Comparison between Conventional Radiography, Radiovisiography and Raypex 5 Electronic Apexlocator in Determining the Root Canal Length in Posterior Teeth- An Invitro Study

The determination of working length and its maintenance during cleaning and shaping procedures is a key factor for successful endodontic treatment. The aim of this in- vitro study was to evaluate the utility and accuracy of Raypex5 electronic apex locator in determining the working length in comparison to conventional radiography and radiovisiography in posterior teeth. Methods: In this study sixty extracted mandibular first and second molars were used. Diagnostic images were obtained both by conventional radiography and radiovisiography (RVG) and tentative working length was obtained and recorded. After access opening actual root canal length was determined by both conventional radiography and RVG and recorded. Four blinded observers determined the working length in all samples with Raypex5 electronic apex locator. Then at that length file position was checked using RVG. Results: All the data collected was statistically analyzed using one way analysis of variance (ANOVA), Cronbach’s alpha reability analysis and student paired t-test. Conclusion: In this study it was found that Electronic apexlocator Raypex 92 %, RVG 74% and conventional radiograph was 70% accurate in measuring root canal length in posterior teeth.

Significance of vaginal cervical double cerclage for cervical incompetence after pregnancy / 中国基层医药

Objective To observe the pregnancy by transvaginal double slit cervical pregnancy outcome after ligation,and evaluate its clinical application value.Methods The clinical data of 80 cases with cervical incompe-tence were analyzed.All patients had pregnant metaphase inevitable abortion history,the average abortion pregnant was 21.7 week.According to different treatment methods,80 cases were divided into two groups,treatment group (40 cases)in non pregnant women with silk thread woven tape by double vagina and cervix cerclage,another group of 40 cases in 15 -20 weeks of pregnancy by using polypropylene McDonald method with cerclage.The operation,preg-nancy cervical tube length and pregnancy outcome were observed.Results The average operation time and bleeding volume between the two groups had no statistically significant differences.The pregnancy cervical average length of the treatment group was 4.6(4.8 ±0.5)cm,which was significantly longer than 3.9(3.1 ±0.8)cm of the control group (t =2.732,P <0.05).In the treatment group,the full -term delivery rate,preterm delivery rate,mean gestational age at delivery were 55.0%(22 /40),40.0%(16 /40),35.8 weeks,the average abortion was extended 14.1 weeks com-pared with preoperation,fetal survival rate was 90.0%(36 /40),neonatal birth weight was (3 100.0 ±200.0)g;28 gestational weeks following the inevitable abortion rate was 2.5%(1 /40).In the control group,the term delivery rate was 35.0%(14 /40),the rate of premature birth was 50.0%(20 /40),and the rate of abortion was 15.0%(6 /40)in 28 weeks.Mean gestational age at delivery was 33.2 weeks,which was extended 11.5 weeks compared with preoperative average abortion,fetal survival rate was 85.0% (34 /40),neonatal body mass was (2 900.0 ±300.0)g. The term delivery rate,fetal survival rate and neonatal weight in the treatment group were higher than those in the con-trol group.Conclusion Pregnant by double vagina and cervix cerclage treatment cervical function can maintain preg-nancy,cervical length,prolong the time of pregnancy and improve the perinatal survival rate,simple operation,take out stitches convenient,it is worthy of clinical application.

Modelo BRAN-RS para la enseñanza de la conductometría electrónica sin verificación radiográfica a alumnos de licenciatura: estudio piloto / BRAN-RS model for teaching electronic root canal lenght measurement without X-ray confirmation by undergraduate students: a pilot study

Propósito: demostrar la ejecución de la conductometría electrónica sin verificación radiográfica con el modelo BRAN-RS, por dos alumnas de licenciatura en odontología Material y métodos: Se emplearon dos molares naturales, de los cuales se utilizaron seis conductos permeables (cuatro mesiales y dos distales); el localizador de foramen apical Raypex 6, tipodonto de acrílico y alginato. Los dientes se incluyeron en el espacio de los molares, que se abocardó y rellenó con alginato. Se insertó el clip labial por debajo del tipodonto. Una cavidad de acceso fue realizada en cada molar, se determinó la entrada de los conductos y se amplió con fresa Gates-Glidden número 4. Con el dispositivo Raypex conectado, se introdujo gentilmente en cada conducto una lima tipo K número 15 o 20, cerrándose el circuito con el sujetador de limas. La posición de la lima en el foramen se observó en la pantalla, que se indica por medio de la barra y punto rojos. La lima fue reajustada en las dos primeras barras amarillas y se fi jó con resina fotopolimerizable. Los molares fueron retirados del alginato, se diafanizaron y evaluaron con microscopio clínico a 16X para confi rmar la longitud de trabajo. Resultados: La posición de la lima respecto al foramen apical en los seis conductos fue precisa al 100 por ciento. Conclusión: El modelo BRAN-RS es fácil de realizar, preciso, y puede utilizarse por alumnos de la licenciatura en la práctica preclínica de conductometría.

To demonstrate how two undergraduate students perform electronic root canal measurement without X-ray confi rmation using the BRAN-RS model. Material and methods: Six permeable root canals (4 mesial and 2 distal) from two natural molars; Raypex 6 electronic apex locator; acrylic typodont; and alginate. The teeth were inserted in the molar space, which had been widened and fi lled with alginate. The lip clip was placed below the typodont. An access cavity was made in each molar and the entrance to the root canal located and widened using a number 4 Gates-Glidden drill. Once the Raypex device was connected, a number 15 or 20 K-fi le was gently introduced into each canal and the measurement circuit closed using the fi le clip. The posi-tion of the fi le within the foramen was shown on the screen in the form of a red bar and a red dot. The fi le was readjusted within the fi rst two yellow bars and secured using a light-cured resin. The molars were removed from the alginate, then diaphonized and evaluated under a clinical microscope at 16X magnifi cation to confi rm the working length. Results: In the six root canals, the position of the fi le relative to the apical foramen was 100% accurate. Conclusion: The BRAN-RS model is accurate, easy to perform, and can be used by undergraduate students in the preclinical practice of root canal measurement.

Evaluation of electrical impedance ratio measurements in accuracy of electronic apex locators

OBJECTIVES: The aim of this paper was evaluating the ratios of electrical impedance measurements reported in previous studies through a correlation analysis in order to explicit it as the contributing factor to the accuracy of electronic apex locator (EAL). MATERIALS AND METHODS: The literature regarding electrical property measurements of EALs was screened using Medline and Embase. All data acquired were plotted to identify correlations between impedance and log-scaled frequency. The accuracy of the impedance ratio method used to detect the apical constriction (APC) in most EALs was evaluated using linear ramp function fitting. Changes of impedance ratios for various frequencies were evaluated for a variety of file positions. RESULTS: Among the ten papers selected in the search process, the first-order equations between log-scaled frequency and impedance were in the negative direction. When the model for the ratios was assumed to be a linear ramp function, the ratio values decreased if the file went deeper and the average ratio values of the left and right horizontal zones were significantly different in 8 out of 9 studies. The APC was located within the interval of linear relation between the left and right horizontal zones of the linear ramp model. CONCLUSIONS: Using the ratio method, the APC was located within a linear interval. Therefore, using the impedance ratio between electrical impedance measurements at different frequencies was a robust method for detection of the APC.

Evaluation of electrical impedance ratio measurements in accuracy of electronic apex locators

OBJECTIVES: The aim of this paper was evaluating the ratios of electrical impedance measurements reported in previous studies through a correlation analysis in order to explicit it as the contributing factor to the accuracy of electronic apex locator (EAL). MATERIALS AND METHODS: The literature regarding electrical property measurements of EALs was screened using Medline and Embase. All data acquired were plotted to identify correlations between impedance and log-scaled frequency. The accuracy of the impedance ratio method used to detect the apical constriction (APC) in most EALs was evaluated using linear ramp function fitting. Changes of impedance ratios for various frequencies were evaluated for a variety of file positions. RESULTS: Among the ten papers selected in the search process, the first-order equations between log-scaled frequency and impedance were in the negative direction. When the model for the ratios was assumed to be a linear ramp function, the ratio values decreased if the file went deeper and the average ratio values of the left and right horizontal zones were significantly different in 8 out of 9 studies. The APC was located within the interval of linear relation between the left and right horizontal zones of the linear ramp model. CONCLUSIONS: Using the ratio method, the APC was located within a linear interval. Therefore, using the impedance ratio between electrical impedance measurements at different frequencies was a robust method for detection of the APC.

Effectiveness of electronic apex locator during the root canal length in primary teeth: an in vitro study

To evaluate the use of electronic apex locator to measure the root canal length in primary teeth, comparing this measure with the measurements obtained by conventional radiography and by the direct measurement of the root canal lenght.Material and Methods:The sample consisted of nine multi-rooted primary teeth, totaling 32 root canals. Endodontic access was performed with a spherical diamond tip, then the pulp was extirpated and the canal irrigated with 0.9% saline. An endodontic file was used to measure the root canal length by electronic apex locator, using the Novapex ® according to the manufacturer's instructions, and by direct method. An endodontic ruler was used to determine fileÆs length. Conventional radiographic was also performed. Statistical analysis was performed by analysis of variance (ANOVA). The level of significance was 95%.Results:The average of the root canal length was 9.98 ± 2.16 to the direct method; 11.52 ± 1.87 to conventional radiography; and 10.91 ± 1.92 to the electronic apex locator. The results of this study showed a high correlation between the values given by the different methods, regardless of the presence or absence of physiological root resorption. There were not statistically significant differences amongst the methods studied (p> 0.05).Conclusion:Electronic apex locator was an accurate method measure the root canal length in primary teeth, and its use is indicated in endodontic treatment of these teeth...

In Vivo Accuracy of Two Electronic Foramen Locators Based on Different Operation Systems

The aim of this study was to compare in vivo the accuracy of two electronic foramen locators (EFLs) based on different operation systems - Root ZX and Propex II. Ten healthy adult patients needing premolar extractions due to orthodontic reasons participated in the study, providing a sample of 17 noncarious, non-restored, vital teeth (n= 24 canals). After coronal access preparation and cervical preflaring and prior to tooth extraction, the root canal length was measured alternating the two EFLs. All measurements were performed with K-files well fitted to the canal diameter at the level that each EFL indicated the apical foramen in their display (APEX or 0.0). The last K-file were fixed in place with cyanoacrylate, the tooth was extracted, and the apical 4 mm of each root were resected to measure the distance between the file tip and the apical foramen. The mean errors based on the absolute values of discrepancies were 0.30 ± 0.29 mm (Root ZX) and 0.32 ± 0.27 mm (Propex II). Analysis by the Wilcoxon test for paired samples showed no statistically significant differences between the electronic canal measurements performed with the EFLs (p=0.587). The apical foramen was accurately located in 75% (Root ZX) and 66.7% (Propex II) of the cases, considering a ±0.5 mm error margin, with no statistically significant difference by the chi-square test. Despite having different measurement mechanisms, both EFLs were capable of locating the apical foramen with high accuracy in vivo. Under the tested clinical conditions, Root ZX and Propex II displayed similar results.

O presente estudo teve como objetivo avaliar, in vivo, a precisão de dois localizadores eletrônicos foraminais (LEFs) baseados em diferentes mecanismos de funcionamento, Root ZX e Propex II, na determinação do forame apical, sendo utilizados nos mesmos dentes. Após o acesso coronário e o pré-alargamento, e anteriormente à exodontia, os comprimentos de 24 canais radiculares foram determinados eletronicamente alternando-se os dois LEFs. As odontometrias foram realizadas até que os dispositivos apontassem o FA (APEX), utilizando-se limas tipo-K ajustadas. O último instrumento utilizado foi fixado em posição, o dente extraído e os 4,0 mm apicais de cada canal desgastados de forma a possibilitar a determinação da distância entre a ponta dos instrumentos e o forame apical. Os erros médios em função dos valores absolutos das discrepâncias foram, respectivamente, 0,30 ± 0,29 mm (Root ZX) e 0,32 ± 0,27 mm (Propex II). A análise estatística realizada por meio do teste de Wilcoxon para amostras pareadas demonstrou a semelhança entre as determinações do forame apical realizadas pelos dois LEFs (p=0,587). O comprimento radicular até o forame apical foi corretamente determinado em 75% (Root ZX) e 66,7% (Propex II) dos casos, considerando margem de ± 0,5 mm, sem diferenças estatísticas quando analisados pelo teste qui-quadrado. Os LEFs avaliados e consequentemente seus mecanismos de funcionamento, foram capazes de determinar o comprimento dos canais radiculares com precisão em condições in vivo. Nas condições do presente estudo, Root ZX e Propex II apresentaram resultados semelhantes.

A comparative study of the conventional and digital intraoral radiography methods for root canal length measurement / Comparação entre Radiografia intraoral convencional e digital para medição de comprimento do canal radicular: estudo in vitro

Objective: Measurement of root canal length is one of the most important stages of endodentic treatment, and any error at this stage can lead to the failure. This study aimed to compare conventional and digital intraoral radiography in measurement of root canal length. Material and Methods: In this study, 35 single-canal maxillary teeth were collected. Access cavities were prepared. An endodontic number 10#K- file was introduced into the canal, until the tip was visible at the apical foramen and the actual canal length (gold standard) was determined. After acquisition conventional radiographs using E-Ektaspeed and F-Insight film (Eastman-Kodak Co. Rochester, NY, USA) and digital radiographs using Photostimulable Phosphor Plates(PSP) (Soredex, Helsinki, Finland) and Charge Coupled Devices (CCD)(RVG, Trophy,NY,USA). they were examined separately with a two-week interval by two oral and maxillofacial radiologists. The data were analyzed with ANOVA and Tukey’s tests using SPSS-19 software (SPSS Inc., Chicago, IL, USA). Result: No statistically significant difference was observed between different radiographies, and different observers (P > 0.05). Nevertheless, in comparison with the gold standard, in all cases, the F-speed conventional radiography and the digital CCD radiography showed the highest and the lowest accuracy, respectively. Also, the PSP and the E-speed conventional radiography were in the second and third order of accuracy, respectively. Conclusion: The use of digital radiography does not improve the accuracy of the root canal length measurement,but the digital technique has advantages,such as the reduced patient exposure, eliminating the time consuming processing stages, and producing fast images...

Objetivo: A medição do comprimento do canal radicular é uma das etapas mais importantes de tratamento endodôntico, e qualquer erro nesta fase pode levar ao fracasso. Este estudo teve como objetivo comparar a radiografia intra-oral convencional e digital na medida do comprimento do canal radicular.Material e Métodos: Neste estudo, 35 dentes superiores com canal único foram coletados. Cavidades de acesso foram preparadas. Uma lima endodôntica tipo K, número 10 foi introduzida no canal, até que a ponta era visível no forame apical e o comprimento do canal real (padrão ouro) foi determinada. Após a aquisição de radiografias convencionais, utilizando os filmes E-Ektaspeed e F- Insight (Eastman Kodak Co.,Rochester, NY, EUA) e radiografias digitais utilizando placas foto estimuláveis de fósforo (PSP) (Soredex, Helsinki, Finlândia) e dispositivos de acoplamento (CCD) (RVG, Troféu, NY, EUA), as mesmas foram examinadas separadamente com um intervalo de duas semanas, por dois radiologistas oral maxilofaciais. Os dados foram analisados pelos Testes de ANOVA e Tukey utilizando o software SPSS-19 (SPSS Inc., Chicago, IL, EUA). Resultados: Não houve diferença estatisticamente significativa entre as diferentes radiografias, e observadores diferentes (P > 0,05). No entanto, em comparação com o padrão-ouro, em todos os casos, a radiografia convencional e a radiografia digital CCD apresentaram o maior e a menor precisão, respectivamente. Além disso, a PSP e a radiografia convencional estavam na segunda e terceira ordem de precisão, respectivamente. Conclusão: O uso da radiografia digital não melhora a precisão da medição do comprimento de canal, mas a técnica digital tem vantagens, tais como a exposição do paciente reduzida, eliminando o demorado estágio de processamento, produzindo assim, imagens mais rápidas...

Gray scale inversion in digital image for measurement of tooth length

The aim of this study was to assess the applicability of gray scale inversion in performing digital linear endodontic measurements. Standardized digital images were taken of 40 extracted human permanent single-rooted teeth with K-files size 15 placed at different lengths in the root canal, using the CDR Wireless® digital system. All images were treated with Positive, a digital tool that inverts the grayscale value. Eight radiologists measured the distance between the lower limit of the rubber stop and the tip of the file on both original and positive images. After 15 days, they repeated this procedure in 50% of the image samples. The intra- and inter-examiner agreement was analyzed by intraclass correlation test, and the comparison between the two image groups and the actual lengths by the Student's t-test (α=0.05). Intra- and inter-examiner evaluation showed high reproducibility (r>0.95) of both original and positive images. No statistically significant differences (p>0.05) were found between measurements performed on original and positive images, but both differed significantly from the actual lengths (p<0.05). Gray scale inversion has low applicability in measuring endodontic files, since it did not improve the accuracy of measurements.

O objetivo deste estudo foi avaliar a aplicabilidade da inversão da escala de cinza na realização de mensurações endodônticas lineares digitais. Quarenta dentes unirradiculares humanos extraídos foram radiografados com limas K tamanho 15 posicionadas no canal radicular em diferentes comprimentos, usando o sistema digital CDR Wireless®. Todas as imagens foram tratadas com Positive, uma ferramenta digital que inverte os valores da escala de cinza. Oito radiologistas mediram a distância entre o limite inferior do stop de borracha e a ponta da lima endodôntica nas imagens originais e positivas. Após quinze dias, eles repetiram esse procedimento em 50% da amostra. A concordância intra- e interobservador foi analisada pelo teste de correlação intraclasse e a comparação entre os dois grupos de imagem e os valores reais, pelo teste t-Student (α=0,05). A análise intra- e interobservador apresentou elevada reprodutibilidade (r>0,95) das imagens original e Positive. Não foi encontrada diferença (p>0,05) entre as medidas realizadas nas imagens original e positiva, mas ambas diferiram dos valores reais (p<0,05). A inversão da escala de cinza tem baixa aplicabilidade na realização de mensuração endodôntica, considerando que as medidas não se apresentaram mais acuradas.

Comparative analysis of the eletronic and radiographic determination of root canal length of primary molars: an ex vivo study

Aim: To evaluate comparatively the radiographic and electronic root canal length determination in primary molars. Methods: 128 canals from 66 primary molars were selected. The root of each tooth was cut open on the occlusal face, and the real tooth length (RTL) was measured and the gold standard working length (WL) was determined by subtracting 1 mm from this measurement. The teeth were then placed in a plastic receptacle holding alginate and saline for the electronic determination of the root length using a Root ZX apex locator. The radiographic determination of the WL was obtained by subtracting 1 mm from the measurement highest cusp to the root apex appearing in the radiography. The data were analyzed statistically by the Chi-square test at a 5% significance level. Results: There was statistically significant difference (p<0.05) between each tested method and the gold standard. The Root ZX apex locator and the radiographic method presented satisfactory results in 75.78% and 54.68% of the cases, respectively. Conclusions: The Root ZX apex locator is a reliable method to determine the WL of primary teeth, since it showed greater accuracy than the radiographic method.

Análise comparativa ex vivo da eficiência na odontometria de três localizadores apicais eletrônicos: root zx, bingo 1020 e ipex / Comparative analisys ex vivo of the accuracy of three apex locator: root zx, bingo 1020 and ipex

Introdução e Objetivo: O objetivo do presente estudo foi avaliar ex vivo a precisão da leitura de três localizadores apicais eletrônicos: Root ZX, Bingo 1020 e Ipex em relação à medida real dos dentes. Material e métodos: Foram selecionados 50 dentes pré-molares extraídos, unirradiculares. Após abertura coronária, a mensuração do comprimento do dente (CD) foi realizada diretamente pela inserção de uma lima K#10 no canal até que sua ponta fosse observada no forame apical com auxílio de uma lente de aumento (8X). Após a remoção da lima, seu comprimento foi registrado com precisão de 0,01 mm com uso de paquímetro digital. Em seguida, os dentes foram mensurados eletronicamente (CE) com os 3 localizadores apicais até atingir a marca 0 no visor de cada aparelho. As medidas obtidas eletronicamente foram comparadas com o CD e as diferenças analisadas pelo teste de Kruskal-Wallis e pelo teste de proporções (? = 0,05). Resultados: Verificou-se que o sistema Root ZX foi diferente do Ipex (p < 0,01) e o sistema Bingo apresentou resultado intermediário, mostrando-se estatisticamente semelhante aos sistemas Root ZX e Ipex (p > 0,05). Dentro do limite de tolerância de ± 1,0 mm, os resultados demonstraram uma precisão de 100% para o Root ZX, 94% para o Bingo e 90% para o Ipex quando comparados aos valores do CD. Porém, no limite de ± 0,5 mm a precisão obtida foi de 90% para o Root ZX, 68% para o Bingo e de 52% para o Ipex. Conclusão: Todos os dispositivos eletrônicos testados foram hábeis em determinar com precisão o comprimento do dente quando considerada uma variação de 1 mm em relação à posição do forame apical. Porém, quando considerada uma variação de 0,5 mm apenas o aparelho Root ZX mostrou-se preciso.

Introduction and Objective: The objective of this study was to evaluate ex vivo the reading accuracy of three electronic apex locators: Root ZX, Bingo 1020 and Ipex in respect to the real measure of the teeth. Material and methods: Fifty single root premolar teeth extracted were selected. After coronary access, the length tooth (LT) measurement was directly realized by insertion of a K#10 file until its tip was observed in the apical foramen with the help of a magnifying glass (8X). After removing the file, its length was recorded with accuracy of 0.01 mm using digital caliper. Then, the teeth were electronically measured (LE) whit three apex locators until to achieve the zero mark on the display of each unit. The measures electronically obtained were compared with the LT and the differences were analyzed by Kruskal-Wallis Test and Test of proportions (? = 0,05). Results: It was found that the Root ZX system was statistically different from Ipex (p <0.01), the Bingo system presented intermediary result and were statistically similar to the Root ZX and Ipex systems (p> 0.05). Within the limit of tolerance of ± 1.0 mm, the results showed an accuracy of 100% for ZX Root, 94% for Bingo and 90% for Ipex when compared to the LT values. However, in the limits of ± 0.5 mm the accuracy achieved was 90% for Root ZX, 68% for Bingo and 52% for the Ipex. Conclusion: It was concluded that all electronic devices tested were able in determining the precise tooth length when considered a variation of 1 mm from the position of apical foramen. But when considered a variation of 0,5mm only the unit Root ZX proved to be accurate.

Changes in Resonance Frequency and Length of External Auditory Canal in Relation to Age / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: With the currently available diagnostic procedure, hearing impaired children are diagnosed at an early age and hearing aids are fitted soon thereafter. Thus, appropriateness of using available correction methods for adult ears and ear models for determining and predicting hearing aid characteristics for these children need to be examined. The objectives of this study are to create a database of resonance frequency and length of external auditory canal (EAC) in all age groups and to adjust the peak frequency response of hearing aid system to take account of the changing resonance peak frequency as child gets older. MATERIALS AND METHOD: We studied 437 ears with no age limitation. We measured rear ear unaided response (REUR) with Rastronics frequency response analyzer and external ear canal length using silastic tube under microscopic or otoscopic finding. Statistical analyses were performed to determine age differences. RESULTS: Ear canal length increased with age, and an adult value was achieved by the age of 14 years. Resonance frequency decreased with age, and reached to an adult value by the age of 9 years. There was significant relationship between ear canal length and resonance frequency. CONCLUSION: Alteration in resonance frequency with age may have practical implications by affecting the insertion gain of hearing aid system in children. The data may be used as useful adjustment factors to correct the current hearing aid system in children.

An in vitro microscopic study on the accuracy of two kinds of electronic root canal length meter / 实用口腔医学杂志

Objective:To test the accuracy of Tri Auto ZX electronic apex locator(Morita,Japan)and JustyⅡ electronic canal length meter(TME-601,Yoshida Toei Engineering Company,Japan).Methods:26 root canals were tested in vitro.Electronic canal length(L_E) measurements were recorded with Tri Auto ZX and Justy Ⅱ respectively at the reading "APEX" and "0.5".Under stereoscope the deviation of L_E from the actual working length and degree of accuracy were determined.Results:The average deviation of the measurements obtained by Tri Auto ZX was significantly lower than that by JustyⅡat reading"0.5"(P

The accuracy of the radiographic method in root canal length measurement / 대한구강악안면방사선학회지

For the successful endodontic treatment, root canal should be cleaned thoroughly by accurate mechanical and chemical canal preparation and sealed completely with canal filling material without damaging the periapical tissues. The accuracy of the root canal length measurement is a prerequisite for the success of the endodontic treatment, and the root canal length is often determined by the standard periapical radiographs and digital tactile sense. In this study, the accuracy and the clinical usefulness of Digora(R), an intraoral digital imaging processor and the conventional standard radiographs were compared by measuring the length from the top of the file to the root apex. 30 single rooted premolars were invested in a uniformly sized blocks and No.25 K-file was inserted into and fixed in each canal. Each block was placed in equal distance and position to satisfy the principle of the bisecting angle and paralleling techniques and Digora(R) system's image and standard periapical radiographs were taken. Each radiograph was examined by 3 different observers by measuring the length from top of the file to the root apex and each data was compared and analyzed. The results were as follows; 1. In the bisecting angle technique, the average difference between the Digora(R) system and standard periapical radiograph was 0.002 mmand the standard deviation was 0.341 mmwhich showed no statistically significant difference between the two systems(p>0.05). Also, in the paralleling technique, the average difference between these two system was 0.007 mmand the standard deviation was 0.323 mmwhich showed no statistically significant difference between the two systems(p>0.05). 2. In Digora(R) system, the average difference between the bisecting angle and paralleling technique was -0.336 mmand the standard deviation was 0.472 mmwhich showed a statistically significant difference between the two techniques(p 3. In Digora(R) system and the standard periapical radiographs, there was a statistically significant difference between the measurement using the bisecting angle technique and the actual length(p0.05). In conclusion, the determination of the root canal length by using the Digora(R) system can give us as good an image as the standard periapical radiograph and using the paralleling technique instead of the bisecting angle technique can give a measurement closer to the actual canal length, thereby contributing to a successful result. Also, considering the advantages of the digital imaging processor such as decreasing the amount of exposure to the patient, immediate use of the image, magnification of image size, control of the contrast and brightness and the ability of storing the image can give us good reason to replace the standard periapical radiographs.