The effect of storage conditions, contamination modes and cleaning procedures on the resin bond strength to lithium disilicate ceramic.
OBJECTIVE
The purpose of this in-vitro study was to evaluate the resin bond strength to pre-etched lithium disilicate ceramic using different cleaning methods after two contamination modes (saliva or saliva and silicone).


METHODS
Plexiglas tubes filled with composite resin (MultiCore Flow) were bonded to etched and silanized ceramic disks made of lithium disilicate ceramic (IPS e.max Press) using a luting resin (Multilink Automix). Either etched or unetched ceramic surfaces were contaminated with saliva or with saliva followed by a disclosing silicone. Groups of 16 specimens each were bonded after pretreatment using 4 surface cleaning agents (37% phosphoric acid, 5% hydrofluoric acid, 96% isopropanol, air polishing device with sodium bicarbonate) in different combinations. Before measuring tensile bond strength, specimens were stored for 3 or 150 days with thermocycling.


RESULTS
After 150 days of storage, etching of saliva-contaminated surfaces with 5% hydrofluoric acid and/or 37% phosphoric acid provided statistically significantly higher bond strengths (37.9 to 49.5 MPa) than the other cleaning methods (1.7 to 15.5 MPa). After saliva and silicone contamination, etching with 5% hydrofluoric acid provided statistically significantly higher bond strengths (44.5 to 50.3 MPa) than all other cleaning methods (0.3 to 13.5 MPa).


CONCLUSIONS
Ceramic cleaning methods after try-in procedures have a significant influence on the resin bond strength and are dependent on the type of contamination. Re-etching lithium disilicate ceramic with 5% hydrofluoric acid is most effective in removing contamination with saliva and/or a silicone disclosing medium.
Klosa
Karsten
K
Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian Albrechts University, Kiel, Germany. kklosa@proth.uni-kiel.de
Wolfart
Stefan
S
Lehmann
Frank
F
Wenz
Hans-Jürgen
HJ
Kern
Matthias
M
D019840:2-Propanol; D020906:Air Abrasion, Dental; D003188:Composite Resins; D003666:Decontamination / Q000379:methods*; D001840:Dental Bonding; D003776:Dental Porcelain; D003799:Dental Stress Analysis; D004356:Drug Storage; D006858:Hydrofluoric Acid; D010756:Phosphoric Acids; D019279:Resin Cements; D012463:Saliva; D012828:Silicones; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D014867:Water
D003188:Composite Resins; C074415:Fit-Checker; C508050:IPS e.max Press; D010756:Phosphoric Acids; D019279:Resin Cements; D012828:Silicones; C502351:multilink adhesive system; D014867:Water; D003776:Dental Porcelain; C030242:phosphoric acid; D019840:2-Propanol; D006858:Hydrofluoric Acid