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| REVIEW ARTICLE |
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| Year : 2021 | Volume
: 11
| Issue : 1 | Page : 1-6 |
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Intracanal delivery of calcium hydroxide: A literature review
Vidhi Kiran Bhalla1, Sherin Jose Chockattu2
1 Department of Conservative Dentistry and Endodontics, ITS Centre for Dental Studies and Research, Ghaziabad, Uttar Pradesh, India
2 Department of Conservative and Endodontics, Bapuji Dental College and Hospital, Davangere, Karnataka, India
| Date of Submission | 18-Jan-2020 |
| Date of Decision | 14-Mar-2020 |
| Date of Acceptance | 22-Apr-2020 |
| Date of Web Publication | 09-Jan-2021 |
Correspondence Address:
Dr. Vidhi Kiran Bhalla
Department of Conservative Dentistry and Endodontics, ITS Centre for Dental Studies and Research, Ghaziabad, Uttar Pradesh
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/sej.sej_11_20
Introduction: Intracanal medication with calcium hydroxide is an important adjunct to disinfection after the chemomechanical preparation. A dense and homogeneous filling up to the working length positively influences the outcome of endodontic treatment in infected cases. The optimum placement of intracanal medicament can many times become a challenging task, owing to the lack of usage of the appropriate instruments and techniques.
Aim: The aim is to gather and assess available literature on the rationale of calcium hydroxide placement, instruments, and techniques for effective delivery.
Materials and Methodology: An electronic search was conducted using the PubMed Database from 1970 to 2019 using the keywords “delivery of calcium hydroxide,” “placement of calcium hydroxide,” “density of calcium hydroxide.” The articles pertaining to the comparison between the placement techniques of calcium hydroxide dressing were analyzed.
Results: The search identified 433 articles, from which 419 articles that did not fulfill the inclusion criteria were excluded from the study and eventually 13 research articles were analyzed for the review.
Conclusion: The density of calcium hydroxide and the technique of placement may affect the healing outcome especially in cases of pulp necrosis with apical periodontitis. The use of lentulo spirals at lower speeds seems effective in intracanal delivery of calcium hydroxide.
Keywords: Calcium hydroxide delivery, calcium hydroxide instruments lentulo spirals, intracanal medicament
How to cite this article:
Bhalla VK, Chockattu SJ. Intracanal delivery of calcium hydroxide: A literature review. Saudi Endod J 2021;11:1-6 |
| Introduction | |  |
The success in endodontic treatment depends on the identification and elimination of the etiologic factors involved in the development of apical periodontitis. Microorganisms are the primary etiologic agent in apical periodontitis and their elimination from the root canal system promotes healing of the periradicular tissues.[1] Mechanical instrumentation along with a thorough chemical debridement is essential for effective debridement of the root canal space and is ultimately related to the treatment outcome. The chemical (therapeutic) treatments involve the use of irrigants and intracanal medicaments delivered by various means into the intraradicular compartment.[2],[3],[4]
An effective intracanal dressing is a predictor of the outcome of endodontic treatment, especially in the presence of infected canals.[5] The use of inter appointment agent in a multi-visit approach results in maximum reduction in bacterial load prior to filling. Residual bacteria remaining in the apical part of the root canal system including the apical ramifications and lateral canals obtain their nutrition from the periradicular tissues and this helps to sustain long-standing infections.[6]
Calcium hydroxide, introduced by Hermann in the year 1920 has been considered a gold standard intracanal medicament in endodontics.[7] The alkaline pH of 12.5 alters the integrity of cytoplasmic membrane by either causing cellular injury to various organic components or by means of destruction of the phospholipid or fatty acid content on the membrane.[8] Even though its anti-bacterial efficiency may be less than desirable, it remains the only medicament proven till date, to have tissue dissolution capability and anti-lipopolysaccharide activity. The antibacterial activity is attributed to the release of hydroxyl ions, which must diffuse through the dentin as well as resist its buffering action, so as to effectively reach the inaccessible and deeper areas. To achieve this, it is essential to deliver the medicament homogeneously within the root canal system.[9],[10] Studies have concluded that complete filling of the canal to within 1 mm of the radiographic apex with calcium hydroxide produced the greatest pH change on the external surface of the root, than filling it 3 or 5 mm short of the apex.[11]
Several methods have been advocated in the literature for delivery of calcium hydroxide pastes such as hand files, lentulo spirals, and other devices such as syringes and compactors.[12] However, the search for an ideal placement technique continues. The present review attempts to gather and assess available literature on the rationale of calcium hydroxide placement, instruments, and techniques for effective delivery for improved endodontic treatment outcome.
| Materials and Methodology | | |
A literature search was conducted on PubMed database for articles with the following MeSH words and keywords applied with the Boolean operator: (“delivery of calcium hydroxide” [Mesh] OR “placement of calcium hydroxide” [Mesh] OR “calcium hydroxide density” [Mesh]). The inclusion criteria included all relevant peer reviewed articles pertaining to the placement method for calcium hydroxide dressing from the year 1970–2019 and were limited to the English language publications. Full text articles were acquired electronically and cross references were further screened to identify relevant articles. The search was confined to the articles comparing and evaluating the efficacy of various modes of delivery of calcium hydroxide dressing within the root canal space. Furthermore, studies in only abstract form, review articles, case reports, and letters to the editor were excluded from analysis.
| Results | | |
The search yielded 433 articles in the initial phase. However, 419 articles were excluded because they were unrelated to the subject or were in only abstract form. A total of 13 original research in vitro articles were included in the analysis and reviewed.
| Discussion | | |
Rationale for calcium hydroxide placement
Authors have disputed the validity of using intracanal medications, or have limited its usage to select clinical situations such as “weeping canals,” “traumatic injuries,” or “large periapical lesions.” Others have supported its application in disinfection of infected canals and management of internal resorption. A high success rate of over 94% after endodontic treatment with intracanal dressing has been reported.[12] Nonsurgical healing of a radicular cyst has been reported following extraradicular placement of calcium hydroxide.[13] Fact remains that, as long as, the controversy on single versus multi-visit endodontic treatment rages on, intracanal medicaments remain relevant and more so in the treatment of pulpal necrosis and apical periodontitis.[14],[15]
According to Rehman et al. calcium hydroxide, on contact with aqueous fluids undergoes ionic dissolution into calcium and hydroxyl ions. The release of highly reactive hydroxyl ions contributes to the antibacterial activity by affecting the cytoplasmic membranes, proteins and DNA.[16] For effective action, the hydroxyl ions must be present in sufficient numbers so as to resist the buffering action of the dentin as well as diffuse through the dentin to reach the deeper and inaccessible areas. Studies have shown that the hydroxyl ions diffused faster cervically rather than apically and the diffusion was limited to a minor distance within the canal.[17],[18] Hence, the effective delivery of the medicament till the apical third becomes crucial for effective antimicrobial action in the clinical situations such as weeping canals, pulpal necrosis, and periapical lesions.
Methods of placement of calcium hydroxide
Instruments
Calcium hydroxide has a thixotropic behavior, i.e., the material becomes fluid when agitated. Thus, calcium hydroxide can be mixed to a very thick consistency yet it will flow when agitated. The placement of large amounts of calcium hydroxide slurry is desirable to achieve sufficient pH rise and antibacterial conditions.[19],[20] The method of calcium hydroxide placement affects the pH of the dentin inside the root canal as well as the surrounding dentin. In other words, the antibacterial activity is determined by the diffusion of hydroxyl ions throughout the root canal system which requires its effective delivery.[21]
Calcium hydroxide may be delivered in the root canal system through a variety of methods. The methods may be broadly classified as hand instruments, rotary instruments, and sonic and ultrasonic devices [Figure 1]. The hand instruments includes K–files, Flex-O-files, pluggers, spreaders, paste carriers, amalgam carriers, and paper points; the rotary instruments includes paste carriers (lentulo spirals), PasteInject (Micro Mega), rotary nickel titanium (Ni-Ti) files and McSpadden Compactor; the sonic and ultrasonic devices includes ultrasonic files (Micro Mega®) and sonic activation through Endo-Activator (Dentsply) devices.[22],[23]
Technique of placement: Literature evidence
In endodontic literature, several placement techniques have been evaluated and their efficiency has been compared to other methods.
The use of specially designed paste carrier has been evaluated in a study by Tan et al.,[24] and the technique has been found to be effective when assessed radiographically. This technique utilized four stainless steel Luer lock needles of varying diameters (16, 18, 21, and 24G). The thinner needles, after sectioning the bevel and filling with cyanoacrylate, were inserted into the thicker needle (16G) and the length was adjusted using rubber stoppers. The presence of a large diameter needle acted as a barrel and enabled optimal delivery of the dense consistency of the mix. Furthermore, the use of multiple needles with increasing diameters ensured optimum condensation forces. However, the technique presents a limitation in severely curved canal due to the rigidity of stainless steel. In addition, the use of special syringes and needles increases the possibility of paste extrusion into the periradicular tissues, probably because of the hydraulic pressure created by the injectable dispensing forms.[24]
An optimally thick paste can be best applied with a latch-type paste carrier (lentulo spiral) of appropriate size. The filling action is due to the spiral's action on the canal walls. For maximum effect, the lentulo spiral should be as large as possible relative to the size of the root canal without binding to the canal walls and should be placed 2 mm short of the working length (WL) for medicament insertion.[21] Studies have reported that lentulo spirals produced homogenous fillings. A study by Teixeira et al. (2005) concluded that the placement of calcium hydroxide paste with a lentulo spiral and the subsequent compaction with the blunt-end of paper point obtained a higher pH values than using paper points alone.[25]
Another study by Peters et al., concluded that calcium hydroxide placed in canals prepared to apical size 40 and taper 4% had the least number of voids when compacted using lentulo spiral than injection technique.[26]
The use of paste inject and lentulo spirals have been found to be suitable in mature teeth that have been instrumented to smaller diameters (<0.4 mm diameter) as well as for curved canals. The flattened blade of Paste inject may amplify the “Archimedean Screw effect” and enhance the placement homogeneously within the root canals.[27] In another study by Torres et al., use of an Ultradent tip was investigated in stimulated curved canals and was compared with lentulo spirals alone and in conjunction with Ultradent tip. Ultradent has a 0.014 inch diameter tip, composed of polypropylene plastic for ease of calcium hydroxide placement. The study concluded that the calcium hydroxide density was significantly greater using a lentulo spiral only technique.[28]
Another study by Simcock and Hicks assessed the weight with the radiographic appearance of calcium hydroxide delivered into prepared canals using an injection system, endodontic Flex-O file rotated counterclockwise, lentulo spiral, 04 rotary NiTi file rotated in reverse. Regardless of technique used, only about 45% of the optimal weight of calcium hydroxide was delivered into the minimally prepared canal.[22]
Kleier et al. recommended the use of Mc Spadden compactor.[29] However, the results were contradictory in studies by Estrela et al.[30] and Deveaux et al.[27] The Mc Spadden compactor has a larger straight section than the lentulo drill and causes displacement of the paste laterally, increasing the percentage of empty spaces.[30]
In a recent study by Galvão et al. the effectiveness of sonic devices (Endo Activator) was assessed in filling the root canal system. The results of the study contraindicated the use for this purpose. The use of sonic activation was not effective and seemed to dislodge and disperse the medication rather than making it more dense.[23]
Another study by Sharifi et al. (2019) compared the effectiveness of a hand file, rotary file, and lentulo spirals in stimulated curved canals and concluded that a rotary file operating in counterclockwise direction was the most effective in delivering the medicament till the apical thirds in curved canals. This was possibly attributed to the high flexibility of Ni-Ti files which allowed more effective and dense delivery in curved canals.[30]
Width and curvature of the root canal influences complete or incomplete filling of the root canal system. Wider and straighter canals are more easily filled than the curved canals.[26],[31] The study by Dumsha and Gutmann has concluded that the clinician should evaluate the clinical situation before choosing the most appropriate method for the placement of calcium hydroxide. An adequate canal preparation enhances a more homogeneous and dense placement.[21] A summary of the various studies is provided in [Table 1] and [Table 2]. | Table 1: Summary of the various studies on intracanal delivery of calcium hydroxide
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 | Table 2: Summary of the various studies on intracanal delivery of calcium hydroxide
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Methods for assessing placement
Calcium hydroxide mixed with any of the vehicles (aqueous, viscous, or oily) lacks radioopacity and hence cannot be visualized radiographically. To allow radiographic visualization, radiopacifiers such as barium sulfate, barium, and other compounds containing iodine and bromine have been added.[32] In most of the in vitro studies, radiographic assessment of the fill has been done after the addition of radioopacifier. However, radiographs are unreliable as they provide a two-dimensional view.[20]
Influence of placement technique on healing outcome
Success rate of over 80% have been reported with the use of calcium hydroxide when used for successful management of teeth with periapical lesions.[33] Many investigators have reported that direct contact between calcium hydroxide and the periapical tissues is beneficial for the inductive action of the material.[34] However, there have been case reports of healing of periapical lesions after the placement of calcium hydroxide beyond the apex. Moreover, the density of the fill has not been correlated with the healing outcome in any study.
Clinical guidelines/recommendations
Calcium hydroxide continues to be the first choice of medication for endodontic treatment especially for cases of resorption, large periapical lesions, and weeping canals. To attain its maximum benefits, it is highly important to deliver it adequately within the root canal system.[35]
Based on the review, following are the clinical guidelines and recommendations for effective intracanal delivery of calcium hydroxide:
- For effective medicament delivery, an optimal canal preparation is a prerequisite. A minimum apical preparation till 25 K-file size in curved canals and 40 K-file size in straight canals must be achieved before medicament placement[26]
- The use of rigid stainless steel files has limited efficacy in curved canals[31]
- The use of lentulo spirals, at lower speeds (5000 rpm) placed 2 mm short of the WL, aided by compaction with the blunt-end of paper points may be effective in promoting better antimicrobial efficacy[22]
- Master apical file with the rubber stopper adjusted to the WL is recommended for hand placement, whereas when using rotary instruments, the rubber stopper should be adjusted 2 mm short of the WL since rotary instruments tend to displace and dislodge the filling material beyond the apex[21]
- The use of sonic devices has been found to be ineffective due to the dispersion force created by the vibrations.[23] However, more studies are warranted.
| Conclusion | | |
Owing to the favorable properties of calcium hydroxide in the treatment of pulpal necrosis and apical periodontitis, the effective delivery of intracanal medicament remains valid and relevant. The use of lentulo spirals at lower speeds seems effective in intracanal delivery of calcium hydroxide. The density of the calcium hydroxide medicament after chemo mechanical preparation may affect the endodontic outcome in infected teeth. However, there are no studies, till date to support this evidence and further studies are warranted in this aspect.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1]
[Table 1], [Table 2]
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