Date post: | 21-Apr-2017 |
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PONTICS IN FIXED PROSTHODONTICS
DEFINITIONThe Glossary of prosthodontic terms Pontics- An artificial teeth on a fixed partial
denture that replaces missing natural teeth, restores it’s function and usually fills the space previously filled by the natural crown.
Tylman defines Pontics as the suspended member of a fixed partial denture which replaces the lost natural tooth, restores function and occupies the space of the missing tooth.
IDEAL REQUIREMENTS
1. Depending on the Mucosal contact 2. Depending on the materials.3. Depending upon the Method of
fabrication
CLASSIFICATION
With mucosal contact
Ridge Lap Pontic
Modified ridge Lap
Ovate Pontic
Conical Pontic
MUCOSAL CONTACT
Without mucosal contact
Sanitary pontic Modified sanitary Pontic
concave fitting surface overlaps the residual ridge buccolingually,
simulating the contours and emergence profile of the missing tooth on both sides of the residual ridge.
Disadvantage - plaque accumulation and tissue inflammation
SADDLE OR RIDGE LAP PONTIC
MODIFIED RIDGE LAP PONTICThe modified ridge lap design overlaps the residual ridge on the facial (to achieve the appearance of a tooth emerging from the gingiva) but remain clear of the ridge on the lingual.
Mesiodistal surface is made convex to avoid food entrapment.
Tissue surface - T-Shaped
Also called bullet-shaped Easy cleansibility made as convex as possible, only one
point of contact at the center of the residual ridge.
recommended for mandibular posterior teeth where esthetics is a lesser concern and where ridge is knife-edged
CONICAL PONTIC
most esthetically appealing
Its convex tissue surface resides in a soft tissue depression in the residual ridge, which makes it appear that a tooth is literally emerging from the gingiva.
OVATE PONTIC
allows easy cleaning permits easier plaque
control by allowing gauze strips and other cleaning devices to be passed under the pontic
Occlusogingival height should be 3mm.
Disadvantage- entrapment of food particles , unesthetic
SANITARY OR HYGIENIC PONTIC
Types of sanitary pontics
Bar Sanitary pontic Conventional or fish belly pontic Modified sanitary / Perel pontic or Arc-fixed pontic
2. Materials All metal- Gold, cobalt-chromium, nickel- chromium etc.
Non metallic – Porcelain
Combination –1. Metal and ceramic
2.metal and resin
Good strength ,Single step procedurePoor aestheticsIndications- Mandibular molars , Bruxism Aesthetic ,
Biocompatible Difficult to fabricate Most commonly indicatedContraindication – Long span bridges
Conventional gold alloy substructure Less strength & abrasion resistance , StainingIndication – Long-term provisional restoration
3. Method of fabrication
a. Trupontic – Large bulk of gingival porcelain adapted to the ridge.
A horizontal tubular slot in the facing Retention – Tubular slot and proximal
bevels
b. Interchangeable facings – vertical slot in flat lingual surface, which is retained with a lug that engages the retention slot.
Tissue contact towards the backing.
c. Sanitary pontic –There is a flat surface towards the occlusal with a proximal slot
d. Pin facing – A flat back facing with two horizontal pins for retention.
e. Reverse pin facing – Porcelain denture teeth can be modified to be used as the bridge facing. Porcelain is added to the gingival end of the facing. It is adapted to the ridge and multiple precision pin holes are drilled into the lingual surface with a tungsten carbide drill. Nylon bristles are placed in the holes and incorporated into the backing wax pattern. This facing affords a good retention when a deep overbite would force the use of very short pins in a conventional facing.
f. Porcelain fused to metal facing – When maximum aesthetics is required particularly for an anterior tooth, this pontic is indicated.
g. Harmony facing – This facing is supplied with an uncontoured porcelain gingival surface and usually two retentive pins on the lingual side. The gingival area is adapted to the ridge and then reglazed.