Introduction
The aim of this systematic review was to investigate the ability of vibrational devices to increase the rate of orthodontic tooth movement or reduce pain associated with orthodontic treatment.
Methods
An electronic search for relevant randomized controlled trials (RCTs) was conducted using Medline via OVID (January 1, 1966, through March 30, 2018), and EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials until August 2017. Hand searching of selected orthodontic journals was also undertaken.
Results
Through the electronic searches, 152 titles and abstracts were identified. From these, 10 articles were retrieved for review, and 4 of these met the inclusion criteria. Two additional articles were identified by hand searching. This resulted in 6 studies from 5 separate randomized controlled trials that were included in this systematic review. One RCT reported increased tooth movement with vibrational devices, but the other 4 RCTs reported no difference. Three studies investigated the effect of vibrational devices on pain reduction and found no effect.
Conclusions
The ability of vibrational forces to increase the rate of tooth movement and reduce pain in orthodontic patients has been studied in several RCTs. The results from all but 1 of the included studies indicate no advantage from the use of vibrational devices during orthodontic treatment. Future studies should focus on total treatment duration, the mechanism by which vibration may speed up tooth movement, and the use of vibration with aligners.
Funding
No funding was received for this review.
Highlights
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Six studies from 5 RCTs matched our criteria and were included in this systematic review.
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These studies ranged from unclear to high risk of bias.
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Four of the 5 RCTs did not indicate that vibration affects the rate of tooth movement, total treatment time, or pain.
The duration of orthodontic treatment is an important factor for both orthodontists and their patients. Shorter treatment time may reduce the risk of caries, root resorption, and periodontal breakdown, and most patients desire shorter treatment times simply because of the inconvenience and esthetics of orthodontic appliances. For all these reasons, both patients and orthodontists would prefer the shortest treatment time possible. Different methods have been tried to accelerate tooth movement, such as low-energy laser irradiation, magnetic fields, and pharmacologic intervention using prostaglandin E2 and vitamin D. However, these methods were sometimes associated with undesirable side effects, such as severe root resorption and local pain. Corticotomy-facilitated orthodontics has also been proposed as a method to enhance tooth movement, but it is associated with potential morbidity related to the surgery, high cost, and limited clinical evidence.
The rate of tooth movement is a primary factor in determining treatment time, and this mainly depends on the rate of alveolar bone remodeling. Two hypotheses of alveolar bone remodeling are piezoelectricity generated in the alveolar bone and pressure-tension in the periodontal ligament. In piezoelectricity, applied forces generate an electrical charge that induces the osteogenic response. Since the piezoelectric charges are created only when stress is applied and released, Shapiro et al suggested that orthodontic forces applied to enhance the rate of tooth movement should not be continuous. Therefore, vibrational devices may be suitable for initiating stress-induced charges by rapidly applying an intermittent force. It has also been suggested that vibrational devices enhance tooth movement by reducing frictional resistance to sliding (stick-slip phenomena) between brackets and archwires. Another advantage of using vibrational devices that has been proposed is pain reduction after orthodontic adjustment.
For the above-mentioned advantages, 2 devices that have been or are available commercially provide cyclic forces directly to the teeth during orthodontic treatment: AcceleDent (OrthoAccel Technologies, Bellaire, Tex) and Tooth Masseuse (no longer available). AcceleDent is a small, rechargeable device consisting of an activator and a removable mouthpiece, and it provides a vibrational force of 0.2 N at 30 Hz. The Tooth Masseuse provided a 111-Hz vibrational frequency and 0.06 N of force. For both devices, patients are (or were) instructed to use them for 20 minutes per day by gently biting on the vibrating plastic wafer. Additional vibration devices have been introduced to the market recently, with similar forces and vibrational frequencies.
Orthodontic tooth movement and vibrational devices were studied in animal models with promising results in some reports. A study on Wistar rats with a resonance vibration for 8 minutes per day found 15% more tooth movement in the intervention group compared with the control group. Another study found that application of vibrational forces to Macaca fuscata monkeys for 1.5 hours per day over 3 weeks increased tooth movement 1.3 to 1.4 times more than a static loading force. However, recent animal studies have not found faster tooth movement with vibrational devices. Kalajizic et al studied the effect of cyclic forces (.04 N and 30 Hz) applied twice a week for 10 minutes on the rate of tooth movement on 26 female Sprague-Dawley rats. They noticed that tooth movement was inhibited after application of the cyclical forces. Another study was performed on 64 mice that were divided into 2 groups, control and experimental. The experimental group received low-frequency mechanical vibration at 5, 10, or 20 Hz for 2 weeks, and no difference was observed in tooth movement compared with the control group. A recent review article mentioned the conflicting findings in animal studies and suggested that the rationale for vibration to increase the rate of tooth movement seems contradictory if the primary effects are anabolic. A Cochrane review on nonsurgical adjunctive interventions to accelerate tooth movement was published in 2015; at that time, only 2 randomized controlled trials (RCTs) were identified. Both studies were judged to have a high risk for bias and showed no conclusive positive effect of vibrational devices on tooth movement. Another systematic review, published late in 2017, included both RCTs and controlled clinical trials. The authors reported that there may be weak evidence that vibration could be effective for accelerating canine retraction, but not for accelerating alignment. Since that time, several additional studies on vibration have been published, leading us to undertake this systematic review.
Objective
The aim of this systematic review was to investigate the ability of vibrational devices to increase the rate of tooth movement or reduce pain associated with orthodontic treatment.
Material and methods
The PRISMA checklist was used as a guideline for conducting this systematic review.
Eligibility criteria
The following inclusion criteria were used: (1) type of studies: RCTs; (2) participants: orthodontic patients, aged 11 years and older; (3) types of interventions: vibrational devices to accelerate tooth movement; and (4) comparisons: intervention vs no intervention or comparisons of 2 or more interventions.
Outcomes
The primary outcome was the rate of tooth movement, as measured by various methods, including rate of space closure, rate of tooth alignment, or rate of change in arch perimeter. The secondary outcome was reduction of pain associated with orthodontic tooth movement, using measures such as a visual analog scale (VAS), a validated questionnaire, or a patient interview.
Information sources, search strategy, and study selection
Electronic and hand searches were used to identify all studies, regardless of language.
An electronic search was conducted using Medline via OVID (January 1, 1966, through March 1, 2018), EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials through March 2018. The search strategy is listed in Table I .
| Search engine |
|---|
| Embase |
|
| PubMed |
| (”Orthodontic Appliances”[Mesh] OR vibrat∗ OR vibrational forces OR Acceledent) AND (tooth movement∗ OR orthodontic tooth movement∗). |
| Web of Science and Cochrane Library |
| (tooth movement* OR orthodontic tooth movement*) AND (Acceledent* OR vibrat*). |
A hand search also was undertaken to identify relevant studies from the following journals: American Journal of Orthodontics & Dentofacial Orthopedics , Angle Orthodontist , European Journal of Orthodontics , and Journal of Orthodontics .
When needed, the authors of the included studies were contacted by the review authors to obtain further information about additional or unpublished studies that were eligible for inclusion in the review.
Study selection and data extraction
Two review authors (A.A., K.A.) identified potentially relevant studies independently by screening the titles and abstracts resulting from the searches. The full text of each potentially relevant study was obtained, and inclusion was assessed independently and in duplicate. In case of disagreement regarding the inclusion or exclusion of a study, it was resolved by discussion or referred to a third reviewer (G.H.). The full data extraction was independently performed by 2 reviewers using a specifically designed data-extraction form. The form was piloted, and the interrater agreement was tested using the Cohen kappa statistics (kappa value = 0.88) indicating very good agreement. The primary data extracted from each study were (1) author, journal name, and year of publication; (2) sample size; (3) number of subjects in the intervention group and type of intervention; (4) number of subjects in the control group; (5) mean age; (6) treatment type; (7) outcome measures; (8) duration of follow up; (9) results; and (10) conclusions.
Quality assessment and risk of bias of the selected studies
Independent quality assessment of the included studies was performed ( Table II ). Risk of bias was assessed using Cochrane Collaboration’s tool for assessing risk of bias: http://handbook.cochrane.org.easyaccess2.lib.cuhk.edu.hk/chapter_8/8_5_the_cochrane_collaborations_tool_for_assessing_risk_of_bias.htm .
| Article | Judgment | Support for judgment |
|---|---|---|
| Miles et al ( Australian Orthodontic Journal , 2012) | ||
| Random sequence generation | Unclear | Quote: “Patients who met the inclusion criteria (Figure 1) were randomly assigned in blocks of 6 to ensure even numbers in the control and experimental groups.” Did not mention how the randomization was performed. |
| Allocation concealment | Unclear | Method of concealment was not addressed |
| Blinding of participants and personnel | High risk | Clinician and investigator were blinded, but not participants. Quote: “The clinician was blinded to the study participants at all appointments.” |
| Blinding of outcome assessment | Low risk | Quote: “Identification numbers were assigned to the models prior to measurement to ensure blinding. The irregularity index was measured by one of the authors (PM). After data collection was complete, the model numbers were matched back to the corresponding patients.” “A staff member who was blinded to the study groups and trained in the use of a micrometer measured the VAS data.” |
| Incomplete outcome data addressed | Unclear | Dropout patients were reported, but the reasons were not mentioned. Also, did not mention how missing data from dropouts was managed. |
| Selective reporting | Low risk | All planned outcomes reported. The protocol was not published. |
| Other bias | Unclear risk | Source of funding was not mentioned. |
| Pavlin et al ( Seminars in Orthodontics , 2015) | ||
| Random sequence generation | Low risk | Quote: “Subjects were randomly allocated to either the AcceleDent or. . . . A third-party vendor provided a computer-generated randomization schedule with a block size of 4“ |
| Allocation concealment | Low risk | Quote: “Each subject was assigned to the next of the 48 pre-specified numbers for four stratification combinations and the allocation key was kept locked outside the clinic” |
| Blinding of participants and personnel | Low risk | Quote: “both the investigators and the subjects remained blinded to treatment” |
| Blinding of outcome assessment | Unclear risk | Quote from abstract: “All care providers, investigators, and patients were blinded to intervention assignment.” (The primary author confirmed via personal communication that all investigators, providers, and patients were blinded, but this made it unclear why the study was called a double-blinded, rather than a triple-blinded, study.) |
| Incomplete outcome data addressed | Low risk | Dropout patients were reported and the reasons were mentioned. Intention-to-treat analysis was done. |
| Selective reporting | Low risk | Selective reporting of outcomes: All outcomes outlined in the study registration were reported in the full article. Selective reporting of data: no suggestion of incomplete reporting of data |
| Other bias | High risk | Journal not considered peer-reviewed. The study was sponsored by OrthoAccel. The primary author is a consultant for OrthoAccel. |
| Woodhouse et al ( Journal of Dental Research , 2015) | ||
| Random sequence generation | Low risk | Quote: “The randomization sequence was generated using GraphPad online software” |
| Allocation concealment | Low risk | Quote: “allocation undertaken centrally at King’s College London, independently from the clinical operators after recruitment (allocation concealment)” |
| Blinding of participants and personnel | Unclear risk | Not specifically mentioned in this article, but a follow-up article stated “subjects and treating clinicians were aware of treatment group allocations” |
| Blinding of outcome assessment | Low risk | Quote: “Dental casts were coded so that measurements were undertaken blind” |
| Incomplete outcome data addressed | Low risk | Dropout patients were reported, and the reason was mentioned |
| Selective reporting | Low risk | Selective reporting of outcomes: Trial was registered at ClinicalTrials.gov Selective reporting of data: no suggestion of incomplete reporting of data |
| Other bias | Low risk | Quote: “We are grateful to OrthoAccel Technologies, who graciously agreed to participate in this prospective investigation and provide functional and sham AcceleDent units. This investigation was undertaken independently from OrthoAccel Technologies Inc. The authors received no financial support and declare no potential conflicts of interest with respect to the authorship and/or publication of this article. |
| Miles and Fisher ( American Journal of Orthodontics & Dentofacial Orthopedics , 2016) | ||
| Random sequence generation | Low risk | Quote: “Randomization was performed using permuted blocks of 10 randomly generated numbers with the random generation function in Excel” |
| Allocation concealment | Low risk | Quote: “the numbers were sealed in opaque envelopes and shuffled by a staff member” |
| Blinding of participants and personnel | Low risk | Quote: “Patients were aware of their treatment group. The operator was blinded to the group assignment, and the model assessor (E.F.) was blinded to the treatment group and the model time point” |
| Blinding of outcome assessment | Low risk | Quote: “The same person (E.F.) blinded to the patient group measured the visual analog scale data using a digital caliper” |
| Incomplete outcome data addressed | Low risk | All randomized patients were accounted for |
| Selective reporting | Unclear risk | Selective reporting of outcomes: insufficient information to permit judgment Selective reporting of data: no suggestion of incomplete reporting of data |
| Other bias | Low risk | Study appears to be free of other sources of bias |
| Katchooi et al ( American Journal of Orthodontics & Dentofacial Orthopedics , 2018) | ||
| Random sequence generation | Low risk | Quote: “A block stratified randomization scheme was used in this study. Stratification was achieved by generating a separate block for each combination of age (older than 45 vs younger than 45 years) and sex covariates” |
| Allocation concealment | Low risk | Quote: “Subjects were assigned to the appropriate block of covariates using a random number sequence in separate blocks of 2 to ensure that equal numbers of subjects would receive the active and control devices.” |
| Blinding of participants and personnel | Low risk | Quote: “this was a triple blinded study, in which the subjects, investigators, and assessors were all blinded to the treatment arms |
| Blinding of outcome assessment | Low risk | Quote: “A blinded examiner assessed all digital casts and abstracted data from the questionnaires. Likewise, our statistician was blinded to the study arms throughout the statistical analyses” |
| Incomplete outcome data addressed | Low risk | Dropout patients were reported, and the reasons were mentioned. |
| Selective reporting | Low risk | Selective reporting of outcomes: Trial was registered at ClinicalTrials.gov Selective reporting of data: no suggestion of incomplete reporting of data |
| Other bias | Unclear risk | The study was sponsored by OrthoAccel |
| DiBiase et al ( American Journal of Orthodontics & Dentofacial Orthopedics , 2018) ∗ | ||
| Random sequence generation | Low risk | Quote: “The randomization sequence was generated using GraphPad online software” |
| Allocation concealment | Low risk | Quote: “allocation undertaken centrally at King’s College London, independently from the clinical operators after recruitment (allocation concealment)” |
| Blinding of participants and personnel | Unclear risk | Quote: “subjects and treating clinicians were aware of treatment group allocations” |
| Blinding of outcome assessment | Low risk | Quote: “Dental casts were coded so that all measurements were undertaken blindly. All dental cast linear measurements were carried out blindly by 1 investigator (M.A.). PAR scoring was also conducted blindly for all dental casts by a calibrated examiner (Y.K.)” |
| Incomplete outcome data addressed | Low risk | Dropout patients were reported, and the reason was mentioned. |
| Selective reporting | Low risk | Selective reporting of outcomes: trial was registered at ClinicalTrials.gov Selective reporting of data: no suggestion of incomplete reporting of data |
| Other bias | Low risk | Study appears to be free of other sources of bias. |
∗ This article reports outcomes from the completion of the study of Woodhouse et al from 2015.
For the overall risk of bias ( Table III ), the studies were categorized according to the following.
- 1.
Low risk of bias (plausible bias unlikely to seriously alter the results) if all criteria were met.
- 2.
Unclear risk of bias (plausible bias that raises some doubt about the results) if at least 1 criterion was assessed as having an unclear risk.
- 3.
High risk of bias (plausible bias that seriously weakens confidence in the results) if at least 1 criterion was assessed assessed as having a high risk.
| Entry | Low risk of bias | Unclear risk of bias | High risk of bias |
|---|---|---|---|
| Miles et al ( Australian Orthodontic Journal , 2012) | ✓ | ||
| Pavlin et al ( Seminars in Orthodontics , 2015) | ✓ | ||
| Woodhouse et al ( Journal of Dental Research , 2015) | ✓ | ||
| Miles and Fisher ( American Journal of Orthodontics & Dentofacial Orthopedics , 2016) | ✓ | ||
| Katchooi et al ( American Journal of Orthodontics & Dentofacial Orthopedics , 2018) | ✓ | ||
| DiBiase et al ( American Journal of Orthodontics & Dentofacial Orthopedics , 2018) ∗ | ✓ |
∗ This article reports outcomes from the completion of the study of Woodhouse et al study from 2015.
Statistical analysis
Meta-analysis was not performed due to the heterogeneity of the devices, techniques, and outcomes measured in each study. Since there were only 5 separate trials included in this systematic review, each study will be assessed and discussed separately.
Material and methods
The PRISMA checklist was used as a guideline for conducting this systematic review.
Eligibility criteria
The following inclusion criteria were used: (1) type of studies: RCTs; (2) participants: orthodontic patients, aged 11 years and older; (3) types of interventions: vibrational devices to accelerate tooth movement; and (4) comparisons: intervention vs no intervention or comparisons of 2 or more interventions.
Outcomes
The primary outcome was the rate of tooth movement, as measured by various methods, including rate of space closure, rate of tooth alignment, or rate of change in arch perimeter. The secondary outcome was reduction of pain associated with orthodontic tooth movement, using measures such as a visual analog scale (VAS), a validated questionnaire, or a patient interview.
Information sources, search strategy, and study selection
Electronic and hand searches were used to identify all studies, regardless of language.
An electronic search was conducted using Medline via OVID (January 1, 1966, through March 1, 2018), EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials through March 2018. The search strategy is listed in Table I .
