A computer-guided minimally-invasive technique for orthodontic forced eruption of impacted canines. [Progettazione e realizzazione di una tecnica minimamente invasiva computer-guidata per l'ancoraggio ortodontico dei canini inclusi]

BACKGROUND: The aim of this study was to develop a computer-guided minimally-invasive protocol for the surgical application of an orthodontic traction during the forced eruption of an impacted canine. METHODS: 3Diagnosys® software was used to evaluate impacted canines position and to plan the surgical access, taking into account soft and hard tissues thickness, orthodontic traction path and presence of possible obstacles. Geomagic® software was used for reverse engineering and RhinocerosTM software was employed as three-dimensional modeller in preparing individualized surgical guides. Surgical access was gained flapless through the use of a mucosal punch for soft tissues, followed by a trephine bur with a pre-adjusted stop for bone path creation. A diamond bur mounted on SONICflex® 2003/L handpiece was used to prepare a 2-mm-deep calibrated hole into the canine enamel where a titanium screw connected with a stainless steel ligature was screwed. In-vitro pull-out tests, radiological and SEM analysis were realized in order to investigate screw stability and position. RESULTS: In two out of ten samples the screw was removed after the application of a 1-kg pull-out force. Radiological and SEM analysis demonstrated that all the screws were inserted into the enamel without affecting dentine integrity. CONCLUSIONS: This computer-guided minimally-invasive technique allowed a precise and reliable positioning of screws utilized during the orthodontic traction of impacted canines.