RoDent : Robotic Dentistry : Computer aided dental implant positioning system

A study was carried in conjunction with the Orthodontic department at Halmstad General Hospital in Sweden to investigate the possibility of reducing cost and manufacture time of dental implant drill guides. The current system involves sending a digital image in STL format to the Materialise factory in Belgium where information of the position of dental implants is translated onto a moulded mouthpiece. Drill guides are placed in the mouth piece which is then returned to the surgeon. The mouthpiece complete with drill guides is then placed in the patients mouth and used as a guide for the implant drill holes. The cost of 10000 sek and a turnaround time of 2 weeks gave rise to the need for a faster and cheaper solution. A new mouthpiece was designed comprising of a solid cube which could be clearly seen on the x-ray. Linearisation of the cube faces is used to find a reference point from which to drive a 5 axis drilling platform. The mouthpiece is placed in the drill platform which is driven by stepper motors which in turn are controlled by a microcontroller. Co-ordinates are entered via a PC interface. The PC software then translates these co-ordinates into motor steps which are sent to the microcontroller. The drill platform then positions the mouthpiece in order to drill guide holes for the dental implants. The study showed that the machine design gave an acceptable degree of accuracy and repeatability. Further enhancements could be made by automating the detection of the cube using image analysis techniques. The study was also limited by the lack of graphical and geometrical data concerning the position of the implant. For the purpose of this study the co-ordinates for the implants guides is entered by hand. It was concluded that further software and hardware enhancement would be needed before the application could be developed commercially