Pontic: what is dental pontic and pontic design
what is dental pontic?
Is part of fixed partial denture (bridge) which replace the missing teeth, and it’s connected to the retainer by a rigid (solid) connector or non rigid connector, it restores the function and esthetic of the missing teeth.
- The area of contact between the pontic and the ridge should be small and the portion of the pontic close to the ridge should be as convex as possible to prevent entrapment of food under the pontic.
- The pontic should not exert any pressure on the ridge.
- The embrasure area (mesial, distal, and lingual) of the pontic must be wide enough to keep it clean by the patient (allow easy access for cleaning).
- The pontic should be as nearly as possible in a straight line between retainers to prevent the torquing of the retainers and/or abutments.
- The pontic may be made entirely of metal or of combination of metal and acrylic or porcelain facing.
Requirement of good pontic design:
- Biological consideration.
- Mechanical consideration.
- Esthetic consideration.
A- Biological consideration:
Pontic-ridge contact result in a pressure free contact (passive) is indicated to prevent ulceration and inflammation of soft tissue.
The pontic should provide good access for cleaning the basal tissue surface of the pontic and prevent the accumulation of the plaque that is why a glazed ceramics was believed to be the material of choice of pontic (because the acrylic is porous in nature and difficult in obtaining highly polished surface, this will lead to plaque accumulation causing gingival inflammation.
B- Mechanical consideration:
The pontic should be strong enough to withstand occlusal forces and resist deformation.
Mechanical problems may be due to improper choice of material, poor framework design, weak connector and poor teeth preparation. These could lead to fracture of the prosthesis or displacement of the retainer (strong connector to prevent fracture). Good metal ceramic interface to resist porcelain fracture, e.g. strong all metal pontic may be needed in area of high stress than a metal ceramic pontic which is more susceptible to fracture.
C- Esthetic consideration:
The pontic appearance should look like tooth its replace. In excessive bone loss it’s possible to obtain a pontic with natural length by adding pink porcelain to simulate gingival tissue; it should provide sufficient space for facing.
A- Mucosal types (contact):
1. Saddle pontic.
2. a. Ridge lap.
b. Modified ridge lap.
B- Non mucosal contacts:
- Hygienic (sanitary).
- Modified sanitary (perel pontic).
- Bullet (conical or spheroid).
A- Mucosal types (contact):
1. Saddle pontic:
It looks like a tooth (highly esthetic) by masking proximal, lingual and facial embrasure. The tissue surface of the pontic have the shape of the ridge (large concave contact area with the alveolar ridge, prevent the removal of plaque by flossing).
It’s difficult to clean and there is food accumulation between the tissue surface of the pontic and the alveolar ridge. This design of pontic should never be used.
2. Ridge lap & modified ridge lap pontic:
This design gives the illusion of being a tooth but have all convex surfaces for easy cleaning (convex mesial and distal, and flat buccal and lingual). The pontic touches the mid point of the alveolar ridge crest and slopes over the labial surface of the ridge.
The lingual surface has a slight deflection contour to prevent the food impaction and prevent plaque accumulation. It’s less destructive than saddle pontic because it’s easier to clean due to its convexity.
The palatal configuration may lead to increase food impaction and phonation problems. The tissue contact resembles T shape with pointed end toward ridge; it’s the best design of pontic in the appearance zone for all upper and lower teeth.
3. Ovate pontic:
It’s indicated when the esthetic is of primary importance in the anterior region, it has a round end set into a concavity in the ridge which provides good access for good oral hygiene. In contrast to the basic requirement of pontic which suggest the importance of pressure free contact over small area, the round end must be accurately formed to precisely fill the prepared concave recipient site. This type of pontic requires an adequate amount of soft tissue.
## Ridge socket preparation has two types:
- Immediately after tooth extraction: controlling regeneration directly after the extraction, plastic surgery (a surgical depression 2 mm depth 4 mm wide is prepared with a round bur).
After a period of time, the site where the pontic is placed is sculpted with an electrosurgical device prior to placing it.
B- Non mucosal type:
1. Sanitary (hygienic pontic)
The pontic do not have any contact with the underlying tissue, there is at least 3mm space between the ridge and the pontic to facilitate proper cleaning of the site. The pontic thickness should be at least 3mm to withstand the occlusal forces. It’s all made in convex configuration facio lingually and mesiodiatally. It restores the occlusal function and stabilizes adjacent and apposing teeth, and used when the missing teeth are located in a non appearance zone (lower mandibular area), it’s made entirely from metal (full metal).
The disadvantage of this design is the food impaction and tongue habits.
It’s contraindicated in minimum vertical space and where esthetic is important.
2. Perel (arc design) modified sanitary:
This pontic is made in a form of arch way mesiodiatally (concave mesiodiatally in arch way and convex facio lingually), this design added bulk for strength in the connectors and the stress is significantly in the connector and the access for cleaning is quite good.
3. Bullet (conical, spheroidal) pontic:
It’s in the form of bullet; it’s easier for the patient to keep clean but the triangular shaped space around the tissue contact have a tendency to collect food (tendency to collect food debris in the triangular spaces of embrasure). It’s used in replacement of mandibular posterior teeth because esthetic is less important, also indicated for use with a thin mandibular ridge.
It should be made as convex as possible with only one point contact with the alveolar ridge, it’s used when the occlusal 2/3 of the pontic lies in the lower incisors and premolars and sometimes molars because the gingival third is not visible.