ObjectiveThis study aims to compare the efficiency of three kinds of microtube extraction devices, namely, instrument removal system (IRS), micro-retrieve and repair (MR&R) system, and MR&R system using modified microtube in removing separated instruments with different exposure lengths.MethodsAfter a cross-section platform model was established, the IRS, MR&R, and MR&R modified microtube system with sidewall window reduced to 0.20 mm were used to retrieve various separated instrument models, and the differences in extraction effects were statistically analyzed by Chi-square test. The separated instrument models were divided into two groups: stainless steel and nickel-titanium instrument groups. In total, 23 instruments were tested for three times each.ResultsWhen the exposed length of separated instrument was 0.50 mm, the removal efficiency of the modified MR&R system group was significantly higher than those of the IRS and MR&R system groups (P<0 .001). when the broken end of the fracture instrument was up to 1.00 mm, the success rates of the mr&r system and modified mr&r groups were significantly higher than that of the irs group (P<0 .01). no difference was observed among these three devices when the exposure length of separated instruments was 1.50 mm or higher.ConclusionThe MR&R and modified MR&R systems have good removal effect when the exposed length of separated instrument is small.
