Primary dental bar use for fibula transplants

Aim: Reconstruction of large mandible defects can be done by using fibula grafts with one- or two stage implantation of dental implants. Preformated guided planning offers the opportunity to use a primary dental arch bar as a fixateure externe. This grounds on a precise guidance through a drilling template. The aim of this study was to determine the accuracy of such a preformed implant-drilling template. Material/methods: In 4 stages 4 dental implants (Astra Dentsply 4,0x10mm) were placed in porcine bone (spongious and long bone) using a preformed drilling template for perpendicular implantation. Bone was not osteotomized. An dental arch bar (Astra ISUS) was screwed to the implants with 9 Ncm torque. Contact x-rays and conical digital volume tomography was done of the implants. The vertical distance between the inner thread and the conical connection was measured on both sides of the implant. Pivot of the implants was measured in two perpendicular planes. The gap difference and angulation of the inner implants were compared. Results: The dental arch bar did not fit to all 4 implants in any stage. The outer implants could only be loaded on one side in 3 stages, in 1 stage none of the outer implants could be loaded. Pivot went up to 6,48° (1st plane) and 12,93° (2nd plane). The inner implants showed a gap difference of 0,56mm (± 0,37) resp. angulation difference of 1,47° (±0,22) - 1st plane/3,83° (±3,28) - 2nd plane - to each other. Discussion/conclusion: Even with guided drilling implant and planned position are differing from each other. Special emphasis has to be set on the inner implants as osteotomy to the outer implants could compensate some deviation - regardless a variation in the position of the inner implants was present. This means primary use of a dental arch bar with four point fixation is limited. A resolution could be the use of a bar separated in the middle to compensate through the mobility of the osteomized segments. In conclusion the use primary dental arch bar is applicable. Keywords: fibula transplant, guided implantation, preformed transplantation, fibula, implantation