Dark room procedure/ dental implant courses

INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

 Film processing
 Composition of developer solution
 Composition of fixer solution
 Dark room equipments
 Safe lighting
 Practical processing methods
› Manual
› Automatic
› Self Developing Film

 The sequence of events required to convert the
invisible latent image, contained in the sensitized
film emulsion, into the visible, permanent
radiographic image
 The purpose of film processing is two fold
› To convert the latent a image (invisible) image on
the film into a visible image
› To preserve the visible image that it is permanent
and dose not disappear from the dental
radiograph www.indiandentalacademy.com

Indian Dental academy
• www.indiandentalacademy.com
• Leader continuing dental education
• Offer both online and offline dental courses

 Silver halide crystals in the emulsion absorb x-radiation
during x-ray exposure and store the energy from the
radiation, which forms a pattern and creates an invisible
image within emulsion on the exposed film. This is called as
Latent Image

Iodide ion
Bromide ion
Silver ion
Interstitial Ag ion
Sensitivity site
Silver bromide crystal in the emulsion of X-ray film contains mostly Ag+
and Br
-
ions with traces of I-
ions in a cubical crystal lattice. Free interstitial Ag+
ions and
areas of trace chemicals (Allyl thiocarbamide) serves as sensitivity sites before
exposure.

 During film processing, Selective
reduction of the exposed silver halide
crystals occurs

Iodide ion
Bromide ion
Silver ion
Interstitial Ag ion
Bromine atom
Sensitivity site
Exposure of the crystal to an X-ray beam results in the release of electrons (e-
)
by interaction with Br ions. Br -
Br + e-
. Recoil electrons have
sufficient kinetic energy to move in crystal. Gets entrapped in sensitivity sites
and impart negative charge to this site
e-
Photon
Gelatin

_
Iodide ion
Bromide ion
Silver ion
Interstitial Ag ion
Bromine atom
Sensitivity site
Free interstitial Ag+
ions are attracted towards the negatively charged
sensitivity site

Iodide ion
Bromide ion
Silver ion
Interstitial Ag ion
Bromine atom
Silver atom
Sensitivity site
When interstitial Ag+
ions reach the sensitivity site, they acquire an
electron and become Ag atom (Ag+
+ e-
Ag). This Ag atoms
constitute the sensitivity.

1.IMMERSION OF EXPOSED FILM IN DEVELOPER
› Developer distinguishes between exposed and
unexposed silver halide crystals
› Initiates chemical reaction that reduces the exposed
silver halide crystals into the black metallic silver
and creates dark or black areas on the film.
› At the same time, the unexposed silver halide
crystals remain virtually unaffected by the developer
solution

2. WASHING
 The film is washed in water to
remove residual developer
solution

3. IMMERSION IN FIXING
SOLUTION
 Fixer removes the unexposed
silver halide crystals and creates
white or clear areas on the
radiograph meanwhile the black
metallic silver are not removed and
remains on the film

4. WASHING
 The film is washed through in
running water to remove residual
fixer solution
5. DRYING AND MOUNTING FOR VIEW

 Made up of black, white and grey areas

PROCEDURE

 Developer – reducing agent
- purpose is to convert exposed silver halide crystals in
to metallic silver grains
HYDROQUINONE – PARAHYDROXY BENZENE
› Generates the black tones and
› Sharp contrast of radiographic image
› Temperature sensitive
› Inactive below 60o
F
› Very active above 80o
F
› Optimal temperature is 68o
F

ELON- MONOMETHYL PARA AMINOPHENOL SULPHATE
› Generates many shades of grey
› Not temperature sensitive
 Widely used in combination
 If used individually
ELON - produce a film that appeared gray with
indistinct contrast
HYDROQUINONE – produce a film that appeared black
and white

 SODIUM SULPHITE
› antioxidant
› Has greater affinity for oxygen and
› Protect the developer from being oxidized by atmospheric
oxygen
› Also combines with the brown oxidized developer to
produces a colors
› Helps extend the useful life of hydroquinone and elon

 The developer agent are active only in alkaline –high
pH – medium (pH - 11)
 To maintain this condition, they contain alkali which
serves as an activator (accelerator)
 SODIUM CARBONATE, SODIUM HYDROXIDE AND
SOMETIMES SODIUM METABORATE, SODIUM
TETRABORATE
 When developing agents reduces silver halide
granules H+ produced which causes fall in pH and
depress the reduction of silver that is slow
developing process, therefore activator is used to
fasten the process
 Also serve to soften the gelatin so that developer
agent can diffuse more rapidly into this emulsionwww.indiandentalacademy.com

 POTASSIUM BROMIDE
 Added because bromide is a product of reduction of
silver halide crystals and added bromide serves to
depress the reduction by common ion effect
 Although it dose depress the reduction of both the
exposed and unexposed crystals, it is much more
effective in depressing the reduction of unexposed
crystals, so as a consequence acts as an ANTIFOG
AGENT

 After developing film is to be rinsed in water for 15-
20 seconds before they are placed in the fixer
 This rinse will dilute the development process
 Also removes alkali activator thus preventing
neutralization of acid fixer

 Function is to remove the unexposed silver halide crystals
from the emulsion
 Presence of unexposed crystal cause the film to be opaque if
not removed will cause the film to be obscured and non
diagnostic
 The other function of fixer is to hardened the emulsion (on
the film)

 Fixing agent
 Aqueous solution of SODIUM THIOSULPHATE or
AMMONIUM THIO SULPHATE
 Function is to remove the unexposed and
underdeveloped silver halide crystals from the film
emulsion
 The chemicals clears the film so that the black image
produced by the developer become readily
distinguished

ACETIC ACID OR SULPHURIC ACID
 The purpose is to neutralizes the alkaline developers
 Also produces necessary acidic environment for fixing

 SODIUM SULPHITE
 To prevent chemical deterioration of the fixing
agent

 POTASSIUM ALUM
 To harden and shrink the gelatin in the film
emulsion after it has been softened by the
accelerator in developer solution
 Shortens the drying time

 Should be washed in a sufficient flow of
water for an adequate time to assure
removed of all processing solution
 Washing efficiency is influenced by water
temperature and decreases rapidly below 60o
F

 Primary function is to provide a completely darkened
environments, where x-ray film can handled and processed
to produces diagnostic radiograph

 Conveniently located
 Of adequate size (16-20 sq feet)
 Equipped with correct lighting arranged with ample
work space and storage
 Temperature and humidity controlled
 Room should be well ventilated
 Light proof
 Door should have locks to prevent accidental
opening

 Location must be convenient and near to the area
where x-ray units are installed
 Large enough to accommodate film processing
equipments and to allow ample working space
 Measured at least 16-20 square feet

 Room must be completely dark and must exclude all
visible white light
 LIGHT TIGHT – completely dark room
 LIGHT LEAKS –light leaks into dark room
- May cause film fog
 Tow types of lighting
› Room lighting
› Safe lighting

 Incandescent room lighting is required for
procedure not associated with the act of processing
film.
 Required for other tasks like cleaning, stocking
materials mixing chemicals

 Special type of light that is used to provide illumination in the
dark room during processing
 Low intensity light composed of long wave lengths in the red –
orange portion of visible light spectrum
 Dose not rapidly affect on open film ,but permits one to see
well enough to work
 Typically consist of a lamp equipped with a low wattage (71
/2 or
16w) and a safe light fitters

 Safe light filter removes short wavelength in blue green portion of
visible light spectrum that are responsible for exposure or
damaging the film
 Safe light filter permits passage of light in the red orange range
 Most films hare reduced sensitivity to this red orange range and
are not affected by minimal exposure
 It is necessary to maintain an adeqquate safelight film handling
time to a
Minimum Distance – 4 feet / 1.2 meters
Time 2-3 minutes (Handling)

1. MANUAL OR WET PROCESSING
2. AUTOMATIC PROCESSING
3. USING SELF DEVELOPING A FILM

 Carried out in dark rooms
 General requirements are
› Absolute light tightness
› Adequate working space
› Adequate ventilation
› Adequate washing facilities
› Adequate film storage facilities
› Safe light - 1.2 m from work
25 w bulbs / filters

 PROCESSING EQUIPMENTS
› Tanks containing various solutions
› Thermometers
› Immersion heater
› Accurate timer
› Film hangers

 PROCESSING CYCLE
› The exposed film packet is unwrapped and film
clipped on to a hanger
› The film is immersed in developer and agitated
several times in the solution to remove air bubbles
and left for 5 min at 20o
C.
› The residual developer is rinsed off in water for 10
seconds
› The films is immersed in fixer for about 8-10 min
› The film is allowed to dry in a just free atmosphere

 Processing is carried out automatically by a machine
 Several automatic processors are available which are designed
to carryout the film through the complete cycle usually by a
system of rollers
 The cycle same as for manual processing except that the rollers
squeeze off any excess developing solution before passing the
film onto the fixer, eliminating the need for the water wash
between these two solutions.

ADVANTAGES
 Time saving –Dry films are produced in
5 min
 Need of dark room is eliminated
 Controlled standardized processing conditions are
easy to maintain
 Chemicals can be replenished automatically by
some mechanics

DISADVANTAGES
 Strict maintenance and regular cleaning is
must
 Equipment is expensive
 Smalls machines cannot process large
extraoral film

 An alternative to manual processing
 X-ray film is presented in a special sachet containing developer
and fixer
 Following exposure, developer tab is pulled, releasing developer
solution which milked down towards the film and messaged
around it
 After 15 seconds the fixer tab is pulled , to release fixer which is
also milked down
 After fixing the used chemical are discharged , them film is
rinsed in water for 10 min and dried

ADVANTAGES
 No dark room or processing facilities are
needed
 Time saving –the final radiograph is ready
in about 2-3 mints

DISADVANTAGES
› Poor overall image quantity
› Image deteriorates rapidly with time
› No lead foil inside the film packet
› Film packet is very flexible and easily bent
› Difficult to use in positioning holder
› Relatively expensive
 A rigid, radiographs plastic backing support tray can
be made, which helps to reduce the problems of
flexibility and lack of lead hold

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