Let’s torque about individual tooth movement
Nikhil Gogna discusses single tooth torquing auxiliary and how effective it is for treatment outcomes from a patient’s perspective.
Orthodontists define torque as the buccopalatal crown-root inclination about an x-axis (such as the curvature of the dental arch).
In order to implement torque, larger dimensional archwires are inserted and engaged into brackets. This generates an activating force as you manipulate the wire into the bracket slot.
Such forces create localised pressure and tension thus moving the tooth in a desirable buccopalatal direction.
Torque is important because it enhances the functional occlusion by idealising the inter-incisal angle for stability purposes and sagittal adjustment of the dentition.
Aesthetically, patients will often notice teeth that are ‘under-torqued’ as they aren’t conforming to the appearance of adjacent teeth.
Ways of implementing torque
There are many ways to introduce torque, but most commonly it involves:
- Placing large dimensional rectangular wires – enables expression of the bracket prescription
- Bracket modifications – inverting brackets
- Tweed flat pliers – enables you to place continuous torque in a wire if desired
- Rose torquing pliers – used for individual teeth.
Such pliers aim to make the experience of placing torque more joyful. However, it can be technique sensitive and requires regular reactivation. This means that an inexperienced clinician may be over-zealous in the amount of torque they implement. The resulting effect is the wire not engaging or it being forced into the slot causing bracket debonds.
The single tooth torquing auxiliary
An alternative method that I implement is the incorporation of an 016 stainless steel (ss) wire as an auxiliary, which is modified with a bend (Figure 1) either above or below the bracket slot (depending on whether buccal or palatal root torque is needed).
This wire is placed into the bracket slots and tied with one link of clear powerchain to seat and apply pressure to the required tooth.
The 016ss should span as far posterior as possible to achieve greater pressure.
Due to the 016ss small dimensions, a larger rectangular wire (1825 nickel titanium or 1925ss) can be seated over the wire and engaged into the brackets via modules to compound the torquing effects.
Palatal lateral incisors
In my experience of treating cases, I commonly notice torque issues with palatally displaced lateral incisors. Or, ectopic canines that have been exposed for alignment.
Any orthodontist will tell you for palatal lateral incisors, it’s important to invert the bracket (ie, altering the torque to generate labial root torque rather than palatal root torque) as the lateral incisor aligns.
However, even with these bracket modifications, it may not be enough to generate the desired torque needed to achieve the optimal result.
If I notice that a tooth is under-torqued, I will incorporate this single tooth auxiliary early on in my treatment to enable torque correction as quickly as possible.
Figure 2 demonstrates a case where the UL2 is rotated and slightly palatal.
Figure 3 highlights the 016ss being placed underneath the base archwire (1925ss) and a bend placed incisally – ie, the force pushes the crown palatal and root labial – thus generating labial root torque.
This is clearer in Figure 4 prior to torque correction. It’s evident the crown of the tooth is ‘flared out’ compared to the rest of the dentition. Figure 5 shows this method being successful after two months where labial root torque has been expressed.
The single tooth torquing auxiliary technique is a fast, simple and effective method of implementing torque early in treatment.
In many cases, we tend to manage torque discrepancies at the very end of treatment where the patient wants their braces off and become frustrated at the prolonged treatment time. Inevitably, this can lead to ‘moans and groans’, which the patient will remember. Rather than, appreciating your dedication to improve the torque by five to 10 degrees!