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Year : 2022  |  Volume : 33  |  Issue : 3  |  Page : 318-322
Comparison of sealing ability of MTA and retroplast as root end filling materials evaluated under a stereomicroscope using rhodamine B dye: An In vitro study

1 Department of Conservative Dentistry and Endodontics, NIMS Dental College and Hospital, Jaipur, Rajasthan, India
2 Department of Conservative Dentistry and Endodontics, Rajasthan Dental College and Hospital, Jaipur, Rajasthan, India
3 Department of Orthodontics, RUHS College of Dental Sciences, Jaipur, Rajasthan, India
4 Conservative Dentistry and Endodontics, Vardhman Multispecialty Dental Clinic, Meerut, Uttar Pradesh, India

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Date of Submission19-Apr-2022
Date of Decision29-Aug-2022
Date of Acceptance02-Sep-2022
Date of Web Publication17-Jan-2023


Aim: The aim of the study was to compare the sealing ability of Mineral Trioxide Aggregate (MTA) and Retroplast as root end filling materials using the Rhodamine B dye penetration method in vitro. Methodology: Forty freshly extracted human single-rooted teeth were randomly divided into two groups of 20 teeth each, and standard root-end cavities were prepared in all teeth. The cavities were filled with MTA and Retroplast in groups 1 and 2, respectively. The specimens were then stored in 1% Rhodamine B dye for a week, following which the dye penetration with all samples was analysed under a stereomicroscope and scored according to Tronstad's criteria. The observations were compared with Chi square test at a 0.220 level of significance. Results: 5% of the samples in both the groups showed no significant leakage. The leakage was deeper with the Retroplast group than with the MTA group; however, there was no statistically significant difference between the two groups. Conclusion: Both MTA and Retroplast are similar in their sealing potential as root-end cavity fillings with Retroplast reporting slightly deeper microleakage than MTA within the limits of the present study.

Keywords: Mineral Trioxide Aggregate, Retroplast, Rhodamine B

How to cite this article:
Kararia N, Yadav A, Adyanthaya B R, Kararia V, Poonia S, Jain S. Comparison of sealing ability of MTA and retroplast as root end filling materials evaluated under a stereomicroscope using rhodamine B dye: An In vitro study. Indian J Dent Res 2022;33:318-22

How to cite this URL:
Kararia N, Yadav A, Adyanthaya B R, Kararia V, Poonia S, Jain S. Comparison of sealing ability of MTA and retroplast as root end filling materials evaluated under a stereomicroscope using rhodamine B dye: An In vitro study. Indian J Dent Res [serial online] 2022 [cited 2023 Feb 5];33:318-22. Available from:

   Introduction Top

The goal of endodontic therapy is to treat pulpal and peri-radicular inflammation or pathosis by the elimination of microorganisms from the root canal system. The most commonly used methods for microbial control include instrumentation, anti-microbial irrigation, intra-canal dressing, adequate obturation, and coronal restoration.[1] The most important factors for a successful endodontic treatment are the thorough cleaning and shaping of the root canal system, removal of infected dentin, and the complete obliteration of the root canal system and development of a fluid tight seal.[2] The recent studies have shown that modern rotary instruments are capable of achieving exceptionally clean root canals and they simultaneously preserve the original canal anatomy.[3],[4] Despite the constant evolution of concepts, new endodontic techniques, and the development of more effective materials and instruments, the resolution of periapical pathosis is not achieved in certain cases.[5] In such cases, where conventional endodontic treatment is unsuccessful, surgical endodontic therapy is needed to save the tooth.[6] This procedure includes exposure of the involved root apex, resection of the apical end of the root, preparation of class I cavity, and insertion of a root-end filling material.[7] The main objective of a root-end filling material is to provide a fluid tight seal both apically and coronally, thus preventing leakage and percolation of oral fluids and to prevent recontamination of disinfected canals by the movement of bacteria and the diffusion of bacterial products from the root canal system into the periapical tissues.[8] It has been proposed that an ideal root-end filling material should adhere to the preparation walls forming a tight seal in the root canal system.[9] Its anti-bacterial effects and ability to stimulate regeneration of the periodontium will accelerate the healing process and reduce the incidence of failures. Also, root-end materials must be non-toxic, non-irritant, radio-opaque, and non-corrosive. In addition to this, they should also be dimensionally stable and easy to manipulate. Over the years, several materials with a wide range in composition have been developed and tested for use as root-end filling materials. Of these, several materials such as Mineral Trioxide Aggregate (MTA) have shown promise and have been successfully used because of the desirable properties such as excellent seal and hard tissue repair compared with other root-end filling materials. The main advantages of MTA are its biocompatibility and its osteogenic and regenerative potential.[10] MTA has been demonstrated to have anti-bacterial properties against E. faecalis, S. aureus, and P. aeruginosa. Another composite resin-based material developed specifically for use as a root-end filling material is Retroplast. It is a dual-cure composite resin that uses a Gluma-based dentin bonding resin to adhere to the root-end surface preceded by etching with ethylenediaminetetraacetic acid gel. The present study attempts to compare the sealing ability of MTA and Retroplast as root-end filling materials using Rhodamine B dye penetration test.

   Materials and Methods Top

The study was approved by the Institutional Ethics Committee (NIMSUR/IEC/2021/0110). Forty freshly extracted human single-rooted teeth with completely formed apices and straight canals with no visible root caries, fracture, or cracks on examination and no signs of internal or external resorption or calcification were selected for the study and stored in normal saline. Radiographs were taken to confirm the above-mentioned criteria in bucco-lingual and mesio-distal views. The teeth were randomly divided into two groups of 20 specimens each: Group 1: Mineral Trioxide Aggregate (ProRoot MTA, Dentsply, Tulsa Dental Specialities, Tulsa); Group 2: Retroplast (Rorvig, Denmark).

The crowns of all teeth were removed at the cementoenamel junction with a diamond cutting disc (Shofu, India) mounted on a micromotor. Canal orifices were located, and after pulp extirpation, canal patency was confirmed with a #10 K file (Mani, Tochigi, Japan). Then #15 K file (Mani, Tochigi, Japan) was used to determine the working length with each root specimen. Root canals were prepared using a standardised technique until reaching a master apical file size #45 K file. The canals were irrigated between instruments with 3% sodium hypochlorite (Canal Pro, Coltene). The cleaned and shaped canals were then obturated with cold lateral compaction of gutta percha with the use of AH plus (Dentsply) as a sealer. Radiographs were taken to confirm the quality of obturation [Figure 1]a. The access cavity of each tooth was sealed with light cured composite resin (Filtek Z250, 3M). Apical root resections were performed by removing 3 mm of the root apex at 90° to the long axis of teeth with a straight fissure bur (SF 41, Mani, Tochigi, Japan) in a high-speed handpiece with a water coolant. A 3 mm deep root-end cavity was prepared with a straight fissure bur (SF 41, Mani, Tochigi, Japan) in a high-speed handpiece with a water coolant [Figure 1]b. The cavity floors were burnished with a heated plugger to smear the Gutta percha. The materials were manipulated according to the manufacturer's instructions, and root-end cavities were filled using ProRoot MTA and Retroplast in the respective groups and radiographs were taken [Figure 1]c and [Figure 1]d. Then the roots were coated with three coats of nail varnish except at the tip and allowed to dry. Subsequently, roots were stored in 1% solution of Rhodamine B dye for 1 week. After a week, the roots were rinsed under tap water for 30 minutes and were sectioned bucco-lingually into two halves using a diamond disc (Shofu). Each specimen was then examined for the adaptation of the root-end filling material to the cavity walls, and the extent of dye penetration was evaluated using a stereomicroscope (63X) [Figure 2]a and [Figure 2]b. The depth of dye penetration was measured using the criteria of Tronstad et al., 1983, as follows:
Figure 1: (a) Radiographs of the prepared samples after obturation. (b) Radiographs after the root-end cavity preparation. (c) Radiograph of a sample retrofilled with MTA. (d) Radiograph of a sample retrofilled with Retroplast

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Figure 2: (a) Stereomicroscope view of a sample restored with MTA (63×). (b) Stereomicroscope view of a sample restored with Retroplast (63×)

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  • Score 0: No leakage.
  • Score 1: Marginal leakage not reaching the retrograde cavity floor.
  • Score 2: Leakage all around retrograde filling.
  • Score 3: Leakage deeper than the retrograde cavity floor.

The observations were analysed using SPSS 21.0 and compared with Chi square test at the 0.220 level of significance.

   Results Top

The statistical analysis showed no significant differences among the tested materials. The dye leakage was measured in both the vertical direction (depth) and horizontal direction (lateral spread). When the leakage scores of different depths were compared, 45% of MTA and 30% of Retroplast samples showed marginal leakage not reaching the retrograde cavity floor. There was no statistically significant difference between the two groups regarding the depth of dye penetration. In the horizontal direction, MTA presented a statistically higher leakage percentage (35%) compared with Retroplast (20%) circumferentially of the retrograde filling. Both groups showed no significant differences (P > 0.05) among the leakage scores of the all samples [Table 1] and [Graph 1].
Table 1: Comparison of two different sealing materials (Chi-square test)

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   Discussion Top

Microorganisms play a key role in the development of pulpal and periapical diseases. Teeth with pulpal or periapical pathology have a complex microbial flora consisting of cocci, rods, spirochetes, and fungi. Microbes grow both as planktonic cells or in aggregates and as biofilms. These microbes are difficult to remove completely, and the residual ones are a potential source of re-infection of the previously treated root canals. The complete obliteration of the root canal system by an effective obturation method serves as a barrier to the supply of nutrients to these residual microbes and prevents the development of post-treatment disease or peri-apical pathosis. In post-treatment diseased teeth, Gram-positive microorganisms predominate. When healing is not achieved after non-surgical endodontic therapy and when retreatment is not possible or has failed, the surgical approach is indicated. The procedure routinely consists of the exposure and resection of the involved apex, the preparation of a class I cavity, and the insertion of a root-end filling material. The most commonly used root-end filling materials are amalgam, glass ionomer cement, zinc oxide eugenol cement, and composite resins. Newer materials include MTA and other calcium silicate materials as well as composite-based materials such as Retroplast and Geri-store. The plane of sectioning also affects the degree of microleakage, and the root end resection angle of 90° has been proved to be the most acceptable. Also, the preferred depth of root resection is 3 mm, which eliminates the apical ramifications by 98% and lateral canals by 93%. When non-adhesive materials are used for apical sealing, a microscopic space always exists between the restoration and the tooth which leads to microleakage. The quality of the apical seal obtained by root-end filling materials has been assessed by various methods such as dye penetration, radioisotope penetration, bacterial penetration, electrochemical means, and fluid filtration techniques. The dye penetration method is the most popular and is easily performed. Various dyes that can be used include India ink, basic fuchsin, methylene blue, and Rhodamine B.[11] Researchers stated that methylene blue suffers discoloration when in contact with some alkaline filling materials that cause hydrolysis of methylene blue, resulting in the formation of a clear compound named thionine, leading to false results.[12] In relation to MTA, in the presence of water, calcium oxide in the material could form calcium hydroxide, which would certainly cause discoloration of methylene blue.[13] In this study, a Rhodamine B solution was used because according to Moraes et al.,[14] Rhodamine B is not influenced by alkaline materials. It diffuses greater into human dentin than methylene blue. Rhodamine B dye has been the preferred dye for conofocal microscopy because of its fluorescence. Unlike MTA, Retroplast is not condensed into an apical cavity but applied onto a slightly concave resection surface with the intention of sealing both root canals and exposed dentinal tubules. A successful radiographic healing frequency of 74–92% was reported by Rud et al.[15] after a 6-month to 12-year follow-up period. Andreasen et al.[16] tested the tissue reactions to the retrograde bonded composite fillings in monkeys; a unique healing response with deposition of cementum and insertion of new sharpeys fiber, which entered a newly formed apical lamina dura, was found, indicating that tissue regeneration including cementogenesis may occur on the composite material and consequently form a biological closure of the root canal. P. M. Yazdi et al.[17] evaluated Retroplast for root-end filling in 60 patients (82 roots) with a mean follow-up period of 8 years. A total of 77% of the roots were characterized by complete radiographic healing. The main reason for unsatisfactory healing was displaced or lost Retroplast filling. The results are comparable to the results of previously published long-term studies evaluating materials for root-end filling that indicates that Retroplast used as a root-end filling material is associated with a successful treatment outcome in the majority of cases. Saini et al.[11] showed in their study that all materials exhibited microleakage, but there was significantly less leakage in MTA (0.83 mm) when compared to Miracle Mix (1.39 mm) and GIC (1.32 mm). MTA, however, has certain drawbacks such as difficult handling and a slow setting reaction, which might contribute to leakage, surface disintegration, loss of marginal adaptation, and continuity of the material. Besides, MTA has an alkaline pH and the interaction with the organic phase of dentin results in degradation of type 1 collagen, and the microhardness of dentin is altered.[18] A recent study comparing the sealing ability of different root-end filling materials using the fluid filtration technique, Retroplast was found to be superior to others.[19] In the present study, the microleakage of MTA was comparatively less than that of Retroplast, but there was no significant difference between sealing abilities of both materials.[20] Only 5% of samples of both groups show complete sealing; rest all samples showed dye leakage, although there was leakage deeper than the retrograde cavity floor, with the lowest scored percentage (15%) shown by MTA. This may be because of the formation of the hydroxyapatite-like crystals at the interface between the material and canal wall, because of which the material shows superior adhesion preventing the penetration of the dye and thus showed the least microleakage. Moreover, MTA is hydrophilic, so it undergoes setting expansion when it sets in a moist environment, and thus, the presence of moisture in the surgical field does not affect its setting or the properties. However, there was only 20% of Retroplast samples scored, with leakage all around retrograde filling, which is significantly lesser than MTA (35%).

The comparative sealing ability of composite resin could be explained on the basis that the contraction gaps between composite resin and dentinal walls might have been formed during polymerisation, which might have been sealed by the resin impregnation technique, leading to less microleakage values. Thus, within the limitations of our study, it was concluded that both MTA and Retroplast exhibited microleakage. MTA showed the least scored (leakage deeper than the retrograde cavity floor) percentage value [Table 1]. However, the differences were not statistically significant.

   Conclusion Top

Within the limitations of the present study, the following can be concluded:

  1. Both the materials, Retroplast and MTA, are equally effective in sealing, according to the criteria taken.
  2. Further in vitro and in vivo studies are needed to correlate with the findings of the present study.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Priyanka SR, Veronica A. A literature review of root-end filling materials. Inter J Dent Med Sci 2013;9:20-5.  Back to cited text no. 1
Ozata F, Erdilek N, Tezel H. A comparative sealability study of different retrofilling materials. Int Endod J 1993;26:241-5.  Back to cited text no. 2
Zanza A, D'Angelo M, Reda R, Gambarini G, Testarelli L, Di Nardo D. An update on Nickel-Titanium rotary instruments in endodontics: Mechanical characteristics, testing and future perspective-An overview. Bioengineering (Basel) 2021;8:218.  Back to cited text no. 3
Seracchiani M, Donfrancesco O, Relucenti M, Reda R, Zanza A, Gambarini G, et al. In vitro evaluation of a recently developed rotary file: AF rotary. Braz Dent Sci 2021;24:1-6.  Back to cited text no. 4
Sousa CJ, Loyola AM, Versiani MA, Biffi JC, Oliveira RP, Pascon EA. A comparative histological evaluation of the biocompatibility of materials used in apical surgery. Int Endod J 2004;37:738-48.  Back to cited text no. 5
Holt GM, Dumsha TC. Leakage of amalgam, composite, and Super-EBA, compared with a new retrofill material: Bone cement. J Endod 2000;26:29-31.  Back to cited text no. 6
Torabinejad M, Chivian N. Clinical applications of mineral trioxide aggregate. J Endod 1999;25:197-205.  Back to cited text no. 7
Fogel HM, Peikoff MD. Microleakage of root-end filling materials. J Endod 2001;27:456-8.  Back to cited text no. 8
Niederman R, Theodosopoulou JN. A systematic review of in vivo retrograde obturation materials. Int Endod J 2003;36:577-85.  Back to cited text no. 9
Saunders WP. A prospective clinical study of periradicular surgery using mineral trioxide aggregate as a root-end filling. J Endod 2008;34:660-64.  Back to cited text no. 10
Saini D, Nadig G, Saini R. A comparative analysis of microleakage of three root end filling materials: An in vitro study. Arch Orofac Sci 2008;3:43-7.  Back to cited text no. 11
Wu MK, Kontakiotis EG, Wesselink PR. Discoloration of 1% methylene blue solution in contact with dental filling materials. J Dent 1998;26:585-9.  Back to cited text no. 12
Orosco FA, Bramante CM, Garcia RB, Bernardineli N, de Moraes IG. Sealing ability, marginal adaptation and their correlation using three root-end filling materials as apical plugs. J Appl Oral Sci 2010;18:127-34.  Back to cited text no. 13
Moraes IG, Moraes FG, Mori GG, Gonçalves SB. Influence of calcium hydroxide on dyes for dentin labeling, anlyzed by means of a new methodology. J Appl Oral Sci 2005;13:218-21.  Back to cited text no. 14
Rud J, Rud V, Munksgaard EC. Effect of root canal contents on healing of teeth with dentin bonded resin composite retrograde seal. J Endod 1997;23:535-41.  Back to cited text no. 15
Andreasen JO, Munksgaard EC, Fredebo L, Rud J. Periodontal tissue regeneration including cementogenesis adjacent to dentin-bonded retrograde composite fillings in humans. J Endod 1993;19:151-3.  Back to cited text no. 16
Yazdi PM, Schou S, Jensen SS, Stoltze K, Kenrad B, Sewerin I. Dentine-bonded resin composite (Retroplast) for root-end filling: A prospective clinical and radiographic study with a mean follow-up period of 8 years. Int Endod J 2007;40:493-503.  Back to cited text no. 17
Badr AE. Marginal adaptation and cytotoxicity of bone cement compared with amalgam and mineral trioxide aggregate as root end filling materials. J Endod 2010;36:1056-60.  Back to cited text no. 18
Kumar CA, Arafath MY, Pitchai MS, Kirubanandan S. A comparative evaluation of marginal integrity of retroplast, KETAC-N 100 and gutta percha before and after post space preparation using fluid filtration technique: An in-vitro study. Int J Appl Dent Sci 2017;3:5-15.  Back to cited text no. 19
Adamo HL, Buruiana R, Schertzer L, Boylan RJ. A comparison of MTA, super-EBA, composite and amalgam as root-end filling materials using a bacterial microleakage model. Int Endod J 1999;32:197-203.  Back to cited text no. 20

Correspondence Address:
Dr. Nitin Kararia
93 Arcadia Greens, B Block, Vaishali Estate, Gandhi Path West, Jaipur, Rajasthan
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijdr.ijdr_357_22

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