Intraradicular Smear Removal Efficacy of Triphala as a Final Rinse Solution in Curved Canals: A Scanning Electron Microscope Study.

AIM: This study aimed to compare smear layer removal ability of different solutions of Triphala (TA) when used in specific irrigant protocols in curved canals.
MATERIALS AND METHODS: Seventy-four mandibular first molars with 25-35 degrees of curvature of mesial roots were selected and standardized, and canals were prepared. As the initial rinse solution (8 mL), 5% sodium hypochlorite was used. Samples were divided into control (Group I-normal saline, Group II-17% ethylenediaminetetraacetic acid) and experimental (Group III, IV, V, VI, VII, VIII, and IX) groups based on the type of final rinse solution (5 mL) used, that is, TA-premixed (P), TA-(P)-sonic, TA-(P)-ultrasonic, 3% TA solution, 5% TA solution, 10% TA solution, and 10% citric acid. Samples were dehydrated, split buccolingually, splutter coated, and examined in field emission scanning electron microscope.
RESULTS: Among the experimental groups, Group V presented the least amounts of smear and debris in all thirds of the root canal with mean values of 1.6 ± 0.63 and 1.6 ± 0.62, respectively, and on comparison with Group II the results were comparable, and no significant difference was found statistically (P > 0.05). Group V presented with the highest amount of erosion with loss of peritubular and intertubular dentin at all levels with mean values of 1.60 ± 0.51.
CONCLUSION: The use of TA as a final rinse solution during biomechanical preparation seems promising.

INTRODUCTION

Smear layer was first reported as being made up of particle sizes ranging from less than 0.5 to 1.5 μm.[1] It is a thin layer of grinding debris with an overall thickness of 2–5 μm, extending a few micrometers into dentinal tubules.[2] The process of preparation of the canal can force components of smear into dentinal tubules for varying distances, resulting in formation of smear plugs.[3] Smear layer was found to have two components: the superficial smear layer and the smear layer material that was packed into the dentinal tubules for a depth of up to 40 μm.[4] As a result of adhesive forces between dentinal tubules and smear along with capillary action, smear was pushed up to a depth of 110 μm when surface active agents were used within.[56] Various methodologies have been suggested for intraradicular smear removal.[78] Various synthetic chemical substances have been used as endodontic irrigants for their effectiveness in removal of smear and disinfection, but also have undesirable properties such as toxicity and allergic potential. There is an increase in evaluation and use of natural herbal substances as a part of dental treatment procedures due easy availability, cost-effectiveness, and being more biocompatible. The gradual increase in resistant strains to antibiotics, the side effects caused by the advent of synthetic drugs, and the perils associated with irrigants such as sodium hypochlorite have impelled researchers to look for safer and biocompatible patient-friendly herbal alternatives.

Triphala, an Ayurvedic herbal formulation comprises dried, powdered fruits of three medicinal plants Terminalia bellerica, Terminalia chebula, and Emblica officinalis. It has tannic acid as its principal constituent. It has been used in Indian traditional medicine for treatment of headaches, constipation, and hepatic disorders.[9] Initial studies have shown bacteriostatic or bactericidal effect of tannic acid on gram-positive and gram-negative pathogens. The advantages of Triphala include easy availability, low cost, long-term substantivity, less toxicity, and absence of microbial resistance.[10] Compared to many commonly used root canal irrigants, triphala is safe and is composed of compounds with proper physiologic effects in addition to its anti-oxidative and anti-inflammatory properties.[11]

MATERIALS AND METHODS

One hundred and fifty extracted human permanent mandibular first molars were collected, cleaned, and teeth devoid of cracks, defects, restorations, and endodontically treated were separated and analyzed using radiography. Those teeth with mature, intact root apices were selected. Two roots were separated after access, distal wall was covered with composite, and mesial roots with a curvature of 20°–35° were selected, dried, and coded; apical third of the root was covered with wax and embedded in transparent plastic cups filled with soft polyvinyl siloxane. The aim was to prevent irrigants from extruding the apex in order to simulate in vivo closed apex conditions.

The samples were then randomly divided into 2 control groups (n = 5) and 10 experimental groups (n = 8) [Table 1]. The instrumentation was initiated with hand files up to size 20 followed by Protaper rotary files from size S1 to F2 (Dentsply, Maillefer, Ballaigues, Switzerland) as per manufacturer instructions. One milliliter of the irrigant was used for canal irrigation after using each instrument and before proceeding to the next. A total of 8 mL of the irrigant was used during biomechanical preparation procedure. The samples were then irrigated with a final rinse of 5 mL of irrigant solution as per the respective group for 3 minutes. The irrigant was delivered using a 28-gauge side vent ProRinse needle (Dentsply, Tulsa Dental) at the working length.

Table 1

Irrigant grouping

Groups (n = 5–8)	Initial rinse	Final rinse
I—Negative control (n = 5)	Normal saline	Normal saline
II—Positive control (n = 5)	5% NaOCl	17% EDTA
III	5% NaOCl	Triphala premixed
IV	5% NaOCl	Triphala premixed (Sonic activation)
V	5% NaOCl	Triphala premixed (Ultrasonic activation)
VI	5% NaOCl	3% Triphala in 10% DMSO
VII	5% NaOCl	5% Triphala in 10% DMSO
VIII	5% NaOCl	10% Triphala in 10% DMSO
IX	5% NaOCl	10% citric acid
X	5% NaOCl	10% DMSO

DMSO = dimethyl sulfoxide, EDTA = ethylenediaminetetraacetic acid, NaOCl = sodium hypochlorite

The needle was withdrawn 5 mm, inserted back to working length followed by rotation of needle by 180° three times alternatively for the first minute of irrigant delivery. During the second minute, an F2-size Gutta-Percha cone (Dentsply Maillefer, Ballaigues, Switzerland) was inserted to working length and withdrawn six times (manual dynamic activation). This was performed to improve the irrigant delivery and replacement to the apical third of the canal space. The irrigant was activated using sonics, ultrasonics, or left alone for the third minute as per the final rinse protocol for the respective groups. Sonic activation was performed using an EndoActivator unit (Dentsply Maillefer, Ballaigues, Switzerland) with the tip at 2-mm short of working length and activated for 20 seconds 3 times intermittently. Passive ultrasonic activation was performed with an Endosonic EMS unit with the tip at 2 mm short of working length and activated intermittently for 20 seconds.

After the completion of 5 minutes, a post-final rinse irrigation of 10 mL of distilled water was performed. The teeth were then carefully split longitudinally in a buccolingual plane using a diamond disc dividing them into two halves and for each tooth; the half containing the most visible part of the apex was selected, coded, and stored. The teeth were then placed in a 10% neutral buffered formalin solution at 18°C for 24 hours. They were then post-fixed in osmium tetroxide (1% w/v) for 2 hours before being dehydrated in graded solutions of Isopropyl alcohol (Nice Chemicals Ltd, Cochin, Kerala, India). Separation markings of 5 mm were made for the apical, middle, and coronal thirds, respectively on the split half of the root using a custom marker. The prepared samples were then placed in ultraviolet sterilization chamber and stored in sterile pouches. The coded samples of each group were mounted on aluminum stubs with carbon tape (Royal tapes Pvt Ltd, Chennai, India) with the entire root canal visible and facing upwards. Each of the specimens was coated with a 20–30 nm thin layer of gold in a gold sputter coating machine (Quorum, United Kingdom). The samples were then examined using a field emission scanning electron microscope with a high resolution (SIGMA 0336 FESEM, ZIESS, Munchen, Germany). The photo micrographs were obtained at ×2000 magnification using digital image analysis software and stored appropriately for subsequent analysis. The most representative micrographs were taken for each millimeter of the specimen and were recorded for apical, middle, and coronal thirds, respectively. The results that were scored by the independent operators were compared and tabulated for their respective score values of smear layer, debris, and erosion in the apical, middle, and coronal thirds of the root canal. The smear, debris, and erosion were evaluated using the criteria developed by Caron et al.,[12] Dadresanfar et al.,[13] and Torabinejad et al.,[14] respectively.

RESULTS

The coronal third presented least amount of smear with a mean value of 2.04 ± 1.50 followed by the middle third with a mean value of 3.03 ± 1.51, and the most amount of smear was in the apical third of the canals with a mean value of 3.48 ± 1.19 [Chart 1].

Chart 1

Average smear scores

Among the experimental groups, Group V presented the least amount of smear and debris [Chart 2] in all thirds of the root canal with mean values of 1.6 ± 0.63 and 1.6 ± 0.62, respectively. In this study, overall Group VI presented the least amounts of erosion among experimental groups at all levels with a mean value of 1.0 ± 0.00000 [Chart 3]. Group V is efficient in removal of smear and debris, and on comparison with Group II, the results were comparable, and no significant difference found statistically (P > 0.05) [Charts 4 and 5].

Chart 2

Average debris scores

Chart 3

Average erosion scores

Chart 4

Mean scores: apical, middle, and coronal

Chart 5

Overall mean scores

DISCUSSION

Endodontic therapy aims to eliminate microbial colonization and achieve a three-dimensional obturation of the root canal system. The main reason for a large number of treatment failures is persisting infections within these canal spaces. Irrigant solutions coupled with biomechanical preparation have been effectively used to achieve this objective [Figure 1]. This becomes more difficult in teeth with curved canals where instrumentation and irrigant replacement at the apex become more difficult. Several studies have highlighted the undesirable effect of these irrigant solutions on biological tissues.[15] The eradication of smear layer significantly improves the apical and coronal seal of obturated root canal system.[16] There is a need for using safer materials as irrigating solutions during endodontic procedures. A number of herbal products have been tried as irrigant solutions. This study used and evaluated Triphala as a final rinse irrigation solution. With changes in lifestyle and treatment modalities, the pathogens are also becoming more resistant. The significance of the naturopathy and herbal drugs comes to play a role in these circumstances as they have a benefit of being safe, biocompatible, and nontoxic. Many herbal medicines have a potential use in endodontics. This study was conducted in curved mesiobuccal canal of the mesial roots of the mandibular first molar tooth where curvature and canal preparation was standardized. A premixed Triphala solution by the manufacturer was used and compared with custom prepared Triphala solutions of 3%, 5%, and 10%. On statistical analysis of the groups III, IV, and V, and the groups VI, VII, and VIII, there was a significant difference (P < 0.05) [Figures 2 and 3].

Figure 1

Image comparison - Group I and II

Figure 2

Image comparison - Group III, IV, and V

Figure 3

Image comparison - Group VI, VII, and VIII

The contribution of plant extracts and polyherbal preparations in treating different ailments has been documented. Polyherbal drugs have a synergistic effect and have played a role in restoring and rejuvenating the immune system. The Indian Council of Medical Research has conducted controlled clinical trials for herbal-derived medication.[17] Triphala extract used as an oral rinse solution was very effective in reducing gingival inflammation with no side effects.[18] Triphala has been shown to have good antimicrobial properties and can be considered for use as an irrigating solution during endodontic therapy. Biofilms offer more resistance to antimicrobial agents compared to planktonic bacteria, and triphala has been shown to be effective against the biofilms of Enterococcus faecalis. It has been found to have antifungal properties also.[1920]

Triphala is a highly efficacious polyherbal Ayurvedic medicine consisting of fruits of the plant species E. officinalis (Amalaki), T. bellerica (Bibhitaki), and T chebula (Haritaki). Triphala formulations contain various ingredients such as tannins, quinones, flavones, flavonoids and flavonols, gallic acid, and vitamin C, which contribute toward their pharmacological actions and their effect on human physiology.[21] Triphala is also a very good chelating agent because of the fruits that are rich in citric acid and holds promise in the removal of smear layer.[22]

Tannic acid represents the major constituent of Triphala and has been reported by other studies to possess bacteriostatic and bactericidal actions toward some gram-positive and gram-negative pathogens. Human physiological activities such as phagocytic cell stimulation, host-mediated tumor, and anti-infective actions have been attributed to them. They complex with proteins through nonspecific forces of hydrogen bonding, covalent bond formation, and hydrophobicity. Their mechanism of action is due to their ability to deactivate microbial adhesins, cell envelope transport proteins, and enzymes.[23]

Quinones are highly reactive substances. Vitamin K is a naphthoquinone with antihemorrhagic activity. They provide free radicals and irreversibly complex with protein and cause functional loss. They act on the cell wall and render substrates unavailable. Flavonoids are synthesized in response to a microbial infection by plants. They are antimicrobials complex with extracellular proteins and bacterial cell walls causing antimicrobial action. Lipophilic flavonoids disrupt microbial membranes. They inhibit Vibrio cholera, Shigella, and Streptococcus mutans in vitro. They reduce incidence of fissural caries. Gallic acid is present in all constituents of Triphala. It has hepatoprotective and antioxidant activity and suppresses cancer cells growth. Vitamin C and bioflavonoids helps to accelerate the healing process. Fruit juice of E. officinalis has the highest vitamin C content and contributes to 45–70% of the antioxidant nature of triphala. Triphala stimulates neutrophil function and conditions of stress, prevents increase of interleukin-4 levels, and corrects decreased interleukin-2 and Interferon-γ levels. Its immunosuppressive activity under conditions of stress is due to inhibitory action on complement system, humoral immunity, cell-mediated immunity, and mitogen-induced T-lymphocyte proliferation. The extracts of the individual components of Triphala enhance the macrophage activation due to free radical scavenging action and neutralizes reactive oxygen species. It is a potential immunostimulant and has the potential for being an alternative for allopathic immunomodulators.[24] Chebulinic acid impedes vascular endothelial growth factor (VEGF) by suppressing VEGF receptor-2 phosphorylation. This material being nontoxic and cost-effective can be used effectively in conditions requiring VEGF suppression.[25] The extract of T. chebula plant hinders formation of dental plaque. It hampers the sucrose-induced adherence and glucan-induced aggregation, which help colonization of microbes on surface of the teeth. This prevents the accumulation of acids on tooth surface and prevents demineralization and the disintegration of enamel.[26] Triphala was found to be as effective in its antibacterial efficacy against E. faecalis as sodium hypochlorite.[27] Triphala solution in 10% dimethyl sulfoxide has good antibacterial effectivity and can also be employed as an root canal irrigant in permanent teeth.[2829] It can be effectively used to manage dental caries, gingival disease, periodontal disease, and oral candida infections, and further it can also be utilized as a root canal irrigant in endodontics.[30]

In this study, Group V Triphala was very effective and was nearly as efficient in removal of smear when compared to Groups II at the coronal and apical thirds whereas in the middle third it was comparable to Groups II and IX. On statistical comparison and analysis, there was no significant difference between Group II, V, and VIII (P > 0.05) [Figure 4].

Figure 4

Image comparison - Groups II, V, and VIII

Discoloration of the tooth was observed when commercial preparations of herbal irrigants were used in endodontics. This may be due to added coloring agent in the commercial products or due to natural color pigments in Triphala juice and needs to be further investigated. These herbal irrigants also produced discoloration of gloves and were slightly viscous and sticky.[31]

The use of herbal alternatives such as Triphala as a root canal irrigant is advantageous as it avoids the side effects of synthetic chemicals. Triphala has strong inhibitory activity collagenases and matrix metalloproteinases, which can cause periodontal destruction. Inhibition of these enzymes is performed to arrest this destruction. For collagenase inhibition, doxycycline has been successfully used. Side effects of synthetic drugs can be avoided by herbal derivatives. Synthetic chemical substances formulated as solutions for use as irrigants in endodontics help in disinfection and cleansing of the canal system, but carry along with them undesirable properties such as toxicity, allergic potential, unacceptable taste, and cost factor. There is awareness and a major drift in trend toward the use of native herbal medicines with the right pharmacological properties due to less toxicity and cost-effectiveness.[3233]

CONCLUSION

Within the limitations and protocols used in this study, the use of triphala as a final rinse solution during endodontic therapy seems promising.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.