The present invention pertains to an adjustable curvature toothbrush which comprises (a) an elongated handle (1) having an aperture (2), (b) a cam (3) attached to the handle (1) within the aperture by means of a cam shaft (4), (c) a cam follower (12) which is engaged with, and follows, the cam (3), (d) a flexible brush head (6), (e) bristles (7) supported by the brush head (6), (f) a rigid neck (10) attached to a first end of the brush head (6) and to an end of the handle (1), and (g) a flexible neck (11) attached to a second end of the brush head (6) and to the cam follower (12), whereby the curvature of the brush head (6) can be adjusted by rotation of the cam (3). In another embodiment, the invention pertains to an adjustable curvature toothbrush wherein the cam (3) and cam follower (4) are replaced by a slidable button (17). In yet another embodiment, the invention pertains to an adjustable curvature toothbrush in the form of a compressible closed loop (26).