Eine neue Methode der extraoralen Zahnfilmfixation

A new method of extraoral x-ray radiographs for the digital subtraction radiographyDigital subtraction radiography (DSR) is a potential tool for implant research in the early healing process after dental implantation or bone graft.The purpose of this investigation was to evaluate a novel fixation system for dental films in order to make reproducible radiographs possible, because a reproducible projection geometry is a prerequisite for the DSR.A conventional extraoral fixation system for occlusal registrations was modified for individual dental film positionings. In order to quantify the occurring central beam deviations n=400 serial radiographs were taken by 11 instructed dentists.By means of an implemented test piece, the projection deviations could be calculated in the vertical, horizontal and total angulation. The clinical applicability was checked with n=10 patients. n=15 digital subtraction radiographs was performed.The analysis of the projection mistakes showed middle deviations in the upper jaw between 1,12° - 1,22°, in the lower jaw between 1,22° - 1,30°. The 95% confidence interval showed angular deviations in the upper and lower jaw less than 2,2° - 2,7°. On a significance level p >= 0,05, no statistically significant differences found in the examined categories. In the patient group, all x-rays were suitable for a digital subtraction.The accuracy in projection geometry achievable with the new system is sufficient for the DSR. Special advantages are the low apparative expenditure and the possibility of the employment in endentulous patients. Parole chiave: Implantologie, Knochenabbau, digitale Subtraktionsradiographie, zahnloser Kiefer