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









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

www.indiandentalacademy.com

Introduction


X-rays are a form of electromagnetic radiation



Ability to ionize matterwhich is the initiating
event in radiation induced biologic changes




IS THE STUDY OF THE EFFECTS OF
IONIZING RADIATION ON THE LIVING
SYSTEM.



Deterministic
Severity of response


proportional to dose
severity

Stochastic
probability of a

response occur
and not
hat is dose dependent






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
absorbed by H2O
macromolecules with
IONIZED
formation of unstable free
radicals.
free
and
change the
macro molecule

photon
H2O

Resultant
radical
interact



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



Relative Radio sensitivity
of Various Organs
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


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








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








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 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.

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













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%






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


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


Teeth












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 cementum











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








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


•

•
•

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 lens



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




Harmful effects manifest as increased
probability of a normally occurring disease



Bear in mind ALARA principle


Two categories :-ouupationally exposed
 Non occupationally exposed
Whole body
Isolated areas of
body
Occ.exp. 0.05Svyear
0.75Svyear


Non occ. 0.005Svyear
Exp.

0.075Svyear




Two aspects:Patient Protection
Protection of Personnel


Patient protection
1)
2)
3)
4)
5)
6)

Intensifying screens
Focal spot to film distance
Collimation
Filtration
Lead aprons and collars
Good radiographic techniques



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



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




PERIOD OF APPARENT WELL BEING
EXTENT OF LATENT PERIOD IS DOSE
RELATED




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.


1)INFECTION-LYMPHOPENIAAND
GRANULOCYTOPENIA
2)HEMORRHAGE—THROMBOCYTOPENIA.
3)ANEMIA—ERYTHOCYTE DEPLETION
IF PATIENT DOES NOT RECOVER DEATH
MAY OCCUR IN 10 TO 30 DAYS.


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


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 ,incoordination,disorientation and convulsions




Introduction



Mechanisms of Cross Infection



Important Pathogens in Infection Control



Control of Cross-Infection



Sterilization in Orthodontics

Introduction


Pathways for CrossContamination
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



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)

Hepatitis B Virus

‘Serum hepatitis’ Type
B Hepatitis

Blood, saliva, body
fluids,sexual
contact, perinatal

2 to 6 months ( av.
60 to 90 days )

2 to 3 wks before
onset (jaundice)
through 8 days
after
Before, during &
after clinical signs

2 to 10 weeks

Carrier state:
indefinite
All phases

2 to 6 months

Like HBV

15 to 64 days

Not known. Maybe
like HAV

3 months to 5
years

From
asymptomatic
through onset of
opportunistic
infections

Delta Hepatitis
Virus ( HDV )

Delta Hepatitis

Non-A, Non-B
Hepatitis Virus

Non-A, non-B hepatitis

Coinfection with
HBV, Blood,
Sexual contacts,
Perinatal
Similar to HBV

Epidemic non-A non-B

Feco-oral

Human
Immunodeficienc
y Virus ( HIV )

Contaminated
water
Acqired
Blood & blood
Immunodeficiency
products
Syndrome ( AIDS )
( infected i.v
needles ), sexual
contact, perinatal,

2 years for
transfusion case )

Herpes Simplex
Virus

Acute Herpetic
gingivostomatitis

Saliva, direct
contact ( lip, hand )

Type I ( HSV -1 )

Herpetic labialis

Type II (HSV-2 )

Ocular herpetic
infections

Indirect contact
(on objects, limited
survival)

Herpetic Whitlow

Varicella-zoster
virus (VZV)

2 to 12 days

Acute stomatitis:
7wks after
recovery

Sexual contact

Asymptomatic
infection: with viral
shedding

Chickenpox

Direct contact

Shingles

2 to 3 weeks

Reactivation
period: with viral
5 days prior to
shedding
onset of rash until
crusting of vesicles

4 to 6 weeks

Prolonged
Pharyngeal
excretion 1yr after
infection
Months to years

Indirect contact
Airborne droplet

Epstein- Barr Virus
( EBV )

Infectious
mononucleosis

Direct contact

Cytomegalovirus
( CMV )

Neonatal CMV
infection

Perinatal

Inexact

Direct
contact(most body
secretions)

3 to 8wks after
transfusion

CMV disease

Labialis: one day
before onset until
lesions are crusted

Saliva

Blood transfusion

Treponema
pallidum

Syphilis

Direct contact

10 days to 10 weeks

Transplacental

Variable and
indefinite
Maybe 2 to 4 years

Neisseria
gonorrhoea

Gonorrhea

Direct contact

Group A
streptococci
(Beta-hemolytic)

Streptococcal sore
throat

Respiratory
droplets

Streptococcus
pyogenes

Scarlet fever

2 to 9 days

Direct contact

Impetigo

Indirect contact
(short survival of
organism)

During incubation
Continued for
monthsand years if
untreated

1 to 3 days

10to 21 days,
untreated
Many nasal
oropharyngeal
carriers

Erysipelas

Staphylococcus
aureus

Abscesses

Saliva

4 to 10 days

Staphylococcus
epidermidis

Boils (furuncles)

Exudates

Impetigo

Nasal discharge

Variable and
indefinite

Bacterial
pneumonia

While lesions drain
and carrier state
persists

Influenza
viruses

Influenza

Nasal discharge

Measles Virus
(Morbilivirus)

Rubeola (measles)

Respiratory
droplets
Direct contact

Rubella virus
(Togavirus)

Saliva
Rubella (German
measles)

Airborne droplets
Nasopharyngeal
secretions

24 to 72 hrs

3 days from
clinical onset

8 to 13 days to
fever, 14 days to
rash

Few days before
fever to 4 days
after rash appears

16 to 23 days

From 1wk to at
least 4 days after
rash appears

Dirrect contact
Congenital Rubella
Syndrome
Mumps virus
(Paramyxovirus
)

Infectious parotitis

Polio virus
types 1,2,3

Poliomyelitis

Airborne droplets
Maternal infection,
first trimester
Direct contact
(saliva)

2 to 3 wks
(average 18 days)

Airborne droplets
Direct contact
(saliva), Droplet,

7 to 14 days

Feco-oral
Mycobacteriu
m Tuberculosis

Tuberculosis

Droplet nuclei


Sputum

Upto 6 months

Infants shed virus
for months after
birth
From 1 to 7 days
before sympoms
until 9 days after
swelling
Probably most
infectious 7 to 10
days before and
after onset of
symptoms
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.






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.






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








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


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



A) Physical agents
B) Sunlight
C) Dry heat:flaming
incineration
hot air
D) Moist heat :
 boiling
steam under pressure
E) Filtration:membranes
asbestos pads

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


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








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








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


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









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 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











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


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




A) Alcohols



B) Aldehydes



C) Halogens



D) Surfactants



E) Quanternary ammonium compounds



F) Phenols and Phenolic compound


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
A.


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,tub
erculocidal 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




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 .



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

 The

need for gloving

 The

practices of gloving not only
provides protection to dentist but also
to the patient




For eg:Dentist
treats

dentist contracts
herpes…herpes
whitlox

patient with herpes simplex
to patients treated in future








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




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


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.








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




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


 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.








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.








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 of
Orthodontic Arch wires




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

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



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.







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

Leader in continuing dental education


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

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (11)

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

Similar to Acute radiation syndrome /certified fixed orthodontic courses by Indian dental academy (20)

More from Indian dental academy

More from Indian dental academy (20)

Recently uploaded

Recently uploaded (20)

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

Editor's Notes