2020 Volume 33 Issue 4 Pages 366-374
Purpose : The influence of the inclination angle of implants with a cantilever on the maximum bending load, amount of deformation, and strain of the collar part was investigated.
Methods : The superstructure was prepared simulating the mesiodistal width (12 mm) of the lower first molar, and to apply a load, 3.25 mm was added to both ends, resulting in a full length of 18.5 mm. Four angles of inclination were set : no inclination, 10, 20, and 30°. A deformation gauge was attached to the tip of the collar part of the fixture, a load was applied at 3.25 mm from the end surface of the superstructure, and each measurement was performed.
Results : When the implant was not inclined, the maximum bending load was about 609 N, and the strains at inclination angles of 10, 20, and 30° were about 18, 21.2, and 31％, respectively, being reduced compared with that of the implant with no inclination angle. The deformation amount increased as the inclination angle increased. Internal observation by CT was performed after measurement. The gap between the collar part and abutment tended to increase as the inclination angle increased. In addition, plastic deformation was noted in the upper part of the screw, but fracture was not observed. The strain of the implant collar region reached 0.1％ when the applied load was 150 N at both inclination angles of 20 and 30°. The strain of the collar part increased as the inclination angle increased, and the load at which the strain reached 0.1％ at all inclination angles was 250 N. No difference was noted in the strain of the collar part at an inclination angle of 0 or 10° at any load.
Conclusion : It was clarified that the limit of the inclination angle of the implant with a cantilever in this study was 10°, at which no difference was noted in strain from that in the preparation with no inclination.
