open access

https://hdl.handle.net/2115/56204

The effect of combination of mechanical and chemical enlargement through the root canal on sealability of vertical root fracture gap using 4 - META/MMA - TBB resin

日本語

封鎖性

2014-03-25

Hokkaido University

https://www.lib.hokudai.ac.jp/dissertations/copy-guides/

The basics of conservative treatment of vertical root fracture is bonding and sealing the gap of root fracture. It is difficult to seal the gap surely from the root canal side. Grinding the gap wall using the ultrasonic endodontic file from the root canal side improve sealability of the gap, on the other hand, there may happen to be excessive and insufficient grinding. It is possible that dissolving the root canal wall with 10% citric acid 3% ferric chloride solutions (10-3) and 10% sodium hypochlorite(NC) enlarge the region difficult for mechanical expansion. The purpose of this study was to evaluate the sealability after enlarging the gap of root fracture with chemical method and together with the ultrasonic endodontic filing and chemical agents. In the first experiment, 1 millimeter thick dentin pieces were cut out from extracted human teeth, fractured in the direction of tooth axis, restored to the original position and held. The gaps were treated by 10-3 for 5 minutes and NC for 2 minutes one time(one time group) , three times(three times group) and no time (control group). In all groups, gaps were bonded using 4META/MMA-TBB resin(Super Bond) to seal the fractured gaps. After that all pieces were tested by dye penetration tests and the gaps were microscopically measured. In the second experiment, extracted human teeth were fractured vertically and restored. The gaps were treated by the following methods. 1) no treated (control group), 2) ground from the root canal wall side with an ultrasonic endodontic file, until the Root ZX reading showed 1.0(grinding group), 3) treated by 10-3 for 5 minutes and NC for 2 minutes three times(chemical group), 4) treated by 3) method after grinding by 4) method(combination group). In all groups, gaps were sealed using Super Bond, tested by dye leakage tests and microscopically measured. In the first experiment, enlarged width was significantly larger in three times group than control and one time groups. The rate of dye penetration was significantly smaller in three times group than control and one time groups. In the second experiment, the rate of dye penetration was statistically significantly smaller in combination group than other groups. These findings indicate that the combination use of chemical method and mechanical method with the ultrasonic endodontic file in the gap of root fracture is effective to enhance the sealability of the fractured gap while preventing over grinding. Key Words: vertical root fracture, intra-oral bonding treatment, sealability

甲第11259号

博士(歯学)

(主査) 教授 川浪 雅光, 教授 八若 保孝, 教授 佐野 英彦

歯学研究科（口腔医学専攻）

博士論文

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