Statement of the problem: Despite the fact that adhesive luting is recommended for teeth rehabilitation with glass fiber posts, the most common failure of these restorations is debonding of the glass fiber posts.

Aim: To evaluate the effect of laser surface treatment of glass fiber posts on their bond strength to intra-radicular dentin at different root levels.

Materials and Methods: Twenty extracted single-rooted permanent human teeth were decoronated and endodontically treated. Post space of 10 mm length was prepared to receive glass fiber post. Teeth were randomly divided into 2 groups based on the surface treatment applied to the post surface as follows;

Group A (Control): post surface received conventional silane treatment,

Group B: Er:YAG laser was applied to the post surface followed by silane application. Prepared post spaces of all teeth were irrigated using standard irrigation protocol then dried and self-adhesive resin cement was used for posts cementation. For push-out bond strength evaluation, three slices for each sample were prepared, and the test was performed using a universal testing machine at a crosshead speed of 1 mm/min.

Results: Statistical analysis showed that group B provided significantly higher bond strength values compared to group A.

When different root sections were compared in each group: group A showed a significantly higher bond strength values in the middle and apical sections compared to cervical (p<0.05), while no significant difference was noticed between all sections in group B (p>0.05). In addition, the

Comparison between both groups in each section revealed that: group B showed significantly higher bond strength values in cervical and apical sections than group A. While in the middle section, group B recorded a non-significant increase in the bond strength compared to group A.

Conclusion: Er: YAG laser treatment for the post surface can be used as an alternative to conventional silane treatment to enhance its bonding to intra-radicular dentin.