CARMEN TODEA, DALIANA MOCUTA, ADRIAN MANESCU, GIANFRANCO SEMEZ, ALESSANDRA GIULIANI, RUXANDRA LUCA, ALEXANDRU OGODESCU LASER USE IN ENDODONTIC FOR INCREASE THE ADHESION OF ROOT CANAL FILLING A SYNCHROTRON RADIATION MICRO TOMOGRAPHY STUDY The aim of the present paper is to explore, through a high-resolution synchrotron radiation-based micro computed tomography experiment, the efficiency of the Er:YAG laser involvement in the debridement of the root canal of pathologic teeth, applied after the chemo-mechanical treatment of the canal. The adhesion quality of root canal filling is the consequence of the root canal cleaning and shaping, thus preventing the leakage. Twelve extracted single-rooted teeth were considered. The first 5 mm of the roots, corresponding to the apical region of the teeth, were initially investigated through high-resolution synchrotron radiation phase-contrast micro computed tomography. Afterwards, a chemo-mechanical endodontic treatment was performed and the same region of the teeth was imaged again. Finally, an Er:YAG laser with PIPS tip treatment was applied on the same teeth and a last tomographic scan was done. The chemo-mechanical treatment properly removed the necrotic tissue only in the upper part of the apical area of root canal, but tissue debris were found in the lower and partially also in the medium and upper part of the apical region, especially when the apical area exhibited a larger curvature. The laser treatment applied afterwards gave good results in terms of removing the debris from the apical area of root canal, mainly when they remained in the main canal. The present study proves the capability of Er:YAG with PIPS tips laser treatment to enhance the removing of tissue debris from the apical region of root canals after a chemo-mechanical treatment. The high-resolution synchrotron radiation-based phase contrast micro computed tomography is the most powerful tool for a non-destructive 3D investigation method of the root canal morphology analysis and a proper characterization technique for the assessment of the endodontic treatment.