• Supaporn Durongwong D.D.S.
• Siriporn Arunpraditkul D.D.S., M.Sc.
• Issarawan Boonsiri D.D.S., Cert. in Fixed Prosth.

Objective This study was to evaluate the push out bond strength of fiber reinforced composite (FRC)
post luted with self adhesive resin cement in different root canal surface treatments.

Materials and methods Forty single-rooted mandibular premolars were randomly divided in four
groups (n=10). After decoronation and endodontic treatment, post spaces were prepared for fiber
reinforced composite post, Fibrekleer^® no.3. Root canal surface was treated as follows, group 1: no
surface treatment, group 2: etching with 37% phosphoric acid for 5 seconds, group 3: irrigation with
17% EDTA for 1 minute, and group 4: irrigation with 17% EDTA for 1 minute followed by 2.5%
NaOCl for 15 seconds. All roots were restored with posts and luted with self adhesive resin cement,
RelyX^TM Unicem (RelyX^TM Unicem, 3M ESPE, USA). Each root was sectioned to 6 slices, each
1 ± 0.05 mm thickness. A push out test was performed by a universal testing machine (Instron^®), at a
crosshead speed of 0.5 mm/min. Data were analyzed with two-way ANOVA and Tukey multiple
comparison test at significant differences (p < 0.05). Fracture modes were evaluated in all specimens
with stereomicroscope.

Results Push out bond strength in group 2 was statistically significant highest. Bond strength of group
3 was significantly higher than those of group 1 and 4. Whereas, there was no significant difference
between group 1 and 4 (p > 0.05). The push out bond strength were not affected by root regions in all
groups (p > 0.05).

Conclusion Root canal surface treatment with 37% phosphoric acid for 5 seconds or 17% EDTA for
1 minute increased the push out bond strength of self adhesive resin cement.

(CU Dent J. 2012;35:167-78)