Why orthodontists get sued

Effect of Low Intensity Pulsed Ultrasound (LIPUS) on Tooth Movement and Root Resorption: A Prospective Multi-Center Randomized Controlled Trial

The aim of this study was to evaluate the possible effect of low intensity pulsed ultrasound (LIPUS) on tooth movement and root resorption in orthodontic patients. Twenty-one patients were included in a split-mouth study design (group 1). Ten additional patients were included with no LIPUS device being used and this group was used as the negative control group (group 2). Group 1 patients were given LIPUS devices that were randomly assigned to right or left side on upper or lower arches. LIPUS was applied to the assigned side that was obtained by randomization, using transducers that produce ultrasound with a pulse frequency of 1.5 MHz, a pulse repetition rate of 1 kHz, and average output intensity of 30 mW/cm². Cone-beam computed tomography (CBCT) images were taken before and after treatment. The extraction space dimensions were measured every four weeks and root lengths of canines were measured before and after treatment. The data were analyzed using paired t-test. The study outcome showed that the mean rate of tooth movement in LIPUS side was 0.266 ± 0.092 mm/week and on the control side was 0.232 ± 0.085 mm/week and the difference was statistically significant. LIPUS increased the rate of tooth movement by an average of 29%. For orthodontic root resorption, the LIPUS side (0.0092 ± 0.022 mm/week) showed a statistically significant decrease as compared to control side (0.0223 ± 0.022 mm/week). The LIPUS application accelerated tooth movement and minimized orthodontically induced tooth root resorption at the same time.

Repair of orthodontically induced root resorption by ultrasound in humans

Root resorption is an adverse outcome of orthodontic tooth movement. In addition to the iatrogenic response and compromising the crown-root ratio, root resorption has led to increased malpractice litigation against orthodontists. A clinically acceptable method of treating root resorption has not been validated in the literature to date. Previous research has shown that low-intensity pulsed ultrasound (LIPUS) can enhance healing of various types of traumatized connective tissues and stimulate dental tissue formation. The purpose of this study was to evaluate the effect of LIPUS on the healing process of orthodontically induced tooth-root resorption in humans. Twelve orthodontic patients who were seeking orthodontic treatment that necessitated extracting the first premolars before mechanotherapy participated in this study. For each patient, buccally activated springs were used to tip the maxillary first premolars buccally, with an initial force level of 50 g; the springs were checked weekly to ensure continuous force levels. A short period of LIPUS was applied to 1 side of each patient's mouth, with the other side used as a control. After 4 weeks, the experimental premolars of all patients were extracted, and the premolars of 6 patients were studied by scanning electron microscopy (SEM); the premolars of the other 6 patients were studied histologically. The number and total area of resorption lacunae as examined by SEM were compared between the LIPUS-treated and the control premolars with a t test. The SEM study showed a statistically significant decrease in the areas of resorption and the number of resorption lacunae in the LIPUS-exposed premolars. Histologic examination showed healing of the resorbed root surface by hypercementosis. The results of this study provide a noninvasive method for reducing root resorption in humans.