Self-ligating bracket with sliding cover

1. A self-ligating orthodontic bracket comprising

(a) a base portion adapted to be affixed to a patient's tooth;

(b) an upper body portion, the upper body portion having an archwire slot extending in a mesial-distal direction for receiving an archwire, the upper body portion having a surface on a first side of said archwire slot;

(c) a sliding cover adapted to slide on said support surface and move from an open position exposing said archwire slot, to a closed position covering said archwire slot;

(d) said sliding cover having a main body with a leading edge spanning said archwire slot in said closed position, and a locking tab forward of, and supported by, a flexible neck adapted to flex in a lingual-labial direction, the flexible neck having two ends supported by a surrounding structure of the sliding cover, the flexible neck more flexible than the surrounding structure; and

(e) a ridge on said upper body portion situated on a second side of said archwire slot for engaging said locking tab.

2. The self-ligating bracket of claim 1 wherein said locking tab comprises an inclined or curved front surface and a straight undercut surface whereby to form a hook for locking onto said ridge.

3. A self-ligating orthodontic bracket, comprising

a) a base portion adapted to be affixed to a patient's tooth;

b) an upper portion defining an archwire slot extending in the distal-mesial direction, the upper portion defining dual guide channels extending in the gingival-occlusal direction, and having a ridge; and

c) a planar sliding cover adapted to extend across the archwire slot, such that the cover fits in and slides within the guide channels between an open position and a closed position, the cover having a leading edge, the leading edge having a locking tab with an elastically flexible neck that provides for flexing in a labial direction, the locking tab having a recess whereby the recess engages the ridge when the sliding cover is in the closed position, and whereby the recess and the ridge are each shaped to facilitate flexing of the neck over the ridge when the sliding cover moves towards the closed position and to resist flexing of the neck over the ridge when the sliding cover moves from the closed position towards the open position.

4. The bracket of claim 3 , wherein the ridge has a front side and a back side, such that the front side is curved and the back side is flat, wherein the front side forces the locking tab to flex in a labial direction when it engages the ridge and the locking tab snaps down to engage the back side of the ridge when the sliding cover is in a closed position.

5. The bracket of claim 4 , wherein the locking tab has a straight undercut surface on a back side thereof, which surface latches and engages the back side of the ridge.

6. The bracket of claim 3 , wherein the flexible neck is narrower in width than the locking tab.

7. The bracket of claim 3 , wherein a front surface of the locking tab is curved so as to slide over the front side of the ridge while flexing in the labial direction.

8. The bracket of claim 3 , wherein the archwire slot has a first side and a second side, such that the ridge is located on the first side and a stop groove is located on the second side.

9. The bracket of claim 8 , wherein the stop groove is shaped to engage the locking tab, when the cover is moved from a closed position to an open position, whereby to prevent the cover from sliding out of the guide channels.