Samuels R H, DiBiase A T
Department of Orthodontics and Restorative Dentistry, The Glenfield Hospital, The University Hospitals of Leicester, England, UK.
Angle Orthod. 2001 Feb;71(1):44-9. doi: 10.1043/0003-3219(2001)071<0044:CICNMD>2.0.CO;2.
One of the causes of facebow injuries to patients wearing extraoral traction has been the catapult effect of the simple elasticized materials used in the past. A variety of safety or self-releasing modular systems to counteract this catapult effect are currently available. However, the strap extension provided by these modules varies considerably. To reduce the catapult effect to a minimum, it is desirable to fit a system with the minimal travel that will accommodate any changes in distance between the facebow and the back of the head or neck. To ascertain the minimal travel required for the straps, circumferential neck measurements were carried out on 105 children aged between 9 and 14 years. The change in circumference was recorded for 3 different head positions. The mean distance change between the back of the neck and the end of the facebow was 25 mm per side, with a range of 4 mm to 50 mm. This study suggests that on average, modules with a 25-mm extension will be required for cervical traction.
