Effect of low intensity pulsed ultrasound on orthodontically induced root resorption caused by torque: A prospective double blinded controlled clinical trial

• Author / Creator

  Raza, Hasnain

• Orthodontically induced root resorption (OIIRR) is an undesirable consequence of orthodontic treatment and may lead to permanent loss of root structure. A previous clinical trial demonstrated the effect of LIPUS on tipping type of OTM and reported that LIPUS can promote cementogenesis. However, the effect of LIPUS on other types of OTM still remains unclear. Therefore, the aim of this study was to evaluate the effects of LIPUS on OIIRR caused by torque in human subjects. The study sample consisted of 10 healthy human patients between the ages of 12-35 years at the start of the study who required extraction of all first premolars as a part of their routine orthodontic treatment plan. A 15 degree twist was applied in the arch wire using 0.019 x 0.025 TMA wire producing a torque (buccal root) at the bracket level of approximately 5 N-mm. Using a split mouth design, randomization and blinding, one side of the arch received LIPUS for twenty minutes per day for four weeks at an incident intensity of 30mW/cm2 of the transducers surface area. The other side served as a self-control which received a sham transducer. After 4 weeks, all first premolars were extracted for regular orthodontic treatment and a micro-CT analysis was performed of these extracted teeth. Comparison between the two groups was performed using Linear mixed model analysis. LIPUS treated teeth showed significantly less damage compared to control as LIPUS reduced the total volume of resorption lacunae by a mean difference of (0.537 +/- 0.092 mm3) (P<0.001) and percentage of root resorption by a mean difference of (0.33 +/- 0.05) (P<0.001). Also, significantly less number of resorption lacunae were found on all root surfaces in LIPUS group compared to control except for the distal surface. LIPUS significantly reduced the number of RL at the apical third and middle third of the root. This reduction in the severity of OIIRR can be clinically significant considering
  more extensive OIIRR which occurs during the entire course of orthodontic treatment. However, future long term studies are required to determine the efficacy of LIPUS in reducing the severity of OIIRR to a clinical significant level over an extended period of time, as during regular orthodontic treatment.

• Subjects / Keywords

  • Root resorption
  • Torque
  • Low intensity pulsed ultrasound
  • LIPUS

• Graduation date

  Fall 2015

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R39W0967D

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.