|Year : 2020 | Volume
| Issue : 2 | Page : 171-176
In vivo evaluation of zinc oxide-propolis mixture as root canal filling material in the primary molars: A 24-month follow-up randomized controlled trial
Kakarla Sri RojaRamya, C Vinay, KS Uloopi, Rayala Chandrasekhar
Department of Pedodontics and Preventive Dentistry, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India
|Date of Submission||11-Mar-2020|
|Date of Acceptance||11-Mar-2020|
|Date of Web Publication||28-Jun-2020|
Dr. Kakarla Sri RojaRamya
Department of Pedodontics and Preventive Dentistry, Vishnu Dental College, Bhimavaram . 534 202, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Pulpectomy is a routine practice in children with pulpal and periapical infections, the success of which depends on the elimination of bacteria from the root canals. Propolis, a natural product with proven antibacterial and anti-inflammatory properties when mixed with zinc oxide powder as root canal filling material, it could provide good success in endodontic therapy of primary teeth. Aim: The aim was to evaluate and compare the clinical effectiveness of zinc oxide-propolis mixture with zinc oxide eugenol (ZOE) as root canal filling material in nonvital primary molars. Settings and Design: This was a 2-arm, parallel group randomized controlled trial with blinded outcome assessment. Materials and Methods: Forty primary molars from children aged 4–8 years requiring pulpectomy treatment were randomly allocated into two groups according to the obturating material used: zinc oxide-propolis mixture (test group) and ZOE (control group). All the pulpectomy treated teeth were finally restored with stainless steel crowns, and the children were recalled at 6, 12, and 24 months for postoperative clinical and radiographic evaluation. Statistical Analysis: Chi-square test was used to analyze the data. Results: The overall success rate of pulpectomy with zinc oxide-propolis mixture and ZOE was found to be 95% and 70%, respectively, and the difference was statistically significant (P = 0.037). Zinc oxide-propolis mixture has shown a success rate of 100% at 6 months and 95% at 12 and 24 months follow-up, whereas ZOE has shown 80% success rate at 6 and 12 months, and it declined to 70% at 24-month follow-up. Conclusion: Zinc oxide-propolis mixture demonstrated good clinical and radiographic success at the end of 24 months, and hence, it can be considered as an alternate root canal filling material in the primary teeth.
Keywords: Propolis, pulpectomy, primary teeth, root canal filling material, zinc oxide, zinc oxide eugenol
|How to cite this article:|
RojaRamya KS, Vinay C, Uloopi K S, Chandrasekhar R. In vivo evaluation of zinc oxide-propolis mixture as root canal filling material in the primary molars: A 24-month follow-up randomized controlled trial. J Indian Soc Pedod Prev Dent 2020;38:171-6
|How to cite this URL:|
RojaRamya KS, Vinay C, Uloopi K S, Chandrasekhar R. In vivo evaluation of zinc oxide-propolis mixture as root canal filling material in the primary molars: A 24-month follow-up randomized controlled trial. J Indian Soc Pedod Prev Dent [serial online] 2020 [cited 2021 Jun 19];38:171-6. Available from: https://www.jisppd.com/text.asp?2020/38/2/171/288215
| Introduction|| |
Nonvital pulp therapy procedure is a routine practice in children to deal with pulpal and periapical infections, the success of which depends on the elimination of bacteria from the root canals. However, the complex root canal system of the primary teeth makes it difficult to achieve proper cleansing by mechanical instrumentation and irrigation of the canals. Hence, obturating material having good antibacterial properties is crucial and that will add to the better prognosis of the procedure.
Various root canal filling materials for the primary teeth have been tested from time to time; the routinely used and readily available materials are zinc oxide eugenol (ZOE), calcium hydroxide, and iodoform-based pastes. ZOE is the widely used obturating material. However, when eugenol in the ZOE mix leaches out to the periapical tissues, it causes irritation. ZOE also has limited antimicrobial action.
In order to overcome some of the disadvantages of currently available primary teeth root canal filling materials, there is a continued interest to search for better obturating material with broader and more effective antibacterial action. Propolis is a natural beehive product with potent antimicrobial and anti-inflammatory properties. The main chemical constituents present in propolis are flavonoids, phenolics, and other aromatic compounds. Considering the beneficial properties of propolis, a clinical trial was carried out to evaluate the effectiveness of zinc oxide-propolis mixture as root canal filling material in the primary molars.
| Materials and Methods|| |
The study design is a 2-arm, parallel group randomized controlled trial with 1:1 allocation and blinded outcome assessment. The study was approved by the institutional ethical board (VDC/IEC/2014-45) and is registered with the Clinical Trials Registry-India (CTRI/2018/04/013313). The experimental protocol is in compliance with the ethical standards of the human experimentation, Declaration of Helsinki. The study was conducted between July 2014 and July 2016. A total of forty nonvital primary molars indicated for pulpectomy in 4–8-year-old children attending the outpatient department of pediatric dentistry were included in the study, and the children were followed up for a period of 24 months after the therapy.
Nonvital primary molars with extraoral or intraoral swelling, sinus opening, Grade I mobility due to periradicular infection, and radiographic evidence of minimum bone degeneration were included in the study. The primary molars with less than two-thirds of the remaining root length, molars demonstrating extensive external or internal resorption, and teeth exhibiting greater than Grade I mobility and are nonrestorable with stainless steel crowns were excluded from the study.
Primary outcome is the success of zinc oxide-propolis mixture and zinc oxide eugenol as root canal filling materials in primary teeth at 6, 12 and 24 month follow-up periods.
The sample size was calculated setting the level of significance at 5% and power 80%. Based on the previous studies, to detect a difference of 25%, a sample size of 20 per group is required including 10% anticipated loss to follow-up.
Sequence generation and randomization
Randomization sequence was created using Excel 2007 with a 1:1 allocation using block randomisation of block sizes 2 and 4 by an independent doctor.
Allocation concealment mechanism and Implementation
The allocation sequence was concealed from the investigator using sequentially numbered, opaque, sealed and stapled envelopes. Generation of random allocation sequence, enrollment and assignment of participants to intervention were done by an independent doctor who is not involved in the clinical trial.
Participants, outcome assessor and data analyst were kept blinded to the allocation, whereas the operator could not be blinded because of the recognizable characteristics of the intervention materials
Interventions and Procedure
Prior written informed consent was obtained from all the parents/legal guardians of the participating children, and a total of forty teeth, comprising twenty in each group were randomly allocated to either test group (zinc oxide-propolis mixture) or control group (ZOE) by computer-generated randomization. In children allocated to test group, a patch test has been done with propolis, and if found allergic, they were excluded. Pulpectomy procedure was carried out under strict aseptic conditions. The teeth were isolated with rubber dam following local anaesthesia administration. After removal of all the carious debris, access to the pulp chamber was gained with #4 round bur, and the necrotic pulp tissue was extirpated using barbed broaches. Then, the working length was determined, and the root canals were enlarged up to the size 30–35 K files with intermittent irrigation using 1.5% sodium hypochlorite and normal saline.
If the tooth is asymptomatic, then the root canals were dried with sterile paper points and filled 1 mm short of the apex with zinc oxide-propolis mixture (Zinc oxide powder, Deepak enterprises, Mumbai, Maharashtra, India; Brazilian Green Propolis alcohol free 60%, Uniflora Health foods, Brazil) in test group and ZOE (Zinc oxide powder, Deepak enterprises, Mumbai, India; Eugenol, Prime Dental Products Pvt. Ltd., Thane, Maharashtra, India) in control group using lentulo spirals, and then, the access cavity was restored with glass ionomer cement. All the teeth were finally restored with stainless steel crowns, and the participants were instructed to report in case of any symptoms such as pain or swelling. The patients were recalled at 6, 12, and 24 months postoperatively. At each interval, teeth were evaluated clinically and radiographically to grade them as either success or failure.
The treatment outcome was considered successful clinically when there is absence of pain, no tenderness to percussion, absence or decrease in mobility and sinus opening, and radiographically when there are signs of resolution in the radiolucency, no new signs of postoperative radiolucency, and no signs of internal or external pathological root resorption demonstrated. All the follow-up evaluations were done by a blinded clinician. Group allocation, follow-up, and analysis are reflected in CONSORT flow diagram [Figure 1]. Radiographs of teeth treated with zinc oxide-propolis mixture and ZOE are illustrated in [Figure 2] and [Figure 3], respectively, which shows no pathological signs at any of the follow-up intervals.
|Figure 2: Radiographs of tooth 85 treated with zinc oxide-propolis mixture; (a) Immediate postoperative radiograph; (b) 6-month follow-up radiograph; (c) 12-month follow-up radiograph; (d) 24-month follow-up radiograph|
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|Figure 3: Radiographs of tooth 85 treated with zinc oxide eugenol; (a) Immediate postoperative radiograph; (b) 6-month follow-up radiograph; (c) 12-month follow-up radiograph; (d) 24-month follow-up radiograph|
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The collected data were entered into Microsoft Excel sheet and were subjected to descriptive statistical analysis using Chi-square test in IBM SPSS Statistics for windows, version 23 (IBM Corp., Armonk, New York, USA). For all the tests, P ≤ 0.05 was considered statistically significant.
| Results|| |
Participant flow through the trial is illustrated in [Figure 1]. A total of 40 children, 20 in each group were randomly assigned to zinc oxide-propolis mixture group and zinc oxide eugenol group. All the children received the interventions without any losses or exclusions. Participants were recruited in July 2014 and followed up till July 2016. The mean age of participants was 6 years (range: 4 -8 years) with similar numbers of boys and girls. There were no losses to follow-up at any of the evaluation periods. The overall success rate of pulpectomy with zinc oxide-propolis mixture and ZOE at the end of 24 months was found to be 95% (n = 19) and 70% (n = 14), respectively, and the difference was statistically significant (P = 0.037) [Table 1].
At 6-month follow-up, forty pulpectomy treated teeth were available for evaluation, and no failures were seen in zinc oxide-propolis group, whereas ZOE group has shown four failures. Zinc oxide-propolis and ZOE groups have yielded a success rate of 100% (n = 20) and 80% (n = 16), respectively, and the difference was statistically significant (P = 0.035) [Table 1].
At 12-month interval, the success rate of zinc oxide-propolis group reduced to 95% (n = 19) with one failure, whereas the success rate of ZOE remained the same with no more failures, and the difference was statistically not significant (P = 0.151) [Table 1].
Finally, at 24 months, no further failures were reported in zinc oxide-propolis group with the success rate remaining same as 12-month interval, whereas two more failures were reported in ZOE group, and the success rate reduced to 70% (n = 14) [Table 1].
| Discussion|| |
Endodontic therapy for infected primary dentition aims to preserve the child's health by maintaining the deciduous teeth in a functional state until they are replaced by permanent teeth. At present, the most commonly used root canal filling materials for the primary teeth are ZOE, calcium hydroxide, and iodoform-based pastes. Perhaps, none of the currently available materials meet all the ideal requirements. Concerns about the shortcomings of available materials have led to a search for alternate root canal filling materials for the primary teeth.
Propolis has gained the attention of researchers in recent times because of its beneficial properties. It has wide range of applications in the field of medicine and dentistry. In dentistry, propolis has been used for root canal irrigation, direct and indirect pulp capping, reduction of dentin hypersensitivity, caries prevention against Streptococcus mutans, and as a storage media for avulsed teeth.
In the present study, to confirm the presence of functional groups in zinc oxide-propolis mixture, Fourier transform infrared spectroscopy was performed. The spectrum of zinc oxide-propolis mixture showed the peaks at same wave numbers as that of propolis, and this confirmed the presence of functional groups [Figure 4]. Zinc oxide chelates with hydroxyl ions of the propolis, retaining all the beneficial chemical classes of propolis in the set mix. This, in turn, confirms that zinc oxide-propolis mixture retains all the beneficial properties of propolis.
|Figure 4: Fourier transform infrared spectra; (a) Fourier transform infrared spectrum of propolis; (b) Fourier transform infrared spectrum of zinc oxide-propolis mixture|
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ZOE has shown a success rate of 70% at the end of 24 months, and this was comparable to the success rates noticed by Holan and Fuks, and Mortazavi and Mesbahi., At the end of 6 months, ZOE has shown a radiographic failure in four teeth as an increase in furcational radiolucency. Two more failures were noticed at the end of 24 months in which one tooth has shown an increase in furcational radiolucency and the other tooth showed root resorption. These findings suggest that the antibacterial efficacy of ZOE is short lived.
Zinc oxide-propolis mixture has demonstrated a success rate of 95%, and a similar clinical success rate of 93.8% at 12-month follow-up was observed by Al-Ostwani et al. This success could be attributed to the antibacterial, antifungal, anti-inflammatory, and wound healing properties of propolis. Several studies have reported the significant antibacterial efficacy of propolis against Enterococcus faecalis, S. mutans, and Lactobacillus., Flavonoids (quercetin, galangin, and pinocembrin), caffeic acid, benzoic acid, and cinnamic acid in propolis probably act on the microbial cell wall, causing functional and structural damage.
Previous studies have reported the antifungal activity of propolis against Candida albicans., Flavonoids and phenolic acids in propolis damage the integrity of yeast cell wall. Propolis also has anti-inflammatory effect which suppresses the synthesis of prostaglandin, leukotriene, histamine, and transforming growth factor beta. This anti-inflammatory property of propolis could further enhance the healing of the periapical tissue and provides postoperative comfort. Arginine, Vitamin C, provitamin A, B complex, copper, iron, zinc, and bioflavonoids in propolis also assist in faster wound healing.
Zinc oxide-propolis mixture has shown a failure in one tooth in which root resorption was observed at the end of 12 months, and no more failures were observed at 24-month interval. The overall success rate with zinc oxide-propolis mixture was found to be superior compared to ZOE as root canal filling material. Although the success rate of zinc oxide-propolis mixture in this study was quite promising, clinical studies with long-term follow-up and large sample size are warranted to reach sound conclusions.
| Conclusion|| |
Zinc oxide-propolis mixture has demonstrated good clinical and radiographic success as root canal filling material in the primary molars at 24-month follow-up. This outcome was found to be superior compared to ZOE at all the time intervals. Hence, zinc oxide-propolis mixture can be considered as better alternative to conventional ZOE mix, wherein eugenol causes irritation to periapical tissues.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]