|Year : 2017 | Volume
| Issue : 4 | Page : 90-96
Outcome of zinc oxide eugenol paste as an obturating material in primary teeth pulpectomy: A systematic review
Harsha S Nalawade, Gauri S Lele, Hrishikesh Walimbe
Department of Pedodontics and Preventive Dentistry, Dr. D.Y. Patil Vidyapeeth, Dr. D.Y. Patil Dental College and Hospital, Pune, Maharashtra, India
|Date of Web Publication||15-Feb-2018|
Harsha S Nalawade
Department of Pedodontics and Preventive Dentistry, Dr. D.Y. Patil Vidyapeeth, Dr. D.Y. Patil Dental College and Hospital, Pune - 411 018, Maharashtra
Source of Support: None, Conflict of Interest: None
The aim of this systematic review is to use the principles of evidence-based dentistry to evaluate the outcome of zinc oxide eugenol (ZOE) paste as an obturating material in primary teeth pulpectomies. Moderate-to-high success rates are reported with ZOE in preserving chronically infected primary teeth. However, it fails to meet many of the criteria for an ideal obturating material. Databases searched were PubMed, EBSCOhost, and Google Scholar. Articles published between January 1, 1993, and June 30, 2016, with in vivo studies for obturating materials in primary teeth pulpectomy with placement of preformed crown, reporting follow-up period of at least 12 months with clinical and radiographic success rates were selected for this review. In total, 122 articles were retrieved. After the removal of duplicates and screening, full-text articles were analyzed; of which eight articles were selected for the systematic review. No significant difference was seen in the outcome of obturating materials used in comparison with ZOE in the included studies. Outcomes of ZOE paste obtained with clinical and radiographic evaluation were similar when compared to the newer combinations of materials available for obturating primary teeth today. More number of randomized controlled clinical trials for primary teeth pulpectomies with at least 12 months follow-up period and placement of crown as final restoration need to be carried out for testing the newer materials in comparison with ZOE to conclude a suitable alternative obturating material.
Keywords: Clinical evaluation, obturating material, primary teeth pulpectomy, radiographic evaluation, systematic review, zinc oxide eugenol
|How to cite this article:|
Nalawade HS, Lele GS, Walimbe H. Outcome of zinc oxide eugenol paste as an obturating material in primary teeth pulpectomy: A systematic review. J Dent Res Rev 2017;4:90-6
|How to cite this URL:|
Nalawade HS, Lele GS, Walimbe H. Outcome of zinc oxide eugenol paste as an obturating material in primary teeth pulpectomy: A systematic review. J Dent Res Rev [serial online] 2017 [cited 2018 Mar 22];4:90-6. Available from: http://www.jdrr.org/text.asp?2017/4/4/90/225634
| Introduction|| |
The primary objective of pulp therapy is to maintain the integrity and health of the teeth and their supporting tissues. In case of primary teeth that demonstrate chronic inflammation or necrosis beyond the coronal pulp, pulpectomy is the preferred treatment.
The aim of pulpectomy is to retain teeth with irreversible pulp pathosis in a symptom-free state until their exfoliation. Root canal therapy for primary teeth was advocated as early as 1932 as a method for retaining those primary teeth which would otherwise be lost.
Thus, these teeth act as natural space maintainers, restoring the normal masticatory function and esthetics. Pulpectomy also helps in preserving the arch length, preventing aberrant tongue habits, and speech alterations.
However, due to the complex anatomy of their root canals, endodontic treatment of infected primary molars is a great challenge, and chemo-mechanical therapy is insufficient to disinfect all the bacteria from root canals., The rationale of pulpectomy includes the removal of irreversibly inflamed or necrotic pulp tissue by cleaning the root canal system, followed by filling of the root canal with a material that resorbs at the same rate or faster than the primary root and can be eliminated rapidly if accidentally extruded through the apex., Of the various root canal filling materials for primary teeth, zinc oxide and eugenol (ZOE) paste was the first root canal filling material to be recommended for primary teeth, as described by Sweet in 1930.
An ideal root canal filling material for primary teeth should have several properties, such as resorbing at a rate similar to that of the primary root, being harmless to the periapical tissues and permanent tooth germ, resorbing readily if pressed beyond the apex, and being strongly antiseptic., It should easily fill the root canals, adhere to the walls of the canal, not be susceptible to shrinkage, be easily removed if necessary, be radiopaque and not discolor the tooth., It also should not set to a hard mass which could deflect an erupting succedaneous tooth.,
Successful obturation requires the use of materials and techniques capable of densely filling the entire root canal system and providing a fluid tight seal to prevent reinfection. This also implies that an adequate coronal filling or restoration be placed to prevent oral bacterial microleakage. It has been shown that endodontic treatment is dependent both on the quality of the obturation and the final restoration.
Several authors have reported moderate-to-high success rates in preserving chronically infected primary teeth using ZOE for obturation.
However, according to several studies,, ZOE fails to meet many of the criteria for an ideal obturating material. The use of an iodoform base or Ca (OH)2-containing materials as substitutes for ZOE has received attention in recent years. In contrast to ZOE, these modern combinations of material as medicaments are more easily resorbed from the periapical area and cause less reported foreign body reaction.
Thus, this systematic review may aid clinicians and researchers to explore the various options available for materials that can be used for obturation in primary teeth pulpectomies. The clinical research question being how effective is zinc oxide eugenol (ZOE) paste as an obturating material in primary teeth pulpectomies with crown as final restorations, in its clinical as well as radiographical outcomes after a 12 or more months of follow-up by clinical trials and retrospective study designs.
The objective of this systematic review is to use the principles of evidence-based dentistry to evaluate the outcome of ZOE paste as an obturating material in primary teeth pulpectomies.
| Methods|| |
The dental literature on obturating materials for primary teeth pulpectomies was reviewed. The databases used for the search were PubMed, EBSCOhost, and Google Scholar from January 1, 1993, to June 30, 2016. Combinations of the keywords used to develop search strategies applied for the PubMed database are given in [Table 1].
|Table 1: Keywords used to develop search strategies for the PubMed database|
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In addition to the electronic database searching, manual search in journals of Pediatric Dentistry related to the topic of interest was performed in the institutional library. Dissertations on similar topics were screened for their references at the institution. All cross-reference lists of the selected studies were also screened for additional papers that could meet the eligibility criteria of the study. Contact to authors and colleagues working on similar subjects in the field was made through E-mails.
- Articles in English or those having detailed summary in English
- Studies published between January 1, 1993, and June 30, 2016
- In vivo studies that provide information for obturating materials in primary teeth pulpectomy
- Randomized controlled trials and original research stating the outcome of ZOE alone as an obturating material in primary teeth
- Randomized controlled trials and original research stating the outcome of ZOE with other materials as an obturating material in primary teeth
- Studies reporting follow-up period of 12 months or more
- Studies reporting clinical and radiographic success rates
- Studies reporting completed procedure for pulpectomy until the placement of preformed crown.
- Reviews, case reports, abstracts, letters to editors, editorials, and in vitro studies
- ZOE used as interim restoration
- Studies with only clinical/radiographic success rate
- Studies for permanent teeth
- Animal studies.
P – Participant: primary teeth undergoing pulpectomy
I – Intervention: ZOE paste used as an obturating material for pulpectomy followed by the placement of preformed crown as final restoration
O – Outcome measure: assessed by both clinical and radiographic success rate at the end of follow-up period of 12 months or more
S – Study design: clinical trials and original research
Selection of studies was done initially by reading the title and abstract of the articles obtained from each database. Only those articles that were relevant to the review were collected and put for further evaluation. Articles reporting information based on pulpotomy, endodontic treatment for permanent teeth, and animal studies were excluded. Furthermore, studies reporting ZOE used as interim restoration, those with <1 year of follow-up period for pulpectomy and without the placement of crown as final restoration were also excluded [Table 2].
|Table 2: Reasons for exclusion of the full-text articles analyzed for eligibility are as stated below|
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Clinical trials and retrospective studies fulfilling the inclusion criteria were assessed further for the review. Full-text articles of the selected abstracts were then evaluated independently. The selection process involved two independent investigators and a consensus decision was made with a third evaluator to shortlist the articles that met all the inclusion criteria for the systematic review [Figure 1]. Reference lists of the selected articles were also searched for additional data that might have been missed. There were no restrictions placed on the maximum follow-up period or sample size for the studies selected.
The data were collected and analyzed from each article on discussion by the same investigators that selected them and a standard pilot data extraction sheet was prepared in consult with the evaluator as an expert [Table 3].
|Table 3: Characteristics of the studies included in this systematic review|
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| Results|| |
The data search was carried out by initially identifying 121 articles from the electronic database based on the title relevant to the systematic review. Majority of the articles were retrieved from the PubMed database. One article was retrieved by contacting the author.
After removal of duplicates, 38 articles remained which were screened through abstracts. Of these, 16 full-text articles were analyzed for eligibility, out of which 8 were selected for qualitative synthesis of the systematic review. This comprised 6.55% of the total articles obtained pertaining to the data search (8 out of 122).
| Discussion|| |
The aim of pulp therapy for primary teeth is mainly to restore the form and function of the tooth, and in turn, the oral and general health of the child. The lack of treatment of a deciduous tooth with irreversible pulpitis or pulpal necrosis can cause damage to the succedaneous tooth and produce a negative impact on the child's oral health-related quality of life.
The outcome of an endodontically treated primary tooth is affected not only by the irrigating solutions and biomechanical preparation but also by the obturating material.
Conventionally, ZOE has been the material of choice for filling the root canals of deciduous teeth. Up to 2008, it was the only material recommended in the clinical guidelines for pulp therapy in primary teeth by the AAPD.
Although plenty of research has been done on endodontic therapy of primary teeth, not many articles are available to compare the outcome of the different obturating materials used to provide evidence in deciding on an ideal material of choice.
The evaluation of the selected articles of this systematic review has been done by similar clinical and radiographic criteria and a regular follow-up period to assess the outcome of the obturating material. Inclusion criteria in the selected articles differed in their sample selection; however, ZOE as obturating material remained as a constant element in all of them.
Barr et al., in 1991, stated that after primary teeth with ZOE pulpectomies were lost, they did not find retained filler particles associated with molar teeth. They reported that incisor pulpectomies may have retained ZOE initially after exfoliation, but it was not seen on subsequent radiographs at follow-up.
Sadrian and Coll, in 1993, stated that the data findings from their retrospective evaluation indicated that retained ZOE tended to resorb with time which may reflect osteoclastic activity to reduce or eliminate retained ZOE particles. The filling material took a mean time of 50.1 months for ZOE to resorb. In the cases in which ZOE was retained, 80% showed significant reduction of the retained filler's size over time. Thus, they advised that it is better to fill canals short of the apex rather than to the apex or beyond, to avoid retention. None of the retained filler particles caused any observed pathology. They concluded that retained ZOE was not related to the pulpectomy success or failure.
A more recent retrospective evaluation by Bahrololoomi and Zamaninejad  in 2015 for a success rate of ZOE as an obturating material for a mean follow-up period of 24 months also reports that two-visit pulpectomy of primary molars using ZOE for root filling is one of the most reliable and successful treatments for necrotic primary teeth.
In another retrospective evaluation by Holan and Fuks  in 1993 comparing pulpectomies of nonvital primary molars using ZOE and KRI paste, it was concluded that KRI paste presented with a higher success than ZOE in cases of first molars, maxillary molars and overfilling of the canals. Success rates for both materials were similar in underfilled teeth and slightly higher for KRI paste when fillings were flush to the apex.
In relation to primary anterior teeth, one of the included articles by Primosch et al. who assessed retrospectively ZOE pulpectomies in vital maxillary primary incisors concluded that the prognosis for these teeth was significantly reduced when treated as a result of trauma or when overfilled beyond the root apex.
Outcome of the relatively newer material combinations like calcium hydroxide/iodoform paste for obturation of primary teeth against ZOE was assessed to conclude that Vitapex appeared to resolve furcation and periapical pathology at a faster rate than ZOE at 6 months; however, a similar success rate of 89% versus 85% was observed at 12-month follow-up. Nurko and Garcia-Godoy  reported that resorption of extruded Vitapex took 1–2 weeks up to 2–3 months. However, Trairatvorakul and Chunlasikaiwan  observed it to be as late as 6–12 months in 30% of the sample in their study. This was similar to findings reported by Ozalp et al.
Similarly, a comparative clinical study by Subramaniam and Gilhotra  to evaluate Endoflas, ZOE, and Metapex as obturating materials for primary molars was carried out, and no significant difference between the three materials was observed at the end of 18 months. However, a higher number of overfilled canals and the presence of voids were observed with Metapex. This could be due to the thinner consistency of the premixed paste which may flow more easily into the narrow and tortuous canals of primary molar teeth and reach the apex or even beyond  or also due to the technique followed, wherein the filling material is pressed into the canal. Unlike ZOE, Metapex can be rapidly eliminated when extruded extra-radicularly and does not set to a hard mass. However, there is a possibility of intra-radicular resorption in the long term.
Al-Ostwani et al., in 2016, conducted a study to compare the clinical and radiographic outcome of four different root canal filling materials in primary molars, namely, zinc oxide with propolis (ZOP) as a new paste, endoflas-chlorophenol-free, metapex, and ZOE as control paste. They reported similar results as Subramaniam and Gilhotra  and Trairatvorakul and Chunlasikaiwan, who explained the slower resorption of ZOE than the root as its particles are resistant to the giant cells, and hence, high concentrations of eugenol released from the remaining ZOE may affect the surrounding tissue and delay the healing process. However, they concluded that ZOE paste had convergent efficacy to the other pastes in comparison and also that the combination of ZOP is a promising material with its natural antibacterial action.
Pramila et al., in 2016, compared the outcome of three root canal filling materials in primary molar pulpectomies using ZOE with iodoform (RC Fill), Vitapex, and ZOE. In contrast to the other two groups, Vitapex was associated with both intraradicular resorption and resorption of the extruded filling material at the follow-up visits. The intraradicular resorption with Vitapex could be attributed to the fact that calcium hydroxide does not set to a hard mass and is hydrosoluble, hence permeable to tissue fluids and dissociable into ions. Severe preexisting pathosis could have contributed to the worsening of the radiolucencies and external root resorption that were observed in a few teeth which eventually resulted in failure. All three materials were found to be equally effective for obturating primary molars with necrotic pulps and irreversible pulpitis at the end of 30-month follow-up period.
Even though the AAPD guideline  on pulp therapy states that the radiograph showing infectious process of pulpectomized teeth should resolve in 6 months, the selected studies' results agreed with previous studies , that, in some cases, more definitive assessments could be made at longer follow-up times. Hence, this review included only those articles with a follow-up period of 12 months or more.
This indicated improvement in the treated teeth and varied results for the outcome of materials was observed, as every material yielded different tissue response from the surrounding tissues of the treated tooth at a different pace.
According to Moskovitz et al., the rate of success did not significantly relate to the extent of root canal filling nor the presence of a preexisting radiolucent area. They emphasized that the success depended on prevention of micro-leakage and placement of a permanent restoration as soon as possible after the completion of root canal treatment. In this systematic review too, placement of preformed crowns was a mandatory inclusion criteria as they provide complete coverage and protect the tooth against leakage at the pulpal space-restoration interface, hence ultimately affecting the outcome of the treated tooth.
Complete matching of the samples was not possible at the start of the included studies due to the differing pathological state of the primary teeth and also patient response toward the obturating material. Complete blinding of the observer was not possible in the comparative studies for radiographic evaluation due to the faster rate of resorption of iodoformized pastes leading to bias results.
Short periods of evaluation should not be indicated to compare filling materials, and the exclusion of short-term follow-ups thus occurred in this systematic review. Furthermore, early evaluations indicated a positive outcome for all material groups with no significant difference that changed at the later follow-up.
No significant difference was seen in the outcome of obturating materials used in comparison with ZOE in the included studies. Studies with follow-up of more than 30 months were all retrospective in nature indicating the possibility of biased interpretation of data. Thus, more number of clinical trials regarding this subject are necessary.
Furthermore, data searched for this systematic review were limited to fewer number of electronic databases and articles published in English language only.
| Conclusion|| |
Based on the moderate level of evidence available to assess the outcome of ZOE as an obturating material by clinical and radiographical evaluation for primary teeth pulpectomies, it is fair to conclude that similar results were obtained when it was compared to the newer combinations of materials available today. There was no agreement on the resorption or effects on the developing tooth buds of the successors by these obturating materials. ZOE still remains as a suitable obturating material for primary teeth pulpectomies due to its advantages such as the ease of manipulation and handling, various techniques available today for placement into the canal, antimicrobial properties, availability, and cost effectiveness. This was in agreement with the two systematic reviews published earlier on this topic., However, the current review was carried out using more stringent inclusion criteria to evaluate the outcome and also aided in reviewing the latest literature available. More number of randomized controlled clinical trials for primary teeth pulpectomies with at least 12-month follow-up period and placement of crown as final restoration need to be carried out for testing the newer materials in comparison with ZOE to conclude a suitable alternative obturating material.
The authors acknowledge the guidance of Dr. Pradnya Kakodkar (Professor, Department of Public Health Dentistry, Dr. D.Y. Patil Dental College and Hospital, Pune) during this review.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]