|Year : 2016 | Volume
| Issue : 2 | Page : 76-80
Efficacy of benzoic acid denture cleansing against the colonization of Candida albicans
Khalid Ahmad Omar Arafa
Department of Dentistry, Faculty of Applied Medical Sciences, Al Baha University, Al Bahah, Saudi Arabia
|Date of Web Publication||25-Oct-2016|
Khalid Ahmad Omar Arafa
Department of Dentistry, Faculty of Applied Medical Sciences, Al Baha University, P. O. Box: 1988, Al Baha
Source of Support: None, Conflict of Interest: None
Background: Although there are a diversity of methods proposed for cleaning complete dentures, there is still no consensus in the literature about which method is most effective for removing biofilm from acrylic resin denture base surfaces. Although chlorhexidine is mostly used, benzoic acid has emerged as an effective method of denture cleansing. This study aimed to examine the efficacy of denture soaks by benzoic acid against the colonization of Candida albicans compared to zordyl (chlorhexidine gluconate 0.2%). Materials and Methods: This is a randomized controlled trial conducted in Al-Azhar University, Assiut Branch, Faculty of Dentistry, in Egypt during a 4-month period. One hundred edentulous patients with complete dentures were assigned into two equal groups, group (1): Fifty patients given instructions to use benzoic acid for immersion of their dentures and they were given the prepared solution for free to be used, while group (2): Fifty patients used zordyl (chlorhexidine gluconate 0.2%) for denture immersion. The dentures were examined four times; before delivery of instructions, 1, 2, and 4 months after initial session of instructions. Results: It was found that household benzoic acid has inhibition effect against C. albicans. The differences in means of C. albicans counts between two groups were nonsignificant before the application of denture soaks, but they begin to be significant after 1 month of the application. The mean differences of C. albicans counts continue to be significant in the 2 nd and 4 th months of follow-up. Conclusion: This study showed that using benzoic acid for denture soak has an inhibition effects against the colonization of C. albicans on the surfaces of dentures more than using zordyl (chlorhexidine gluconate 0.2%).
Keywords: Candida albicans , chlorhexidine, cleansing, dentures, patients
|How to cite this article:|
Arafa KA. Efficacy of benzoic acid denture cleansing against the colonization of Candida albicans. Saudi J Health Sci 2016;5:76-80
| Introduction|| |
Denture stomatitis could be a common condition, findings from many studies recommended that it will have an effect on as several as 35-50% of wearers of complete dentures.  The rate of denture stomatitis among those using removable dental appliances varies from ten to seventy based on the population studied. 
Candida species play a major role in denture stomatitis and have been recognized in most patients, especially dentures wearers and can be divided into four basic stages. , Candida albicans were considered the biggest species isolated compared to other Candida species. Its prevalence has been reported at 11-67% in complete denture wearers.  Whether the organism is simply commensal during this situation remains a difficulty attributable to the frequency of such organisms within the general population. The etiology is best represented as complex, with the dentures considered the most etiologic issue. Candida biofilms were found to colonize cracks and imperfections of the acrylic resin denture.  The only real role of the organism because the etiologic issue in denture stomatitis is not fully explained. However, the presence of fungus organisms inside the biofilm lends credence to its role within the development and maintenance of denture stomatitis. 
A microbic plaque composed of yeasts accumulates on the fitting surface of denture plate and on the surface of hard palate. The local surroundings beneath the dental plate is a lot of acidic and fewer exposed to the cleansing action of spit, that favors higher candidal accelerator activity and will cause inflammation within the surface of hard palate. C. albicans is that the most typically isolated organism in these conditions. Using dental appliances, for example, dentures have found to alter the oral microflora. 
The cause is considered complex, with the prosthesis considered the leading cause. Night-time denture use habit, lacking oral and denture hygiene, and cigarette smoking are all main influencing factors to denture-induced stomatitis; however, none of these factors was the only factor of mucosal inflammation. , Nowadays, denture-related stomatitis could be defined as an inflammatory course of the mucosa that endures complete or partial removable dental appliances dentures.  It is more likely to develop when the denture is left constantly in the mouth, rather than taken away during sleep, or when it is not cleaned regularly.  The major risk issue for the event of this condition is using upper complete dentures, notably when it is not removed throughout sleep and cleans routinely. Alternative factors embrace dryness, diabetes mellitus, or a high carbohydrate diet. Human immunodeficiency virus could seldom be an associated factor.  Although there are a diversity of methods proposed for cleaning complete dentures, there is still no consensus in the literature about which method is most effective for removing biofilm from acrylic resin denture base surfaces; however, the use of chlorhexidine has been reported to reduce plaque levels significantly compared to other gums.  Multifactorial etiology of denture stomatitis makes the treatment complex and many factors are considered such as control of denture plaque, usage of antifungals, and removal of denture before sleeping. Mainly mouth rinses, denture soaks, and dentures reline with or without mechanical cleaning were used to control of denture plaque.  Some studies reported that microwave irradiation is effective in control of denture plaque. ,
The most commonly used mouth rinses and denture soaks agents include chlorhexidine gluconate, sodium hypochlorite, peroxides, alcohol-based mouth rinses, and antifungal mouth rinses. This study was aimed to examine the effectiveness of a new denture soaks (benzoic acid 0.5% with sodium chloride 0.9%) on the colonization of C. albicans on the dentures surfaces compared to the zordyl (chlorhexidine gluconate 0.2%).
| Materials and methods|| |
This is a randomized controlled trial. It was conducted in Al-Azhar University, Assiut Branch, Faculty of Dentistry, in Egypt during 4 months (from April 2013 to August 2013). One hundred edentulous patients were selected by simple random sampling. All patients in the study have the following criteria: Age >50 years, have complete dentures made of heat cured acrylic resin; and they provided a written consent to participate in the study. Exclusion criteria were as follows: Diabetic, anemic, patients subjected to radiotherapy or chemotherapy, patients who have been underwent to antifungal or steroids treatment in past 3 months, and immunodeficiency patients. One hundred completely edentulous patients participated and were randomly assigned into two equal groups, each consisted of fifty patients: Group (1): Fifty patients given instructions to use benzoic acid for household cleansing of their dentures and they were given the solution to be used, while Group (2): Fifty patients used zordyl (chlorhexidine gluconate 0.2% for household cleansing of their dentures and they were given the solution to be used. The dentures were examined four times; before instructions were delivered, after 1 month, 2 months, and finally 4 months of initial instructions.
The intervention consisted of daily use of benzoic acid 0.5% with sodium chloride 0.9% for denture immersion, while control group used zordyl (chlorhexidine gluconate 0.2%). The solution for intervention group was prepared at the Al-Azhar University, Assiut Branch, Faculty of Dentistry in Egypt; 500 ml sodium chloride and 2.5 g benzoic acid were dissolved in this solution. The instructions were to immerse denture in the prepared solution and control solution for 30 min daily, in addition to the removal of denture at night.
The data were collected from the two groups by questionnaire for demographic characteristics and by collecting denture swabs for C. albicans isolation. Denture swabs were collected from fitting surface of upper dentures and inoculated in Sabouraud's dextrose broth, peptone (1%), and blood agar media. The culture plates were incubated at 37° C for 24-48 h. The supposed isolates of Candida were sub-cultured on Sabouraud's agar plates. The suspected strain of Candida albicans was injected in human serum for germ tube creation. After the incubation period, the C. albicans colonies were collected and examined. Investigation of Candida collected samples from the dentures were cultured on CHROMagar Candida plates. The subjects rinsed with 10 mL of phosphate-buffered saline for 15 min, and 100 μL of collected buffer were seeded on the plates, and then cultured for 48-72 h at 37°C. Candida species were determined as colony-forming units (cfu) for each individual. Characteristically, C. albicans exhibited green, Candida tropicalis exhibited purple, and Candida glabrata exhibited dark pink colors. Geotrichum species, unlike C. albicans, formed small, rough colonies of pale green appearance. The colonies were collected, examined, and counted.
Clinically, the patients were examined four times; at delivery of instruction and distribution of benzoic acid for patients, after 1 month, 2 months, and finally 4 months. The denture stomatitis was classified into three classes: 0 = good (absence of inflammation), 1 = fair (moderate or isolated regions of inflammations or ulceration), 3 = poor (generalized inflammation or ulceration).
This study was approved by the Dental Health Department at the Faculty of Applied Medical Sciences, Al Baha University (attached). The consents forms were filled by all participants.
The data were then analyzed by computerized methods; (Statistical Package for Social Sciences) (SPSS version 20 IBM Corp., Armonk, New York, USA). The Chi-square test was used to analyze the differences in participants' demographic characteristics. The independent t-test was used to analyze the difference in mean of colonization counts between the two groups. Paired sample t-test was used to measure the differences in means of colonization count before and after intervention. All values were tabulated as averages (mean) cfu/ml with standard deviation. P < 0.05 was considered statistically significant with level of confidence 95%.
| Results|| |
As shown in [Table 1], one hundred edentulous patients participated in this study. They are homogeneous in their demographic characteristics. Their education levels vary between primary and secondary levels. For patients participated in the two groups, there were insignificant differences in the variables of age, education level, gender, smoking, and dryness (P > 0.05).
|Table 1: Characteristics of group 1 and group 2 edentulous patients participated in the study. (n=100, n1=50, n2=50)|
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The differences in means of C. albicans counts between two groups were nonsignificant before the application of denture soaks, but they begin to be significant after 1 month of the application. The mean differences of C. albicans counts continue to be significant in 2 nd and 4 th months of follow-up [Table 2].
|Table 2: Comparing the means and standard deviations of Candida albicans counts between the two groups. (n=100, n1=50, n2=50)|
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C. albicans counts in Group 1 were not changed significantly (0.01 cfu/ml before instructions versus 0.03 cfu/ml at the 4 th month; P = 0.12). The 95% confidence interval for the difference of means was ranging from 0.01 cfu/ml to 0.03 cfu/ml. The findings from Group (2) showed that the mean of C. albicans was significantly increased from 0.02 cfu/ml at delivery of instructions to 0.5 cfu/ml after 4 months, P = 0.03 [Figure 1].
|Figure 1: Comparing the means of Candida albicans counts before and after cleansing between the two groups. (n=100, n1=50, n2=50)|
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Denture stomatitis in the intervention group at 4 th month was found in only - 6% of patients and all were classified as fair. The denture stomatitis was found to be 50% in group (2). These findings showed that the differences in denture stomatitis was significantly high in control group, P = 0.00 [Table 3].
|Table 3: Comparing Candida albicans degree on dentures in the two groups after 4 months. (n=100, n1=50, n2=50)|
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| Discussion|| |
This study was conducted among two homogenous groups in relation to age, gender, level of education, smoking, and xerostomia, in order to examine the efficacy of household denture cleansing using benzoic acid 0.5% with sodium chloride 0.9% on the colonization of C. albicans on the dentures surfaces compared to the zordyl (chlorhexidine gluconate 0.2%). Treatment of denture associated stomatitis is complex and many chemical and physical methods have been used to the prevention and control of the denture plaque. These methods include antifungal agents used topically or systematically, disinfectant chemical agents, brushing of denture surface, and microwave irradiation.  The two agents that have used in the current study to control of the denture plaque are belonging to chemical disinfectant methods. The benzoic acid 0.5% with sodium chloride 0.9% is a new intervention where no previous studies have estimated its effect, while the control group (chlorhexidine gluconate 0.2%) is a commonly used disinfectant agent in the control of denture stomatitis. In another study, found that as chlorhexidine gluconate is by far the commonest antiseptic mouth wash prescribed in dentistry.  Listerine is a widely used mouth wash containing benzoic acid 1.5 mg with other alcohols such as ethanol 0.26 mL, thymol 0.63 mg, eucalytol 0.9 mg per each mL of listerine. A study compared the effects of listerine (as a mouth rinse and denture soak) with soft relining of upper denture has found the reduction of denture stomatitis in both groups.  These findings are in agreement with the current study findings where denture stomatitis in benzoic acid group was found only in 6% after 4 months of denture soaking, and all cases of denture stomatitis were classified as fair inflammation. While in control group used chlorhexidine gluconate 0.2%, denture stomatitis was found in 50% of patients, where 14% were classified as poor inflammation. These findings showed that the C. albicans was significantly high in the chlorhexidine gluconate 0.2% group compared to benzoic acid group. Hunter et al. conducted in vivo study by the administration of a mouth rinse (0.2% chlorhexidine gluconate) three times daily. They found a significant effect against denture plaque, but no effect on number of Candida organisms, which could explain why denture stomatitis was much higher among chlorhexidine group in the findings of the current study.  On the other hand, Kadir et al. conducted in vitro study and they reported the antifungal effect of chlorhexidine gluconate 0.2% on C. albicans isolated from oral cavity of patients with denture stomatitis.  Lal et al. found that chlorhexidine (in the peridex solution) as a mouth rinse and a denture soak had completely removed C. albicans from denture surface and the palatal inflammation was also significantly decreased. However, many weeks after the peridex therapy was stopped, C. albicans recurred again.  In the current study, the results showed no significant difference in mean of C. albicans counts between the two groups at the beginning of the study. Almost all the study subjects are elderly, their ages over 60 years. This fungus is more frequent among older people, as they were likely to use removable dentures. However, there are some reports that could not prove significant variations within the prevalence consistent with the age of the participants. Paradoxically, many authors have delineated a big fall within the prevalence of denture stomatitis among elderly. The highest rate, though, has been noticed among elderly. 
In addition, soaking denture in a solution of 0.02% sodium hypochlorite has been found to reduce the denture plaque effectively. But immersion of the denture in sodium hypochlorite for an intermediate period of time has a destructive effect on the denture base material. Another in vitro study was conducted to compare the effect of several chemical and physical agents in control of C. albicans. The findings showed antifungal effects only with soaking in sodium hypochlorite solution, microwave irradiation with denture immersed in water, and usage of effervescent cleansing tabs.  These results were consistent with the findings of many other in vitro studies. ,,
The findings of the current study were also comparable to findings from study done in Turkey that tested the effect of different cleaning means against the settlement of Candida species, which reflected that Klorhex and fittydent have positive preventive properties on the settlement of Candida species on the dentures surface and the palatal membrane. 
On the other hand, this study was in contrast to one study conducted in the Republic of Korea in 2014, to assess the effect of denture cleansers on C. albicans formation over resilient liners. It was found that it is not recommended to immerse specific dentures in cleansers.  There were also many reports to suggest the relations of surface roughness and C. albicans adherence to dentures which could be reduced by cleansing. 
There are several studies investigated the adhesion of C. albicans to denture acrylic resin due to association of commensal opportunist pathogen yeast with denture-induced stomatitis. 
The strengths of this study include the initiation of free cleansing solution for households cleansing for denture wearers, using low price solution and the long evaluation period (4 months). The study limitations were as follows; the study was conducted among only 100 patients; such studies will yield more useful results if conducted on more sample size with randomization.
The free distribution of benzoic acid 0.5% with sodium chloride 0.9% with instructions for daily cleansing has significant preventive measures and cost-effective benefits on reducing the colonization of C. albicans on dentures, which are sequentially efficient and cost effective.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]