Perioperative progress check of interdental forces following extraction of the third molars. A prospective long-term...

With the aim of checking the progress of mesially directed forces in a complete dental arch, we measured the interdental frictional forces in a population of 44 patients with erupting maxillary and mandibular third molars. The measurements were taken preoperatively and postoperatively 1, 2, 3, 7, and 12 weeks and also 1 year after extraction or surgical removal of the third molars in all 4 quadrants. In addition, the interdental frictional forces of a total of 40 test persons in 3 control groups were similarly measured in a state of inertia, after a period of 1 hour spent in supine position, and after a 5-minute period of chewing activity. Over the first 4 to 12 weeks the interdental forces showed a significant postoperative average decrease of 16.1% in the maxilla and 18.0% in the mandible. After 1 year the average reduction in the level of interdental forces in the patient population was 10.3% in the maxilla and 10.9% in the mandible. A significant postoperative reduction in force of 40.7% was registered for third molars with a mesial angle of 66 degrees to 90 degrees to the tooth axis of the second molar in the mandible. Following a 1-year control period, the level of interdental force in the patient population was found to be on average 27.4% below the preoperative baseline value. In control group I, the margin of fluctuation of interdental forces in a state of inertia was +/- 3.5% over a 3-month period. In control group II, a significant average decrease in interdental forces was measured in the maxilla (15.1%) and mandible (13.2%) following a 1-hour period in supine position. In control group III, a non-significant average reduction in interdental forces was established in the maxilla (7.8%) and mandible (8.6%) following a 5-minute period of chewing activity.