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Practical denture disinfection
SECTION
EI~JTOH
Practical Michael
denture L. Brace,
disinfection
DDS,B and Kevin
D. Plummer,
DDSb
Billy Johnson Dental Clinic, Fort Hood, Texas Dental laboratory personel are at risk of contracting infections from dental prostheses that have not been properly disinfected. A 4% chlorhexidine scrub for 15 seconds followed by a 3-minute contact time with a chlorine dioxide solution was effective in disinfecting contaminated dentures. Chair-side disinfection of dental prostheses before laboratory procedures is the key to keeping microbial contamination out of the dental laboratory. (J PROSTHETDENT 1993;70:638-40.)
D ental
prostheses brought into a dental clinic for repair or adjustments are contaminated with bacteria, viruses: and fungi.‘.” Dental laboratory personnel are at risk for contracting infections from dental prostheses that have not been disinfected. In a Veterans Administration cooperative study on hepatitis and dentistry, 22 of 155 (14.2%) dental laboratory technicians tested positive for serological markers for hepatitis B.” The high percentage of positive markers in dental laboratory technicians is above the 4 % rate for hepatitis B serological markers found in 1600 geographically diverse volunteer blood donors.’ This could be considered as an indicator of the greater risk faced by dental technicians in occupational exposure to bloodborne pathogens. To prevent microbiologic contamination of the dental laboratory, dental prostheses must be disinfected before any laboratory procedures are started. Disinfecting contaminated dental prostheses before they enter the laboratory is known as the “Barrier System.“” Barrier protection is a key part ot’ any efl’ect.ive infection control and the Occupational Safety and Health Administration (OSHA) exposure control program.; This system allows the dental laboratory to operate as a clean area. Various methods of chemically disinfecting dental prostheses have been evaluated. They include 5.25% sodium hypochlorite, chlorine dioxide, 2 7~ glutaraldehyde, and tetravalent oxident.6T”.” To ensure proper disinfection, simple methods with adequate contact time for the disinfectant. must be used. This study demonstrated that dental prostheses could be easily and effectively disinfected with a chlorine dioxide procedure. The opinions contained herein are those of the authors and are not IO be construed as those of the lJ.S. Army or the Department of !kfense “Maior, L’S Army, DC: Senior Resident, Advanced Educational Program in General Dent,istry. “Lieutenant. Colonel. I;.S. Army, DC; Assistant Director, Advanced Educational Program in General Dentistry.
10/1/502Q2
MATERIAL
AND
METHODS
Twenty-two complete and removable partial dentures taken directly from patients’ mouths were used for microbiologic analysis. The first phase of the study cultured 11 dentures for contamination. All prostheses and equipment were handled in an aseptic manner during the test. The denture was taken from the patient’s mouth and placed directly in a sterile nylon autoclave bag containing 100 cc of sterile normal saline. The bag was agitated by hand for 1 minute and then allowed to stand for 9 minutes. A sterile, disposable 0.001 ml inoculating loop was used to obtain a sample of the solution. The sample was spread onto a 5 % sheep blood agar culture plate. The denture was placed in a container of chlorine dioxide disinfection solution (Alcide LD, Alcide Corp., Norwalk, Conn.) for the 3-minute contact time recommended by the manufacturer. The denture was rinsed with sterile normal saline to remove residual disinfectant and placed in another sterile nylon autoclave bag containing 100 cc of sterile normal saline. The bag was agitated for 1 minute and then allowed to stand for 9 minutes. A 0.001 ml sample of this solution was spread onto a 5 7% sheep blood agar plate. The 5% sheep blood agar culture plates were incubated for 48 hours. The control denture was treated in the same manner as all the other dentures except that it was not disinfected. The results were read by a microbiologist. In the second phase of this study, cultures from 11 complete and partial dentures were examined for contamination. The denture was placed directly into 100 cc of sterile normal saline solution in a sterile nylon autoclave bag. The solution was agitated for 1 minute and allowed to sit for 9 minutes. A 0.001 ml sample of the solution was streaked onto a 5 % sheep blood agar culture plate. The denture was scrubbed for 15 seconds with a toothbrush and 4% chlorhexidine skin cleanser (Hibiclens, Stuart Pharmaceutical, Wilmington, Del.) to remove debris. The denture was then sprayed according to manufacturer’s instructions on all surfaces with a solution of chlorine dioxide (Alcide LD, Altide Corp.). After 3 minutes the denture was rinsed with
VOLUME
70
NUMBER
6
BRACE
AND
Table
I.
THE
PLUMMER
Colony
count by specimen
after disinfection
Specimen Type
No.
Complete Complete Complete Removable partial Complete Complete Complete Complete Removable partial Complete Complete
1
2 3 4 5 6 7 8 9 10 11
*Chlorine dioxide disinfection solution tEach colony = 1000 organisms.
Table
Colony
II.
count
Specimen No.
*Scrubbed
15 seconds
with
after disinfection
> 100,000 > 100,000 95,000 40,000 >100,000 > 100,000 100,000 >100,000 36,000 100,000 >100,000
Disinfection method*
denture
4% chlorohexidine,
sprayed
Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub None with
chlorine
Colony count disinfection?
Colony count disinfection*
after
No growth No growth No growth No growth No growth No growth No growth No growth No growth No growth >100,000
dioxide
Microbiologic testing for each agar plate is listed in Tables I and II. All dentures had positive cultures before they were disinfected. All disinfected dentures tested had negative cultures. There was positive growth on ail cultures from the control dentures.
DISCUSSION The results of this study demonstrate that dentures taken directly from a patient’s mouth are heavily contaminated with microorganisms. The method for culturing
before
>100,000 80,000 90,000 >100,000 80,000 >100,000 90,000 90,000 80,000 >100,000 > 100,000
and spray and spray and spray and spray and spray and spray and spray and spray and spray and spray (control)
RESULTS
1993
before
by scrub and spray
sterile normal saline to remove any excess disinfectant and placed in 100 cc of sterile normal saline in a sterile nylon autoclave bag. The bag was agitated for 1 minute and allowed to stand for 9 minutes. A 0.001 ml sample of this solution was streaked onto a 5 % sheep blood agar plate. All of the cultures were incubated for 48 hours. The control denture was treated in the same manner as all of the other dentures, but was not scrubbed or disinfected.
DECEMBER
Colony count disinfection?
Soak Soak Soak Soak Soak Soak Soak Soak Soak Soak None (control)
Complete Complete Complete Complete Removable partial Complete Complete Complete Removable partial Complete Complete
1
2 3 4 5 6 7 8 9 10 11
DENTISTRY
for 3 minutes.
by specimen Type
OF PROSTHETIC
by immersion
Disinfection method*
denture
JOURNAL
solution.
and allowed
Colony count disinfection*
after
No growth No growth No growth No growth No growth No growth No growth No growth No growth No growth >100,000
to sit for 3 minutes.
these samples is the same method that is used in culturing urine samples. It is capable of giving a semiquantitative measurement of the microorganisms present on a denture before and after disinfecti0n.l’ This procedure allows all surfaces of a denture to be sampled because the saline will wash over the entire denture. Disinfection with Alcide LD chlorine dioxide is effective in reducing the number of microorganisms on a denture. Although immersing the denture in chlorine dioxide without a prior scrub was effective in the 10 samples tested, immersion without a scrub is not recommended. If the denture is heavily contaminated it probably would not be completely disinfected by immersion only. The E-second scrub with 4% chlorhexidine skin cleanser followed by 3 minutes of contact time with sprayed chlorine dioxide is as effective in reducing microorganisms as the soaking method. This is a realistic and practical approach for denture disinfection. By ensuring that all dental prostheses are disinfected before they enter the dental laboratory, the dental laboratory will remain clean. This will help in preventing
539
THE
JOURNAL
OF PROSTHETIC
BRACE
DENTISTRY
infection of dentaI technicians and cross contamination of other patients.
Historically infection control procedures for the dental laboratory have been ignored because they are cumbersome, time-consuming, and perceived to be an inconvenience instead of a neeessity. The first step in maintaining a clean dental laboratory is to allow only properly disinfected items into the dental laboratory. This includes all prostheses and impressions. Performing this disinfection at chair side is the key to keeping microbiologic contamination out of the dental laboratory. The method using a I5-second scrub with 4 % chlorhexidine followed by 3 minutes of contact time with properly applied Alcide LD chlorine dioxide demonstrates that a simple and time-efficient method for dental prosthesis disinfection can be effective.
REFERENCES 1. Powell GL, Runnelis RD, Saxon BA, Whisenant BK. The presence and identification of organisms transmitted to dental laboratories. J PROS‘I’HET DE:NT 1990;64:235-7.
AND
PLUMMER
2. Schwartz RS, Kinyon TJ, Mayhew R. Infection control in the dental laboratory: a review of the literature. Military Medicine 1991;156:1-4. 3. Wakefield CW. Laboratory contamination of dental prostheses. J PROSTHET DENT 1980;44:143-6. 4. Schiff ER, de Medina MD, Kline SN, et al. Veterans Administration cooperative study on hepatitis and dentistry. J Am Dent Assoc 1986;113:390-6. 5. Dodd RY, Nath N, Pielech M, O’Neil S, Sherman KE. Prevalence of infection of four heterotropic viruses in a voluntary donor population. Transfusion 1982;22:422. 6. Henderson, CW, Schwartz RS, Herbold ET, Mayhew RB. Evaluation of the barrier system, an infection control system for the dental laboratory. J PROSTHET DENT 1987;58:517-21. 7. Rules and Regulations. Title 29, Code of Federal Regulations, Section 1910.1030 Bloodborne Pathogens. Federal Register. ~0156, No. 235, Dee 6, 1991. 8. Rudd RW, Senia ES, McCleskey FK, Adams ED. Sterilization of complete dentures with sodium hypochlorite. J PROSTHET DENT 1984; 51: 318-21. 9. Kinyon TJ, Schwartz RS, Burgess JO, Bradley DV. The use of warm solutions for rapid disinfection of prostheses. Int J Prosthodont 1989;2:518-23. 10. Koneman EW, Allen SD, Janda WM, Schreckenberger PC, Washington CW. Color atlas and textbook of diagnostic microbiology. 4th ed. Philadelphia: JB Lippencott, 1992:28-33.
Reprint
requests
to:
DR. KEVIN D. PLUMMER 4163 HOUNDS CT. EVANS, GA 30809
VOLUME
70
NUMBER
6
EI~JTOH
Practical Michael
denture L. Brace,
disinfection
DDS,B and Kevin
D. Plummer,
DDSb
Billy Johnson Dental Clinic, Fort Hood, Texas Dental laboratory personel are at risk of contracting infections from dental prostheses that have not been properly disinfected. A 4% chlorhexidine scrub for 15 seconds followed by a 3-minute contact time with a chlorine dioxide solution was effective in disinfecting contaminated dentures. Chair-side disinfection of dental prostheses before laboratory procedures is the key to keeping microbial contamination out of the dental laboratory. (J PROSTHETDENT 1993;70:638-40.)
D ental
prostheses brought into a dental clinic for repair or adjustments are contaminated with bacteria, viruses: and fungi.‘.” Dental laboratory personnel are at risk for contracting infections from dental prostheses that have not been disinfected. In a Veterans Administration cooperative study on hepatitis and dentistry, 22 of 155 (14.2%) dental laboratory technicians tested positive for serological markers for hepatitis B.” The high percentage of positive markers in dental laboratory technicians is above the 4 % rate for hepatitis B serological markers found in 1600 geographically diverse volunteer blood donors.’ This could be considered as an indicator of the greater risk faced by dental technicians in occupational exposure to bloodborne pathogens. To prevent microbiologic contamination of the dental laboratory, dental prostheses must be disinfected before any laboratory procedures are started. Disinfecting contaminated dental prostheses before they enter the laboratory is known as the “Barrier System.“” Barrier protection is a key part ot’ any efl’ect.ive infection control and the Occupational Safety and Health Administration (OSHA) exposure control program.; This system allows the dental laboratory to operate as a clean area. Various methods of chemically disinfecting dental prostheses have been evaluated. They include 5.25% sodium hypochlorite, chlorine dioxide, 2 7~ glutaraldehyde, and tetravalent oxident.6T”.” To ensure proper disinfection, simple methods with adequate contact time for the disinfectant. must be used. This study demonstrated that dental prostheses could be easily and effectively disinfected with a chlorine dioxide procedure. The opinions contained herein are those of the authors and are not IO be construed as those of the lJ.S. Army or the Department of !kfense “Maior, L’S Army, DC: Senior Resident, Advanced Educational Program in General Dent,istry. “Lieutenant. Colonel. I;.S. Army, DC; Assistant Director, Advanced Educational Program in General Dentistry.
10/1/502Q2
MATERIAL
AND
METHODS
Twenty-two complete and removable partial dentures taken directly from patients’ mouths were used for microbiologic analysis. The first phase of the study cultured 11 dentures for contamination. All prostheses and equipment were handled in an aseptic manner during the test. The denture was taken from the patient’s mouth and placed directly in a sterile nylon autoclave bag containing 100 cc of sterile normal saline. The bag was agitated by hand for 1 minute and then allowed to stand for 9 minutes. A sterile, disposable 0.001 ml inoculating loop was used to obtain a sample of the solution. The sample was spread onto a 5 % sheep blood agar culture plate. The denture was placed in a container of chlorine dioxide disinfection solution (Alcide LD, Alcide Corp., Norwalk, Conn.) for the 3-minute contact time recommended by the manufacturer. The denture was rinsed with sterile normal saline to remove residual disinfectant and placed in another sterile nylon autoclave bag containing 100 cc of sterile normal saline. The bag was agitated for 1 minute and then allowed to stand for 9 minutes. A 0.001 ml sample of this solution was spread onto a 5 7% sheep blood agar plate. The 5% sheep blood agar culture plates were incubated for 48 hours. The control denture was treated in the same manner as all the other dentures except that it was not disinfected. The results were read by a microbiologist. In the second phase of this study, cultures from 11 complete and partial dentures were examined for contamination. The denture was placed directly into 100 cc of sterile normal saline solution in a sterile nylon autoclave bag. The solution was agitated for 1 minute and allowed to sit for 9 minutes. A 0.001 ml sample of the solution was streaked onto a 5 % sheep blood agar culture plate. The denture was scrubbed for 15 seconds with a toothbrush and 4% chlorhexidine skin cleanser (Hibiclens, Stuart Pharmaceutical, Wilmington, Del.) to remove debris. The denture was then sprayed according to manufacturer’s instructions on all surfaces with a solution of chlorine dioxide (Alcide LD, Altide Corp.). After 3 minutes the denture was rinsed with
VOLUME
70
NUMBER
6
BRACE
AND
Table
I.
THE
PLUMMER
Colony
count by specimen
after disinfection
Specimen Type
No.
Complete Complete Complete Removable partial Complete Complete Complete Complete Removable partial Complete Complete
1
2 3 4 5 6 7 8 9 10 11
*Chlorine dioxide disinfection solution tEach colony = 1000 organisms.
Table
Colony
II.
count
Specimen No.
*Scrubbed
15 seconds
with
after disinfection
> 100,000 > 100,000 95,000 40,000 >100,000 > 100,000 100,000 >100,000 36,000 100,000 >100,000
Disinfection method*
denture
4% chlorohexidine,
sprayed
Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub None with
chlorine
Colony count disinfection?
Colony count disinfection*
after
No growth No growth No growth No growth No growth No growth No growth No growth No growth No growth >100,000
dioxide
Microbiologic testing for each agar plate is listed in Tables I and II. All dentures had positive cultures before they were disinfected. All disinfected dentures tested had negative cultures. There was positive growth on ail cultures from the control dentures.
DISCUSSION The results of this study demonstrate that dentures taken directly from a patient’s mouth are heavily contaminated with microorganisms. The method for culturing
before
>100,000 80,000 90,000 >100,000 80,000 >100,000 90,000 90,000 80,000 >100,000 > 100,000
and spray and spray and spray and spray and spray and spray and spray and spray and spray and spray (control)
RESULTS
1993
before
by scrub and spray
sterile normal saline to remove any excess disinfectant and placed in 100 cc of sterile normal saline in a sterile nylon autoclave bag. The bag was agitated for 1 minute and allowed to stand for 9 minutes. A 0.001 ml sample of this solution was streaked onto a 5 % sheep blood agar plate. All of the cultures were incubated for 48 hours. The control denture was treated in the same manner as all of the other dentures, but was not scrubbed or disinfected.
DECEMBER
Colony count disinfection?
Soak Soak Soak Soak Soak Soak Soak Soak Soak Soak None (control)
Complete Complete Complete Complete Removable partial Complete Complete Complete Removable partial Complete Complete
1
2 3 4 5 6 7 8 9 10 11
DENTISTRY
for 3 minutes.
by specimen Type
OF PROSTHETIC
by immersion
Disinfection method*
denture
JOURNAL
solution.
and allowed
Colony count disinfection*
after
No growth No growth No growth No growth No growth No growth No growth No growth No growth No growth >100,000
to sit for 3 minutes.
these samples is the same method that is used in culturing urine samples. It is capable of giving a semiquantitative measurement of the microorganisms present on a denture before and after disinfecti0n.l’ This procedure allows all surfaces of a denture to be sampled because the saline will wash over the entire denture. Disinfection with Alcide LD chlorine dioxide is effective in reducing the number of microorganisms on a denture. Although immersing the denture in chlorine dioxide without a prior scrub was effective in the 10 samples tested, immersion without a scrub is not recommended. If the denture is heavily contaminated it probably would not be completely disinfected by immersion only. The E-second scrub with 4% chlorhexidine skin cleanser followed by 3 minutes of contact time with sprayed chlorine dioxide is as effective in reducing microorganisms as the soaking method. This is a realistic and practical approach for denture disinfection. By ensuring that all dental prostheses are disinfected before they enter the dental laboratory, the dental laboratory will remain clean. This will help in preventing
539
THE
JOURNAL
OF PROSTHETIC
BRACE
DENTISTRY
infection of dentaI technicians and cross contamination of other patients.
Historically infection control procedures for the dental laboratory have been ignored because they are cumbersome, time-consuming, and perceived to be an inconvenience instead of a neeessity. The first step in maintaining a clean dental laboratory is to allow only properly disinfected items into the dental laboratory. This includes all prostheses and impressions. Performing this disinfection at chair side is the key to keeping microbiologic contamination out of the dental laboratory. The method using a I5-second scrub with 4 % chlorhexidine followed by 3 minutes of contact time with properly applied Alcide LD chlorine dioxide demonstrates that a simple and time-efficient method for dental prosthesis disinfection can be effective.
REFERENCES 1. Powell GL, Runnelis RD, Saxon BA, Whisenant BK. The presence and identification of organisms transmitted to dental laboratories. J PROS‘I’HET DE:NT 1990;64:235-7.
AND
PLUMMER
2. Schwartz RS, Kinyon TJ, Mayhew R. Infection control in the dental laboratory: a review of the literature. Military Medicine 1991;156:1-4. 3. Wakefield CW. Laboratory contamination of dental prostheses. J PROSTHET DENT 1980;44:143-6. 4. Schiff ER, de Medina MD, Kline SN, et al. Veterans Administration cooperative study on hepatitis and dentistry. J Am Dent Assoc 1986;113:390-6. 5. Dodd RY, Nath N, Pielech M, O’Neil S, Sherman KE. Prevalence of infection of four heterotropic viruses in a voluntary donor population. Transfusion 1982;22:422. 6. Henderson, CW, Schwartz RS, Herbold ET, Mayhew RB. Evaluation of the barrier system, an infection control system for the dental laboratory. J PROSTHET DENT 1987;58:517-21. 7. Rules and Regulations. Title 29, Code of Federal Regulations, Section 1910.1030 Bloodborne Pathogens. Federal Register. ~0156, No. 235, Dee 6, 1991. 8. Rudd RW, Senia ES, McCleskey FK, Adams ED. Sterilization of complete dentures with sodium hypochlorite. J PROSTHET DENT 1984; 51: 318-21. 9. Kinyon TJ, Schwartz RS, Burgess JO, Bradley DV. The use of warm solutions for rapid disinfection of prostheses. Int J Prosthodont 1989;2:518-23. 10. Koneman EW, Allen SD, Janda WM, Schreckenberger PC, Washington CW. Color atlas and textbook of diagnostic microbiology. 4th ed. Philadelphia: JB Lippencott, 1992:28-33.
Reprint
requests
to:
DR. KEVIN D. PLUMMER 4163 HOUNDS CT. EVANS, GA 30809
VOLUME
70
NUMBER
6