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Journal of Clinical and Diagnostic Research. 2014 Jun, Vol-8(6): ZC39-ZC41 3939
DOI: 10.7860/JCDR/2014/9314.4488 Original Article
Decontamination Methods Used for Dental
Burs – A Comparative Study
Keywords: Autoclave, Candida albicans, Diamond burs, Glass bead sterilizer,
Hot air oven, Lactobacilli, Streptococcus mutans, Ultrasonic cleaner
SANGAMESHWAR SAJJANSHETTY1, DEEPA HUGAR 2, SANTOSH HUGAR3, SHASHI RANJAN4, MEGHA KADANI5
INTRODUCTION
Infection control is a major issue in medicine and dentistry because
of concern over communicable diseases transmitted in health care
settings. Both dental personnel and patients are always at risk of
communicating diseases during treatment [1]. It is a century old
observation that disease may spread between patients and staff
and amongst patients through a variety of channels. The use of
effective infection control procedures in the dental office will prevent
cross contamination that may extend to dentist, dental staff, dental
technician and patients [1,2].
Infection control procedure in the office are divided into two major
categories depending on the how the procedure interfere with
development of disease. They either interferes with spread of
disease agent by reducing the contamination or they remove the
disease agent after contamination has occurred [3].
Dental burs are used in clinical dentistry for various procedures
some of which includes caries excavation, access cavity preparation
and crown reduction. During these procedures burs may become
heavily contaminated with necrotic tissue, saliva, blood and potential
pathogens and identified as potential vehicle for cross infection. In
routine dental practice, adequate disinfection and sterilization has
to be focused upon to control cross transmission of infection [4].
The most commonly used methods of sterilization includes soaking
of burs in commercially available disinfectors followed by manual
cleaning or, using ultrasonic bath or, autoclaving [5].
Burs are unique by virtue of their complex architecture which
makes pre-cleaning and subsequent sterilization difficult to achieve.
Inadequate sterilization causes cross infection among the patient
and transmission of disease between the patient and dental
personnel [6,7].
Thus, the present study was conducted to evaluate and compare
the efficiency of commonly available different decontamination
methods for dental burs.
Dentistry Section
METHODOLOGY
The present invivo study was carried out in the Department of
Pedodontics and Preventive Dentistry, Bapuji Dental College and
Hospital Davangere, India. Prior to the conduction of study ethical
approval was done, then informed consent from the parents /
guardians of the pediatric patients was obtained after thoroughly
explaining them about the procedure details and treatment
outcomes. The study is a single blinded study were pediatric
patients were randomly selected from the outpatient department
in the college.
Ninety six round diamond burs (no.18) were selected for the study.
After that these burs were randomly assigned in six groups of 16
each.
Group I: Uncontaminated burs.
Group II: Contaminated burs subjected to manual scrubbing.
Group III: Contaminated burs subjected to hot air oven.
Group IV: Contaminated burs subjected to glass bead sterilization.
Group V: Contaminated burs subjected to ultrasonic cleaner.
Group VI: Contaminated burs subjected to autoclave.
All the experimental group burs were used for the access cavity
preparation in primary teeth. After that burs were removed from
the airotor hand piece with sterile tweezer. These contaminated
burs were carried in transport medium to the Department of Oral
Pathology, and 0.05 ml was taken with the help of inoculating
loop and streaked on Mitis Salivaries agar for selective culturing of
Streptococcus mutans, on Rogosa SL agar for selective culturing
of Lactobacilli and on Sabourauds with chloramphenicol agar for
Candida albicans. These plates were incubated for 48 hrs at 37oC
in a standardized procedure.
Following incubation numbers of Colony Forming Units (CFU’S) of
mutans Streptococci, Lactobacilli and Candida albicans at the end
of two days were counted with colony counting machine.
ABSTRACT
Aims and Objectives: Infection control and modes of sterilizations
are the key factors to avoid cross transmission of infection in the
field of dentistry. Transmission of disease or infection is noted
with improper sterilization of reused instruments. Dental burs
are the most important tool in any endodontic or conservative
procedures of teeth involving tooth contouring, restorative filling
procedures and endodontic procedures. Hence, the present
study is undertaken to assess the efficacy of different methods
of sterilization or decontamination which are routinely used in
dental clinics.
Materials and Methods: For the present study 96 round diamond
burs were selected and divided into 6 groups. These burs were
used for the access cavity preparation to get contamination and
subjected for bacteriological culture. After getting base line date
burs were subjected to manual scrubbing, hot air oven, glass
bead sterilizer, ultrasonic cleaner and autoclave to get post
decontamination data.
Results: The study revealed that mean colony forming units/ml
of Streptococcus mutans decreased maximum for autoclave with
80% reduction, for Lactobacilli 76% reduction and for Candida
albicans maximum reduction seen for glass bead sterilizer with
74%.
Conclusion: Findings of our study revealed that none of the
methods used were found to be absolutely efficacious in the
decontamination of dental burs. However, among the experimental
groups used in the present study, autoclave was found to be the
relatively best method.
Sangameshwar Sajjanshetty et al., Decontamination Methods Used for Dental Burs-A Comparative Study www.jcdr.net
Journal of Clinical and Diagnostic Research. 2014 Jun, Vol-8(6): ZC39-ZC41
4040
STATISTICAL ANALYSIS
Results were expressed as Mean ± Standard deviation (SD), range
values and number of percentages. Kruskal-Wallis ANOVA was used
for multiple group comparisons followed by Wilcoxon’s Rank Sum
test (Mann-Whitney test) for group wise comparisons of reduction
in colony forming units/ml.
RESULTS
Maximum reduction of Streptococcus mutans and Lactobacilli seen
with Autoclave followed by Glass bead, Hot air oven, Ultrasonic,
Manual scrubbing and for 3 glass bead was found to be effective.
When intergroup comparison done for Streptococcus mutans Gr
(Group) II to Gr III, Gr IV, Gr V, Gr VI ; Gr III to Gr VI; Gr IV to Gr VI; Gr
V to Gr VI was found to be statistically significant.
When intergroup comparison done for Lactobacilli Gr II to Gr IV; Gr
II to Gr V; Gr III to Gr IV; Gr III to Gr V; Gr IV to Gr VI ; Gr IV to Gr V
was found to be statistically significant.
When intergroup comparison done for Candida albicans Gr II to Gr
III, Gr IV, Gr V, Gr VI; Gr III to Gr IV, Gr V, Gr VI; Gr IV to Gr V, Gr VI
was found to be p<0.01 and statistically significant [Table/Fig-1-2].
DISCUSSION
Preservation of dental arch and its function is the main motive behind
pediatric dentistry. Retention of the primary teeth is needed until they
are naturally exfoliated. There are several advantages of preserving
the natural primary teeth. Primary teeth help in preserving the arch
length, play an important role in mastication, esthetics, speech and
act as space maintainers for permanent teeth and have psychological
advantage of conserving rather than extracting the tooth [8, 9].
Most of the pathologies of pulp and periapical tissues of teeth
are directly or indirectly related to the microorganisms. Therefore,
to effectively diagnose and treat endodontic infection, one should
have the knowledge of bacteria associated with endodontic
pathology [10].
However, there are few studies concerning root canal microbiota
of primary teeth. Marsh and Largent in one study found that
Streptococci mutans were found 30% to 52% of the cases [11,
12] and Candida albicans were found in 21% of infected root
canals [10, 13].
Currently, numerous articles address the transmission of blood
and tissue borne pathogens from one patient to another via
contaminated devices. Many studies look at the bacterial and viral
contamination of dental and medical instrumentation and the safety
of sterilizing and reusing these instruments. There have also been
concerns over the possible transmission of prions by contaminated
surgical instruments [14].
Some studies have also shown that reuse of instruments is common
and that cleaning of these instruments may not always be effective.
For example Lowe, Burke et al., conducted a survey of general
dentists in Scotland and found that 93% of those who answered the
survey reused matrix bands on multiple patients in their practices.
Although 99% of respondents used a steam autoclave to sterilize
Decontamination methods
Group 1: Control
Sixteen uncontaminated burs were used as control group.
Group 2: Manual Scrubbing
The effectiveness of manual scrubbing was tested using bur brush.
Sixteen contaminated burs were subjected to 40 strokes of bur
brush by holding the bur with a sterile tweezer and brushing from
the shank to the working end. This procedure was done under
running water, after completion of procedure burs were placed in
screw- cap tube containing transport medium amies.
Group 3: Hot Air Oven
Sixteen contaminated burs after cleaning under running tap water
with detergent were kept in a sterile bur stand and placed in hot air
oven for 60 minutes at 160oC. After complete sterilization burs were
recovered and placed in transport medium amies.
Group 4: Glass Bead Sterlizer
Sixteen contaminated burs after cleaning under running tap water
using detergent were submerged in a glass bead sterilizer at a
distance of 2 mm from the wall of the sterilizer for 15 sec at 230oC
with a sterile tweezer. The glass bead sterilizer was controlled by
thermostat and the light indicated the attainment of the required
temperature.
Group 5: Ultrasonic
After cleaning under running tap water with detergent, 16
contaminated burs were placed in ultrasonic cleaner containing
solution which was non ammoniated, non ionic and phosphate free.
After that burs were removed aseptically and placed in transport
medium amies. Effectiveness of ultrasonic bath was confirmed by
aluminum foil test.
Group 6: Autoclave
After cleaning under running tap water with detergent, 16
contaminated burs were cleaned under running tap water and
placed in sterile bur stand and autoclaved for 16 minutes at 121oC
under 16 psi. Sterilization monitoring of autoclave was done with
color changeable chemical tape. After decontamination method,
collected test samples were carried for the microbiological
processing to obtain the specific culture.
[Table/Fig-1]: Showing mean and Standard deviation of the Colony Forming Units/ml of Streptococcus mutans, Lactobacilli and Candida albicans,
before and after decontamination
[Table/Fig-2]: Showing percentage of reduction of microorganism
among experimental group
Before Decontamination After Decontamination
Group Streptococcus
mutans
Lactobacilli Candida albicans Streptococcus
mutans
Lactobacilli Candida albicans
Control 0.5 ± 0.3 0.3 ± 0.2 0.2 ± 0.2
Manual scrubbing 17.9 ± 0.7 11.4 ± 1.1 6.3 ± 0.8 7.0 ± 0.8 5.7 ± 0.5 4.6 ± 1.0
Hot air oven 17.4 ± 1.1 9.8 ± 0.9 6.1 ± 1.0 4.8 ± 0.8 3.4 ± 0.5 1.8 ± 0.5
Glass bead 18.0 ± 0.8 12.1 ± 1.0 6.5 ± 0.7 4.9 ± 0.5 3.3 ± 0.8 1.3 ± 0.5
Ultrasonic 18.2 ± 1.0 12.1 ± 1.1 6.3 ± 0.8 5.5 ± 0.5 4.7 ± 0.5 3.5 ± 0.5
Autoclave 17.9 ± 0.9 8.8 ± 1.2 4.3 ± 0.7 3.7 ± 0.5 2.1 ± 0.4 0.9 ± 0.3
Before Decontamination
Group Streptococcus
mutans
Lactobacilli Candida
albicans
Manual scrubbing 61% 50% 27%
Hot air oven 72% 65% 69%
Glass bead 73% 74% 80%
Ultrasonic 69% 61% 44%
Autoclave 80% 76% 79%
www.jcdr.net Sangameshwar Sajjanshetty et al., Decontamination Methods Used for Dental Burs-A Comparative Study
Journal of Clinical and Diagnostic Research. 2014 Jun, Vol-8(6): ZC39-ZC41 4141
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instruments, they used a variety of pre sterilization cleaning methods,
ranging from a pre-soak only to a combination pre-soak, ultrasonic
cleaning and hand scrubbing [14].
Dental burs are identified as potential vehicle for cross infection
in dental orifice due to their contact with saliva, blood, teeth and
bone [3,6,15]. While most of the dental instruments are effectively
cleaned after use, the diamond bur is often neglected and only
brushed or immersed in a mild disinfectant prior to reuse [16].
Manual scrubbing of dental bur is simple and cheap but it may not
be effective, it also takes time for instruments to be cleaned properly
and it may not be possible in busy practice and also aerosols of
pathogenic microorganisms may be produced by hand cleaning
with contamination of the sink [17,18].
Council on dental materials, instruments and equipments also
stated the dry heat oven is the preferred method for sterilization
of dental burs but produce little rusting or dulling of instruments,
also they are inexpensive to purchase but have substantially longer
processing time than an autoclave [19].
Bead sterilizers have been commonly used for the fast chair side
sterilization of endodontic instruments, because it can easily be placed
in the operatory, burs could be sterilized immediately before, during
and after the surgical procedures but precleaning of instruments is
recommended [3, 20]. It is found that glass bead sterilization is most
effective method of destroying fungal contaminants as and when
compared to autoclave and other groups.
Ultrasonic cleaning has been shown to be effective in removing
dried blood and saliva from the dental instruments and remains
an important system that enhances dental personnel safety during
instrument handeling [21].
Under proper conditions steam under pressure (Autoclave) can
destroy all microorganisms including bacterial spores and it is found
to be relatively the best method to decontaminate dental burs, yet
it has some limitations like it increases the fracture susceptibility,
decreases the cutting efficiency and life span of burs, which all
should be weighed against its benefits.
CONCLUSION
Findings of our study revealed that none of the methods used were
found to be absolutely efficacious in the decontamination of dental
burs. However, among the experimental groups used in the present
study, autoclave was found to be the relatively best method to
decontaminate burs.
Date of Submission: Mar 18, 2014
Date of Peer Review: Apr 17, 2014
Date of Acceptance: May 15, 2014
Date of Online Ahead of Print: May 28, 2014
Date of Publishing: Jun 20, 2014
PARTICULARS OF CONTRIBUTORS:
1. Reader, Department of Pedodontics and Preventive Dentistry, H.K.E.S’s S.N.D.C, Gulbarga, India.
2. Senior Lecturer, Department of Oral and Maxillofacial Pathology, H.K.E.S’s S.N.D.C, Gulbarga, India.
3. Reader, Department of Conservative and Endodontics, Bharatiya Vidyapeetha, Sangli, India.
4. Senior Lecturer, Department of Oral and Maxillofacial Pathology, Buddha Dental College, Patna, India.
5. Postraduate Student, Department of Oral And Maxillofacial Pathology, H.K.E.S’s S.N.D.C, Gulbarga, India.
NAME, ADDRESS, E-MAIL ID OF THE CORRESPONDING AUTHOR:
Dr. Sangameshwar Sajjanshetty,
Plot No 19, Vasant Nagar, M.S.K. Mill Road, Gulbarga-585103, India.
Phone: +919535313292, E-mail: sajjanshettysangamesh@yahoo.com
FINANCIAL OR OTHER COMPETING INTERESTS: None.