Study On The Application Of The Dental Microscopy In The Operation Of Root Tip Resection

Objective: To investigate the application of the dental microscopy in the operation of root tip resection, we compare the apical sealabi1ity of different materials in the operation of root tip resection with or without the treatment of the dental microscopy. Then to provide the theory references for clinical treatment.Methods: 80 premolars were collectted in clinic, and divided to 4 groups randomly after conventional root canal preparation and canal obturation , and 20 premolars in every group. Then the teeth were treated with or without dental microscope as follws:①apectomy②retrofi1led with MTA or silver amalgam.1. Comparison of the apical sealability 10 teeth were selected from every group and immersed in methylene blue solution.The dental bodies were longitudinally split and the deepest depth in the hollow of the dye penetration was measured by the dissecting microscope .2. The detection of scan microscopy Choose the rest teeth from every group, cut the transections parted from the root tip 1.5mm, which were treated by dehydration, drying and gold sputtering.The distances between the materials and the dentin walls in the transections were measured under the SEM.Results:1. Comparison of the apical sealability: The depth of the penetration of the MTA group with the dental microscopy was obviously lesser than that without the dental microscopy, and the silver amalgam group with the dental microscopy was obviously lesser than that without the dental microscopy,too.2. The detection of scan microscopy showed that the gaps between the materials and the dentin walls of the MTA group with the dental microscopy was obviously lesser than that without the dental microscopy, and the silver amalgam group with the dental microscopy was obviously lesser than that without the dental microscopy,too.Conclusion:1. The apical sealability can be increased with the application of the dental microscopy during the operation of root tip resection. However, the degrees of improvement is different for different materials.2.The apical sealability of MTA is obviously better than silver amalgam.