|Year : 2016 | Volume
| Issue : 2 | Page : 37-40
In vitro evaluation of the accuracy of ProPex II, Raypex 6 and iPex II electronic apex locators in primary molar teeth
Levent Demiriz1, Mustafa Murat Kocak2, Baran Can Saglam2, Sibel Kocak2
1 Department of Pediatric Dentistry, Faculty of Dentistry, Bülent Ecevit University, 67600 Kozlu, Zonguldak, Turkey
2 Department of Endodontics, Faculty of Dentistry, Bülent Ecevit University, 67600 Kozlu, Zonguldak, Turkey
|Date of Web Publication||17-Jun-2016|
Department of Pediatric Dentistry, Faculty of Dentistry, Bülent Ecevit University, 67600 Kozlu, Zonguldak
Source of Support: None, Conflict of Interest: None
Background: Electronic apex locators (EALs) have become popular to measure the working length in permanent teeth in recent years, and they have helped for estimation of the working length more accurate. Objective: The purpose of this study is to evaluate the accuracy of ProPex II, Raypex 6 and iPex II EALs in primary molar teeth. Materials and Methods: Fifteen mandibular primary second molar teeth with 48 root canals were measured by all EALs. The direct length (DL) of the root canals was measured visually. The differences between DL and electronic working length (EWL) measurements of each device were calculated. Statistically analysis was performed using Student's t-test, and the significance level was at 5%. Results: For the measurements of ProPex II, the reliability of ±0.5 mm was determined in 77% of all root canals. For Raypex 6, the same result (77%) was observed when the accuracy was also accepted as ±0.5 mm. On the other hand, the result was found as 79% in the measurements of iPex II when the same accuracy limit (±0.5 mm) was considered. When the accuracy limit was ±1 mm, the determined values were 96% for ProPex II and Raypex 6 and 94% for iPex II. There was no significant difference between each EAL group (P > 0.05). Conclusion: The ProPex II, Raypex 6, and iPex II EALs showed similar results and all tested EALs were able to determine the working length in primary molar teeth accurately.
Keywords: Apex locator, primary teeth, root canal
|How to cite this article:|
Demiriz L, Kocak MM, Saglam BC, Kocak S. In vitro evaluation of the accuracy of ProPex II, Raypex 6 and iPex II electronic apex locators in primary molar teeth. J Health Res Rev 2016;3:37-40
|How to cite this URL:|
Demiriz L, Kocak MM, Saglam BC, Kocak S. In vitro evaluation of the accuracy of ProPex II, Raypex 6 and iPex II electronic apex locators in primary molar teeth. J Health Res Rev [serial online] 2016 [cited 2022 Jul 6];3:37-40. Available from: https://www.jhrr.org/text.asp?2016/3/2/37/184227
| Introduction|| |
Primary teeth undertake important objectives such as chewing, speaking, and maintaining spaces for permanent teeth.  Early loss of them can cause serious problems such as breaking down of these functions.  Therefore, preservation of a primary tooth whose pulp has been endangered is the first aim of the pediatric dentist in caring for the teeth of children. ,
Endodontic treatment is essential to prevent the loss of primary teeth until the physiologic exfoliation when the pulp tissue becomes infected. , Detecting the accurate working length is a crucial step for reducing periapical inflammation, preventing injury of the succedaneous tooth bud, and successful endodontic treatment in primary teeth. ,,,, Using a radiographic technique has been the method which was chosen to detect the working length. However, accurate location of root apices with radiography technique is difficult because of some factors such as distortion of the image, superposition of roots, adjacent anatomical structures, and poor cooperation with children. ,,,,,, All these considered disadvantages have directed the researchers to using electronic apex locators (EALs) in deciduous teeth root canal treatments in recent years. ,
EALs have gained more popularity to determine working length in permanent teeth in recent years, and they have helped for estimation of the working length and have increased precision rates. ,, However, the preference of EALs in primary teeth is not suggested universally since root resorption.  Despite this, the efficacy and safety of using EALs in detecting working length in primary teeth were shown by several researches. ,,, In addition, EALs cause no pain and prevent radiation, and since these advantages, they were recommended to be used among children during root canal treatment in clinical practice. ,,, However, the data about the accuracy of new developed EALs in the primary dentition are limited.
The aim of this study was to investigate the accuracy of three different new developed EALs; ProPex II, Raypex 6, and iPex II for root canal length detection in laboratory (in vitro) conditions, compare their efficacy with each other, and evaluate the use of these new EALs in primary teeth root canal treatment.
| Materials and methods|| |
Before this study, the ethical approval was given by the Ethics Committee of Bulent Ecevit University (Protocol Number: 33479383/14). In this study, 15 primary mandibular second molar teeth, which were stored in saline at 4°C after extraction, were selected. The teeth which were extracted because of severe caries that makes tooth crown restoration impossible were used. All teeth were kept in 5.25% sodium hypochlorite for 15 min to remove all organic remnants, and calculus or stains were cleared from tooth surface with scalers and curettes. All roots were examined with radiographs and magnifying glasses to identify any fracture or obliteration. Roots which had any of these conditions were excluded from the study. After the election, regardless of apical root resorption, 48 roots were included in this study and all teeth were coded. The acceptable limit of physiological root resorption was the half of the root length.
The preparations of all the access cavities were completed using tungsten carbide burs and the root canals were left unflared. The actual length of each root was determined using magnifying glasses (×2). #10 or #15 K-file (Dentsply-Maillefer Instruments SA, Ballaigues, Switzerland) instruments were inserted until they emerged at the resorption area or apical foramen. After that process, the rubber stopper was placed to a reference edge in occlusal surface for each tooth. Then, the file was removed, and the distance between rubber stop and the tip of the file was measured using a digital caliper which was in 0.01 mm resolution. The procedure was repeated for 3 times, and average values of these three measurements were recorded for each root canal.
In vivo conditions were simulated by embedding the specimens and a labial clip of apex locator in a freshly mixed alginate model. For irrigation, 2.5% sodium hypochlorite was used in all root canals. The EWL determination was performed with ProPex II (Dentsply-Maillefer, Tulsa, OK, USA), Raypex 6 (VDW GmbH, Munich, Germany), and iPex II (NSK, Tochigi, Japan) EALs according to the information which was given by the manufacturers. In EWL determination, the file was placed into the root canal, and the rubber stopper was placed to the reference point until the sound of beeping was heard, and the light-emitting diode signed the apex on the panel of each device. Then, the file was carefully withdrawn from the root canal, and the measurement was recorded using the same digital caliper. The procedure was repeated for 3 times, and average values of these three measurements were recorded for each root canal.
All data were saved as table in Excel (Microsoft, Redmond, WA, USA). For each root canal, the difference between direct length (DL) and electronic length (EWL) measurements of each device (coded for ProPex II: EWL1, Raypex 6: EWL2, and iPex II: EWL3, respectively) were calculated (DL-EWL1; DL-EWL2; DL-EWL3). Calculated values were grouped as stated at below: 
- <−1 mm
- Between −1 and −0.51 mm
- Between −0.5 mm and +0.50 mm
- Between +0.51 mm and +1 mm
- +1 mm.
For statistical analysis, the Student's t-test was performed using the version 17 SPSS (Chicago, IL, USA), and P < 0.05 was considered statistically significant.
| Results|| |
All reliability levels of EALs were shown in [Table 1]. For the measurements of ProPex II, the accuracy of ±0.5 mm was determined in 77% of all root canals. For Raypex 6, the same result (77% of the root canals) was observed when the accuracy was also accepted as ±0.5 mm. On the other hand, the result was found as 79% in the measurements of iPex II when the same accuracy limit (±0.5 mm) was considered. When the accuracy limit was ±1 mm, the determined values were 96% for ProPex II and Raypex 6 and 94% for iPex II. Mean differences between all groups (DL, ProPex II, Raypex 6, iPex II) were shown in [Table 2]. There was no significant difference between each EAL group (P > 0.05).
|Table 1: Frequency of the measurements of three different electronic apex locators at different distances from the apical foramen|
Click here to view
| Discussion|| |
The determination of the accurate working length is an important step in the endodontic treatment of deciduous teeth to provide effective preparation and cleaning of root canals. In addition, the detection of the accurate working length prevents the damage of permanent tooth germ and periapical tissues during the preparation of root canal with endodontic instruments. However, traditional radiographic methods have some limitations in detection of the accurate working length in deciduous teeth root canals because of superposition of images, root resorption and hard tissue deposition. ,
Regardless of the electrolyte, actual EALs have the properties of high reliability, accuracy and reproducibility in the location of the apical foramen.  Moreover, EALs are more practical, tolerable and safer than conventional radiographs,  and they potentially reduce the number of taken radiographs during the root canal treatment.  Since such advantages using EALs to determine working length has increased considerably for the primary dentition in recent years. ,,,,
Root canals have uncertainty about apical endpoint because of occurring physiological and pathological resorption, , and there are no rigid rules for the measurement of the root canal length in primary teeth.  In addition to these conditions, acceptable measurement with EALs in primary teeth topic is controversial.  Some authors consider the acceptable measurement to be ±0.5 mm between direct and EWL, , whereas some others consider the measurement to be ±1 mm. ,, In this study, the reliability of each EAL was determined by considering both differences (±0.5 and ±1 mm).
Regarding ±0.5 mm, ProPex II revealed an accuracy of 77%, Raypex 6 revealed an accuracy of 77%, and iPex II revealed an accuracy of 79%, respectively. When the difference was accepted as ±1 mm, these results changed as follows 94%, 94%, and 96%, respectively. All EALs showed similar results with each other in ±0.5 and ±1 mm difference. Beltrame et al.  reported that the EAL revealed an ex vivo accuracy of 69-77% in ±0.5 mm difference. In the same study, the results were 92-94% when the difference was considered as ±1 mm.  The accuracy of EAL was found 89% and 83% for roots with or without resorption, respectively in ±0.5 mm difference.  On the other hand, considering the difference of ±1 mm in the same study, the result was 99% for roots with resorption whereas it was 98% for roots without resorption. In an in vivo study, the accuracy of an EAL was 81% in ±0.5 mm and 96% in ±1 mm difference.  These findings support our results that root resorption does not negatively affect the reliability of the EALs, which is being tested. Thus, Bahrololoomi et al.  used an EAL to measure the root canal lengths in deciduous anterior teeth, and they reported that EALs can be used as a reliable tool to obtain the root canal length in primary anterior teeth with resorption. Similarly, Kielbassa et al.  used an EAL to measure the root canal length in in vivo conditions and they determined no differences between roots with or without resorption. In a recent study, Kumar et al.  showed that the evaluated EAL showed the most promising results, followed by radiovisiography and conventional radiography. In a meta-analysis study,  it was well reported that EALs provide an acceptable level of accuracy in determining the root canal length in primary teeth.
| Conclusion|| |
In this study, the tested EALs (ProPex II, Raypex 6, and iPex II) proved accuracy in detection of root canal length in primary dentition and supported the findings of previous studies. ,,,, The ProPex II, Raypex 6, and iPex II EALs showed similar results and all tested EALs were able to determine the working length in deciduous molar teeth accurately, regardless of the root resorption.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]