SELF-LIGATING ORTHODONTIC BRACKETS HAVING A SAFETY LOCKING FEATURE FOR LIGATION COVER

摘要

Self ligating orthodontic brackets include a bracket base, a ligation cover and a special safety locking feature that prevents inadvertent unlocking of the cover. This feature is provided by a ligation cover (150) hingedly attached to the base (144) by a film hinge (162), and a trapezoidal locking tongue (154) that is slidably received within a corresponding angled key way. The movement of the locking tongue is restrained (154) in response to flexation by the cover (150). An arch wire (147) shortens the length of the cover (150) by causing it to bulge upward in the middle relative to the base (144). The surfaces (157, 159) defining the angled key way restrict movement of the locking tongue (154) so that it is necessarily pulled more tightly into the angled key way, resulting in a tighter locking connection between the cover (150) and the base (144).