Evaluation of cutting efficiency of orthograde ultrasonic tips by using a nonstatic model

The purpose of this in vitro study was to evaluate the cutting efficiency of 4 orthograde ultrasonic tips and describe a nonstatic cutting model. Forty molars were extracted and decoronated. Each group contained 10 tips. The samples were fixed to a double pan balance that applied a constant vertical force of 40 g to the ultrasonic tips. The ultrasonic handpiece was mounted to a cyclic axial fatigue testing apparatus to generate a 3-mm horizontal movement of the ultrasonic tip during the cutting procedure. Three cutting cycles of 30 seconds were tested for each power setting of 3, 5, and 7. The weight of the samples was measured before and after the 3 cycles. The cutting efficiency was determined by the weight change caused by dentin removal. The Buc-1 ultrasonic tip had a significantly greater cutting efficiency than the other 3 tips at each of the 3 power settings (P < .05).     

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.     

Comparison of two ultrasonic instruments for post removal

The relative performance of two different ultrasonic units commonly used clinically for post removal was evaluated using tips designed specifically for post vibration. Twenty-four extracted maxillary and mandibular cuspids with crowns removed at the labial cementoenamel junction were treated endodontically. Post spaces were made 10 mm into the roots before cementing a 16 mm #5 (0.050-inch) Para-Post with zinc phosphate cement. The teeth were divided into three similar groups of eight. Post retention was assessed in group 1. Ultrasonic vibration was applied to groups 2 and 3 until post removal. The average force required to dislodge the posts from the teeth in group 1 (control group, no ultrasound) was 40.5 kg (SD = 12.3 kg). The average time for post removal in group 2 (Spartan) was 4:52 min (SD = 2:26). The average time for post removal in group 3 (Enac) was 1:31 min (SD = 0:34). The difference between groups 2 and 3 was statistically significant (p < 0.005). Use of ultrasonic tips designed for post vibration and maximization of audible sound level during ultrasonic treatment of posts seem to play an important role in the effectiveness and efficiency of post removal. The results obtained indicate that both the Enac ultrasonic unit with the ST-09 vibration tip and the Spartan ultrasonic unit with the Analytic VT-S tip were effective. Nevertheless, the Enac ultrasonic unit with the ST-09 vibration tip was clearly more efficient under these study conditions, resulting in typical post removal times of <2 min.     

Evaluation of the efficiency of a new file removal system in comparison with two conventional systems

A novel file-removal system (FRS) was designed to address weak points of conventional file-removal methods. The purpose of this study was to compare file-removal time and dentin removal rates among the FRS, the Masserann kit (Micro-Mega, Besancon, France), and an ultrasonic file-removal method. Ninety extracted mandibular incisors with separated nickel titanium files were divided into 3 groups of 30 teeth each. Groups 1, 2, and 3 had file-removal attempts made by using the Masserann kit, a CPR-7 titanium ultrasonic tip (Obtura-Spartan Corp., Fenton, MO), and the FRS, respectively. Each group had three operators removing the separated files. Pre-/postoperative digital radiographs were downloaded into image analyzing software that calculated the amount of dentin removed. The FRS needed less time and had less dentin loss than the others (p<0.05). There were statistical differences between the experienced operator and less experienced operators regarding the file-removal time and the dentin removal rates (p<0.05).     

超声工作尖切削根管壁时根面温度变化的研究

目的 评价超声工作尖不同方式作用于根管内壁对根面温度变化的影响。方法 使用ET40超声工作尖分别在两种功率下和有水或无水冲洗两种状态下作用于8颗离体牙的根管内壁，热电偶测温仪测量其根面温度变化。结果 超声作用于根管内壁时会导致根面明显升温。功率大小对根面温度上升的影响显著，水能起到明显的降温作用。结论 临床应避免使用高功率长时间切削牙本质。     

A novel methodology to evaluate the use of an ultrasonic tip

Introduction

The purpose of this in vitro investigation was to use a novel methodology to evaluate the use of an endodontic ultrasonic (US) tip.

Methods

BUC 1 US tips (n = 10) were mounted to a testing apparatus that applied a linear movement of the US tip to dentin specimens with an axial force of 15 g. Instrumentation was activated for 20-second cycles up to a 2-minute baseline and continued for 10-minute intervals up to a defined inefficient/dropout point. Dentin cutting efficiency was measured by the change in weight of dentin specimens to the nearest 0.01 mg. A quantitative analysis was conducted on length and diameter of the US tips by using images taken at 15.625 magnification and 1000 pixels/cm (1 pixel = 0.01 mm) resolution. Weight of dentin specimens and images were captured at 2, 50, 100, 150, and 190 minutes of instrumentation.

Results

There was no statistically significant difference in dentin removal between measurement times for any US tip specimen. There was a statistically significant difference in tip length over time (P = .002). Tukey post hoc analysis revealed that tip length decreased significantly at 2 minutes of instrumentation.

Conclusions

Within the limits of this investigation, the BUC 1 US tip did not significantly decrease in efficiency between 2 and 190 minutes of use. The decrease in tip length was found to be significant at 2 minutes of instrumentation. Adding a linear movement, in addition to an axial force, for testing US tips will make future investigations more clinically relevant.     

Efficiency of a Newly Designed Ultrasonic Unit and Tips in Reducing Temperature Rise on Root Surface During the Removal of Fractured Files

IntroductionA potentially damaging temperature rise within the root canal and thus on the external root surface may be induced because of frictional contact of ultrasonic tips during the removal of separated instruments. The efficiency of a new ultrasonic unit, with air-spray function and ET40D (Satelec/Acteon, Merignac, France) and CPR5 (Obtura-Spartan, Fenton, MO) ultrasonic tips, in reducing temperature rise on the external root surface during the removal of fractured files was investigated.MethodsFour millimeters of F2 ProTaper files (Dentsply, Surrey, UK) were fractured 2.5 mm from the canal access of 60 lower incisor roots. Roots were randomly divided into six groups: groups CPR5/no air and ET40D/no air in which tips were used without air flow, groups CPR5/15 psi and ET40D/15 psi (tips used with 15-psi air pressure), and groups CPR5/10 psi and ET40D/10 psi (10-psi air pressure). The temperature rise was measured on the external proximal root surface, adjacent to the most coronal aspect of the fractured fragment, at 15 seconds and then at 30-second intervals up to 120 seconds.ResultsAfter 120 seconds, the mean temperature rise (4.2°C) with the air flow active was significantly lower than that with nonactive air flow (11°C). At 10- and 15-psi pressures, the temperature rise after 120 seconds induced by ET40D tips was 4° and 2.4°C, respectively. These were significantly lower than with CPR5 tips (6.3° and 4.2°C, respectively).ConclusionsA new ultrasonic unit incorporating an air-flow function proved to be effective in reducing the temperature rise during removal of fractured files. ET40D ultrasonic tips were more effective than the CPR5 tip. However, both tips could be safely activated with air spray up to 120 seconds.     

Vibration characteristics of ultrasonic scalers assessed with scanning laser vibrometry

OBJECTIVES: Scanning laser vibrometry is a non-invasive method of accurately measuring the vibratory characteristics of oscillating objects. The aim of this study was to observe, using a scanning laser vibrometer (SLV), the vibration patterns of dental ultrasonic scaler tips and to assess the effects of water flow rate and power setting on these patterns whilst operating the tips in an unloaded environment. METHODS: A 30kHz ultrasonic scaler (TFI-10, Dentsply) was fixed in position and a laser beam from the SLV was focused onto the tip. The laser, guided by a virtual measurement grid, was scanned over the oscillating tip surface. Scans were taken with the laser beam perpendicular to the long axis of the front face of the tip. RESULTS: Oscillation frequencies and the displacement amplitude at the unconstrained end of the tip were measured for various power/water settings. Vibration nodal positions were recorded for the various settings and were found to occur approximately 4mm from the free end of the tip. At low and medium power settings, tip displacement amplitude was reduced by increased water flow. At high power settings, combined with a high flow rate, the water leaves the body of the instrument as a jet. This left the tip relatively unconstrained, allowing it to oscillate at increased displacement amplitudes. CONCLUSIONS: This study shows that the SLV is able to accurately characterise the movement of oscillating ultrasonic scaler tips. The tips are affected by power setting and water flow rates.     

Cleaning ability and induced dentin loss of a magnetostrictive ultrasonic instrument at different power settings

Some laboratory studies have evaluated the oscillation mode of ultrasonic scalers. None of them recorded its influence on calculus removal and quantified dental hard tissue loss. This study aimed to compare the performance of a magnetostrictive ultrasonic instrument at different power settings in vitro in relation to the tip oscillation activity. The oscillation activity of the straight Slimline® insert in the Cavitron® ultrasonic scaling device was analyzed at five different power settings with the help of two laser vibrometers. The performance of this instrument was tested on 60 roots of human single-rooted teeth. Twelve roots each were randomly assigned to be instrumented at a given power setting. Every root was instrumented for 120 s at a standardized instrumentation force of 0.1?±?0.05 N. In addition, another 30 periodontally involved roots with subgingival calculus were instrumented accordingly to assess the calculus removal potential. The surface characteristics after instrumentation were analyzed under scanning electron microscope. The instrumentation at minimum power setting resulted in an mean increase of the root surface roughness of 0.18?±?0.28 compared to 0.51?±?0.48 at maximum power setting (P?=?0.0327). The loss of dental hard tissue amounted to 11.37?±?3.64 at minimum compared to 23.37?±?15.76 at maximum power (P?=?0.0010). The higher the power setting, the more calculus was removed. The values of the latter ranged between 4.04?±?1.87 and 11.26?±?4.66 mm² of cleaned dentin surface area (P?=?0.0065). At lower power settings, a more favorable relation between cleaning ability, loss of dentine, and surface roughness was found.     

Water coolant supply in relation to different ultrasonic scaler systems, tips and coolant settings

Objective: This study evaluated "in vitro" the consistency of the water coolant supply for five ultrasonic scaler systems in relation to the tip type and different coolant settings.
Material and Methods: The systems were: EMS PM-400, EMS PM-600, Satelec P-max, Dürr Vector and Dentsply Cavitron. For each system, three units were used and on each unit various tips were tested. The tips were run unloaded for 1 min. at full and medium water supply setting.
Results: At full water coolant setting, the PM-400, PM-600 and Cavitron supplied on average >45 ml/min. of water coolant (51.5, 46.3 and 46.9 ml/min., respectively). The P-max supplied 25 ml/min. and the Vector supplied 4.9 ml/min. At medium setting, the PM-400 and PM-600 supplied approximately 50% of the volume given at the full coolant setting (25.0 and 26.3 ml/min., respectively). The Cavitron supplied approximately 40% at medium setting (18.2 ml/min.) and the P-max supplied approximately 25% (5.7 ml/min.).
Conclusion: The coolant control system of the different units did not provide a reliable indication of the water flow. Also, some perio tips gave less water coolant as compared with other tips of the same brand. Consequently, a change of tips during treatment may require adjustment of the water coolant supply.     

Evaluation of cutting efficiency of ultrasonic tips used in orthograde endodontic treatment

The purpose of the present study was to evaluate the cutting efficiency of the three different ultrasonic tips for orthograde endodontic treatment: stainless steel, zirconium nitride-coated, and diamond-coated tips. An ultrasonic handpiece was mounted on a custom-made automated balance, and each tip repeatedly penetrated dental stone blocks to a depth of 3 mm for 10 times. The amount of time taken to penetrate 3 mm of stone was measured. The diamond-coated tips showed significantly greater cutting efficiency than either stainless steel tips or zirconium-nitride coated tips. The stainless steel tips showed initial better cutting efficiency, but over time , there is no significant difference between the cutting efficiency of the stainless steel tips and the zirconium nitride coated tips. The diamond coated tips were the only group that showed breakage in this study.     

Influence of cutting instruments and adhesive systems on hybrid layer formation

Influence of cutting instruments and The aim of this study was to analyze the hybrid layer in noncarious dentin prepared by different cutting instruments and restored with composite resin. The cavities were randomly prepared in 40 specimens using a high-speed diamond bur (KG Sorensen 1013) and an ultrasonic tip (CVDentus C22). The cavities were restored with composite resin by varying the adhesive system between the Adper? Single Bond (2 x 1 system, primer+adhesive) and the Prompt L-Pop? (3 x 1 system, self-etching). The restorations were hemisected longitudinally and analyzed in the SEM (Scanning electron microscopy) in order to evaluate the hybrid layer and resinous tags characteristics, using scores ranging from 1 to 6. The Pearson test revealed a high correlation coefficient and good significance levels for both intra- and inter-raters values (r=0.90). The data were statistically analyzed using the Mann-Whitney test (P≤0.05). A larger proportion of regular hybrid layers with numerous tags were observed in the dentin prepared using the high-speed diamond burs and restored with a 2 × 1 adhesive system. Alternatively, the 3 × 1 adhesive system promoted the generation of a thin hybrid layer with few tags. After preparation using an ultrasonic tip revealed few or no tags after the preparation and 2 × 1 or 3 × 1 adhesive system application. The high-speed diamond burs produced a dentin surface that was more favorable to restorative material adhesion than the ultrasonic tips, regardless of the adhesive system used.     

Comparison of two ultrasonic units in shaping simulated curved canals

The effects of ultrasonic instrumentation on the preparation shape of curved simulated canals were investigated. Measurements of the displacement amplitudes of the files were made to examine the possible relationship between displacement amplitude and the cutting ability of the file. Twenty-five simulated canals in clear resin blocks were instrumented using a Cavi-Endo unit at a power setting of 1 with differing times of instrumentation and with water as irrigant. Another group of 25 canals received similar treatment but were instrumented with an Enac unit at a power setting of 1. The canal shape and the incidence of elbow formation were evaluated using various measurements taken from photographic prints of the canals. All canals exhibited unequal removal along the canal with more removal occurring coronally. The Enac group exhibited a higher incidence of elbows which occurred further apically than those in the Cavi-Endo group. There was no significant difference between groups in the amount of apical canal enlargement. Coronally, the Enac appeared to cut significantly better. The Enac also caused significantly greater apical deviation and change in width. In both units more elbows were formed following instrumentation, with less flexible files having smaller displacement amplitudes.     

Dental plaque removal by cavitational activity during ultrasonic scaling

Photomicrographs of the surfaces of recently extracted teeth stained with erythrosin dye were obtained. The stained surfaces were treated with an ultrasonic scaler using two different types of scaling tips driven by the same instrument operated at a medium power setting. Small areas of stained plaque removal occurred when the stationary scaling tip was operated without water cooling. Additional areas of removal were observed where a water coolant was present, which were larger than those produced by the non-water cooled tip. These additional areas were influenced by the type of scaling tip used, it's orientation to the tooth surface and it's displacement amplitude. Cavitational activity in the cooling water supply of the ultrasonic scaler is able to remove dental plaque from tooth surfaces and may be a useful adjunct to the mechanical action of the instrument.     

超声冲洗在根管治疗术中应用

超声冲洗在根管治疗术中的应用越来越多。超声工作尖震动使冲洗剂产生空穴作用和声流作用,所产生的剪切力可清除根管壁上的牙本质碎屑及生物物质。镍钛工作尖能更好地顺应根管解剖形态。工作尖为光滑或K锉形态对牙本质碎屑和玷污层的清洁效果无明显区别。超声冲洗能更好地清除根管内的细菌、玷污层和牙本质碎屑等,并对根管内的复杂结构有更强的清洁效果。超声冲洗选用次氯酸钠为冲洗剂可取得良好效果。冲洗液的使用量较其浓度更为重要,间断冲洗比连续冲洗更有效。超声工作尖插入的方向和深度亦会对冲洗效果产生影响。现从超声冲洗的作用机制、仪器设备、冲洗效果和影响因素等方面做一总结,以指导临床实践。     

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??Ultrasonic irrigation has been increasingly used in root canal therapy. The oscillating ultrasonic tips can induce cavitation and acoustic streaming??which can produce shear stress along the root canal wall and remove debris and bacteria. Nickel-titanium tips can adjust the anatomic modality of root canal preferably. There is no significant difference between a smooth wire and a cutting K-file as the ultrasonic tip on the removal of dentine debris and smear layer. Passive ultrasonic irrigation??PUI??removes more bacteria??smear layer and dentine debris and is an important supplement for cleaning complicated root canal system. Irrigation with sodium hypochlorite is effective. The use volume of irrigation is more important than density. PUI with a pulsation pattern is more effective in removing dentine debris than a continuous oscillation. The insertion direction and depth of the ultrasonic tip are affective. In this paper the mechanism of action??instrumentation??efficiency and relevant factors of PUI were reviewed in order to guide the practical application.     

Temperature rise produced by different light-curing units through dentin

AIM: This study investigated the temperature rise caused by different light curing units and the temperature increase in dentin of different thicknesses. METHODS AND MATERIALS: Dentin discs of 1.0 and 2.0 mm thicknesses were prepared from extracted human mandibular molars. Temperatures were recorded directly at the surface of the light guide tip, under dentin discs with different thicknesses, and through a sandwich composed of 2 mm thick cured composite and dentin using a K-type thermocouple. The curing units used were two quartz-tungsten-halogen lights (Spectrum and Elipar Trilight-ET) and a light-emitting diode (LED). RESULTS: The highest temperature rise was observed under a Mylar strip using ET standard mode. Under 1 and 2 mm thick dentin barriers, the lowest temperature rise was measured for the LED curing light. Significant differences in temperature rise existed among all curing units except between the Spectrum and ET exponential modes under a 1 mm thick dentin barrier with cured composite. Temperature rises were insignificant between the Spectrum and ET exponential modes and between two modes of Trilight when the same experimental setup was used under a 2 mm thick dentin barrier. CONCLUSION: For all curing units, temperature elevation through 2 mm of dentin was less than for 1 mm of dentin thickness. The ET standard mode produced the highest and the LED produced the lowest temperature rise for all tested conditions. The thickness of dentin and light-curing unit might affect temperature transmission.     

An in vitro investigation into the cutting action of ultrasonic radicular access preparation instruments

The aim of this study was to investigate the dentine cutting action of a CT4 and SJ4 radicular preparation inserts (Excellence in Endodontics/Analytic Technology, Orange, CA, USA) used in a Piezon Master 400 ultrasonic handpiece (Electro Medical Systems SA, Nyon, Switzerland). Calibration of the ultrasonic inserts was carried out at minimum, medium and maximum power settings using light microscopic measurement of the tip displacement amplitudes (x120 mag). Polished dentine samples were instrumented, at monitored loads, at the three chosen power settings, to produce uniform dentine cuts. The resultant dentine debris was collected for SEM analysis, and comparison with that produced by rotary instruments. The depth of dentine cut was measured at x30 magnification. Fracture of the SJ4 insert was noted at medium power setting. Results revealed a significant increase in both displacement amplitude and depth of dentine cut with power setting (ANOVA P < 0.001). Dentine chip size increased with power, and differed in structure and appearance from those produced by rotary instruments. In conclusion, ultrasonic cutting is influenced significantly by power setting, and dentine chip formation is fundamentally different to rotary instrumentation.     

An in vitro investigation into the cutting action of ultrasonic radicular access preparation instruments

Abstract – The aim of this study was to investigate the dentine cutting action of a CT4 and SJ4 radicular preparation inserts (Excellence in Endodontics/Analytic Technology, Orange, CA, USA) used in a Piezon Master 400 ultrasonic handpiece (Electro Medical Systems SA, Nyon, Switzerland). Calibration of the ultrasonic inserts was carried out at minimum, medium and maximum power settings using light microscopic measurement of the tip displacement amplitudes (×120 mag). Polished dentine samples were instrumented, at monitored loads, at the three chosen power settings, to produce uniform dentine cuts. The resultant dentine debris was collected for SEM analysis, and comparison with that produced by rotary instruments. The depth of dentine cut was measured at ×30 magnification. Fracture of the SJ4 insert was noted at medium power setting. Results revealed a significant increase in both displacement amplitude and depth of dentine cut with power setting (ANOVA P <0.001). Dentine chip size increased with power, and differed in structure and appearance from those produced by rotary instruments. In conclusion, ultrasonic cutting is influenced significantly by power setting, and dentine chip formation is fundamentally different to rotary instrumentation.     

Significant influence of scaler tip design on root substance loss resulting from ultrasonic scaling: a laserprofilometric in vitro study

OBJECTIVES: Ultrasonic scalers have become increasingly popular for subgingival debridement. The aim of the present study was to investigate the influence of different working tip designs (narrow versus wide) on root substance loss caused by either magnetostrictive or piezoelectric ultrasonic devices. METHODS: In this in vitro study, a magnetostrictive ultrasonic system with either Slimline or TFI-10 inserts and a piezoelectric ultrasonic system with either Perioprobe or Type-A inserts were compared at different application forces. Loss of root dentin was determined by defect width, defect depth and defect volume resulting from standardized instrumentation using laser profilometry. RESULTS: There were consistent and statistically significant differences between all groups. The mean observed dentin alterations for the magnetostrictive ultrasonic device operating a Slimline insert at a lateral force of 0.3 N were 254.4 microm, 6.3 microm and 22.5 microm3 and for the TFI-10 tip 759.0 microm, 23.5 microm and 160.2 microm3 for the parameters defect width, depth and volume, respectively. For the piezoelectric ultrasonic system operating a Perioprobe insert, the corresponding mean values were 352.0 microm/12.1 microm/56.4 microm3 and for the universal Type-A insert they were 402.4 microm/14.0 microm/133.4 microm3. With application forces of 0.7 N, root substance removal increased up to twofold. CONCLUSION: The present investigation could demonstrate that the aggressiveness of magnetostrictive and piezoelectric ultrasonic devices to root substance was significantly influenced by the scaler tip designs, increasing for wider scaler tips as compared with narrow, probe-shaped inserts.