Bond strength of composite resin to glass ceramic after saliva contamination.
OBJECTIVE
Purpose of this study was to investigate the effect of cleaning methods of glass ceramic specimens contaminated with saliva on tensile bond strength (TBS) to composite resin. Additionally, effect of water storage on bond strength was evaluated.


METHODS
Glass ceramic discs (IPS Empress, Ivoclar-Vivadent, FL) distributed among five groups (n = 28) were etched with hydrofluoric acid, silanized, contaminated with human saliva, and in group W rinsed with water, group WS additionally silanized, group E rinsed with water and cleaned with ethanol, and group ES additionally silanized. Group C served as a control without contamination. Plastic screws were bonded to the glass ceramic discs using Variolink II (Ivoclar-Vivadent). TBS was measured after 24 h and after 150 days of storage. Failure modes were examined. ANOVA was applied to explore group effect on TBS. Pair-wise comparisons were calculated.


RESULTS
The mean TBS [in megapascals] were for W 46 ± 14, WS 55 ± 8, E 48 ± 11, ES 52 ± 10, and C 50 ± 8 after 24 h, and W 39 ± 11, WS 53 ± 9, E 48 ± 8, ES 48 ± 11, and C 50 ± 8 after 150 days. After 150 days specimens of group W showed significantly lower TBS compared to group C (p = 0.05). Additional silanization in group WS led to a significant increase of TBS compared to specimens of group W (p = 0.003). Adhesive fractures were observed only in specimens without second application of silane.


CONCLUSIONS
The cleaning of the contaminated glass ceramic surface by rinsing only did not result in a durable bond.


CONCLUSIONS
Pre-silanized glass ceramic restorations need to be rinsed and treated with a fresh layer of silane after saliva contamination.
Dental School and Hospital, Department of Operative Dentistry and Periodontology, Albert-Ludwigs-University Freiburg, Hugstetterstrasse 55, 79106, Freiburg, Germany.
Frank
F
Nikolaus
Martin
M
Wolkewitz
Petra
P
Hahn
D000538:Aluminum Silicates; D000704:Analysis of Variance; D003666:Decontamination / Q000379:methods*; D001840:Dental Bonding; D003776:Dental Porcelain; D003799:Dental Stress Analysis; D000431:Ethanol; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D019279:Resin Cements; D012463:Saliva; D012821:Silanes; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D014867:Water
D000538:Aluminum Silicates; C075815:IPS-Empress ceramic; D019279:Resin Cements; D012821:Silanes; D014867:Water; D003776:Dental Porcelain; C103502:Variolink; D000431:Ethanol