Intermittent Vibrational Force and Orthodontic Tooth Movement

Irregularity (crowding) of the mandibular (lower) dental arch will be measured as total contact point displacement between the six canine and incisor teeth using digital calipers (150mm ISO 9001 electronic calliper, Tesa Technology, Renens, Switzerland; resolution ± 0.01mm) from stone dental casts. Initial crowding will be measured at T1 prior to the start of treatment. Irregularity will then be measured at T2 (at first archwire change) and the initial rate of orthodontic tooth movement calculated. Irregularity will then be measured at T3 (final alignment of the teeth) to calculate overall rate of alignment.

Subjects will fill out a questionnaire relating to their experiences of pain and discomfort during the first week of fixed appliance treatment. They will be asked to rate their pain on a 10-point visual analogue scale (no pain to extreme pain) at four time-points (4 hours; 24 hours; 3 days and 1 week) following placement of the appliance. They will also record the type and quantity of any analgesia taken during this time

Orthodontic space closure will be measured as the residual distance between canine and second premolar tooth using digital calipers from stone dental casts. This distance will be measured at each visit during space closure to calculate initial and overall rate of space closure.

Root length of the four lower incisor teeth will be measured from a long-cone periapical radiograph taken at the start of treatment (R1) using digital callipers. A second periapical radiograph of the lower incisors will be taken following tooth alignment (R2). The length of the crown from the tip to the cemento-enamel junction will also be measured at the start (C1) and end of alignment (C2). The X-ray enlargement factor will then be calculated as C1/C2, with apical root resorption = R1-R2 x (C1/C2)