Comparison of the bonding strengths of second- and third-generation light-emitting diode light-curing units

Abstract

ObjectiveWith the introduction of third-generation light-emitting diodes (LEDs) in dental practice, it is necessary to compare their bracket-bonding effects, safety, and efficacy with those of the second-generation units.MethodsIn this study, 80 extracted human premolars were randomly divided into eight groups of 10 samples each. Metal or polycrystalline ceramic brackets were bonded on the teeth using second- or third-generation LED light-curing units (LCUs), according to the manufacturers’ instructions. The shear bond strengths were measured using the universal testing machine, and the adhesive remnant index (ARI) was scored by assessing the residual resin on the surfaces of debonded teeth using a scanning electron microscope. In addition, curing times were also measured.ResultsThe shear bond strengths in all experimental groups were higher than the acceptable clinical shear bond strengths, regardless of the curing unit used. In both LED LCU groups, all ceramic bracket groups showed significantly higher shear bond strengths than did the metal bracket groups except the plasma emulation group which showed no significant difference. When comparing units within the same bracket type, no differences in shear bond strength were observed between the second- and third-generation unit groups. Additionally, no significant differences were observed among the groups for the ARI.ConclusionsThe bracket-bonding effects and ARIs of second- and third-generation LED LCUs showed few differences, and most were without statistical significance; however, the curing time was shorter for the second-generation unit.

Effect of different bonding protocols on degree of monomer conversion and bond strength between orthodontic brackets and enamel

“…According to the literature, 29 values higher than 13 MPa might increase the risk of enamel rupture, since the cohesive forces of enamel can be exceeded. Only the group polymerized by Valo Cordless for 3 seconds approached the clinically acceptable 15 range of 6 to 8 MPa, as opposed to the results presented by Oz et al 4 and Lee et al, 30 who reported averages of 11.43 MPa and 16 MPa, respectively for the Radii-Call and Valo Cordless. The difference is probably because the two studies evaluated adhesive resistance after a very short storage period (24 hours).…”

“…The difference is probably because the two studies evaluated adhesive resistance after a very short storage period (24 hours). In addition, Lee et al 30 used two exposures of 3 seconds each, whereas this study used a single exposure of 3 seconds.…”

Light Activation and Thermocycling Methods on the Shear Bond Strength of Brackets Bonded to Porcelain Surfaces

“…The first hypothesis that light sources would not change the shear strength of metal brackets bonded to porcelain surfaces was confirmed, since no statistically significant differences were found between the different light activation sources at different time periods and power levels. This finding is in line with those described in the literature, which has not shown significant differences in light activation sources and time regarding the bonding of brackets to different surfaces, such as bovine enamel, human enamel, and porcelain, even though the light activation sources are not the same (4,6,7,12,18,19). Oz et al (10) assessed LED sources using similar light activation time to the one used herein and they did not find statistically significant differences, but they observed shear strength in metal brackets bonded to extracted human premolars and not in ceramic surfaces.…”

Comparative study of three composite materials in bonding attachments for clear aligners

“…Therefore, it is particularly important to select a kind of attachment material with good bonding performance, which directly affects the efficiency of tooth movements and treatment outcomes. Light‐cured composite resins represent the most popular choice in restorative dentistry due to improved aesthetics and adhesion to tooth structure 4 . Therefore, light‐cured composite resins are often used as attachment materials clinically.…”