|Year : 2018 | Volume
| Issue : 3 | Page : 190-194
Antibacterial property of eugenol and eugenol-free zinc oxide cements incorporated with various concentrations of sodium fluoride
Aastha1, Keshav Kumar Gautam2, KN Raghavendraswamy3, Anil Kumar Gujjari3, Meenakshi Sharma4
1 Department of Prosthodontics, Rishiraj Dental College and Hospital, Bhopal, Madhya Pradesh, India
2 Department of Pedodontics, Rishiraj Dental College and Hospital, Bhopal, Madhya Pradesh, India
3 Department of Prosthodontics, JSS Dental College and Hospital, Mysore, Karnataka, India
4 Department of Pedodontics and Preventive Dentistry, Government Dental College, Jaipur, Rajasthan, India
|Date of Web Publication||24-Sep-2018|
Keshav Kumar Gautam
Department of Pedodontics, C27/111, B-3, Jagatganj, Varanasi - 221 002, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Background: Restoring tooth by fixed partial dentures involves tooth reduction to reproduce the dental anatomy in the prosthesis. This process brings about the exposure of millions of dentinal tubules which serves as potential passageways for the diffusion and colonisation of bacteria. Aim: To evaluate and compare the antibacterial property of eugenol and eugenol-free zinc oxide cements incorporated with various concentrations of sodium fluoride. Materials and Methods: Circular specimens of zinc oxide eugenol (ZOE) and eugenol-free zinc oxide cements were prepared with and without incorporation of sodium fluoride at various concentrations. The antibacterial property of the cement specimens was evaluated against Streptococcus mutans using disc diffusion method. Zone of inhibition which was formed under anaerobic conditions after a period of 48 h was recorded. Results: The difference in antibacterial property of ZOE cements and eugenol-free zinc oxide cements containing sodium fluoride was statistically highly significant at all the concentrations of sodium fluoride. Eugenol-free zinc oxide did not show any antibacterial property at all. The different percentages of fluoride concentrations, that is, 1% and 2%, did not show significant difference statistically. Conclusion: Eugenol-free zinc oxide cement did not have any antibacterial effect with or without fluoride. Eugenol-containing zinc oxide cement with sodium fluoride had maximum antibacterial properties. Eugenol-containing zinc oxide cement exhibited antibacterial properties of its own.
Keywords: Antibacterial property, disc diffusion test, eugenol-free zinc oxide, sodium fluoride, Streptococcus mutans, zinc oxide eugenol
|How to cite this article:|
Aastha, Gautam KK, Raghavendraswamy K N, Gujjari AK, Sharma M. Antibacterial property of eugenol and eugenol-free zinc oxide cements incorporated with various concentrations of sodium fluoride. Adv Hum Biol 2018;8:190-4
|How to cite this URL:|
Aastha, Gautam KK, Raghavendraswamy K N, Gujjari AK, Sharma M. Antibacterial property of eugenol and eugenol-free zinc oxide cements incorporated with various concentrations of sodium fluoride. Adv Hum Biol [serial online] 2018 [cited 2020 Jul 13];8:190-4. Available from: http://www.aihbonline.com/text.asp?2018/8/3/190/241930
| Introduction|| |
Restoring tooth by fixed partial dentures (FPDs) involves tooth reduction to reproduce the dental anatomy in the prosthesis. This process brings about the exposure of millions of dentinal tubules which serve as potential passageways for the diffusion and colonisation of bacteria. To minimise this, after the tooth preparation is done, the patient is invariably provided with protection through provisional restorations which are luted with provisional cements. Furthermore, during the initial treatment phase, periodontal treatment, orthodontic and diagnostic procedures may be required before the definitive restorative phase. Therefore, provisional restorations have to be placed with provisional cements for an extended period. In such situations, provisional cements are susceptible to wash out, marginal leakage, bacterial infiltration and molecular penetration.,
In addition to this, teeth already infected with minute carious lesion will be debrided, but the bacterial contamination may persist beneath the underlying dentine.
In an attempt to protect abutment teeth from bacteria, studies have examined the possibility of adding antibacterial agents to the dental cements.
The most common cements used in provisional fixed prostheses are that containing zinc oxide eugenol (ZOE). The crowns are easy to remove from the prepared tooth have a low cost, and has been proved to have obtundent effects on dentinal hypersensitivity. Unfortunately, ZOE alters the polymerisation of some resins used both in provisional prosthesis and in the reconstruction of the core. This has led to the introduction of eugenol-free products.
Evidence from different studies showed that materials which release fluoride have anticariogenic potential. Fluoride inhibits the growth of many bacteria including Streptococcus mutans. Many studies have been undertaken in which fluorides have been added to the eugenol cement, but there have been very few studies on eugenol-free zinc oxide cements incorporated with fluorides and also comparison between eugenol and eugenol-free zinc oxide cement with regard to antibacterial property.
Hence, the purpose of this study was to incorporate fluoride in eugenol and eugenol-free zinc oxide cements and compare their antibacterial property thereafter.
| Materials and Methods|| |
Circular specimens of 6 mm diameter and 1 mm thickness were fabricated of eugenol and eugenol-free zinc oxide cements with and without incorporation of fluoride using a metal mould. A total of 72 specimens were fabricated and divided into two groups. Group I consisted of zinc oxide cement powder with eugenol liquid and Group II contained eugenol-free zinc oxide cement. Each group had three subgroups with 12 specimens per subgroup. Sodium fluoride was added at 1% and 2% to the zinc oxide component for subgroup B and C of both the groups. This was followed by homogenisation. No fluoride was added for subgroup A.
The powder and liquid ratio was predetermined for ZOE. The mixing was done by a stiff spatula by folding method to form a homogenous mix. The prepared zinc oxide paste was dispensed and mixed with the reactor paste as per the manufacturer's instructions with a stiff stainless steel spatula.
The metal mould had three parts. They were upper member, a lower member and a spacer of 1 mm thickness. The spacer had holes which were 6 mm in diameter. The lower member of the mould was covered with a cellophane sheet over which spacer was placed. The mixed cement was packed into the mould. Extra cement was removed with a flat instrument. Another cellophane sheet was placed over the mould with packed cement specimens and the upper member was placed over it. Three minutes from the start of mixing, the mould along with the packed specimens was placed into the incubator having a relative humidity of 95%–100% at a temperature of 37°C which confirms to the alginate dialdehyde specifications. After 1 h, the mould along with the packed specimens was withdrawn from the incubator. The specimens were retrieved from the mould after the cement had set. The specimens were sterilised using ultraviolet steriliser.
Lawn culture of S. mutans (ATCC-25175) was done on the sterility-checked sheep blood agar plates. Agar plates were inoculated with the bacteria using sterile cotton swabs. Two plates were taken for each group. Each Petri dish More Details was divided into four parts. Sterile cement specimens were introduced from each subgroup into the plate for each group using a sterile forceps. In addition an antibiotic disc (linezolid), a positive control was also introduced into the plate. The agar plates with the specimens were incubated in an anaerobic jar for 48 h at 37°C and observed for the inhibition of bacterial growth around the specimens. Zone of inhibition was measured at its widest part in millimetres using a scale [Figure 1] and [Figure 2].
| Results|| |
The mean score values and standard deviations are presented in [Table 1]. The overview of mean zone of inhibitions of eugenol and freegenol cements have been presented in the [Graph 1].
|Table 1: Comparison of mean zone of inhibitions of Group 1 and Group 2 cement specimens after 48 h of incubations|
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Group 1 specimens showed the highest value for the mean zone of inhibition. Group 2 specimens did not show any zone of inhibitions.
T-test was done to evaluate the difference between the means.
[Table 2] shows difference in mean zone of inhibitions of subgroup A (0% sodium fluoride) and subgroup B (1% sodium fluoride) for Group 1 (eugenol-containing zinc oxide cement); results showed that the difference of means between the subgroups was statistically highly significant P: 0.00001 (P < 0.05). [Table 3] shows the mean difference between zone of inhibitions of subgroup A (0% sodium fluoride) and subgroup C (2% sodium fluoride) for Group 1 (eugenol-containing zinc oxide cement) and the test showed the result to be statistically highly significant P: 0.00001 (P < 0.05). [Table 4] shows the mean difference between zone of inhibitions of subgroup B (1% sodium fluoride) and subgroup C (2% sodium fluoride) for Group 1 (eugenol-containing zinc oxide cement) and the result was statistically not significant P: 0.583 (P > 0.05).
|Table 2: Comparison of mean zone of inhibitions of subgroup A (0% sodium fluoride), subgroup B (1% sodium fluoride) of Group 1 (eugenol-containing zinc oxide cement)|
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|Table 3: Comparison of mean zone of inhibitions of subgroup A (0% sodium fluoride), subgroup C (2% sodium fluoride) of Group 1 (eugenol-containing zinc oxide cement)|
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|Table 4: Comparison of mean zone of inhibitions of subgroup B (1% sodium fluoride), subgroup C (2% sodium fluoride) of Group 1 (eugenol-containing zinc oxide cement)|
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| Discussion|| |
The FPDs using metal and ceramics which closely reproduce the natural form of teeth in the prosthesis bring about a higher reduction of dental tissue to gain aesthetic results. This causes the exposure of millions of dentinal tubules. Each tubule contains the cytoplasmic process of a cell body (the odontoblast), whose nucleus is in the pulp cavity. These tubules are potential passageways for the diffusion and colonisation of bacteria. Unless the environment around the exposed dentin is carefully controlled, adverse pulp effects can be expected. In addition, bacteria that could not be completely eradicated from the pre-existing lesions may remain in the deeper layers of dentine invading the pulp tissue.
Provisional restorations cemented by temporary cements thus seal and insulate the prepared tooth surface from the oral environment to prevent sensitivity and further irritation to the pulp.
Furthermore situations such as full mouth rehabilitation, restorative phase of implant reconstructive procedures, temporomandibular joint dysfunction therapy and unforeseen events such as laboratory delay or patient's unavailability may also lead to the need for long-term provisional restoration. In such situations, provisional cements are susceptible to cement washout, marginal leakage, bacterial infiltration and caries.
Eugenol-containing and eugenol-free zinc oxide cements are one of the most popularly used provisional cements. Thus, the present study had been undertaken to evaluate the antibacterial property of eugenol-containing and eugenol-free zinc oxide cements owing to its frequent use in the fixed prosthodontic therapy.
The results of this study showed that although fluoride is one of the most popular antibacterial agents, it was unable to impart any antibacterial properties to eugenol-free zinc oxide cement. However, for the eugenol-containing zinc oxide cement, fluoride had an additive effect on its antibacterial property. The different percentages of sodium fluoride that is 1% and 2% added to ZOE did not show any significant difference statistically as shown by the zone of inhibitions at the end of 48 h. Eugenol exhibited its own antibacterial while freegenol did not have antibacterial property of its own. Many similar studies had been conducted before. They have mainly studied the effect of addition of fluoride to eugenol and eugenol-free zinc oxide cement on other properties of the cements as well as remineralisation and solubility of enamel. Lewienstiel et al. investigated the retention, solubility and microleakage of provisional crowns cemented with temporary cements to which stannous fluoride (SnF2) was added.
Shwartz et al. showed the effect of zinc oxide-eugenol formulations to which sodium fl uoride or SnF2 was added on solubility of enamel and found a reduction in solubility of enamel in contact of modifi ed ZOE cements.
Shwartz also showed the effect of zinc oxide-eugenol cement containing monofluorophosphate (MFP) on fluoride uptake and solubility of enamel. The results of the study indicated that by incorporating a fluoride compound such as MFP into ZOE cement, the enamel fluoride concentration is increased significantly as the ZOE slowly disintegrates in the oral environment. Studies on the effect of addition of fluoride on eugenol and eugenol-free zinc oxide cement on its antibacterial property are sparse. However, many studies have shown that fluoride-releasing materials have antibacterial property.
The antibacterial effect of fluoride-releasing sealants was estimated by Loyola-Rodriguez et al. using agar plates infected with several strains of S. mutans and Streptococcus sobrinus and it was concluded from the study that Teethmate-F sealant was the only sealant tested that inhibited S. mutans and S. sobrinus and this was due to the fluoride released by the sealant.
They conducted a similar study to identify the factors involved in the antibacterial activity of glass ionomer cement (GIC) on mutans streptococci. The antibacterial effect of GIC was estimated using agar plates infected with strains of S. mutans and S. sobrinus. It was concluded that fluoride has both direct and indirect effect on the bacterial cell of mutans streptococci, causing inhibition of acid production and electrolyte metabolism in vitro. Apart from this, fluoride has other benefit of preventing dissolution of enamel and promoting remineralisation.
As per Annete et al., the elution of fluoride is a complex process. It can be explained by several intrinsic variables such as formulation and fillers. It is also affected by experimental factors i.e., storage media, powder–liquid ratio, mixing procedure, setting time and amount of area exposed. It also depends on the type and permeability of material and the type and concentration of fluoridating agent. Fluoride release on the application of fluoridating agent may partly occur by the washout of fluoride ions that are retained on the surface or the pores of the restorative materials.
The release of fluoride from eugenol can be explained from the setting reaction of ZOE cement. When eugenol is mixed with zinc oxide, a chelation reaction occurs and zinc eugenolate is formed. When examined ultrastructurally, usually ZOE cement contains grains of zinc oxide embedded in a zinc eugenolate mix. Because separate zinc eugenolate units are held together by Vanderwaal forces and particles interlocking ZOE cements are weak mechanically, when exposed to aqueous media, such as saliva or dentinal fluid, hydrolysis of zinc eugenolate occurs yielding eugenol and zinc hydroxide. Thus, release of fluoride from ZOE and not from the freegenol can be explained on the basis of loosely bound water and solutes in the porosities of ZOE which may be exchanged with an external medium by passive diffusion.
The cement matrix in eugenol-free zinc oxide cement might not have provided a pathway for the exchange of fluid. The tight bonding between the cement matrixes might have decreased the permeability compared to the weak Vanderwall forces of the eugenol. The ingredients of freegenol might also be the reason preventing the release of fluoride.
The limitation of the study included the inability of the test to correlate the release of fluoride and inhibition of bacterial growth over a period of time. This test was unable to determine the minimum inhibitory concentration of fluoride for bacterial inhibition precisely.
Further studies can be conducted to enhance the retentive properties of ZOE cements modified with fluorides. Freegenol cements can be further tested with various other agents to impart antibacterial properties.
| Conclusion|| |
Within the limitations of this study, following conclusions can be drawn:
- ZOE with incorporation of 1% and 2% sodium fluoride showed the maximum antibacterial property. One percentage of sodium fluoride was enough to impart antibacterial properties to ZOE cement as there was no significant difference in the antibacterial property of ZOE incorporated with 1% and 2% sodium fluoride
- Eugenol-free zinc oxide cement with 1% and 2% sodium fluoride had no antibacterial property. The addition of fluoride did not have any effect on its antibacterial property.
- ZOE exhibited antibacterial property of its own
- Eugenol-free zinc oxide cement did not exhibit antibacterial property of its own.
Clinical implication of this study is that in patients who are more prone to caries or clinical situations where long-term provisionalisation is required. It is better to have a provisional cement with antibacterial property to prevent the teeth from the cariogenic effects of bacteria. Preservation of the tooth structure left is always better than the restoration of what is lost.
We would like to acknowledge Dr. Lancy Dsouza and Dr. Keshav.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]