下顎大臼歯の峡部含有中顎根管系からの硬組織破片の除去における超音波および超音波活性化潅流のマイクロCT評価

Micro-CT evaluation of sonically and ultrasonically activated irrigation on the removal of hard-tissue debris from isthmus-containing mesial root canal systems of mandibular molars.

抄録

目的:

下顎大臼歯の中根管系に蓄積した硬組織残渣（AHTD）の除去に対する超音波および超音波活性化灌流の有効性をマイクロCT分析により評価する。

AIM: To evaluate the efficacy of sonically and ultrasonically activated irrigation on removal of accumulated hard-tissue debris (AHTD) in mesial root canal systems of mandibular molars using micro-computed tomographic (micro-CT) analysis.

方法:

下顎大臼歯の中根で、2つの独立した根管が先端側で峡部により結合しているもの（Vertucci type II）40本を選択した。根管にはReciproc R25インスツルメントを使用し、10.5μmの解像度でスキャンした。その後、n=10根を4つの最終灌流群（EndoActivatorを用いた音波活性化灌流（EA）またはEDDY（ED）、超音波活性化灌流（UAI）、活性化なしの手動灌流（MI））にグループの平均値と分散がほぼ同じになるように割り付けた。最終的なイリゲーションは、1% NaOCl 5mL と 15% EDTA 5mL を用いて、4×20秒の活性化時間で5分間行った。

METHODOLOGY: Forty mesial roots of mandibular molars with two independent canals joined apically by an isthmus (Vertucci type II) were selected. The root canals were instrumented using Reciproc R25 instruments, and specimens were scanned at a resolution of 10.5 μm. Subsequently, n = 10 roots were assigned to each of the four final irrigation groups such that the group means and variances were almost identical: sonically activated irrigation with EndoActivator (EA) or EDDY (ED), ultrasonically activated irrigation (UAI) and manual irrigation without activation (MI). The final irrigation procedures were performed using a total of 5 mL 1% NaOCl and 5 mL 15% EDTA per canal over 5 min with activation time of 4 × 20 s. Reconstructed data sets were coregistered, and the mean percentage reduction of AHTD after final irrigation was compared statistically between groups using analysis of variance at a significance level set at 5%.

結果:

最終灌流後のAHTDは全群で有意に減少し（P<0.05）、その範囲は44.1％～66.8％であった。灌流後のdebrisのvol%はEAで3.7±1.9%、EDで3.3±2.3%、UAIで2.1±1.6%、MIで4.4±2.3%であり、群間に有意差はなかった（P>0.05）。

RESULTS: A significant reduction of AHTD was achieved after final irrigation in all groups (P < 0.05), ranging from 44.1% to 66.8%. The vol% of debris after irrigation was 3.7 ± 1.9% for EA, 3.3 ± 2.3% for ED, 2.1 ± 1.6% for UAI and 4.4 ± 2.3% for MI, with no significant difference between groups (P > 0.05).

結論:

いずれの最終的な灌流プロトコールも、ヒト下顎骨抜去臼歯の中根管系からAHTDを完全に除去することはできなかった。音波灌流および超音波活性化灌流は、手動灌流と比較して良好な結果を示さなかった。

CONCLUSIONS: None of the final irrigation protocols completely removed AHTD from mesial root canal systems in extracted human mandibular molars. Sonically and ultrasonically activated irrigation performed no better compared to manual irrigation.