Tajmulla Ahmed1*, Abhilash A2, Pramod RC3, Fawaz Pullishery4, Gufaran Ali Syed5 and Mohammad Jaffar6
 
1 Department of Prosthodontics, Batterjee Medical College, Jeddah, KSA, Email: [email protected]
2 Department of Prosthodontics, Sharavathi Dental College And Hospital, Shimoga, India
3 Department of Oral Pathology, Batterjee Medical College, Jeddah, KSA
4 Department of Community Dental Practice, Batterjee Medical College, Jeddah, KSA
5 Division of Endodontics, Batterjee Medical College, Jeddah, Saudi Arabia
6 Department of Pharmacology, Batterjee Medical College, Jeddah, KSA
 
*Correspondence: Associate Professor. Tajmulla Ahmed, Department of Prosthodontics, Batterjee Medical College, Jeddah, KSA, Tel: +966531045590, Email: [email protected], [email protected]

Citation: Ahmed T, et al. Comparison of Candidal Growth & Chlorhexidine Efficacy on Complete Denture-Biofilms of Patients with & without Denture Stomatitis - An in vivo Study. Ann Med Health Sci Res. 2019;9:741-753

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Abstract

Background: Denture stomatitis is highly prevalent in denture wearing patient, & microbial plaque accumulation on intaglio surface of removable dentures plays a critical role in formation of denture biofilm. The purpose of this study was to evaluate the growth of candidal species on Denture Biofilm using new sampling technique in vivo & testing efficacy of Chlorhexidine as disinfectant on denture biofilm of patients with & without denture stomatitis. Methods: Patients wearing complete dentures with partial denture stomatitis as study group & patients without denture stomatitis as control group were taken. Separate acrylic resin disks were inserted at denture stomatitis lesion site and at normal mucosal sites coinciding with the dentures of study group & control group. After 24 hours and 3 days of wear of dentures, the disks were retrieved and compared for number of candidal colony forming unit (CFU)s per ml of samples & efficacy of 0.5% Chlorhexidine (CHX-0.5%) on same samples from the lesion & normal mucosal sites respectively. Results: The No. of Candidal (CFU)s count on denture biofilm increased exponentially from day-1 to day-3 with statistically highly significant order at lesion site & with statistically significant order at non-lesion site of denture stomatitis patients. 0.5% Chlorhexidine was found to be very effective & of statistically highly significant order in reducing the fungal load at lesion site of denture stomatitis. Conclusion: The complete dentures can be soaked in CHX-0.5% for specific time period to treat or to avoid denture stomatitis in denture wearing patients.

Keywords

Chlorhexidine; Denture stomatitis; Denture biofilm

Introduction

Oral candidiasis, also known as Denture stomatitis, is the chronic inflammation of Denture bearing area which occurs in 25-65% of Denture wearers. It is a term used to describe inflammatory changes in the oral mucosa of Denture-bearing tissues, characterized by erythema, found under complete or partial Dentures in both jaws, but more frequently in the maxilla [Figure 1].[1] These lesions are very frequent complications for the wearing of removable Dentures both in independent and frail, or dependent elderly adults.[2] The behavior of oral mucous membrane in contact with Dentures has been the subject of considerable interest. Microbial plaque accumulation on intaglio surface of removable Dentures plays a critical role in the formation of Denture biofilms. Studies have reported an association between candida species & Denture stomatitis. For the first time, Cahn suggested that candida albicans as the causative agent of Denture stomatitis.[3] As the association between candida species & Denture stomatitis exits, targeting microbes such as candida species overDenture biofilm at different stages in its development may result in better understanding of the relationship of inflammation in candidainduced Denture stomatitis.[4] Consequently, the treatment of Denture stomatitis includes correcting Denture faults, improving Denture hygiene and prescribing antifungal agents. The candida cells are significantly less susceptible to antiseptics & antifungal agents, & their mechanism of resistance is not fully understood.[5] Chlorhexidine is commonly used by dental patients as antiseptics.[6] Its efficacy on Denture biofilm needs to be tested and compared.

amhsr-localized

Figure 1: Partial or localized denture stomatitis lesion on palatal mucosa.

The purpose of this study is to evaluate the growth of candida species within the Denture biofilm using new sampling technique in vivo and testing whether 0.5% Chlorhexidine 0.5% CHX is effective as a disinfectant on Denture biofilm in patients having Denture stomatitis & in patients not having Denture stomatitis.

Methods

Study design

The proposed study was conducted to isolate the samples of Denture biofilm formed periodically on the acrylic resin disks which were inserted on the intaglio surface of complete Dentures. The patients with Denture stomatitis & the patients not having Denture stomatitis were allowed to wear the modified complete Dentures for a specific time period of 24 hours and 3 days periodically. The samples isolated were cultured to compare for the presence of colonies of candidal species & to quantify their differential load on the Denture biofilm samples obtained. Then the efficacy of 0.5% CHX against candidal species cultured from various samples of Denture biofilms was evaluated. The pictorial representation of group distribution of study samples was shown in [Figure 2]. Thirty patients wearing complete Dentures for at least five years were selected with their written consent for the research work. Fifteen patients having localized or partial Denture stomatitis were considered as the experimental or study group:[Group-A]. The biofilm samples obtained from acrylic resin disks of Dentures contacting the Denture stomatitis lesion site & the normal site of the palatal mucosa of Denture stomatitis patient was termed as Group-Al samples, & Group-A2 samples respectively. Remaining fifteen patients not having Denture stomatitis were considered as Control group:[Group-B], here the biofilm samples obtained on acrylic resin disks, contacting the palatal mucosa of patients not having Denture stomatitis was termed as Group-B samples. The subjects excluded from the study were, patients with generalized Denture stomatitis, patients with a history of relevant systemic diseases like diabetes, anemia etc., which promotes Denture stomatitis & also the patients who were on immunosuppressive drugs.

amhsr-representation

Figure 2: The pictorial representation of group distribution of study samples.

Fabrication of removable acrylic resin disks inlay samples

Discs of pink modeling wax (Rolex, Ashoo sons, Delhi, B. No. MW 29) of 3x3 mm diameter and 2 mm thickness were punched from a sheet using a cork borer. Four wax discs per study group & two wax discs per control group were flasked and heat cured. The disks were de-flasked and stored in water to prevent the possibility of dimensional changes. After the routine finishing & polishing procedures commonly used in clinical prosthetic dentistry, all samples were rinsed in distilled water, ultrasonicated twice (ULTRAsonik, Ney 28B) in distilled water for 15 min, & then rinsed once more. The disk specimens were then stored in distilled water at 37°C & water was changed every 2 days.

Method of Collection of Data

Removable acrylic resin disk inlays of 3 mm diameter in size which were custom-made were retained in the holes on intaglio surface of existing Dentures of Group-A & B patients with selfcure acrylic resins & later the Dentures were polished at that particular site. Participants were instructed to wear the Dentures with disks for the study period of total three days. Four disks were inserted to receive samples from Group-A1, and two disks were inserted to receive samples from Group-A2 [Figure 3]. After 24 hrs one disk was retrieved from the lesion site & another from normal site. After three days remaining one disk was retrieved from the lesion site & another from normal site. Only two disks were inserted to receive samples from Group-B where one disk was retrieved after a period of 24 hours & another disk after 3 days [Figure 3]. The retrieval of disk samples was done without disturbing the biofilm on intaglio surface of the disk. After the study was completed the holes in the Dentures were repaired by self-cure acrylic resin.

amhsr-dentures

Figure 3: Site of location of disks in dentures of sample group’s patient.

Inoculation

Each of the retrieved disks from Dentures of both groups was cleaned sonically in distilled water by agitation for 15 seconds to remove salivary debris. The biofilm formed on the disks was scraped thoroughly with sterile B.P. blades separately and then diluted in normal saline in two separate test tubes.

To test the efficacy of 0.5% CHX (Chlorhex, Universal medical supplies Co, US.) on candidal species of biofilm, 10 ml each of biofilm samples taken from both the groups samples retrieved after 24 hours and after 3 days were inoculated with 10 ml of 0.5% CHX, incubated at 37°C for 24 hours & sub-cultured on two halves of Sabouraud Dextrose Agar (SDA) plates & incubated as before & the growth was quantified (CFU/ml) and compared separately [Figure 4].

amhsr-candidal

Figure 4: Comparative candidal growth from biofilm samples on SDA plates.

The results obtained from the above study were collected, tabulated and statistically analyzed.

Results

Descriptive comparison of Means & Std. Deviation of No. of candidal (CFU)s between (b/w) & within study & control groups, with & without application of 0.5% CHX on 1st & 3rd day samples was done [Table 1]. The No. of candidal (CFU)s without CHX at lesion site on 3rd day was more than 5.7 log10 candidal (CFU)s which was reduced to 2.5 log 10 candidal (CFU)s with an application of 0.5% CHX. Thus fungal load was reduced to 4 log10 candidal (CFU)s with an application of 0.5% CHX. Similarly, the comparison on 1st day with & without 0.5% CHX shows that the fungal load was reduced to 2 log10 candidal (CFU)s. The samples from the non-lesion site when compared for means of No. of candidal (CFU)s, with & without 0.5% CHX, the fungal load was reduced to 0.7 log 10 candidal (CFU)s for the 1st day and was reduced to 1.9 log 10 candidal (CFU)s for the 3rd day. The samples from group-B when compared for means of No. of candidal (CFU)s, with & without 0.5% CHX, the fungal load was reduced to 0.25 log10 candidal (CFU)s for the 1st day and to 1.0 log10 candidal (CFU)s for the 3rd day.

Descriptive
  N Mean Std. Deviation Minimum Maximum
Without CHX Day 1 With lesion
Without lesion
Control
15
15
15
2.8177
0.9670
0.4000
1.90056
1.42911
1.08815
0.00
0.00
0.00
4.78
3.30
3.70
Day 3 With lesion
Without lesion
Control
15
15
15
5.7513
2.5757
1.4708
3.87046
3.10543
2.18017
0.00
0.00
0.00
8.90
8.48
4.90
With CHX Day 1 With lesion
Without lesion
Control
15
15
15
0.6537
0.2000
0.1534
1.42656
0.77460
0.59412
0.00
0.00
0.00
4.60
3.00
2.30
Day 3 With lesion
Without lesion
Control
15
15
15
2.5510
0.6738
0.3269
2.32567
1.17535
0.86449
0.00
0.00
0.00
6.30
2.90
2.60

Table 1: Comparison of means & Std. deviation of No. of candidal (CFU)s & efficacy of 0.5% CHX on study & control group samples.

The statistical analysis was done by taking actual values without considering the log values for the No. of candidal (CFU)s count using a Kruskal-Wallis test (H) for group comparison[Table 2], Mann-Whitney U test (z) for inter comparison of groups[Table 3], & Wilcoxon signed rank sum test for comparison between day-1 day-3 samples[Table 4], with statistical package for social science (SPSS) version 11.5 for windows.

Analysis was done by taking actual values: Comparison between group
N Mean Std. Deviation H P-value
Without CHX Day 1 With lesion
Without lesion
Control
15
15
15
15333.3333
333.3333
346.6667
21238.46466
598.41059
1288.33595
14.459 0.001 vhs
Day 3 With lesion
Without lesion
Control
13
13
14
392929230.8
23933892.31
15142.8571
356247813.8
82979013.91
26737.63450
13.593 0.001 vhs
With CHX
Day 1 With lesion
Without lesion
Control
15
15
15
2733.3333
66.6667
13.3333
10311.62081
258.19889
51.63978
1.816
Day 3 With lesion
Without lesion
Control
13
13
14
170846.1538
146.1538
42.8571
550178.10543
296.12887
115.78684
12.566 0.001 vhs

Table 2: Comparison of Means of No. of candidal (CFU)s b/w groups (Kruskal-Wallis Test).

Group Statistics
Groupa N Mean Std. Deviation  Z-value
With lesion Day 1 With0ut CHX
With CHX
15
15
15333.33
2733.3333
21238.46466
10311.62081
2.99600
p=.003 hs
Day 3 With0ut CHX
With CHX
13
13
3.9E+08
170846.2
356247813.8
550178.10543
2.89400
p=.004 hs
Without lesion

Day 1 With0ut CHX
With CHX
15
15
333.3333
66.6667
598.41059
258.19889
1.75300
p=.08 ns
Day 3 With0ut CHX
With CHX
13
13
2.4E+07
146.1538
82979013.91
296.12887
1.79700
p=.072 ns
Control Day 1 With0ut CHX
With CHX
15
15
346.6667
13.3333
1288.33595
51.63978
.63700
p=.524 ns
Day 3 With0ut CHX
With CHX
14
14
15142.86
42.8571
26737.63450
115.78684
1.57100
p=.116 ns

Table 3: Inter -comparison of Means of No. of candidal (CFU)s b/w samples, for with & without CHX. (Mann - Whitney U test).

Paired Samples Test
  Paired Differences  
    Mean Std. Deviation Z-value P-value
Without CHX With lesion
Without lesion
Control
DAY1- DAY3
DAY1- DAY3
DAY1- DAY3
-3.9E+08
-2.4E+07
-14771.4
356238865.3
82978822.26
25813.39630
2.934
2.366
3.023
.003 hs
.018 sig
.043 sig
With CHX With lesion
Without lesion
Control
DAY1- DAY3
DAY1- DAY3
DAY1- DAY3
-167692
-69.2308
-28.5714
539111.62490
235.88350
132.59871
2.666
.921
.816
.008 hs
.357  ns
.414 ns

Table 4: Comparison of Means of No. of candidal (CFU)s b/w Day-1 & Day-3 samples. (Wilcoxon signed rank sum test).

The comparison of Means of No. of candidal (CFU)s b/w groups, the mean and standard deviation (SD) along with probability ‘p’ and ‘H’ values (Where ‘H’ indicates Kruskal- Wallis test) shows that the p-value (p-0.001) was found to be very highly significant for day-1 & day-3 samples from Group-A1, A2 & group-B without 0.5% CHX application, & for day-3 samples from Group-A1, A2 & B after application with 0.5%CHX. The ‘p’ value (p-0.05) was found to be not significant for day-1 samples from group-A1, A2 & B with 0.5%CHX application [Table 2]. The paired intercomparison of means of No. of candidal (CFU)s b/w Day-1 & Day-3 samples shows that the probability p-value (P<0.01) was found to be highly significant for samples with & without 0.5% CHX application in Group-A1 & and the p-value (p<0.05) was found to be significant b/w day-1 & day-3 in Groups-A2 & B for without 0.5% CHX. But p-value (p>0.05) was found to be not significant b/w day-1 & day-3 in Groups- A2 & B for with 0.5% CHX [Table 4]. The paired inter-comparison of Means of No. of candidal (CFU)s b/w samples, for with & without 0.5% CHX application from day1 & day-3 in Group-A1, was found to be highly significant. But the p-value (p<0.05) b/w samples, for with & without 0.5%CHX application from day1 & day-3 in Groups-A2 & B was found to be not significant [Table 3]. The overall comparative analysis of no. of candidal (CFU)s of the samples has been depicted graphically.

Discussion

candidal existence presents a high significance in the etiology of Denture stomatitis. Its incidence has been reported to occur among 11-67% of the Denture wearers.[7,8] The yeasts, being a part of the Denture plaque, adhere and accumulate on the surface of the prosthesis that plays a stocking role for them.[9-11] The ability to form biofilm is intimately associated with the ability to cause infection and as such should be considered an important virulence determinant during Denture stomatitis.[12] The colonization and growth on prostheses by candida species are of clinical importance.[13] Budtz-Jorgenson et al. in his studies on the clinical aspect of candida infection in Denture wearers hypothesized that the candida-induced Denture stomatitis usually does not reflect on any deep-seated systemic abnormality, but the Dentures are primary predisposing factors. Therefore preventive measures must be taken against colonization of candida on palatal mucosa and Dentures.[14] Various drugs have been employed to treat candida-induced Denture stomatitis & CHX is commonly used by dental patients as antiseptics.[6] In the present study an attempt has been made to evaluate the growth of candida species in the Denture biofilms using new sampling technique in vivo,[4] & to test and compare the efficacy of 0.5% CHX as a disinfectant on Denture biofilm in patients with & without Denture stomatitis. Olsen. I did a study on five patients of Denture stomatitis who were treated with a combination of Amphotericin-B lozenges and Denture soaking in 0.2% chlorhexidine to assess their longterm disinfection ability,[7] but Budtz-Jorgenson et al.[14] report Chlorhexidine gluconate (0.2-2%), as a disinfectant for candida infections in Denture wearers. However according to Therand et al.[6] Chlorhexidine at 0.5% was the only fungicidal agent effective on pure cultures, yeast mixtures, and biofilm. So 0.5% CHX was tested for its efficacy on candidal biofilm & was observed for the reduction of fungal load on Denture biofilm before & after 0.5% CHX application over the lesion and nonlesion site of Denture stomatitis patient as well as on normal Denture wearing patients for 1st day & 3rd day. According to Chandra et al. only chlorhexidine (0.5%) reduces a fungal load in biofilm conditions by more than 4 log10 yeast cells per ml & thus fungicidal.[5] In accord with these results, the results of the present study show that the mean No. of candidal (CFU) s without CHX at lesion site on 3rd day was more than 5.7 log10 candidal (CFU)s and the fungal load reduces to 2.5 log10 candidal (CFU)s with an application of 0.5% CHX [Table 1]. Catalan et al.[15] in a study on Denture plaque on palatal mucosa in patients with & without Denture stomatitis revealed that the microbiologic analysis of Denture plaque samples in patients with healthy mucosa showed the presence of gram positive cocci in all & no presence of yeast even in single patient studied. But the samples from Denture stomatitis patient showed the presence of gram positive cocci in all & presence of yeast in all except one patient studied.

In this study, the targeted micro-organisms were only candidal species. In the study group, 1st day samples showed a presence of yeast in all samples except two patients & 3rd day samples showed a presence of yeast in all samples of biofilm retrieved from Denture stomatitis patient. However two patients who didn’t show any presence of yeast on the 1st day did not return on 3rd day & in two patients results were not tabulated because of contamination of disks probably due to technical problems, and in both conditions, these samples were excluded from the study. Though the sample size had been reduced the results were not affected much, as the sample size taken were relatively large with prior considerations of the study subjects & technical factors. In control group, the 1st day samples showed a presence of yeast in only two samples & 3rd day samples showed a presence of yeast in only four sample of biofilm retrieved from non-Denture stomatitis patient. However in control group also one patient who didn’t show any presence of yeast on the 1st day did not return on 3rd day & in two patients results were not tabulated because of contamination of disks probably due to technical problems, and in both conditions, these samples were excluded from the study. The results obtained in this study were relatively similar to the results obtained from Catalan et al. [15] study, except the presence of yeast in two & four biofilm samples of non-Denture stomatitis patients respectively from 1st & 3rd day samples. The presence of yeast in nonDenture stomatitis patients may be due to commensals or may be due to dormant Denture stomatitis without actual lesions. According to Chandra et al.[5] the biofilm associated with candidal cells compared with planktonic form cells are resistant to the antifungal agent used to treat Denture stomatitis & only Chlorhexidine (0.5%) reduces a fungal load in biofilm conditions by more than 4 log 10 yeast cells per ml & thus fungicidal. In the present study the biofilm samples though extracted from sample patients were in their original form, but during subjecting them for growth on SDA-plates & further during efficacy testing with 0.5% CHX, the original form of biofilm could not be maintained & were converted into planktonic form & is considered as one of the limitations of this study not to subject the biofilm for study in its original form instead of planktonic form under the present conditions.

Further investigations should be made to overcome the before mentioned problems associated with a microbiologic study to determine the candidal count in Denture biofilm. However exclusive electron microscopic analysis gives better information regarding biofilm forms but rarely gives quantitative information of candida in a biofilm condition.

Conclusion

Within the limitations of this study, the following conclusions can be drawn:

• The No. of candidal (CFU)s count in Denture-biofilm increases exponentially, with the statistically highly significant order from day-1 to day-3 at lesion site of Denture stomatitis. The No. of candidal (CFU)s count in Denture-biofilm increases exponentially with a statistically significant order from day-1 to day -3 at non-lesion site of patients with and without Denture stomatitis.

• 0.5% CHX was very effective & of statistically highly significant order in reducing the fungal load at lesion site of Denture stomatitis. 0.5% CHX was also effective in reducing the fungal load at non-lesion site of patients with & without Denture stomatitis, but statistically not significant.

As the No. of candidal (CFU)s count in Denture-biofilm decreases significantly, with 0.5% CHX at Denture stomatitis lesion & non-lesion site, & also in nonDenture stomatitis patient, the Dentures can be soaked in 0.5% CHX for a specific time period to treat or to avoid Denture stomatitis in patients wearing Dentures.

Competing Interests

The authors declare that they have no competing interests.

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