Pontics Flashcards
Pontic Design Biology (3)
- Cleansable tissue surface
- Access to abutment teeth
- No excessive pressure on ridge
Pontic Design Mechanics (2)
- Rigid (resist deformation)
- Strong connectors (prevent fracture)
Pontic Design Esthetics (3)
- Anatomy of tooth being replaced
- Appears to “grow” out of edentulous site
- Sufficient clearance for porcelain
Siebert Classification of edentulous ridges:
Class N
Minimal width and height deficiency
9% of edentulous sites
Siebert Classification of edentulous ridges:
Class I
Facio-lingual loss of tissue width
Normal ridge height
32% of edentulous sites
Siebert Classification of edentulous ridges:
Class II
Normal ridge width
Loss of ridge height
3% of edentulous sites
Siebert Classification of edentulous ridges:
Class III
Facio-lingual loss of tissue width
Loss of ridge height
56% of edentulous sites
These pontics have zero tissue contact
Hygienic Pontic
All metal/Zr - 2 mm of clearance from gingiva
Hygienic Pontic
Hygienic Pontic provide
Good access for __
But are highly __
hygiene
unaesthetic
Hygienic Pontic are used only for
posterior FDPs
A pontic with a concave gingival surface that overlaps the ridge buccally and lingually
Ridge Lap Pontic (Saddle)
These pontics are not recommended and not hygienic
Ridge Lap Pontic (Saddle)
Combines the best features of the hygienic and saddle pontics (cleansability and esthetics)
Modified Ridge Lap Pontic
Slight tissue contact on facial aspect of ridge, giving a natural appearance of a tooth emerging from the gingiva
Modified Ridge Lap Pontic
All surface should be convex to allow hygiene
Modified Ridge Lap Pontic
Most common used pontic design
Modified Ridge Lap Pontic
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)
