lab 1- prostho ii

7/29/2019 Lab 1- Prostho II

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1st

lab of prosthodontics

Salam bataineh

3esam al- 3alam

10-14 2 2013


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prosto lab 1 ""

~~ Partial denture ~~

This semester we have 12 week absence without excuse allowed for 2

section . on the lab please always wear ur lab coat, name tags & bring all

ur instrument.

* fabrication of complete denture :

Just to remind you on complete denture steps we need clinical & lab

procedures :

.1- history examination

2- take a primary impression by using impression compound,

alginate & butty silicon by stock tray on appropriate size for

patient.

3-study cast made by plaster "gypsum type 2".

4-individual tray , or called (custom or especial tray).

5-secondry or final impression made by : { ZOE , plaster ,

elastomeric impression material like condensation silicon

polyether [ a specific material on dentistry that made to be

work on wet environment but its expensive ] & polysulfide ,

impression plaster " gypsum type 1 " its accurate but rigid

material we can solve this problem by adding water to matrial

after it set to take it out from the tray or teeth if it stick on

the undercut for example } .

6-border molding by { green stick or impression compound }

they are two material different on color but mainly they differ

by fusing temperature mean at temp. where the material


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become soft so we can mix green stick with impression

compound .

Note** these materials are rigid or elastic, some of them set

by heat(thermoplastic) others by chemical reaction. But

especial material needed for some cases like patient with

undercuts so I must use a material go & set under them also be

flexible that I can remove like alginate or butty silicon which

set chemically but I am a student & I make a lot of mistakes so

I need a material that can be reused like thermoplastic

material "impression compound" & so on

7-secondry or master cast poured by using dental stone

"gypsum type 3 "

8-base plate + occlusal rim ( wax rim ) = record block

9-teeth selection & mounting the upper & lower cast in the

articulator according to jaw relationship then teeth sitting

10-try in stage to make sure of esthetic, function, phonetics,

occlusion

11- fabrication ( dewaxing, packing, deflasking, finishing &

polishing ) / insertion / recall visit

**these steps need about five to seven clinical visits

Partial denture :

Patients with 1 or 2 missing teeth or with one remaining

tooth for example all need something like dentures but bcz of

teeth present on mouth it called partial denture as you know

we have temporary(interim) or permanent(definitive) & they

become in different designs according to the missing teeth onthe jaws .


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-we have to follow same sequence of complete denture but you

can avoid doing some steps like on patient with one central

incisor missing on upper jaw no need for secondary impression

bcz it will be same to primary impression bcz on central incisorI am not worry about sulcus & no need for border molding !!

also no need for all jaw records exactly like in complete

denture or tray in stage for example so here I can make a

partial denture on one or two visit ~~ but on class I mod 1 in a

patient with two canine for example all steps needed.

** so steps for partial denture depend on remaining teethstructure

*1* here in partial denture we have some extra steps just on

doing the metal frame we will learn about them later.

*2* undercuts [ every patient with teeth have undercuts ]

-Note: so elastomers used on primary & secondary impression

but on the case we mention before who have just two caninesimpression compound can be used under tissue & elastomers

under canines on same tray !!

*3* in the lab before possessing we have to make clasp

[stainless steal orthodontic wire with 0.7 0.8 diameter]

Some differences b/t

partial & complete

denture :


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*4* impression is poured within minutes on stone instead of

plaster bcz its stronger or we can use 50% plster + 50% stone

- plaster used on primary cast :

[gypsum type 1] : 100g plaster need 60ml water

[gypsum type 2] : 100g plaster need 50ml water

-secondary cast :

[gypsum type 3 ] : 100g plaster need 30ml water

[gypsum type 4 ] : 100g plaster need 20ml water " called dental

stone "

The harder the gypsum product the less water used &

vise versa

how to make an impression ??

1. we have several types of trays for upper jaw which

include the palate & lower jaw which have tongue space

also there are perforated used to make the handling ofimpression material easier& nonperforated tray also

different sizes {we must leave about 5-7mm b/t teeth

& tray always}

2.we use utility wax if tray is under extended & usually

to make sharp angels on tray more soft by cover trayborder with it.


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3.fill tray with the material used alginate for example

mixed usually 3 scope enough for upper jaw & 2 scope

enough for lower jaw .

4. put alginate on occlusal surface of teeth before

entering tray on mouth.

5.tray inserted on patient mouth on lower jaw with

slight pressure then make slight movement for lip &

check to make functional movement of muscles &

frenums then rase the tongue then move mandible rt &

lf to record sublingual tissue.

** to accelerate sitting time we use hot water & to

decrease sitting time we use cold water never change

powder/water ratio.

6.remove the tray from the mouth on one movement.

7. for upper teeth we follow same steps but upper lip &

cheeks can be moved by dental mirror also its very

important to make sure that tray is extended beyond

the vibrating lines.

8.impression poured in stone as we Saied before &

when it set we make a base.

9.the cast is ready now to fabricate a removable

partial denture.


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Material used :

Last semester we talked about how complete dentures get

their retentive nature via many things one of them isperipheral seal, the case with partial dentures are different;

we cant have a peripheral seal in them and the reason behind

this is that in complete dentures the borders (flanges) go all

the way from suclus to suclus and to the post-dam area so air

cant escape.

In partial dentures the need of having wires or clips are to

create a seal to the denture, the company provides us with

wires in these forms.

We need to use specialized tools to bend these wires, they are

called Orthodontic Pliers. Orthodontists have many designs

for these pliers if not hundreds , each design to accommodate

each function .

What characterizes the pliers are the geometric shape of the

peaks, we have conical shape , pyramidal and triangular and

many other shapes . Sometimes we have three peaks,

sometimes we have peaks of the same shape ( e.g. two peaks ,

two triangular . ) sometimes we have them different from each

other ( one conical and one triangular ) and so on , so there are

lots of shapes to accommodate the need to make the designyou want .


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However the most common types of pliers we use in dentistry

are actually two: Loop forming Pliersand Adams Universal

Pliers(named after the dentist who made it; Philip Adam).

During this semester we are going to work with the first one;

the loop forming wires but in the next year we will be working

with Adams pliers during orthodontic training.

Before we start using the loop forming pliers we have to know

how they work, looking at their peaks you can notice that one

of the peaks is sharp and one is conical. If I bend the wire

toward the sharp edge Ill get a sharp bend depending on how

much force you applied. Also if you bend toward the conical

edge Ill get a curve (loop) depending on how much force you

applied.

Adams pliers (two pyramidal peaks shape) produces a right

angle bend which is much easier to do with this tool than with

the loop forming pliers.

Depending on where you put the wire: down at the junction or

toward the tip, how acute the curve is or how wide the curve is

the wire will be affected. If I put it at the tip Ill have a

bigger curve than if I put it at the junction down.

In orthodontics they make a 360 loop (spiral) curve, but in

Prosthodontics we dont do that do you know why? In

orthodontics they make these spirals to make springs in order

to make teeth a little mobile when applying the orthodontic

treatment. In Prosthodontics we dont want teeth to move we

want them to be firm. So each one has its own objective.


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When you cut the wires without paying attention to a proper

way the wire might bounces off and hit your eye or cause

permanent injury, you have to either cover the both ends or

point the wire under the table ( or your lab coat ) so no one willget hurt . The wires themselves they have a diameter of 0.7-

0.8, they are made out of stainless-steel

Done by: salam AL-bateineh

lab 1- prostho ii

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