ProTaper Gold, EdgeTaper Platinum, Flex Gold, Pro-T ロータリーシステムの機械的特性

Mechanical Properties of ProTaper Gold, EdgeTaper Platinum, Flex Gold and Pro-T Rotary Systems.

抄録

目的:

本研究の目的は，エッジテーパープラチナ［ETP（先端25，テーパ0.06）］，フレックスゴールド［FG（先端25，テーパ0.08）］，プロT［PT（先端25，テーパ0.08）］およびプロテーパゴールド［PTG（先端25，テーパ0.08）］システムについて繰り返し疲労，ねじれ挙動および耐曲げ性を評価することである．

OBJECTIVE: The aim of this study was to evaluate the cyclic fatigue, torsional behavior and bending resistance of EdgeTaper Platinum [ETP (tip 25, taper 0.06)], Flex Gold [FG (tip 25, taper 0.08)], Pro-T [PT (tip 25, taper 0.08)] and ProTaper Gold [PTG (tip 25, taper 0.08)] systems.

方法:

ETP，PT，FG，PTGの回転機器を使用した（n=30）．体温（35°±1°C）で，角度60°，曲率半径5mmの人工ステンレス鋼製管路を用いて繰り返し疲労試験を行った．破断までの時間とサイクル数（NCF）を記録した．ねじり試験では，ISO 3630-1に従って，先端から3mmの位置で破断するまでのトルクと回転角度を評価した．また，走査型電子顕微鏡（SEM）を用いて，各断片の破断面を観察した．曲げ試験では，60°の角度のたわみで器具を曲げるのに必要なトルクを評価した．データは一元配置分散分析およびTukey検定を用いて分析し，有意水準は5%とした．

METHODS: Rotary instruments of ETP, PT, FG, and PTG were used (n=30). Cyclic fatigue tests were performed using an artificial stainless-steel canal with a 60o angle and a 5-mm radius of curvature at body temperature (35°±1°C). The time and number of cycles to fracture (NCF) was recorded. The torsional test evaluated the torque and angle of rotation to failure at 3 mm from the tip according to ISO 3630-1. The fractured surface of each fragment was observed by using scanning electron microscopy (SEM). The bending test evaluated the torque required to bend the instruments at an angular deflection of 60°. Data were analyzed using one-way ANOVA and Tukey tests, and the level of significance was set at 5%.

結果:

ETPは破折までの時間およびNCFが全群で最も高かった（P<0.05）．ねじり強度はPTGが最も高く，FGがそれに続いた（P＜0.05）．回転角度はETPが最も高く，PT，PTGがそれに続いた（P＜0.05）．曲げ強さはFGが最も高く，次いでPTGであった（P＜0.05）．

RESULTS: The ETP had highest time until fracture and NCF than all the groups (P<0.05). The PTG had the highest torsional strength, followed by FG (P<0.05). The ETP had the highest angular rotation, followed by PT and PTG (P<0.05). The FG showed the highest bending resistance, followed by the PTG (P<0.05).

結論:

ETPとPTは，FGとPTGに比べ，高い耐繰り返し疲労性と高い角たわみ値を示し，低い曲げ力を示した．PTGは最も高いねじり強度を示し，最も低い耐サイクル疲労性を示した．

CONCLUSION: In conclusion, the ETP and PT exhibited higher cyclic fatigue resistance, higher angular deflection values and lower bending force than FG and PTG. The PTG instruments showed the highest torsional strength and the lowest cyclic fatigue resistance.