Pontic- power point

Pontic
Pontic


•Pontic definition:


Pontic: An artificial tooth that suspended member of the fixed dental prosthesis

that replaces a missing natural tooth, restores its esthetic and function,

it replaces the space previously occupied by the missing clinical crown.

They must be compatible with continued oral health and comfort.

The part that connects the pontic to the abutment is the retainer which is either:

.The rigid (ex. fixed by solder joint) the retainer is called major retainer.
.When the connection is not rigid (flexible) ex. stress breaker, the retainer




is called minor retainer.


A,A three-unit FPD showing the main components.

B,The pontic rigidly attached to crowns on the

abutment teeth. The connectors should occupy

the normal interproximaly contact area and be

large enough for strength but not so large as to

impede plaque control.


•Requirements of pontics:
.Smooth surfaced and convex in all directions.
.Easily cleansable.
.Pinpoint pressure free contact on the ridge.
.No irritation to the gingival tissues.
.Facilitate plaque control.
.Pontic space.
.Strength and longevity.
.Be esthetic.
.Restore function.
.No abutment overloading.
.Color stable.
.Residual ridge contour.





•Functions of pontics:
.Mastication.
.Occlusion.
.Speech.
.Esthetics.




•The components of pontic:


a-Metal backing.

b-Solder joint.

c-Facing.

•The surfaces of a pontic:A pontic has five surfaces:


* The ridge.

* The occlusal.

* The approximal.

* The buccal.

* The lingual.


•Pontic Design:


Proper preparation includes a careful analysis of the critical dimensions of
the edentulous areas: mesiodistalwidth, occlusocervicaldistance,
buccolingualdiameter, and location of the residual ridge.To design a pontic

that will meet hygienic requirements and prevent irritation of the residual
ridge, particular attention must be given to the form and shape of the
gingival surface. The selection of the design depends on the following
factors:

a-Spatial boundaries

b-Shape of edentulous ridge (normal, blunted, or excessive resorption).

c-Maxillary or mandibularposterior arch (in contrast to the mandibularposterior pontic, the maxillary edentulous

ridge is usually broad and blunted and has superior cosmetic effects).

d-Anterior pontic (the overriding cosmetic requirement is that form and
shape reproduce the facial characteristics

of the natural tooth).

The task is to design within boundaries of a tooth substitute that favorably compares

in form, function, and appearance with the tooth it replaces. The tooth substitute must

provide comfort and support to the adjacent musculature, conformity to the food-flow

pattern, convenient contours for hygiene, and cosmetic value, if indicated.


1-The relationship of poetic design to residual ridge:

A, Ridge lap pontic. This type of poetic demonstrates unacceptable excess tissue contact

and is difficult to maintain hygienically.

B,Modified ridge lap poetic. This type of poetic demonstrates acceptable esthetics and

works best with broad edentulous ridges.

C, Stein pontic.This type of poetic, which is designed for sharp edentulous ridges,

demonstrates minimal tissue contact and acceptable esthetics. It is contraindicated in

edentulous ridges with broad bucco-lingual dimensions.

D,Sanitary pontic. This type of poetic is 2 to 3 mm distant from the ridge. This design

is easily cleaned and allows for a free flow of food beneath the poetic. However, it exhibits

unacceptable esthetics.

E,Ovate pontic. This type of poetic exhibits excellent esthetics and function. It produces

minimal tissue contact and is very hygienic. However, if ridge resorptionoccurs, deterioration

of esthetics results.


2-Interproximal contact areasare constructed wider buccolingually

than the solder joint of the permanent splint to provide strength for the splint.

The tissue-contacting surface of a pontic must be flat or convex (never
concave)

to permit efficient cleansing with floss and other home care devices.

3-Edentulous ridge.

4-Opposing occlusal surface.

5-Musculature of tongue, cheeks, or lips.

6-The sanitary pontic design leaves space between poetic and ridge.

7-The saddle pontic design covers the ridge labiolingually. Total

coronal width is usually concave.

8-The modified ridge design uses a ridge lap for minimal ridge

contact.Labial contact is usually to height of the ridge contour

(straight emergence profile).


The deflection of a fixed partial denture is proportional to the cube of

the length of its span.

A,A single pontic will deflect a small amount (D) when subjected to

a certain force (F).

B, Two pontics will deflect 23 times as much (8 D) to the same force.

C, Three pontics will deflect 33 times as much (27 D).


•A-Biologic considerations:


1-Ridge contact: Area of contact with ridge should be small and convex.

2-Oral hygiene considerations.

3-Pontic materials: Differences in the plaque-retaining capacities of samples of

a Type III gold, gold for veneering with porcelain, a vacuum-fired bonded
porcelain Veneer, and an acrylic resin.

4-Occlusal forces: Reduce bucco-lingual width about 30% to lessen occlusal forces an

d will increase 12%in chewing efficiency.


B-Mechanical considerations:

.Improper choice of materials.
.Poor framework design.
.Poor tooth preparation.
.Poor occlusion.
.It can be seen that the maximum tensile stress at the solder joint.




C-Esthetic considerations

1-Incisogingival length.

2-Root can be stained to simulate exposed dentine.

3-Pink porcelain to simulate the gingival tissues.


An abnormally sized anterior pontic space can be restored esthetically by matching

the location of the line angles and adjusting the interproximaly areas.

Large (A)and small (B)pontic spaces. L Dimension a should be matched

in the replacement.


•Classification:
A.Depending on shape of surface








contacting the ridge:

1.Sanitary.
2.Modified sanitary.
3.Spheroidal
4.Saddle.
5.Ridge lap.
6.Modified ridge lap.
7.Ovate.











A,Sanitary pontic.

Band C,Modified sanitary pontic.

D,Placement of the pontic, close to the ridge, has resulted in tissue

proliferation (arrow).


A,Cross-section view of ridge lap pontic.

B,The tissue surface is inaccessible to cleaning devices.


Aand B,FPD with a ridge-lap (concave) gingival surface.

C,When it was removed, the tissue was found to be ulcerated.

D,The defective FPD was recontouredand used as a provisional

restoration while the definitive restoration was being fabricated.


Modified ridge lap pontic.

A,FPD partially seated.

B,FPD seated.


Aand B,A pontic with maximum convexity and single point contact of the tissue

surface is the easiest design to keep clean.

C,Evaluating the contour of three possible pontic shapes (1, 2, and 3).

Contour 3 is the most convex in area Bbut is too flat in area A.Contour 1 is convex

in area Abut is too flat in area B. Contour 2 is the best.

D,An all-metal FPD with a conical pontic, suitable for replacement of

a mandibularmolar.


A,Conical pontics may create food entrapment on broad residual ridges (arrow).

B,The sanitary pontic form may be a better alternative.


Ovate pontic.

A,FPD partially seated.

B,FPD seated.


2. According to Rosenstieldepending on mucosal contact.

a-Mucosal contact ridge lap modified ridge lap ovate conical (contact):

1-Saddle pontic.

2-Ridge lap

3-Modified ridge lap.

4-Ovate.

b-No mucosal contact sanitary(hygienic) modified sanitary (non-contact):

1-Hygienic (sanitary).

2-Modified sanitary (pearl pontic).

3-Bullet (conical or spheroid).


•Modified ovate pontic:


a-Contact more labially than ovate pontic.

b-Easier to clean.

c-No need of surgical augmentation.

d-Push the labial gingival margin away to floss.

•Residual ridge contour:


a-To determine the frequency and the nature of tissue reactions of

underlying residual ridge mucosa to specific pontic designs.

b-To compare the frequency and the nature of tissue reactions of

residual ridge mucosa to various materials used in pontic construction.


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