IADR Abstract Archives
Polymerization of Universal Adhesives: Effect of Enamel and Curing Lights
Objectives: Adhesives classified as “universal”, which can be applied both in etch-and-rinse or self-etch mode, have been recently introduced. Aim of this study was to investigate the polymerization of universal adhesives in presence of powdered enamel using two LED curing lights.
Methods: Adhesives tested were Adhese Universal (AD-U, Ivoclar Vivadent), Scotchbond Universal (SB-U, 3M ESPE), Peak Universal Bond (PK-U, Ultradent) and i-Bond Universal (iB-U, Heraeus Kulzer). Curing units tested were Demi-Ultra (Kerr) and Valo (Ultradent). Degree of conversion (DC) was determined using a FTIR-ATR equipment (Nicolet 6700-Thermo Scientific). Adhesives were placed on the FTIR diamond in their neat form or mixed with powdered enamel (adhesive/enamel ratio: 100μL/100mg) and polymerized for 20s using Demi-Ultra or Valo in standard power curing mode. Infrared spectra were obtained between 4000cm-1 and 500cm-1 (resolution: 6cm-1). DC was calculated using the ratio between the reaction C=C peak at 1635cm-1 and internal reference C=O peak at 1715cm-1.
Data were statistically analyzed within each adhesive group with two-way Anova (factors: enamel and curing light; p<0.05).
Results: Results are shown in Figure 1. PK-U did not show significant differences in DC in relation to the presence of enamel or the curing light used; iB-U showed a significant DC increase when mixed to enamel and when polymerized with Demi-Ultra (p<0.05); SB-U showed no significant differences when Valo was used, while a significant DC increase was found when mixed to enamel and polymerized with Demi-Ultra (p<0.05); AD-U showed a significant DC increase when mixed to enamel and polymerized with both Valo and Demi-Ultra (p<0.05).
Conclusions: The influence of enamel powder and curing unit type was material dependent. On average, however, DC was higher when adhesives were mixed with enamel powder, probably due to the neutralization of acidic monomers that may negatively affect the polymerization reaction.
Methods: Adhesives tested were Adhese Universal (AD-U, Ivoclar Vivadent), Scotchbond Universal (SB-U, 3M ESPE), Peak Universal Bond (PK-U, Ultradent) and i-Bond Universal (iB-U, Heraeus Kulzer). Curing units tested were Demi-Ultra (Kerr) and Valo (Ultradent). Degree of conversion (DC) was determined using a FTIR-ATR equipment (Nicolet 6700-Thermo Scientific). Adhesives were placed on the FTIR diamond in their neat form or mixed with powdered enamel (adhesive/enamel ratio: 100μL/100mg) and polymerized for 20s using Demi-Ultra or Valo in standard power curing mode. Infrared spectra were obtained between 4000cm-1 and 500cm-1 (resolution: 6cm-1). DC was calculated using the ratio between the reaction C=C peak at 1635cm-1 and internal reference C=O peak at 1715cm-1.
Data were statistically analyzed within each adhesive group with two-way Anova (factors: enamel and curing light; p<0.05).
Results: Results are shown in Figure 1. PK-U did not show significant differences in DC in relation to the presence of enamel or the curing light used; iB-U showed a significant DC increase when mixed to enamel and when polymerized with Demi-Ultra (p<0.05); SB-U showed no significant differences when Valo was used, while a significant DC increase was found when mixed to enamel and polymerized with Demi-Ultra (p<0.05); AD-U showed a significant DC increase when mixed to enamel and polymerized with both Valo and Demi-Ultra (p<0.05).
Conclusions: The influence of enamel powder and curing unit type was material dependent. On average, however, DC was higher when adhesives were mixed with enamel powder, probably due to the neutralization of acidic monomers that may negatively affect the polymerization reaction.
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