Bond strength of an adhesive polymerized under nitrogen.
OBJECTIVE
To evaluate the use of nitrogen, in conjunction with visible light polymerization, for improving composite-to-dentin bond strengths.


METHODS
Composite cylinders were bonded to dentin with Scotchbond Multi-Purpose. Immediate (Groups 1-4) and 24-hour (Groups 5-8) strengths were determined for the following two adhesive application and two polymerization techniques: Groups 1 & 5: gentle air thinning of adhesive and polymerization with conventional visible light curing (VLC) unit; Groups 2 and 6: aggressive air thinning of adhesive and conventional VLC; Groups 3 and 7: gentle air thinning of adhesive and polymerization in nitrogen environment with modified VLC unit; and Groups 4 and 8: aggressive air thinning of adhesive and polymerization in nitrogen environment with modified VLC unit.


RESULTS
The immediate bond strengths (MPa) were: Group 1: 15.1 +/- 1.8, Group 2: 6.1 +/- 2.1, Group 3: 17.8 +/- 3.1, Group 4: 15.8 +/- 2.0. The 24-hour strengths were: Group 5: 26.7 +/- 4.4, Group 6: 13.5 +/- 7.5, Group 7: 24.1 +/- 5.7, Group 8: 26.4 +/- 4.3. Visible light polymerization of a thinned layer of adhesive resin in a nitrogen environment produced significantly higher immediate and 24-hour bond strengths than when compared to visible light polymerization in ambient air.
Schvaneveldt
S L
SL
Creighton University, School of Dentistry, Omaha, NE 68178, USA.
Rozmajzl
W F
WF
Barkmeier
W W
WW
Latta
M A
MA
D000388:Air; D000704:Analysis of Variance; D003188:Composite Resins; D019245:Compressive Strength; D001840:Dental Bonding / Q000379:methods*; D017220:Dentin-Bonding Agents; D008027:Light; D008422:Materials Testing; D009584:Nitrogen; D011108:Polymers / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D012822:Silicon Dioxide; D013718:Tensile Strength; D015040:Zirconium
D003188:Composite Resins; D017220:Dentin-Bonding Agents; D011108:Polymers; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C083568:Z100 composite resin; D012822:Silicon Dioxide; D015040:Zirconium; D009584:Nitrogen