| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
The persent study was designed with the purpose of elucidating the factors necessary for achieving close and tight root canal swaling on the curved root canal. For the experiment, transparent root canal models were prepared by varying diameter, taper and curvature of the root canal. For lateral condenstation, stainless stell spreader (SS) and nickel-titanium spreader (NT) were used. Condensation of gutta-percha point was evaluated on the surface of root canal model. For the case of curved root canal with inadequate root canal preparation, the filling situation of lateral condensation was also evaluated by the same procedure.
1. Influence of root canal diameter : It was found that the thickness (diameter) of root canal gave influence on the remaining condition of the sealer in the direction toward root canal tip. Thick root canal could be more easily inserted to the depth of root canal in both SS and NT, and condensation of gutta-percha point at root canal tip could be easily achieved.
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Influence of root canal : In a model with lower root canal taper, much of the sealer remained on root canal wall at root canal tip in both SS and NT.When the root canal taper was increased, it was possible to insert the spreader to the depth of root canal and it provided better effect on condensation. This contributed to the decrease of the amount of the sealer remaining on root canal wall. Filling condition was somewhat poorer in NT than SS.This may be attributed to the fact that NT showed poorer performance of insertion into root canal because it was slightly thicker in diameter than SS and also that its flexibility exerted reverse effect and sufficient condensation could not be attained.
3. Influence of curvature of root : It appeared that the curvature of root canal exerted less influence on the filling condition in both SS and NT.However, when NT was used, there was less difference in the performance of insertion of the spreader due to the curvature.
4. Influence of the inadequate shape of root canal preparation : In case of root canal with inadequate root canal preparation, different types of cutting marks were observed on root canal wall depending on the types of preparation methods. Sealer remained much on this part, and condensation of gutta-percha point was insufficient. On the zip, excessive cutting on outer curve of root canal tip, meander phenomenon of the point due to plugger effect of the spreader was observed.
These results suggest that, in case of curved root canal, it is important to give adequate taper in root canal preparation for the purpose of achieving satisfactory root canal filling. Less
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