The influence of internal surface treatments on tensile bond strength for two ceramic systems.
BACKGROUND
The ceramic composition and surface microstructure of all-ceramic restorations are important components of an effective bonding substrate. Hydrofluoric acid and sandblasting are well-known procedures for surface treatment; however, surface treatment for high alumina-containing and lithium disilicate ceramics have not been fully investigated.


OBJECTIVE
This in vitro study evaluated the tensile bond strength of resin cement to two types of ceramic systems with different surface treatments.


METHODS
Thirty specimens of each ceramic system were made according to the manufacturer's instructions and embedded in polyester resin. Specimens of In-Ceram Alumina [I] and IPS Empress 2 [E] were distributed to three groups with differing surface treatments (n = 10): sandblasting with 50 microm aluminum oxide (APA); sandblasting with 110 microm aluminum oxide modified with silica particles (ROCATEC System-RS); a combination of sandblasting with APA and 10% hydrofluoric acid etching (HA) for two minutes on In-Ceram and for 20 seconds for IPS Empress 2. After the respective surface treatments, all the specimens were silanated, and Rely-X resin cement was injected onto the ceramic surface and light polymerized. The specimens were stored in distilled water at 37 degrees C for 24 hours and thermally cycled 1,100 times (5 degrees C/55 degrees C). The tensile bond strength test was performed in a universal testing machine at a 0.5 mm/minute crosshead speed.


RESULTS
The mean bond strength values (MPa) for IPS Empress 2 were 12.01 +/- 5.93 (EAPA), 10.34 +/- 1.77 (ERS) and 14.49 +/- 3.04 (EHA). The mean bond strength values for In-Ceram Alumina were 9.87 +/- 2.40 (IAPA) and 20.40 +/- 6.27 (IRS). All In-Ceram specimens treated with 10% hydrofluoric acid failed during thermal cycling.


CONCLUSIONS
The Rocatec system was the most effective surface treatment for In-Ceram Alumina ceramics; whereas, the combination of aluminum oxide sandblasting and hydrofluoric acid etching for 20 seconds worked more effectively for Empress 2 ceramics.
Kiyan
Vanessa Harumi
VH
Department of Restorative Dentistry, School of Dentistry, University Paulista (UNIP), São Paulo-SP, Brazil.
Saraceni
Cintia Helena Coury
CH
da Silveira
Bruno Lopes
BL
Aranha
Ana Cecília Corrêa
AC
Eduardo
Carlos da Paula
Cda P
D000134:Acid Etching, Dental; D000537:Aluminum Oxide / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D003461:Crystallography; D001840:Dental Bonding; D045662:Dental Etching; D003776:Dental Porcelain / Q000737:chemistry*; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry; D018020:Lithium Compounds / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors
C118557:Empress 2; C483026:In-Ceram Alumina; D018020:Lithium Compounds; C483701:Rely X Unicem; D019279:Resin Cements; D012821:Silanes; D003776:Dental Porcelain; D012822:Silicon Dioxide; D000537:Aluminum Oxide; D006858:Hydrofluoric Acid