452 Bond Strength of Orthodontic Cement at Different Time Intervals

Thursday, March 22, 2012: 3:30 p.m. - 4:45 p.m.
Presentation Type: Poster Session
I. FERRETO1, A.G. AGUILAR2, L. RODRIGUEZ2, and H. CACERES3, 1Univ. of Costa Rica, San Jose, Costa Rica, 2Restorative Sciences, Universidad de Costa Rica, San Jose, Costa Rica, 3Pediatrics and Orthodontics, Universidad de Costa Rica, San JosÚ, Costa Rica

Objectives: To determine bond strength to enamel of self-etch bonding system Transbond Plus SE Primer (TBSEP) applied at different time intervals after mixing its components, and before bonding the orthodontic brackets.

Methods: 30 recently extracted premolars, caries and restoration free, were placed over acrylic resin for support. The they were divided into three groups: CG: brackets were bonded over the enamel surface using Transbond Plus Self-etching Primer (3M ESPE, St Paul, MN) as recommended by manufacturer. Group EG1: waited 4 minutes after mixing the bonding agent components before bonding the brackets to enamel. Group EG2 waited 4 hours after mixing TBSEP components, before bonding the brackets to enamel. Specimens were stored in water at 37╝ C for 30 days before being tested in in shear at an unversal testing machine (Tinius Olsen H10KS) at a 0.1 cm/min crosshead speed. Data were recorded in MPa and analyzed using a one-way ANOVA calculated at a 0.05 significance level.

Results: Bond strength means and standard deviation (in parenthesis) are shown in table. No statistical difference were found among groups. Bond strength of EG2 was less than 1 MPa different from the control group. The hoghest bond strength was from group EG1 which used the bonding system to bond the brackets 4 minutes after it was mixed.

CG

EG1

EG2

Bond Strnegth, MPa

13.0(7.0)

14.8 (5.9)

12.0(3.5)

Conclusions: Waitting  up to 4 hours after mixing TBSEP components does not affects the bond strength of the orthodontic bracket to enamel.


Keywords: Adhesion, Dental materials, Enamel and Orthodontics