Tetrahydrofuran as alternative solvent in dental adhesive systems.
OBJECTIVE
To evaluate the influence of tetrahydrofuran (THF) on the resin-to-dentin microtensile bond strength (microTBS) after water storage, for 24h and 6 months, and to compare its behavior with that of traditional solvents.


METHODS
Seven versions of monomer/solvent mixtures (primers) were prepared using the following solvent and water combinations: (1) THF, (2) acetone, (3) ethanol, (4) water, (5) THF/water, (6) acetone/water and (7) ethanol/water. An experimental adhesive resin was also synthesized to compare adhesive systems with the different primers. Forty-two bovine incisors, randomly separated into seven groups, had their superficial coronal dentin exposed. After acid-etching and rinsing, the excess water was removed from the surface with absorbent paper. Each experimental primer was applied with agitation (30s) followed by a mild air stream (10s). The experimental adhesive resin was applied and light-activated (20s). Resin composite restorations were constructed incrementally. Restored teeth were stored in distilled water at 37 degrees C (24h) and sectioned to obtain sticks with an area of 0.5mm(2). Half the specimens were subjected to the microTBS test immediately after being cut and the other half were tested after 6 months of water storage. Data (MPa) were analyzed by two-way ANOVA (solvent type and storage time as factors) and Tukey-Kramer's test at alpha=0.05.


RESULTS
Factors and interaction showed a statistical effect. After 6 months storage, acetone groups and primers containing THF showed similar microTBS to initial means.


CONCLUSIONS
THF seems to be a promising solvent for use in dental adhesive systems, maintaining bond strength on dentin substrate after storage.
Fontes
Silvia T
ST
School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil. fontesst@gmail.com
Ogliari
Fabrício A
FA
Lima
Giana S
GS
Bueno
Márcia
M
Schneider
Luis Felipe J
LF
Piva
Evandro
E
D000096:Acetone / Q000737:chemistry; D000134:Acid Etching, Dental; D000268:Adhesiveness; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D005663:Furans / Q000737:chemistry*; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
C084111:Charisma composite resin; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D005663:Furans; D008689:Methacrylates; D010756:Phosphoric Acids; D011109:Polymethacrylic Acids; D019279:Resin Cements; D012997:Solvents; D014867:Water; D000096:Acetone; C020946:triethylene glycol dimethacrylate; D000431:Ethanol; C018674:tetrahydrofuran; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate; C030242:phosphoric acid