• Journal of the korean academy of Pediatric Dentistry
• /
• v.36 no.3
• /
• pp.427-432
• /
• 2009

The aim of this study was to compare the shear-peel strength and the fracture site of 5 commercially available orthodontic band cements. One hundred molar bands were cemented to extracted human 3rd molars. The specimens were prepared in accordance with the manufacturer's instructions for each cement. After storage in a humidor at $37^{\circ}C$ for 24 hours, the shear debonding force was assessed for each specimen using an universal testing machine with crosshead speed of 2 mm/minute. Maximal failure stress was converted to mean shear-peel strength, MPa. The predominant site of band failure was recorded visually for all specimens as either at the band/cement or cement/enamel interface. Mean shear-peel strength of Ormco was the highest(2.44${\pm}$0.57), followed by Fuji $Ortho^{TM}$(2.24${\pm}$0.50), $Ketac-Cem^{TM}$(2.10${\pm}$0.57), 3M $Unitek^{TM}$(1.82${\pm}$0.43), $Band-Lok^{TM}$(1.73${\pm}$0.28). There were statistically significant differences between Ormco and $Band-Lok^{TM}$, Ormco and 3M $Unitek^{TM}$, and Fuji $Ortho^{TM}$ and $Band-Lok^{TM}$(p<0.05). The predominant site of bonding failure for bands cemented with the Ormco was at the band/cement interface, whereas bands cemented with Ultra $Band-Lok^{TM}$ failed predominantly at the enamel/cement interface. There was no significant difference among the other cements(Fuji $Ortho^{TM}$, 3M $Unitek^{TM}$, $Ketac-Cem^{TM}$).

• Journal of the korean academy of Pediatric Dentistry
• /
• v.34 no.3
• /
• pp.420-429
• /
• 2007

The purpose of this study was to compare the micro ensile bond strength to bovine dentin of several adhesives (SM, Scotch $Bond^{TM}$ Multipurpose; SB, $Adper^{TM}$ Single Bond 2; SE, $Clearfil^{(R)}$ SE Bond; AQ, AQ $Bond^{TM}$; TS, $Clearfil^{(R)}$ tri-S Bond). Except SM and SB, they have a simplified one- or two-step application protocols in compare with the dentin adhesives conventional three-step protocols. For the microtensile bond strength test, the labial surfaces of bovine incisors were used. Following exposure of dentin layer, according to their manufacturer's directions, each dentin adhesives were applied and composite resin blocks were constructed. The teeth were sectioned for specimen and tested microtensile bond strength. Also observed the fracture mode of interface. The obtained results were as follows : 1. The microtensile bond strength values ranged from 51.34 to 24.04 MPa on dentin(in decreasing order, SE, SM, SB, AQ and TS). 2. The highest microtensile bond strength was by SE and SM on bovine dentin, and the lowest by AQ and TS. 3. SM, SB and SE showed cohesive failures and adhesive failure but AQ, TS presented almost adhesive failures. In summary, microtensile bond strengths of single-step adhesives (AQ and TS) on bovine dentin were significantly lower than those of multi-step adhesives (SM, SB and SE) (p<0.05).