Early and 24-hour bond strength and degree of conversion of etch-and-rinse and self-etch adhesives.
OBJECTIVE
To evaluate early and 24-hour microtensile bond strength (microTBS) and the degree of conversion (DC) of one representative adhesive system from each of the four current bonding approaches.


METHODS
40 human molars were sectioned occluso-gingivally into two halves. Resin composite was bonded incrementally to flat, mid-coronal dentin, using the adhesives Adper Scotchbond MP (MP); Adper Scotchbond 2 (SB); Clearfil SE Bond (SE); and Adper Prompt L-Pop (LP) according to the respective manufacturer's instructions (n = 10). One half was immediately sectioned into sticks and subjected to muTBS test. As the sectioning process took approximately 1 hour, the results were designated as 1-hour bond strengths. The other half was stored in distilled water at 37 degrees C for 24 hours before being sectioned and tested. The DC of these systems was measured using Fourier Transform-Raman spectroscopy in three periods: immediately, 1 and 24 hours after polymerization. Data were analyzed with ANOVA and Tukey's tests.


RESULTS
There were no significant differences between the 1-hour and 24-hour bond strengths (P > 0.05), or among the DC measured immediately, 1 hour and 24 hours after polymerization (P > 0.05). However, significant differences were observed among adhesives (P < 0.05). microTBS values obtained, in MPa (1 hour/24 hour), were: SB (48.6 + 1.3/48.4 + 3.5) = SE (51.9 + 4.7/53.3 +/- 2.9) > MP (35.3 +/- 10.9/38.6 + 6.7) > LP (25.5 + 1.1/26.0 + 1.5). The DC, in percentage (immediately/1 hour/24 hour), were: SE (81/82/87) > MP (79/77/81) > SB (60/63/65) > LP (39/37/42).
Sadek
Fernanda Tranchesi
FT
Department of Dental Materials, University of São Paulo, Av. Professor Lineu Prestes 2227, CEP: 05508-900 São Paulo, SP, Brazil. fernandasadek@gmail.com
Calheiros
Fernanda Calabró
FC
Cardoso
Paulo Eduardo Capel
PE
Kawano
Yoshio
Y
Tay
Franklin
F
Ferrari
Marco
M
D000134:Acid Etching, Dental / Q000379:methods*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
C438313:Clearfil SE Bond; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D011108:Polymers; C408584:Prompt L-Pop; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C121818:Tetric ceram; D014867:Water; C067788:scotchbond 2