Saliva Effect on Bond Strength for a New Self-Etch Adhesive

Objectives:  This study investigated the effects of various human saliva contamination and decontamination protocols on the shear bond strengths (SBS) of a new two-bottle self-etch adhesive Adper^TM Scotchbond^TM SE (SBSE, 3M ESPE) on bovine cut enamel (E) and superficial dentin (D).

Methods:  A notched-edge shear method (Ultradent) was used to measure the SBS (composite: Filtek^TM Z250 A2, 3M ESPE) with n=10.  Bonded specimens were tested after 24 hr storage in water at 37C.  Various application protocols were used (see table), with the following abbreviations:

A = adhesive application per IFU

C = light cure per IFU

S = fresh human saliva application, 15 sec

D = air dry, 10 sec

R = rinse with water, 10 sec

Results: Mean (std dev) SBS in MPa and p-values (two-sample t-tests, p<0.05) are listed in the table.

Application Protocol	SBSE, E	SBSE, D
A-C [control]	36.3 (11.2)	39.2 (10.5)
S(wet)-A-C	34.7 (7.4) p=0.713	37.7 (12.1) p=0.758
S-D-A-C	35.6 (9.0) p=0.871	33.7 (9.9) p=0.245
A-C-S(wet)	38.7 (7.3) p=0.584	31.9 (7.7) p=0.096
A-C-S-D	37.4 (10.5) p=0.828	32.1 (8.0) p=0.105
A-C-S-R-D	32.4 (12.4) p=0.470	34.2 (9.2) p=0.271
A-C-S-R-D-A	39.6 (13.5) p=0.558	40.1 (9.7) p=0.847
A-S(wet)-C	7.0 (6.4) p=0.000	2.9 (6.7) p=0.000
A-S-D-C	27.6 (8.5) p=0.067	9.9 (6.1) p=0.000
A-S-R-D-C	20.4 (8.6) p=0.002	1.0 (2.0) p=0.000
A-S-R-D-A-C	37.8 (9.8) p=0.750	26.1 (9.5) p=0.009

Conclusion: 

SBSE maintained high SBS (32 to 40 MPa) statistically equivalent to the controls when saliva contamination occurred prior to applying adhesive or on the cured adhesive film.  Saliva applied to uncured adhesive resulted in statistically lower SBS than the controls, with a more pronounced effect on dentin.  However, if the saliva was rinsed off and the adhesive was reapplied, the SBS was increased to >20 MPa and was statistically equivalent to the control on E.