Acute radiation syndrome 34 /certified fixed orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

ContentsContents
Introduction
Radiation biology
Radiation Chemistry
Effects of Radiation
Relevance of Radiation Exposure in
orthodontics
Radiation Protection
Bibliography

Introduction
X-rays are a form of electromagnetic radiation
Ability to ionize matterwhich is the initiating
event in radiation induced biologic changes

RADIATION BIOLOGYRADIATION BIOLOGY
 IS THE STUDY OF THE EFFECTS OF
IONIZING RADIATION ON THE LIVING
SYSTEM.

 Deterministic Stochastic
Severity of response probability of a
proportional to dose response occur

RADIATION CHEMISTRYRADIATION CHEMISTRY
 Free radical production
 RH + Photon R + H+
+ e
 These free radicals are unstable ,short lived and highly
reactive.
 Fate of the free radical _
1) Dissociation
R X + Y
2) Cross linking
R + S RS

thus there is formation of structurally and
functionally biologic molecules differing from
original molecule.there by inducing biological
change.

 Radiation acts on living system either
DIRECT INDIRECT
Direct ionization of biologic photon absorbed by
H2O
macromolecules with H2O IONIZED
formation of unstable free
radicals. Resultant free
radical
interact and
change the
macro moleculewww.indiandentalacademy.com

Radiosensitvity and cell typeRadiosensitvity and cell type
 Most radiosensitive cells are are
1)undergoing mitoses
2)having a high mitotic rate
3)are most primitive in differentiation

 Cells are usually divided into five categories of
radiosenstivity
1)vegetative inter mitotic cells
2)differentiating inter mitotic cells
3)multipotential connective tissue cells
4)reverting post mitotic cells
5)fixed post mitotic cells

)vegetative intermitotic cells—most radiosensitive
Eg:precursor cell–
spermatogenicerythoblastic ,basal cells of the oral
mucous membrane.
2)differentiating intermitotic cells –Eg: intermediate
cells of hemapoietic ,replicating cells of the inner
enamel epithelium

 Multi potential connective tissue cells –
---Eg intermediate radio sensitivity
--- : endothelial cells,fibroblasts
 Reverting post mitotic cells ---radio resistant
---Eg: acinar and ductal cells of salivary gland and
pancreas,parenchymal cells of liver ,kidney and
thyroid
 Fixed post mitotic cells---most radioresistant
---Eg:neurons ,striated muscle cells ,squamous cells
close to the surface of oral mucous membrane and
erythocytes

High Intermediate Low
Lymphoid Fine vasculature Optic lens
Bone marrow Growing cartilage Mature
Growing bone eryhtocytes
Intestines Salivary glands Muscle
Mucous Lungs cells
membrane Kidney Neurons
Liver
Relative Radio sensitivityRelative Radio sensitivity
of Various Organsof Various Organs

Radiation effects may be spoken In terms :-
the short term effects which bring about …
mitosis linked cell death
the long term effects that bring about….fibro
atrophic cell death

Short term effectsShort term effects
 Primarily determined by the sensitivity of the
parenchymal cells of the respective
tissue
 Raidly proliferatingcell loss mitosis linked
reduction in the number of mature cells .
 In tissues that undergo little proliferation the
radiation induced hypoplasia is not evident

Long Term EffectsLong Term Effects
Determined by the extent of damage to the
fine vasculature of the tissue
Endothelial cells---multi potential
connective tissue cells---intermediate radio
sensitivity..
Thus over a period of time ---capillaries
,degenerate and undergo necrosis.
Permeability increased

 progressive fibrotic processes begins
around the capillaries
This fibrotic scar tissue will eventually
cause obliteration of blood vessels---
depriving the cells of nutrition ,oxygen
and elimination of waste
Eventually leading to loss of cell function
,decreased resistance to infection and death
of all cell types…with the net result of
PROGESSIVE FIBROATROPHY

Oral mucousOral mucous
membranemembrane

• Oral mucous membrane
* Short term effects –related to the radiosensitive
vegetative intermitotic cells of the basal layer of the
mucous membrane.
* Initially —redness and inflammation—mucositis
*as therapy continues – formation of whitish yellow
pseudomembrane—desquamated epithelial layer
*2 months after therapy—rapid healing---
• mucosa becomes atrophic,thin relatively
avascular.

Taste budsTaste buds
*are radiosensitive—extensive degeneration
*loss of taste acuity during second or third
week of radiotherapy
*recovery usually takes between 60-120 days

Salivary glandsSalivary glands
 The parenchymal component of salivary glands is
radiosensitive
 Short-term effects –inflammatory response
 Long-term effect progressive fibrosis,adiposis,loss
of fine vasculature with parenchymal
degeneration---accounting for xerostomia.
 Marked reduction of salivary flow is seen in the
1st
two weeks
 Xerostomia ,decreased ph of saliva (6.5to 5.5)---
this is low enough to cause decalcification
 Buffering capacity falls by 44%www.indiandentalacademy.com

Flora thus becomes more acidogenic in
saliva and plaque ---this along with thick
viscous ,acidic saliva---renders patient
susceptible to radiation caries. Oral micro
flora changes –strept.mutants,lactobacillus
and candidasis
Recovery—6 to 12 months
If not –unlikely that there will be significant
recovery

Radiation cariesRadiation caries
Rampant form of decay
 Irradiation of the teeth does not influence the
decay but the changes induced in the salivary
glands and saliva are responsible for this decay
 There are three types of radiation caries
-----superficial lesions—B,O,Li,P surfaces
-----primarily involving cementum and dentin
in the cervical region
-----dark pigmentation of the entire crown

Reducing ----daily application for 5 minutes
of a viscous topical 1% neutral NaF gel
--------avoidance of dietary sucrose

TeethTeeth

TeethTeeth
 Severity of damage is dose dependent
 If irradiation precedes calcification –tooth bud
destroyed
 After calcification has begun—inhibition of
cellular differentiation –malformations and
arresting growth
 Adult teeth are relatively radioresistant
 Pulpal tissue –reverting and fixed postmitotic cells
—may show long –term fibroatrophy
 No discrenible effect on the crystalline structure of
enamel ,dentin or cementumwww.indiandentalacademy.com

BoneBone
Primary damage—results from damage to
the vasculature of the periosteum and
cortical bone
Also the radiation tends to destroy
osteoblasts and to a lesser extent osteoclasts
Bone marrow fatty bone marrow and
fibrous connective tissue
 marrow  hypo vascular,hypoxic and
hypo cellular
Degree of mineralization reduced brittle

OsteoradionecrosisOsteoradionecrosis
Decreased vascularity -renders bone
susceptible to infections
Source of these infections may be from
radiation –induced breakdown of the oral
mucous membrane ,mechanical damage
tooth extraction ,denture sore,PD lesion
or radiation caries...
Mandible > maxilla

Relevance of Radiation
in Orthodontia

Relevance of Radiation inRelevance of Radiation in
OrthodontiaOrthodontia
• Most commonly taken radiographs in
Orhtodontia are :-lateral cephalogram
panoramic radiograph
• hand- wrist x-rays
• Exposure of critical organs which are:-
active bone marrow
thyroid gland
salivary glands
optic lenswww.indiandentalacademy.com

 Exposure is of low doses …example for the
formation of cataract 2Sv(200 rem)but in opg
dose exposed to in the form of scattered radiation
is only 80 microSv
 Also studies by Danforth and Gibbs
 Thyroid160-370 microGys
 Pitutary 70-490 microGys
 Salivary glands 393 microGys
 As these doses are well below the maximum
permissible dose the harmful effects still remain
uncertain

Harmful effects manifest as increased
probability of a normally occurring disease
Bear in mind ALARA principle

Maximum Permissible DoseMaximum Permissible Dose
 Two categories :-ouupationally exposed
 Non occupationally exposed
Whole body Isolated areas of
body
Occ.exp. 0.05Svyear 0.75Svyear
Non occ. 0.005Svyear 0.075Svyear
Exp.

Radiation SafetyRadiation Safety
Two aspects:-
Patient Protection
Protection of Personnel

Patient protection
1) Intensifying screens
2) Focal spot to film distance
3) Collimation
4) Filtration
5) Lead aprons and collars
6) Good radiographic techniques

Protection of PersonnelProtection of Personnel
Barrier/position and distance rule
Operator never hold film
Personnel should wear film badges
Regular checks of x-ray equipment for
spills

 IS A COLLECTION OF SIGNS AND
SYMPTOMS EXPERIENCED BY PERSONS
AFTER ACUTE WHOLE BODY EXPOSURE
TO RADIATION
1)Prodromal Period
2)Hematopoietic Syndrome
3)Gastrointestinal Syndrome
4)Cardiovascular Syndrome
Acute Radiation SyndromeAcute Radiation Syndrome

PRODROMAL PERIODPRODROMAL PERIOD
WITHIN FIRST MINUTES TO HOURSAFTER
EXPOSURE ,SYMPTOMS OF
GASTROINTESTINAL TRACT
DISTURBANCES MAY OCCUR.
ANOREXIA,NAUSEA
VOMITTING,DIARRHEA,WEAKNESSAND
FATIGUE
SEVERITY AND TIME OF ONSET R DOSE
RELATED

LATENT PERODLATENT PEROD
PERIOD OF APPARENT WELL BEING
EXTENT OF LATENT PERIOD IS DOSE
RELATED

HEMATOPOIETIC SYNDROMEHEMATOPOIETIC SYNDROME
 2 TO 7 Gy CAUSES INJURY TO THE
HEMATOPOETIC STEM CELLS OF THE
BONE MARROW AND SPLEEN.
 FALL IN THE NUMBER OF
CIRCULATING
GRANULOCYTES’PLATELETS,AND
ERTHROCYTES.

THE CLINICAL SIGNS OFTHE CLINICAL SIGNS OF
THE HEMATOPOIETICTHE HEMATOPOIETIC
SYNDROME INCLUDE-SYNDROME INCLUDE-
1)INFECTION-LYMPHOPENIAAND
GRANULOCYTOPENIA
2)HEMORRHAGE—
THROMBOCYTOPENIA.
3)ANEMIA—ERYTHOCYTE
DEPLETION
IF PATIENT DOES NOT RECOVER DEATH
MAY OCCUR IN 10 TO 30 DAYS.

GASTROINTESTINALGASTROINTESTINAL
SYNDROMESYNDROME
7 to 15 Gy causes extensive damage to the rapidly
proliferating epithelial cells of the intestinal villi
with resultant –denudation of mucosal surface
,loss of plasma and electrolytes
these changes are responsible for
diarrhea,dehydration,and weight losses well
as invasion of endogenous intestinal bacteria
producing septicemia.

These damages along with the hematopoietic
damage together contribute to the signs and
symptoms of GASTROINTESTINAL
SYNDROME

CARDIOVASCULAR AND CENTRALCARDIOVASCULAR AND CENTRAL
NERVOUS SYSTEM SYNDROMENERVOUS SYSTEM SYNDROME
Exposure to a dose in the range of 50Gy will
cause death in a few minutes to 2 days
There is collapse of the cardiovascular
system and autopsies reveal necrosis of the
cardiac muscle .
Damage to the nervous system manifests as
patient showing intermittent stupor ,inco-
ordination,disorientation and convulsions

ContentsContents
 Introduction
 Mechanisms of Cross Infection
 Important Pathogens in Infection Control
 Control of Cross-Infection
 Sterilization in Orthodontics

Pathways for Cross-Contamination
Patient to dental team
Dental team to patient
 Patient to patient
 Dental office to
community
Modes of disease spread :-Direct contact
Indirect contcat
Droplet infection
IntroductionIntroduction

Mechanism or site of entry into
body:-
through breaks in
skinmucous membrane
through inhalation

There are several important disease in
infection control but the ones of most
significance in the dental office are:-
Hepatitis B virus
HIV
Herpes Simplex Virus

Infectious agent Disease or condition Route of
transmission
Incubation period Communicable
period
Hepatitis A virus ‘Infectious hepatitis’
Type A Hepatitis
Feco-oral, Food ,
water, shellfish
2 to 6 wks (av. 28
to 30 days)
2 to 3 wks before
onset (jaundice)
through 8 days
after
Hepatitis B Virus ‘Serum hepatitis’ Type
B Hepatitis
Blood, saliva, body
fluids,sexual
contact, perinatal
2 to 6 months ( av.
60 to 90 days )
Before, during &
after clinical signs
Carrier state:
indefinite
Delta Hepatitis
Virus ( HDV )
Delta Hepatitis Coinfection with
HBV, Blood,
Sexual contacts,
Perinatal
2 to 10 weeks All phases
Non-A, Non-B
Hepatitis Virus
Non-A, non-B hepatitis Similar to HBV 2 to 6 months Like HBV
Epidemic non-A non-B Feco-oral
Contaminated
water
15 to 64 days Not known. Maybe
like HAV
Human
Immunodeficienc
y Virus ( HIV )
Acqired
Immunodeficiency
Syndrome ( AIDS )
Blood & blood
products
( infected i.v
needles ), sexual
contact, perinatal,
3 months to 5
years
2 years for
transfusion case )
From
asymptomatic
through onset of
opportunistic
infections

Herpes Simplex
Virus
Type I ( HSV -1 )
Type II (HSV-2 )
Acute Herpetic
gingivostomatitis
Herpetic labialis
Ocular herpetic
infections
Herpetic Whitlow
Saliva, direct
contact ( lip, hand )
Indirect contact
(on objects, limited
survival)
Sexual contact
2 to 12 days Labialis: one day
before onset until
lesions are crusted
Acute stomatitis:
7wks after
recovery
Asymptomatic
infection: with viral
shedding
Reactivation
period: with viral
sheddingVaricella-zoster
virus (VZV)
Chickenpox
Shingles
Direct contact
Indirect contact
Airborne droplet
2 to 3 weeks 5 days prior to
onset of rash until
crusting of vesicles
Epstein- Barr Virus
( EBV )
Infectious
mononucleosis
Direct contact
Saliva
4 to 6 weeks Prolonged
Pharyngeal
excretion 1yr after
infection
Cytomegalovirus
( CMV )
Neonatal CMV
infection
CMV disease
Perinatal
Direct
contact(most body
secretions)
Blood transfusion
Inexact
3 to 8wks after
transfusion
Months to years

Treponema
pallidum
Syphilis Direct contact
Transplacental
10 days to 10 weeks Variable and
indefinite
Maybe 2 to 4 years
Neisseria
gonorrhoea
Gonorrhea Direct contact
Indirect contact
(short survival of
organism)
2 to 9 days During incubation
Continued for
monthsand years if
untreated
Group A
streptococci
(Beta-hemolytic)
Streptococcus
pyogenes
Streptococcal sore
throat
Scarlet fever
Impetigo
Erysipelas
Respiratory
droplets
Direct contact
1 to 3 days 10to 21 days,
untreated
Many nasal
oropharyngeal
carriers
Staphylococcus
aureus
Staphylococcus
epidermidis
Abscesses
Boils (furuncles)
Impetigo
Bacterial
pneumonia
Saliva
Exudates
Nasal discharge
4 to 10 days
Variable and
indefinite
While lesions drain
and carrier state
persists

Influenza
viruses
Influenza Nasal discharge
Respiratory
droplets
24 to 72 hrs 3 days from
clinical onset
Measles Virus
(Morbilivirus)
Rubeola (measles) Direct contact
Saliva
Airborne droplets
8 to 13 days to
fever, 14 days to
rash
Few days before
fever to 4 days
after rash appears
Rubella virus
(Togavirus)
Rubella (German
measles)
Nasopharyngeal
secretions
Dirrect contact
Airborne droplets
16 to 23 days From 1wk to at
least 4 days after
rash appears
Congenital Rubella
Syndrome
Maternal infection,
first trimester
Infants shed virus
for months after
birth
Mumps virus
(Paramyxovirus
)
Infectious parotitis Direct contact
(saliva)
Airborne droplets
2 to 3 wks
(average 18 days)
From 1 to 7 days
before sympoms
until 9 days after
swelling
Polio virus
types 1,2,3
Poliomyelitis Direct contact
(saliva), Droplet,
Feco-oral
7 to 14 days Probably most
infectious 7 to 10
days before and
after onset of
symptoms
Mycobacteriu
m Tuberculosis
Tuberculosis Droplet nuclei
Sputum
Upto 6 months Long, repeated
exposure usually

 An infection-control program comprises two distinct
areas: exposure control and hazard
communication.
 Exposure control covers sterilization and disinfection,
waste management, and employee including personal
protective equipment and bodily-fluid-exposure
protocols.
 Hazard communication requirements include a periodic
checklist for OSHA compliance, drills for hazard
communication plans (chemical spills, emergency first
aid, and fire or tornado evacuation), secondary labeling of
hazardous chemicals, Material Safety Data Sheets, x-ray
updates, and properly displayed state and federal posters.www.indiandentalacademy.com

TerminologiesTerminologies
 Sterilization it is the process of destroying all
forms of microbial life
 Disinfection it is defined as the removal of or
inactivation of microbes.thus it implies only some
and not all pathogenic organisms can be
eliminated by this method.
 Anti-septicsthese are substances that prevent
the growth or action of microbes by either
destroying them or inhibiting their actions

Sanitizersreduce the microbial population to
safe levels as judged by public health
requirements.they are usually chemical agents that
kill close to 99.9%of the organisms.
Germicideskill the growing forms but not
necessarily the resistant spores.
Bacterio static agents agents which have the
ability to inhibit he growth of bacteria.

SterilizationSterilization
Is a process intended to kill all
microorganisms whether vegetative or
pathogenic .
It is the highest level of microbial killing
that can be achieved

The protocol for sterilization of instruments
is usually
1)holdingpresoaking
2)pre cleaning
3)sterilization process
4)aseptic storage and handling of
instruments

Holding PresoakingHolding Presoaking
If instrument not to be cleaned immediately
soak in holding solution prevents
salivablood from drying up.
Holding solution usually is a germicidal
Discard solution at least once a day
Avoid prolonged soakingcorrosion

Pre cleaningPre cleaning
Reduces amount of microbes present ,but
more importantly removes blood saliva and
other materials that may insulate microbes
from the sterilizing agent.
May be achieved by
ultrasonic
manual

Sterilization ProcessSterilization Process
A) Physical agents
B) Sunlight
C) Dry heat:-
flaming
incineration
hot air
D) Moist heat :
 boiling
steam under pressure
E) Filtration:-
membranes
asbestos padswww.indiandentalacademy.com

F) Ultraviolet light
G)Radiation
H)Micro-wave
I)Lasers

In dentistry the procedures used are:-
1)Heat sterilization
2)Gaseous sterilization
3) Liquid chemicals sterilization

Heat sterilizationHeat sterilization
a) Moist heat:-steam pressure autoclave
b) Unsaturated chemical vapour:- chemiclave
c) Dry heat:- conventional dry heat ovens
:- short cycle high temperature dry
heat ovens

Steam Pressure AutoclaveSteam Pressure Autoclave
 Sterilizes by bringing about oxidation as well as
denaturing proteins
 It is the latent heat and not the pressure built
inside by steam within the closed chamber that is
responsible for killing of the microbes
 Two cyclesStandard..20 –30 mins.at 250°f
Flash cycles..3-10 mins.at 273°f

Advantages time efficient,good
penetration
Disadvantages 1)may lead to corrosion
of susceptible instruments.
2)items sensitive to
elevated temperatures get damaged

Unsaturated Chemical vaporUnsaturated Chemical vapor
Chemical solution heated in a closed
solution-chemical vapor kills the
microbes
0.23%formaldehyde,72.38%ethanol along
with acetone,ketone and water
20 min at 270°f

Advantages
1)eliminates or reduces the corrosion of
susceptible instruments.
2)dry instruments available at end of cycle
Disadvantages
1)items sensitive to elevated temp.will get
damaged
2)pre drying of inst.a must

ChemiclavveChemiclavve

Dry HeatDry Heat
 Conventional dry heat ovens
*heat chambers wherein heated air is circulated by
gravity convection
*320f for 30 min
*place packs at least 1 cm apart to allow for the hot
air to circulate between wrapped instruments

Short –cycle high temperature dry heat
ovens
Are force draft ovens
370°f to 375°f for 6 to 12 mins
Advantages :-1)instruments sensitive to
corrosion may be safely sterilized
2)effective rapid cycles are possible
3)items dry at end of cycle

Disadvantage
Instruments sensitive to elevated temp. will get
damaged
Ethylene oxide sterilization
 for complex, delicate , heat sensitive inst.
aeration of about 24hours must pror to use
of instruments especially porous and plastic
ones

Dry heat sterilizerDry heat sterilizer

Boiling waterBoiling water
Even though seen to be used commonly it
does not kill spores and does not bring
about sterilization of instruments
Heat reaches and kills the blood borne
pathogens
100° for 10 min.
Thus more than sterilization it is a process
of high level disinfections

Chemical MethodsChemical Methods
Chemical agents are used for controlling of
microbes on body surfaces and on
inanimate objects are grouped under
disinfectants
These includeantiseptics
sanitizing
degerming
disinfecting agents

Qualities of a universalQualities of a universal
disinfectantdisinfectant
1)destroy all forms of microorganisms
within a practical period of time
2)non-toxic,non-allergic,non-irritating
3)non-corrosive,non-discolouring ,non-
degrading
4)good wettability and penetrabilityfor
effective contact even in the presence of
blood and exudate
5)readily soluble in available solvents

ClassificationClassification
 Spaulding in 1972
A. High level disinfectants
Eg:-ethylene oxide gas,immersion
glutheraldehyde solutions
B. Intermediate level disinfectants
Eg:-formaldehyde ,chlorine
compounds,alochol,iodophors ad phenolic
compounds

C.Low level disinf.
Narrowest anti-microbial activity
Eg:- quaternary ammonium comps

Categories of chemicalCategories of chemical
disinf.disinf.
 A) Alcohols
 B) Aldehydes
 C) Halogens
 D) Surfactants
 E) Quanternary ammonium compounds
 F) Phenols and Phenolic compoundwww.indiandentalacademy.com

A. Alcohols
bactericidal and fungicidal but not
sporicidal
MOA :- denature proteins
solvent action on lipids
Ethyl and isopropyl alcohols…most
commonly used
optimum conc. 70% range 60-95%
If conc.falls below 45%antmicrobial
activity is slow and uncertain

Alkalating agents
Formaldehyde
Gaseous state …used as a fumigant
MOA :- protoplasmic poison
denaturing proteins
 Disadvantage:-pungent odour
,irritating t skin ,poor penetrating and
slow acting

Gluteraldehyde :-
less pungent volatile and irritating with
better disinfectant properties
broad spectrum of
activity2%sol.bactericidal,tubercu
locidal and virucidal in 10 mins and
sporicidal in 10 hours
gluteraldehyde+iodine comp.+bleach
recommended for use against Hb virus
where sterilization not feasible

They also have a low surface tension
and can thus penetrate blood and
exudate thus reaching instruments
surfaces
Also used for disinfection of
impressions
Cidex , sporicidin, glutorex

HalogensHalogens
Iodine
Iodophors
Chlorine

Chlorine
Sanitizing agent
Elemental chlorine used for water
purification
may also be used as a surface
disinfectant
conc. 2.5%
gloves must be worn
corrosive to metals

Iodine :- used for wound and skin
antisepsis
Tinctures of iodine are usually used in
1,5and 7% conc. Which destroy 90%of
bacteria in 90,60 and 15 sec.
respectively
• Iodophors:- composed of complexes
of iodine and surface active organic
carrier molecules from which iodine
gradually released .

SurfactantsSurfactants
Soaps :- degerm the skin by mecanical
removal of microbes
bacterostatic and bacteriocidial

Phenols :-
As disinfectants and antiseptics
MOA:-denaturing of proteins or damage to cell
membrane
Bacteroicidal and bacteriostatic…but poor
viricidal properties

 These include :-
 Gloves
 Mouth masks
 Protective eyewear
 Hand washing
 Immunization

GlovesGloves
The need for gloving
The practices of gloving not only
provides protection to dentist but also to
the patient

For eg:-
Dentist
dentist contracts
treats herpes…herpes
whitlox
patient with herpes simplex
to patients treated in future

Patient Care GlovesPatient Care Gloves
Disposable gloves
Do not wash gloves with detergents in an attempt
to reuse
While leaving chairside remove gloves
While working chair side try and put to use the
practice of double gloving

Protective EyewearProtective Eyewear
 Protection from microbes
 Eg:HSV, Hepatitis B
 Protection against physical damage
 Protection from impact damage
 Protection from splashes of chemicals

Preferable to use goggles over glasses as
former not only provides protection from
front splash and impacts but also from side
impacts and splashes

Hand washingHand washing
Two types of micro flora
 resident flora
transient flora

Resident flora:colonize and become
resident
can never be completely
eliminated
less imp. In causing
disease

Transient flora:acquired whilst dealing
with contaminated objectssurfaces
do not colonize or
survive for long periods on the hand
usually pathogenic
can be removed by
following a good hand washing protocol

Hand washing products containing low
levels of microbial agents used in a 10 –30
sec.hand wash routine minimizes the no.of
transient flora and aids in reducing the no.of
resident flora too.
Chlorhexidine digluconate ,povidine
iodine,parachlorometaxylonol
Washing of hands before and after gloving
very imp.

Commonly used HandCommonly used Hand
DisinfectantsDisinfectants

MasksMasks
Protect mucous membrane of mouth and
nose from contact with
aerosolssprayssplashes of oral fluids from
patients…also in turn protect patient
Composed of material that filters out 95%-
99.9%of 2-3 micrometer size particles that
directly contact it
They should be form-fitting over the bridge
of the nose to reduce fogging of eyewear

Dispose mask once it gets moist
resistance to airflow through the mask
increasesmore unfiltered air is allowed to
pass by the edge of the mask
Use disposable maskschanging between
patients

ImmunizationImmunization
Hepatitis
The HBV is an infectious agent associated
with acute and chronic hepatitis .
Major cause of necrotizing vasclitis,cirrhosis ,
and primary hepatocellular carcinoma.
Found primarily in blood and blood products
…may also be present in other body
fluids…saliva , semen,tears,urine

Transmitted parenterally,sexual
contact,mother to fetus
HBV relatively environmentally stable…
potential for indirect transmission via
contact with contaminated inst.
Best protection is by immunization
Two vaccines Recombivax HB and
EngerixB
Regime :-1.0ml doses given at 0, 1, and 6
mths

Following vaccination protective levels of
antibodies are believed to persist for seven
years
Need for booster dose is being debated

Sterilization of OrthodonticSterilization of Orthodontic
PliersPliers
 autoclave or chemiclave .
The only major obstacle of pliers
sterilization is related to their corrosion
suceptibility.

 corrosion resistance of orthodontic grade
steel is directly proportional to its chromium
content and inversely proportional to its carbon
content .
disruption of chromium oxide layer renders them
suceptible to corrosion.
Instruments made of carbon or 400 series steel are
more susceptible than those made of 300 series
steel.

Steps to prevent corrosionSteps to prevent corrosion
 first be cleaned thoroughly and rinsed with
distilled water .
 do not allow contaminants to dry
Tap water to be avoided– use only distilled water

Chrome-plated instruments should be autoclaved
separately from stainless steel ones.
 Detergents with chloride bases should not be used
, Purple or black staining is caused by exposure to
ammonia.
*

ArchwiresArchwires
Contaminated archwires are sterilized in
divided plastic containers
Cut to appropriate length and kept
overnight in gluteraldehyde solution
Thereafter stored in binsuntil ready to be
used

Recycling of archwires
the relative high costs of archwires has lead to one
trying out the practice pf reclcycling of arch wires
Both cold and heat sterilization have been tried
Heating cycle should not exceed 235 C for a total
of 20 minsto keep impact on wires properties to
the minimum.

Studies on Recycling ofStudies on Recycling of
Orthodontic Arch wiresOrthodontic Arch wires

Mayshew ,Kusy Am.j.OrthoMayshew ,Kusy Am.j.Ortho
19881988
 Effect of sterilization on mechanical properties
and surface topography of 0.017” x 0.025”
NiTinol and Titanal wires
 Three methods:-
dry heat at 180 c for 60 min
formaldehyde alcohol vapour ,132c for 30 min
steam autoclave ,121 c for 20 min at 15-20 psi

Tests conducted:-
Three point bending—elastic moduli
Surface topography –laser scattering
Tensile properties—instron utm
Results:-
No significant change in tensile properties with
any sterilization procedure
No change in elastic moduli
No apparent effect on surface topography

Buckthal, Kusy :Am.J.Ortho .Buckthal, Kusy :Am.J.Ortho .
19981998
 Effects of cold disinfectabnts on mechanical
properties and surface topography of 0.017” x
0.025” NiTinol and Titanal wires
 Three disinfectants tested:-
2%acidic phetaraldehyde for 10 hours
 Cholorine dioxide for 6 hours
 Iodophor for 10 hours ..mixture at the ratio of
1/256 with water.

Tests :-
Bending ,tensile,laser spectroscopy
Results :-
No change in elastic moduli
No change in surface topography
No change in tensile properties

Laboratory AsepsisLaboratory Asepsis
 Counter tops:-wipe counter tops with effective
disinfectants.
 Impressions:-
easily contaminated with blood and saliva
microorganisms easily transferred from
contaminated impressions to casts where they can
remain viable for upto 7 days…thus providing a
path for cross contamination from the clinic to the
laboratory personnel

 Impressions after being removed from the mouth should
be rinsed under running water …this enables the removal
of adhering microorganisms
 They are then placed into plastic bags with appropriate
disinfectants for approximately 15 mins…followed by
their removal and rinsing of the disinfectant…they are
now ready to be poured
 If the impression is sensitive to immersion an alternate
would be to spray the impression with the appropriate
disinfectant and wrap it with a paper towel moistened with
the same disinfectant for 15 mins.

BibliographyBibliography
White and Pharoah: Oral
Radiology:Principles and Interpretations
Robert langleins,Olaf
e.langland,McDavid:Panoramic Radiogaph
Casebow, M.P.:patient doses from
Orthopantomograph x-ray exposures,Br. J.
Radiol.,46:230,1973

Chris H. Miller and Charles J.
Palenik:Infection Control and
management of Hazardous
Materials for the Dental Team
Mayshew,Kusy:Recycling of
orthodontic wires:Am. J. Ortho
1988
Buckthal,Kusy: Am. J. Ortho.1998

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