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Rmz Rabadi
Layla Abu-Nabaa
4-7-2013
Part 1 : Alginate impression
2
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The art of making good alginate
impression
Before you start
We took this topic before so doctor Layla thinks that we are
suppose to know every thing about it by now ,,, and she'll only
give us what she thinks is new , anyway there was were no slides
for this lecture only two videos loaded on e-learning if you like to
take a look on them
Every single information in the videos will be here
I also took what I saw important from 2009's slides which were
given by doctor essam ,, and this will be enoughhopefully-
SO let us start
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Alginate falls in the ELASTIC ACQUOES HYDROCOLLOID type of
impression material.
Most widely used impression material
Indications
study models
removable partial dentures
Examples
Hydrogum (Zhermack)
Jeltrate (Dentsply/Caulk)
Coe Alginate (GC America)
Advantages
Inexpensive
Easy to use
Hydrophilic : displace moisture, blood, fluids
Stock trays
Disadvantages
Tears easily
Dimensionally unstable
immediate pour
single cast
Lower detail reproduction
than non-aqueous elastomeric
impression materials
unacceptable for fixed pros
High permanent deformation
Difficult to disinfect
Very popular choice Especially effective if there are lots of soft tissue
undercuts and/or teeth with different axial alignments
Cost effective and setting time is ideal
Composition
1- Sodium alginate
salt of alginic acid : mucous extraction of
seaweed (algae)
2- Calcium sulfate : reactor
3- Tri-sodium phosphate : retarder
4- Filler
5-Potassium fluoride : improves gypsum surface
Handling the Material:
1. Pre-measure material do not take containers to
your operatory. Do not handle containers with
contaminated gloves/hands. This makes infection
control easier.
2. Do not leave containers open in a humid
environment - humidity and high temperatures can
cause deterioration of the powder.
3. Do not mix in a bowl contaminated with dental stone -
gypsum can cause acceleration of the alginate. Conversely
alginate contamination of a bowl used to mix stone can
diminish the strength of the cast or model produced.
Keep separate bowls and spatulas for alginate and
stone.
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More easily removed from the stone cast than nonaqueous
elastomeric impression materials
Patient Preparations
Instructions to patient Relax lips, tongue, and cheeks
Advise patient that you will ask them to lift their tongue
Ask patient to concentrate on breathing through nose.
Review the procedure with the patient. (practice with a dry run)
Block out large embrasures and inter-proximal spaces to prevent
tearing of the impression material on removal
PREPARING ALGINATES ( all the information that was
mentioned in the video about this topic are included here )
Remember always to wear a mask to filter all the dust particleswhen using alginate powder since it is not healthy to breath any
(studies have found evidence of pulmonary hypersensitivity to
seaweed dust in force, and evidence of precipitating antibody to
sodium alginate and seaweed extracts in the serum of people
dealing with alginate dust )
Alginate powder come in two sets :
- Regular set : creamy in color , jells in 3-4 mins
- Fast set : pink In color , jells in 1-2 mins
Shake the container well before using the material to remix the
heavier components with the lighter ones (homogenizing the
material) resulting In a proper amount of the material in each
scoop .
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Prepare the materials you need with clean hands Temple the closed alginate container as mentioned before
Fill a scoop and tap it firmly until the powder is condensed
Put the maxillary 3 scoops in one bowel and the 2 scoops for
the mandible in another one
Add water to one of the bowels (which you like to take the
impression with it first )
Gently start mixing powder with water until the powder is
completely wet
Now the mixing action become more aggressive . use the blade
of the spatula to push alginate against the side of the bowel ,
this is called stropping .
Mixture can be held in one place and stropped side to side or it
can be moved around inside the bowel and the bowel is rotated
with the other hand
Aggressive spatulating continues until smooth creamy mixtureis obtained , which takes about 30 seconds ( fast set alginate
requires 45 second of mixing for a creamy consistency )
The mixture should not contain grains
Gather alginate on the spatula and press into the maxillary tray
from posterior , while mandibular tray must be loaded from
both sides allowing the alginate to meat at the middle
Try to avoid air bubbles while loading
Smooth the alginate with your wet figure creating an
indentation with your figure to help orient the tray when
seating it into the pt's mouth .
Now you are ready to take an impression
Preparations :
Measuring by weight is more accurate than by volume, but not
practical in clinic Therefore, we used measurement by volume in
the clinic
Ratio is
1 scoop powder : 1 measure water
For the maxilla :it needs 3 scoops of powder with 3 measures of water
For the mandible :
it needs 2 scoops of powder with 2 measures of water
Water measures are taken in room temperature since :
- Warm water will accelerate the set of alginate
- Cold water will retard it
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Selection of a Stock Tray ( all the information that wasmentioned in the video about this topic are included here )
- There are two tray types you can use when taking alginate
compounds :
Disposable plastic trays :
-Must be coated with adhesives to prevent its separation
from alginate especially when it contain no or fewperforations .
Metal trays :
- metal trays have a rim locked edges and many
perforations that prevent the separation of the alginate
from the tray when removing from patient's mouth .
- can be sterilized .
- no need for adhesives to be used (adhesives cannot be
cleaned) .
- When estimating the size of the tray that :
you'll use a barrier must be used on the deposable trays to
insure that it will not be contaminated .
metal trays can be sterilized so they do not need a barrier .
Make sure that the space between the tissue and the tray is3-6 mm .
- Impression trays come in small , medium and large sizes
- If the tray needs to be extended distally you can use beading wax
to build it up .
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- How to check the fitness of the mandibular tray ?? ( these
directions are for right handed clinicians left handed clinicians
must reverse these directions ) :
Stand at 8 o'clock position .
Hold the handle of the tray with your right hand and turnit over.
Retract the right check with the index finger of your left
hand .
Hold the tray sideways and insert it using the side of the
tray to retract the left cheek.
Rotate the tray in the mouth until it is centered.
Left the front of the tray up and visually inspect that the
alveolar ridges clear the tray .ask the patient if the tray
feels comfortable .
- How to check the fitness of the maxillary tray ?? ( these
directions are for right handed clinicians left handed clinicians
must reverse these directions ) :
Stand at 8 o'clock position . The insertion of the tray is the same as for the
mandibular one .
When the maxillary tray is in the mouth lower the
front of the tray to make sure it clears the alveolar
ridge .
Ask the patient if it feels comfortable .
- After finishing checking the trays ask the patient to rinse with full
strength antimicrobial wash for 30 seconds .
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Taking mandibular impression ( all the information that
was mentioned in the video about this topic are included here )
- Before inserting the trays, wipe some
excess alginate onto the occlusal
surfaces of teeth, deep undercuts or
areas which may trap bubbles (deep
palatal vault or lower labial sulcus)
- The right handed clinicians stand in
the 8 o'clock position , left handed
must reverse directions
- Raise the chair so you won't have to bend.- Set the patient upright .
- Hold the tray handle with your right hand then turn it over .
- Retract the right cheek and hold the tray sideways and insert it while rotating it
into the mouth until it is centered .
- Seat the tray gently over the teeth and soft tissues from posterior to anterior .
- Immediately muscle trim from the impression by bringing the patient's lower lip
up over the edge .
- Instruct the patient to left up their tongues upward and forward and relax it .
- Hold the tray into the patients mouth until the alginate feels rubbery and does
not stick to your fingers
- The setting time of the alginate using room temperature water is 2 mins and 30
seconds from the start of the mixing .
- Once the material has set , break the seal with one figure in the left vestibule in
the patients oral cavity .
- Snap tray quickly to minimize distortion .- Remove the tray by rotating it out of the oral cavity .
- Ask the patient to rinse out excess alginate
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- After removing both trays from the patient's mouth , give him a towel and a mirror to
wipe out excess alginate from the skin .
- Rinse the impression under running water and spray it with disinfectant ( it is
important not to soak the impression in disinfectant liquid due to the likelihood of
imbibitions .
- After 10 mins of contacting with the disinfectant rinse the impression before pouring
it with stone , it is recommended to pour the impression as soon as possible as
distortion increases due to delay pouring and evaporation .
- Wrap it in a paper towel that has been wetted and let set in a bag to
maintain 100% humidity .
Problem solving
You are treating a patient and preparing him for a partial denture prosthesis.
He told you he has a bad gag reflex which had stopped him from finishing the
treatment with another doctor. What are you going to do differently to take a
successful impression.?
Exaggerated gag reflex can frustrate both the patient and the dentist. It
can also compromise the treatment plan.
Its effective management is based on experience with combinations of
clinical techniques, prosthodontic management, medication, and
psychologist referral, or a specialist referral.
Some simple measures that usually works:
Reassurance and kind handling.
Upright position of the patient.
Avoid overloading the tray.
Spray some local anesthesia on the soft palate
Distract patients mind talking, raising one foot etc.
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=> Care of Alginate Impression
Should not be exposed to air (dehydration).
Should not be immersed in water for too long (imbibition).
Should be stored in a humid atmosphere by placing in a 100%
humidity humidor device or wrapping in a damp paper towel in
a sealed (zip-lock) plastic bag
Should be poured immediately, with delay not to exceed hour.
Support impression by handle or tray until cast poured
What is the difference between the following terms ??
Imbibition : distortion by water absorbtion
Syneresis : loss of water and shrinkage distortion.
Detergent : is a surfactant or a mixture of surfactants with "cleaning properties
in dilute solutions , removes dirt,especially from the surface of things
Disinfectant : are substances that are applied to non-living objects to
destroy microorganisms that are living on the objects.[1]Disinfection does notnecessarily kill all microorganisms, especially resistant bacterial spores; it is less
effective than sterilisation, which is an extreme physical and/or chemical process
that kills all types of life.[1]Disinfectants are different from otherantimicrobial
agents such as antibiotics, which destroy microorganisms within the body,
and antiseptics, which destroy microorganisms on living tissue.
Sterilization :is a term referring to any process that eliminates (removes) or
kills all forms of microbial life, including transmissible agents (such
as fungi, bacteria, viruses, spore forms, etc.) present on a surface, contained ina fluid, in medication, or in a compound such as biological culture
media.[1][2]Sterilization can be achieved by
applying heat, chemicals, irradiation, high pressure,
Asepsis : is the state of being free from disease-causing contaminants (such
as bacteria, viruses, fungi, and parasites) or, preventing contact with
microorganisms. The term asepsis often refers to those practices used to
promote or induce asepsis in an operative field in surgery ormedicine to
preventinfection. Ideally, a surgical field is "sterile," meaning it is free of allbiological contaminants, not just those that can cause disease, putrefaction, or
fermentation, but that is a situation that is difficult to attain, especially given the
patient is often a source of infectious agents. Therefore, there is no current
method to safely eliminate all of the patients' contaminants without causing
http://en.wikipedia.org/wiki/Surfactanthttps://en.wikipedia.org/wiki/Microorganismshttps://en.wikipedia.org/wiki/Disinfectant#cite_note-cdc-1https://en.wikipedia.org/wiki/Disinfectant#cite_note-cdc-1https://en.wikipedia.org/wiki/Disinfectant#cite_note-cdc-1https://en.wikipedia.org/wiki/Endosporehttps://en.wikipedia.org/wiki/Sterilization_(microbiology)https://en.wikipedia.org/wiki/Disinfectant#cite_note-cdc-1https://en.wikipedia.org/wiki/Disinfectant#cite_note-cdc-1https://en.wikipedia.org/wiki/Antimicrobial_agenthttps://en.wikipedia.org/wiki/Antimicrobial_agenthttps://en.wikipedia.org/wiki/Antibiotichttps://en.wikipedia.org/wiki/Antiseptichttps://en.wikipedia.org/wiki/Biological_tissuehttp://en.wikipedia.org/wiki/Fungihttp://en.wikipedia.org/wiki/Bacteriahttp://en.wikipedia.org/wiki/Virushttp://en.wikipedia.org/wiki/Growth_mediumhttp://en.wikipedia.org/wiki/Growth_mediumhttp://en.wikipedia.org/wiki/Sterilization_(microbiology)#cite_note-1http://en.wikipedia.org/wiki/Sterilization_(microbiology)#cite_note-1http://en.wikipedia.org/wiki/Sterilization_(microbiology)#cite_note-1http://en.wikipedia.org/wiki/Heathttp://en.wikipedia.org/wiki/Chemicalhttp://en.wikipedia.org/wiki/Irradiationhttp://en.wikipedia.org/wiki/High_pressure_food_preservationhttp://en.wikipedia.org/wiki/Bacteriahttp://en.wikipedia.org/wiki/Virushttp://en.wikipedia.org/wiki/Fungihttp://en.wikipedia.org/wiki/Parasitismhttp://en.wikipedia.org/wiki/Parasitismhttp://en.wikipedia.org/wiki/Surgeryhttp://en.wikipedia.org/wiki/Medicinehttp://en.wikipedia.org/wiki/Infectionhttp://en.wikipedia.org/wiki/Sterilization_(microbiology)http://en.wikipedia.org/wiki/Sterilization_(microbiology)http://en.wikipedia.org/wiki/Infectionhttp://en.wikipedia.org/wiki/Medicinehttp://en.wikipedia.org/wiki/Surgeryhttp://en.wikipedia.org/wiki/Parasitismhttp://en.wikipedia.org/wiki/Fungihttp://en.wikipedia.org/wiki/Virushttp://en.wikipedia.org/wiki/Bacteriahttp://en.wikipedia.org/wiki/High_pressure_food_preservationhttp://en.wikipedia.org/wiki/Irradiationhttp://en.wikipedia.org/wiki/Chemicalhttp://en.wikipedia.org/wiki/Heathttp://en.wikipedia.org/wiki/Sterilization_(microbiology)#cite_note-1http://en.wikipedia.org/wiki/Sterilization_(microbiology)#cite_note-1http://en.wikipedia.org/wiki/Growth_mediumhttp://en.wikipedia.org/wiki/Growth_mediumhttp://en.wikipedia.org/wiki/Virushttp://en.wikipedia.org/wiki/Bacteriahttp://en.wikipedia.org/wiki/Fungihttps://en.wikipedia.org/wiki/Biological_tissuehttps://en.wikipedia.org/wiki/Antiseptichttps://en.wikipedia.org/wiki/Antibiotichttps://en.wikipedia.org/wiki/Antimicrobial_agenthttps://en.wikipedia.org/wiki/Antimicrobial_agenthttps://en.wikipedia.org/wiki/Disinfectant#cite_note-cdc-1https://en.wikipedia.org/wiki/Sterilization_(microbiology)https://en.wikipedia.org/wiki/Endosporehttps://en.wikipedia.org/wiki/Disinfectant#cite_note-cdc-1https://en.wikipedia.org/wiki/Microorganismshttp://en.wikipedia.org/wiki/Surfactant7/28/2019 Prostho III Lec-2- Part -1- Alginate
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significant tissue damage. However, elimination of infection is the goal of
asepsis, not sterility.
Mixing time : the time to achieve a predefined level of homogeneity of a flow
tracer in a mixing vessel
setting time : The length of time that a resin or adhesive must be
subjected to heat or pressure or chemical reaction to cause them toset, that is, harden, gel, or cure.
border molding : the shaping of an impression material by the manipulation or
action of the tissues to determine the denture border position.
border extension of tray : extend borders of the tray if needed.
Extension should be made only to provide coverage of critical
anatomy, not for the purpose of displacing or distorting the vestibular
tissues, which should be registered accurately to obtain a peripheral
seal on a denture.
The Happy EndAm really sorry for any shortage , but there was nothing to refer to as a reference forthis lecture 10 hours of continues working hope you like it ,,, Enjoy