Bond strength of an adhesive polymerized under nitrogen
Schvaneveldt, S.L.; Rozmajzl, W.F.; Barkmeier, W.W.; Latta, M.A.
American Journal of Dentistry 9(4): 157-160
1996
ISSN/ISBN: 0894-8275 PMID: 9002791 Document Number: 461793
To evaluate the use of nitrogen, in conjunction with visible light polymerization, for improving composite-to-dentin bond strengths. 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. 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.