Effect of denture tooth manufacturing and adhesive materials on bond strength of 3D-printed denture base

Abstract

Background: 3D printing enhances denture fabrication, but the bond between printed teeth and bases is often weaker than traditional methods. This study investigates the effect of tooth-adhesive combinations on bond strength to enhance clinical reliability in digital dentistry. Material and Methods: Forty-eight cylindrical 3D-printed denture bases were bonded with either 3D-printed (PT) or milled (MT) teeth using three bonding materials: NextDent (ND), Super-Bond (SUP), and Unifast Trad (UNI) (n=8/group). The PT-ND group served as the control. Specimens were subjected to shear bond strength testing using a universal testing machine at 0.5 mm/min, with a 4 mm shear pin, and failure modes were analyzed under a stereomicroscope. Results: Tooth type, bonding material, and their interaction significantly influenced bond strength (P<0.05). MT-UNI and MT-SUP demonstrated the highest values (92.33 ± 4.90 N; 87.34 ± 2.41 N), while MT-ND had the lowest (11.72 ± 1.94 N). Among PT groups, PT-SUP performed best (45.59 ± 3.47 N), followed by PT-ND (34.12 ± 3.38 N) and PT-UNI (23.68 ± 4.14 N). High-strength groups exhibited predominantly mixed failure (MT-SUP, MT-UNI, PT-SUP), while lower-strength groups showed adhesive failure. (MT-ND, PT-UNI). Conclusions: Bond strength is influenced by both tooth material and bonding agent. From the results, Unifast Trad is optimal for milled teeth; Super-bond is best suited for printed teeth. Material selection is critical for improving durability and chairside efficiency in digital prosthodontics.