Prostho III Lec-2- Part -1- Alginate

7/28/2019 Prostho III Lec-2- Part -1- Alginate

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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/Surfactant


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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

Documents

Prostho III Lec-2- Part -1- Alginate