並列タイトル等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
授与機関名Hokkaido University（北海道大学）
一般注記垂直歯根破折に対する保存治療の基本は,破折間隙を接着し,封鎖することである.超音波エンドファイルを用い,根管内から破折線を切削すると,破折間隙の封鎖性は向上するが,過剰切削や切削不足が生じることが課題である.一方,化学的な根管壁の溶解によって,機械的拡大が困難な部位の根管拡大が可能であるので,本研究では破折間隙の切削と化学的拡大を併用することで,接着後の封鎖性が向上するかを検討した.実験1.ヒト抜去歯から厚さ1㎜の象牙質片を作製して破折させ,復位固定した.破折間隙に対して,処理群は10%クエン酸3%塩化第二鉄溶液(10-3溶液) 5分, 10%次亜塩素酸ナトリウム溶液(NC) 2分の処理を1回あるいは3回行った.未処理群では破折間隙の処理は行わなかった. 3群ともスーパーボンド(SB)で破折間隙を接着し,色素侵入試験を行うとともに破折間隙幅を計測した.その結果,間隙幅は3回処理群が他の2群より有意に広く(p＜0.05) ,色素侵入率は3回処理群が他の2群より有意に小さかった(p＜0.05) .実験2.ヒト抜去歯を垂直破折させて復位固定し,破折間隙に対して以下の処置を行った.①未処理群:処理なし.②化学的拡大群: 10-3溶液5分, NC2分の処理を3回.③形成群:ソルフィーZXのアピカルストップ値を1.0に設定して超音波エンドファイルで破折間隙を切削.④併用群:③の後に②の処理. 4群ともSBで破折間隙を接着後,色素侵入試験を行った.その結果,併用群においては歯根表面に切削が達している試料はなく,その色素侵入率は他の3群と比較して有意に小さかった(p＜0.05).以上の結果から,超音波エンドファイルによる破折間隙の切削と化学的な拡大を併用することは,過剰な切削を防止して封鎖性を向上するのに有効である.
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
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Hokkaido University（北海道大学）. 博士(歯学)
DOIinfo:doi/10.14943/doctoral.k11259
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受理日（W3CDTF）2015-05-01T13:23:17+09:00
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