinical trial on accuracy

ObjectivesThe primary aim is to assess differences in accuracy of orthodontic bracket positioning between fully digital indirect bracket bonding (IDB) and conventional direct bracket bonding (DBB). The secondary aims are to assess differences in bracket bonding failures, bracket repositioning need, clinician experience and patient satisfaction.Materials and methodsThis prospective study was designed as a split-mouth randomized clinical trial. In total, 35 patients were analyzed with a six month follow-up period. Translational and orientational deviations from the planned bracket position were determined. Clinician experience and patient satisfaction were evaluated by means of a survey.ResultsThe difference in translation was 0.34 mm (95% CI: 0.238–0.352, p = 0.017), the difference in orientation was 4.80˚ (95% CI: 3.858–5.727, p < 0.001), both in favour of IDB. IDB showed significantly more immediate (IDB: 3.9%, DBB: 0%) and late (IDB: 5.4%, DBB: 2.5%, p = 0.008) bonding failures. Clinicians and patients experienced a shorter clinical chair time with indirect bonding over direct bonding.ConclusionsIDB bracket positioning leads to significant smaller translation and orientation deviations from digital IDB planning, than DBB bracket positioning. However, IDB leads to more immediate bonding failures than DBB. The majority of patients preferred IDB over DBB, due to a shorter clinical chair time.Clinical relevanceThis study adds to the knowledge of IDB in orthodontics and contributes to evidence on this technique. This evidence is applicable in everyday orthodontics, with respect to patient satisfaction and technical limits of IDB. The trial was registered in the Dutch Trial Register and the International Clinical Trials Registry Platform (ICTRP) of the World Health Organization (WHO), number NL9411.

Evaluation of Mechanical and Elemental Properties of Bioceramic-Coated Orthodontic Brackets and Enamel Surface.

The aim is to coat orthodontic brackets with two different bioactive materials and to compare the mechanical and morphological properties of coated brackets and tooth surfaces. A total of 120 stainless steel brackets were divided equally into three groups, that is, the uncoated brackets and nanohydroxyapatite (nHA)-coated, and nanobioactive glass (nBG)-coated brackets using a spin coater machine. The brackets were bonded on the enamel surface and underwent remineralization/demineralization cycles for days 1, 7, 14, and 30. At each time interval, the bond strength of the brackets was assessed using mechanical loading. An optical and scanning electron microscope (SEM) were used for surface evaluation, and the adhesive remanent index (ARI) values were obtained and quantified. One-way analysis of variance using Tukey's test was used to compare the differences among the groups. A uniform distribution of nanoparticles occurred on the surfaces of brackets. The shear bond strength (SBS) showed no significant differences in any tested groups on days 1, 7, and 14. However, control and nBG showed a significant difference from nHA at day 30. On days 7, 14, and 30, the nHA group showed the highest SBS values among the groups. For ARI, most samples showed an adhesive nature of failure at the enamel-brackets interface. The images confirmed the presence of coated particles on brackets and remnants of adhesives after SBS. This study confirmed that the nHA- and nBG-coated brackets have a high potential for application in orthodontics regarding structural and mechanical properties.

Shear Bond Strength of Orthodontic Brackets to Resin-Infiltrated Enamel

Abstract Objectives This study aims to evaluate shear bond strength (SBS) of orthodontic brackets to enamel after resin infiltration pretreatment using different adhesive systems. Materials and Methods Sixty extracted maxillary first premolars were divided into five groups (n = 12). Group I: sound enamel + Transbond XT; group II: resin-infiltrated enamel (ICON) + Transbond XT; group III: ICON + Scotchbond Universal Plus; group IV: ICON + Assure PLUS; group V: ICON + Transbond Plus Self Etching. The SBS was measured using universal testing machine and analyzed using analysis of variance (ANOVA). The adhesive remnant index (ARI) score after debonding was determined under stereomicroscope with a 10× magnification. Statistical Analysis A one-way ANOVA and post hoc Tukey's test were used to compare the data. Further, the ARI scores were evaluated using a chi-squared test. The level of significance was set at p = 0.05. Results SBS of group I, II, III, IV, and V were 11.70 ± 3.17, 11.23 ± 3.06, 9.52 ± 1.73, 8.97 ± 1.12, and 9.14 ± 0.70 MPa, respectively. SBS of group IV and V was significantly lower than group I and II (p &lt; 0.05). There was no significant difference in the ARI scores among the five groups (p &gt; 0.05). Conclusion The SBS of enamel resin infiltration pretreatment depends on the adhesive system. The SBS of all groups was within adequate SBS range in clinical use. The most common ARI score was 2, which indicated lower risk of enamel fractures when debonding.

Evaluation of dimensional accuracy and surface roughness of lingual bracket slot –An in vitro study

The paradigm shift with the increasing number of adults and teens seeking aesthetic options for orthodontic treatment led to the increased demand for lingual orthodontics. When it comes to size and slot dimensions, lingual brackets are very different from labial brackets.With the rise of lingual orthodontics in our everyday practice, it's more critical than ever for practitioners to understand these potential bracket size variations. The resistance to sliding mechanics can occur if the contact angle between the archwire and bracket increases, this creates the need for precise bracket slot dimension. The amount of friction varies proportionally to the accuracy of the dimensions and the roughness of the bracket slot.To evaluate the precision of commercially available orthodontic lingual bracket slots in inch dimensions with manufacturers’ published dimensions using a stereomicroscope and to compare the surface roughness of commercially available orthodontic lingual bracket slots using an atomic force microscope.Lingual brackets from four different manufacturers were taken for evaluation of slot dimensions. Twenty brackets of each manufacturer were randomly selected. Trinocular Stemi 2000 Stereo Zoom Microscope with Digital Camera (Carl Zeiss, Germany) was used for measurement of bracket slot dimensions. An atomic Force Microscope (AFM) (Nanoscope® IV Di digital instrument, California, USA) was used to evaluate the surface roughness of lingual bracket slots. Comparison of dimensions between mesial processes and comparison of dimensions between distal processes showed that the difference was only marginal with no significant statistic value. Statistically significant results proved that slot dimensions were not precise as per the manufacturer’s standards for given lingual brackets and were oversized for all bracket systems. Statistically insignificant results showed that the bracket systems were similar concerning the surface roughness of the bracket.The analyzed series of lingual bracket systems exhibited significant differences with manufacturers’ standards in slot dimension, which will clinically result in torque play. Lack of standardization of slot dimensions during the manufacturing process may be clinically associated with undesirable tooth positioning and movement; inferring that the bracket systems were similar concerning the surface roughness of the bracket slot.