Self-ligating bracket with sliding cover
A self-ligating orthodontic bracket has a sliding archwire cover that has a top surface congruent with the top surface of an upper body portion having an archwire slot. The cover has a resilient locking tab that slides across the slot, bending upward as it encounters a ridge on the other side of the slot, and latching to the ridge to secure the cover in a closed position. The cover has a modified dovetail shape with flared bottom portions that slideably engage guides for reciprocal opening and closing sliding motion. A groove in the slide support track engages the locking tab in the open position preventing it from disengaging from the upper body portion.
1. A self-ligating orthodontic bracket comprising:
a body having a base surface adapted to be affixed to a tooth, said body having a first upper tie wing portion and a second upper tie wing portion, said first upper tie wing portion being separated from said second upper tie wing portion by an archwire slot extending through the body in a mesial-distal direction;
said second upper tie wing portion having a ridge, said ridge having a front surface adjacent said archwire slot and a back surface;
a ligating archwire cover slidably mounted on said first upper tie wing portion, and supported by said first upper tie wing portion when said cover is in an open position exposing said archwire slot, said archwire cover having a centrally disposed, forwardly extending flexible locking tab, wherein said locking tab is adapted to flex in a labial direction when said cover is moved from said open position toward a closed position covering said archwire slot and said locking tab engages said ridge, and is adapted to flex in a lingual direction to latch said archwire cover in a closed position thereby covering said archwire slot when said locking tab moves over said ridge wherein said locking tab comprises a slanted nose portion for engaging said front surface of said ridge, and further comprises a hook portion for latching said cover to the back surface of said ridge,
and wherein said first upper tie wing portion includes a groove for engaging said hook portion when said archwire cover is moved from a closed position to an open position.
2. The self-ligating orthodontic bracket of claim 1 wherein said front surface of said ridge is slanted or curved.
3. The self-ligating bracket of claim 1 wherein said archwire cover further includes a pair of side wing portions on either side of said locking tab, said pair of side wing portions each having a chamfered lingual surface adjacent leading edges thereof.
4. The self-ligating bracket of claim 1 wherein said archwire cover further includes a pair of side wing portions on either side of said locking tab, said pair of side wing portions each having an underside pocket adapted to receive an insertable, lingually flexing leaf spring for engaging an archwire when said sliding cover is moved from an open position toward a closed position.
5. The self-ligating bracket of claim 1 wherein said ligating archwire cover further includes a pair of side wing portions on either side of said locking tab, said pair of side wing portions each having a length that spans said archwire slot to thereby slideably engage a ledge on said second upper tie wing portion when said archwire cover is moved to a closed position.