Color changes of nanocomposites used for clear aligner attachments: an in vitro study

Area of Science:

• Dental Materials Science
• Orthodontics
• Esthetic Dentistry

Background:

• Clear aligner attachments are crucial for effective orthodontic treatment.
• Nanocomposite materials are increasingly used for dental restorations.
• Understanding the color stability of these materials is vital for patient satisfaction.

Purpose of the Study:

• To compare the color changes of two distinct nanocomposites (packable and flowable) used in two different clear aligner attachment designs.
• To evaluate the impact of staining on the color stability of these nanocomposites.

Main Methods:

• 120 human premolars were used to create dental models with two attachment designs: conventional (CA) and optimized multiplane (OA).
• Packable composite (PC) and flowable composite (FC) were applied to the attachments.
• Models underwent thermal cycling and immersion in staining solutions to simulate discoloration.
• Color changes (∆E*ab) were measured using a spectrophotometer and analyzed with the CIELAB color space.

Main Results:

• No significant color difference was found between conventional and optimized multiplane attachment designs.
• Flowable composite (FC) groups exhibited significantly less coloration than packable composite (PC) groups for both attachment designs.
• Color change was more pronounced in packable nanocomposite attachments compared to flowable ones.

Conclusions:

• Flowable nanocomposites demonstrate superior color stability compared to packable nanocomposites in clear aligner attachments.
• Flowable nanocomposites are recommended for clear aligner attachments, particularly in the anterior region where esthetics are paramount.
• The choice of nanocomposite material significantly impacts the long-term esthetic outcome of clear aligner therapy.