The removal of gutta-percha and root canal sealers from root canals.

The removal of gutta-percha from root-filled teeth is required for re-treatment of failed endodontic treatment and to prepare a space for placement of a post. Complete removal of filling material and sealer is a requirement for success. A review was undertaken of the current literature on methods of gutta-percha and sealer removal. Clinical recommendations based on current evidence are included. A combination of methods may be required to remove filling materials effectively.

An evaluation of .06 tapered gutta-percha cones for filling of .06 taper prepared curved root canals.

AIM: To compare the area occupied by gutta-percha, sealer, or void in standardized .06 tapered prepared simulated curved canals and in mesio-buccal canals of extracted maxillary first molars filled with a single .06 gutta-percha point and sealer or lateral condensation of multiple .02 gutta-percha points and sealer. METHODOLOGY: Simulated canals in resin blocks with either a 30 degrees curve and radius of 10.5 mm (n = 20) or a 58 degrees curve and 4.7 mm radius (n = 20) and curved mesio-buccal canals of extracted maxillary first molars (n = 20) were prepared using .06 ProFiles in a variable tip crown-down sequence to an apical size 35 at 0.5 mm from the canal terminus or apical foramen. Ten 30 degrees and 58 degrees curved resin canals and 10 canals in the extracted teeth group were obturated with .02 taper gutta-percha cones and AH 26 sealer using lateral condensation. The time required to obturate was recorded. The remaining canals were obturated with a single .06 taper gutta-percha cone and AH 26 sealer. Excess gutta-percha was removed from the specimens using heat and the warm mass vertically condensed. Horizontal sections were cut at 0.5, 1.5, 2.5, 4.5, 7.5 and 11.5 mm from the canal terminus or apical foramen. Colour photographs were taken using an Olympus 35 mm camera attached to a stereomicroscope set at x40 magnification, and then digitized using a flatbed scanner. The cross-sectional area of the canal contents was analysed using Adobe PhotoShop. The percentage of gutta-percha, sealer or voids to the total root canal area were derived and data analysed using unpaired Student's t-test and the Mann-Whitney U-test. RESULTS: In the 30 degrees curved canals the levels had between 94 and 100% of the area filled with gutta-percha with no significant difference (P > 0.05) between the lateral condensation and single cone techniques. In the 58 degrees curved canals the levels had 92-99% of the area filled with gutta-percha, with the single cone technique having significantly (P < 0.05) more gutta-percha fill at the 2.5 mm level only. In the mesio-buccal canals of the teeth the levels had between 72 and 96% of the area filled with gutta-percha with no significant difference (P > 0.05) between the lateral condensation and single cone technique. The time for obturation was significantly (P < 0.05) greater for lateral condensation compared with the single cone technique in all groups. CONCLUSIONS: The .06 taper single cone technique was comparable with lateral condensation in the amount of gutta-percha occupying a prepared .06 tapered canal. The .06 single cone technique was faster than lateral condensation.

Electronic apex locators.

Prior to root canal treatment at least one undistorted radiograph is required to assess canal morphology. The apical extent of instrumentation and the final root filling have a role in treatment success, and are primarily determined radiographically. Electronic apex locators reduce the number of radiographs required and assist where radiographic methods create difficulty. They may also indicate cases where the apical foramen is some distance from the radiographic apex. Other roles include the detection of root canal perforation. A review of the literature focussed first on the subject of electronic apex location. A second review used the names of apex location devices. From the combined searches, 113 pertinent articles in English were found. This paper reviews the development, action, use and types of electronic apex locators.