Er:YAG laser did not improve glass fibre post retention

Sandblasting and etching outperformed laser and silane

A glass fibre post is held in the canal by a combination of the cement and the preparation of its surface, and the procedures differ from practice to practice: sandblasting, chemical etching, silanisation, and more recently laser irradiation. The authors placed these procedures side by side under controlled conditions.

One hundred extracted maxillary central incisors were endodontically treated and prepared for glass fibre posts, then randomly divided into five groups of 20 samples: no treatment as control, aluminium oxide sandblasting, Er:YAG laser irradiation, hydrofluoric acid etching and silane application. All posts were cemented with a dual-cure composite cement, and pull-out strength was measured on a universal testing machine. The data were analysed with one-way ANOVA and the Tukey post-hoc test at an alpha of 0.05.

Hydrofluoric acid etching and aluminium oxide sandblasting produced significantly higher strength values than the control and than the laser and silane groups. The Er:YAG laser, under the parameters tested, did not improve post retention compared with an untreated surface. The team around B. Arıcan keeps the conclusion within the limits of the in vitro setup: conventional chemical and mechanical procedures showed more favourable bond behaviour.

Limitations

A pull-out test does not reproduce cyclic masticatory loading, moisture or temperature fluctuations in the mouth. The result applies to one set of laser parameters; a different energy, frequency or tip could give a different outcome. Funding was not stated in the abstract.

For your practice

• If you have an Er:YAG in the practice, in this setup there is no reason to spend a step on post preparation; the laser did not outperform even the untreated control.
• Only two procedures showed an effect, aluminium oxide sandblasting and hydrofluoric acid etching; before using them check the post manufacturer's recommendations for pressure and grit size.
• Silane on its own was not among the groups with higher values; it stayed in the same range of results as the laser and the untreated control.