Shear bond strength of 3-dimensional-printed orthodontic brackets

Area of Science:

• Orthodontics
• Biomaterials Science
• Dental Materials

Background:

• Three-dimensional (3D) printing offers customization in orthodontic bracket fabrication.
• Evaluating the bond strength and adhesive behavior of 3D-printed brackets with different base designs is crucial for clinical adoption.

Purpose of the Study:

• To compare the shear bond strength (SBS) and adhesive remnant index (ARI) of 3D-printed orthodontic brackets with custom, macroretentive, and standard base designs.
• To analyze the surface morphology of remaining adhesives using scanning electron microscopy (SEM).

Main Methods:

• Sixty maxillary premolars were divided into three groups (n=20 each) based on bracket base design: custom, macroretentive, and standard.
• Brackets were 3D printed, bonded with composite resin, and subjected to SBS testing.
• Adhesive remnant analysis (ARI) and SEM examination of bracket bases and tooth surfaces were performed.

Main Results:

• The custom base design group exhibited the highest SBS (8.05 ± 4.69 MPa), significantly greater than the standard group (P = 0.017).
• Higher adhesive retention on the tooth (ARI score 2) was observed in the custom and macroretentive groups compared to the standard group.
• SEM analysis indicated that most adhesive remained on the teeth across all groups.

Conclusions:

• Custom mesh designs on 3D-printed orthodontic brackets enhance bond strength and adhesive retention.
• 3D-printed orthodontic brackets with custom base designs show potential for clinical use.
• Further research simulating oral conditions is recommended to confirm clinical applicability.