Effect of Mechanical Vibration on Root Resorption
Condition: Vibration; Exposure
MeSH terms: Root Resorption
Study type: Interventional

Summary: 
      The aim of this study was to investigate the effect of mechanical vibration on root
      resorption with or without the application of orthodontic force.

      Twenty patients who required maxillary premolar extractions as part of their orthodontic
      treatment were randomly separated into two groups of 10: no-force group and force group.
      Using a split-mouth procedure, each patient's maxillary first premolar teeth were randomly
      assigned as either vibration or control side in both groups. Buccally directed vibration of
      113 Hz, using an Oral-B HummingBird device with a modified tip, was applied to the maxillary
      first premolar for 10 mins/day during 12 weeks. After the force application period, the
      maxillary first premolars were extracted and scanned with micro-computed tomography.
      Fiji(ImageJ) which made slice-by-slice quantitative volumetric measurements was used for
      resorption crater calculation. Total crater volumes was compared with Wilcoxon and
      Mann-Whitney U tests.
    

Detailed description: 
      The sample included 40 maxillary first premolars from 20 orthodontic patients (7 boys and 13
      girls; range: 15.08-18.58 years; mean: 16.77 years) who required bilateral maxillary first
      premolar extractions as part of their orthodontic treatment. They were recruited according to
      strict selection criteria as described previously.These included need for bilateral maxillary
      first premolar extractions (necessitating moderate anchorage) and fixed appliance treatment;
      permanent dentition; completion of apexification; similar minimal crowding on each side of
      the maxillary arch; no previous orthodontic or orthopedic treatment; no unilateral or
      bilateral posterior crossbites; no craniofacial anomaly; no history of trauma, bruxism, or
      parafunction; no past or present signs and symptoms of periodontal disease; no significant
      medical history that would affect the development or structure of the teeth and jaws and any
      subsequent tooth movement; and no history of asthma. The sample size was calculated by using
      Piface 1.72, and guaranteed 82.56% power. This number was reached by considering the standard
      deviation of 0.46mm3 in our previous similar study. True difference of means was estimated at
      0.2mm3, and type I error(α) was accepted as the standard value .05.

      Ethics approval was obtained from the Ethics Committee of Bulent Ecevit University (2012/23).
      All subjects and their guardians consented to participate in this study after receiving
      verbal and written explanations.

      Impressions were taken with alginate of the maxillary jaw only to construct the appliance.
      The study model was obtained by pouring hard plaster. On this model, the transpalatal arch
      was formed by bending a 0.09 mm steel wire between the maxillary right and left first molar
      teeth. To prevent potential contact of the teeth during buccal movement to the transpalatal
      arch, occlusion rising acrylic plates were added. The acrylic plates were of mean 2mm
      thickness to only include occlusion of the first molar teeth. After fitting the transpalatal
      arches in the mouth, light-cured glass ionomer cement (TransbondTM Plus, 3M Unitek, Monrovia,
      USA) was applied to the maxillary first molar teeth of all the patients. After these
      procedures, the patients were randomly separated into 2 equal groups. Randomization was made
      using the Excel program (Microsoft, Redmond, WA, USA), and allocation was hidden in
      consecutively numbered, closed envelopes. Blinding was used for treatment and outcome
      assessments.

      No-force group: The right and left side first premolar teeth were randomly assigned
      (split-mouth design) so that mechanical vibration was applied in the buccal direction on one
      side and the other side was used as the premolar tooth control group. Oral B Hummingbird
      device (Procter&Gamble, USA) with a modified tip was used for the application of vibration.
      The tip was positioned mid-buccally of teeth to perform buccally directed vibration.
      HummingBird is prescribed maximum period 0.00885s corresponding to 6800RPM or 113Hz of the
      motor. The vibration procedure was applied for 10mins/day during the period of 12 weeks. At
      the end of the 12th week, the first stage was completed and the first premolar teeth were
      extracted.

      Force group: The right and left side first premolar teeth were randomly assigned (split-mouth
      design) so that mechanical vibration was applied in the buccal direction to one side and the
      other side was used as the premolar tooth control group. As in no-force group, same device
      procedure was used for the application of vibration. Self-ligating Speed (Strite Industries,
      Cambridge, Ontario, Canada) tubes and brackets with 0.022×0.026 inch slots were bonded to the
      buccal surfaces of the right and left first molar teeth and first premolar teeth.150g of
      buccally directed forces, producing by a 0.017×0.025-in beta-titanium-molybdenum alloy (3M
      Unitek, Monrovia, Calif) cantilever spring, were applied to premolar teeth on both side. The
      force magnitude was measured with a strain gauge (Dentaurum). At the end of the 12th week,
      the first stage was completed and the first premolar teeth were extracted.

      The premolar teeth were extracted under local anesthesia by the same dental practitioner in
      all cases. To remove blood and tissue remnants from the teeth after extraction, they were
      washed with non-pressurized isotonic solution without touching the root surfaces, then each
      tooth was placed in a 5 ml sterile tube containing 10% formalin solution (Sarstedt Ag & Co.,
      Nümbrecht, Germany). After 2 weeks the formalin solution was changed and no other procedure
      was applied until examination of the roots.

      Scanning of the root surfaces was applied using the SkyScan-1172 x-ray micro-tomography
      device (SkyScan, Aartselaar, Belgium). To calculate the volume of the resorption craters
      isolated on the axial slices, open-source Fiji (ImageJ) software was used. Using the convex
      hull module in the software, a line was drawn joining the edges of the resorption craters and
      the area below the line was calculated as the volume (Figure 4). Volumetric changes in the
      craters on the root surfaces were evaluated both locally and totally.

      The data were statistically analyzed using SPSS version 24.0(IBM Corp., Armonk, NY, USA). The
      Shapiro-Wilk test was used to test for normal distribution. Wilcoxon test was applied to the
      within-group comparisons of the resorption volumes formed at different levels(cervical, mid,
      apical) on different surfaces of the root(buccal, palatal, mesial, and distal). The
      Mann-Whitney U-test was used in comparisons between the groups.
    

Intervention name(s): Mechanical Vibration
Intervention type(s): Diagnostic Test
Intervention description(s): Oral B HummingBird device (Procter&Gamble, USA) with a modified tip was used for the application of vibration. The tip was positioned mid-buccally of teeth to perform buccally directed vibration. HummingBird is prescribed maximum period 0.00885s corresponding to 6800RPM or 113Hz of the motor. The vibration procedure was applied for 10mins/day during the period of 12 weeks.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Diagnostic