Orthodontic shear bond strength and ultimate load tests of CAD/CAM produced artificial teeth

Objectives To investigate whether artificial CAD/CAM processed (computer-aided design/manufacturing) teeth could be a feasible option for the production of dental in vitro models for biomechanical testing. Material and methods Disks (n= 10 per group) made from two different CAD/CAM-materials, one fiber-reinforced composite (FRC; Trinia, Bicon) and one polymethylmethacrylate-based resin (PMMA; Telio CAD, Ivoclar Vivadent), as well as bovine teeth (n =10), were tested for their shear bond strength (SBS) and scored according to the adhesive remnant index (ARI). In addition, CAD/CAM-manufactured lower incisor teeth were tested for their ultimate load (F-u). Results With regard to SBS, both PMMA (17.4 +/- 2.2 MPa) and FRC (18.0 +/- 2.4 MPa) disks showed no significant difference (p = 0.968) compared to bovine disks (18.0 +/- 5.4 MPa). However, the samples differed with regard to their failure mode (PMMA: ARI 4, delamination failure; FRC: ARI 0 and bovine: ARI 1.6, both adhesive failure). With regard to F-u, FRC-based teeth could withstand significantly higher loads (708 +/- 126 N) than PMMA-based teeth (345 +/- 109 N) (p < 0.01). Conclusion Unlike PMMA-based teeth, teeth made from FRC showed sufficiently high fracture resistance and comparable SBS. Thus, FRC teeth could be a promising alternative for the production of dental in vitro models for orthodontic testing.