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Year : 2022  |  Volume : 13  |  Issue : 1  |  Page : 20-23

Efficacy of XP-endo Finisher File on the Removal of Calcium Hydroxide from the Root Canals: An In Vitro Study

1 Department of Endodontics, Dental Caries Prevention Research Center, Qazvin University of Medical Sciences, Qazvin, Iran
2 Student Research Committee, Qazvin University of Medical Sciences, Qazvin, Iran
3 Department of Periodontics, Dental Caries Prevention Research Center, Qazvin University of Medical Sciences, Qazvin, Iran

Date of Submission06-Jul-2021
Date of Decision23-Dec-2021
Date of Acceptance23-Jan-2022
Date of Web Publication29-Apr-2022

Correspondence Address:
Orkideh Alavi
Qazvin University of Medical Sciences, Shahid Bahonar Blvd, Qazvin, Postal Code 3415851856
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/denthyp.denthyp_53_21

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Introduction: Calcium hydroxide must be completely removed from the root canal before the endodontic therapy. One of the methods to remove calcium hydroxide is XP-endo finisher file which has conflicting results. This study aimed to compare the efficacy of XP-endo finisher in removing calcium hydroxide with other irrigation methods. Materials and methods: In this experimental in vitro study, 48 teeth were selected. Each tooth was split longitudinally. Standardized grooves were prepared in the middle and apical third of the canals and then were filled with calcium hydroxide. The roots were randomly divided into three groups according to calcium hydroxide removal methods: XP-endo finisher, passive ultrasonic irrigation, and syringe needle irrigation. The amount of remaining medicament was evaluated using a scoring system. Chi-square was used to study the difference between the qualitative variables. The significant level was P < 0.05. Results: In the middle part, XP-endo finisher removed calcium hydroxide significantly higher than other methods (P = 0.005). In the apical part, no significant difference was observed among the groups (P = 0.47). Conclusion: All methods removed more calcium hydroxide in the middle than the apical part. In the middle part, XP-endo finisher removed calcium hydroxide more than the other methods from the root canals.

Keywords: Calcium hydroxide, root canal irrigants, root canal therapy, XP-endo finisher

How to cite this article:
Aflaki S, Alavi O, Zeynal-Kelishomi H, Darvish A, Karamshahi M. Efficacy of XP-endo Finisher File on the Removal of Calcium Hydroxide from the Root Canals: An In Vitro Study. Dent Hypotheses 2022;13:20-3

How to cite this URL:
Aflaki S, Alavi O, Zeynal-Kelishomi H, Darvish A, Karamshahi M. Efficacy of XP-endo Finisher File on the Removal of Calcium Hydroxide from the Root Canals: An In Vitro Study. Dent Hypotheses [serial online] 2022 [cited 2022 Dec 1];13:20-3. Available from:

  Introduction Top

Removal of the bacteria and their products from the root canal is the ultimate goal of endodontic therapy.[1] The most popular material used as an interappointment medicament is calcium hydroxide [Ca(OH)2].[2] Physical properties and penetration abilities of the sealer could be altered at the presence of Ca(OH)2 remnants; therefore, Ca(OH)2 must be completely removed before root canal filling.[3] There are numerous instruments and techniques to remove Ca(OH)2 including NiTi and stainless steel instruments, rotary systems, and conventional syringe and needle irrigations (SNIs); but none of these methods can completely remove calcium residues.[4]

XP-endo finisher (XPF; FKG, La Chaux-de-Fonds, Switzerland) is one of the new files of the NiTi system that has been introduced to disinfecting the canal. The manufacturer claims that this file can efficiently remove smear layer and clean irregular areas when maintaining the original anatomy. This can be due to the remarkable flexibility of the file to match the root canal system three-dimensionally.[1],[3]

Several studies have evaluated the efficiency of XPF.[5],[6] Regarding the controversies and given that few studies have been conducted on Ca(OH)2 removal using XPF,[6],[7],[8] we compared the efficacy of this file on removing Ca(OH)2 with SNI and passive ultrasonic irrigation (PUI) methods in the extracted mandibular premolars. Null hypothesis is that there is no difference between different methods in terms of calcium removal.

  Materials and Methods Top

This study has been approved by the ethics committee (IR.QUMS.REC.1396.313). In this in vitro study, human single root premolars extracted for orthodontic or periodontal reasons were selected. Considering proportions reported by Elnaghy et al.’s study,[9] type I error of 0.05 and type II error of 0.02, the total number of samples was calculated to be 48 [Supplementary Figure 1].[10] Teeth with resorption, curvature, calcification, pulp stone, root caries, immature apex, previous restoration, fracture, and previous root canal treatment were excluded from the study.

Sample preparation

The teeth were immersed in chloramine-T 0.5% solution for 48 hours and then kept in distilled water at 4°C for up to 1 month. Before the experiment, debris were removed on the surface of the tooth. The crowns were cut by carbide fissure bur no. 0010 (Teeskavan, Tehran, Iran) to produce a standard length of 15 mm as the reference point. After the access to the canal, K file no. 10 (Dentsply Maillefer, Balaigues, Switzerland) was entered until the file tip reached the apical foramen. One millimeter was reduced in length, and 14 mm was considered as the working length. Glide path preparation of the canals was performed with size 20 RaCe instrument (FKG) up to file 40 (0.06). The canals were irrigated with 2 mL of 5.25% sodium hypochlorite (Cerkamed Medical Company, Stalowa, Poland) between each file. Each sample was flushed again with 2 mL of normal saline (SAMEN Co., Mashhad, Iran) and smear layer was removed with 1 mL 17% ethylenediaminetetraacetic acid (EDTA) solution (Morvabon, Tehran, Iran) for 1 minute followed by 5 mL 5.25% sodium hypochlorite irrigation with a 25-gauge syringe (SUPA medical devices, Tehran, Iran), 1 mm shorter than the working length.

Ca(OH)2 placement

The samples were mounted on a silicone material (Coltene, Langenau, Germany). Then two fissures were made by diamond disk (Teeskavan) under water-spray on the mesial and distal surfaces. The root was divided into two parts by a chisel and two grooves (length = 3 mm, width = 0.5 mm, depth = 0.5 mm) were made using a diamond bur (Teeskavan) No. 006 on each half of the tooth in the middle and apical part. Five milliliter 17% EDTA solution followed by 5 mL sodium hypochlorite were used for 60 seconds for the final flush, and the canals were dried with paper points (Diadent, Cheongju, Korea). The grooves were examined by a stereomicroscope under ×25 magnification; two images of each half were taken, one from the middle groove and the other from apical third. Ca(OH)2 paste (Golchai Co, Tehran, Iran) was used to fill the canals. Then, the root parts were bonded by cyanoacrylate adhesive (Razi Chemical Co, Tehran, Iran) and the canal orifices were filled with a cotton pellet and cavit (3M ESPE, Seefeld, Germany). The samples were incubated for 7 days in 100% moisture at 37°C. Finally, three irrigation methods (n = 16 for each group) including SNI, XPF, and PUI were exerted on the samples. Samples were randomly assigned following simple randomization procedure (by coin toss) to each treatment groups by an independent researcher (MK). The allocation sequence was concealed in sequentially numbered, opaque, sealed envelopes. All procedures were carried out by an endodontist expert (OA). Outcome assessors (analysis of residual Ca(OH)2) and data analyst were kept blind.

Ca(OH)2 removal methods

Conventional syringe and needle irrigation group

The canals were irrigated with 5 mL 5.25% sodium hypochlorite and 5 mL 17% EDTA solution using a 30-gauge syringe, 1 mm shorter than working length.

Passive ultrasonic irrigation group

The canals were flushed as described in the SNI protocol with activation by ultrasonic tip (No. 25; Woodpecker®, Guilin Medical Instrument Co., Guangxi, China) for 60 seconds.

XP-endo finisher group

The canals were flushed with 5 ml 5.25% sodium hypochlorite. Then, XPF was inserted into the canal (800 RPM and 1 Ncm torque) in a vertical motion with a range of 7 to 8 mm in length for 1 minute. Afterward, the samples were flushed with 5 mL of 17% EDTA solution. XPF was used again for 1 minute.

Analysis of residual Ca(OH)2

The samples were imaged at ×25 magnification. Two independent endodontists who were blind to the groups rated the images separately according to Van der Sluis scoring system[11]:
  • Score 3: Ca(OH)2 filled the grooves completely [Figure 1]a
  • Score 2: Ca(OH)2 covered more than half of groove [Figure 1]b
  • Score 1: Ca(OH)2 covered less than half of groove [Figure 1]c
  • Score 0: No Ca(OH)2 residue covers the groove [Figure 1]d
Figure 1 Assessment of calcium hydroxide [Ca(OH)2] removal from the artificial groove using score system. (a) Score 3: the groove is completely filled/covered with Ca(OH)2. (b) Score 2: more than half of the groove surface is covered with Ca(OH)2. (c) Score 1: less than half the groove surface is covered with Ca(OH)2. (d) Score 0: the groove is clean of any Ca(OH)2 residue.

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Statistical analysis

Kappa values were calculated for interobserver agreement evaluation. The difference of Ca(OH)2 remnants between the experimental groups and between middle and apical parts in each group was analyzed by Chi-square test. Data analysis was then carried out using SPSS ver. 24 (SPSS, Chicago, IL, USA).The significance level was <0.05.

  Results Top

The kappa values for interobserver reproducibility were 0.90. The Ca(OH)2 removal rate using XPF was significantly higher than the two other methods in the middle part of the canals (P = 0.005). In apical third, XPF and PUI were able to remove Ca(OH)2 more than SNI, although no significant difference was found among three methods (P = 0.47) [Supplementary Figure 2].[12]

Ca(OH)2 removal in the middle part was significantly more than the apical part in XPF (P = 0.00) and PUI (P = 0.019) groups. In SNI method, the difference of Ca(OH)2 removal between the middle and the apical part was not significant (P = 0.34) [Supplementary figure 3[13]; [Table 1]].
Table 1 Frequency of scores in the three experimental groups in the middle and apical third of canals

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  Discussion Top

Several studies have been investigated the removal of Ca(OH)2 from the root canal in which different irrigation techniques and instruments have been evaluated.[14],[15] In some studies, the Ca(OH)2 removal has been assessed with standard artificial groove model.[2],[11],[16] This model can simulate irregularities of the canals in the straight roots and standardize the location and size of the grooves, and the medicament volume used. In our study, the teeth were decoronated to obtain the same length of the canals, although the clinical condition is not completely simulated.

Various methods such as scoring, standard error mean, and micro-computed tomography (CT) has been utilized to evaluate the volume of Ca(OH)2 residues on the dentinal walls.[16],[17] In this study, the scoring method detailed by Van der Sluis et al.[11] was used.

The amount of Ca(OH)2 removal varies between different parts of root canal.[15] Although complete removal was not occurred by any of the methods in the present study, PUI and XPF removed Ca(OH)2 significantly higher in the middle part. Ca(OH)2 removal is more difficult in the apical third.[18],[19] This could be due to the lower velocity and smaller volume of the irrigating solution flow in the apical third. More irregularities and less in number of the dentinal tubules in the apical region may be another possible reason for this difference.[19]

In the present study, XPF removed Ca(OH)2 significantly more than the other groups in the middle part, which is in agreement with previous studies.[7] One of the reasons for this can be due to the XPF properties. Unlike the conventional NiTi instruments, shape of XPF will change with alterations in temperature enabling it to expand to adapt to the root canal system and clean the inaccessible regions.[1] Keskin et al.[3] reported that XPF and PUI removed Ca(OH)2 higher than the other methods with no significant difference. They compared the techniques in simulated resorption cavities instead of artificial grooves. Another study evaluated the efficiency of four techniques to remove hard tissue debris and found significant superiority of XPF and PUI.[4] They measured accumulated hard-tissue debris in the root canal without artificial grooves. Additionally, the type of teeth examined in that study were mesial roots of the first molars.

The present study showed that in the apical third, XPF and PUI removed Ca(OH)2 more than SNI, but no significant difference was found between them. In the apical areas, due to the small diameter of the canal, it was not possible for irrigating methods to access the Ca(OH)2 residues, and this caused the differences to be insignificant. Two studies reported that XPF significantly removed more Ca(OH)2 than PUI in the apical third.[2],[8] In Hamdan et al. study,[8] artificial groove model was not used for standardization of Ca(OH)2 quantity. Moreover, different type of the teeth and working lengths could be justified these differences.[2]


Due to the in vitro design of the study, the results cannot be generalized to clinical conditions. The use of micro-CT is also suggested for accurate evaluation of Ca(OH)2 residues in the future studies.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Uygun AD, Gündoğdu EC, Arslan H, Ersoy İ. Efficacy of XP-endo finisher and TRUS hape 3D conforming file compared to conventional and ultrasonic irrigation in removing calcium hydroxide. Aust Endod J 2017;43:89-93.  Back to cited text no. 1
Wigler R, Dvir R, Weisman A, Matalon S, Kfir A. Efficacy of XP-endo finisher files in the removal of calcium hydroxide paste from artificial standardized grooves in the apical third of oval root canals. Int Endod J 2017;50:700-5.  Back to cited text no. 2
Keskin C, Sariyilmaz E, Sariyilmaz Ö. Efficacy of XP-endo Finisher file in removing calcium hydroxide from simulated internal resorption cavity. J Endod 2017;43:126-30.  Back to cited text no. 3
Leoni GB, Versiani MA, Silva-Sousa YT, Bruniera JF, Pécora JD, Sousa-Neto MD. Ex vivo evaluation of four final irrigation protocols on the removal of hard-tissue debris from the mesial root canal system of mandibular first molars. Int Endod J 2017;50:398-406.  Back to cited text no. 4
Velozo C, Albuquerque D. Microcomputed tomography studies of the effectiveness of XP-endo shaper in root canal preparation: a review of the literature. Sci World J 2019;2019:3570870.  Back to cited text no. 5
Kolli S, Balasubramanian SK, Kittappa K, Mahalaxmi S. Efficacy of XP-endo Finisher files in endodontics. Aust Endod J 2018;44:71-2.  Back to cited text no. 6
Marques-da-Silva B, Alberton CS, Tomazinho FSF, Gabardo MCL, Duarte MAH, Vivan RR, Baratto-Filho F. Effectiveness of five instruments when removing calcium hydroxide paste from simulated internal root resorption cavities in extracted maxillary central incisors. Int Endod J 2020;53:366-75.  Back to cited text no. 7
Hamdan R, Michetti J, Pinchon D, Diemer F, Georgelin-Gurgel M. The XP-endo Finisher for the removal of calcium hydroxide paste from root canals and from the apical third. J Clin Exp Dent 2017;9:e855-60.  Back to cited text no. 8
Elnaghy AM, Mandorah A, Elsaka SE. Effectiveness of XP-endo Finisher, EndoActivator, and file agitation on debris and smear layer removal in curved root canals: a comparative study. Odontology 2017;105:178-83.  Back to cited text no. 9
Karamshahi M. Supplementary figure 1. figshare. Figure. 2022.  Back to cited text no. 10
Van der Sluis LW, Wu MK, Wesselink PR. The evaluation of removal of calcium hydroxide paste from an artificial standardized groove in the apical root canal using different irrigation methodologies. Int Endod J 2007;40:52-7.  Back to cited text no. 11
Karamshahi M. Supplementary figure 2. figshare. Figure. 2022.  Back to cited text no. 12
Karamshahi M. Supplementary figure 3. figshare. Figure. 2022.  Back to cited text no. 13
Kenee D, Allemang J, Johnson J, Hellstein J, Nichol B. A quantitative assessment of efficacy of various calcium hydroxide removal techniques. J Endod 2006;32:563-5.  Back to cited text no. 14
Capar I, Ozcan E, Arslan H, Ertas H, Aydinbelge H. Effect of different final irrigation methods on the removal of calcium hydroxide from an artificial standardized groove in the apical third of root canals. J Endod 2014;40:451-4.  Back to cited text no. 15
Arslan H, Akcay M, Capar ID, et al. An in vitro comparison of irrigation using photon-initiated photoacoustic streaming, ultrasonic, sonic and needle techniques in removing calcium hydroxide. Int Endod J 2015;48:246-51.  Back to cited text no. 16
Vineeta N, Gupta S, Chandra A. Retrievabilty of calcium hydroxide intracanal medicament with Chitosan from root canals: an in vitro CBCT volumetric analysis. J Conserv Dent 2014;17:454-7.  Back to cited text no. 17
[PUBMED]  [Full text]  
Ethem Yaylali I, Kececi A, Ureyen Kaya B. Ultrasonically activated irrigation to remove calcium hydroxide from apical third of human root canal system: a systematic review of in vitro studies. J Endod 2015;41:1589-99.  Back to cited text no. 18
Gokturk H, Ozkocak I, Buyukgebiz F, Demir O. Effectiveness of various irrigation protocols for the removal of calcium hydroxide from artificial standardized grooves. J Appl Oral Sci 2017;25:290-8.  Back to cited text no. 19


  [Figure 1]

  [Table 1]


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