(2) Introduction to Removable Partial Denture II

8/3/2019 (2) Introduction to Removable Partial Denture II

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Introduction to removable partial denture (RPD)

course

Treatment options for partially edentulouspatients

Slide 2: Definition of RPD:

RPD it is any prosthesis that replaces one or more, but not all

missing teeth. Or we can say some teeth in partially edentulous

arch. It can be removed from the mouth and replaced at well. Note: fixed partial denture (FPD) can be called "bridge"…and it

can't be removed.

Slide 3: Types of RPD:

We classify RPD according to support mainly into two types:

1-mucosally supported OR tissue supported.

This type of RPD is mainly composed of acrylic. But, it isimportant to know that they aren't supported by the

tissue/mucosa one hundred percent. Example: *some of

mucosally supported RPDs achieve their support by the teeth

also and not only from tissues. (Mainly from the edentulous

area).*another example: some clasps that we use for acrylic

partial denture designed in a way that transfer the load to the

abutment teeth (the remaining teeth).so, again they aren't

mucosally supported 100%.

Most of acrylic RPDs is mainly mucosally supported. They don't

achieve much support from teeth. They are called gummo

strippers (because they compress on gum).and these type of

RPDs sink during function. Acrylic RPD can be used as a final

definitive prosthesis. Since, type of material that we use doesn't

indicate if your prosthesis is provisional or definitive. But, most

of the time acrylic RPDs are provisional (temporary.(

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**Acrylic RPDs can have a dual support (i.e. from the tooth

and the tissue.(

2-Tooth supported OR tooth-mucosally supported.

This type of RPD is mainly composed of metal.

Just to refresh your memory

Partial dentureComplete dentureDefinition

Can be increased by

the remaining teeth

(abutment) & not

only from the tissue.

Always from the

tissue

Support - it is a

characteristic of the

supporting tissue to

withstand the

functional forces

during mastication.

Clasps also provideadditional retention

Same as thedefinition

Retention- it is theability of the

prosthesis to resist

dislodgment

Same as the

definition

Same as the

definition

Stability-it is the

ability of the

prosthesis to resist

rotational

movements duringfunction

In conclusion: The concepts of all these 3 terms are the same in

both complete denture and partial denture.

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Retention, stability &

support all are applied for

both complete denture

and partial denture.



For slides (4 to 7): please refer to your slides

& see the pictures.

Slide 4:

Acrylic base

Everything is made of acrylic. The base, the artificial teeth & the

junction between the artificial teeth & the base plate all are

acrylic except the clasps are made of metal.

Metal base

Denture base (called also metal framework) is made of metal

except the artificial teeth & the junction between the artificial

teeth & the metal are made of acrylic.

Slide 5:

This is metal base removable partial denture in maxillary arch.

Slide 6:

This is also another example.

Slide 7: Components of RPD

-Each component will be given in a separate lecture. (Refer to

the slides: these components of metal framework -cobalt

chromium- RPD.(

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Slide 8: Indications

What do we mean by indications? It means when do we prescribe

RPD for patients, instead of No treatment or instead of fixed

partial denture or implant ???? Long span edentulous area.*

For example: missing 3, 4, 5, 6, & 7. In this case, if we want to

fabricate RPD it will be extended from 8 to the lateral incisor.

But, lateral it is not a good abutment. As a result of that the RPD

should be extended to the central incisor. By this you will end up

with a very long bridge & high chance of complications or may

be failure. So, patients can't afford implant therapy. Here RPD is

highly indicated for long span edentulous areas, especially whenwe have multiple edentulous areas. And instead of having 3

bridges, partial denture will replace all these missing teeth. And

you have noticed that artificial teeth can be on the right side, left

side & anteriorly.

* No abutment tooth posterior to the edentulous area.

For example: if somebody has 6, 7 and 8 are extracted. Can we

construct a bridge? No. So, don't do fixed partial denture with

distal extension except if you have very short distal extension

and good abutment. In this case we have free and saddle.

Therefore the option of fixed RPD is dropped, and the only

options that we have are RPD or implant. For some cases the

implant is not an option. So, we have RPD or no treatment.

Hint: some dentists do extension to the bridge for 6 and 7 areas.

After a few months or may be one year, if you hold the 7 areayou can move the bridge 1 cm buccally and 1 cm lingually. And

you can take out the abutment tooth by your hand without need

to the forceps. (I know it's not clear enough but, this is what the

dr. said(!!!!!!!!!.

*reduced periodontal support for remaining teeth.

i.e.: if you have mobile teeth due to periodontal disease. So, how

can you decide which one to extract? According to "Grade of mobility". Grade 1 & grade 2 aren't indicated for extraction.

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Grade 3(severe mobility) is indicated for extraction. Furthermore

if the tooth can't be retained in good health and the patient can't

do proper brushing around this tooth, then extraction is indicated.

But, if the patient can clean the tooth properly extraction isn't

indicated.-Do you think a mobile tooth is a good abutment to construct a

bridge? When you want to fabricate a 3 unit bridge(example:6, 7

are missing) already the periodontal membrane is reduced for the

teeth. The 5 and 8 gain the forces of the missing teeth in addition

to the forces that applied to them. So, what does this mean? RPD

might be indicated in this case. Especially, acrylic RPD. If it is

metal it might be tooth/tissue supported. And if it is only tooth

supported you can distribute the load on more than 2 teeth byapplying rests on all remaining teeth. By this in RPD you can

transmit the forces to more teeth.

*need for cross arch stabilization.

In RPD you can do cross arch stabilization, while bridge is only

on one side.

* Excessive bone loss within the residual ridge.In case of excessive bone loss Implant is not an option. But, only

when we do bone grafting implant is accepted. Sometimes the

patient can't afford for this treatment or even for medical reasons

he can't have it. So; what's the option? RPD. Why?? Because we

have acrylic flange that replaces the missing bone.

* Physical or emotional problems exhibited by patients.

For example: if somebody has missing teeth from canine tocanine, so what's the treatment option? Do we choose implants as

a treatment for this patient? Of coarse no. this patient can't

physically (i.e. ability to eat & to speak) and psychologically

withstand for a period of time without teeth (it is not acceptable).

Therefore RPD is the treatment option & within 3 weeks to 1

month the patient can have teeth and function.

* Esthetics.

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Some people think that implants or even veneers provide best

esthetics. Actually, in some cases they provide the worst

esthetics. So, don't think that implants give the best esthetics. It

might give the least esthetic outcome, while using RPD can give

the best esthetic outcome. That depends on case selection.Dr. said: I remember a 30 years old woman that had 8 implants

and a fixed prosthesis on them. She spends thousands of money

for those implants. After came again to the clinic and complained

that she doesn't like the prosthesis. Unfortunately, we can't solve

the problem now and do a complete denture to her as a better

esthetic option. So, it depends on case selection.

* Immediate replacement of teeth that need extraction.We can't construct a partial denture before extraction of teeth.

So, you extract the teeth and immediately insert them. Especially

that the big psychological trauma for patients is accompanied

with missing or extracted teeth.

* Patient's desire.

Sometimes, we let our patient decide which treatment option he

prefers. Especially if we have an old patient (in his 60s or 70s)the most favorable treatment is to have quick & cheap teeth

(RPD). Or sometimes if you tell your patient about the

complexity of other modalities of treatment, then he will say to

you please do the simplest one.

*Unfavorable maxillomandibular relationships.

For example: if someone has severe class 2 or class 3, implant

dentistry or even fixed prosthodontics is not the straight forward procedure for those patients. But, removable prosthesis is much

easier than fixed & implant prosthesis.(besoholeh mnet3ada el

discrepancy).i.e. if the patient has class 3, what do we need to

do?! Just to retrocline the lower anteriors a little pit and to

procline the upper anteriors a little pit. By this we transfer from

class 3 to edge to edge. Can I do this in implants? No. why??

Because, if we want to do it by putting implant we should direct

them labially. And unfortunately there is no enough bone andmay be we cause sever recession of the gum.

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Slide 9 + slide 10: Advantages of RPD

-it restores function and esthetics. And this is what we want most

of the time.

-it improves speech and occlusal stability. This point fulfills the

criteria of a dental prosthesis which is function (includes

mastication and speech), esthetics and stability.

-replaces one or more missing teeth in one side or both sides of

the upper or lower jaw. So, one

prosthesis replaces many missing teeth.

-more affordable than fixed. Because it is very cheap. For

instance; acrylic partial denture costs 50 J.D and one implant 650

J.D.

Some students, who have relative dentists that say to them that

RPD is a part of history, don't believe them. It is still wherever

you go in the world…in the United States… in Australia … in

Canada…& in Europe; there are cases that must be treated only by RPD. For example: postmenopausal woman is highly exposed

to osteoporosis and they can't have implants. So, osteoporosis

contraindicates the use of implants. And according to this the

option is RPD. Furthermore, no way to plan the implant case

without starting with RPD. Because, we don’t know the final

outcome. To conclude, you must have to start with complete

denture for edentulous patients and with RPD for partially

edentulous arches.

-replaces missing soft tissue and bone as well .

-less accurate techniques than fixed prosthesis and easy occlusal

adjustments.

In RPD occlusal adjustments is only for 5 minutes, but in bridges

for 0.5mm we need have an hour (in order to remove the

ceramic.(

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-easy to clean because it's removable.

-may provide as an interim prosthesis. (Something provisional.(

-quite easy to adjust and add more teeth if later loss occurs. (We

will talk about it in provisional restorations.(

By the way any prosthesis has advantages and disadvantages. If

you have done RPD and the patient doesn't like, he can get rid of

it.. But in case of implant there is prescription and installation.

So, you can't remove it easily. So, you must remove part of the

bone.

If you construct a bridge can you do this (remove it)? Another

bridge means that cut the bridge, refine preparation again andtake a new impression (because already teeth are prepared and

the bridge is cemented).in abroad, bridges cost 5000 dollars and

even in Jordan 4 unit bridge costs 800 J.D.

Don't think by implant dentistry you can get rid off traditional

prosthodontics. It is still indicated in many cases. Especially, in

our countries.

Slide 11 -15: Disadvantages of RPD

-Can cause caries for adjacent teeth depending on the design of

the RPD, age of the patient, and the oral hygiene efficiency.

Some patients have bad oral hygiene and this indicates caries.

Such criterion is not limited only for RPD. It is also suitable for

fixed partial denture in which they will have more serious

carious cases.

-Can damage the supporting tissues if poorly designed and cause

tooth loosening and mucosal ulceration. Especially if it is tissue

supported can cause trauma.

-Unsuitable for many patients who don't like removable

prosthesis. I.e. a lot of patients they are reluctant especially

young patients. They don't like to remove their prosthesis andthen retain it. (It is not acceptable socially.(

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-The RPD rotates during function especially the mucosally or

dually-supported one which reduces efficiency and increases

trauma. So, RPD during function rotates not as fixed partial

denture.

- Its construction involves some preparation and adjustment of

the remaining dentition. We need to do adjustment on teeth

especially in metal framework in which we have rests and so

on…

-The acrylic teeth wear and require later replacement. When

acrylic opposes teeth the wear is more than in acrylic teeth incomplete denture. That's regarding to the hardness number of

enamel which is more than acrylic. (For enamel it is 350, and for

acrylic it is 30).but, it is not a big problem. We can replace the

distorted teeth by other new acrylic teeth.

-The clasps may be unaesthetic if placed anteriorly. This is really

a big disadvantage. For example: if the patient with missing

canine (3) or (4), you need a clasp for retention on the canine.And this is not esthetic.

-May stimulate candidal infection of the mucosa underneath

especially if not cleaned frequently and after meals. Candidal

infection for those patients is very common for two reasons: 1)

poor oral hygiene. 2) Or if the denture is ill-fitting. And most of

the time combined (both of them).we can notice this infection on

the hard palate.

-The acrylic has low impact strength and may fracture.

- Bone resorption if mucosally or dually-supported and frequent

relining may be required. After bone resorption there will be a

space between the denture and the bone leading to more

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movement and more damage. The best solution is to reline in

which we add acrylic on the fitting surface of the prosthesis.

- Bulky if compared with fixed prosthesis, and so uncomfortable

for new wearers. As we noticed in RPD we fulfill the hard palateto replace missing lateral. In contrast, in fixed prosthesis it is

very tiny.

-Some patients complain of reduced thermal sensation with

upper RPD covering the palate. When you eat a piece of cake

thermal and taste expansion will be reduced.

- Better to be removed at night for tissue re-adaptation. Most of

fungal infections occur in patients that wear their RPD 24 hours

.(^_^)

Slide 16: Treatment options for partially edentulous patients

What are the treatment options for partially edentulous patients?

There are 4 options.

1( NO treatment

2(RPD

3(FPD

4(implant-supported prosthesis (fixed, removable.(

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Each one of these 4 options is suitable. So, it is not necessary to

follow this sequence. For example: if we have two patients and

both of them with missing laterals. As a treatment option for the

first patient we decide to do RPD. And for the other we decide to

do a bridge depending on many factors that we will talk about

them later .

Slide 17: **veeeeeeeeeeeeeeeery important slide

What are the steps involved in construction of removable partial

dentures? (Metal-acrylic and acrylic only.(

Metal-acrylic which is metal framework .-

Acrylic only which is acrylic RPD.

Now we will talk about acrylic RPD only, and metal acrylic we

will talk about it later .

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Hint: implant doesn't mean fixed prosthesis only.

Mount casts on articulator

analysis of diagnostic casts



)* Dr. mentioned: after that

We take

a primaryimpression.

So, what

type of material

should we use?

Only alginate. Keep in

your mind that impression

compound can't be

used for edentulous patients.(

Tooth modifications final impressions

Final impressions jaw relations (if needed*(

Try-in metal framework try-in of RPD*

Jaw relations insertion of RPD

Try-in of RPD

Insertion of RPD

) * Dr. explained according to treatment plan:

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Data from history

and oral

examination*

Treatment plan*

Designing RPD

Metal acrylic RPD Acrylic only RPD*

Review



)* Dr. explained according to acrylic RPD: in some cases we need special

tray and final impression. in other cases final impression is enough. For

instance: if the patient with missing lateral, primary impression is enough.(

)* Dr. explained according to jaw relations: in some cases you can

articulate the models without need for the record block because we have

remaining teeth and it is not as in complete denture.(

)* Dr. explained according to try-in of RPD: also it depends on the case. if

the patient with missing lateral no need for try-in. but, if all anterior teeth

are missing in this patient you need to do try-in.(

Slide 18: Provisional/temporary RPDs

We have 3 types of PROVISIONAL RPDs:

1(Interim RPD

2(Transitional RPD

3(Treatment RPD

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This sequence may be changed. Sometimes

you need treatment planning for mountedmodels & sometimes you can do treatment

planning without mounted model. Example:

patient with missing lateral doesn't need

mounted model in comparison to patient

with multiple missing teeth & supra eruption

of some teeth, we can't plan the case in

patient's mouth because we might need more

than two hours. Also we can't see from

behind the teeth. So, we mount the model.

Then do treatment plan & decide is it acrylicRPD or metal RPD).



*Does interim RPD means acrylic partial denture? No, it can be

metal not only acrylic.

Slide 19: Interim RPD

*Indications.

What does interim mean? Interim means provisional prosthesis

that can be replaced by another definitive prosthesis. Example: if

somebody has missing lateral and supposes that he is 17 years

old. As a first treatment option we put RPD- for 2-3 years- until

he becomes 20 years old. After that implant therapy will replace

it. In this case we use RPD as a temporary solution to be replaced

by another definitive prosthesis. By the way definitive treatmentcan be another partial denture not necessarily implant.

*Materials. (Cold-cure acrylic/ heat-cure acrylic/acrylic &

metal). Most of the time, we use heat-cure acrylic.

*Clinical procedures. Exactly the same as I just mentioned

above. But, in cold cure or metal the steps are different from that

applied to the heat cured.

*Laboratory procedures. Include many steps:

Step 1: Classification of the models.

Step 2: Do survey to determine the desirable and undesirable

undercuts.

Step 3: Block out the undesirable undercuts.

Step 4: Wire binding and preparing the clasps.

Step 5: Setting of teeth.Step 6: Denture base.

Or you can do the two last steps (5&6) together .

After that you do processing (includes flasking, dewaxing,

packing, curing, deflasking, finishing and polishing.(

Slide 20-22: -Refer to your slides to see the pictures.

Take this case for example: this is 21 years old female. She hadanterior bridge (fixed partial denture) when she was 16 years. As

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you see in the picture there is a fracture in the ceramic. The

patient didn't like the color of her teeth and their level. So, the

bridge is defective, In addition to the endodontic problems that

she had. If we want to correct the deficiency we cut the bridge

and get rid off it. We can't leave our patient without teeth!!!!!.Since, we need a provisional treatment (i.e. we need RPD as an

interim prosthesis that will be replaced by definitive one). So,

this is an interim RPD and after this she had two implants and a

bridge on these implant. (Here one tooth is added and another

one is extracted).This example is introduced to show you that

RPD is part of prosthodontic treatment, not considered as a part

of history.

Slide 23: Transitional RPD

*Indications.

It means that the patient is in the process of being edentulous.

There are a lot of possibilities for patients that have transitional

RPD like: neglected mouth, poor oral hygiene, decayed teeth and

mobile teeth. To avoid the big psychological trauma/impact of

your patient you don't take all teeth out, although you know thefate of these teeth is extraction. But, you do the process slowly to

reduce the psychological trauma. For example: if your patient

has extracted molars and the remaining teeth are from 5 to 5.

Then you construct an acrylic denture and start to extract the

worst teeth that your patient complains about. And then add a

tooth every month until the patient has a complete denture base.

Finally you construct a new complete denture.

*Materials (heat-cure acrylic/acrylic & metal.(

*Clinical procedures.

*Laboratory procedures.

You should know how to add a tooth. (These procedures

described in chapter 19 in your book .(

Slide 24: Treatment RPD

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*Indications.

*Materials (acrylic & tissue conditioner .(

Tissue conditioner is a very soft material & it still soft only for

one week. We put it on the fitting surface of the denture, In order to recover the lesion (that caused by traumal infections.(

These RPD called "treatment RPD", because we use it for

treatment purposes.

Just to know: soft acrylic considered as another material that can

be used.

*Clinical procedures.

*Laboratory procedures. The only difference is that you needspace for tissue conditioner. So, before you do the acrylic base

you add spacer. Same procedure that we do in the special tray in

which we use wax spacer and acrylic. When you remove the wax

spacer there will be a space for the impression material. Here is

the same concept; you add wax spacer and construct the acrylic

partial denture (can be cold-cure acrylic). After construction you

will remove the spacer. So, you will end up with space in the

partial denture and then add the tissue conditioner and place it in patient's mouth.

Wish you all the best…& forgive me for any mistake…

Done by: Fatina akel

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Tooth-mucosa supported RPD

Documents

(2) Introduction to Removable Partial Denture II