The influence of ceramic surface treatments on the micro-shear bond strength of composite resin to IPS Empress 2.
OBJECTIVE
An increasing demand for esthetic restorations has resulted in the development of new ceramic systems, but fracture of veneering ceramics still remains the primary cause of failure. Porcelain repair frequently involves replacement with composite resin, but the bond strength between composite resin and all-ceramic coping materials has not been studied extensively. The purpose of this study was to evaluate the influence of different ceramic surface treatments on the micro-shear bond strength of composite resin to IPS Empress 2 coping material.


METHODS
Sixteen 7 x 7 x 1 mm(3) lithia disilicate-based core ceramic plates were fabricated using the lost wax technique. The plates were divided into eight groups, and eight different surface treatments were performed: (1) no treatment (NT); (2) airborne-particle abrasion with 50-mum alumina particles (Al); (3) acid etching with 9.6% hydrofluoric acid for 1 min (HF); (4) silane coating (S); (5) AlHF; (6) AlS; (7) HFS; and (8) AlHFS. Then, ten composite resin cylinders (0.8-mm diameter x 0.5-mm height) were light-polymerized onto the ceramic plates in each group. Each specimen was subjected to a shear load at a crosshead speed of 0.5 mm/min until fracture occurred. The fracture sites were examined with scanning electron microscopy (SEM) to determine the location of failure during debonding and to examine the surface treatment effects. One-way analysis of variance (ANOVA) and multiple comparison (Dunnet T3) tests were used for statistical analysis of data.


RESULTS
The mean micro-shear bond strength values (SD) in MPa were--NT: 4.10 (3.06), Al: 7.56 (4.11), HF: 14.04 (2.60), S: 14.58 (2.14), AlHF: 15.56 (3.36), AlS: 23.02 (4.17), HFS: 24.7 (4.43), AlHFS: 26.0 (3.71). ANOVA indicated the influence of surface treatment was significant (p < 0.0001). SEM analysis did not reveal entirely cohesive failure in any composite or ceramic.


CONCLUSIONS
The micro-shear bond strength of a composite resin to IPS Empress 2 was significantly different depending on the surface treatment method. Among the investigated methods, silane coating after airborne-particle abrasion and etching was the most effective surface treatment in terms of bond strength increase.
Panah
Faride Gerami
FG
Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Rezai
Sosan Mir Mohammad
SM
Ahmadian
Leila
L
D020906:Air Abrasion, Dental; D000704:Analysis of Variance; D003188:Composite Resins; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods; D003776:Dental Porcelain; D003799:Dental Stress Analysis; D019544:Equipment Failure Analysis; D018020:Lithium Compounds; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements; D033081:Shear Strength; D012821:Silanes; D013499:Surface Properties
D003188:Composite Resins; C118557:Empress 2; D018020:Lithium Compounds; D019279:Resin Cements; D012821:Silanes; C121818:Tetric ceram; C493120:lithia disilicate; D003776:Dental Porcelain