|Year : 2019 | Volume
| Issue : 4 | Page : 392-398
Evaluation of a mixture of zinc oxide–10% sodium fluoride as novel root canal filling material: A pilot study!!
Himani Goel, Shivani Mathur, Vinod Sachdev
Department of Pedodontics and Preventive Dentistry, ITS Dental College, Ghaziabad, Uttar Pradesh, India
|Date of Web Publication||7-Nov-2019|
Dr. Himani Goel
Department of Pedodontics and Preventive Dentistry, ITS Dental College, Delhi-Meerut Road, Muradnagar, Ghaziabad - 201 206, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: To establish mixture of zinc oxide and 10% sodium fluoride as a novel root canal obturating material for primary teeth. Aim: This study aims to evaluate clinical and radiographic success of a mixture of zinc oxide and 10% sodium fluoride as root canal obturating material. Settings and Design: This pilot study was conducted among 30 primary molars indicated for pulpectomy. Methods: Thirty grossly decayed primary molars of children aged 4–9 years were selected with signs or symptoms of irreversibly inflamed or degenerative pulp tissue. Single sitting pulpectomy was carried out in all the teeth with a mixture of zinc oxide powder with 10% sodium fluoride, and they were subsequently restored with preformed crown. Teeth were assessed clinically and radiographically at 3-, 6-, 9-, and 12-month intervals. Statistical Analysis: Data were analyzed using SPSS Software Version 20.0 (IBM SPSS Statistics, Chicago, IL, USA) and statistical significance was determined by Chi-square test; level of significance was set at P < 0.05. Results: Overall clinical and radiographic success rate of combination of zinc oxide and sodium fluoride was 92.9% and 85.7%, respectively, at the end of 12 months. Furthermore, resorption rate of material matched resorption of tooth root. Excess filling material was also observed to resorb at the end of 3 months. Conclusion: These results suggest that combination of zinc oxide and sodium fluoride can be considered as suitable alternative root canal obturating materials for primary teeth with low cost to achieve acceptable therapeutic results.
Keywords: Obturating material, primary molars, pulpectomy, sodium fluoride, zinc oxide
|How to cite this article:|
Goel H, Mathur S, Sachdev V. Evaluation of a mixture of zinc oxide–10% sodium fluoride as novel root canal filling material: A pilot study!!. J Indian Soc Pedod Prev Dent 2019;37:392-8
|How to cite this URL:|
Goel H, Mathur S, Sachdev V. Evaluation of a mixture of zinc oxide–10% sodium fluoride as novel root canal filling material: A pilot study!!. J Indian Soc Pedod Prev Dent [serial online] 2019 [cited 2019 Nov 17];37:392-8. Available from: http://www.jisppd.com/text.asp?2019/37/4/392/270472
| Introduction|| |
Guidelines of the American Academy of Pediatric Dentistry state that in deciduous teeth with irreversible pulpitis or necrosis or a tooth treatment planned for pulpotomy in which the radicular pulp exhibits clinical signs of irreversible pulpitis (e.g., excessive hemorrhage that is not controlled with a damp cotton pellet applied for several minutes) or pulp necrosis (e.g., suppuration and purulence), pulpectomy is indicated.,
Root canal preparation in a deciduous tooth is based mainly on chemical means rather than mechanical debridement due to several reasons specifically related to instrumentation including root canal morphology, great number of collateral canals, process of physiological root resorption, and the possibility of damage to the permanent successor.,, To overpower these instrumentation hurdles, various materials have been tried over the years to match the resorption rate with that of the physiologic root resorption of the deciduous teeth leading to success of root canal treatment.
The commonly used materials for deciduous root canal fillings are zinc oxide eugenol (ZnOE), iodoform-based pastes and calcium hydroxide or various combinations of these materials. ZnOE is still considered as the gold standard; however, it has certain disadvantages such as slow resorption, irritation to periapical tissues, and necrosis of bone and cementum and alters the path of succedaneous tooth. Calcium hydroxide introduced in 1920 has the disadvantage of resorbing earlier than the physiologic resorption of root of deciduous teeth. This creates a “hollow tube” effect wherein an unfilled root canal is permeated with tissue fluid that eventually becomes a site of infection., Iodoform-based materials for root canal therapy have better resorbability, if pushed beyond the apex and disinfectant properties,,, but it is irritating to periapical tissue and can cause cemental necrosis., Iodoform in combination with calcium hydroxide, namely vitapex and metapex has been shown to resorb earlier than the physiologic resorption of tooth root. Endoflas is another such material, which is the combination of ZnOE, calcium hydroxide, and iodoform. However, eugenol which is one of its constituents may lead to periapical irritation.
Various studies have been carried out in quest to search for an effective filling material to overcome the disadvantages of different combinations of ZnOE, iodoform, and Ca(OH)2. In 2001, mixture of ZnOE and calcium hydroxide was used as a root canal filling material in deciduous molars by Chawla et al.; however, this mixture was also found to resorb at a faster rate than the physiologic resorption of the roots of the deciduous teeth., Thereafter, a need of adding a material which match the resorption rate of roots of deciduous teeth was felt. Subsequently, fluoride was added as it was thought that it would not only leach out which could be beneficial to the erupting tooth and may also result in a mixture which resorbs at the same rate as the tooth. Chawla et al. in 2008, studied a mixture of ZnO, Ca(OH)2, and fluoride in the form of 10% NaF. The resorption rate of the material was found to be similar to that of the deciduous teeth. They then concluded that this might have been due to reaction of calcium hydroxide with fluoride resulting in the formation of calcium fluoride which not only induces radiopacity to the root canal filling material but also matched the resorption rate of the roots of deciduous pulpectomized teeth. However, this mixture consists of calcium hydroxide which is associated with resorption rate earlier than the root resorption, and eugenol is reported to cause periapical irritation. Hence, it was thought to assess the success and feasibility of a mixture of zinc oxide and 10% sodium fluoride. The need of the study was to establish the clinical and radiographic success of zinc oxide powder with 10% sodium fluoride as root canal obturating material.
| Methods|| |
The present study was conducted in the Department of Pedodontics and Preventive Dentistry, ITS-CDSR, Muradnagar, Ghaziabad, India with prior approval from the ethical committee of the institute. All the guidelines of the committee are conversant with the guidelines required for conducting clinical trials in India safeguarding the rights, safety, and well-being of the individuals being further in accordance with the guidelines laid out in the World Medical Association Declaration of Helsinki.
The sample comprised 30 primary molars in 4–9-year-old healthy children. The procedures, possible discomforts or risks, as well as possible benefits were explained fully to the human subjects involved, and their informed consent was obtained before the investigation. The teeth having the following signs and symptoms were included in the study: history of spontaneous pain, tenderness on percussion, grossly decayed primary molars, absence of fistula, evidence of radiolucency in the furcation or periapical areas, and hemorrhage that cannot be controlled within 5 min after pulp extirpation. The teeth which were not restorable, showing external or internal root resorption, extreme mobility, presence of fistula, gingival swelling, inadequate bone support, and perforated pulpal floor, were excluded from the study.
The abovementioned sample size is calculated according to the following formula:
Where Z = Z statistic for a level of confidence = 1.96
P = Expected prevalence or proportion (if the expected prevalence is 20%, then P = 0.2) d = Precision (if the precision is 5%, then d = 0.05).
Preparation of 10% sodium fluoride solution
10 g of sodium fluoride powder was mixed with 90 ml of distilled water (1:9) in a measuring cylinder to obtain 10% solution of sodium fluoride.
The root canal procedure involved primarily single-sitting pulpectomy, which was carried out by the same operator in all cases. Following administration of local anesthesia, the root canal treatment was carried out under rubber dam. After access opening [Figure 1], coronal and radicular pulp was removed [Figure 2]. Working length was established, and then, the canals were prepared with H-files (30–35 size), using a pullback motion. The canals were thoroughly irrigated with 3% sodium hypochlorite and saline and further obturated using a mixture of zinc oxide powder and 10% sodium fluoride.
The paste was subsequently carried with air-driven lentulospirals at slow speed into the canals [Figure 3]. The pulp chambers were then filled with fast setting ZnOE. Final restoration was done with stainless steel crowns on all the teeth [Figure 4]. Follow-up was done at 3-, 6-, 9-, and 12-month interval [Figure 5], and treatment success or failure was determined by the evaluation of clinical and radiographic findings.
The null hypothesis that was conceded for the study:
- There would be pain, mobility, intraoral swelling, postoperative draining sinus, and tenderness in all the teeth at the end of 12 months
- There would be inter-radicular radiolucency in all the teeth obturated with zinc oxide–10% sodium fluoride
- The rate of resorption of this mixture will not match the resorption rate to that of the tooth root.
The clinical and radiographic failures were recorded and subjected to statistical analysis using Chi-square test. Any teeth showing both clinical and radiographic success were recorded as overall treatment success.
| Results|| |
Clinically, the postoperative evaluation revealed that there was a reduction in clinical signs and symptoms, but it was not statistically significant (P > 0.05). Radiographic assessment showed progressive healing of radiolucency with the passage of time.
No teeth reported with pain during 12-month follow-up period except one tooth within 9-month interval. None of the teeth reported with mobility and intraoral swelling within 3-, 6-, 9-, and 12-month follow-up period. Within 3 and 6 months, no postoperative draining sinus was reported while one tooth within 9-month period and one more tooth within 12-month period reported with draining sinus postoperatively; however, the results were statistically not significant. One tooth each reported with postoperative tenderness within 9 and 12 month of 27 tender teeth preoperatively [Table 1].
Of 23 teeth which had preoperative inter-radicular radiolucency, it remained same in size in five (17.2%) teeth while it increased in one (3.4%) tooth and decrease in size was seen in four (13.8%) teeth within 3-month evaluation period. Radiolucency decreased in four (13.8%) teeth, remained of same size in other four (13.8%) teeth while increase was seen in two (6.9%) teeth within 6-month evaluation. Within 9- and 12-month evaluation period each, in two teeth (7.4%), radiolucency remained of the same size, and in one tooth (3.8%), it increased. However, radiolucency decreased in seven (25.9%) teeth within 9-month evaluation and in six (23%) teeth within 12-month evaluation [Figure 6]. The results were statistically not significant (P > 0.05).
|Figure 6: Postoperative inter-radicular radiolucency at 3, 6, 9, and 12 months|
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Six teeth showed root resorption in which material depleting from the root canal was at the same rate as that of the physiological resorption of the root [Table 2]. One canal was overfilled, but complete resorption was seen within 3-month evaluation. Clinical success rate was 100%, 100%, 96.4%, and 92.9% and overall radiographic success was 96.6%, 96.6%, 89.3%, and 85.7% at 3-, 6-, 9-, and 12-month interval, respectively [Figure 7] and [Figure 8].
|Table 2: Postoperative relative resorption of filling material with respect to root resorption at 12 months|
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|Figure 8: Clinical and radiographic success at 3-, 6-, 9-, and 12-month interval|
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Hence, the null hypothesis 1, 2, and 3 were rejected.
| Discussion|| |
The best space maintainer in both deciduous and mixed dentition is the deciduous tooth itself. Thus, preserving the integrity of deciduous dentition till they exfoliate themselves is important for adequate development of permanent dentition. Pulpectomy is thus considered as the best option for the retention of deciduous teeth. The term pulpectomy, in practice of pediatric dentistry, has come to mean removal of dental caries along with inflamed/necrotic material from pulp chamber and root canals, followed by obturation of root canals using resorbable root canal filling material.,
Various studies in the past have been carried out in quest to search for an effective filling material having rate of resorption that matches with that of the physiologic root resorption of the deciduous teeth leading to success of root canal treatment. Materials used for filling of root canals in deciduous teeth should ideally possess the optimum requirement of being antibacterial, resorbable at the same rate as that of the tooth root, and harmless to periapical tissues and developing permanent tooth bud. In addition, they should easily fill the canals, adhere to the walls, do not shrink, easily resorb if passed beyond the apex, be easily removed if necessary, be radiopaque, and cause no discoloration of the tooth.,,
ZnOE is the most widely used preparation for obturation of deciduous tooth pulpectomies with success rate ranging from 65% to 88.57%.,,, Despite the high success rates, ZnOE does not meet all criteria required for an ideal root canal filling material. Eugenol, in particular, has been reported to be cytotoxic and neurotoxic.,
Calcium hydroxide has been used either as a sole root filling material for deciduous teeth or in association with iodoform like in vitapex and metapex. It has a high pH after setting which provides a stimulus for tooth to repair itself and a wide range of antimicrobial activity against common endodontic pathogens. However, it resorbs earlier than the physiologic resorption of root.
Iodoform-based paste may produce a yellowish-brown discoloration of the tooth crowns which may compromise esthetics., Allergic reactions to iodine in some individuals have also been reported. Iodoform-based pastes have also been used in different formulations of root canal filling materials, namely Kri paste, Maisto paste, and Guedes-Pinto paste.
Endoflas has the advantage of having the resorption limited to excess material. Thus, the material is neither resistant to resorption nor it results in hollow tube effect. It also has a broad antibacterial efficacy. However, eugenol in endoflas may have irritating effects periapically.
Hence, the purpose of this study was to determine the clinical and radiographic success of zinc oxide integrated with 10% sodium fluoride as root canal filling material in primary teeth and thereby eliminating the adverse effects of other commonly used root canal filling materials.
Of the 27 teeth showing signs of pain and tenderness, only one tooth reported with pain, sinus, and tenderness on percussion and one tooth with sinus and tenderness on percussion within 9 and 12 months, respectively [Table 1]. The results of an in vitro study showed that codoping of zinc with fluoride ions produced an anti-inflammatory response.,, In the present study, similar kind of response with incorporation of combination of ZnO and NaF forming ZnF2 may have resulted in decreased pain.
Complete resorption of the overfilled material was seen within 3-month evaluation. Further, there were six teeth in which resorption of root started. However, in all six teeth, material matched the resorption rate of tooth root [Table 2]. In a similar study by Chawla et al., it was observed that the addition of sodium fluoride to calcium hydroxide and zinc oxide resulted in a mixture that matched the resorption rate of the roots of deciduous pulpectomized teeth.
Furthermore, codoping of hydroxyapatite with Zn 2+ and F − exerts antibacterial and antifungal effects against Escherichia More Details coli, Staphylococcus aureus, and pathogen yeast Candida albicans., Moreover, Zn–HA nanorods presented improved performance to decrease oral cavity bacteria which explains the absence of intraoral swelling and mobility in any case till the end of 12 months.,
Inter-radicular radiolucency decreased in all the individuals till the end of 12-month period except in two teeth where it remained the same and showed increase in only one tooth [Figure 1].
The in vitro study undertaken by Uysal et al. in 2014 also reported that codoping of Zn 2+ and F − ions into hydroxyapatite (HA) significantly improved its microhardness and had higher fracture toughness than pure HA. Furthermore, incorporation of Zn 2+ to the structure resulted in an increase in cell proliferation and alkaline phosphatase activity of cells, and further increase was observed with F − addition. This further adds to the advantages of the mixture of zinc oxide with sodium fluoride. In addition, fluoride may leach out which could be beneficial to the erupting tooth.
The overall clinical and radiographic success rate of the mixture of zinc oxide and 10% sodium fluoride was 92.9% and 85.7%, respectively, at the end of 12 months [Figure 2] and [Figure 3].
Thus, a mixture of zinc oxide with 10% sodium fluoride can be considered as a successful alternative material for obturation in primary teeth. The cost-effectiveness and easy preparation also contribute to its advantages. However, further studies with a longer follow-up need to be undertaken to authenticate its use as an effective root canal filling material for primary teeth.
| Conclusion|| |
- Rate of resorption of material has been found to match the resorption rate of the tooth root in the present study
- Excess material has been found to resorb during the study period
- Hence, sodium fluoride mixed with zinc oxide can be an effective alternative root canal obturating material for primary teeth.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2]