Top PDF Effect of Adhesion Promoter on Bond Strength of Reconditioned Brackets – an In vitro Study

Effect of Adhesion Promoter on Bond Strength of Reconditioned Brackets – an In vitro Study

Effect of Adhesion Promoter on Bond Strength of Reconditioned Brackets – an In vitro Study

Sandblasting the bracket base has been shown to increase the bond strength of new brackets to enamel by removing unfavorable oxides, contaminants on the base, and increasing surface roughness and surface bonding area [18,19]. Sandblasting of debonded brackets produced comparable bond strengths to new brackets and is considered to be the best method of recycling giving the highest shear bond strength values in recycled bracket groups [1,3]. The results of this study also showed the mean bond strength of sandblasted rebonded brackets (group B, 6.39 MPa) was significantly lower than new brackets (group A, 9.58 MPa). Algera investigated the influence of different bracket base pretreatments in relation to three different types of cement, Transbond XT, a resin composite, Fuji Ortho LC, a resin-modified glass ionomer cement (GIC), and Fuji IX Fast, a conventional glass ionomer cement, on shear as well as on the tensile bond strength. Upper incisor brackets with three types of base treatment, sandblasted, silicoated, and tin-plated, were bonded to bovine enamel and tested. They found no clear improvement in relation to the pretreatments of the bracket bases and emphasized that other factors are responsible for the resistance to fracture [20].
Show more

7 Read more

Effect of two different primers on the shear bond strength of metallic brackets to zirconia ceramic

Effect of two different primers on the shear bond strength of metallic brackets to zirconia ceramic

The second null hypothesis, that is, that there is no statistically significant difference in shear bond strength between the wire-activated test group and the non-activated control group has to be rejected for the Monobond S group but has to be accepted for the Monobond Etch & Prime group. However, it should be noted that due to the low adhesion values of less than 1 MPa found in this study when using Monobond S with- out hydrofluoric acid, this statistical finding is irrelevant. Hence, a clinical use with these low adhesion values can- not be recommended. With regard to the different posi- tions of the brackets in the simulated leveling phase of the orthodontic treatment, end position versus position in the middle, the null hypothesis has to be accepted, re- gardless of the adhesive material used. Thus, there are no different shear bond values when the bracket is sub- jected to a force from two sides (the bracket in the mid- dle), or only from one side (the bracket on the end). This finding might seem faulty from the physical point of view, but it might be due to the low forces exerted by
Show more

8 Read more

Effect of Time on Bond Strength of Lingual Brackets in Indirect Bonding with Different Base Composite and Sealant Combinations: An In Vitro study

Effect of Time on Bond Strength of Lingual Brackets in Indirect Bonding with Different Base Composite and Sealant Combinations: An In Vitro study

T. M. Hodge et al in 2004 30 , compared the accuracy of direct and indirect bonding techniques in 26 patients who required upper and lower full arch fixed appliances using preadjusted edgewise brackets with a 0.022-inch slot. According to a split mouth system of allocation the brackets were bonded directly or indirectly and photographs were made before and after bond-up to determine the differences from the ideal. Results showed that there is no difference between mean bracket placement errors for direct or indirect methods and the range of error in three directions assessed were greater for direct than indirect placement.
Show more

114 Read more

Effect of enamel protective agents on shear bond strength of orthodontic brackets

Effect of enamel protective agents on shear bond strength of orthodontic brackets

In the current study, using the caries infiltrant (ICON) before bonding did not significantly change the bond strength compared to the other groups, although the bond strength was lower when self-etching primer was used than when phosphoric acid was used for enamel preparation before bonding. This was also observed in the control group; shear bond strength was lower when self-etching primer was used than when phosphoric acid was used, but this difference was statistically insignifi- cant. Previous studies found a significant increase in the shear bond strength of Transbond XT adhesive with phosphoric acid and Transbond XT primer when ICON was used before bonding orthodontic brackets to sound enamel [36] or even to demineralized enamel [37]. The shear bond strength was also increased when Transbond Plus Self Etching Primer was used instead of the conven- tional phosphoric acid etching to sound enamel [36]. The shear bond strengths recorded in this study were sufficient for clinical use in all the six groups presenting different combinations of adhesive systems and enamel protective agents as well as control groups. The average range of bond strength was suggested by Reynolds [38] to be 5.9 to 7.8 MPa for clinical and 4.9 MPa for laboratory performances. In vitro and in vivo stud- ies of SBS are both needed; in vitro measurements of shear bond strength provide useful information about the bonding efficiency of different types of materials, but the actual performance of these materials can only be evaluated in the environment where they were intended to function [39]. Unfortunately, no one variable or combination of variables that can be mea- sured in the laboratory is perfectly predictive of what might occur when the bonding adhesive is used in the demanding environment of the oral cavity [40-42]. Therefore; in vitro studies are mainly important as a preliminary guide to the clinician, while in vivo stud- ies are needed for evidence-based practice.
Show more

6 Read more

Factors Affecting the Shear Bond Strength of Orthodontic Brackets – a Review of In Vitro Studies

Factors Affecting the Shear Bond Strength of Orthodontic Brackets – a Review of In Vitro Studies

Several studies have compared the SBS of orthodontic brackets according to acids used for etching, etchant concen- tration, duration of etching and variation in etching pattern. Olsen et al. (12) compared the effects, on SBS and bracket failure location, of two adhesives and two enamel condition- ers (37% Phosphoric acid and 10% Maleic acid). The results showed no significant difference in the mean SBS among the four groups. Carstensen (13) evaluated the effect of differ- ent Phosphoric acid concentrations on the SBS of brackets bonded to enamel. The three concentrations examined were 37%, 2% and 5%. This study reported that, the mean SBS after etching with 37% acid was significantly higher than that after etching with 2% Phosphoric acid. The effect of etch time and debond interval upon the SBS of metallic or- thodontic brackets was studied by Bin Abdullah and Rock (14). The 3 different etching time studied were 15, 30, or 60 seconds and the 3 different debonding time evaluated were 5 or 15 minutes, or 24 hours. The lowest mean SBS was observed in the group of specimens etched for 15 seconds and debonded after 5 minutes. The possible difference in the SBS to acid etched enamel on the different teeth of the dentition was investigated by Hobson et al. (15). The results showed that tooth type had a significant effect on the SBS, with the greatest mean SBS found on the lower first molar teeth and lowest on the upper first molar teeth. Furthermore, the mean SBS was higher on anterior teeth compared to posterior teeth in the upper arch whereas, it was lower on the anterior teeth compared to posterior teeth in the lower arch.
Show more

6 Read more

Effect of Quaternary Ammonium Salt on Shear Bond Strength of Orthodontic Brackets to Enamel

Effect of Quaternary Ammonium Salt on Shear Bond Strength of Orthodontic Brackets to Enamel

A previous study showed that addition of QAS to composite resin caused no change in shear bond strength of brackets after one month [8]. This finding was in agreement with our results since we found no significant difference in shear bond strength of the groups containing QAS and the control group. No standard method exists for assessment of bracket bond strength to tooth structure because in the clinical setting, loads applied to brackets are complex and include a mixture of shear and tensile loads, which cannot be well simulated in vitro. However, shear bond strength test is often performed for this purpose [15] and was adopted in the current study as well. The results showed that by an increase in concentration of QAS, no significant reduction occurred in shear bond strength. Several factors affect the bracket bond strength to tooth structure including the type of adhesive, type of bracket, clinician’s expertise and patient’s cooperation [16].
Show more

6 Read more

Effects of at-home and in-office bleaching on the shear bond  strength of metal, ceramic and composite brackets to enamel: An In vitro study

Effects of at-home and in-office bleaching on the shear bond strength of metal, ceramic and composite brackets to enamel: An In vitro study

Wiltshire et al (2010) mentioned that debonding force is determined from the load drop on the mechanical machine and reported in units of Newtons (N), kilogram (kg), or pounds (lb). Bond strength is defined as the force of debonding divided by the area of the bonded interface measured in units of megapascals (MPa), kilograms per square centimeter (kg/cm 2 ), pounds per square inch (lb/in 2 or psi). It is difficult to estimate the optimal bond strength of an adhesive in the oral environment. This is because the orthodontic brackets are subjected to masticatory forces, which are often a mixture of shear, peel, shear-peel, and tensile force. Rather than focusing on an arbitrary numerical “clinical acceptable bond strength”, they suggested to pay more attention to potential damage to the enamel, especially when the bond strength is too high. They recommended mean bond strength of at least 3 - 4MPa in vitro for minimal reliable clinical bonding. (72)
Show more

111 Read more

Comparative Evaluation of Shear Bond Strength of Orthodontic Brackets on Pretreatment with CPPACP, Fluor Protector and Phosflur: An In-vitro Study

Click here to download PDF version of the article !

In an earlier study conducted by Dunn it was suggested that Orthodontic brackets bonded to teeth with an ACP containing composite material failed at significantly lower forces than brackets bonded to teeth with conventional resin-based composite Ortho- dontic cements. So the question that arises is whether the dis- advantage of low bond strength due to the effect of the material outweighs its advantage as a protector against demineralization. Recent studies however show that CPP-ACP application can cause increased shear bond strength of brackets when light-cured adhesive is used. In this in vitro study the effects of pretreatment of CPP-ACP on Shear bond strength (SBS) of Orthodontic brackets was examined.
Show more

5 Read more

Comparison of Shear Bond Strength of Different Orthodontic Metal Bracket-bases Bonded on Enamel Surface – an In vitro Study

Comparison of Shear Bond Strength of Different Orthodontic Metal Bracket-bases Bonded on Enamel Surface – an In vitro Study

The shear bond strength also depends on the adhesive materials. Transbond XTTM is one of the most recommended products in current orthodontics. It has been a part of various comparative adhesion studies. In this study, all data were obtained with Transbond XTTM, which strongly associated with previous studies [26-29]. Reynolds and von Fraunhofer [30] stated that all the retentive designs used in the brackets tested should have an acceptable bond force levels (6– 8 MPa). However, there are various factors related to an oral environment or moisture contamination that may affect the shear bond strength. The moisture contamination of bracket- bases with water, saliva and blood has been shown to adversely affect the shear bond strength due to deposits of an organic adhesive layer immediately after exposure that is resistant to washing and subsequently it reduces the shear bond strength of brackets [17,31-33]. Ahmad Sheibaninia et al. [34] evaluated the effect of an acidic food simulating environment on shear bond strength of self-ligating brackets and stated that the margins of bracket-bases allows an acidic food to penetrate, which gradually decreases the shear bond strength. So care should be taken in predicting the results to those conditions. Arunima Goswami [35] et al. stated that moisture contamination did not affect the shear bond strength. It has been suggested that an adverse effect of moisture contamination on orthodontic bonding can be associated with water adsorption, which produce formaldehyde
Show more

9 Read more

Comparison of Shear Bond Strength after Thermocycling of Brackets Bonded using Two Different Moisture Insensitive
Primers: An In Vitro Study

Comparison of Shear Bond Strength after Thermocycling of Brackets Bonded using Two Different Moisture Insensitive Primers: An In Vitro Study

Over the years a great deal of attention has been paid to improve the acid- etching technique, primers and adhesives. Nonetheless, adhesive failures still exist because of contamination during bonding. Traditional bond materials must be applied in completely dry and isolated fields to achieve adequate bond strength. Hydrophilic bond systems have been an important development in orthodontic practice because many routine clinical procedures are not carried out under ideal conditions. In particular, it can be difficult to bond attachments to hard-to-reach places such as the gingival area, second molars, and partially erupted or impacted teeth 56,67,77,126 . In these cases, bonding failure is common, and rebonding, which consumes chair time and is a burden for both orthodontist and patient, becomes necessary 126 . In unsuccessful bonding procedures, most of the porosities produced by the enamel acid-etch procedure become plugged with moisture. As a result, resin penetration is impaired, and when insufficient numbers and lengths of resin tags form, bond strength is compromised 96,128,135 . Contamination of the enamel surface therefore necessitates the etching procedure to be repeated to ensure the adequate bonding of composites 96 . For this reason, several studies have evaluated the effects of contaminants like water, saliva, and blood on SBS 32, 67,126,169 .
Show more

115 Read more

The Effect of Four Surface Treatment Methods on the Shear Bond Strength of Metallic Brackets to the Fluorosed Enamel

The Effect of Four Surface Treatment Methods on the Shear Bond Strength of Metallic Brackets to the Fluorosed Enamel

lowed by acid in severe fluorosis provided adequate SBS for fixed orthodontic appliance, but the use of this treatment could not improve bond strength in case of moderate fluorosis. Suma et al. [19] stated that com- bining air abrasion with acid etching created greater SBS than acid etching alone in moderate to severe dental fluorosis regardless of the adhesion system used. They used air abrasion at air pressure of 80 PSI, and the teeth were etched for 60 seconds after air abra- sion. The duration of acid etching and air pressure employed in this study was higher than our study and these may be the factors responsible for different result. Findings of the current study demonstrated that bond strengths were significantly weaker when the tooth surfaces were prepared with the Er:YAG laser followed by acid etch compared with other enamel surface treat- ments; it was in line with the findings of Lee et al. [23] This might be due to the reduced surface area and pore volume in the enamel surface after laser ablation. [29] The lower bond strength observed in the laser followed
Show more

9 Read more

Effect of different preventive agents on bracket shear bond strength: in vitro study

Effect of different preventive agents on bracket shear bond strength: in vitro study

as a result of topical exposure to CPP-ACP showed more resistant to subsequent acid etching [32]. Hirce et al. [35] supported the use of topical fluoride after acid-etching, a procedure that achieves the benefits of increased fluoride uptake without changing the bond strength of the resin adhesive. Although, application of preventive agents after acid-etching resulted in higher SBS value than when applied before acid-etching, there was no significant difference in the SBS between the control and the other experimental groups when applied before acid-etching. This indicated that the application of these preventive agents before acid-etching has no adverse effect on bracket bonding strength. This was in accordance with Xiaojun et al. [18] who found that the use of CPP-ACP before acid-etching did not compromise the bracket bond strength. Tabrizi and Cakirer [12] found also that application of CPP-ACP, either alone or combined with fluoride before acid-etching may safely be used as a prophylactic agent prior to bracket bonding. In addition, Park et al. [24] reached a similar conclusion regardless of the adhesive system used for bond brackets on the teeth. Furthermore, Çehreli et al. [25] reported that the application of CPP-ACPF before acid-etching has no effect on bracket SBS when using self-etching systems, but when applying its non-fluoride version CPP-ACP, significant decrease in bracket SBS was evident. Contradictory to our result, Kecik et al. [28] observed that the application of CPP-ACP alone or combined with acidulated phosphate fluoride (APF) has shown significant increase in the SBS of orthodontic brackets.
Show more

6 Read more

Effects of different chlorhexidine pretreatments on adhesion of metal brackets in vitro

Effects of different chlorhexidine pretreatments on adhesion of metal brackets in vitro

interfere with the bonding procedure. Adsorption of CHX by the enamel and remnants of CHX that are ex- pected to prolong antibacterial agent release over time might limit direct contact of the etching agent resulting in incomplete etching [10]. Numerous studies have investigated the possible effects of different CHX appli- cations on the adhesion of brackets. CHX was tested in all three forms under following conditions: before acid etching without subsequent surface cleaning; after en- amel etching mixed with bonding agent; after enamel etching alone, without additional bonding agent; after enamel etching prior to photo-polymerization of the bon- ding agent; after enamel etching following the photo- polymerization of the bonding agent and mixed with bonding agent on hydrophilic primer applied etched en- amel [10-16]. No adverse effect was reported when CHX with low concentrations was applied prior to acid etching but controversial results were reported following applica- tions after acid etching where only mixing CHX varnish with the bonding agent was agreed to be a safe application by the researchers [10,11]. On the other hand, there is no information in the literature investigating the possible effects of CHX application modes with various concentra- tions on adhesion of brackets. Moreover, there is no ma- nufacturer instruction clarifying the appropriate mode of application and the state of bonding area prior to bracket placement, which is directly influential on persistence of bacterial suppression. Theoretically, adhesion might get affected by the presence of CHX on the enamel surface depending on its form and concentration [10,16]. To test this question, the aim of this present study was to investi- gate the influence of various pre-treatments with CHX ap- plied according to manufacturer instructions on adhesion of brackets prior to bracket placement and observe the failure types following debonding. The hypothesis tested was that CHX pre-treatments that were removed from the surface prior to bonding procedures would have no ad- verse effect on the adhesion of metal brackets.
Show more

5 Read more

Effect of remineralizing agents on bond strength of orthodontic brackets: an in vitro study

Effect of remineralizing agents on bond strength of orthodontic brackets: an in vitro study

Very limited studies have been found to be conducted to evaluate the effect of fluoride and CPP-ACP on the bond strength. Also, studies conducted have shown con- troversial results. In a study conducted by Damon et al. [11] and Bishara et al. [12], the shear bond strength was not affected by various concentrations and methods of application of fluoride. However, the study conducted by Tabrizi and Cakirer [13] concluded that no significant difference was seen between control, CPP-ACP, and CPP-ACP with fluoride group, while fluoride application caused a significant decrease in the tensile bond strength of etch and rinse bonding technique. Kecik et al. [14] compared the effects of CPP-ACP and acidulated phos- phate fluoride on SBS values and found higher SBS values for all test groups. Xiaojun et al. [15] reported higher SBS in the CPP-ACP applied group when light-cure adhesives were used. In a study conducted on demineralized en- amel by Uysal et al. [16], fluoride and CPP-ACP en- hanced the bond strength of the orthodontic brackets compared to the control group in demineralized en- amel. In contradiction to this, Ekizer et al. [17] showed no significant difference in fluoride group and control group, while CPP-ACP enhanced the bond strength of the orthodontic brackets.
Show more

8 Read more

Effect of Cyclic Loading on Shear Bond Strength of Orthodontic Brackets:  An In Vitro Study

Effect of Cyclic Loading on Shear Bond Strength of Orthodontic Brackets: An In Vitro Study

In the present study, 84 extracted bovine mandibular incisors were selected and disinfected by immersion in 0.5% chloramine T solution at 4°C for one week after removing the soft tissue remnants and debridement. The teeth were caries-free and had no apparent defects or enamel damage. Although bovine and human teeth are different, studies have shown that there is no significant difference in adhesive bond strength to enamel between the two [12,13]. The roots of the teeth were cut, and the crowns were stored in distilled water at 4°C until testing. The teeth were randomly divided into two groups for use of total-etch (Transbond XT; 3M Unitek Orthodontic Products, Monrovia, CA, USA) and self-etch (Transbond Plus; 3M Unitek
Show more

7 Read more

Does the antioxidant treatment affect the shear bond strength of orthodontic brackets: An in vitro study

Does the antioxidant treatment affect the shear bond strength of orthodontic brackets: An in vitro study

essential for them to assess whether bleaching has had any effect on the shear bond strength of orthodontic bracket adhesives on the tooth surface. There thus arises a need for orthodontists to seek and practise ways of reversing the effect of bleaching so that efficient and successful orthodontic treatment outcomes are achieved. A significant reduction in the shear bond strength of composite resin to enamel after bleaching with 35% hydrogen peroxide has been reported in previous studies by Cavalli et al. 12 and Nour El-din etal. 13 Hence, the present
Show more

5 Read more

FORMULATION AND IN VITRO EVALUATION OF DISSOLVING BUCCAL FILMS OF LOVASTATIN

FORMULATION AND IN VITRO EVALUATION OF DISSOLVING BUCCAL FILMS OF LOVASTATIN

The purpose of this investigation was to develop “Dissolving muco- adhesive buccal films” of lovastatin by solvent casting technique to deliver lovastatin into blood via buccal mucosa and to bypass its first pass metabolim and also to improve the bioavailability of the drug using muco-adhesive polymers and PEG400 as plasticizer. Mucoadhesive polymer [1] such as Hydroxy Propyl Methyl Cellulose E5 (HPMC), Polyvinyl alcohol(PVA), Polyvinyl pyrollidine(PVP), Carboxy methyl cellulose(CMC), Carbopol 934 and Chitosan were used for the film. Prepared films were carried out for in vitro evaluation tests such as weight variation, film thickness, folding endurance, drug content, mucoadhesive strength [2] force of adhesion, bond strength, disintegration studies and dissolution studies. Attenuated total reflectance (ATR), Differential Scanning Calorimetry (DSC) and X-ray powder diffraction (XRD) analysis revealed no Interaction between drug and polymers. Results revealed that buccal film containing HPMC 5% (w/v) and PEG400 40% (w/w of dry polymer weight) shows maximum dissolution and comply all the characteristics of buccal films. Thus, this study suggests that “dissolving mucoadhesive buccal films” can act as a potential for buccal delivery of poorly water soluble hypolipidemic drug lovastatin.
Show more

12 Read more

Effect of multiple debonding sequences on shear bond strength of new stainless steel brackets

Effect of multiple debonding sequences on shear bond strength of new stainless steel brackets

Materials and Methods: Stainless steel twin brackets (0.022‑inch, American Orthodontics, Sheboygan, WI, USA) were bonded with light cure adhesive (Transbond XT, 3M Unitek, St. Paul, MN, USA) to 80 newly extracted human premolars after acid etching with 37% phosphoric acid (30 s). Brackets were debonded with a universal testing machine, and new brackets were bonded to teeth using the same adhesive and same manner. This process was repeated twice, and brackets were debonded within 24 h after bonding. The longitudinal changes of average SBS were assessed with the repeated measures ANOVA. Post‑hoc tests using the Bonferroni correction were also used to compare the average SBS at three debonding sequences.
Show more

6 Read more

The Effect of Titanium Tetrafluoride and Sodium Hypochlorite on the Shear Bond Strength of Methacrylate and Silorane Based Composite Resins: an In-Vitro Study

The Effect of Titanium Tetrafluoride and Sodium Hypochlorite on the Shear Bond Strength of Methacrylate and Silorane Based Composite Resins: an In-Vitro Study

Wettability is one of the most important physico- chemical surface properties and NaOCl is a non-specific proteolytic material which can remove organic materials and magnesium and carbonate ions. [23] Previous stud- ies have shown that after NaOCl treatment of dentin, an increase in wettability is expected because collagen removal produces a hydrophilic surface. The complete removal of organic components of the demineralized collagen matrix by NaOCl also increases the porosity of the intact dentin. The present study showed that the use of 5% NaOCl significantly decreased shear bond strength of single bond and silorane adhesive to dentin (p< 0.05). This is in accordance with the findings of the previous studies. [23-24, 28]
Show more

6 Read more

Shear bond strength of precoated orthodontic brackets: an <em>in vivo</em> study

Shear bond strength of precoated orthodontic brackets: an <em>in vivo</em> study

University. Twenty-two patients were selected from the general pool of patients waiting for orthodontic treatment at King Abdulaziz University in Jeddah, KSA. The selection criteria for the subjects included the following: willingness to participate in this study, the presence of intact upper denti- tion, the absence of caries, cracks, and dental restorations, and no missing teeth. A consent form was signed by each subject containing the full details of the study procedures. Patients were randomly assigned into one of two groups: one-hour debonding (OHDG) and two-week debonding (TWDG). In the OHDG, the one-hour debonding time was selected to be longer than the initial setting time registered for bracket bonding, which was estimated to be 15 minutes. 8
Show more

5 Read more

Show all 10000 documents...

Related subjects