人工歯と従来のデンチャーベースおよびコンピュータ支援設計/コンピュータ支援製造（CAD/CAM）デンチャーベースのせん断接着強度：in vitroでの比較
Subhra Rout1, Reena Mittal1, Ravi Madan1
1Department of Prosthodontics, Kothiwal Dental College and Research Centre, Moradabad, IND.
Introduction:
Complete dentures remain essential for restoring function and aesthetics in edentulous patients; however, tooth debonding continues to be a leading cause of repair. This in vitro study aimed to compare the shear bond strengths of three types of artificial teeth (crosslinked acrylic, composite, and computer-aided design/computer-aided manufacturing as CAD/CAM-milled teeth) bonded to conventional heat-cured polymethyl methacrylate (PMMA) and CAD/CAM-milled denture base resins.
Materials And Methods:
Sixty cylindrical specimens (20 mm in height × 25 mm in diameter) were divided into two main groups (n = 30 each) based on the denture base material: conventional heat-cured PMMA and CAD/CAM-milled PMMA. Each group was subdivided (n = 10) according to tooth type: crosslinked acrylic, composite, and CAD/CAM-milled teeth. Teeth were bonded following the manufacturer's protocols for the CAD/CAM group and the standard packing technique for the heat-cured group. The shear bond strength was measured using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed using one-way and two-way analyses of variance with post-hoc tests (p < 0.05).
Results:
Mean shear bond strength values were as follows: conventional heat-cured base with composite teeth (272.11 ± 85.44 MPa), acrylic teeth (179.09 ± 74.71 MPa), and CAD/CAM-milled teeth (174.47 ± 43.13 MPa); CAD/CAM-milled denture base with CAD/CAM-milled teeth (359.56 ± 76.62 MPa), acrylic teeth (275.51 ± 89.69 MPa), and composite teeth (237.23 ± 75.71 MPa). Two-way analysis of variance revealed significant main effects for both denture base material and tooth type, with a highly significant interaction effect (p < 0.001, η²p = 0.28). The strongest bond was achieved with CAD/CAM-milled teeth on CAD/CAM-milled denture bases, which was significantly higher than that of all other combinations.
Conclusion:
Bond strength is highly dependent on material compatibility. The combination of CAD/CAM-milled teeth and bases from pre-polymerized high-pressure PMMA provides superior adhesion. In conventional heat-cured systems, the composite teeth yield the strongest bond. For optimal clinical durability in digital workflows, matched CAD/CAM tooth-based systems should be preferred.
