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ePaper created 2016-04-19, 11:44:05 | version 1.38.0
vibration therapy trends & applications | 25 ortho 1 2016 relatively low vibrational frequency of the device. For purposes of this discussion low and high fre- quency are defined as: Low frequency–less than or equal to 45Hz; High frequency–greater than or equal to 90Hz. In a 2010 study by Judex and Rubin, ovariecto- mised rats were subjected to either low or high fre- quencyvibration.Boneformationratesforsubjects treated with high frequency were 159% greater when compared to controls, whereas bone forma- tion for low frequency rat subjects were not signifi- cantly different than controls. Trabecular bone vol- umeandthicknesswerealsosignificantlyhigherfor subjects treated with high frequency.13 Similarly Alikhani et al. found a statistically higher rate of al- veolar bone formation (+190%) at higher frequen- cies,witha5min/dayapplication.Inshort,themost pronouncedosteogeniceffectsofvibrationseemto occur well above the AcceleDent’s low vibrational frequency.14,18 Practically speaking, five minutes of daily wear time may be beneficial, as it will reduce the depen- dencyonsignificantpatientcompliance.Inorderto realise the maximum benefits of vibration therapy, shorterweartimeswouldlogicallyincreasecompli- ance, and improve results. Given all other factors being equal, the studies suggest that a higher fre- quencydevicewoulddeliverequivalentamountsof HFA Energy to the dentition in a significantly re- duced timeframe. The future of vibration therapy: Expanded application, multiple benefits Theapparentlimitationsofcurrentcommercially available vibration devices should not diminish the potential importance of vibration therapy. Setting aside applications such as implant dentistry and prosthodontics suggested by the osteogenic prop- ertiesassociatedwithvibrationtherapy,thereareat least four important clinically beneficial orthodon- tic applications that can be anticipated. These po- tential applications are: 1) as a nightly clear aligner seating device; 2) analgesia; relief from normal dis- comfort associated with orthodontic treatment; 3) accelerated orthodontic tooth movement; 4) and enhancement of retention to minimise orthodontic relapse. What follows is a brief examination of each of the four applications of HFLM vibration as an or- thodontic therapy. Improved aligner seating Theimportanceofproperlyseatedaligners,toef- ficient tooth movement in aligner therapy is clearly understood. Improperly seated aligners can slow treatment,forcingpatientstobacktracktoprevious trays,andcreateunintendedcollateraltoothmove- ments, with a consequence being time consuming and costly refinements. Seating recommendations range from using ‘chewies’, to biting on hard ob- jects.Somecliniciansadviseseatingonlywhentrays are new (immediately post change), while others recommend daily seating. With the current seating modalities, it is unlikely that patients consistently seatalignersfully.Aseatingprotocol,thattakesonly five minutes nightly, delivering a range of other pa- tient benefits, would insure that aligners are fully seated throughout treatment. Consistent proper alignerseating,wouldlikelyresultinmoreefficient, faster aligner treatment, even absent biomechani- cal acceleration caused by vibration itself. Non-pharmacological analgesia Discomfort or pain is a common side effect of orthodontic treatment. The forces applied to the dentoalveolar complex which are required to move teeth, compress the periodontal ligament (PDL) causing inflammation. Pain is most notable when seating a new aligner, or immediately after wire changes and adjustments, when pressure on the PDL is at its greatest, and diminishes as the aligner material expands, and/or the dentition comply. In a study accepted in September 2015 by theAngleOrthodontistforfuturepublication,Lo- bre et al found in a randomised clinical trial that vibration therapy ‘resulted in significantly lower perceivedpainandlessOTCmedicationuse.’15 One theory is that vibration restores normal circula- tion to the PDL, which is otherwise restricted by compressive forces. Increased blood flow inter- cepts the ischaemic response and limits inflam- mation. 0 % 5 % 10 % 15 % 20 % 25 % Controls Low Freq High Freq Impact on Bone Volume: High vs Low Frequency Vibration Graphic1:Relativeimpactof frequency on bone morphology Increases in bone volume for high frequency subjects was 25% higher than controls; low frequency subjects were not statistically different than controls. 12016