Pontics Flashcards by Marjorie Wolfe

Pontic Design Biology (3)

Cleansable tissue surface
Access to abutment teeth
No excessive pressure on ridge

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Pontic Design Mechanics (2)

Rigid (resist deformation)
Strong connectors (prevent fracture)

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Pontic Design Esthetics (3)

Anatomy of tooth being replaced
Appears to “grow” out of edentulous site
Sufficient clearance for porcelain

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Siebert Classification of edentulous ridges:
Class N

Minimal width and height deficiency
9% of edentulous sites

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Siebert Classification of edentulous ridges:
Class I

Facio-lingual loss of tissue width
Normal ridge height
32% of edentulous sites

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Siebert Classification of edentulous ridges:
Class II

Normal ridge width
Loss of ridge height
3% of edentulous sites

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Siebert Classification of edentulous ridges:
Class III

Facio-lingual loss of tissue width
Loss of ridge height
56% of edentulous sites

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These pontics have zero tissue contact

Hygienic Pontic

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All metal/Zr - 2 mm of clearance from gingiva

Hygienic Pontic

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Hygienic Pontic provide
Good access for __
But are highly __

hygiene
unaesthetic

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Hygienic Pontic are used only for

posterior FDPs

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A pontic with a concave gingival surface that overlaps the ridge buccally and lingually

Ridge Lap Pontic (Saddle)

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These pontics are not recommended and not hygienic

Ridge Lap Pontic (Saddle)

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Combines the best features of the hygienic and saddle pontics (cleansability and esthetics)

Modified Ridge Lap Pontic

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Slight tissue contact on facial aspect of ridge, giving a natural appearance of a tooth emerging from the gingiva

Modified Ridge Lap Pontic

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All surface should be convex to allow hygiene

Modified Ridge Lap Pontic

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Most common used pontic design

Modified Ridge Lap Pontic

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Not esthetic
Indicated for posterior extraction sites with narrow alveolar ridge
Poor oral hygiene

Conical Pontic (egg-shaped, Bullet-shaped, Heart-shaped)

Most aesthetic pontic design

Ovate Pontic

Depression or hollow in the residual ridge, makes it look like it’s literally emerging from the gingiva

Ovate Pontic

Used in cases where high esthetics is required (high smile line)

Ovate Pontic

What are 3 different treatment approaches for an Ovate Pontic

Socket preservation techniques should be used to avoid the ridge collapse
Soft tissue graft can be made to an old extraction site to create more ridge volume
When there is adequate ridge volume , socket depression can be sculpted with electrosurgery or surgical diamonds

A fixed dental prosthesis in which the pontic is cantilevered i.e. is retained and supported only on one end by one or more abutments

Cantilever pontic

Why should a cantilever pontic never be an ideal TX plan

Unfavorable biomechanics
VERY high risk of failure

What is the only case to consider a cantilever pontic

Replacing a maxillary lateral incisor - pt should have very good posterior teeth support - Pontic should have very light occlusal contact in all excentric movement positions

What are the potential complications of the cantilever pontic

- Torquing of abutment teeth - High risk of retainer decementation

Biological Considerations with a pontic: Tissue contact (2)

- No contact or slight contact - Avoid too much pressure (soft tissue blanching)

Biological Considerations with a pontic: Oral hygiene considerations (2)

- Main cause of tissue irritation is the accumulation of plaque between pontic and residual ridge - Patients need to be taught how to clean these surfaces (Superfloss, proxy brush, floss threader)

Mechanical Considerations with a pontic: Pontic material (2)

- They should be reinforced with a strong framework (becuase they are exposed to increased amounts of load b/c they are long restorations) - Porcelain is too brittle - will break under flexure

Mechanical Considerations with a pontic: Available Pontic Materials (3)

Metal/ceramic (99% of pontics) Resin veneered (not common) Fiber-reinforced composite resin (very weak)

High abrasion resistance (needs to be polished) Good material stability and strengh

Metal/ceramic (99% of pontics)

Low abrasion resistance Dimensional change from water absorption Mechanical retention (not chemical)

Resin veneered (not common)

Substructure matrix of impregnated glass or polymer fiber provides structural strength

Fiber-reinforced composite resin (very weak)

Mechanical Considerations with a pontic: Occlusal Forces (2)

- reducing the buccolingual width of the pontic by as much as 30% has been suggested to reduce the occlusal load on the retainers or/and to follow a narrow residual ridge - although watch out for : cheek or tongue biting, harmony of opposing occlusal relationship, bruxism

Esthetic Considerations with a pontic: Gingival interface (2)

- The greatest challenge is to replicate for the gingival anatomic changes that occur after extraction - In most of the cases duplicating the facial contour of the crown is not enough to accomplish a nice esthetic outcome

What are 3 options for the gingival interface of a pontic

Ridge augmentation (bone graft) Connective tissue graft (soft tissue) Pink porcelain

The buccal plate is usually __ thick

0.5-1 mm

After extraction, the __ is at high risk of resorption

buccal plate

Buccal plate: What is recommended to conserve as much bone as possible

A socket preservation (bone graft)

Esthetic Considerations with a pontic: Correct __ is critical to esthetic pontic design

incisogingival height/ length

A pontic should be interpreted as __

growing out of the gingival tissue

Esthetic Considerations with a pontic: Mesiodistal width

Tooth movement - frequently the available space for the pontic will be bigger or smaller of the contralateral tooth

How to achieve proper mesiodistal width for a pontic

Orthodontics (1st option) Visual perception pontic design

Mesio-distal width When replacing a posterior tooth it is possible to replicate the anatomy of the __ as the original tooth and then modifying the __ to accommodate the overall pontic shape

visible surfaces (mesial) Non-visible surfaces (distal)