PREMOLARS AND UPPER MOLARS
The upper ﬁrst and second premolars have -7° torque and zero angulation. They are interchangeable, ﬁrst and second and left and right. They are shown here without hooks (recommended), but they are available with hooks.
Lower ﬁrst and second premolars
The lower ﬁrst premolar has -12° of torque and the lower second has -17° of torque. They have 2° of tip. Unlike upper premolars they are not interchangeable, ﬁrst and second or left and right. They are shown here without hooks (recommended), but they are available with hooks.
Upper ﬁrst and second molar tubes
The specification for upper first and second molar tubes is -14° torque and 10° of offset, with zero angulation, which is the same as the 1997 prescription. Andrews’ findings gave a figure of -9° torque but experience showed that during treatment the extra torque helps to prevent the palatal cusps of the upper molars from hanging down, which can cause functional interferences. The mini versions of the second molar tubes are shown. Full size tubes are useful when second molars require a lot of tooth movement, but in most cases the authors find that a mini tube works well.
Funnel shaped tube entrances
The upper and lower molar tubes all have a funnel shaped entrance, which is helpful for wire placement, especially in the second molar region.
Upper ﬁrst and second premolar brackets are shown here without hooks, but are also available with hooks. They are interchangeable, ﬁrst and second and left and right.
Lower left ﬁrst and second premolar brackets are shown here without hooks, but are also available with hooks.
The authors’ 1997 values for torque were based on Andrews’ research ﬁndings, and continue to be recommended. They included extra torque control compared with the research values, because torque is not well expressed by the pre-adjusted appliance, and a .019 / .025 working wire does not completely ﬁll the .0227 slot.