Theoretical Distribution of Gutta-percha within Root Canals Filled Using Cold Lateral Compaction Based on Numeric Calculus

This study aimed to present a new method based on numeric calculus to provide data on the theoretical volume ratio of voids when using the cold lateral compaction technique in canals with various diameters and tapers. Twenty-one simulated mathematical root canal models were created with different tapers and sizes of apical diameter, and were filled with defined sizes of standardized accessory gutta-percha cones. The areas of each master and accessory gutta-percha cone as well as the depth of their insertion into the canals were determined mathematically in Microsoft Excel. When the first accessory gutta-percha cone had been positioned, the residual area of void was measured. The areas of the residual voids were then measured repeatedly upon insertion of additional accessary cones until no more could be inserted in the canal. The volume ratio of voids was calculated through measurement of the volume of the root canal and mass of gutta-percha cones. The theoretical volume ratio of voids was influenced by the taper of canal, the size of apical preparation and the size of accessory gutta-percha cones. Greater apical preparation size and larger taper together with the use of smaller accessory cones reduced the volume ratio of voids in the apical third. The mathematical model provided a precise method to determine the theoretical volume ratio of voids in root-filled canals when using cold lateral compaction.

根管内牙胶充填材料去除方法和效果

根管治疗术是目前牙髓病及根尖周病最为有效的治疗方法,在临床上广为应用。但根管治疗失败仍时有发生,这就需要去除原有充填材料,重新进行根管预备、消毒和充填。牙胶是目前应用最为普遍的充填材料。文章将对根管再治疗过程中原有牙胶充填材料去除的方法、效果及安全性做一概述。