Comparative Assessment of Color Stability in Four Commercial Clear Aligner Materials Exposed to Common Beverages: An...

Area of Science:

• Dental Materials Science
• Orthodontics
• Polymer Chemistry

Background:

• Clear aligner therapy (CAT) is a popular esthetic orthodontic alternative.
• Staining and color instability are significant clinical concerns for clear aligners.
• Limited comparative data exists on how different aligner polymers react to common staining beverages.

Purpose of the Study:

• To compare the color stability of four commercial clear aligner materials.
• To evaluate material response to immersion in tea, coffee, cola, and red wine over two weeks.

Main Methods:

• In vitro laboratory study with 40 aligner specimens (10 per brand).
• Specimens immersed in tea, coffee, cola, red wine, or distilled water.
• Color change (ΔE) measured using spectrophotometry at baseline and over 14 days.

Main Results:

• All materials had acceptable baseline color stability (ΔE < 3.3).
• Coffee and cola caused the most discoloration; ClearCorrect™ (PETG) and Illusion® (polyester blend) stained significantly within 24 hours.
• Invisalign® (polyurethane) showed moderate staining, while Graphy TC-85® (photocurable oligomer) was stable against acidic drinks but stained with tea.

Conclusions:

• Clear aligner color stability depends heavily on polymer chemistry and beverage type.
• PETG and multilayer polyester blends are highly susceptible to staining.
• Material-specific patient guidance is crucial for maintaining the esthetic longevity of clear aligners.