Influence of water concentration in an experimental self-etching primer on the bond strength to dentin.
OBJECTIVE
To investigate the influence of different water concentrations in the solvents of self-etching primers on microtensile bond strength (LTBS) of an experimental adhesive system.


METHODS
Five experimental self-etching primers with 0, 5, 10, 20 and 40 (wt%) water as solvent were formulated. An experimental adhesive resin (AD-50) was also synthesized to create one experimental self-etching adhesive system. Clearfil SE Bond (CSEB) was used as the commercial reference. Sixty bovine incisors were randomly separated into 6 groups. Buccal enamel was removed to expose the superficial coronal dentin; this surface was polished wet to create a standardized smear layer. After rinsing, water was removed, leaving the surface visibly dried. The dentin surfaces were etched with primer and air dried, adhesive resin was applied and photoactivated, then the composite resin restoration was placed. After storage for 24 h, the specimens were sectioned with a cooled diamond saw at low speed. Microtensile bond strength was measured and data were analyzed with one-way ANOVA/Tukey's test (alpha = 0.05).


RESULTS
ANOVA showed that primer composition was a significant factor for bond strength. There was no significant difference in bond strengths between the primers with a water concentration of 40% (53.9 +/- 12.7 MPa), 20% (51.1 +/- 11.5 MPa, and 10% (47.5 +/- 11.4 MPa), and CSEB (50.7 +/- 9.8 MPa). The groups with 5% (38.6 +/- 12.9 MPa) and 0% (31.5 +/- 7.5 MPa) water presented similar bond strengths amongst themselves but were statistically significantly lower than that of the other groups.


CONCLUSIONS
The water concentration in the primer solvent exercises a significant influence on the bond strength of this experimental self-etching adhesive system.
Lima
Giana da Silveira
Gda S
Department of Operative Dentistry, School of Dentistry, Federal University of Pelotas, RS, Brazil.
Ogliari
Fabrício Aulo
FA
da Silva
Eduardo Oliveira
EO
Ely
Caroline
C
Demarco
Flávio Fernando
FF
Carreño
Neftali Lenin V
NL
Petzhold
Cesar Liberato
CL
Piva
Evandro
E
D000818:Animals; D002417:Cattle; D002626:Chemistry, Pharmaceutical; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D045662:Dental Etching; D003764:Dental Materials / Q000737:chemistry; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000032:analysis / Q000737:chemistry*; D000431:Ethanol / Q000032:analysis / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000032:analysis / Q000737:chemistry; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry; D016369:Smear Layer; D012997:Solvents / Q000032:analysis / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000032:analysis / Q000737:chemistry*
C084111:Charisma composite resin; C438313:Clearfil SE Bond; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; D012997:Solvents; C114321:methacryloxyethyl dihydrogen phosphate; D014867:Water; D000431:Ethanol; C005044:hydroxyethyl methacrylate