皆さんこんにちは。

今回もテーパーと根尖拡大号数に関する文献です。

下顎大臼歯の近遠心根管に対して

解剖学的根尖孔は全て20番で形成し

そこから1mm手前において半数は35番まで拡大

残り半数は60番までステップバック法で形成しています。

The aim of this investigation was to assess canal cleaning following shaping with hand files of greater taper.

Thirty mesial canals and 30 distal canals in mandibular molars were prepared with .08 and .10 hand files of greater taper, respectively. Following initial preparation, 0.02 instruments were used incrementally shorter in a stepback manner. In half the canals instrumentation was performed to size 35 1 mm short of the canal terminus. In the other half the series was continued through to size 60 using stepback increments of half to one millimetre as appropriate (foramen size was maintained at size 20 in all groups). Sodium hypochlorite (4.5%) and REDTA (17%) were used as irrigants for all groups. Cleaning efficacy was evaluated by scoring the amount of remaining debris using a light microscope (x50) and calibrated eyepiece micrometer (range 0-3).

Canals stepped back through to a size 60 were significantly cleaner than those instrumented to a size 35 only (Mann-Whitney P < 0.05).

Refining the apical region of canal preparation by stepping back through to a size 60 reduced remaining debris following shaping with files of greater taper.

つまり、根尖拡大号数が小さい時には

ステップバック法にてテーパーを大きくすることで

根管内を効果的に清掃できるということです。

引用文献

Lumley PJ.

Cleaning efficacy of two apical preparation regimens following shaping with hand files of greater taper.

Int Endod J.2000 May;33(3):262-5.