PG A brilliant article on Accelerated tooth movement

LONG, PYAKUREL, WANG, LIAO, ZHOU, LAI 
Interventions for accelerating orthodontic tooth movement. A systematic review
Angle Orthodontist, Angle Orthod. 2013;83:164–171

In this systematic review, the authors have analyzed nine eligible studies of five types of interventions, within which six outcomes were evaluated. Among the nine included studies, 2 used mini- screws as anchorage to retract canines, while the remaining seven studies used first molars. For the seven studies, measurements of the moved distances of canines may be influenced by mesial movements of the first molars. However, in consideration of the methods for the measurements, the authors suggest that 4 studies  employed reliable methods and were not influenced by the mesial movement of first molars.

Low-Level Laser Therapy
For this intervention, accumulative moved distance, periodontal health, and root resorption were evaluated, but a meta-analysis was conducted only for accumulative moved distance. The pooled mean differences between the two groups regarding accumulative moved distance evaluated over 1,2 and 3 months intervals indicated that low-level laser therapy was unable to accelerate orthodontic tooth movement. However, two studies showed consistent results that laser therapy was safe in terms of periodontal and root health.
Therefore, the authors suggest that low-level laser therapy is safe regarding periodontal and root health and that it is unable to accelerate orthodontic tooth movement.

Corticotomy
The results from two included studies showed consistent results that corticotomy can accelerate orthodontic tooth movement. Moreover, both employed reliable methods to measure tooth movement and specified and used a similar start time of force applications between two groups, which would lend more credence to their results since the rates of tooth movement into healed and recent extraction sites are significantly different.  Moreover, the results showed that corticotomy in conjunction with mini-screws can dramatically augment posterior anchorage, which is of prime importance since effective anchorage would greatly improve orthodontic treatment results.

Since corticotomy is per se a surgical intervention on alveolar bones, it may have adverse effects on periodontal tissues. However, in this systematic review, neither study indicated that corticotomy would damage periodontal health, except that gingival index scores increased in the experimental group 1 study. The authors however suggest this may be simply a response of gingiva to alveolar healing, since alveolar healing following surgery takes at least 4 months. Thus, dental hygiene should be paid special attention during the healing stage after corticotomy.
Therefore, the authors suggest that corticotomy is relatively safe and is an effective intervention to accelerate orthodontic tooth movement.

Electrical Current
In this systematic review, only accumulative moved distance was evaluated. Kim et al revealed that electrical current was capable of accelerating orthodontic tooth movement. This study employed a reliable method to measure tooth movement. However, it did not specify the start time of canine retraction after first premolar extraction, which decreases the reliability of the results since canine retraction speed into healed and recent extraction sites differ.  Moreover, since only females were included in this study,the authors do not know the intervention effects in males.
Therefore, regarding unreliable methodology and results, we cannot determine whether electrical current would accelerate orthodontic tooth movement.

Pulsed Electromagnetic Fields
In this systematic review, only accumulative moved distance was assessed. Showkatbakhsh et al showed that a pulsed electromagnetic field was capable of accelerating orthodontic tooth movement. However, this study suffered from several drawbacks.
First, the study measured moved distance using an unreliable method. Second, this study did not specify the start time of canine retractions after extractions of the first premolars. Furthermore, the quality assessment indicates that this study is of low quality, which further limits the reliability of this study.
Therefore, with regard to unreliable methodology and results, the authors cannot determine the effectiveness of pulsed electromagnetic fields on accelerating orthodontic tooth movement.

Dentoalveolar Distraction vs Periodontal Distraction

Kharkar et al  showed that dentoalveolar distraction can accelerate orthodontic tooth movement compared with periodontal distraction. However, this study suffered from a significant drawback: the distractors were activated 2 days after first premolar extractions for dentoalveolar distraction, while they were activated immediately after first premolar extractions for periodontal distraction, rendering the two modalities incomparable. In addition, this study was of low quality. Thus, the authors cannot determine which modality would be more effective in accelerating orthodontic tooth movement. But with regard to the great differences in treatment duration between dentoalveolar or periodontal distraction and conventional treatment (10–20 days vs 6–9 months), the authors suggest that dentoalveolar or periodontal distraction is promising in clinical practice.
Moreover, both techniques cause negligible anchorage loss, and all the moved teeth were vital after 1 year for both techniques. Dentoalveolar distraction did not cause root resorption, while periodontal distraction did which may be attributed to extended duration of applied force required for periodontal distraction.
Thus, the authors suggest that dentoalveolar or periodontal distraction is safe and that the unreliable methodology and results limited the interpretation that these techniques are effective in accelerating orthodontic tooth movement.

The results of this systematic review must be interpreted with caution because of several limitations, including the small number of high-quality studies and limitation of statistical pooling due to clinical or methodological heterogeneity and noncomparability of outcome data.

CONCLUSIONS
1. Low-level laser therapy is safe but unable to accelerate orthodontic tooth movement; corticotomy is safe and able to accelerate orthodontic tooth movement.
2. Current evidence does not reveal whether electrical current and pulsed electromagnetic fields are effective in accelerating orthodontic tooth movement; dentoalveolar or periodontal distraction is promising in accelerating orthodontic tooth movement but lacks convincing evidence.