Title: 1589 - Moisture Increases Nanoleakage at Orthodontic-primer/enamel Interface and Decreases Bond-strength


Mona Abbassy (Presenter)
King Abdulaziz University

Ahmed Bakry, King Abdulaziz University
Turki Bakhsh, King Abdulaziz University


Objectives: Orthodontic patients are developing white spot lesions and leakage around the orthodontic brackets due to difficulties in maintaining good oral hygiene. Nanoleakage between resin materials and tooth structure may be associated with degradation of bond strength and possible development of recurrent caries. Thus, the current study compared the sealing ability (nanoleakage test) and the bond strength of two orthodontic adhesive primers used for bonding orthodontic brackets under moist and dry enamel situation.

Methods: Transbond XT Primer (XT) and Moisture Insensitive Primer (MIP) (3M ESPE, USA) were applied respectively on the buccal surface of ninety human premolar teeth. They were randomly divided into three groups; XT, (MIP moist) and (MIP dry). In XT and (MIP dry) groups samples were etched with phosphoric acid and completely dried, while the buccal surfaces in (MIP moist) group were etched with phosphoric acid, then primed using MIP, keeping the enamel moist. Orthodontic brackets (MiniSprint®, Forestadent, Pforzheim, Germany.) were bonded to all groups with Transbond PLUS color change adhesive (3M Unitek, USA). Twenty specimens from each group were tested to record the debonding force of the brackets to tooth structure, while remaining ten specimens were cross-sectioned and stored in ammoniacal silver-nitrate solution to compare the nanaoleakage expression using scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS).

Results: One way ANOVA showed that Transbond XT and (MIP dry) groups recorded significantly higher bond strength values and less nanoleakage expression when compared with MIP moist (p>0.05).

Conclusions: Keeping the enamel surface dry decreases nanoleakage expression at enamel/primer interface and improves bond strength of MIP to enamel.

This abstract is based on research that was funded entirely or partially by an outside source:
Deanship of scientific research, King Abdulaziz university, Saudi Arabia

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: Deanship of Scientific research, King Abdulaziz University, Saudi Arabia.