声波与超声波器械配合不同冲洗液对根管清理效果的扫描电镜研究

目的：比较声波与超声波根管器械配合不同冲洗液预备根管的清理效果。方法：制作根管扫描电镜标本，观察根管玷污层分布和牙本质小管暴露情况，各标本的冠1／3、中1／3、根尖1／3区域各取10个500倍视野照相，分级评分(玷污层分数，SL)。统计学分析比较三种冲洗液条件下声波和超声波器械根管清理的差异。结果：仅以蒸馏水作冲洗液，声波不能有效清理碎屑与玷污层；25g／L NaClO冲洗，根尖1／3玷污层的去除超声组优于声波组，但未清除玷污层栓层；25g／L NaClO结合170g／L EDTA作冲洗液，玷污层去除显著且两组无显著差异，但根尖1／3差于根管中上段，超声组部分区域牙本质小管蚀刻与融合。结论：声波结合25g／L NaClO和170g／L EDTA可有效去除玷污层并达到与超声器械近似的根管清理效果，根管内荡洗去除玷污层栓层效果显著，且未对根管壁产生破坏，但有必要加强根尖部荡洗。     

Effectiveness and safety of a sonic vibratory endodontic instrument

Abstract An air-driven sonic vibratory handpiece to which specially designed K-type files are attached has been developed. When activated, the root canal instruments will vibrate in a whirling motion, and when moved up and down, will abrade the root canal wall. The sonic system was tested in simulated root canals in plastic blocks and in usage tests in dogs' teeth. Forty-nine roots in 3 dogs were divided into 3 groups. Two of the groups were instrumented with the sonic device under continuous irrigation with 2.5% NaOCl or 15% EDTA. The 3rd group was treated with conventional chemomechanical instrumentation and 2.5% NaOGl. The teeth were then extracted, fixed and split in a longitudinal direction and the root canals examined in the scanning electron microscope. After hand instrumentation and sonic instrumentation using NaOCl for irrigation, the canal wall was covered by a smear layer and dentin chips and occasional tissue remnants were seen. An extraoral fine mist of NaOCl was seen during continuous irrigation with this medicament, causing eye soreness in the operator. Continuous irrigation with EDTA during sonic instrumentation removed the smear layer and gave clean canal walls. The vibratory files appeared safe and size 20 followed curved canals well. The effectiveness of the sonic device was similar to hand instrumentation. It considerably improved the ease and, to some extent, the speed of root canal instrumentation.     

Clinical suitability of a sonic vibratory endodontic instrument

Abstract A sonic vibratory device with the shape, size and weight of a dental handpiece has been developed for the instrumentation of root canals. Specially designed K-type files are used with the handpiece, which is air-driven and may be attached to the high-speed air line of a dental unit. A clinical study was performed using conventional hand instruments and the sonic system in the instrumentation of root canals. Also studied was the use of continuous irrigation of the root canal with EDTA and filtered tap water with the sonic device. Instrumentation time, procedural and clinical complications, as well as overall suitability of the new device were evaluated. The results indicated that the sonic vibratory system was well-suited for root canal instrumentation. The vibratory files appeared safe and complications were well within acceptable limits. Irrigation with a continuous flow of EDTA was not acceptable, mainly because of crystallization and clogging of tubes and handpieces. Filtered tap water was well-tolerated and its cleaning effect was good. The sonic device could be used with ease and resulted in decreased operator fatigue when compared with hand instrumentation.     

Cutting characteristics of a sonic root-end preparation instrument

Abstract The aim of this study was to investigate the culling ability of retro tips powered by a sonic handpiece (MM 1500, Micro Mega, Prodonta, Geneva, Switzerland). Two levels of the following variables were evaluated in this study: a) power selling with the air inlet ring half or fully open, b) orientation of lip perpendicular or parallel to the long axis of the handpiece, c) length of tip 2 or 3 mm, d) loading of 25 or 50 grams, e) tip size 35 or 55. The substrate used was 1 mm thick set lions of bovine bone and load was controlled by using a load cell interfaced with a transducer meter. Instrumentation time was fixed at 10 seconds with water irrigation. A 2⁵ full factorial analysis was performed with two replications making a total of 64 experimental units. The resultant depth of cm was measured using a stereo microscope at x50 magnification. Analysis of the data indicated that all variables had a significant effect on cutting (ANOVA p<0.05). The most significant factor was power, followed by tip length, tip orientation, width and load. An increase in loading resulted in tip constraint and a reduction of culling at the lower power selling. In conclusion sonic ally activated retro tips were found to cut satisfactorily with instrument air inlet ring opening/power having the main effect.     

Cutting characteristics of ultrasonic surgical instruments

Objective: Ultrasonic surgical devices are becoming increasingly popular and work is required to understand the performance of the cutting tips. This experimental study looks to investigate the way in which ultrasonic bone cutting tools oscillate and how this oscillation is modified when contacted against bone surfaces with varying loads. The defects produced in instrumented bone surfaces were measured and related to the tip motion. Methods: An ultrasonic cutting probe was scanned, unloaded, using a scanning laser vibrometer to determine its free oscillation pattern and amplitude. This probe tip was then contacted against bone under various loads to assess the modification in oscillation characteristics. Cuts were performed over a period of 10 s. The cut bone surfaces were assessed using laser profilometry to determine defect depths. Results: The average vibration displacement amplitude at the probe tip, under load, was <12 μm in the longitudinal direction and was greatest for the cortical cutting mode. Elliptical probe motion was successfully mapped out under the range of loads tested. Defect depths of up to 0.36 mm were detected and were greatest when the tip was in contact with the bone with a load of 100 g. Conclusions: This work showed that the nature of the surface being cut may significantly alter the mode shape and magnitude of the probe oscillation. The maximum depth of cut with minimum restraining of tip motion was achieved at 100 g contact load. To cite this article:
Parmar D, Mann M, Walmsley AD, Lea SC. Cutting characteristics of ultrasonic surgical instruments.
Clin. Oral Impl. Res. xx , 2011; 000–000.
doi: 10.1111/j.1600‐0501.2010.02121.x     

Case report: removal of fractured endodontic posts with a sonic instrument

Fracture of endodontic posts within the root canal system is one of the causes of failure to restore endodontically treated teeth. Various techniques, with varying degrees of success, have been proposed in the literature for the removal of fractured posts prior to re-restoring the tooth. This case report describes the use of a sonic device to dislodge and remove two fractured prefabricated metal endodontic posts from teeth UR1 and UL2. The reader is also introduced to a variety of post removal techniques available.     

Comparative in vitro studies of sonic, ultrasonic and reciprocating scaling instruments

Flat root surface areas of formalin-stored mandibular incisors with plaque and calculus were scaled by sonic (PHATELUS SONIC SCALER, SONIC FLEX 2000, TITAN-S SONIC SCALER) or ultrasonic instruments (HYGIENIST ULTRASONIC SCALER, CAVITRON) or by a new reciprocating scaling insert for the EVA/PROFIN system. The test areas were photographed by SEM and coded micrographs were independently graded by three examiners using the RCI (Remaining Calculus Index) and the RLTSI (Roughness Loss of Tooth Substance Index). The findings revealed that the sonic scalers as a group removed calculus more completely but also left significantly more roughness and loss of tooth substance than the other instruments tested. No difference was seen between the two ultrasonic scalers. The reciprocating insert gave results similar to those of the ultrasonic except for the scaling time which was significantly longer for the new "cleansing principle".     

Cutting ability of an ultrasonic retrograde cavity preparation instrument

Abstract The aim of this study was to investigate the cutting ability of a working ultrasonic instrument designed for surgical endodontic use (Neosonic, Amadent Corp, Cherry Hill, NJ, USA). Three designs of tip, designated CT 1 to CT 3 were calibrated by measuring their displacement amplitudes in air using light microscopy over a range of power settings. Extracted teeth were sectioned longitudinally and polished to produce a smooth dentine surface onto which the tips were applied for 1 minute over the above range of power settings at a load of approximately 20 g. The depth of cut in the dentine surface was measured using a two dimensional surface profilometry technique. Results showed that a raising of the power setting produced an increase in displacement amplitude and cutting ability for all tip designs. This increase was linear, with minimal cutting occurring at lower power settings. In conclusion the ultrasonic tips could be successfully used to remove dentine, and medium to high power settings optimised their efficiency.     

牙体牙髓临床治疗Ⅳ.镍钛合金根管器械折断的临床特点及防治

镍钛合金根管器械预备弯曲根管的效果理想,已在国内外得到广泛使用.但临床上镍钛合金根管器械折断前往往无任何征兆,手用镍钛器械切割效率较不锈钢器械低,预备时需较大力量,易嵌入根管造成器械折断;而机用根管器械预备时因缺乏手感较手用镍钛器械折断几率更高.器械折断会影响治疗效果,还会影响医师在治疗中的信心.本文将重点讨论镍钛合金根管器械折断的分类、与折断相关的因素及防治措施.     

Taper and stiffness of sonic endodontic files

Abstract The aims of this investigation were to measure the thickness and taper of the different files (Heliosonic 15–40, Shaper 15–40 and Rispisonic 1–6 supplied with the MM 1500 sonic instrument and relate this to their stiffness. The diameter of the files (n = 5 for each file type) was measured at 2 mm intervals using light microscopy and a calibrated graticule (mag × 120). A model system was developed for the stillness testing. The file was held 3mm from its tip and the load in g required to produce a 45° deflection of the file was recorded. Measurements of file diameter showed that the width of the Heliosonic and Shaper increased in a linear manner and that the file taper was the same for increasing file sizes in accordance with ISO recommendations. The Rispisonic files however showed differing widths and degrees of taper which were not consistent with ISO standards. The stiffness testing results showed the I Heliosonic files to be less flexible than the Rispisonic and Shaper files for all sizes (ANOVA, p < 0.001). The differences in stiffness of the Heliosonic, Shaper and Rispisonic files were due to the variation in cross sectional area of metal. In conclusion sonic endodontic files do not have the same taper and stiffness.