This document provides an overview of sterilization and infection control. It begins with definitions of key terms like sterilization, disinfection, and antisepsis. It then covers various physical and chemical sterilization methods like dry heat, moist heat/autoclaving, filtration, radiation, and chemical agents. Biological controls for different sterilization methods are discussed. The relevance for prosthodontics is explained, including sterilizing instruments, impressions, and elastomeric materials. Studies on the effects of chemical disinfection on dimensional changes in impression materials are summarized. Occupational infections and conclusions are also mentioned.

1. STERILIZATION
AND INFECTION
CONTROL
PRESENTED BY :
DR. KELLY NORTON
FIRST YEAR POST GRADUATE STUDENT
DEPARTMENT OF PROSTHODONTICS
GUIDED BY :
DR. ARCHANA SHETTY
167

2. CONTENTS
 Introduction
 Terminologies
 Classification of agents
 Details of individual agents
 Biological Controls
 Relevance of sterilization in Prosthodontics
 Introduction to infection and infection control
 Occupationally acquired infections
 Conclusion
 References
 Cross references
2
67

3. DEFINITIONS
 STERILIZATION - The process by which an article, surface or medium is
freed of all living micro-organisms either in vegetative or spore state.
 DISINFECTION- The destruction or removal of all pathogenic
organisms, or organisms capable of giving rise to infection.
 ANTISEPSIS- The prevention of infection, usually by inhibiting the
growth of bacteria in wounds or tissues.
367

4. DEFINITIONS
 BACTERICIDAL AGENTS: Those which are able to kill bacteria.
 BACTERIOSTATIC AGENTS: Only prevents the multiplication of bacteria
which may however remain alive.
 DECONTAMINATION: The process of rendering an article or area free of
danger from contaminants, including microbial, chemical, radioactive
and other hazards.
467

5. METHODS OF STERILIZATION AND DISINFECTION
PHYSICAL METHODS
• SUNLIGHT
• DRYING
• DRY HEAT
• MOIST HEAT
• FILTRATION
• RADIATION
• ULTRASONIC AND SONIC
VIBRATIONS
CHEMICAL METHODS
• ALCOHOLS
• ALDEHYDES
• DYES
• HALOGENS
• PHENOLS
• SURFACE-ACTIVE AGENTS
• METALLIC SALTS
• GASES
567

6.  Sunlight:- Active germicidal effect due to the combined effect of U.V and
heat rays. e.g.:- river, tanks & lakes.
 Drying:- 4/5ths of weight of bacterial cell consist of water and hence drying
has a deleterious effect on many bacteria.
6
 Flaming:- Inoculating loops or wires, the tip of forceps &
needles and spatulas are held in a bunsen flame till they become
red hot in order to be sterilized.
 Incineration :- Rapidly destroying materials such as soiled
dressings, bedding, animal carcasses, pathological materials etc.
PHYSICAL AGENTS
67

7. 7
DRY HEAT
Principle-
- Protein denaturation.
- Oxidative damage.
- Toxic effects of elevated levels of
electrolytes.
67

8. HOT AIR OVEN:-
 It’s the most widely used mode of sterilization
 Temp.- 160°C ( 320° F ) for 1-2 hr.
 Uses :-
- Glasswares like glass syringes, petridishes, flasks, pipettes & test
tubes.
- Surgical instruments like scalpels, scissors, forceps etc..
- Chemicals such as liquid paraffin, fats, greases, Sulphonamide,
dusting powder etc..
867

9.  Precautions:-
1) Not to be overloaded.
2) Must be fitted with fans for even distribution of hot air.
3) Materials to be sterilized should be perfectly dry.
4) Rubber materials (except silicone rubber) will not
withstand the temperature.
5) Allowed to cool for 2 hrs before opening the doors.
9
Advantage:
Economical.
Does not rust metals
Easily monitored .
Used for anhydrous
oils & powder.
Disadvantage :
Hot air is bad
conductor of heat
hence it has less
penetrating power
67

10. Temperature below 100°C – Pasteurization
Holder method : 63°C for 30 mins.
Flash process : 72°C for 20 sec…rapid cooling to 13°C.
Temperature at 100°C - BOILING
Temperatures - 90-1000C, 10 mins
Sporing bacteria require prolonged periods of boiling – 24hrs.
Sterilization may be promoted by..2% Na bicarbonate.
Tyndallisation or intermittent sterilization:-
- Used for media containing sugars or gelatin.
-Exposure of 100 degrees for 20 minutes on three successive days.
- First exposure kills all vegetative bacteria
-Subsequent exposure will kill the spores present
1067

11.  AUTOCLAVING (MOIST HEAT) STERILIZATION
Boiling water alone is INSUFFICIENT to kill spores and viruses
water boils when its vapour pressure equals to that of surrounding atmosphere
Hence, when pressure increases inside closed vessel
Temperature at which water boils increases
saturated steam has penetrative power
When steam comes in contact with a cooler surface it condenses to water
and gives up latent heat to that surface
1167

12. 12
AUTOCLAVE
 Three major factors for effective autoclave:
1. Pressure: 15psi.
2. Temperature: 121oC
3. Time: 15 mins.
 Higher temperature and pressure require shorter time for
sterilisation.
Pressure (psi)
• 15
• 20
• 20
Temperature
(°C)
• 121
• 126
• 134
Time (mins)
• 15
• 10
• 3
67

13. WORKING OF AN AUTOCLAVE
1367

14. 1. Ensure complete air removal for
temperature to reach 121°C.
2. Ensure loose packing in the chamber.
3. Tightly sealed materials may become
dangerously pressurized causing injury
when removed.
14
Considerations during autoclaving
USES:
Disposable syringes, Non disposable syringes, Glassware, Metal
instruments, surgical dressing, Surgical instruments, Laboratory
equipment, Culture media, Pharmaceutical products.
67

15. 15
Advantage:-
Economical.
Good penetration.
Short cycle time.
Easily monitored
No special
chemicals or
exhaust required.
Disadvantage:-
Moisture retention
Causes corrosion
Carbon steel gets
damaged
Dulling of unprotected
cutting edges.
Destruction of heat
sensitive materials.
67

16. Method Temperature Holding time
Autoclave 1210C 15min
126 0C 10 min
134 0C 3 min
Hot air oven 1600C 45min
170 0C 18min
180 0C 7.5min
*Recommendations of the medical research council.
1667

17.  Glass bead "sterilization" uses small glass
beads (1.2-1.5 mm diameter) and high
temperature (210 oC -230oC) for 10-30 seconds
to inactivate microorganisms.
 Use- endodontic files, burs
 Disadvantage:- no uniform heat.
1767

18. FILTRATION
Candle Filter Asbestos Filter
18
Sintered Glass Filters Membrane Filters
67

19. RADIATION
1) Non-ionising radiation:
 Uses longer wavelength and lower energy. And hence lose the ability to
penetrate substances, and can only be used for sterilizing surfaces
 Eg. infrared radiation is used for rapid mass sterilization of prepacked
items eg. Syringes, catheters.
 UV radiation is used for disinfecting enclosed areas like operation
theaters, laboratories.
2) Ionising radiation:
 Uses short wavelength, high-intensity radiation with high penetrative
power to destroy microorganisms.
 This radiation can come in the form of gamma or X-rays that react with
DNA resulting in a damaged cell.
 Since there is no appreciable increase in the temperature, it is also
known as COLD STERILIZATION.
 Used for sterilizing plastics, swabs, metal foils etc.
1967

20. ULTRASONIC CLEANING
 More effective than manual cleaning.
 Removes dried serum, whole blood, plaque, zinc phosphate and
polycarboxylate cements from instruments, metal surfaces and dentures.
 Minimizes handling of contaminated instruments.
 During cleaning, totally submerge instruments in the ultrasonic solution for
2 to 20 minutes .
 Ultrasonic solution should be changed atleast once a day.
2067

21. BIOLOGICAL CONTROLS FOR DIFFERENT
STERILIZATION METHODS
METHOD OF STERILIZATION BIOLOGICAL CONTROL
Hot Air Oven Bacillus subtilis subsp. Niger
Clostridium tetani
Autoclave Bacillus stearothermophilus
Filtration Serratia marcescens,
Pseudomonas diminuta
Ionizing Radiation Bacillus pumilis
21
67

22. 22
• The CDC recommends that flash sterilization not be used
routinely in the dental office to sterilize patient
instruments—this process should only be used in
unavoidable situations.
67

23. CHEMICAL AGENTS
LIQUIDS GASES
• Alcohols
• Aldehydes
• Phenols
• Halogens
• Heavy Metals
• Surface Active Agents
• Dyes
• Formaldehyde
• Ethylene Oxide
• Plasma
2367

24. MODE OF ACTION OF CHEMICAL AGENTS
 Protein coagulation
 Disruption of the cell membrane
 Removal of the free sulphydryl groups
 Substrate competition
2467

25. ALCOHOL
Mechanism of Action : Denaturation of Proteins
 Isopropyl alcohol
 70% ethyl alcohol
Methyl alcohol is active against the fungal
spores and used to treat cabinets and incubator
Suitable for skin preparation before
venepuncture
Disadvantage : . Inflammable
. Mucous membrane irritant.
. Promotes rusting.
25
Used as a skin disinfectant
67

26. 26
Aqueous soultion: Formalin(37% solution)
- 10% formalin + 0.5% Na tetraborate used to clean
metal instrument e.g. Endoscope, dialysis equipment.
Gaseous form: Fumigation of wards/corridors/ICU’s
Have pungent odour & irritating effect on skin & mucous membrane.
ALDEHYDES
A)Formaldehyde (formalin)
In aqueous solution it acts as a bactericidal and
sporicidal
Active against Gram -ve bacteria, spores,
viruses (HB, HIV) & fungi
67

27. . GLUTARALDEHYDE / CIDEX ( 2% alkaline NaHCO3 ):-
 High level disinfectant
 Especially active against tubercle bacilli,fungi and viruses
 Less toxic than formaldehyde
 Can be safely used to treat corrugated rubber anaesthetic tubes, face
masks, metal instruments.
 Exposure time: > 10hrs.
2767

28. PHENOLS:
Acts by cell membrane damage thus releasing cell contents and
causing lysis
 Eg. Cresol ( LYSOL) ,chlorhexidine ( SAVLON),chloroxylenol (DETTOL)
and hexachlorophene
 Phenol is commonly found in mouthwashes, scrub soaps and surface
disinfectants
 Low efficiency disinfectant
 Used for decontamination of the hospital environment, including
laboratory surfaces, and noncritical medical items.
2867

29. HALOGENS :
A) Chlorine compounds:
 Bleaching powder or hypochlorite solution mostly used
disinfectant for HIV infected material.
 in concentration of 0.05 or 0.5% used for surface material
and instruments disinfection
 Should be prepared daily because of instability of sodium
hypochlorite solution
 Active against bacteria, spores, fungi and viruses (HB, HIV)
2967

30. IODOPHORS & IODINE
 Active against bacteria, spores & some viruses & fungi
 Suitable for skin preparation, mouthwash & as a surgical scrub
(7.5% Povidone+iodine= Betadine)
3067

31. ETHYLENE OXIDE
• Highly inflammable and in concentration more than 3% highly explosive
and hence not used for fumigation of rooms
• Mix with carbon dioxide or nitrogen to eliminate its explosive tendency
• Alkylation of Amino, carboxyl, hydroxyl and sulphydryl groups in protein
molecules
• Effective against all types of micro-organism including
viruses and spores.
3167

32. PLASMA
 Any gas which consists of electrons, ions or neutral
particles
 Used along with chemical disinfectant like
hydrogen peroxide alone or with peracetic acid
 Eg. Sterrad 100 S sterilizer and plazlyte sterliser
32
Sterrad 100 S sterilizer
67

33. RECOMMENDED CONCENTRATIONS
DISINFECTANT CONCENTRATION
Ethyl Alcohol 70%
Gluteraldehyde 2%
Lysol 2.5%
Savlon (chlorhexidine and cetrimide) 2%, 5%
Dettol (chloroxylenol) 4%
Bleaching powder (Calcium hypochlorite) 14 gm in 1 L water
Sodium hypocholorite 1%, 0.1%
Betadine (Iodophore) 2%
33
67

34. STERILISATION AND
DISINFECTION IN
PROSTHODONTICS
3467

35. CLASSIFICATION OF
INSTRUMENTS
Critical
instruments
Semi-critical
Instruments
Non-critical
Instruments
35
Penetrate the soft tissue
 Contact the bone
 Enter into or contact
the blood stream
They should be
thoroughly cleaned and
heat sterilized if they are
to be reused.
Eg: Surgical instruments,
Scalers, Scissors
Surgical dental burs
Scalpel blades
Forceps
Contact the mucous membrane
but will not penetrate the soft
tissue
Eg : Mouth mirror, impression
trays, handpieces, probe,
tweezers
STERILIZATION OR HIGH LEVEL
DISINFECTION must be done
Come into contact with intact
skin
Eg : X-Ray tubes, Light handles,
Counter tops
LOW LEVEL DISINFECTION
67

36. IMPRESSION TRAYS
 Metallic : Autoclave
 Plastic : Ethylene Oxide
 Custom tray made of acrylic
resin : Discard
36
67

37. DISINFECTING IMPRESSIONS
 Methods
 Spraying
 Immersion
 Iodophors, sodium hypochlorite (1:10 concentration), chlorine
dioxide, phenols,formaldehyde,glutaraldehyde
3767

38. DISINFECTION OF ALGINATE IMPRESSIONS
 0.5% sodium hypochlorite
 iodophors
38
Immersion disinfection for prolonged periods will
cause distortion due to imbibition
67

39. AGAR- REVERSIBLE HYDROCOLLOID
 Found to be stable when immersed in 1:10 dilution sodium hypochlorite
or 1:213 iodophor.
 Recommended immersion time is 10 minutes.
ZINC OXIDE EUGENOL
 Immersion in 2% glutaraldehyde
 Iodophors or Chlorine compounds.
 Adverse effect have been reported on ZOE immersed for 16 hours in
diluted hypochlorite
39
IMPRESSION COMPOUND
 Immersion in 1:10 dilution sodium hypochlorite or iodophor for
specified time period.
67

40. ELASTOMERIC IMPRESSION MATERIALS
40
 Polysulphide and Addition Silicone:
 Glutaraldehyde, Iodophor, 0.5% sodium hypochlorite should be used
 Polyether:
 Spray and wipe in iodophor, 0.5% Sodium hypochlorite should be used.
 Prolonged immersion causes some distortion.
 Polyether shows dimensional changes on immersion in 2%
glutaraldehyde.
67

41. 41
 An in vitro study to evaluate the effect on dimensional changes of
elastomers during cold sterilization
 24 specimens: Polyether, polyvinyl siloxane (PVS) (heavy body), PVS
(regular body) and Hydrophilic addition reaction silicone
(medium body)
 2 disinfectants :2% glutaraldehyde and 0.525% sodium hypochlorite
 Result: PVS (heavy body) was most stable, and polyether was least stable of all the
impression materials.
 Khinnavar PK, Dhanya Kumar B H, Nandeeshwar D B. An in vitro study to evaluate the
effect on dimensional changes of elastomers during cold sterilization. J Indian Prosthodont
Soc 2015;15:131-7
67

42. OCCLUSAL RIMS AND WAX BITES
 Wax rims and wax bites are
disinfected using an iodophor,
chlorine dioxide, or sodium
hypochlorite spray and a "spray-
wipe-spray" technique. Following the
second spray, the wax bites can be
enclosed in a sealed plastic bag for
the proper contact time.
 Immersion disinfection may cause
distortion to some items
4267

43. DENTAL CASTS
 Spraying until wet or Immersing in a
1:10 dilution of sodium hypochlorite
or an iodophor then rinse
 Casts to be disinfected should be
fully set (i.e. stored for at least 24
hours)
 Microwave irradiation of the casts
for 5 minutes at 900 W gives high
level disinfection of the gypsum
casts .
43
 ADA recommends use of :
 Chlorine compounds
 Iodophors
 Combination of synthetic phenols
 Glutaraldehyde.
67

44.  To evaluate the effectiveness of disinfecting solutions incorporated into
dental stone casts against a standard and representative group of
microorganisms and to note changes in the physical properties of the casts.
 Irreversible hydrocolloid impressions were contaminated individually with
Escherichia coli, Staphylococcus aureus, Candida albicans etc..
 4 disinfecting solutions: glutaraldehyde, povidone-iodine, chlorhexidine and
sodium hypochlorite were added to the die stone mix used to pour up the
impressions.
 The physical properties assessed were setting time, setting expansion,
compressive strength, detail reproduction and delayed expansion of the
stone.
 RESULTS: 2% glutaraldehyde was the most effective disinfectant with the
least adverse effects on the physical properties of the set cast
Povidone-iodine caused a decrease in the compressive strength of
the set cast, but can be considered as an alternative.
44
Disinfection of dental stone casts: antimicrobial effects and
physical property alterations.
67

45. ACRYLIC DENTURES
 Sodium hypochlorite is recommended.
 Iodophors can also be used
4567

46. REMOVABLE CAST PARTIAL DENTURES
 ADA recommendation :
immersion in iodophor or
chlorine compounds.
 Damage of heat cured denture
base resin has been shown to
occur after only 10 minutes of
immersion in glutaraldehyde.
4667

47. FIXED PROSTHESES
 Immersion in glutaraldehyde OR
dilute hypochlorite
 A completely metallic prostheses
can be sterilized with ethylene
oxide or even by autoclaving
47
67

48. ROTARY INSTRUMENTS - BURS
 Diamond and carbide burs:
After use they are placed in 0.2% gluteraldehyde and
sodium phenate (Eg. Sporicidin) for at least 10 minutes,
cleaned with a bur brush or in an ultrasonic bath. Sterilize
in an autoclave or dry heat sterilize after cleaning.
 Steel burs:
May get damaged by autoclaving. Can be sterilized by
using a chemical vapor sterilizer or glass bead sterilizer at
2300C for 20-30 seconds.
4867

49. INFLUENCE OF MICROWAVE STERILIZATION ON
THE CUTTING CAPACITY OF CARBIDE BURS
 This study compares the cutting capacity of carbide burs sterilized with microwaves and traditional
sterilization methods.
 Sixty burs were divided into 5 groups according to the sterilization methods: dry heat (G1), autoclave
(G2), microwave irradiation (G3), glutaraldehyde (G4) or control – no sterilization (G5).
 Conclusion: Sterilization by dry heat was the method that least affected the cutting capacity of the
carbide burs and microwave sterilization was not better than traditional sterilization methods
 Burs sterilized by chemical solution showed the lowest cutting capacity
67 49

50. Handpiece
 All dental hand pieces should be heat/pressure sterilizable
and must be sterilized in between patient sessions.
 Unit should be thoroughly scrubbed with soap and water to
remove external contamination, all traces of water are
removed prior to lubrication and sterilization.
 Can be sterilized using autoclave, chemical vapour or uv
radiations.
5067

51. Dental water unit line
51
Municipal
Supply OR
Wells
Dental Unit
Multi –
channel
Control Box
Hoses feeding
various
attachments
Water entering the Dental Unit contains 0 -100 Colony Forming
Units (CFU) per ml
Water leaving the handpiece may contain up to 100,000 CFU/ ml
ADA Guidelines : Not more than 200 CFU/ml
Flushing for 2 minutes in the morning and for 20–30 seconds between
patients should be considered the norm for dental surgery procedures
to remove bacterial growth that may have accumulated
67

52. IMPLANTS
 Pre sterilized with Gamma radiation
 In case the implants needs to be re-sterilized conventional
sterilization techniques are not satisfactory
 Steam sterilization should not be used as it results in contamination of
surfaces with organic substances
 Dry heat sterilization also leaves organic and inorganic surface residue
 Radio frequency glow discharge technique (RFGDT) or Plasma cleaning
is used.
 In this, material to be cleaned is bombarded by high energetic ions
formed in gas plasma in a vacuum chamber.
 Removes both organic and inorganic contaminants.
5267

53. Waste Management
 Categories of bio-medical waste in india
Options Waste category
Category 1 Human anatomical
waste(tissues ,organs,body
parts)
Category 2 Animal waste
Category 3 Microbiology and
biotechnology waste
Category 4 Waste sharps
(needles,syringe,scalpels…)
Category 5 Discarded medicine and
cytotoxic drugs
5367

54. Waste Management
Category 6 Solid waste(items contaminated with blood
and fluid including cotton dressing….)
Category 7 Solid waste (waste generated from
disposable items )
Category 8 Liquid waste(waste generated from
laboratory and washing cleaning …)
Category 9 Incineration ash
Category 10 Chemicals used in production of biological,
chemical used in disinfection
5467

55. COLOUR CODING AND WASTE
DISPOSAL
COLOUR CONTAINER WASTE
CATEGORY
TREATMENT OPTIONS
YELLOW Plastic bag 1, 2, 3, 6 Incineration OR deep
burial
RED Plastic Bag 3,6,7 Autoclaving OR
microwaving OR
chemical treatment
BLUE / WHITE Puncture Proof
container
4, 7 Autoclaving OR
microwaving OR
chemical treatment OR
shredding
BLACK Plastic bag 5 ,9, 10 Disposal in secure landfill
5567

56. INFECTION AND
INFECTION CONTROL
56
67

57. BASIC CONCEPT OF INFECTION CONTROL
 Prevent spread of infection from the Clinician to the patient
 Prevent the spread of infection from the Patient to the Clinician
 Prevent the spread of infection from one patient to another
57
Patient
Operator
Other
personnel67

58. RECOMMENDATIONS FOR GLOVING
 Wear gloves when contact with blood, saliva,
and mucous membranes is possible
 Remove gloves after patient care
 Wear a new pair of gloves for each patient
 Remove gloves that are torn, cut or punctured
 Do not wash, disinfect or sterilize gloves for
reuse
5867

59.  Hegde et al in their study stated that the bar soap under the
"in use" condition is a reservoir of microorganisms and
washing hands with such a soap may lead to spread of
infection. (Microbial contamination of "in use" bar soaps in
dental clinics. Indian J Dent Res 2006;17:70-3)
59
67

60. FACE MASKS
 Protects face and eyes from contaminated splatter and
inhalation of contaminated aerosols
 It is essential when choosing a face mask to note that;
 It has a bacterial filtration efficiency of 95% or more.
 Does not contact nostrils or lips.
 It has both high filtration of small particles and
tolerable breathability.
 Close fit around entire periphery.
 Does not cause fogging of eye glasses.
60
Facemasks should be changed once every hour or
between each patient contact, whichever occurs
first.
67

61. OCCUPATIONALLY ACQUIRED INFECTIONS
 HIV : 0.3%
 Hepatitis C : 1.8%
 Hepatitis B (HBeAg +ve) : 30%
 Occupational exposures that may result in HIV, HBV, or HCV transmission
include needlestick and other sharps injuries; direct inoculation of virus
into cutaneous scratches, skin lesions, abrasions, or burns; and
inoculation of virus onto mucosal surfaces of the eyes, nose, or mouth
through accidental splashes
 All health care professionals should be immunized against Hepatitis A,
Hepatitis B, Varicella, MMR, DPT, Rubeola, Meningitis, Polio, Influenza,
Tetanus, Diptheria, Rubella.
61
67

62. Post exposure prophylaxis-HIV
 Wound care:
 Clean wounds with soap and water
 Flush mucous membrane with water.
 No evidence of benefit for: – application of antiseptics or disinfectants
– squeezing puncture sites
 Chemoprophylaxis
 Initiating occupational 4 week regimen of PEP as soon as possible,
ideally within 2 hours of exposure.
 HIV- antibody testing should be performed for atleast 6 months post
exposure
6267

63. CONCLUSION
 A steady increase in the serious transmissible diseases over the last
few decades have created a global concern and impacted the
treatment mode of all health care practitioners.
 Emphasis has now expanded to assuring and demonstrating to patients
that they are well protected from risks of infectious disease.
 The dental health care provider has to follow high standards of
infection control for the safety of the patients and the dental health
care workers
6367

64. References
 Textbook of Microbiology, 7th edition – Ananthanarayan and Paniker
 Textbook of Microbiology – C.P. Baveja
 Infection Control in Dental Practice – S. Anil, L.P. Samaranayake, Georges Krygier
 Essentials of Preventive and Community dentistry, 4th Edition - Soben Peter
6467

65. Cross References
 Infection control in prosthodontics rachuri narendra kumar , karthik K S , sudhakara V
maller JIADS VOL -1 issue 2 april - june,2010 |22
 An in vitro study to evaluate the effect on dimensional changes of elastomers during
cold sterilization.Khinnavar pk, dhanya kumar b h, nandeeshwar d b. J indian
prosthodont soc 2015;15:131-7
 Efficacy of various disinfectants on dental impression materials the internet journal of
dental science 2009, volume 9 number 1, sukhija et al
 Guidelines for infection control in dental health-care settings – 2003
 Risk and management of blood-borne infections in health care worker Clin microbiol
rev. 2000 jul; 13(3): 385–407
 Influence of microwave sterilization on the cutting capacity of carbide burs J appl oral
sci. 2009;17(6):584-9
6567

66. 67 66