Effect of instrument lubricant on the cohesive strength of a hybrid resin composite.
OBJECTIVE
The purpose of this study was to evaluate the effect of instrument lubricant on the cohesive strength of resin composite layers.


METHODS
Clear acrylic molds were filled with 3 increments of a hybrid resin composite using a metal instrument. The first increment (shade A2) was inserted to a height of 4 mm and light cured, followed by a 1-mm-high second increment (shade A1). The composite instrument was then wiped with 1 of 7 lubricants before insertion of a 1-mm-high third increment (shade A1): (1) isopropyl alcohol gauze, 70% v/v (AL); (2) acetone (AC); (3) Adper Single Bond Adhesive (SB); (4) One-Step Adhesive (OS); (5) D/E Bonding Resin (DE); (6) Scotchbond Multi-Purpose Adhesive (SP); (7) Tescera Sculpting Resin (TE). No lubricant was used in the control group (CT). A final 4-mm-high increment (shade A2) was inserted and light cured. The blocks were sectioned to obtain 48 sticks for each group. Sticks were fractured with an Instron machine. Statistics were computed using 1-way analysis of variance and Duncan's test.


RESULTS
Outcomes were as follows (mean +/- SD, MPa; same letters indicate significant differences at a confidence level of 95%): TE = 96.7A +/- 17.8; SP = 93.6AB +/- 9.6; DE = 93.4AB +/- 16.2; OS = 91.9AB +/- 19.5; AC = 90.1ABC +/- 12.2; SB = 89.9ABC +/- 14.5; AL = 88.8BC +/- 16.8; CT = 84.7C +/- 8.3.


CONCLUSIONS
Although the difference between Tescera Sculpting Resin and alcohol was statistically significant, Tescera Sculpting Resin is recommended only for indirect composite restorations. The lubricant used to reduce stickiness between the resin composite used for direct restorations and the composite instrument did not significantly reduce bond strengths.
Perdigăo
Jorge
J
University of Minnesota, Division of Operative Dentistry, Department of Restorative Sciences, 8-450 Moos Tower, 515 SE Delaware Street, Minneapolis, MN 55455, USA. perdi001@umn.edu
Gomes
George
G
D019840:2-Propanol / Q000737:chemistry; D000096:Acetone / Q000737:chemistry; D000180:Acrylic Resins / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry; D003762:Dental Instruments; D003793:Dental Restoration, Permanent / Q000379:methods*; D008153:Lubrication; D011140:Polyurethanes / Q000737:chemistry*; D013718:Tensile Strength
D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D003738:Dental Cements; D011140:Polyurethanes; D000096:Acetone; D019840:2-Propanol