A dye infusion study of the apical seal of the "injection-molded thermoplasticized gutta percha technique"

PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.Includes colored photographs.Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1985 (Endodontics)Bibliography : leaves 152-163.The "Injection-Molded Thermoplasticized Gutta Percha Technique” was recently introduced to dentistry. This method involves the injection of gutta percha, heated to 160[degrees] C, into the root canal system by way of a pressure syringe, and then compacted by a series of pluggers. However, the dimensional stability of the gutta percha has been questioned. Studies of the thermal characteristics of gutta percha show that when it is heated to a temperature greater than 45-47[degrees] C, irreversible volumetric changes occur. An initial expansion upon heating is followed by shrinkage upon cooling. Forty-six extracted human teeth, comprising 91 canals, were cleaned and shaped according to the technique described by Schilder. The root canal systems were then obturated with injection-molded thermoplasticized gutta percha and Roth cement. The teeth were then prepared for observation by dye penetration (introduced during vacuum and centrifugation), decalcification and cleaning. Adverse results found in this study were: 1) A certain amount of overextensions (underfilled). 2) Cases with the obturation material short of the apical foramen. 3) Lack of homogeneity (voids) in the filling material. 4) High incidence of unsealed canals. 5) Low percentage of demonstrably filled accessory canals