| Abstract|| |
Background: A successful root canal treatment involves the elimination of microorganisms, and prevents them from reinfecting the root and/or peri-radicular tissues. This can be mainly achieved by efficient cleaning and shaping of the root canal system. Due to the complexity of the root canal morphology, hand and rotary files cannot clean areas such as the isthmuses and lateral canals. In such cases, effective irrigation and the use of intracanal medicaments are essential. Medicaments that are applied should be removed before obturation. Aim: To evaluate the efficacy of passive ultrasonic irrigation in the removal of three different intracanal medicaments – Triple antibiotic paste (TAP), Odontopaste, and Metapex using a stereomicroscope. Methodology: A total of 45 single-rooted human teeth were selected and decoronated. The root canals were shaped with ProTaper rotary files. The specimens were fixed in modified Eppendorf vials with silicone material. The roots were split longitudinally, and a standardized groove was prepared in the apical part. The teeth were randomly divided into three groups each containing 15 samples based on the intracanal medicament used: TAP, Odontopaste, and Metapex. The root halves were reassembled with sticky wax and remounted in the Eppendorf vial. Each specimen was irrigated with 3% NaOCl and agitated using a passive ultrasonic device. The root segments were disassembled. Digital images were obtained using a stereomicroscope. Results: The data were evaluated statistically using Kruskal–Wallis and Mann–Whitney U tests. There was a statistically significant difference in the remaining intracanal medicament score (P < 0.05). Conclusion: Odontopaste showed the least remaining amount score, whereas TAP and Metapex showed greater retention within the dentin.
Keywords: Calcium hydroxide, corticosteroid, disinfection, intracanal medicament, Metapex, Odontopaste, passive ultrasonic irrigation, triple antibiotic paste
|How to cite this article:|
Shakapuram G, Pachalla MS, Karne AR, Shiva S, Deepa J, Kommineni S. Efficacy of passive ultrasonic irrigation in the removal of three different intracanal medicaments - An in-vitro study. Indian J Dent Res 2021;32:390-4
|How to cite this URL:|
Shakapuram G, Pachalla MS, Karne AR, Shiva S, Deepa J, Kommineni S. Efficacy of passive ultrasonic irrigation in the removal of three different intracanal medicaments - An in-vitro study. Indian J Dent Res [serial online] 2021 [cited 2022 May 26];32:390-4. Available from: https://www.ijdr.in/text.asp?2021/32/3/390/338137
| Introduction|| |
The oral cavity exhibits a complex microbial ecosystem. Infected root canals share this complex microbial system and exhibit a unique niche for development and multiplication. The success of root canal treatment depends on correct chemo-mechanical preparation i.e., the root canal instrumentation must be accompanied by irrigation. Although instrumentation supported by irrigation reduced the number of microorganisms in the infected root canal, the eradication of microorganisms from canal irregularities is enhanced by intracanal medicaments that prevent the proliferation of residual strains, as well as recontamination.
Intracanal medicaments are defined as the antiseptic agents in the chemical form applied to the walls of the root canals with the objective of eliminating microorganisms present before or even after cleaning and irrigating the root canal system. The need for intracanal medication increases in those cases where bacteria are resistant to routine treatment, and where the therapy cannot be successfully completed due to the presence of pain or continuing exudates. Bacteria in infected root canals may proliferate and invade ramifications, apical deltas, isthmuses, and dentinal tubules. In these areas, bacteria remain unaffected by biomechanical preparation and may result in persistent endodontic infections. Therefore, the use of intracanal medicaments is essential to eliminate bacteria that remain after mechanical debridement.
According to Grossman, an ideal intracanal medicament should be an effective anti-microbial agent with prolonged antimicrobial effect, be non-irritating to the periapical tissue, be active in the presence of blood, serum, and protein derivatives of tissue, should not stain tooth structure nor induce a cell-mediated immune response.
No single intracanal medicament fulfils all these requirements. Hence, combinations of intracanal medicaments are being used to fulfill most of the ideal requirements.
In the present study, three such intracanal medicaments are used
- Antibiotic based – Triple Antibiotic Paste (TAP)
- Corticosteroid based – Odontopaste
- Calcium hydroxide based – Metapex.
The infection of the root canal system is considered to be polymicrobial, consisting of both aerobic and anaerobic bacteria. Because of the polymicrobial nature, it is unlikely that any single antibiotic could result in effective sterilization of the canal. The combination that appears to be most promising consists of metronidazole, ciprofloxacin, minocycline (TAP).
Since its introduction in 1920 (Hermann 1920), calcium hydroxide has been widely used in endodontics. It has various biological properties such as antimicrobial activity, high alkalinity, inhibition of tooth resorption and tissue dissolving ability. Because of all these properties, calcium hydroxide has been recommended to be used as an intracanal medicament. To further improve its properties, calcium hydroxide was mixed with other substances. Such additional substances either act as vehicles that can speed up or slow down ionic dissociation or aid the filling of the pulpal cavity by means of their consistency or enhanced antimicrobial action and some of them enhance radiopacity. Metapex, a silicone oil–based calcium hydroxide paste containing 38% iodoform is very popular.
Corticosteroid-based medicaments act on the synthesis of lipocortin and vasocortin, inhibiting the formation of edema and A2 phospholipase enzymes. Once inhibiting this enzyme, membrane phospholipids cannot be converted into arachidonic acid. Therefore, the cyclo-oxygenase and lipo-oxygenase are blocked. A recently developed corticosteroid-based antibiotic containing paste is Odontopaste. It contains 1% triamcinolone acetonide and 5% clindamycin, 0.25%–0.75% calcium hydroxide, and purified water.
Before obturation, the canal space must be thoroughly debrided of the intracanal medicament as residual medicament can negatively influence the outcome of obturation.
In vitro studies have shown that remnant calcium hydroxide can:
- Hinder the penetration of sealers into the dentinal tubules
- Markedly increase the apical leakage of root canal–treated teeth, and potentially interact with zinc oxide eugenol sealers and make them brittle and granular.
TAP should be removed to avoid an effect on sealer penetration and tooth discoloration. Also, it has been shown that antibiotic pastes had a detrimental effect on human stem cells in the apical papilla.
Nevertheless, the complex root canal anatomy with many canal irregularities may be inaccessible for conventional irrigation procedures, and intracanal medicaments may remain in these extensions such as fins and isthmuses. Effective irrigant delivery and agitation are prerequisites to promote root canal disinfection and debris removal and improve successful endodontic treatment. The ultrasonic activation of sodium hypochlorite still remains the gold standard on chemical, biological, and physical debridement of the root canal system. Hence, in the present study, a passive ultrasonic irrigation technique was used for the removal of intracanal medicament.
In this in vitro study, a stereomicroscope was used for the visualization of the remaining intracanal medicament in the groove.
Until now, no research has been conducted on the removal of these three intracanal medicaments. Therefore, the purpose of this in vitro study was to evaluate the efficacy of passive ultrasonic irrigation in the removal of three different intracanal medicaments – Triple antibiotic paste, Odontopaste, and Metapex, using the stereomicroscope.
| Materials and Methods|| |
A total of 45 freshly extracted human maxillary incisor teeth were collected for the study. The teeth were cleaned using an ultrasonic scaler to render them free from calculus and tissue tags. The teeth were stored in 10% formalin solution until required. Criteria for tooth selection included: Single rooted teeth with a single patent root canal, with intact root apex, and with no visible root caries. Teeth with cracks, resorption, and dilacerations were excluded from the study.
Radiographs of all the teeth were exposed from facial and proximal views to confirm the presence of a single canal. The coronal portions were decoronated at the cementoenamel junction with a diamond disc underwater coolant to standardize roots length to 13 mm using digital vernier calipers. A size 15 K-file was introduced into each canal until it could be seen through the apical foramen to ensure apical patency as well as to determine the working length (W.L) until it was visible at the apical foramen. The W.L was reestablished by deducting 1 mm from this measurement. The size of the canal was standardized such that a 20K file could bind at the working length.
ProTaper instruments were used according to the manufacturer's instructions using a gentle in-and-out motion. The instrument sequence was SX at two-thirds of the W.L; S1 and S2 at 1 mm short of working length; and then F1(20.07), F2(25.08), F3(30.09), F4(40.06), and F5(50.05) up to the WL. Once the instrument has negotiated to the end of the canal and had rotated freely, it was removed. After each instrument, 2 mL of 3% NaOCl was used as an irrigant.
After instrumentation, the specimens were fixed in modified Eppendorf vials with silicone material. After removal from the impression material, the roots of all teeth were grooved longitudinally on the buccal and lingual surfaces with a diamond disc under copious water irrigation, avoiding penetration into the root canal. Then, the roots were split into two halves with a small chisel. A longitudinal groove of 3 mm long, 0.4 mm wide, and 0.5 mm deep was then cut in the root canal wall of one-half of each tooth at a distance of 2–5 mm from the apex to simulate an uninstrumented canal extension in the apical region. A toothbrush was used to remove debris from the root halves and grooves.
A final flush was done using 5 mL of 17% EDTA for 1 min and 5 mL of 3% NaOCl for 1 min. The root canals were then dried with paper points. The teeth were randomly divided into three groups each containing 15 samples based on the intracanal medicament used.
Group I - Triple Antibiotic Paste (Penta Pharmaceuticals, Silvassa, India)
Group II - Odontopaste (ADM, Australia)
Group III - Metapex (Meta Biomedco Ltd, Korea)
Group 1: Triple antibiotic paste (n = 15)
The three antibiotics were kept separately in moisture-tight porcelain containers until use. Equal portions of metronidazole, ciproﬂoxacin, and minocycline (Penta Pharmaceuticals, Silvassa) were mixed with distilled water (a powder 0.5 gm/liquid 1 mL ratio of 3:1), using a clean spatula on a mixing pad. The grooves were ﬁlled with TAP, the root halves were reassembled by means of sticky wax. Access to the root canals was temporarily sealed with a cotton pellet and cavit, and then remounted in the Eppendorf vial.
Group II: Odontopaste (n = 15)
Odontopaste (ADM, Australia) was filled in the groove according to the manufacturer's instructions. The root halves were reassembled by means of sticky wax. Access to the root canals was temporarily sealed with a cotton pellet and cavit, and then remounted in the Eppendorf vial.
Group III: Metapex (n = 15)
Metapex (Meta Biomedco Ltd, Korea) was filled in the groove according to manufacturer's instructions. The root halves were reassembled by means of sticky wax. Access to the root canals was temporarily sealed with a cotton pellet and Cavit, and then remounted in the Eppendorf vial.
The specimens were kept at 37°C with 100% humidity for 1 week. Each specimen was then irrigated with 10 mL of 3% NaOCl for 1 min and agitated using a passive ultrasonic device. Then, the root canals were dried with paper points, and the roots were disassembled to evaluate the removal of the medicament. Digital images at 20 × magnification were then obtained using a stereomicroscope attached to a digital camera and then transferred to the computer.
| Results|| |
The amount of medicament remaining in the grooves was scored using the following scoring system:
0: The groove was empty.
1: Medicament was present in less than half of the groove.
2: Medicament covered more than half of the groove.
3: The groove was completely ﬁlled with medicament.
The values obtained were statistically analyzed using computer software Statistical Package for Social Sciences (SPSS) Version 22.0. The amounts of the remaining intracanal medicament score amongst different groups were analyzed with Kruskal–Wallis and Mann–Whitney tests. The level of significance was set at P < 0.05.
The results of this study are shown in [Table 1]. There was a statistically significant difference (P < 0.05) between the test groups in the remaining intracanal medicament score. Among the experimental groups, Odontopaste had the least remaining amount score, whereas Metapex had the highest remaining amount score.
|Table 1: Kruskal-Wallis comparison of the amount of the remaining intracanal medicament score in the canals for all groups|
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A graphic representation of the comparison of the remaining intracanal medicament score is shown in [Figure 1]. Stereomicroscopic images of medicaments remaining in the groove in the three groups are illustrated in [Figure 2], [Figure 3], and [Figure 4].
|Figure 1: Graphical representation of Mean amount of intracanal medicament remaining score in the canals for all groups|
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|Figure 2: Stereomicroscopic images of medicaments remaining in the groove – TAP|
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|Figure 3: Stereomicroscopic images of medicaments remaining in the groove – Odontopaste|
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|Figure 4: Stereomicroscopic images of medicaments remaining in the groove – Metapex|
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| Discussion|| |
Microorganisms play a fundamental role in the etiology of pulp and periapical diseases. Cleaning and shaping of the root canal reduce the bacterial population but do not completely eliminate them. One possible reason for persistent endodontic infection might be due to the retention of microorganisms in the dentinal tubules of the root canal after biomechanical preparation. Hence, the use of an intracanal medicament helps in the elimination of bacteria that remain even after cleaning and shaping, thereby providing an environment conducive for periapical tissue repair.
As the root canal infection is considered to be polymicrobial, three different types of intracanal medicaments i.e., an antibiotic-based intracanal medicament (TAP), Ca (OH)2– based intracanal medicament (Metapex), and a corticosteroid-based intracanal medicament (Odontopaste) were used in this study.
All interappointment dressings have to be removed from the root canal before obturation. Improper or partial debridement of the medicament leaves residues on root canal walls, thus affecting the bonding of endodontic sealers to canal walls or may result in increased apical leakage.,
Literature search shows that hand filing with saline or NaOCl irrigation does not remove the intracanal medicament completely from the canal. Hence, in this study, the passive ultrasonic irrigation technique was used for the removal of intracanal medicaments.
The experimental setup of this study is similar to that described by Lee et al. (2004). and has been used in several other investigations (van der Sluis et al. 2007, Jiang et al. 2010.). The advantage of the groove model is the standardized size and location of the grooves containing comparable amounts of medicament before irrigation. The scoring system used in this study has been described by van der Sluis et al. (2007).
In the present study, Odontopaste showed the least remaining amount score among all the test groups. Odontopaste is a zinc oxide–based root canal paste with 5% clindamycin hydrochloride, 1% triamcinolone acetonide, 0.25%–0.75% calcium hydroxide, and purified water. The enhanced removability of Odontopaste could be due to its water-soluble base, which can be rinsed out easily. Also, sodium hypochlorite, which was used as the final irrigant could have caused oxidization and degradation of its compounds.
The findings of the current study revealed that TAP had an intermediate remaining amount score, which was in between Metapex and Odontopaste. Minocycline in the TAP chelates calcium ions to form insoluble complexes that remain in calcifying tissues. Also, TAP appears to have high diffusion and retention within the dentin. Thus, the possible reason for the greater retention of TAP in the canal could be because of its penetration and binding into the dentin. This is in accordance with the study done by Berkhoff et al. (2014). They evaluated the effectiveness of the EndoActivator, passive ultrasonic irrigation, EndoVac, and syringe/Max-i-Probe needle irrigation techniques for the removal of TAP and Ca(OH)2. They concluded that none of the irrigation techniques effectively removed TAP from root canal systems, possibly because of its penetration and binding into the dentin, whereas calcium hydroxide is effectively removed with significantly less residual presence.
The present study showed that Metapex had the highest remaining amount score when compared to other test groups. Metapex is a silicone oil–based calcium hydroxide paste containing 38% iodoform. The presence of silicone oil resists dissolution in water, and hence this could be the reason for enhanced retention in the canal. This is in accordance with the study done by Suresh Nandini et al. They evaluated the efficacy of 17% EDTA and 10% citric acid in the removal of calcium hydroxide placed as an intracanal medicament using two different vehicles i.e., distilled water and silicone oil (Metapex). They concluded that oil-based calcium hydroxide is more difficult to remove than powder form calcium hydroxide mixed with distilled water. Thus, the vehicle used to prepare calcium hydroxide paste is important for its retrieval.
Limitations of the study
The major disadvantage of this in vitro model is that the standardized grooves do not represent the complexity of root canal anatomy.
| Conclusion|| |
Under the conditions of the study, it can be concluded that it was easier to remove Odontopaste from grooves within root canals with passive ultrasonic irrigation technique. On the other hand, TAP and Metapex showed greater retention within dentin and were not adequately removed. Among the test groups, Metapex showed the highest retention within the dentin. Although the residual medicaments within dentin have the potential to prolong their antibacterial effects, they also increase the likelihood of undesirable stem cell toxicity. Hence, further investigations have to be done on the effects of remaining medicaments in stem cell biology.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Dr. Mayuri Sailaja Pachalla
H. NO: 2-45/5/1; PLOT NO.46, SRI Raghavendra Nagar, Thattiannaram, Hyderabad – 500 068, Telangana
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4]