Enamel etching by carbon dioxide laser. An in-vitro comparative evaluation

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Surface Science

Background:

• Dental composite restorations rely on effective enamel bonding for longevity.
• Surface preparation of enamel is critical for achieving optimal adhesion.
• Traditional methods like phosphoric acid etching are well-established, but novel techniques like laser etching are being explored.

Purpose of the Study:

• To compare the surface topography of dental enamel etched with carbon dioxide (CO2) laser versus 37% phosphoric acid.
• To evaluate and compare the shear bond strengths of dental composite bonded to enamel prepared by CO2 laser etching and phosphoric acid etching.

Main Methods:

• Scanning electron microscopy (SEM) was used to analyze the surface topography of etched enamel samples.
• Shear bond strength testing was performed on a Hounsfield Tensometer using 60 human premolars.
• A paired t-test was employed for statistical analysis of the shear bond strength data.

Main Results:

• SEM analysis revealed a poor etch pattern on enamel surfaces treated with CO2 laser.
• Composite bonded to CO2 laser-etched enamel exhibited significantly inferior shear bond strengths compared to acid-etched enamel.
• Statistical analysis confirmed a significant difference between the bond strengths achieved with laser and acid etching.

Conclusions:

• CO2 laser etching is less effective than 37% phosphoric acid in preparing dental enamel for composite bonding.
• Phosphoric acid etching provides superior surface topography and shear bond strength for dental composites.
• Current findings suggest that CO2 laser etching is not a suitable alternative to phosphoric acid for achieving reliable enamel-composite adhesion.