The average duration of orthodontic treatment is about 20 months, but it may range from several months to several years. There are potential benefits to patients where treatment can be delivered in a shorter time and in recent decades a number of surgical (eg corticotomy) and non-surgical techniques ( g low level energy laser therapy and light vibrational forces) have been sugested.
The aim of this Cochrane review update was to assess the effect of non‐surgical adjunctive interventions on the rate of orthodontic tooth movement and the overall duration of treatment.
Methods
Searches were conducted in the Cochrane Oral Health’s Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, LILACS BIREME Virtual Health Library, ClinicalTrials.gov and the World Health Organisation International Clinical Trials Registry Platform. Randomised controlled trials (RCTs) in patients receiving fixed or removable orthodontic treatment that included the adjunctive use of non-surgical interventions to accelerate tooth movement were considered. Two reviewers independently selected studies, extracted data and assessed risk of bias using standard Cochrane methods. Meta-analyses were conducted when there was sufficient data.
Results
- 23 studies involving a total of 1027 patients were included.
- Two categories of studies included were identified, light vibrational forces or photobiomodulation (level laser therapy and light emitting diodes).
- 21 of the studies were assessed as being at high risk of bias and none at low risk.
- For all comparisons and outcomes presented, the certainty of the evidence is low to very low.
Light vibrational forces (11 studies)
- No difference was seen for light vibrational force (LVF) compared to control for a range of outcome measures (see table below).
| Outcome measure | No. of studies (patients) | Mean difference (95%CI) |
| Duration of treatment | 2 (77) | -0.61 months (-2.44 to 1.22 |
| Appliance visits | 2 (77) | -0.32 visits (-1.69 to 1.05) |
| Tooth movement during the early alignment stage 4-6 weeks | 3 (144) | 0.12 mm ( -1.77 to 2.01) |
| Tooth movement during the early alignment stage 10-16 weeks | 4 (175) | -0.18 mm (-1.20 to 0.83) |
| Rate of canine distalisation | 2 (40) | -0.01 mm/month (0.20 to 0.18) |
| Tooth movement during en masse space closure | 2 (80) | 0.10 mm per month ( -0.08 to 0.29) |
- No evidence of a difference was found between LVF and control groups in rate of orthodontic tooth movement (OTM) when using removable orthodontic aligners.
- Studies did no show evidence of a difference between groups for our secondary outcomes of patient perception of pain, patient-reported need for analgesics at different stages of treatment and harms or side effects.
LLLT (low level laser therapy) [10 studies]
- Patients in the LLLT group had a statistically significantly shorter length of time for the teeth to align in the early stages of treatment, MD -50 days (95%CI; -58 to -42)[2 studies, 62 patients) and required fewer appointments (-2.3, 95%CI; -2.5 to -2.0) [2 studies, 125 patients].
- There was no evidence of a difference between the LLLT and control groups in OTM when assessed as percentage reduction in LII in the first month of alignment, 1.63% (95%CI; -2.60 to 5.86)[2 studies, 56 patients] or in the second month (percentage reduction MD 3.75%, (95%CI; -1.74 to 9.24)[2 studies, 56 patients].
- However, LLLT resulted in an increase in OTM during the space closure stage in the maxillary arch (MD 0.18 mm/ month (95%CI; 0.05 to 0.33) [1 study; 65 participants]; very low level of certainty) and the mandibular arch (right side MD 0.16 mm/month (95%CI; 0.12 to 0.19) [1 study; 65 patients].
- In addition, LLLT resulted in an increased rate of OTM during maxillary canine retraction, MD 0.01 mm/month (95% CI 0 to 0.02) [1 study, 37 patients]. These findings were not clinically significant. The studies showed no evidence of a difference between groups for our secondary outcomes, including OIIRR, periodontal health and patient perception of pain at early stages of treatment.
LED (light-emitting diode) [2 studies]
- 1 study (34 patients) showed those in LED group required a significantly shorter time to align the mandibular arch compared to the control group, MD= -24.50 days (95%CI; -42.45 to -6.55).
- 1 study (39patients) found no evidence that LED increased the rate of maxillary canine retraction MD 0.01 mm/month (95%CI; 0 to 0.02).
- 1 study assessed patient perception of pain and found no evidence of a difference between groups.
Conclusions
The authors concluded: –
The evidence from randomised controlled trials concerning the effectiveness of non‐surgical interventions to accelerate orthodontic treatment is of low to very low certainty. It suggests that there is no additional benefit of light vibrational forces or photobiomodulation for reducing the duration of orthodontic treatment. Although there may be a limited benefit from photobiomodulation application for accelerating discrete treatment phases, these results have to be interpreted with caution due to their questionable clinical significance. Further well‐designed, rigorous RCTs with longer follow‐up periods spanning from start to completion of orthodontic treatment are required to determine whether non‐surgical interventions may reduce the duration of orthodontic treatment by a clinically significant amount, with minimal adverse effects.
Comments
This Cochrane review updates the 2015 version (Dental Elf – 23rd Nov 2015) and while the number of studies included in the review has increased from 2 to 23 almost all of the included studies (21) are at high risk of bias. The studies are small in size with the numbers of patients ranging from 13 to 33 with several also recruiting both a range of age groups with no subgroup analysis. Consequently, the certainty of the included evidence is of low to very low certainty. The findings suggest there may be some benefit from photobiomodulation during discrete treatment phases but that these effects may not be clinically relevant.
As the main aim of these adjunctive interventions is to reduce orthodontic treatment time it is worth noting that none of the included studies assessed the overall duration of orthodontic treatment or total number of orthodontic appliance visits focusing on discrete treatment phases. The limitations in the evidence means the findings should be viewed very cautiously. As the authors note there is a need for well-designed, conducted and reported RCTs using standardised outcome measures with sufficient participants to detect any clinically and statistically significant difference. Studies should also include the full orthodontic treatment duration and adverse effects.
Links
Primary Paper
El-Angbawi A, McIntyre G, Fleming PS, Bearn D. Non-surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic treatment. Cochrane Database Syst Rev. 2023 Jun 20;6:CD010887. doi: 10.1002/14651858.CD010887.pub3. PMID: 37339352.
Other references
Dental Elf – 10th Apr 2019
Orthodontic treatment: Do vibrating devices accelerate tooth movement?
Dental Elf – 23rd Nov 2015
Little research on non-surgical interventions to accelerate orthodontic treatment
Picture Credits
Photo by Quang Tri NGUYEN on Unsplash
