An in vitro study of the passivity of splints in dental trauma

Objectives: The purpose of this research was to evaluate the passivity of splints which were constructed with orthodontic materials since a force could unintentionally be generated by the appliance and perturb the healing process of the injured teeth. Methods: A specific data acquisition system, with a 2D force transducer, was developed to evaluate its passivity. Four types of splints were studied on a maxillary dental arch model and the splints were constructed with 0.559 mm standard edgewise brackets, with stainless steel square or round orthodontic wires and with 0.254 mm preformed ligatures or 3.05 mm elastomeric ones. The studied orthodontic wires were straight-lengthed or Arch Blank preformed types and three sizes of square wires and five sizes of round ones were tested. Results: The orthodontic appliances were rarely passive but the splints constructed with elastomeric ligatures and an Arch Blank preformed wire were significantly different from those constructed with stainless steel ligatures and a straight wire or with stainless steel ligatures and an Arch Blank preformed wire or with elastomeric ligatures and a straight wire (P < 0.05). The best control of passivity was obtained with the 0.432 mm × 0.432 mm splints (P < 0.05) and the mean force generated by those appliances was 0.13 × 10−2N. Conclusions: The choice of orthodontic materials influenced the passivity of dental splints and it would seem that elastomeric ligatures and an Arch Blank preformed wire should be used for its construction.