Fluoride-containing adhesive: durability on dentin bonding.
OBJECTIVE
To evaluate (1) the influence of fluoride-containing adhesive on microtensile bond strength (microTBS) and (2) in vitro secondary caries inhibition at the resin-dentin interface after 24 h and 3 months water-storage and (3) the degree of conversion of different adhesives after 24h 1 month.


METHODS
Flat surfaces of human teeth were ground and randomly assigned to six groups: (SBMP-24) Scotchbond Multi-Purpose control [SBMP], 24 h; (SE-24) SBMP etch and primer+Clearfil SE Bond adhesive [SE], 24h; (PB-24) SBMP etch and primer+Clearfil Protect Bond adhesive [PB], 24h; (SBMP-3) SBMP, 3 months; (SE-3) SBMP+SE, 3 months; and (PB-3) SBMP+PB, 3 months. To evaluate the effect of the adhesive resin alone, all teeth were etched with 35% phosphoric acid and primed with SBMP primer prior to applying the adhesive resin. Bonded assemblies were prepared for microTBS and stored in distilled water at 37 degrees C for 24h and 3 months. Sections of restored teeth of each group were exposed to an acid challenge. The specimens were sectioned, polished, and then observed with polarized light microscopy (PLM). Also, the degree of conversion (DC) of the adhesives was measured using Fourier Transform-Infrared spectroscopy (FTIR) at 24 h and 1 month, after polymerization.


RESULTS
microTBS values obtained in MPa (24h/3m) were: (MP) 61.5+/-10.5/52.9+/-8.9, (SE) 55.5+/-11.8/55.6+/-13, and (PB) 50.3+/-9.9/61.0+/-13.6. For interface analysis by PLM, an inhibition zone (IZ) adjacent to the hybrid layer was created only when the fluoride-containing adhesive (PB) was used. The DC in percentage (24 h, 1 month) were: (MP) 60.5+/-2.8/61.3+/-0.6, (SE) 69.6+/-1.3/70.7+/-0.05, and (PB) 53.1+/-0.4/58.3+/-1.6.


CONCLUSIONS
The fluoride-containing adhesive demonstrated significant increase of bond strength values after water-storage. This material was also able to create an acid inhibition zone in dentin. There was a significant increase of degree of conversion after 1 month only for PB.
Shinohara
Mirela S
MS
Dental Materials Division, Department of Restorative Dentistry, Piracicaba School of Dentistry, State University of Campinas, Piracicaba, SP, Brazil. miodonto@hotmail.com
De Goes
Mario F
MF
Schneider
Luis Felipe J
LF
Ferracane
Jack L
JL
Pereira
Patricia N R
PN
Di Hipólito
Vinícius
V
Nikaido
Toru
T
D000134:Acid Etching, Dental; D000143:Acids / Q000737:chemistry; D002326:Cariogenic Agents / Q000737:chemistry; D002327:Cariostatic Agents / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D003731:Dental Caries / Q000473:pathology; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008859:Microscopy, Polarization; D063065:Organophosphonates / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000143:Acids; D002326:Cariogenic Agents; D002327:Cariostatic Agents; C503075:Clearfil Protect Bond; C438313:Clearfil SE Bond; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; D063065:Organophosphonates; D011108:Polymers; C409388:Protect Liner F; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C454540:Scotchbond etchant; D012821:Silanes; D014867:Water; C061501:Scotchprime; D005459:Fluorides