Self-ligating orthodontic brackets having a safety locking feature for ligation cover

Self ligating orthodontic brackets include a bracket base and a ligation cover which interacts with the base in order to provide ligation of at least one arch wire associated with the base. The orthodontic brackets may include one or more of the following improved features: (1) a film hinge about which a ligation cover may rotate; (2) a bearing spring or other flexible feature associated with the ligation cover to provide active ligation; (3) a ligation cover that has sufficient flexibility and resilience to facilitate locking and unlocking relative to the base; (4) a spring or spring-like feature that provides resistance to rotation of the ligation cover relative to the base; (5) a bracket base and ligation cover formed from different types of plastic materials; (6) two or more initially open arch wire slots that can be ligated by a single ligation cover; or (7) a safety locking feature that holds the ligation cover more tightly to the bracket in response to increased arch wire pressure. The orthodontic brackets may comprise one or more different materials, such as plastic, metal or ceramic and may be manufactured as a single piece or in multiple pieces that are later joined together.