|Year : 2022 | Volume
| Issue : 2 | Page : 86-90
Confocal laser scanning microscopic evaluation of sealing ability of bone cement, mineral trioxide aggregate and biodentine as root-end filling materials: An in vitro study
Shalin Ann Saji1, Tony Mathew1, Aditya Shetty1, Gurmeen Kaur2, Sunheri Bajpe1
1 Department of Conservative Dentistry and Endodontics, AB Shetty Memorial Institute of Dental Sciences, Nitte (Deemed to be University), Mangalore, Karnataka, India
2 Department of Conservative Dentistry and Endodontics, Dr. D. Y. Patil Dental College and Hospital, Dr. D. Y. Patil Vidyapeeth, Pune, Maharashtra, India
|Date of Submission||09-Nov-2021|
|Date of Decision||25-Dec-2021|
|Date of Acceptance||17-Jan-2022|
|Date of Web Publication||01-Jul-2022|
Dr. Tony Mathew
Department of Conservative Dentistry and Endodontics, AB Shetty Memorial Institute of Dental Sciences, Nitte (Deemed to be University), Mangalore, Karnataka
Source of Support: None, Conflict of Interest: None
Aim: To compare the sealing ability of polymethylmethacrylate (PMMA) bone cement, mineral trioxide aggregate (MTA), and Biodentine as root-end filling materials by assessing the degree of microleakage through confocal laser scanning microscopy.
Materials and Methods: Thirty extracted maxillary incisors were root canal treated using the rotary ProTaper system. Apical root resections followed by retrograde cavity preparation were done. The teeth were divided into three groups and filled with the 3 tested materials (PMMA bone cement, MTA, and Biodentine). Samples were coated with nail varnish, immersed in 0.5% aqueous solution of rhodamine B dye for 24 h, and rinsed with water to remove excess dye. Samples were horizontally sectioned at 1 mm intervals into three using a diamond disk and were labeled A, B, and C and considered first, second, and third, respectively, based on their distance from the apex. Each slice was divided into four equal parts and evaluated using a confocal laser scanning microscope. Dye penetration was scored based on the amount of microleakage. The data were analyzed using one-way analysis of variance.
Results: Intergroup comparison of the mean scores of dye penetration among the three materials showed that there is a statistical difference between PMMA bone cement, MTA, and Biodentine, in sections B and C (P ≤ 0.05). The three groups showed no statistical difference in dye penetration scores in section A.
Conclusion: The microleakage is least with PMMA bone cement followed by Biodentine and MTA. Microleakage was least in section C followed by sections B and A.
Keywords: Biodentine, bone cement, confocal laser scanning microscope, microleakage, mineral trioxide aggregate, root-end filling
|How to cite this article:|
Saji SA, Mathew T, Shetty A, Kaur G, Bajpe S. Confocal laser scanning microscopic evaluation of sealing ability of bone cement, mineral trioxide aggregate and biodentine as root-end filling materials: An in vitro study. Endodontology 2022;34:86-90
|How to cite this URL:|
Saji SA, Mathew T, Shetty A, Kaur G, Bajpe S. Confocal laser scanning microscopic evaluation of sealing ability of bone cement, mineral trioxide aggregate and biodentine as root-end filling materials: An in vitro study. Endodontology [serial online] 2022 [cited 2022 Aug 17];34:86-90. Available from: https://www.endodontologyonweb.org/text.asp?2022/34/2/86/349565
| Introduction|| |
The main goal of root canal treatment is to clean and shape the root canal system and obtain three-dimensional obturation. In case of failure of nonsurgical endodontic treatment, surgical endodontic therapy is indicated. It involves exposure of the apex, root-end resection, and preparation followed by insertion of root-end filling material. The presence of lateral canals and ramifications at the apical end of the root renders the root canal system very complex making it difficult in achieving complete debridement. As a result, an orthograde technique cannot be used in all clinical scenarios to treat root canals.
The purpose of a root-end filling is to prevent irritants from the root canal from leaking into the periapical region and to improve the apical seal created by nonsurgical endodontic treatment. Various restorative materials used for coronal restorations have been investigated as root-end filling materials, as well as restorative materials especially for root-end filling have been developed. An ideal retrograde filling material should adapt well to the root canal walls to obtain a tight seal, it should be radio-opaque, dimensionally stable, nontoxic, well tolerated by the periradicular tissues. It should also be able to induce healing, easy to manipulate, nonabsorbable, and be unaffected by the presence of moisture. These are the requirements for the success of surgical endodontics.
Various studies have proved mineral trioxide aggregate (MTA) as the best among all root-end filling materials. However, MTA has been criticized concerning the requirements of an ideal root-end filling material in two regards-difficult to handle, very slow setting reaction which might contribute to leakage, surface disintegration, and loss of marginal adaptation of the material.
Studies suggest that Biodentine could be an efficient alternative root-end filling material because of its physical, biological, and handling properties. Biodentine has dentine-like mechanical properties, fulfills the requirements for a suitable root-end filling material in that it exhibits biocompatibility, long-term sealing of the cavity, antimicrobial properties, and the ability to induce hard tissue regeneration; it is also stable, insoluble, hydrophilic, and easy to handle.
One of the new materials that might potentially provide the necessary properties of a root-end filling material is polymethylmethacrylate (PMMA) bone cement. Bone cement has been widely used in orthopedic surgery. Bone cement was approved for use in hip and knee prosthetic fixation by the US Food and Drug Administration in the 1970s. While bone cement has become widely utilized for securing the prosthesis to living bone since then, the trends in its utilization have changed. The characteristics of bone cement make it suitable as a root-end filling material.,
This study aimed to compare the sealing ability of PMMA bone cement, MTA, and Biodentine as root-end filling materials by assessing the degree of microleakage through confocal laser scanning microscopy. Literature suggests that MTA and Biodentine possess favorable properties to be considered as root-end filling materials. None of the studies so far have compared the sealing ability of MTA and Biodentine with PMMA bone cement, which is commonly used for orthopedic surgeries.
| Materials and Methods|| |
Institutional ethical clearance was obtained (ABSM/EC/130/2021 dated 22/03/2021).
Thirty freshly extracted intact, human maxillary incisors were collected and disinfected. The samples were decoronated using a diamond disk and root canals were cleaned, shaped, and obturated with gutta-percha and AH Plus sealer. The apical 3 mm of the root tips were removed perpendicular to the long axis of the tooth with a 556 bur in high-speed handpiece under water spray. A 3 mm deep root-end cavity was prepared on each resected root end using a 170 L fissure bur. The samples were divided into three groups (n = 10) and the cavities were filled with PMMA bone cement, MTA, and Biodentine and stored in 100% humidity at 37°C for 48 h.
Dye penetration test
Samples were coated with nail varnish (except the apical 3 mm), immersed in a 0.5% aqueous solution of rhodamine B dye for 24 h, and rinsed with water for 15 min to remove excess dye. Each sample was then horizontally sectioned at 1 mm intervals into 3 using a diamond disk. The sections resulting in three slices were labeled A, B, and C and considered first, second, and third, respectively, based on their distance from the apex. Each slice was divided into four equal parts and evaluated using a confocal laser scanning microscope [Figure 1]. Dye penetration was recorded and scored 0, 1, 2, 3, or 4 based on the amount of microleakage.
|Figure 1: Confocal laser scanning microscopic images of three groups from sections A, B, and C from the apex|
Click here to view
Intergroup comparison was done using one-way analysis of variance (ANOVA) at a level of statistical significance set at 95% (P < 0.05). Data were analyzed by IBM SPSS-Statistics, version 25.0 (Armonk, NY, USA: IBM CORP).
| Results|| |
The highest mean scores of dye penetration based on the amount of microleakage was seen in MTA while the PMMA bone cement showed the lowest mean scores in section A (3.7000 ± 0.4830), section B (1.6000 ± 0.5164), and section C (0.2000 ± 0.4216) [Table 1]. Compared to MTA and Biodentine, the PMMA bone cement has exhibited the least dye penetration in all three sections from the apex. The mean microleakage scores for PMMA bone cement, MTA, and Biodentine is demonstrated.
|Table 1: Mean scores of sealing ability for different materials in each section from the apex|
Click here to view
Intergroup comparison of the mean scores of dye penetration among the three materials showed that there is a statistically significant difference between PMMA bone cement, MTA, and Biodentine in sections B and C (P ≤ 0.05) [Table 2]. None of the groups showed a statistically significant difference in dye penetration scores in section A. The microleakage is least with Group I (PMMA bone cement) followed by Group III (Biodentine) and Group II (MTA), with section A showing the greatest microleakage followed by sections B and C.
|Table 2: Intergroup comparison of mean scores in each section from the apex between the three materials using one-way analysis of variance|
Click here to view
| Discussion|| |
The placement of a root-end filling material after apicoectomy helps to establish an effective barrier between the root canal and the periapical tissues when an orthograde seal could not be achieved. An ideal root-end filling substance would adhere to the walls of the root end preparation, prevent microbes and their toxins from leaking into the periradicular tissues, be biocompatible, insoluble in tissue fluids, dimensionally stable, and unaffected by moisture.,,
The apical seal of root-end filling materials is one of the major determinants for the predictable outcome in surgical endodontics. Root-end filling materials, unlike orthograde root canal filling materials, come into direct contact with vital periapical tissues. As a result, the tissue reaction to these materials becomes crucial and may influence the surgical endodontic treatment outcome. Cementum deposition on the severed root face is seen as a desirable healing reaction and a need for the restoration of a functioning periodontal attachment. The deposition of cementum starts from the root end circumference and proceeds centrally toward the resected root canal. A “biological seal” is created by the cementum whereas a “physical seal” is provided by the root-end filling, thereby creating a “double seal.”
Various materials such as amalgam, gold foil, ZOE cement, Super EBA, GIC, composite resin, and several newly introduced materials have been used as root-end filling materials. In the present study, PMMA bone cement, MTA, and Biodentine are used as root-end filling materials.
PMMA bone cement is available as a liquid MMA monomer and a powered MMA-styrene co-polymer. The liquid monomer polymerizes around the pre-polymerized powder particles to generate hardened PMMA when the two components are combined. Certain active compounds, such as antibiotics, can be added to the powder component of bone cement which has shown to be very beneficial. As a result, bone cement functions as a modern drug delivery system, delivering the essential medications straight to the surgical site sufficient to kill the bacteria left behind. On the other hand, because the amount of antibiotics that enter the blood is limited, there is a reduced risk of a general allergic reaction to antibiotics. PMMA bone cement used in the current study has gentamycin as one of its constituents which could be advantageous in eradicating persistent periapical infections.,
The exothermic reaction of PMMA bone cement is one of its drawbacks. Due to the minimal amount required in root-end fillings, the exothermic reaction during its setting appears to have no deleterious effects. Another issue is the residual methylmethacrylate monomer. Various research on the effect of free monomer on tissue, on the other hand, has demonstrated minimal toxicity. Bone cement has mostly been investigated concerning its usage in medicine; it appears to have no detrimental consequences, even when used in high quantities during total hip arthroplasty. This claim is backed up by research and a 20-year track record in surgical applications. The quantity required for endodontic cases is substantially lower than those necessary in orthopedics. The smaller amounts needed would result in a significantly lower exothermic reaction and a smaller amount of liberated monomer. As a result, bone cement could be switched from medical to dental use.
Other investigations revealed that bone and bone cement were long-term compatible, allowing excellent interlocking of the cement with the soft and hard tissue of bone without causing bone necrosis. The results of the present study show that bone cement had the least microleakage which could be attributed to its excellent interlocking property. In addition, using an agarose diffusion approach on a cultivated cell monolayer, High and Russell investigated the cytotoxicity of amalgam vs bone cement in cell culture research and proved that bone cement exhibited low cytotoxicity.,,
The bone cement could also withstand a moist environment and is unaffected by blood contamination, having excellent handling properties, allowing it to be easily molded into a dough form and inserted in the root end cavity area.
The other two materials employed in the present study were MTA and Biodentine. MTA has been investigated and used as a retrograde filling material since its introduction. Despite its excellent physical, biological, and hydrophilic qualities, MTA has some drawbacks, including a long setting time, difficulty in manipulation, and high cost.
Biodentine has a similar composition as MTA. It comes with a predosed capsule formulation for use in a mixing device, which helps to improve the material's physical qualities and make it easier to use. Because the setting is faster than MTA, there is a lower possibility of bacterial contamination. Biodentine is a calcium silicate-based cement that sets quickly. It is bioactive, biocompatible, and has excellent sealing qualities, making it suitable for dentin replacement. In the present study, Biodentine has shown less microleakage when compared to MTA. This could be attributed to the tag formation of Biodentine, as demonstrated in the study conducted by Han and Okiji where tag formation was higher in Biodentine than MTA which may enhance the sealing ability.
There are different methods to assess the sealing ability of root-end filling materials. Various techniques, such as dye penetration, radioisotope penetration, bacterial leakage analysis, fluid filtration, and others, can be used to evaluate the apical seal achieved by root-end filling materials. Dye penetration is one of the most widely used methods for determining the sealing ability of root-end filling materials. It has the advantage of being simple to conduct and cost-effective.
Various dyes such as India ink, basic fuchsin, silver nitrate, methylene blue, and Rhodamine B ann be used to assess microleakage. In the present study, 0.5% rhodamine B, a fluorescent dye was used as in normally visible dye, results may vary based on the light quality which makes the detection of dye difficult. It can be easily detected due to the unique fluorescence. As a result, there is no need to look for the dye; it will appear on its own. This luminous dye is also far more sensitive than a conventional dye. Another advantage of Rhodamine B dye over methylene blue (one of the most widely used dyes) is that its molecules are smaller and more surface-active.
The present study employed Confocal Laser Scanning Microscopy to assess the degree of microleakage. This method provides advantages over other traditional techniques such as scanning electron microscopy or transmission electron microscopy. The advantages of this technique include the elimination of out-of-focus blur in images as well as the ability to create three-dimensional images that disclose more accurate information than two-dimensional images.
The current study performed transverse sectioning of the samples to avoid the drawbacks of longitudinal sectioning which includes the random nature of selecting the cut axis and the extremely low odds of sections being cut through the deepest dye penetration site, resulting in underestimation of leakage and achieving unreliable data.
According to the findings of this investigation, bone cement appears to be a suitable material for use as a root-end filling material.
Further long-term clinical studies are mandatory to confirm and evaluate these results and their significance to the treatment outcome. In addition, the current study was performed in-vitro, so the results may vary if it is conducted in-vivo as there are many factors to be considered in the oral environment which may affect the properties of the materials used.
| Conclusion|| |
Within the limitations of the present study, it can be concluded that all materials showed microleakage when assessed under the confocal laser scanning microscope for dye penetration. However, the least microleakage was demonstrated when PMMA bone cement was used as a root-end filling material.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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