电子根尖定位仪临床精确性分析

目的:比较电测法、手感法和拍片法测定根管工作长度的精确性。方法:分别用手感法、拍片法及电子根尖定位仪(electronic apex locator,EAL)Root ZX和Raypex-5在体内测量31个根管的工作长度,与离体直视根尖剖面最狭窄点处测得的根管长度进行比较。结果:Raypex-5准确率为93.55%,Root ZX为87.10%,手感法35.48%,拍片法48.39%。电测法与手感法、拍片法的准确率比较相差非常显著(P<0.01)。结论:电子根尖定位仪测定根管工作长度的准确率比拍片法和手感法高。     

3 种根测仪定位根管侧穿孔准确性的比较研究

目的:比较研究Propex,Raypex 5,Root ZX全自动根管长度测量仪(根测仪)定位根管侧穿孔位置的准确性.方法:选取40 颗离体前磨牙,采用ET40超声工作尖破坏根管中下部根管壁,造成根管侧穿.建立体外模型,使用Propex,Raypex 5,Root ZX全自动根管长度测量仪定位穿孔位置,并比较3 种根管长度测量仪测量准确性.结果:Propex, Raypex 5, Root ZX全自动根管长度定位测量仪测量,均是定位于根管穿孔外壁的位置,并且Propex的准确率为90%, Raypex 5测量准确率为87.5%,Root ZX测量准确率为85%,但3 组准确率的差异无统计学意义(P>0.05). 结论:对于根管壁侧穿的牙齿,使用Propex, Raypex 5,Root ZX全自动根管长度定位测量仪定位的穿孔位置均具有较高的准确性.     

Dentaport ZX测量根管工作长度准确性临床评价

目的：研究Dentaport ZX根尖定位仪测量根管工作长度的准确性。方法：选取129个需进行根管治疗的恒牙为研究对象,插针摄X线牙片计算牙的长度,将电测法和手感法测得的根管工作长度与X线片法测得的根管长度相比较来计算电测法和手感法的准确率,并进行统计学分析。结果：电测法的准确率为89.92％,手感法的准确率为713.2％。结论：电测法的准确率高于手感法,Dentaport ZX根管测量仪使用方便、快捷,能够准确测量根管工作长度。     

Root ZX在老年人后牙不同根管条件下的临床应用

目的:评价Root ZX在老年人牙髓病、根管再治疗中的应用,探讨其适用范围及操作注意事项。方法:随机选取58颗老年人后牙共148个根管作为研究对象,分为2组:A组,活髓牙;B组,根管再治疗牙。均用ProTaper进行根管预备,Root ZX测量预备前后根管工作长度,根管充填术后摄X线片评价准确性,随访2年。结果:A组,有74.7%根管在预备后工作长度超过预备前。B组,预备前后无明显差别。二组X线检查示,恰填率差异有显著性(P<0.01)。2年后治疗有效率89.2%,组间差异无显著性。结论:用Root ZX测量老年人的后牙根管长度,符合解剖生理情况,可以提高测量的准确性,提高治疗成功率。     

两种根管工作长度测量法准确性的临床评价

目的：比较临床常用的X线片指感法与Root ZX测定根管工作长度的准确性。方法：选取临床根管预备后拟作充填的患牙548颗，按就诊顺序分为单、双数两组，分别用X线片指感法和Root ZX电子根管定位仪测定根管工作长度，并依此长度行根管充填、拍X线片，测量根充材料至根尖的距离。结果：Root ZX距根尖1mm内的准确率达94．2％，较X线片指感法（83．8％）高，差异有显著性（P＜0．05）。结论：Root ZX测定根管工作长度准确、简便，建议作为X线片法的辅助工具有临床推广使用。     

三种根尖电子定位仪准确性的体外评价【英】／Martin CL…∥J Endod．

根管工作长度的准确测量是根管治疗成功的重要因素，但不管是手感法还是X线片法都无法准确测量根尖狭窄处的位置。第一、二代的根尖电子定位仪易受其他因素影响而准确率低。本研究评估了三种第三代根尖电子定位仪(EALs)（Justy Ⅱ，Root ZX和Neosono Ultima Ez)的准确性及测量方法的一致性。     

Root ZX根尖定位仪的临床应用评价

目的评价Root ZX根尖定位仪与X线法测定根管工作长度结果的符合性,从而探讨Root ZX根尖定位仪测定根管工作长度的准确性。方法选择临床上共98颗患牙共196个根管为研究对象,Root ZX根尖定位仪测定牙根管工作长度,充分预备后X线片法测牙根管工作长度,两者进行比较并进行统计学分析。结果 Root ZX根尖定位仪测量根管工作长度与X线片法测定的一致率为89.8%,单根和多根牙的结果无显著性差异。结论 Root ZX根尖定位仪测量根管工作长度准确率较高,可作为根管工作长度的常规测量,必要时用X线法校正能进一步提高根管治疗质量。     

根管锉尖直径对Root ZX测量仪准确性影响的研究

目的:研究根管预备时根管锉尖直径对Root ZX根管长度测量仪精确度的影响.方法:40颗正畸减数离体下颌前磨牙,15#不锈钢根管锉测量预备前根管的真实长度.K锉分别根管预备至主锉为40#(常规预备)和60#(过度预备),离体牙植入20 g/L的琼脂生理盐水凝胶巾,15～40#和15～60#K锉分别再次测量预备后根管的工作长度.所有测量值进行方差分析.结果:根管锉尖直径和根管扩大程度对测最仪的准确性有显著性影响(P＜0.05),最大测量值筹别为0.22 mm.结论:根管预备完成后,使用锉尖直径较小的根管锉会使电测根管工作长度变小,根管预备完成后或根充前应选用与根管直径匹配的根管锉再次确认根管工作长度.     

根尖部牙本质碎屑对根长定位仪Root ZX影响的体外实验

目的：通过比较采用Root zx测量离体牙根管预备前后及清除根尖碎屑后的根管长度差异,分析根尖部牙本质碎屑对根长定位仪Root zx测量根管长度准确性的影响。方法：选择根尖孔发育完全的单根管离体牙20颗,于牙颈部截冠、拔髓,在生理盐水琼脂模型上,用15#K锉和Root zx测量根管长度并记录。K锉预备根管至20#、25#、30#,分别用Root zx测量根管长度并记录。去除根尖部牙本质碎屑后,Root zx测量根管长度并记录。统计分析实验数据。结果：根管预备到30#时,多数牙根用Root zx测量的根管长度发生增加,但去除碎屑后,测得的根管长度发生缩短。结论：位于根尖部的牙本质碎屑对Root zx测量根管长度的精确性具有一定影响。     

根管治疗仪测定老年人磨牙根管工作长度准确性的初步研究

目的:初步探讨根管治疗仪在确定老年人磨牙根管工作长度方面的准确性.方法:随机选取须进行根管治疗的老年人磨牙132颗,实验组86颗分为治疗仪组和手感法组,治疗仪组患牙44颗,共131个根管,采用TRIAUTO ZX根管治疗仪确定工作长度,手感法组42颗,共126个根管,采用手感法确定工作长度;对照组46颗为X线片组作为标准组;所有根管预备后插诊断丝摄X线片,比较实验组和标准组测定工作长度的准确率.结果:治疗仪组131个根管中符合工作长度标准的有125个,准确率为95.42%;手感法组126个根管中符合工作长度标准的有103个,准确率为81.75%;标准组146个根管中符合工作长度标准的有139个,准确率为95.21%.X2检验显示,治疗仪组同对照组相比差异无显著性;手感法组同对照组相比差异有显著性.结论:根管治疗仪在老年人根管治疗中,对磨牙根管工作长度的测定方面,比手感法有更高的准确率,与X线片法可取得同样的效果.     

The effects of file size, sodium hypochlorite and blood on the accuracy of Root ZX apex locator in enlarged root canals: an in vitro study

Background : The initial electronic apex locator (EAL) length measurement is generally established with a small‐sized file. It is not known whether file size would be interfering with the reading accuracy of the EAL. This study aimed to evaluate the effect of file size on the accuracy of Root ZX apex locator using an agar model when sodium hypochlorite solution or blood was present during electronic measurements in enlarged root canals. Methods : A total of 36 extracted lower premolars were used. In stage 1, the canals were instrumented using size 10–40 K‐files with a size 40 K‐file as the master apical file (MAF). The teeth were then divided randomly into two groups of 18 teeth each. In group A, the teeth were mounted in one per cent agar and irrigated with six per cent sodium hypochlorite solution (NaOCl), while in group B the teeth were mounted in agar and irrigated with human blood. In stage 2, the canals were enlarged using a size 60 K‐file as the MAF. In stages 1 and 2, the apical portions of the canals were instrumented using the step‐back sequence (up to a size 80 K‐file). In stage 3, the canals were enlarged using a size 80 K‐file as the MAF. In each stage, the length was measured with a Root ZX until the meter value reached ‘APEX’ using small and large size files. Results : Three‐way ANOVA and Bonferroni test showed that file size, stage of preparation and type of irrigant all had a significant influence on the measurement error (P < 0.0001), with all the interactions between these three factors being significant (P < 0.0001). Conclusions : As the diameter of the root canal increased, the measured length with the smaller size files became shorter. A file of a size close to the prepared canal diameter should be used for root length measurement in the presence of blood. In the presence of NaOCl, the Root ZX was highly accurate even when the file was much smaller than the diameter of the canal. The agar model was effective and suitable for testing EALs in vitro.     

Ex vivo evaluation of the ability of four different electronic apex locators to determine the working length in teeth with various foramen diameters

BACKGROUND: The aim of this ex vivo study was to evaluate the accuracy of four electronic apex locators (EALs) to determine the working length in teeth with various foramen diameters. Our previous study revealed that electronically measured canal length was influenced by the root canal diameter. It is not known whether foramen size would interfere with the reading accuracy of an EAL. METHODS: A total of 36 extracted human lower single rooted premolar teeth were divided into four groups of nine teeth each. In groups A, B and C, the root canals were instrumented using #10-80, #10-100 and #10-120 K-files, and the tip of size #80, #100 and #120 K-files were permitted to pass through the apical foramen to a length of 1mm, respectively. In group D, the teeth were instrumented using #10-140 K-files and the tip of #140 K-file was permitted to pass through the apical foramen to a length of 5 mm. Thus, the average apical foramen diameters in groups A, B, C and D were approximately 0.82 mm, 1.02 mm, 1.22mm and 1.5 mm, respectively. The teeth were then mounted in 1% agar and four EALs were used: Root ZX, Foramatron D10, Apex NRG and Apit 7. For electronic measurement, sizes #10 and #80, #10 and #100, #10 and #120, and #10 and #140 K-files were used for groups A, B, C and D, respectively. During electronic measurement the canals were flushed with 6% sodium hypochlorite solution. RESULTS: Three-way ANOVA and Bonferroni test showed that EAL, file size and foramen size all had a significant influence on the measurement error (P<0.0001), with all the interactions between these three factors being significant (P<0.0001). CONCLUSIONS: The four EALs were unreliable to determine the working length of teeth with a wide apical foramen, when using a small size file. The Root ZX and Foramatron D10 showed significantly better scores than the other two EALs and may be more reliable to determine the working length of teeth with a wide apical foramen, if a tight-fit file is used.     

A comparison between two electronic apex locators: an ex vivo investigation

AIM: To compare ex vivo the performance of the Apex Finder and the Root ZX apex locators, with and without irrigant, in canals having different diameters. METHODOLOGY: Sixty canals in 60 teeth were prepared using stainless steel hand files and 0.04 taper NiTi rotary instruments. During preparation the narrowest diameter of the canal was transported to the apical root surface. The canals were irrigated with RC-Prep and 5% NaOCl solution. Six groups were obtained, each with 10 canals having the same diameter of foramen, either 0.15, 0.20, 0.25, 0.40, 0.60 and 0.80 mm. A size 15 K-file was advanced into each canal until its tip was observed under x10 magnification to reach the foramen and the corresponding length recorded. The measurements were performed to an accuracy of 0.25 mm as a base unit of length. The teeth were then fixed to a plastic bar suspended over a glass container filled with 0.9% NaCl solution. Each apex locator was tested when the K-file was at the foramen, or 0.5, 1.0, 1.5 and 2.0 mm short; with the root apex immersed into the solution; with the canal dry or irrigated with NaCl. To evaluate the accuracy of both electronic apex locators (EALs) each electronically determined distance was compared with the actual length and the data analysed using the General Linear Model and the Student t-test. RESULTS: Out of 2400 measurements 100 were electrically unstable, all with the Root ZX. In total, 521 measurements located the position of the file tip beyond the apex, in general, in high conductive conditions with the Root ZX and in low conductive conditions with the Apex Finder. No significant difference in terms of accuracy was found between the two EALs when the file tip was at the foramen (Root ZX mean +0.12 mm, SD 1.22 mm; Apex Finder mean +0.57 mm, SD 1.16 mm). Comparing all the measurements performed with the file tip within 2 mm of the foramen, in all the different conditions tested, the accuracy was affected (P<0.025) by diameter of the foramen, type of EAL, distance to the apex, and by several interactions. CONCLUSIONS: Under the different ex vivo conditions both EALs provided accurate measurements when the file tip was at the foramen. The accuracy of the Apex Finder was negatively influenced by high conductive conditions, whilst the Root ZX provided inaccurate and unstable measurements mostly in low conductive conditions.     

In vitro evaluation of the accuracy of five different electronic apex locators for determining the working length of endodontically retreated teeth

The aim of this study was to evaluate the accuracy of five electronic apex locators (EALs) in determining the working length (WL) of teeth after removal of the root canal obturation materials. A total of 32 extracted straight, single-rooted teeth were used. The actual canal length (AL) was determined and the WL was established by subtracting 0.5 mm from the AL. The root canals were instrumented and divided into two groups. One group (n = 6) served as control, while the other group (n = 26) was the experimental group. In the experimental group, the root canals were obturated using vertically compacted gutta-percha with AH 26 sealer. In both groups, the access cavities were restored with a provisional restoration and stored for 15 days at 37 degrees C and 100% humidity. The root canal obturation material was removed, and the teeth were then mounted in an experimental apparatus. Five EALs were used: Dentaport ZX, ProPex, Foramatron D10, Apex NRG and Apit 7. For the electronic measurement of canal length, a size 25 K-file was used. During measurement, the canal was irrigated with 2.5% sodium hypochlorite. The difference (D) between the AL and the electronically determined length (EDL), AL-EDL, was calculated and recorded for each measurement. Data were analysed by two-way anova and Fisher's PLSD test. In both groups, statistically significant differences were found among the EALs (P < 0.01). In conclusion, the Dentaport ZX, ProPex and Foramatron D10 were more accurate than the other two EALs in determining the WL in teeth after removal of the root canal obturation materials. However, the Apex NRG and Apit 7 were also reliable for determination of the WL in the majority of the cases.     

Electronic length measurement using small and large files in enlarged canals

Electronic apex locators are frequently used attached to a small size endodontic file; however, the effect on the measurement of the relative diameters of the file and the root canal has not been clarified. In this study, the length of enlarged canals was measured using small size files and files matching the canal diameter to observe a possible discrepancy. The accuracy of electronic length control during canal preparation with rotary files was also assessed. The root canals in 21 extracted, single rooted teeth were accessed, and their actual length (AL) established by passing a size 10 file just through the minor apical foramen. The teeth were then embedded in an alginate mold. The initial canal length (IL) was measured with the Root ZX apex locator by negotiating a size 10 file to the apical constriction. The canal was enlarged to size 60 with rotary files while the length was continuously controlled with the apex locator. Then, the final length measurements were obtained with a size 10 file and a size 60 file (FL-10 and FL-60, respectively). The average values of IL, FL-10 and FL-60 were calculated and compared using Repeated Measures Analysis of Variance followed by Tukey's Studentized Range test (P < 0.05). Using composite resin, the size 60 files were secured at the FL-60 length, the teeth were removed from the alginate mold, stained with Picroformal DI Buoin stain and the position of the file tip was observed histomorphometrically after the apical 4 mm of the canal was exposed by grinding the buccal aspect of the root. The IL was 0.45 mm shorter than AL (P < 0.05). The differences between FL-10, FL-60 and IL were not statistically significant. Histomorphometrically, the apical constriction was absent in all the teeth, but the file tips were confined within the root. This study concluded that the Root ZX indicated the location of an apical constriction even when the anatomic constriction was eliminated. In the enlarged canals, length measurements obtained with small and large size files were comparable.     

An in vitro evaluation of the accuracy of Dentaport ZX apex locator in enlarged root canals

BACKGROUND: The aim of this study was to examine the effects of root canal irrigants on the accuracy of Dentaport ZX electronic apex locator (EAL) in enlarged root canals. Our previous study revealed that as the diameter of the root canal increased, the electronically measured length with small size files became shorter in the presence of blood. It is not known whether different canal irrigants would interfere with the reading accuracy of an EAL in enlarged root canals. METHODS: A total of 45 extracted single-rooted human teeth were used. In Stage 1, canals were instrumented using #10-40 K-files with a #40 K-file as the master apical file (MAF). The teeth were randomly divided into five groups and mounted in an experimental apparatus. The following irrigants were used during electronic canal measurements: Group A = 0.5% NaOCl; Group B = 2.5% NaOCl; Group C = 15% EDTA; Group D = 0.8% chlorhexidine (CHX); and Group E = RC Prep. In Stage 2, the canals were enlarged using a #60 K-file as the MAF. In Stages 1 and 2, the apical portion of the canals was instrumented using the step-back sequence (up to a #80 K-file). In Stage 3, the canals were enlarged again using a #80 K-file as the MAF. In each stage, the canal length was measured with a Dentaport ZX using #10 and #40, #10 and #60, and #10 and #80 K-files for Stages 1, 2 and 3, respectively. Data were analysed by two-way ANOVA and Fisher's PLSD test. RESULTS: Statistical analysis showed significant differences among all groups (p < 0.01). There was no significant difference between Group A and B at each stage and between Group D and E at Stage 2. A statistical significant difference was observed between #10 K-file and other files (#40, #60 and #80) at each stage (p < 0.01). In Groups A and B, there was no significant difference between #10 and #40 K-files (Stage 1) and between #10 and #60 K-files (Stage 2). CONCLUSION: The Dentaport ZX was accurate and not adversely affected by the presence of 0.5% or 2.5% NaOCl and EDTA in the enlarged canals, and the measured lengths obtained with small and large size files were comparable. However, it was accurate in the presence of CHX and RC Prep only when large size files were used, and the length measured with small size files was greater than the actual length.     

Accuracy of different electronic apex locators in determination of minimum Root perforation diameter

This study aims to evaluate the ability of Raypex 6, Propex Pixi, Dentaport ZX, Apex ID, Propex II and Dr.'s Finder NEO to detect minimum root canal perforation diameter. One hundred single-rooted, extracted human teeth were artificially perforated by 5 burs in different diameters (0.25–1.25 mm) in 5 mm above the apex. Twenty teeth were assigned to each group. The actual canal lengths (AL) were measured under stereomicroscope followed by a measurement of electronic canal length (EL) using each electronic apex locator (EAL). None of the EALs were able to detect the perforation at diameters of 0.50 and 0.25 mm. Although all EALs used in our study were unable to detect perforations at diameters of 0.5 mm and 0.25 mm, they were highly successful in the determination of simulated root perforations at diameters of 1.25, 1 and 0.75 mm.     

In vivo comparison of working length determination with two electronic apex locators

AIM: To compare the accuracy of two electronic apex locators (EALs) in the same teeth in vivo. METHODOLOGY: The working lengths in 20 teeth with a single canal were determined with two different EALs (Root ZX; J. Morita Corporation, Tokyo, Japan and Raypex 5 VDW, Munich, Germany) before extraction. When the first EAL was used the files were advanced until the display indicated the 'apical constriction'. The files were then fixed in removable and replaceable light curing composite patterns. The procedure was repeated in the same tooth with the second EAL and a different file. The teeth were then extracted and the apical 4 mm of the root canals were exposed. After that the apical parts with the repositioned files in the canals were digitally photographed under a light microscope. On the images the minor diameter and the major foramen of each sample were marked and the respective distances of the file tips from these positions were measured with a computer program. Subsequently the values of the two groups of EALs were compared using a paired sample t-test. RESULTS: The minor foramen was located within the limits of +/-0.5 mm in 75% of the cases with the Root ZX and in 80% of the cases with Raypex 5. The paired sample t-test showed no significant difference between the EALs regarding determination of the minor foramen. CONCLUSION: The use of EALs is a reliable method for determining working length. The differences between the two EALs were not statistically significant.     

Combination of apex locator and endodontic motor for continuous length control during root canal treatment

Aim To compare ex vivo an experimental setup consisting of an electronic apex locator (EAL) and endodontic motor with an established product (Tri Auto ZX) for accuracy of length control during root canal treatment with three different types of files. Methodology An experimental setup consisting of porous spongy material and an electrolyte was used. Sixty anterior teeth were randomly assigned to six groups. Access cavities were prepared. During root canal treatment, constant length monitoring was performed either with the Tri Auto ZX or the Raypex®5 apex locator attached to an endodontic motor (Endo IT professional) using ProTaper, M_two or FlexMaster files. After root canal preparation the distances between file tip and major apical foramen and file tip and minor apical foramen were measured using a microscope and analysed using two‐way anova to evaluate the accuracy of the two systems. Results Distances between the file tip and the major apical foramen were not significantly different between the file systems and the two EALs. In cases treated with FlexMaster significantly larger distances between file tip and minor apical foramen were found compared to M_two and ProTaper. No significant differences were observed between the two EALs. After preparation of the root canals with the Tri Auto ZX, multiple minor apical foramina were mechanically widened. Conclusion With the limitation of this laboratory study the combination of EAL and endodontic motor was as accurate as the Tri Auto ZX system in terms of length control during root canal preparation.