Prosto Mid Lap

8/10/2019 Prosto Mid Lap

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Prosto mid lap

Primary impression

After the patient is examined clinically, radiographically,

intraorally and extraorally then we can say this patient is ready

for us to make him a denture

Q1 what are the steps that you do it in primary impression?

1 select impression material (compound or alginate )

2 select impression tray

3 prepare your tray

4 take the impression

5 disinfect your impression

6 deliver the material for the lab

steps?Q2 explain each step of the primary impression

Step 1: selecting impression material

We have 2 materials alginate and compound

** Alginate is used for the patients who has undercuts in the

residual ridge area

** Compound is regularly used in all patients

Step 2: selecting impression tray

Impression trays are classified into 3 categories depending on 3

things1

** Use (form): dentate or edentulous trays


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** Material type: metal or plastic

** Shape: perforated or not perforated

----- Edentulous trays look circular from the behind similar towhat patient has (cross section from behind is circular)

----- Dentate tray looks high with space for teeth so it is

vertically high with deep sulcus (cross section from behind is

square shape)

Q.A what will happen if you took an impression using

used??n that should bedifferent type of tray tha

If you took an impression using an edentulous tray for dentate

patient it won't fit

But if you took an impression for edentioulus patient using a

dentate tray then u will face 2 problems

1 for sulcus depth it will be beyond it and it will lead totraumating the patient

2 vertical height problem that will make u use more impression

material than required leaving u with time and expense

problems

2 there is 2 other things that are important to be determined

and they are (size of the tray + retention method)

** Size of tray: it is done inside the patient mouth for the upper

and the lower trays

?of the traycheckQ.B why we always do size

1 the shape and the size of the ridge is different between

patients and we can't always find what we call it the ideal case


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2 there is no tray that fits all patients

tray?upperQ.C how to determine the size of the

1 place tray from front to back

2 look at the tray while you are tilting it

3 if it was large you will find that post. Area is hitting the cheek

distorting the tissue and ant. Area will be going outside the lip

4 if it was small put it at the hamular notch area then you will

find that the flanges (border of the tray) is either hitting thesulcus tissue of the ridge from borders or from anterior

** remember we need it 6 to 7 mm extra only for compound

and the flanges from post. Area with no space to record

5 if it was fit it will be suitable with space all around the ridge

with no hitting for the tissue

lower?from thediffersisQ.D what upper

It is the same but instead of placing it over the hamular notch it

will be on the retro molar pad and not only the cheeks will be

distributed the tongue will also distributed

startingQ3 what are the things that you should do it before

compound?primary impression withtaking

1 prepare your things

2 use hot water at 54-55 degree that it must be hot but

tolerable

3 use gose to prevent the stick of the compound to the rubber

bowel why? Coz when compound become hot it is wax it will

stick and damage the rubber bowel


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4 use 1 cake for the lower and 1.5 cake for the upper

impression using compound material?lowerQ4 how to take

1 spread the gose in the warm water

2 put the compound in the hot water

3 when it become easy to manipulate and played then it is

ready to be used coz it is thermal connection that soften/warm,

harden/cold

** The compound contain wax and filler which prevent it frombecoming liquid

4 make it in form of a ball and reput it foe evenly heating to

record everything properly

5 lengthen the ball in a tube form

6 spread it from the middle making the bulk of the material on

the sides

7 loads the material in the tray and the excess must be adapted

in the tray from the sides to the back

8 smooth the surface to avoid cresses (folds)

9 lengthen the compound from the lingual side due to presence

of lingual pouch that is deep and must be recorded correctly

10 make small grove that will help in recording the sulcus

11 reheat the compound while it is on the tray coz it become

hard due to manipulating by resoaking it in the hot water to

become soft again to record everything


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12 spread the cheeks while you are holding the tray to take the

impression

13 stand in front of the patient if it was for the lower and

behind the patient if it was for the upper

14 press firmly over the tray to record things till it set coz it is a

heat reaction not chemical reaction I can use water to increase

the setting time

15 ask the patient to move the tongue right and left to mold

the area under it and next to it (lingual area)

16 mold the material from the cheek and lip area from the

outside

17 snap removal of the tray to ensure no loss of details after it

is removed

18 check that these areas are recorded or if not redo the

impression and these areas are:

Sulcus must be cont all around / buccal and lingual freni /

lingual sulcus must be cont / lingual pouch must be in full depth

to take thelower processQ5 what upper differ from

impression?

It is similar but with difference in these points

1 position of stand

2 avoid any flow of the material by making excess away from

the post. Midline area coz we want to avoid gag reflex of the

patient


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3 make the excess reach the buccal pouch the deepest area to

be recorded

Q6 what are the things that you should take care about for

taking impression with alginate?

1 wear gloves

2 wear face masks coz alginate is a hazardous material it can

participate in your lungs

3 prepare the powder spoon and the dispensing spoon and the

dispensing cup

4 each scoop of powder must be with 1 unit of water

5 you will need adhesive spray for more retention

6 prepare the perforated tray wither it is metal or plastic coz it

will make tags that will also help in retention

alginate?Q7 how to take impression using

1spray the tray with the adhesive material and leave it till it dry

or it will act as a separator not as adhesive so wait till it become

tacky

2 avoid tearing or ripping off of the alginate by these things

** make sure that the tray is covering all the sides and ends

specially at disto buccal angle or distally coz it will cover the

ridge but the post area will not be covered so the alginate can

become from back and tear up when removing so we must add

length to post. Side


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** use utility wax to prevent alginate from going the patient

thought by extending the length of it

---- For lower trays extending the length is due to shortening in

the disto buccal angle area or distally due to ridge length

----for upper distobuccal angle +distal border +from the ant in

pre maxillary area

** place utility wax at the sites where we say to elongate the

border while taking the impression for deep sulcus

---- Lower areas are: buccal shelf +distal area + lingual pouch

area

---- Upper areas are: buccal pouch +distally if short +in vertical

way to prevent flowing + pre-maxillary area

3 mix alginate bag why? Coz the bag contain heavy and light

components and for the best results these components must

be mixed together

4 place 2 units of water in the rubber bowel with 2 scoops of

alginate (water always before powder to avoid air bubbles)

5 initial mixing which is circular mixing then squeeze the

material o the sides by figure 8 movement

**note that alginate color do change while mixing from pink to

yellow to orange (visual indicator for setting)

6 load the impression material from inside and smooth it with

water then take the impression

7 squeeze the tray while taking the impression till it sets


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** U can make sure that the material is set for both alginate

and compound by the finger nail test that will help u to do that

(((lower and upper impression for the alginate is the same but

the only thing that is different is the amount of alginate that is

used ((3 units in the upper)) ((2 units in the lower))))

8 after it set and we make sure it is set then we leave it for 1

min to maintain some strengthen in it

9 remove the tray by snap removal to increase the strength of

the unsupported areas

10 check for the features that we check for it in compound

(anatomical features)

11 wash the compound under water for 2 min to ensure that 90

% of the microbes have been removed

the coming steps are for both alginate andNow((((((((((

)))))))))difference)compound with slightly

12 we do the disinfection step

**it is done by low or medium ability solution

** Alginate disinfection: senarises will force us to use spray

methode to avoid expansion and losing dimensions

** Compound disinfection: soacking form due to propriety of

unchanging by the moisture

13 after the disinfection we must leave it for 10 min

14 wash the disinfectant


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15 move them to the lab in the most decent form meaning no

hitting them and smooth handling with good labeling to avoid

mixing with other impression

Q8 Why time is a bad factor for alginate and compound?

Coz it will let us lose the heat from the compound leading to

distortion and will lose the moisture of alginate

Q9 what is the best time to deliver the impression to the lab?

It must be delivered within 15 to 20 min and they must be

poured within 30 to 60 min

Q10 what is the ideal way to transport alginate and compound

to the lab?

Alginate: move in sealed bag with a water wet napkin in it to

avoid drying / put it in solid container box to avoid cracking it

Compound: wrapped it in a tissue / use hard box too

Q11 what you should do to the technician to know what you

want?

Fill a form that u asks in it for a special tray and you must write

in it these things:

Name of the patient / date/ requests that u want from the

technician / time of next appointment to get the delivery


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Primary cast

Now after we made the impression and send it to the lab the

primary cast that is the next step will be done

need?Q1 what are the instruments that we

Rubber bowel / spatula / plaster/ water /

cast?Q2 what are the steps to do the primary

1 washes the impression with water for 1 min to reduce the

microbial presence of infectious

2 draw the outline sulcus from ant. Line using special pencil

(independent pencil) coz it can copy itself in the cast when it is

poured

3 mix the material 45ml water and 100 ml of plaster

4 put the powder into liquid so liquid is first to avoid air

bubbles

5pour the mix on the vibrator to increase the flow and from

side to side

6 pour plaster step by step to avoid trapping gas and forming

bubbles and from ant to post

7cover the sulcus from all sides +uses excess material to make

the lumps (function as stand to maintain the base of the cast)

8 leave it to be set and dry (for initial time 30 min)

9 we add base after it set initially

** For upper we pour from ant to post but for the lower we

pour post to ant


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** remember always to add lumps

** Full set time is 24 hours

Q3 how to do the base of the primary cast?

1 mixing 35 ml of water with 100 g of plaster

2 water is reduced here to make it thick so we can form in base

shape

3 make the lumps huge one that stands for the base

4 cover the sides with plaster to avoid air bubbles formation

5 invert the impression over the base material

6 press it to cover the entire base with cast and smoothening

the base to have sufficient amount

7 maximum smooth is reached by wetting finger and roll it all

around

8 leave it for 1 hour to set before trimming

** In mixing be fast and press the materials to the side of the

rubber bowel to avoid any air bubbles formation

** be aware for the middle area of the lower where tongue

must be found is empty

it after making thedoQ4 what are the things that we need to

base?and thecast

1 check if there is any excess of plaster that run in the border

and remove it with wax knife to avoid fracture of plaster in land

area +easy removal


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2 separate the material and the tray so if it was alginate it was

stand for a full set 24 hours and it is hard and not easy to be

removed so you must soak it in water for 5 min and same for

compound but make it hot water

3 define the sulcus line on the cast to avoid removal of it while

trimming

4 trim the cast by a trimmer that contain a stone wheel which is

capable of removing plaster

5after trimming smooth the land area with a knife and wash it

** Things to be remembered:

1 removal of alginate tray require soaking for 5 min

2 removal of compound require soaking for 5 min in hot water

3 removals is done by snap shot except for the upper to avoid

any fracturing of recorded under cuts or if it was with teeth soremove the tray alone then remove the material alone

4hight of the base is 1.2 to 1.5 mm at the deepest sulcus point

5 highest of the base at the center is 1.5 to 2 mm

perfectly?how to trim your castQ5

1 to make the plaster removal more easier we should soak only

the base by water for 5 min so it become soft we dont soak the

anatomical area at all coz it will lead to lose of these anatomical

features that we want

2 make sure that while trimming the water is running coz if it

helps in: reducing the friction/ reduce heat / clean surface


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while cutting / increase cutting efficiency / lubricate the stone

wheel / preserve the life of the stone wheel

3 trim the post area first and preserve the hamular notch and

retro molar pad are and make it flat an parallel

4 trim sides by rotation of the cast and preserving the line

which is 1 to 2 mm external to the external sulcus line (land

area line)

cast?Q6 how the primary cast is considered to be an ideal

1 all anatomical parts must be included

2 cont. sulcus line all around

3 parallelism of occlusal plane with the floor

4 land area surrounded by the sulcus must be 1.5 to mm

5 vertical and lateral surfaces

6 accepted thickness at the deepest point 1.5 mm

Q7 what are the most common defects that we might face in

the primary cast formation?

1 thin cast ---- it will fracture

** Thinnest area in the upper is the palatal area

** Thinnest area in the lower is the lingual pouch area

** Always look at the deepest point and the thinnest areas

2 missing of sulcus (bad recording) bad impression --- not good

cast

3 missing some of anatomical areas due to over trimming


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4 thin margins --- no border --- easily fracture

5 missing all land area --- no trimming properly and no

recording properly

6bubbles in the base ---- plaster was added in a non cont way

7 thick and titled casts --- bad recording and the cast wasnt

parallel with the floor while trimming

8 v-shaped between cast and base ----- gap formation due to

absence of vertical filling

9 bubbles in anatomical surface --- bubble in the impression will

make it look like projection

10 thickness of lingual pouch---- lead to fracture if it was thin

coz there is thin base

11 excessive pouring---- it is very high from the sulcus coz it is

only 2to 3 mm above the sulcus in tongue area

12 loss of retro molar pad area or hamular notch area ---- over

trimming

13 missing anatomical feature ---- incorrect trimming and the

pouring was not on a vibrator and defects in the impression

((((((((Avoid these things to reach the ideal cast)))))))


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Special tray

The secondary tray is needed to get more accuracy using

prefabricated tray to make casts

tray?Q1 when do we really need to do special

1 for large or small jaws

2 when we do tumor surgery

tray?of the specialcharacteristicsQ2 what are the

1 made of light cured material or cold cured material

2 must fit on our primary cast that comes from patient mouth

3the tray fits one cast only so it fits one patient only

4 trays are formed from 2 things:

A body of the tray: cover the basal seat area that will be

covered by the denture

B handle: grip the part which dentist hold the tray from, it must

be inclined and away and no interfering with the lip

5 some perforation

6 finger rest: in order to maintain the pressure to avoid slipping

by saliva in patient mouth

7 trays will be either closely fit tray (no spacer or wholes) or

partial fit tray (relief wax spacer/ holes or specicific areas for

selective pressure teqnique

8 either we have full relief or partial relief trays

9 in all relief trays we have stoppers to prevent over seating ofthe tray


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**function of separator is separating between the tray and the

tissue

Q3 what are the relief areas in special tray?

1 complete relief: covers all the features from inside

2 partial relief: covers only areas that can't handle the pressure

**impression in the special tray is taken after the border

molding by ZOE

** If we dont have a spacer the ZOE will be pressed betweenthe tray and tissue leading to displace of tissue

** Mucostatic teqnique dont remove tissue from its place

**spacer in relife Areas lead to formation of mucostatic

condition and we avoid pressure

** We have in partial relief 2 things:

1 primary support area

2 relief area

**relief areas must not be compressed coz they won't tolerate

**histo features and they are:

1 we have bone ---- sub mucosa ---- mucosa

So when taking an impression without a spacer the areas that

can handle it for the upper jaw are (hard palate+ tuborisity +

slopes of the ridge ) for lower jaw (slopes of the ridge)

** now the press is called compression method and it compress

the tray with impression material with mucosa and sub mucosa


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and compact bone and the areas that can tolerate it are called

the primary support areas

**hard palate can with stand the pressure due to presence of

glandular tissue in the post. Area

2 we use the spacer to decrease the press over the impression

material and that is done by the stoppers and the areas that we

need to relief in the lower are (crest of the ridge + mental

foramina) but in the upper (crest of the ridge +incisive papilla

+ruage area +mid palatine raphe) these are called relief areas

locations?Q4 why I need to relief the areas in these

1 around the tuborisity if they are pulps and the undercuts and

the mid palatine raphe?

The reason is that the submocsa is not the same thickness as

other areas it is less so that will lead to traumatizing the

mucosa due to hard bone beneath it

2 incisive papilla area and mental foramina

The reason is the presence of bundles of nerves and blood

vessels

** take in considerationthe2nd because the mucosa and the

sub mucosa are normal but nerve will release tingle undernormal pressure but under extreme pressure it will be painful

and can't be tolerated

3 mid palatine raphe and knife edged ridge

The reason is the presence of the bone spacules that will lead

to traumatizing the mucosa by these bone projection

4 ruage area


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Reason of relieving this area coz it is rough and irregular that

will be squeezed under pressure and can't be tolerated

not?Q5 how the quality of bone play a role in relief or

If the bone was compact then it is more capable of

withstanding pressure coz it is more mineralized but if it was

spongy then it won't be able to tolerate and will resorp faster

than the compact bone leading to

1 losing of the height of the ridge

2 basal seat area is lost and that will lead to traumatizing the

patient under long term and it is found in these areas (teeth

areas in dentate patient = alveolar crest areas = crest of the

ridge)

spacer?Q6 what are the methods of placing

1 put the spacer then removes it before impression remove it

2 no spacer but perforation in relief areas

**mucostatic at relief areas

** Compress at support areas

tray?Q7 how to make the special

1draw the line in the deepest point in the sulcus (basal seat

area) covering all details for both upper and lower

2 draw the tray line away from your first line by 2 mm to 3mm

(it must meet with the first line in the post area only)

3 draw now the relief lines (spacer line) over these areas (mid

palatine raphe / ruage area / crest of the ridge without the


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tuborisity / canine eminence / crest of ridge) this line is away

from the 2nd

line

4 add stoppers in relief areas

5 if it was perforation then make circles over the relief areas we

mention

6 make the relief spacer using base plate wax coz it has known

thickness and even 1.3 to 1.5 mm

7 soften the base plate till it like a paper by slowly heating

(tempering) in and out to spread the heat

8 adapt the wax over the cast no pressing just spreading then

cut the excess of the wax and prepare the stoppers and remove

all the excess

9 adapt the material better but avoid pressing

10 use light cured material coz it is easier to be manipulatedand adapt it over the cast and the spacer

11 press using a carver in the deepest area in sulcus and

remove the excess that is over the land area

**for the perforated tray do the same but make the

perforation before you cure it

** To prevent the shrinkage of the acrylic we must place sthng

that prevent the curing of the palate area till we cure the tray

then we cure this area alone

**dont forget to do the stoppers


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12 take the excess and form the handle and make it proper and

dont make it hitting or bothering the lip so it dont push the lip

and record the sulcus

13 fuse it with tray before curing

14 support the handle by preventing any changes during curing

15 we add Vaseline to the surface to avoid air inhibiting areas

16 light cure is almost 3 min

** Light cure machine rotate to give the best result but we doanother curing after finishing for the fitting surface

17 start the trimming by acrylic bur so you can have smooth

surface so patient won't be injured so dont reduce the length

just round the border

**take care and handle the handpices in a proper way to avoid

injury

** leave the sharp border that will stick to green stick

18 put it on the cast and make sure it covers all


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Secondary impression

2ndry impression is very important coz it increase the accuracy

and we start taking it by making border molding then using ZOE

then boxing

molding?Q1 how to do border

1 we must make sure that the space is true inside the patient

mouth by checking the labial flange extension and frenum

clearance

2 the border must be shorter than patient sulcus if not trim it

till it become shorter

3 we use material called green stick for this procedure which is

similar to compound but with less filler in it so it runs at lower

temp and become ready to cover details

4 if we are using perforated trays then we must close these

perforation before doing border molding coz we need the best

suction we can get and that can't be done with these

perforations

5we need water to cool down the green stick coz different than

compound we use dry heat so we must avoid burning the

patient

6 saliva helps to avoid sticking which Vaseline compensate in

the lab

7 no sharp edges on the tray only rough edges

8 wash saliva from the tray to make the green stick adhere

9 adding are done section by section


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10 heating is done by tempering till it flow

11 the green stick when it is warmed it can stick to the border

of the tray but in case it cooled a little it can be placed but cant

stick which will lead to fracturing after placing

12 we then mold the green stick and remove any thing that

goes buccaly or lingually or labilay and we join it all together

and we do it in form of roll and elongate it and smoothening it

13 due to manipulation the green stick cooled down so we

must reheat it a little bit before we put it in patient mouth tomake sure it can record properly

14 we put it in warm water to cooled down so it dont injure

the patient

15 take the impression of the part we need and losing the sine

in the surface will indicate that I recorded the max depth of the

sulcus

16 in patient mouth I manipulate the tissue around and record

everything at working not resting position to mimic the

function of the lips and cheeks

17 we do it section by section

18 we continue doing all of these steps section by section till Ifinish the whole border

19we cool it with warm water not cold water coz it will lead to

losing of flexibility

** for the disto buccal angle of upper I make patient open

maximally and move mandible right and left so we can record

the area


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20 if we have bubbles or any problem in border molding we can

re do it easily

21 when recording freni we move the cheek front and back to

record them coz they are muscular

22 sometimes we lose some dimension from post. Of palate or

hamular notch area coz of acrylic curing so we can compensate

with the green stick

23 for hamular notch area we ask the patient to open wide to

record mandibular raphe moves

24 for post. Part of the palate we ask the patient either to

Solow or say ahhhh so that we make the soft palate moves and

record it

25 green stick adding is similar to all the areas except the post

part of the palate where I put it on the fitting surface due to

formation of glandular tissue so we do post dam in it (speciallyon the sides of the raphe)

26 we put on hamular notch and let the patient open wide and

move mandible right and left so coronoid prosess become so

close that I can record the width of the sulcus

27fitting surface on the hamular notch must not be covered

28 after finishing just reheat it and take the impression from

disto buccal to the other distobuccal

29 after finishing everything check for these areas:

1post palatal zone/ 2 buccal vestibular sulcus / hamular

frenum/ buccal frenum / ant. Frenum / ant .vestibular sulcus /

posterior zygomatic vestibular sulcus


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work?for the quality of yourcheckQ2 how to

By ensuring that u has a good border sealing that the tray won't

be easily removed when placed inside the patient mouth

Q3 what are the things you should take care of them when

stick?working with green

1 saliva act as Vaseline it stop the adherence of the green stick

2 always add the first layer of the green stick as an glue layer

then add the bulk of it above

3 in the lower I always ask the patient to whistle or to bring his

lips up and to the sides to record mylohyoid area

4 shining lost indicates that the deepest part of the sulcus has

been recorded

5 any excess on the buccal or labial areas must be removed

6 in the lower retro molar pad area we ask the patient to open

wide and move his mandible right and left to record the stretch

of masseter muscle and borders is recorded

7 add more green stick on retro molar pad area on fitting

surface to record all details

8retro molar pad area is compressible area coz it contain fatty

tissue and glandular tissue

9 record the lingual pouch area coz it is responsible for the

retention and it is deeper than the buccal area so we build it

vertically to make it easier then we ask the patient to open

maximammly and protrude tongue to the max so gloss

pharyngeal muscle work then ask him to Solow to activate the

deepest part of the lingual pouch so we record it perfectly


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10 lingual side of lower from 6 to 6 is where mylohyoid muscle

work, it can be molded by moving tongue right and left then

posteriorly so the main movement and reasons are:

1 protrude tongue = increase thickness of the material

2 left and right movement = reduce the sulcus depth

3 pushing the tongue toward the palate = recording ant. Area

ZOE?impression usingsecondaryQ4 how to take the

1 removes the spacer before using it

2 It is 2 pastes (base +catalysts) first they must be collected

then mixed together so they have similar layer

3 squeeze the material then spread it then gather it and keep

redoing it to become ready to spread on tray

4 spread ZOE on the tray, flow it to all surfaces with even

thickness all around

** It has good working time

5 seat the tray in place and press firmly from back to front so

we have less material excess post and make it go ant

6 we ask the patient to do all the movement as he do it in the

border molding to ensure everything is recorded correctly

7 material set is indicated b finger nail test

8 set inside the patient mouth is affected by heat and moisture

because the setting time will be reduced

9for the lower is similar to the upper but put more on the

lingual part and cover it good


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10 movement must be done inside the patient mouth again as

in border molding coz the sulcus will get back to rest and we

want it in working depth to record it

11 removal f the tray is easy inside the patient mouth

Now we will move to the last thing which is the boxing


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Study these carfully

Maxilla resorption

In here the resorbtion occur in these directions: backwardinwardupward

And that will leave us with a smaller maxilla

Anterior area resorbtion: resorbtion occur posteriorly so the

crest of ridge will go more posteriorly

Posterior area resorbtion: resorbtion occur inward so crest of the

ridge goes more medially and ridge become smaller in height so

it goes upward

** take in consideration the resorbtion rates in making the wax

rim coz u will be forced to do these things:

1 the center of the wax rim should be a little bit buccal to the

center of the ridge due to the position of the pre-extracted teeth

position

2 the wax rim is diverged interiorly to make a labial support and

it must be proclined and tip of wax rim must be at the beginning

of the land area of the cast (labial to the cast) and from posterior

it must be almost near the land area not direct on the land area

(little bit to the center of the ridge)

**VIP with age the resorbtion increase so we will need morewax rim facially

** Resorbtion after extraction happens in the area of bone

projection resembling the socket of the teeth and we should take

care about these things:

1 dont do a denture after extraction immediately coz there is no

resorbtion yet


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2 make a denture after 3-6 months of extraction coz it is the

highest rate of resorbtion period then from 6 months to 1 year it

will slow but it will never ever stop

3 reason of resorbtion is physiological coz we have alveolar

bone which support the teeth once the teeth are lost then we

dont want the bone then it will start to resorb

4 wearing denture may increase the resorbtion rate especially if

it was not good denture

** Length of wax rim will be like this

Frenumocclusal plane (17-19mm)

Labial sulcus area (22-24mm)

Buccal sulcus (18-20mm)

** Width of the wax rim will be

Incisor area (6-8mm)

Premolar area (8-10mm)

Molar area (10-12mm)

These are notes to take care about:

1 residual ridgeremain after extraction

2 buccal and palatal areas resorb slower

3 decrease of buccal side result in knife edge shape of ridge

4 undercuts and incisive papilla will continue in resorbtion till

they are lost

5 hamular notch dont resorp or change

6 flat ridges will grow wider and wider


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7 resorbtion labilay at incisors and canine

8 resorbtion buccaly at premolar and molar area

9 smaller sizes at buccal and lingual area

10 ridge heights will become lower through time

11 sulcus will become bigger and wider while resorbtion

increase

Mandible resorbtion

The mandible resorbtion is in these areas:

Anteriorly: backward and downward

Premolar area: buccaly inward, lingually outward (smaller in

width and height)

Molar area: the resorbtion is lingually coz buccaly there is

resistance coz of corticated bone so it will occur to the outward

leading to make the crest ridge more buccal and that will result

in wider mandible posteriorly

** the resorbtion will continue with time and mandible will

continue to go downward and downward leading to formation of

the class 3 relationship so the result will be bigger mandible

Position of the wax rim:


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1 center of wax rim in anterior area labial to the crest of the

ridge

2 in premolar area make it in the same range as point 1

3 in the molar area lingual to the crest of the ridge

** remember the wax rim must flush with 2/3 of the retro molar

area

Length of wax rim

Anteriorly from frenum (16-18mm)

Labial sulcus (18-20mm)

Width of the wax rim

Incisor area (4-6mm)

Premolar area (6-8mm)

Molar area (8-10 mm)

These things you must know about the mandible resorbtion:

1 alveolar process will round up and smooth residual ridge will

be formed

2 it will be less vertical labially

3 it will be more vertical at retro molar pad area and frenum coz

they dont change

4 no well formed height

5 reversed ridges is formed

Documents

Prosto Mid Lap