Effect of cyanoacrylate-based β-TCP adhesive on pullout strength of orthodontic mini-screw

Abstract

In this study, the effect of cyanoacrylate-based β-tricalcium phosphate (β-TCP) on pullout strength of orthodontic mini-screw was evaluated. New cements were prepared by mixing Histoacryl® (n-butyl cyanoacrylate) and acid-treated β-tricalcium phosphate. The ratios of β-TCP to Histoacryl® were 0, 0.5, 1.0, and 2.0. Artificial bone blocks were used as a substrate for the miniscrew implantation. The test groups were divided into three groups (one solid bone block [group 1] and a bone block with a 0.9 mm hole [group 2], and a bone block with a 2.5 mm hole [group 3]). And each group was divided into subgroups according to cement usage and non-usage. The used artificial bone density was 0.64g/cm2. Pullout strengths were determined using a universal testing machine. Statistical analysis was performed using the SPSS 9.0 for Windows program. Paired samples t-tests and ANOVA were used with p<0.05. The maximum pullout strengths were 295.9 ± 3.8 N for group 1, 261.1±15.0 N for group 2, and 273.2±20.0 N for group 3. In group 1 and 2, the pullout strength in the subgroup using cement was higher than that of the subgroup of not using cement (p<0.05). In group 3, the pullout strength in the subgroups using cyanoacrylate-based β- TCP cement was higher than that of the subgroup using conventional glass ionomer cement (GC Fuji-I, GC Co., Tokyo, Japan) (p<0.05). These results indicate that our β-TCP/Histoacryl® cements have the potential to enhance pullout strength of the orthodontic mini-screw.