Review question
What effect do non-surgical adjuncts have on the length of time it takes for teeth to move when treated with fixed braces, and the overall time required for orthodontic treatment?
Background
Throughout the world, orthodontic treatment is used to correct the position of teeth in adolescents and adults when they experience problems. Braces are orthodontic appliances made up of brackets glued to the teeth and then connected by wires in order to exert pressure on the teeth to move them and improve their positioning. Depending on the problem, the length of time for treatment may range from several months to several years. However, most treatments take on average, around 24 months. 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, such as tooth decay and the shortening of the tooth root. Several methods, including surgical and non-surgical treatments, have been suggested to accelerate orthodontic tooth movement. The evidence relating to non-surgical procedures to accelerate orthodontic tooth movement is assessed in this review.
Study characteristics
Authors for the Cochrane Oral Health Group carried out this review of existing studies. The evidence on which it is based is current up to 26 November 2014.
We included two studies involving a total of 111 participants in this review. A single orthodontic specialist in a private practice in Australia carried out one study, while the other study was conducted on patients treated by orthodontic residents in a university hospital seating in the United States of America. In one study, the age of participants ranged from 11 to 15 years old, and in the second, the average age of participants was 21 years. The studies evaluated the additional use of two devices that use light vibrational forces - Tooth Masseuse in people receiving conventional fixed appliance treatment during the tooth alignment stage and OrthoAccel for those receiving conventional fixed appliance treatment for the space closure stage in orthodontic treatment. Participants receiving additional treatment with the devices were compared to those receiving only the conventional treatment. The trials evaluated different aspects of orthodontic tooth movement and side effects.
Key results
The studies evaluated three outcomes: rate of tooth movement; patient perception of pain and discomfort, and unwanted side effects. There were substantial differences between the studies, which meant that we were unable to combine the results.
From the limited evidence available, it is not possible to establish if the use of vibrational forces during treatment with fixed orthodontic appliances has a significant beneficial or harmful effect on either the rate of orthodontic tooth movement or the duration of treatment.
Quality of the evidence
The quality of evidence was very low.
There is very little clinical research concerning the effectiveness of non-surgical interventions to accelerate orthodontic treatment. The available evidence is of very low quality and so it is not possible to determine if there is a positive effect of non-surgical adjunctive interventions to accelerate tooth movement. Although there have been claims that there may be a positive effect of light vibrational forces, results of the current studies do not reach either statistical or clinical significance. Further well-designed and rigorous RCTs with longer follow-up periods are required to determine whether non-surgical interventions may result in a clinically important reduction in the duration of orthodontic treatment, without any adverse effects.
Accelerating the rate of tooth movement may help to reduce the duration of orthodontic treatment and associated unwanted effects including root resorption and enamel demineralisation. Several methods, including surgical and non-surgical adjuncts, have been advocated to accelerate the rate of tooth movement. Non-surgical techniques include low-intensity laser irradiation, resonance vibration, pulsed electromagnetic fields, electrical currents and pharmacological approaches.
To assess the effect of non-surgical adjunctive interventions on the rate of orthodontic tooth movement and the overall duration of treatment.
We searched the following databases on 25 November 2014: the Cochrane Oral Health Group's Trials Register (November 2014), the Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library 2014, Issue 10), MEDLINE via OVID (1946 to November 2014), EMBASE via OVID (1980 to November 2014), LILACS via BIREME (1980 to November 2014), metaRegister of Controlled Trials (November 2014), the US National Institutes of Health Trials Register (ClinicalTrials.gov; November 2014) and the WHO International Clinical Trials Registry Platform (November 2014). We checked the reference lists of all trials identified for further studies. There were no restrictions regarding language or date of publication in the searches of the electronic databases.
We included randomised controlled trials (RCTs) of people receiving orthodontic treatment using fixed appliances along with non-surgical adjunctive interventions to accelerate tooth movement. We excluded non-parallel design studies (for example, split-mouth) as we regarded them as inappropriate for assessment of the effects of this type of intervention.
Two review authors were responsible for study selection, risk of bias assessment and data extraction; they carried out these tasks independently. Any disagreements were resolved by discussion amongst the review team to reach consensus. The review authors contacted the corresponding authors of trials to obtain missing information and data to allow calculation of mean differences (MD), 95% confidence intervals (CI) or risk ratios (RR) when these were not reported.
We included two studies in this review, which were both assessed as being at high risk of bias. The two studies, involving a total of 111 participants, compared the use of Tooth Masseuse and OrthoAccel with conventional treatment mechanics during orthodontic alignment and canine retraction phases, respectively. Both studies included objective assessment of the amount or rate of tooth movement, but we were not able to meta-analyse this data as they used different outcome measurements at different stages of the orthodontic treatment process. One study measured subjective evaluation of pain and discomfort and the other evaluated adverse effects. The studies did not directly report either the duration of orthodontic treatment or the number of visits during active treatment.
Using the Tooth Masseuse with 111 Hz at 0.06 Newtons (N) for 20 minutes daily resulted in greater reduction in irregularity in the lower incisor region over 10 weeks, assessed using Little's Irregularity Index (LII) with a mean difference (MD) of 0.6 mm (95% confidence interval (CI) -0.94 to 2.34) when compared to the control group. Pain and discomfort increased at six to eight hours after arch wire placement and after seven days, with minimal difference between the intervention and control groups. No statistical tests were provided for either variable and the differences between the two groups were not clinically important.
Using OrthoAccel with 30 Hz at 0.25 N for 20 minutes daily produced a higher rate of maxillary canine distalisation in comparison to the control group (MD 0.37 mm/month; 95% CI -0.07 to 0.81; P = 0.05). Whilst this difference suggested 50% faster tooth movement using the vibrational appliance, the absolute differences were marginal and deemed clinically unimportant. Similar levels of non-serious adverse effects were reported in the intervention and control groups with a risk ratio of 0.96 (95% CI 0.32 to 2.85).
Overall, the quality of the evidence was very low and therefore we cannot rely on the findings.