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Year : 2020  |  Volume : 32  |  Issue : 4  |  Page : 231-233

Effect of diode laser irradiation and 10% citric acid conditioning on the sealing ability of mineral trioxide aggregate as a retrograde filling material

Department of Conservative Dentistry and Endodontics, Al Badar Dental College and Hospital, Kalaburgi, Karnataka, India

Date of Submission26-Apr-2020
Date of Decision28-Oct-2020
Date of Acceptance09-Dec-2020
Date of Web Publication18-Jan-2021

Correspondence Address:
Dr. Shailendra Mashalkar
Department of Conservative Dentistry and Endodontics, Al Badar Dental College and Hospital, Kalaburgi, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/endo.endo_58_20

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Aim: The aim was to evaluate the effect of diode laser irradiation and 5% citric acid conditioning on microleakage of mineral trioxide aggregate (MTA) when used as root-end filling material.
Materials and Methods: Forty-five human anterior teeth were decoronated and subjected to root canal instrumentation. Three millimeters of apical root portion was resected, and root-end cavities were prepared using ultrasonic tips. The teeth were then randomly divided into three groups (n = 15), In Group 1 – root-end cavity was prepared and treated with citric acid followed by MTA application; in Group 2 – root-end cavity was prepared and treated with diode laser followed by MTA application; and in Group 3 – root-end cavity was prepared and treated with citric acid and laser application followed by MTA application. The specimens were then subjected to glucose leakage analysis at 48 h, 7 days, and 14 days. One-way ANOVA test was used for raw data and Chi-square test for consolidated data to test the significance of difference between the variables. SPSS software version 20 was used for analyzing the data.
Results: Group 1 showed significantly more leakage than Group 2 and Group 3 at all time intervals, whereas Group 3 showed the least microleakage at 48 h, 7 days, and 14 days.
Conclusion: MTA had a better sealing ability when root-end cavities were conditioned with 5% citric acid followed by diode laser irradiation.

Keywords: Citric acid, lasers, mineral trioxide aggregate cement

How to cite this article:
Mashalkar S, Mohiuddin Hussaini SM, Diwanji P, Indi S, Hambire A. Effect of diode laser irradiation and 10% citric acid conditioning on the sealing ability of mineral trioxide aggregate as a retrograde filling material. Endodontology 2020;32:231-3

How to cite this URL:
Mashalkar S, Mohiuddin Hussaini SM, Diwanji P, Indi S, Hambire A. Effect of diode laser irradiation and 10% citric acid conditioning on the sealing ability of mineral trioxide aggregate as a retrograde filling material. Endodontology [serial online] 2020 [cited 2022 Aug 8];32:231-3. Available from: https://www.endodontologyonweb.org/text.asp?2020/32/4/231/307315

  Introduction Top

Successful elimination of pathogens, sealing all avenues to prevent re-infection and allowing healing to take place, determines the success of endodontic therapy.[1] Inadequate cleaning, shaping, and obturation and loss of coronal seal due to operator errors may lead to failure of root canal treatment.[2],[3],[4],[5] Surgical endodontic therapy becomes the last choice in saving the tooth from being extracted when nonsurgical retreatment fails to give the desired results.[6]

During periradicular surgery, instrumentation of root dentin surface results in the production of smear layer.[7] The prepared dentin surface should be very clean to increase sealing ability, and it has been stated that application of acids or chelating agents helps in the elimination of smear layer and improves the adhesion and penetration of root-end filling materials.[8] Irradiation with diode laser has performed significantly better in modifying the smear layer along with bacteriocidal effect and occluding dentinal tubules.[9]

Numerous studies have suggested that on one hand chelating agents such as citric acid remove smear layer[8] and on the other hand laser irradiations occlude or narrow dentinal tubules,[9] therefore in this study, it was decided to observe the effects of both on sealing ability of MTA when used as retrograde filling material.

  Materials and Methods Top

Forty-five human maxillary central incisors with relative similar dimensions as examined by intraoral periapical radiographs (buccolingual and mesiodistal directions) extracted for periodontal reasons were selected based on the inclusion (caries free, single root canal, and completely formed apex) and exclusion criteria (open apex or incompletely formed apex, root resorptions, cracks, and endodontic restorations). The teeth were thoroughly cleaned using ultrasonics and stored in 0.2% of sodium azide (EMPARTA, Mumbai, Maharashtra, India) at 4°C. The teeth were decoronated and the root length was adjusted to 15 mm. Straight-line access was established, and the working length was determined manually by inserting no. 10 K-file (Kiyoharakogyodanchi, Utsunomiya, Tochigi 321-3231, Japan) into the root canal until it was visible from the apex and 1 mm was subtracted from that point. The canals were enlarged to size F3 using rotary protaper files (Dentsply, Bangalore, Karnataka, India) with intermittent irrigation by 3% sodium hypochlorite (Prime Dental, Mumbai, Maharashtra, India) and finally with 5 mL of distilled water. The canals were then dried using paper points (Dentsply, India). Apicoectomy was performed using diamond burs and coolants while maintaining near parallelism. Three millimeters of deep root-end cavities was prepared using an ultrasonic tip (AS3D, 15-21 Rue Thalès, 33700 Mérignac, France) and a water coolant. The 45 samples were divided into three groups (n = 15), as follows:

  • Group 1 – Root-end cavity conditioned with 10% citric acid followed by root-end filling with mineral trioxide aggregate (MTA)
  • Group 2 – Root-end cavity irradiated with diode laser (4 Cromwell, Irvine, CA 92618, USA.) at 2 W/cW for 20 s followed by root-end filling with MTA
  • Group 3 – Root-end cavity conditioned with 10% citric acid followed by diode laser irradiation for 20 s and filled with MTA as root-end filling.

All the roots were kept in 100% humidity at 37°C for 48 h.

Evaluation of microleakage

Microleakage was evaluated using glucose penetration model. The coronal part of each root was glued to one end of a modified plastic dropper (in which both ends were cut to accommodate the specimen and the glass tube) using cyanoacrylate. Care was taken so that the glue does not cover the coronal orifice of the root. Through the other end, a glass tube of 15 cm in length was connected and sealed. The assembly was then placed in a sterile 5-mL glass bottle covered with a paraffin sheet and sealed with sticky wax. 1 mol/L glucose solution (pH = 7.0), with a density of 1.09 × 103 g/L at 37°C, was used, which created a hydrostatic pressure of 1.5 kPa (15 cmH2O) at 14 cm.

Measurement of microleakage

One hundred-microliter aliquot of the solution was drawn from the glass beaker using a micropipette after 48 h, 7 days, and 14 days. After drawing the sample, 100 μL of fresh 0.2% sodium azide was added to the glass bottle reservoir to maintain a constant volume of 1 mL. The sample was analyzed with a glucose kit in a colorimeter at 500-nm wavelength. The results of leakage in all groups were calculated as mmol/L from the respective optical density observed in a colorimeter.

Statistical analysis

One-way ANOVA test was used for raw data and Chi-square test for consolidated data to test the significance of difference between variables.

SPSS software version 20 (IBM, Bangalore, India) was used for analyzing the data.

P” < 0.05 was considered statistically significant.

  Results Top

Group 1 (10% citric acid) showed maximum leakage at 48-h interval as compared to Group 2 (laser irradiation) and Group 3 (laser irradiation + 10% citric acid).

The histogram of the mean leakage of the three groups at 48 h, 7 days, and 14 days is shown in [Figure 1].
Figure 1: Average leakage observed among the groups at 48 h, 7 days, and 14 days

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There was a significant difference between Group 2 (laser irradiation) and Group 3 (laser irradiation + 10% citric acid group) at 7 days and 14 days when compared with that of Group 3 (laser irradiation + 10% citric acid) which demonstrated the least leakage.

  Discussion Top

The success of periradicular surgery depends on the tight seal that is obtained mainly due to the root-end filling material and the conditions of its placement.[10]

MTA is considered the most successful retrograde filling material till date.[11] Exclusive research has shown its superiority when used as a restorative material with excellent sealing and marginal adaptability.[12],[13],[14] When applied on external root surfaces with 2 W/cW of power in vitro without previous scaling or root planing procedures, the diode laser caused dentinal permeability to decrease in the cases of dentinal hypersensitivity. No melting, fusion, or carbonizations were found in this power setting. In the present study, the diode laser was applied with 2 W/cW on the root-end cavity surfaces before retrofilling with MTA to avoid interaction between the diode laser and MTA. Using the diode laser after retrofilling with MTA would increase the temperature, which might crack the retrofilling.[15] Citric acid is a chelator which has the right power to remove the smear layer and at the same time not weaken the root surface.

Glucose filtration technique was introduced by Xu et al. for quantitative testing of endodontic leakage.[16] This quantitative technique is sensitive, nondestructive, and clinically relevant. The rationale for using glucose as a tracer in this study was due to its small molecular size and it is a known nutrient for the bacteria.[17]

In the present study, the root-end cavity when treated with 10% citric acid and irradiation with laser and filled with MTA showed the least microleakage, which may be attributed to the fact that citric acid removed the smear layer and the laser might have modified the diameter of the dentinal tubules, aiding in the sealing ability of MTA, hence satisfying the research hypothesis.

  Conclusion Top

Within the limitations of this study, it can be concluded that 10% citric acid application to the prepared root-end surface and subsequent laser irradiation can be an effective adjunct with MTA as a root-end filling material.


I affirm that I/We have no financial affiliation (e.g., employment, direct payment, stock holdings, retainers, consultantships, patent licensing arrangements, or honoraria), or involvement with any commercial organization with direct financial interest in the subject or materials discussed in this manuscript, nor have any such arrangements existed in the past 3 years. Any other potential conflict of interest is disclosed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Torabinejad M, Watson TF, Pitt Ford TR. Sealing ability of a mineral trioxide aggregate when used as a root end filling material. J Endod 1993;19:591-5.  Back to cited text no. 1
West JD. The Relation between the Three-Dimensional Endodontic Seal and Endodontic Failure, Master Thesis, Boston University; 1975.  Back to cited text no. 2
Torabinejad M, Ung B, Kettering JD. In vitro bacterial penetration of coronally unsealed endodontically treated teeth. J Endod 1990;16:566-9.  Back to cited text no. 3
Alves J, Walton R, Drake D. Coronal leakage: Endotoxin penetration from mixed bacterial communities through obturated, post-prepared root canals. J Endod 1998;24:587-91.  Back to cited text no. 4
Southard DW. Immediate core buildup of endodontically treated teeth: The rest of the seal. Pract Periodont Aesthet Dent 1999;11:519-26.  Back to cited text no. 5
Bergenholtz G, Lekholm U, Milthon R, Heden G, Odesjö B, Engström B. Retreatment of endodontic fillings. Scand J Dent Res 1979;87:217-24.  Back to cited text no. 6
Peters LB, Harrison JW. A comparison of leakage of filling materials in conditions. Int Endod J 1992;25:273-8.  Back to cited text no. 7
Sen BH, Wesselink PR, Türkün M. The smear layer: A phenomenon in root canal therapy. Int Endod J 1995;28:141-8.  Back to cited text no. 8
Amin K, Masoodi A, Nabi S, Ahmad P, Farooq R, Purra AR, et al. Effect of diode laser and ultrasonics with and without EDTA on smear layer removal from the root canals: A scanning electron microscope study. J Conserv Dent 2016;19:424-7.  Back to cited text no. 9
[PUBMED]  [Full text]  
Kim S, Kratchman S. Modern endodontic surgery concepts and practice: A review. J Endod 2006;32:601-23.  Back to cited text no. 10
Macwan C, Deshpande A. Mineral trioxide aggregate (MTA) in dentistry: A review of literature. J Oral Res Rev 2014;6:71-4.  Back to cited text no. 11
  [Full text]  
Torabinejad M, Hong CU, McDonald F, Pitt Ford TR. Physical and chemical properties of a new root-end filling material. J Endod 1995;21:349-53.  Back to cited text no. 12
Xavier CB, Weismann R, de Oliveira MG, Demarco FF, Pozza DH. Root-end filling materials: Apical microleakage and marginal adaptation. J Endod 31;7:539-42.  Back to cited text no. 13
Chhaparwal S, Ballal NV, Menezes ND, Kamath SU. Effect of chelating agents on sealing ability of Biodentine and mineral trioxide aggregate. Saudi Endod J 2017;7:16-22.  Back to cited text no. 14
  [Full text]  
Liu Y, Gao J, Gao Y, Xu S, Zhan X, Wu B. In vitro study of dentin hypersensitivity treated by 980-nm diode laser. J Lasers Med Sci 2013;4:111-9.  Back to cited text no. 15
Xu Q, Fan MW, Fan B, Cheung GS, Hu HL. A new quantitative method using glucose for analysis of endodontic leakage. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005;99:107-111.  Back to cited text no. 16
Hegde V, Arora S. Sealing ability of three hydrophilic single-cone obturation systems: An in vitro glucose leakage study. Contemp Clin Dent 2015;6:S86-9.  Back to cited text no. 17


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