Orthodontic in vivo bond strength: comparison with in vitro results. Influence of force location in orthodontic shear bond strength testing. Effect of changing a test parameter on the shear bond strength of orthodontic brackets. Shear bond strength comparison between two orthodontic adhesives and self-ligating and conventional brackets. Shear bond strength of a new fluoride-releasing orthodontic adhesive. Shear bond strength of precoated orthodontic brackets: an in vivo study The influence of orthodontic bracket base design on shear bond strength. A 15-month evaluation of bond failures of orthodontic brackets bonded with direct versus indirect bonding technique: a clinical trial Bond strength comparison of moisture-insensitive primers. The influence of adding modified zirconium oxide-titanium dioxide nano-particles on mechanical properties of orthodontic adhesive: an in vitro study Comparison of bond strength of three adhesives: composite resin, hybrid GIC, and glass-filled GIC. A new one-step dental flowable composite for orthodontic use: an in vitro bond strength study. Effects on shear bond strength and the enamel surface with an enamel bonding agent. Influence of endodontic irrigants on bond strength of a self-etching adhesive. How and why of orthodontic bond failures: An in vivo study Comparison of bond strength between orthodontic brackets bonded with halogen and plasma arc curing lights: an in-vitro and in-vivo study. Comparison of bond strength between a conventional resin adhesive and a resin-modified glass ionomer adhesive: an in vitro and in vivo study.
The purpose of the present study was to test a new in vivo debonding device and compare in vivo bond strengths recorded by this device with in vitro bond strengths recorded by a universal testing machine such as the Instron . For the in vitro part of the study , 60 extracted premolar teeth were divided into 2 groups of 30 each . Both groups of 30 teeth had 3 M Unitek Victory Twin brackets , precoated with Transbond XT composite resin , bonded to them . Shear bond strength tests were carried out in vitro using the universal testing machine on one group of 30 teeth while the debonding device was used on the other group of 30 teeth . The mean shear bond strength of the group debonded using the universal machine was 11.02 MPa and that of the group debonded with the debonding device was 12.82 MPa . For the in vivo part of the study , 8 patients r and omly assigned to the research clinician from patients in The University of Alabama School of Dentistry , Department of Orthodontics , had a total of 60 premolar teeth bonded with 3 M Unitek Victory Twin brackets . Following comprehensive orthodontic treatment ( average time of 23 months ) , shear bond strength tests were carried out using the debonding device , which can measure debonding forces in vivo . The mean shear bond strength recorded in vivo was 5.47 MPa . Statistically significant differences were found between all 3 groups tested . The results appear to indicate that mean bond strengths recorded in vivo following comprehensive orthodontic treatment are significantly lower than bond strengths recorded in vitro OBJECTIVE The purpose of the present study was to analyze the influence of debonding force location in shear bond strength testing of orthodontic brackets in vitro . METHODS Ninety extracted permanent bovine m and ibular incisors were r and omly divided into 3 groups of 30 specimens each . Teeth were bonded with stainless steel orthodontic brackets . Enamel surfaces were etched with 37 % phosphoric acid for 30s and bonded with a composite adhesive .  Debonding force measurements were performed with a universal testing machine . Location of the debonding force was : bracket base ( group A ) , ligature groove ( group B ) , occlusal bracket wings ( group C ) . RESULTS Mean shear bond strength measurements were as follows : 22.70(4.23)MPa ( group A ) , 11.52(2.74)MPa ( group B ) , 9.44(2.96)MPa ( group C ) . Analysis of variance indicated that there were significant differences in shear bond strength . Post-hoc Tukey tests showed that bond strength measurements of group A were significantly different from those of groups B and C. The adhesive remnant index also showed significant differences and ranged from a mean of 1.53 in group A to a mean of 2.10 in group C. SIGNIFICANCE Debonding force location had a significant influence on shear bond strength measurements and bond failure pattern , indicating that this parameter needs to be taken into consideration for inter study comparison of in vitro results The purpose of this study was to determine the effect of changing the crosshead speed of the testing machine on the shear bond strength of orthodontic brackets to enamel while st and ardizing all the other variables . Forty freshly extracted human molars were bonded using the Transbond XT adhesive system ( 3 M Unitek , Monrovia , Calif ) . The teeth were r and omly divided into two groups . In group I , the shear bond strength was measured at a crosshead speed of 5.0 mm/min , and in group II the shear bond strength was measured at a crosshead speed of 0.5 mm/ min . Within half an hour from the initial bonding of each tooth , an occlusogingival load was applied to the bracket , producing a shear force at the bracket-tooth interface . This was accomplished by using the flattened end of a steel rod attached to the crosshead of a Universal Test Machine ( Zwick GmbH & Co , Ulm , Germany ) . The t-test results ( t = 2.71 ) indicated that there was a significant difference ( P = .014 ) in the shear bond strengths between the group tested at a crosshead speed of 5.0 mm/min and the group tested at a crosshead speed of 0.5 mm/min . The mean shear bond strengths for the two groups were 7.0 + /- 4.6 MPa and 12.2 + /- 4.0 MPa , respectively . These findings indicated that it is important to identify the parameters included in shear bond testing in order to enable meaningful comparisons of the performance of different material OBJECTIVE To evaluate and compare the shear bond strengths of two adhesives using two types of brackets : a conventional and a self-ligating bracket system . MATERIAL S AND METHODS Sixty extracted human premolars were collected . The premolars were r and omly divided into three groups of 20 teeth . All three groups were direct bonded . Groups 1 and 2 used light-cured adhesive and primer ( Transbond XT ) with a conventional ( Orthos ) and a self-ligating bracket ( Damon 2 ) , respectively . Group 3 used a light-cured primer ( Orthosolo ) and a light-cured adhesive ( Blūgloo ) with a self-ligating bracket ( Damon 2 ) . The specimens were stored in distilled water at 37 degrees C for 40 + /- 2 hours , after which they were debonded and inspected for Adhesive Remnant Index ( ARI ) scoring . RESULTS The mean shear bond strength was 15.2 MPa for group 1 , 23.2 MPa for group 2 , and 24.8 MPa for group 3 . A one-way analysis of variance and post hoc Tukey test showed significant differences in bond strength ( P < .001 ) between group 1 and groups 2 and 3 but no significant difference ( P > .05 ) between groups 2 and 3 . A Weibull analysis demonstrated that all three groups provided sufficient bond strength with over 90 % survival rate at normal masticatory and orthodontic force levels . A Kruskal-Wallis test showed no significant difference ( P > .05 ) in ARI scores among all three groups . CONCLUSIONS All three groups demonstrated clinical ly acceptable bond strength . The Damon 2 self-ligating bracket exhibited satisfactory in vitro bond strength with both adhesive systems used This study evaluated the shear bond strength of stainless steel brackets bonded to enamel with a new fluoride-releasing orthodontic adhesive system . A total of 140 extracted human bicuspids were r and omly divided into four groups . Group I ( Transbond XT ) was a control group in which enamel was etched with phosphoric acid . For the remaining groups , enamel was conditioned with a self-etching primer ( SEP ) : Group II ( Transbond Plus ) , Group III ( BeautyOrtho Bond ) , and Group IV ( BeautyOrtho Bond + Salivatect ) . Stainless steel brackets were bonded to all tooth sample s. After which , the sample s were stored , thermocycled , tested , and statistically analyzed . Besides bond strength evaluation , the adhesive remnant index ( ARI ) was also evaluated . The shear bond strengths of Groups II , III , and IV were significantly lower than Group I , and Group II was significantly greater than that of Group III . Concerning ARI scores , no significant differences were found between the groups . Further , no enamel fracture was observed during shear bond test with the new SEP . In conclusion , when enamel was conditioned with the new SEP , the mean values of shear bond strength yielded were lower than when it was etched with 37 % phosphoric acid . Nonetheless , these mean values were higher than the average suggested by Reynolds as optimum for clinical treatment Objective To evaluate the shear bond strength of precoated orthodontic brackets bonded with self-etching primer relative to that of noncoated conventionally-bonded brackets at two different time intervals . Methods Twenty-one subjects were selected for r and omized split-mouth bonding of two types of brackets to the maxillary arch . Half of the teeth had precoated brackets bonded using self-etching adhesive , and the other half had regular brackets bonded using Transbond XT adhesive . Nitinol wires were tied to the upper arch and were left until the time of debonding . The patients were r and omly divided into two groups : one debonded after one hour and the other debonded two weeks after the initial wire placement . The shear bond strength was directly recorded from the patients ’ mouths using an in vivo debonding device . Results There were no significant differences in shear bond strength between the precoated and conventional groups or within each group at different time intervals . There were significant differences between anterior and posterior teeth in both the precoated and conventional groups . Conclusion Pre-coated brackets bonded with self-etching adhesive have the same bonding strength as the conventionally bonded brackets Many bracket base design s and adhesive material s are in clinical use today . Bases have evolved from perforated metal bases to the present foil mesh bases , and treatments range from none , to spraying metal alloy onto the base , to the most common treatment of microetching . The purpose of this study was to determine the effect of orthodontic bracket base design on mean shear bond strength 1 hour or 24 hours after bonding . For each time group , 12 specimens of 6 types of metal brackets were bonded to bovine incisors with Transbond XT ( 3 M Unitek , Monrovia , Calif ) light-cured composite resin . Brackets were debonded 1 hour or 24 hours later , and the shear bond strength was recorded . Six debonded brackets of each type from each time group were selected at r and om and s and blasted . All the teeth were cleaned , and half were rebonded with used brackets , and half were rebonded with new brackets . Bond strength was measured again , 1 hour or 24 hours later . Representative specimens were inspected under the scanning electron microscope . Bracket base design significantly affected mean shear bond strength . Speed ( 60-gauge , microetched foil-mesh base ; Strite Industries , Cambridge , Ontario , Canada ) had the highest bond strength at 1 hour ; followed by Time ( machined , integral , microetched base with mechanical undercuts ; American Orthodontics , Sheboygan , Wis ) ; American Master Series ( 80-gauge foil-mesh base ; American Orthodontics ) ; Ovation Roth ( 80-gauge layered onto 150-gauge , microetched foil-mesh base ; GAC , Central Islip , NY ) ; Orthos Optimesh XRT ( 100-gauge microetched foil-mesh base ; Ormco , Orange , Calif ) ; and , finally , the nickel-free brackets ( injection molded , 100-gauge , microetched , foil-mesh base ; World Class Technology , McMinnville , Ore ) . The 24-hour results were similar except that Time had the highest mean shear bond strength ( ANOVA , P < .05 ) . Chairside s and blasting significantly affected the 1-hour , but not the 24-hour , mean shear bond strengths ( ANOVA , P < .05 ) . S and blasting appears to be an effective method of cleaning bracket bases before rebonding Background The purpose of this clinical longitudinal study was to investigate the effectiveness of indirect bonding technique evaluating the number of bond failures which occurred during treatment . Methods Fifty-two patients were selected and divided into two groups : group A ( 33 patients ) bonded with the direct technique and group B ( 19 patients ) bonded with the indirect technique . The number and date of bracket failure were recorded for over 15 months . Moreover , also the effect of crowding level on bracket failures was calculated . Statistical analysis was performed by means of t-test , Kaplan-Meier survival estimates and chi-squared test . Results No statistically significant differences were found in the total bond failure rate between direct and indirect techniques , also when comparing the upper and lower arches . The only significant difference was found comparing the posterior segment of the lower arches , in which a higher percentage of detachments were recorded in group B , bonded with the indirect technique . Moreover , no significant differences between direct and indirect bonding were found when evaluating crowding level . Conclusions Orthodontic practitioners can safely use the indirect bonding technique , even in patients with severe crowding , because it does not influence the adhesive quality and the bracket survival rate The objective of this in vitro bonding study was to evaluate the effectiveness of 2 moisture-insensitive primers , Assure ( Reliance Orthodontic Products , Itasca , Ill ) and MIP ( 3 M Unitek , Monrovia , Calif ) compared with a control hydrophobic primer , Transbond XT ( 3 M Unitek ) . Six groups of 40 premolars were acid etched and bonded using metal orthodontic brackets with the following in vitro protocol s : ( 1 ) Transbond XT primer and adhesive applied to a noncontaminated surface ; ( 2 ) Assure primer applied after saliva contamination ; ( 3 ) MIP primer applied after saliva contamination ; ( 4 ) Assure primer reapplied after saliva contamination ; ( 5 ) MIP reapplied after saliva contamination ; and ( 6 ) Assure adhesive applied after saliva contamination of the primer . All bonded specimens were stored in deionized water at 37 degrees C for 30 days and thermocycled for 24 hours before debonding . Brackets were debonded using a shear-peel load on a testing machine , bond strength was measured in megapascals , and bond failure was analyzed by using the adhesive remnant index . In vitro shear-peel bond strengths were acceptable for all groups , and the bond strengths for Assure and MIP were not significantly affected by saliva contamination . The mean shear-peel bond strength of the control ( 14.82 MPa ) was significantly higher ( P < .001 ) than the contaminated groups with the exception of MIP group 5 ( 14.02 MPa ) . The values of the Assure primer and adhesive were less than the MIP primer and its respective adhesive ; however , the hydrophilic Assure adhesive resin applied to a saliva-contaminated surface had acceptable bond strength . Bond failure analysis ( adhesive remnant index ) mainly showed adhesive bond failures . An increased frequency of enamel fractures at debond was noted , with the control group ( 1 ) and the MIP groups ( 3 and 5 ) having 22.5 % , 12.5 % , and 15 % , respectively . The Assure groups had no enamel fractures Background The purpose of this in-vitro study was to examine the effect of incorporating different concentrations of Zirconium oxide-Titanium dioxide ( ZrO2-TiO2 ) nanoparticles , which can have antibacterial properties , on the mechanical properties of an orthodontic adhesive . Methods ZrO2-TiO2 ( Zirconium oxide , HWNANO , Hongwu International Group Ltd , China ) -Titanium dioxide , Nanoshell , USA ) nanopowder were incorporated into orthodontic adhesive ( Transbond XT , 3 M Unitek , Monrovia , USA ) with different concentrations ( 0.5 % weight nonofiller and 1 % weight nanofiller ) . The size of nanoparticle was 70–80 nm for ZrO2 and less than 50 nm for TiO2 . For measuring the shear bond strength of the three groups of orthodontic adhesives [ Transbond ( control ) , Transbond mixed with 0.5 % weight ZrO2-TiO2 , and Transbond mixed with 1 % weight ZrO2-TiO2 ] , 30 freshly extracted human first premolars were used and bonded with stainless steel metal brackets ( Dentaurum ® , Discovery ® , Deutschl and ) , using the 3 orthodontic adhesives and 3 M Unitek ; Transbond TM Plus Self-Etching Primer ( 10 sample s in each group ) . The recorded values of compressive strength and tensile strength ( measured separately on 10 sample s of orthodontic adhesives ( add the 3 D size of sample , light cured for 40 s on both sides ) of each orthodontic adhesives ) , as well as the shear bond strength in Mega Pascal unit ( MPa ) were collected and exposed to one-way analysis of variance ( ANOVA ) and Tukey ’s post-hoc tests . Results orthodontic adhesive with 1 % weight ZrO2-TiO2 showed the highest mean compressive ( 73.42 ± 1.55 MPa , p : 0.003 , F : 12.74 ) , tensile strength ( 8.65 ± 0.74 MPa , p : 0.001 , F : 68.20 ) , and shear bond strength ( 20.05 ± 0.2 MPa , p : 0.001 , F : 0.17 ) . Conclusions Adding ZrO2-TiO2 nanoparticle to orthodontic adhesive increased compressive strength , tensile strength , and shear bond strength in vitro , but in vivo studies and r and omized clinical trials are needed to vali date the present findings The objective of this study was to compare 3  orthodontic adhesives  in the areas of shear-peel bond strength , location of adhesive failure , and extent of enamel cracking before bonding and after debonding of orthodontic brackets . The adhesives included a composite resin control ( Transbond XT ; 3M/Unitek , St Paul , Minn ) , a resin-modified glass ionomer cement ( Fuji Ortho LC ; GC America Corp , Alsip , Ill ) , and a polyacid-modified composite resin under dry and saliva-contaminated conditions ( Assure ; Reliance Orthodontic Products Inc , Itasca , Ill ) . Metal brackets were bonded to the buccal surfaces of 160 ( 4 groups of 40 ) human premolars . The bonded teeth were stored in deionized water at 37 degrees C for 30 days and thermocycled for 24 hours before debonding with a Universal Instron ( Instron Corp , Canton , Mass ) testing machine . The extent of cracking in the buccal surfaces was evaluated under 16x magnification before bonding and after debonding . Although the bond strength of the composite resin control ( 20.19 MPa ) was significantly greater ( P < .05 ) than that of the adhesives in the other groups , clinical ly acceptable shear-peel bond strengths were found for all adhesives ( Fuji Ortho LC = 13.57 MPa , Assure-dry = 10.74 MPa , Assure-wet = 10.99 MPa ) . The bond strength for the Assure adhesive was not significantly affected by saliva contamination . The sample of extracted premolars used in this study displayed a greater frequency of buccal surface enamel cracking ( 46.7 % ) than that reported in the literature for in vivo premolars ( 7.8%-10.2 % ) , which was possibly due to the extraction process . The frequency of enamel cracking in a subset of this sample ( n = 34 ) increased from 46.4 % at prebonding to 62.4 % at postdebonding as a result of the forces of debonding A new flowable composite , Denfil Flow , has shown an acceptable shear bond strength for bonding orthodontic brackets , when used with an intermediate , unfilled , low-viscosity resin . According to the manufacturer , it also shows a good viscosity for use with no preliminary adhesive . This could reduce the total time of bonding procedure while maintaining clinical ly useful bond strength . The aim of the current research was to assess this property . Eighty extracted human premolars were r and omly divided into four equal groups . Stainless steel brackets were bonded to etched enamel using ( 1 ) Denfil Flow , ( 2 ) a traditional flowable composite ( Dyract Flow ) , ( 3 ) Denfil Flow composite resin and an intermediate liquid resin , and ( 4 ) Transbond XT adhesive . Debonding was performed with a shearing force . The residual adhesive on the enamel surface was evaluated using the adhesive remnant index . The bond strength of Denfil Flow ( 34.8 MPa ) showed no significant difference with the other control groups and was clinical ly acceptable . Denfil Flow and Dyract Flow tended to display cohesive failure within the adhesive . Denfil Flow can be used without liquid resin to reduce the bonding procedure time while maintaining acceptable bond strength . Further studies are required to evaluate the enamel surface of the teeth after the same polishing procedure in the four groups INTRODUCTION The purpose of this study was to evaluate the shear bond strength of orthodontic brackets and the effect of an enamel bonding agent ( EBA ) on enamel surface after debonding . METHODS Seventy-five extracted maxillary premolars were collected and r and omly divided into 3 groups of 25 . The enamel cracks were surveyed with a stereomicroscope . In the first group , 1 layer of EBA was applied before the adhesive resin . In the second group , 2 layers of EBA were used ; in the third group , no EBA was used . Bonding was followed by incubation for 48 hours at 37 degrees C and thermocycling for 1000 cycles . Debonding was performed with a shear force . The surfaces of the teeth were evaluated , and the length , depth , direction of cracks , and adhesive remnants on the enamel surface were recorded . Data were analyzed by using analysis of variance and paired sample s t tests . RESULTS There were no significant differences between the shear bond strengths ( P = 0.341 ) of the 3 groups , or in the direction , length , and depth of the cracks before and after debonding ( P > 0.05 ) . There was a significant increase in the number of cracks after debonding in the 3 groups ( P < 0.05 ) . The evaluation of adhesive remaining on the surface of the teeth indicated that most bond failures occurred at the resin-bracket interface . CONCLUSIONS The use of EBA does not enhance bond strength or provide greater protection to the enamel surface during debonding The aim of this in vitro study was to evaluate the bond strength of a self-etching adhesive system to dentine irrigated with sodium hypochlorite ( NaOCl ) , chlorhexidine solution ( CX ) and ethylene diamine tetra acetic acid ( EDTA ) by microtensile testing . Sixty human third molars were sectioned 3 mm below the occlusal level and then r and omly divided into six groups : G1(control ) , without irrigant solution ; G2 , 1 % NaOCl ; G3 , 1 % NaOCl followed by the application of 17 % EDTA ; G4 , 2 % CX ; G5 , 2 % CX followed by the application of 17 % EDTA and G6 , 17 % EDTA . The specimens received the self-etching adhesive system were restored with composite resin , then sectioned and trimmed to obtain four hourglass-shaped slabs from each tooth . The specimens were su bmi tted to the microtensile test in a Universal Testing Machine at a crosshead speed of 0.5 mm min(-1 ) until fracture . The results were su bmi tted to statistical analysis by anova /Newman-Keuls . The means and st and ard deviations ( MPa ) were : G1 , 26.88 ( ±3.81 ) ; G2 , 19.08 ( ±3.89 ) ; G3 , 18.16 ( ±2.21 ) ; G4 , 18.14 ( ±4.32 ) ; G5 , 34.30 ( ±3.32 ) ; G6 , 13.61 ( ±1.21 ) . It was concluded that the application of 2 % CX followed by the application of 17 % EDTA result ed in increasing the bond strength of the self-etching adhesive system to dentine , when compared with the results obtained for the other tested groups Introduction : The bonding of orthodontic brackets and their failure rates by both direct and in-direct procedures are well-documented in orthodontic literature . Over the years different adhesive material s and various indirect bonding transfer procedures have been compared and evaluated for bond failure rates . The aim of our study is to highlight the use of a simple , inexpensive and ease of manipulation of a single thermo-plastic transfer tray and the use the of a single light cure adhesive to evaluate the bond failure rates in clinical situations . Material s and Methods : A total of 30 patients were r and omly divided into two groups ( Group A and Group B ) . A split-mouth study design was used , for , both the groups so that they were distributed equally with-out bias . After initial prophylaxis , both the procedures were done as per manufactures instructions . All patients were initially motivated and review ed for bond failures rates for 6 months . Results : Bond failure rates were assessed for over-all direct and indirect procedures , anterior and posterior arches , and for individual tooth . Z-test was used for statistically analyzing , the normal distribution of the sample in a spilt mouth study . The results of the two groups were compared and P value was calculated using Z-proportion test to assess the significance of the bond failure . Conclusion : Over-all bond failure was more for direct bonding . Anterior bracket failure was more in-direct bonding than indirect procedure , which showed more posterior bracket failures . In individual tooth bond failure , m and ibular incisor , and premolar brackets showed more failure , followed by maxillary premolars and canines INTRODUCTION This study assessed in-vitro shear bond strength and in-vivo survival rate of orthodontic brackets bonded with either a halogen  or a plasma arc light . METHODS Ninety extracted premolars were divided into 6 groups of 15 . Stainless steel brackets were bonded to the teeth by using either a halogen light with a 20-second curing time or a plasma arc light with a 2- , 6- , or 10-second curing time . Brackets were debonded either within 30 minutes of bonding or after thermocycling for 24 hours . Bond strengths were tested on a testing machine at a crosshead speed of 1 mm/minute . The bracket failure interface was measured with a modified adhesive remnant index score . Data were analyzed by using ANOVA and Tukey-Kramer multiple comparison tests . For the in-vivo study , a split-arch design was used to determine the bracket-failure rate and distribution in 25 patients . The patients were followed for a mean period of 1.1 years ( 386 days ) . Survival analysis was carried out to compare the failure rates of the 2 techniques . RESULTS No significant differences in bond strengths were found 30 minutes after bonding between the halogen light ( 13.6 + /- 3.8 MPa ) and the plasma arc light with 2- , 6- , or 10-second curing times ( 9.6 + /- 2.9 , 14.2 + /- 4.6 , 16.0 + /- 3.0 MPa , respectively ) . Similar bond strengths were also found between the halogen light with a 20-second ( 16.1 + /- 3.6 MPa ) curing time and plasma arc light with 6 seconds ( 18.2 + /- 4.6 MPa ) of curing time after 24 hours of thermocycling . For the in-vivo study , no significant difference was found in bracket failure rates between the 2 light sources ( 4.9 % in both groups ) . No significant differences were found between ARI scores for the halogen light and the plasma arc light at either 30 minutes or 24 hours after debonding . CONCLUSIONS These results indicate that the plasma arc light with a 6-second curing time can produce similar bond strength and bracket-failure rates as the halogen light that requires a longer curing time The objectives of this study were ( 1 ) to compare the in vivo survival rates of orthodontic brackets bonded with a resin-modified glass ionomer adhesive ( Fuji Ortho LC ; GC America , Alsip , Ill ) after conditioning with 10 % polyacrylic acid and a conventional resin adhesive ( Light Bond ; Reliance Orthodontic Products , Itasca , Ill ) bonded with 37 % phosphoric acid , ( 2 ) to compare the in vitro bond shear/peel bond strength between the 2 adhesives , ( 3 ) to determine the mode of bracket failure in the in vivo and in vitro tests according to the adhesive remnant index ( ARI ) , and ( 4 ) to compare the changes in surface morphology of enamel surface after etching or conditioning with 10 % polyacrylic acid , with scanning electron microscopy . In the in vitro study , 50 extracted premolars were r and omly divided into 4 groups : brackets bonded with Fuji Ortho LC or Light Bond adhesive that were debonded after either 30 minutes or 24 hours . Bond strengths were determined with a testing machine at a crosshead speed of 1 mm/min . Data were analyzed with analysis of variance and a paired Student t test . The in vivo study consisted of 398 teeth that were r and omly bonded with Fuji Ortho LC or Light Bond adhesive in 22 subjects with the split-mouth technique . Bracket survival rates and distribution were followed for 1.3 years . Data were analyzed with Kaplan-Meier product-limit estimates of survivorship function . The in vitro study results showed significant differences ( P < .05 ) among the adhesives and the debond times . Light Bond had significantly greater bond strengths than Fuji Ortho LC at 24 hours ( 18.46 + /- 2.95 MPa vs 9.56 + /- 1.85 MPa ) and 30 minutes ( 16.19 + /- 2.04 MPa vs 6.93 + /- 1.93 MPa ) . Mean ARI scores showed that Fuji Ortho LC had significantly greater incidences of enamel/adhesive failure than Light Bond adhesive ( 4.9 vs 4.1 ) . For the in vivo study , no significant differences in failure rate , sex , or location in dental arch or ARI ratings were found between the 2 adhesives . These results suggest that , compared with conventional resin , brackets bonded with resin-modified glass ionomer adhesive had significantly less shear bond strength in vitro . However , similar survival rates of the 2 material s studied after 1.3 years indicate that resin-reinforced glass ionomers can provide adequate bond strengths clinical ly . The weaker chemical bonding between the adhesive and the enamel might make it easier for clinicians to clean up adhesives on the enamel surface after debonding
Many studies on in-vitro orthodontic bond strength fail to report test conditions that could significantly affect their outcomes
INTRODUCTION The aims of this study were to systematic ally review the available literature regarding in-vitro orthodontic shear bond strength testing and to analyze the influence of test conditions on bond strength .