Authors: Ahmed El-Angbawi, Grant McIntyre, Padhraig S Fleming, David Bearn

Review question
Do additional non-surgical procedures that claim to accelerate orthodontic tooth movement reduce the overall length of orthodontic treatment?

Background
Throughout the world, orthodontic treatment is used to correct the position of teeth in adolescents and adults when they experience problems with their teeth and bite. Orthodontic appliances can vary in type, and include fixed braces (made up of brackets glued to the teeth and then connected by wires) and removable appliances, e.g. clear aligners, which are a set of clear plastic removable gum shields that fit closely over the teeth. Depending on the tooth and bite problem, the length of time for orthodontic treatment may range from several months to several years. However, most full orthodontic treatments take typically around 20 months. Orthodontic treatment is known to improve how a smile looks, which in turn has a positive impact on patients; however, orthodontic treatment can carry some unwanted risks, such as tooth decay and shortening of tooth roots. Accelerating the rate of tooth movement may help to reduce the length of time needed for a course of treatment and may reduce the unwanted effects of orthodontic treatment that can sometimes occur. Several methods, including surgical and non-surgical treatments, have been suggested to accelerate orthodontic tooth movement. The evidence relating to non-surgical treatments to accelerate orthodontic tooth movement is assessed in this review.

Authors for Cochrane Oral Health carried out this update of the systematic review of existing studies. The evidence on which it is based is current up to September 2022.

Study characteristics

We included 23 studies involving a total of 1027 participants, both males and females, and children and adults. These investigated light vibrational force appliances, low level laser therapy and light-emitting diode (LED) therapy as extras to orthodontic treatment in both private practice and university hospital settings. The trials evaluated different aspects of orthodontic tooth movement and side effects. In the studies, participants were being treated either with fixed orthodontic appliances or orthodontic removable aligners. The participants in all studies had dental (tooth) crowding in one or both arches. Some studies included participants requiring tooth extractions for relief of dental crowding and correction of their bite with space closure, while other studies included participants who did not require dental extractions. The percentage of participants lost to follow-up in the studies included in this review ranged from 0% to 27% of the original samples.

The studies evaluated seven outcomes: duration of orthodontic treatment; number of appointments required to adjust orthodontic appliance, the rate of orthodontic tooth movement at different stages, patient perception of pain and discomfort, patient reported need for painkillers, and unwanted side effects. There were substantial differences between some of the studies; however, it was possible to combine the results of some studies for the light vibrational forces and low level laser therapy. 

Key results

There is low-certainty evidence to suggest that applying light vibrational forces during orthodontic treatment (fixed or removable appliances) has no significant advantage for any of the outcomes assessed. 

There is very low-certainty evidence to suggest that applying low level laser and LED therapy can reduce the duration of the early stage of orthodontic fixed brace treatment (alignment), but it is difficult to estimate the impact of this outcome on the full comprehensive orthodontic treatment duration.

Conclusion

From the limited evidence available, we did not find a benefit from the use of light vibrational forces or photobiomodulation for the reduction of orthodontic treatment duration. However, there could be a potential benefit from photobiomodulation to reduce the length of the early stage of orthodontic treatment only and increase the speed of orthodontic tooth movement; it is important to realise that the results from discrete phases do not necessarily have similar impact on the full orthodontic treatment duration. Further well-designed studies with longer follow-up are needed.

Certainty of the evidence

Our certainty about the evidence is low to very low.

Read the full updated review of Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic treatment here: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD010887.pub3/full