PONTICS IN FPD

BY

KARISHMA ASHOK

ROLL NO: 33

IV/I

INTRODUCTION• Pontics are the artificial teeth of a fixed partial

denture that replaces missing natural teeth,restoring

function and appearance.

• Proper preparation includes a careful analysis of

critical dimension of edentulous area; mesiodistal

width; occlusocervical disatnce; buccolingual

siameter and location of residual ridge.

BIOLOGIC

MECHANICALESTHETICS

PRE-TREATMENT ASSESMENT

PONTIC SPACE:

One function of the fpd is to prevent tilting or drifting

of the adjacent teeth into the edentulous space.

If such movement has already occurred, the space

available for the pontic may be reduced and its

fabrication complicated.

Overly small pontics are undesirable because they

trap food and are difficult to clean.

Orthodontic repositioning, modification of abutments

with complete coverage retainers can be made.

RESIDUAL RIDGE CONTOUR

An ideally shaped ridge has smooth, regular surface

of attached gingiva, which facilitates maintainance

of a plaque-free environment.

Should have sufficient height to allow placement of

pontic such that it apperas to emerge out from the

ridge (mimics appearance of neighbouring teeth).

Loss of residual ridge contour may lead to

unesthetic open gingival embrasures (black

traingles). This leads to food lodgement and saliva

percolation.

Siebert has classified residual ridge deformities into:

Class I: facio-lingual loss of tissue width with normal

ridge height.

Class II: loss of ridge height with normal ridge width.

Class III: a combination of loss in both dimension.

surgical modification

Although pre-prosthetic surgery like ridge

augmentation with a hard tissue graft may be done, it

is not always indicated unless the edentulous site is to

receive an implant.

PONTIC CLASSIFICATION:

Mucosal contact No mucosal contact

- Ridge lap - Sanitary (hygenic)

- Modified ridge lap - Modified sanitary (hygenic)

- Ovate

- Conical

Design location Indication Contra-indication

Materials

1. sanitary/hygenic

Posteriormandible

Non-esthetic zone;Impairedoral hygeine

Minimal vertical dimension

All metal

2. conical Molars withoutesthetic requirement

Posterior areas with minimal esthetic requirement

Poor oral hygeine

All metalMetal-ceramicAll resin

Design location Indication Contra-indication

Materials

3.Modified ridge lap

High esthetic(anteriors, premolars & sometimes molars)

Esthetic concern

Minimal esthetic concern

Metal-ceramicAll resin

4. Ovate Maxillaryincisors, cuspids & premolars

Desire for optimal esthetics ;High smile line

Unwillingness for surgery

Metal-ceramicAll resin

BIOLOGIC CONSIDERATIONS

Aims at maintainace and preservation of residual

ridge, abutments, opposing teeth and supporting

tissues.

Factors:

1. Ridge contact

2. Oral hygeine considerations

3. Pontic material

4. Occlusal forces

Ridge contact

Pressure free contact between the tissue and pontic

is indicated to prevent ulceration &inflamation of soft

tissues.

If any blanching of tissues occurs during try-in,

pressure areas should be identified using disclosing

medium and pontic recontoured until tissue contact is

entirely passive.

Oral hygeine considerations:

Chief cause of ridge irritation toxins released from microbial plaque accumulates between gingival surface of pontic and residual ridge calculus formation and tissue irritation.

Unlike RPD, FPD cannot be removed for cleansing.

Normally where tissue contact occurs,gingival area of pontic is inaccessible. Devices such as proxy brushes, superfloss may be used.

If pontic has a concavity or depression in its gingival surface, there will be palque accumulation which leads to inflamation. Therefore FPD should be checked & corrected before cementation.

Pontic material

Should provide

Good esthetics where needed

Biocompatibility

Rigidity and strength to withstand occlusal forces

Longevity

FPD should be made as rigid as possible, because any flexure

during mastication or parafunction may caus epressure on gingiva

and fracture of veneering material.

Occlusal contacts should not occur at metal-porcelain junctions.

Pontic material should have ability to resist plaque

accumulation(surface roughness should be less)

Therefore, gold glazed porcelain ceramic

Occlusal forces

To withstand occlusal forces, it has been suggested to

reduce the bucco-lingual dimension of the pontic by

30%

But in case of parafunctional habits or accidental

biting on a hard object, this may not be efficient.

Infact, it may impede harmonious and stable occlusal

relationship

Hence, normal pontic width atleast at the occlusal

third is recommended

Exception-when ridge is collapsed bucco-lingually

MECHANICAL CONSIDERATIONS

Factors that lead to fracture of prosthesis or

displacement of retainers:

1. improper choice of material

2. poor frame work design

3. poor tooth preparation

4. poor occlusion

When metal-ceramic pontics are chosen, extending

porcelain onto occlusal surfaces to achieve better

esthetics should be carefully evaluated.

Porcelain may also abrade the opposing dentition if

occlusal contacts are on enamel or dentin.

ESTHETIC CONSIDERATION

• Priority of the patient.

• Gingival interface:

-an esthetically successful pontic will replicate

the form, contour, incisal edge, gingival and

incisal embrassures and color of adjacent tooth.

-attention should be paid to the contour of labial

surface as it approaches the pontic-tissue

junction to achieve a “natural” appearance.

• Modified ridge lap is recommended for most anterior teeth.

It compensates for lost bucco-lingual width in the ridge by

overlapping the existent ridge.

• When esthetics is of utmost concern, yhe ovate pontic

used in conjunction with alveolar preservation or soft tissue

augmentation can provide indistinguishable appearance.

Incisogingival length

Obtaining a correctly sized pontic simply by

duplication of the original tooth is not possible.

Ridge resorption will make the tooth look too long in

cervical region.

However an abnormal labio-lingual position is not so

obvious. Hence it is used to improve appearance by

recontouring giongival half of labial surface.

Another solution is to shape the pontic to stimulate a

normal crown and root with emphasis on CEJ

Or by using pink acrylic

Mesio-distal width:

Frequently space available for the pontic is less than

the contra-lateral tooth

This is due to uncontrolled toth movement which took

place when the tooth was lost and not replaced.

If possible, such discrepancy should be corrected by

orthodontic repositioning

The space discrepancy can also be corrected by

altering the shape of proximal areas

(by duplicating the mesial half of the tooth and

adjusting the size of the distal half)

PONTIC FABRICATIONMaterials available:

advgs disadvgs indications Contra-indications

Metal-ceramic EstheticsBiocompatible

Weaker than all metal pontics

Most situations Long span with high stress

All-metal StrengthSimple procedure

Non-esthetic Mandibular molarsEsp under high stress

Where esthetics is important

Fibrereinforced resin

ConservativeEstheticEase of repair

Limited to short span uniots

High esthetic concern

Long span fpd’s

facings Rarely used-of historic interest only