Thikriat Al-Jewair BDS, MSc, FRCD (C)
Both corticotomy and low-level laser therapy are safe, but only corticotomy may be effective in accelerating orthodontic tooth movement (OTM). Evidence is insufficient on the effectiveness of electrical current, pulsed electromagnetic fields, and dentoalveolar or periodontal distraction.
In orthodontic patients, do interventions intended to accelerate OTM in addition to conventional orthodontic treatment compared to conventional orthodontic treatment alone produce faster tooth movements?
The authors searched five databases for articles published between January 1990 and August 2011 with no language restrictions. They also searched the SIGLE database for information on grey literature. The authors chose to include randomized (RCTs) and quasi-randomized controlled trials (quasi-RCTs) with no restrictions on the sample size. The participants were healthy orthodontic patients who received an adjunct intervention including low-level laser therapy, corticotomy, electrical current, pulsed electromagnetic fields, and dentoalveolar or periodontal distraction in addition to conventional orthodontic treatment to accelerate OTM. The authors excluded patients who had defects/syndromes in the oral and maxillofacial regions and those having dental pathologies or medical conditions. The primary outcomes of interest were accumulative tooth movement distance or movement rate and the time required to move the tooth to its destination. The secondary outcomes included pain improvement, anchorage loss, periodontal health, orthodontic caries, pulp vitality, and root resorption. The authors used the Cochrane Reviewers' Handbook to assess the risk of bias of the included studies. Statistical pooling of the data was carried out using random or fixed effects model as required. A sensitivity analysis was performed and publication bias was assessed by Egger's and Begg's tests.
A total of nine studies (seven RCTs and two quasi-RCTs) were included, eight of which were split-mouth designs. A total of 101 participants were included and their ages ranged from 10.5 to 26.3 years. The OTM evaluation period ranged from immediately after the intervention application to at least 3 months post-intervention. The meta-analysis showed that low-level laser therapy was not significantly different from the control when the accumulative movement distance was evaluated at one, two, and three months after the intervention. Two studies assessed the effectiveness of corticotomy and reported significant differences favoring the intervention group in both the movement rate (0.265 + 0.036 mm/wk. vs. 0.185 + 0.014 mm/wk., p= 0.001) and the accumulative OTM (one month: [1.89 vs. 0.75 mm]; two months: [1.83 vs. 0.86 mm]; three months: [1.07 vs. 0.93 mm]; and four months: [0.89 vs. 0.85 mm]; p < 0.01 for all). Electrical current vs. no intervention, pulsed electromagnetic fields vs. no intervention, and dentoalveolar vs. periodontal distraction were investigated in three separate studies, each showing statistically significant results.
The review concluded that corticotomy is safe and effective in accelerating orthodontic tooth movement, while low-level laser therapy is safe but unable to accelerate tooth movement. Current evidence is not conclusive about electrical current and pulsed electromagnetic fields. Dentoalveolar or periodontal distraction is promising in accelerating tooth movement, but lacks convincing evidence.
Source of Funding:
National Natural Science Foundation of China, No 81070858.
Importance and Context:
With the increasing number of individuals seeking orthodontic treatment, the demand for accelerated fixed orthodontic treatment is also on the rise. Several methods of accelerating tooth movement have been proposed and are currently being used among clinicians, but evidence on their effectiveness is still lacking.
Strengths and Weaknesses of the Systematic Review:
This is a well-conducted SR and meta-analysis. The reviewers searched five databases without language restrictions, thereby minimizing language bias; however, their search did not include reference lists of identified articles. The reviewers only included studies of the highest level of evidence. They conducted a meta-analysis for the low-laser therapy intervention using the accumulative OTM. They also performed a sensitivity analysis to assess the robustness of the results and assessed the potential for publication bias. The reviewers did not report or examine the effects of gender differences on orthodontic tooth movement of the different interventions. The authors included a wide age range of participants, who were in different stages of growth and development. Also, the minimum sample size for inclusion in the SR was not specified; therefore, studies with small sample sizes were included.
Strengths and Weaknesses of the Evidence:
The authors identified few studies that met inclusion criteria and the sample sizes were small. Although the included studies were of the highest level of evidence, the quality (risk of bias) of the studies was medium or low for the majority of them with only two of high quality. Only four studies used reliable methods to measure tooth movement. These weaknesses introduce measurement bias and limit the internal/external validity of the studies. Corticotomy was evaluated in two studies that found statistically significant effectiveness, but the reviewers did not perform meta-analysis since the data were incomparable. The reviewers identified significant heterogeneity between the studies (reaching 99%) in the meta-analysis of the low-level laser therapy, hence pooling of the evidence is questionable. Cost effectiveness was not evaluated in any of the studies.
Implications for Dental Practice:
Currently, the available evidence does not strongly support the effectiveness of any adjunct intervention for accelerating OTM. A recent systematic review of the literature with less stringent inclusion criteria corroborated that surgically facilitated tooth movements such as corticotomy and dental distraction are safe and result in temporary acceleration of orthodontic tooth movement. However, clinicians need to consider the additional costs of accelerated OTM procedures, especially if the OTM results may be temporary. Further high quality studies are warranted to confirm these findings and help inform clinical decision making. References:  Hoogeveen EJ, Jansma J, Ren Y. Surgically facilitated orthodontic treatment: A systematic review. Am J Orthod Dentofacial Orthop 2014; 145:S51-64.