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 Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 9  |  Issue : 1  |  Page : 32-35

Bacteria colonizing acrylic resin complete dentures, after long-term use and the 1st week of new dentures placement


Faculty of Dentistry, Al Azhar University, Gaza, Palestine

Date of Web Publication11-Oct-2019

Correspondence Address:
Dr. Waseem Mushtaha
Faculty of Dentistry, Al Azhar University, Gaza
Palestine
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijmd.ijmd_26_19

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  Abstract 


Purpose: The study aims to identify the bacteria present in acrylic complete dentures after long-term use and after the 1st week of placing a new denture.
Subjects and Methods: A total of seven subjects presented to the Department of Removable Prosthodontics Clinic, Al Azhar University, Gaza, Palestine, who had old and new complete dentures took part in this study. The inner and outer surfaces of the complete denture bases of both upper and lower dentures were sampled, the samples were cultured, and the bacterial type was determined by microbiological methods.
Results: Of the seven subjects studied, five subjects have shown Staphylococcus (STAPH) spp. in the inner and outer surfaces of both upper and lower dentures for the old and the new as well, while one subject has shown the STAPH spp. also on the lower surfaces of both old and new denture, but the upper surfaces showed no bacterial growth. The last subject had grown bacteria on both upper and lower old dentures, but in the new denture, the bacteria grew only in the upper surface.
Conclusion: STAPH spp. showed a great prevalence in both old and 1 week of dentures in use as it predominated in the inner tissue surfaces as well as the outer polished surfaces.

Keywords: Bacterial colonization; complete denture; polished surface; staphylococci; tissue surface


How to cite this article:
Mushtaha W. Bacteria colonizing acrylic resin complete dentures, after long-term use and the 1st week of new dentures placement. Indian J Multidiscip Dent 2019;9:32-5

How to cite this URL:
Mushtaha W. Bacteria colonizing acrylic resin complete dentures, after long-term use and the 1st week of new dentures placement. Indian J Multidiscip Dent [serial online] 2019 [cited 2019 Dec 10];9:32-5. Available from: http://www.ijmdent.com/text.asp?2019/9/1/32/268990




  Introduction Top


A complete denture is a removable acrylic prosthetic device which replaces all teeth and bone loss in an entire dental arch providing a level of esthetics and function, consisting mainly of two parts, the artificial teeth and the denture base which is carrying them.[1] Complete dentures have three surfaces – the fitting surface which is the internal surface that is relying on oral tissue, the occlusal surface between artificial teeth, and the polished surface which is the external smooth surface of the appliance. As the oral cavity is a gate between the external environment and internal environment of our bodies, so many species of microorganisms settle in the different surfaces of the oral cavity and related tissues[2] as well as the surface of acrylic resin prostheses.[3],[4] Thus, the aim of this study is to identify bacteria inhabiting various surfaces of the acrylic complete denture bases after a long period of placement and after short one using cultures and biochemical tests.


  Subjects and Methods Top


Seven subjects using acrylic resin complete dentures presented to the Department of Removable Prosthodontics Clinic, Al Azhar University, Gaza, Palestine, took part in this study. Healthy patients with healthy oral mucosa were approved after clinical examination, and none of them had any medications especially antibiotics for 3 months or used detergents or NaOCl[5] to clean the dentures before the study. The objective of this study was explained to the patients, and consent was obtained from all of them. The study was authorized by the head of the Faculty of Dentistry, Al Azhar University, Gaza, Palestine. The seventh subject visits the prosthodontics clinic to obtain new complete dentures upon their request, while the old dentures are still in use [Table 1]. [Table 2] illustrates different sites of samples taken from the selected patients.
Table 1: Study subjects characteristics

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Table 2: Sampling for microbiological investigation

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Acrylic dentures were rinsed with water only, and the patients were instructed neither to eat before swabbing nor to use cleansing agents.[5],[6],[7],[8] Sterile cotton swabs were used to collect samples from four different sites of the complete denture, which are the upper polished, tissue surfaces and the lower polished and tissue surfaces applied on the old dentures in use, and this procedure was repeated on the new dentures after 1 week of placement.

Samples were packed in sterile pouches and transported to the microbiology laboratory and were cultured within 1 h of sample collection. Cultivation was done using blood agar and MacConkey agar plates and was kept at a sterile environment at 37°C for 72 h. The colonies were described according to the size, shape, color, and ability to grow in the blood and/or MacConkey agar. Gram reaction was determined along with specific traits that helped to some extent to distinguish which type of bacteria inhabits dentures. For accurate identification of the microorganism, series of biochemical tests were performed such as catalase test and coagulase test.

Bacteria growing on the blood agar only were considered to be Gram-positive bacteria, while bacteria growing in both blood and MacConkey agar are Gram-negative ones. The presence of bubbles on the slide after adding the test microorganism to a drop of 3% hydrogen peroxide was interpreted as catalase test positive. Catalase test is used to differentiate Gram-positive cocci into staphylococci (+) and streptococci (−). Coagulase test was interpreted as positive if a clot was formed after 24 h of incubating the test organism in 0.5 ml plasma. Staphylococcus aureus is coagulase-positive while other staphylococci are coagulase-negative.


  Results Top


All samples have shown more than 100,000 colonies to be counted on the plates.

Statistical analysis

Data were scheduled and descriptive statistics were formulated to clarify the bacterial distribution on the different surfaces of the denture and test the relation between the denture type (old/new), denture surface (polished/tissue), and the patient sex. Around 50 samples out of 56 have shown Staphylococcus (STAPH) spp. as Gram-positive bacteria, appear spherical (cocci), and form in grape-like clusters having white or cream color, and this is obtained in both old and new dentures' samples.

[Table 3] and [Figure 1] show that there are seven subjects. Laboratory results have shown that five out of seven marked the growth of STAPH-type bacteria on the upper and lower surface of the old and new denture, while one of them showed the growth of bacteria on the lower surface of both old and new denture, but the upper surface showed no bacterial growth. The results also showed that the last subject had grown bacteria on both upper and lower old denture, but in the new denture, the bacteria grew only in the upper denture and did not grow in the lower. From this and according to the obtained laboratory results, it is obvious that STAPH-type bacteria grow on the denture, regardless whether they are old or new and regardless of the type of surface, and the lack of growth of bacteria on some surfaces in a few individuals was by accident or for some other reasons related to the laboratory environment.
Table 3: Bacterial growth at different surfaces of complete dentures according to the patients

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Figure 1: Percentage of positive samples according to site of collection

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As [Table 4] and [Figure 2] show, the percentage of the male in the sample was 86% while the female was 14%, with a sex ratio reaching 6. As for bacterial growth, the findings showed that the upper surface in the male sample demonstrates 83.3% positive (Pos.) and 16.7% negative (Neg.), while in the lower surface, the bacterial growth was 100% Pos. With respect to the female, [Figure 2] shows that the percentage of bacterial growth in the upper surface was 100% Pos. while in the lower surface was 50% Pos. and 50% Neg. The total sample findings showed that the bacterial growth in the upper surface was 14.3% Neg. and 85.7% Pos. while in the lower surface was 7.1% Neg. and 92.9% Pos.
Table 4: Relative distribution of bacteria in the whole sample according to the type of surface, sex, and sex ratio

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Figure 2: The percentage of bacterial growth in the oral surface

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From [Table 5] and [Figure 3], we found that 100% of old lower dentures have STAPH bacteria in both polishing and roughing surface, but 86% of new lower dentures have this type of bacteria in both polishing and roughing surface, while we found that 86% of old and new lower dentures have STAPH bacteria in both polishing and roughing surface.
Table 5: Relative distribution of the presence and growth of bacteria in the sample according to type of denture (old/new) and the surface

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Figure 3: Distribution of the presence and growth of bacteria in the sample

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  Discussion Top


From the results of this study, it is obvious that acrylic complete dentures harbor STAPH species and these results mark that various surfaces of the complete dentures were favorable environments for bacterial survival whether being fitting or polished surfaces and this is obtained in dentures after long-term use and short-term use as well.

Bacteria growing on the blood agar only were considered to be Gram-positive bacteria while bacteria growing in both blood and MacConkey agar are Gram-negative ones.

The presence of bubbles on the slide after adding the test microorganism to a drop of 3% hydrogen peroxide was interpreted as catalase test positive. Catalase test is used to differentiate Gram-positive cocci into staphylococci (+) and streptococci (−).

In 50 plates, there were clusters of white cocci that grew only in the blood agar and showed turbidity with catalase test which emphasized the presence of staphylococci in both polished and tissue surfaces of old and new dentures. Thus, complete dentures serving a shelter for bacteria as presented from the findings of this study and relying on previous studies.[4],[7],[8],[9],[10],[11] Concerning that oral and nasal regions are rich sources of microorganisms, staphylococci showed a prevalence due to proximity to the pharyngeal region, especially in the elderly edentulous patients who used to wear complete dentures,[10],[11] even though complete dentures effect on oral flora are still limited and the influence needs to be studied regarding several factors.[9]

On the one hand, several studies discussed the probability of bacteria being settled in the denture after a cross-contamination in dental laboratories during the process of manufacturing the complete dentures, [12,13] especially through the procedure of polishing,[14] which is considered a possible source of transmission of infections in the laboratory and requires improved techniques for infection control.[15]

On the other hand, the surfaces that showed no STAPH spp. growth and marked as negative may be attributed to a minor, occasional error during transfer, or may be due to inaccuracy in controlling the laboratory environment, or even this happened by chance that is without known, apparent, or deliberate cause.


  Conclusion Top


Whether old or new denture, both polished and tissue surfaces of acrylic complete dentures act as a staphylococci attachment sites (biofilms). This type of bacteria is enhanced mainly by the old age and complete dentures use and predominates in the pharyngeal region, or it may be transmitted to dentures as contaminants during fabrication in the laboratory. All these factors play an important role in the pervasiveness of STAPHspp. in the various surfaces and internal areas of the complete denture.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Zhao J, Wang X. Complete dentures. Dental prostheses. In: Advanced Ceramics for Dentistry. 1st ed., Ch. 3. Waltham, MA, USA: Butterworth-Heinemann; 2014. p. 23-49.  Back to cited text no. 1
    
2.
Moore WE, Moore LV. The bacteria of periodontal diseases. Periodontol 2000 1994;5:66-77.  Back to cited text no. 2
    
3.
Sumi Y, Kagami H, Ohtsuka Y, Kakinoki Y, Haruguchi Y, Miyamoto H, et al. High correlation between the bacterial species in denture plaque and pharyngeal microflora. Gerodontology 2003;20:84-7.  Back to cited text no. 3
    
4.
Glass RT. Infection of dental implements and appliances, part 2: The denture. Dent Today 2004;23:116, 118, 120-3.  Back to cited text no. 4
    
5.
Felipucci DN, Davi LR, Paranhos HF, Bezzon OL, Silva RF, Barbosa Junior F, et al. Effect of different cleansers on the weight and ion release of removable partial denture: An in vitro study. J Appl Oral Sci 2011;19:483-7.  Back to cited text no. 5
    
6.
Smith AJ, Jackson MS, Bagg J. The ecology of staphylococcus species in the oral cavity. J Med Microbiol 2001;50:940-6.  Back to cited text no. 6
    
7.
Glass RT, Conrad RS, Bullard JW, Goodson LB, Mehta N, Lech SJ, Loewy ZG. Evaluation of microbial flora found in previously worn prostheses from the Northeast and Southwest regions of the United States. J Prosthet Dent 2010;103:384-9.  Back to cited text no. 7
    
8.
Glass RT, Conrad RS, Bullard JW, Goodson LB, Mehta N, Lech SJ, et al. Evaluation of cleansing methods for previously worn prostheses. Compend Contin Educ Dent 2011;32:68-73.  Back to cited text no. 8
    
9.
Yu WQ, Tian F, Guo XK, Zhang FQ, Ye DX. Changes of oral bacteria flora after wearing complete denture. Shanghai Kou Qiang Yi Xue 2018;27:56-60.  Back to cited text no. 9
    
10.
Sousa C, Teixeira P, Oliveira R. Influence of surface properties on the adhesion of Staphylococcus epidermidis to acrylic and silicone. Int J Biomater 2009;2009:718017.  Back to cited text no. 10
    
11.
Sharma A, Shrestha B, Parajuli PK, Suwal P, Singh RK. A comparative study of microorganisms adhered to different surfaces of complete dentures. EC Dent Sci 2016;6:1368-75.  Back to cited text no. 11
    
12.
Wakefield CW. Laboratory contamination of dental prostheses. J Prosthet Dent 1980;44:143-6.  Back to cited text no. 12
    
13.
Jagger DC, Huggett R, Harrison A. Cross-infection control in dental laboratories. Br Dent J 1995;179:93-6.  Back to cited text no. 13
    
14.
Agostinho AM, Miyoshi PR, Gnoatto N, Paranhos Hde F, Figueiredo LC, Salvador SL. Cross-contamination in the dental laboratory through the polishing procedure of complete dentures. Braz Dent J 2004;15:138-43.  Back to cited text no. 14
    
15.
Kugel G, Perry RD, Ferrari M, Lalicata P. Disinfection and communication practices: A survey of U.S. dental laboratories. J Am Dent Assoc 2000;131:786-92.  Back to cited text no. 15
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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  In this article
Abstract
Introduction
Subjects and Methods
Results
Discussion
Conclusion
References
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