 Radiographic evaluation All radiographs are evaluated by one examiner LR who is blinded to the clinical results and to the time point the particular radiographs had been taken. All radiographs are digitalized using a computer program SIDEXIS nextGeneration 1.51, Sirona, Bensheim, Germany and a flatbed scanner Microtek ScanMaker 4, Microtek, Hsinchu, Taiwan with 600 dpi resolution and 8 bit grey values. The image files are stored as TIFF files and analyzed using the above mentioned computer program SIDEXIS nextGeneration 1.51, Sirona, Bensheim, Germany and a 19 flat Screen Totoku CCL 192 plus, Totoku Electric, Ueda, Japan. 