[Effect of different orthodontic interproximal reduction methods on the enamel]

Area of Science:

• Dental materials science
• Biomaterials engineering
• Oral health research

Background:

• Interproximal enamel reduction (IER) is a common orthodontic procedure.
• Evaluating the effectiveness and surface integrity after different IER methods is crucial for clinical application.
• Understanding the long-term effects of IER on enamel surface properties is essential.

Purpose of the Study:

• To determine the most suitable interproximal enamel reduction (IER) method for clinical use.
• To compare the effects of mechanical and chemo-mechanical IER techniques on enamel surface microhardness and morphology.
• To assess enamel surface changes after in vitro pH cycling following IER.

Main Methods:

• Fifty human premolars were sectioned and divided into five groups: stripping strip, stripping disk, stripping strip with chemical polish, stripping disk with chemical polish, and a control.
• Samples underwent 30 days of in vitro pH cycling.
• Enamel surface microhardness was measured, and surface morphology was examined using scanning electron microscopy (SEM).

Main Results:

• Significant differences in enamel microhardness and surface morphology were observed between the groups (ANOVA, P<0.05).
• Chemo-mechanical IER groups (using orthophosphoric acid and polishing system) showed superior surface quality compared to mechanical methods alone.
• No significant difference was found between stripping strip and stripping disk methods when used alone or with chemical polishing.

Conclusions:

• Mechanical IER methods (stripping strip and disk) show no significant difference in effectiveness.
• Combining mechanical reduction with chemical polishing (35% orthophosphoric acid and polishing system) yields better enamel surface results.
• Scratches on the enamel surface resulting from IER are persistent and show limited repair even after in vitro remineralization.