Lower ﬁrst and second molar tubes
The lower ﬁrst molar has -20° of torque and the lower second molar has -10° of torque. They have zero offset and zero angulation. As with the uppers, they have a funnel-shaped entrance, for easy wire placement.
Mini lower second molar tubes
Full size lower second molar tubes are used to correct difﬁcult rotated or tipped teeth, but in many treatments the mini second molar tube is preferred. Despite its small size it provides good tooth control in routine cases. It is more comfortable for the patient than the full size tube, with fewer interferences and it became available in late 2018.
Treating to a Class II molar relationship
When treating to a Class II molar relationship, the lower ﬁrst molar tubes are often used in the upper arch on the contralateral side (see the ‘Fundamentals of Orthodontic Treatment Mechanics’ page 61). Thus the lower right tube can be used on the upper left molars, and the lower left tube can be used on the upper right molars. Some orthodontists use normal upper molar tubes to achieve most of the tooth movements, and then to switch to lower ﬁrst molar tubes for ﬁnishing. Others use lower ﬁrst or second molar tubes in the upper from the outset when treating to a Class II relationship.
Lower left ﬁrst and second molar tubes. In many treatments the mini second molar tube is preferred.
There is extra torque control compared with the research values, and this helps to prevent lower molars from rolling lingually and causing interferences.
When treating to a Class II molar relationship, the lower ﬁrst molar tubes are often used in the upper arch on the contralateral side.