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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