Bond strength test of two resin adhesives to fiber post and the characteristics of adhesive interface between dentine and fiber post under confocal laser scanning microscopy

Liping CHEN; Linyan HUANG; Fuqiang ZHANG

ABSTRACT

BACKGROUND:

Resin adhesives include total-etching, self-etching and one-step adhesive. The studies concerning their adhesive properties remain different.

OBJECTIVE:

To compare the bonding strengths of fiber posts cemented to root canals with etch-and-rinse adhesives and self-etch adhesives, and to observe the physical interface bonding conformation using laser scanning confocal microscope so as to understand the retention of macro-and micro-morphology relationship.DESIGN, TIME AND

SETTING:

In vitro comparative observation was performed at the laboratories of Prosthodontics and Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University from March 2008 to March 2009.MATERIALS MATCHPOST fiber posts (Bisco, USA); etch-and-rinse adhesives (One-step, Bisco, USA) and self-etch adhesives (Panavia F adhesive system, Japan), fluorescein (Sigma, USA).

METHODS:

A total of 10 upper central incisor teeth, which had been freshly extracted for periodontal reasons, were selected,and the crown, 1 mm from the enamel-cementum junction, was cut. They were randomly divided into 2 groups with 5 specimens in each group. The fiber posts were bonded to root canals with One-Step or Panavia F which was tagged with rhodamine B.MAIN OUTCOME

MEASURES:

Each specimen was sectioned into two 2 mm-thick slices. A push-out test was made in a universal testing machine (EZ20), and confocal laser scanning microscopic (CLSM) analysis was performed to evaluate the primer penetration into dentin. The thickness of adhesive layer was measured by random software.

RESULTS:

The bonding strength of the group cemented with One-step was significantly greater than Panavia F (P < 0.05). The bonding strength of root crown was significantly greater than root apex (P < 0.05). One-step represented in CLSM image showed numerous and longer resin tags than Panavia F (P < 0.05).

CONCLUSION:

Etch-and-rinse adhesives (One-step) gained higher bonding strengths than self-etch adhesives (Panavia F).Resin binder to bond strength of fiber post and neck was greater than in the root apex.