How wet should dentin be? Comparison of methods to remove excess water during moist bonding.
OBJECTIVE
The aim of this study was to evaluate the shear bond strength of two adhesive systems when applied on dentin surfaces with different degrees of wetness.


METHODS
Two-hundred ten dentin specimens were used. After conditioning with 35% phosphoric acid gel and washing, seven methods of drying dentin were used: 30 s air spray (groups 1 and 2), 5 s air spray (groups 3 and 4), dry cotton pellets (groups 7 and 8), wet cotton pellets (groups 9 and 10), microbrush (groups 11 and 12), absorbent paper (groups 13 and 14). The last group was not dried; the dentin surfaces were left overwet (groups 5 and 6). Prime & Bond 2.1 adhesive was applied on the odd-numbered groups and Scotchbond Multi Purpose on the even-numbered groups. Z100 composite cylinders were bonded to the adhesive and the specimens were subjected to a shear bond test.


RESULTS
The Least-Squares Means test was used to compare the following results, where different letters indicate significantly different mean values: Group 9 (G9) = 23.2 MPa (a), G3 = 21.3 MPa (ab), G2 = 19.5 MPa (bc), G10 = 18.6 MPa (bc), G14 = 16.3 MPa (cd), G8 = 16.1 MPa (cd), G4 = 14.6 MPa (de), G13 = 14.0 MPa (de), G11 = 13.9 MPa (de), G7 = 13.5 MPa (de), G12 = 12.1 MPa (e), G1 = 8.2 MPa (f), G5 = 2.7 MPa (g), G6 = 2.4 MPa (g).


CONCLUSIONS
The adhesion values were affected both by the degree of dentin wetness and by the adhesive systems.
Pereira
G D
GD
Gama Filho University, School of Dentistry, Rio de Janeiro, Brazil. giseledamiana@yahoo.com
Paulillo
L A
LA
De Goes
M F
MF
Dias
C T
CT
D000096:Acetone; D000704:Analysis of Variance; D003188:Composite Resins; D001840:Dental Bonding / Q000379:methods*; D003804:Dentin / Q000737:chemistry*; D017220:Dentin-Bonding Agents; D003890:Desiccation / Q000379:methods*; D006801:Humans; D016018:Least-Squares Analysis; D008422:Materials Testing; D008964:Molar, Third; D011109:Polymethacrylic Acids; D019279:Resin Cements; D012822:Silicon Dioxide; D013718:Tensile Strength; D014867:Water; D015040:Zirconium
D003188:Composite Resins; D017220:Dentin-Bonding Agents; D011109:Polymethacrylic Acids; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C083568:Z100 composite resin; C444444:prime and bond 2.1; D014867:Water; D000096:Acetone; D012822:Silicon Dioxide; D015040:Zirconium