Narrow ceramic self-ligating orthodontic bracket
A ceramic orthodontic bracket has a centrally located clip for retaining an archwire in an archwire slot. The body of the bracket includes a mesial section, a distal section, and a bridge section, wherein the bridge section extends through, and retains, the clip. The bridge section also includes a recess adjacent to the bridge section that facilitates debonding of the bracket from a patient' s tooth. Preferably there are gaps on one or both sides of the clip to allow space for debonding of the bracket by applying a mesial-distal compressive force on the bracket and fracturing the bracket along the recess. This configuration allows the overall mesial-distal width of the bracket to be reduced, thereby facilitating the bonding of brackets to narrow and/or maloccluded teeth. Another embodiment includes a stop member that is connected to the base of the bracket and retains the clip on the bridge section.
1. An orthodontic bracket comprising:
a mesial section;
a distal section;
a bridge section connecting the mesial section and the distal section, wherein the mesial section, the distal section and the bridge section comprise a ceramic material, and wherein the bridge section includes a line of weakness comprising a section having a reduced cross-sectional area and extending in a generally occlusal-gingival direction; and
wherein the bridge section further includes a groove that extends along the line of weakness and interrupts the continuity of the lingual surface of the bridge section;
an archwire slot extending across the mesial section and the distal section in a generally mesial-distal direction and located in a facial direction from the bridge section;
a recess that extends in a generally occlusal-gingival direction and is located in a lingual direction from the bridge section; and
a clip coupled to the bridge section for releasably retaining an archwire in the archwire slot, wherein at least a portion of the clip extends in the recess, wherein the clip has an opening facing the facial direction, wherein the bridge section extends through the clip, and wherein the clip surrounds the line of weakness, and wherein the line of weakness enables the bracket to be debonded from a tooth by pivoting one or both of the mesial and distal sections in directions toward each other.
2. The bracket of claim 1 further comprising an archwire slot liner that extends along the archwire slot.
3. The bracket of claim 2 , wherein the archwire slot liner does not have an occlusal wall and/or gingival wall along at least a portion of the archwire slot.
4. The bracket of claim 1 wherein the clip releases the archwire from the archwire slot in a generally facial direction whenever the archwire exerts a force greater than about 1.4 kg on the bracket in the same direction.
5. The bracket of claim 1 wherein the clip releases the archwire from the archwire slot in a generally facial direction whenever the archwire exerts a force greater than about 0.7 kg on the bracket in the same direction.
6. The bracket of claim 5 wherein the clip comprises a shape-memory alloy.
7. The bracket of claim 5 wherein the bridge section includes a facial side, and wherein the clip includes protrusions that extend towards each other and contact the facial side of the bridge section.
8. The bracket of claim 7 wherein the clip further comprises a pair of tabs to facilitate assembly of the latch to the bridge section, wherein the tabs extend away from each other in generally occlusal and gingival directions.
9. The bracket of claim 8 wherein the pair of tabs is located in a facial direction from the pair of protrusions.
10. The bracket of claim 5 wherein the clip is generally “C”-shaped and comprises a pair of arm portions, wherein the arm members move away from each other to receive an archwire.
11. The bracket of claim 1 wherein the bracket includes at least one tiewing.
12. The bracket of claim 1 , wherein the line of weakness comprises a frangible web.