|Year : 2016 | Volume
| Issue : 2 | Page : 84-88
Unconventional pontics in fixed partial dentures
Mansi Manish Oswal1, Manish Sohan Oswal2
1 Assistant Professor, D.Y. Patil Dental School, Lohegoan, Pune, Maharashtra, India
2 M.D.S, Prosthodontics, D.Y. Patil Dental School, Lohegoan, Pune, Maharashtra, India
|Date of Web Publication||25-Oct-2016|
Mansi Manish Oswal
Senior Lecturer, Department of Prosthodontics, D.Y. Patil Dental School, D.Y. Patil Knowledge City, Lohegoan, Charholi Budruk, Pune-412105, Maharashtra
Source of Support: None, Conflict of Interest: None
Clinical success of fixed prosthodontics is dependent in part upon the type of pontic design. The selection of pontic design plays an important role in the outcome of the treatment. At present, there are many different pontic designs and materials present in the market. For some patients, one pontic may have an advantage over another and the choice is a matter of preference with the operator. It is recognized that clinical circumstances will require infinite variations. Hence, the present study briefs about the unconventional pontic designs which can be used on regular basis for better clinical results.
Keywords: Arc-fixed partial denture, hollow pontic, inzoma pontic, ovate pontic, stein pontic
|How to cite this article:|
Oswal MM, Oswal MS. Unconventional pontics in fixed partial dentures. J Dent Allied Sci 2016;5:84-8
| Introduction|| |
The dental arch is in a state of dynamic equilibrium with the teeth supporting each other. When a tooth is lost, the structural integrity of the dental arch is disrupted and there is a subsequent realignment of teeth until a new state of equilibrium is achieved. Hence, it is very essential to replace this lost tooth as early as possible. This can be achieved with the help of a fixed partial denture.
The restorations of edentulous areas with fixed partial dentures (FPDs) present a particular challenge for the clinician. Because of their ease of use and favorable long-term results, conventional FPDs represent the most popular treatment measure today. In these restorations, the pontic must fulfill the complex role of replacing the functions of the lost tooth, achieving an esthetic appearance, enabling adequate oral hygiene, and preventing tissue irritation. In addition, the pontic must meet certain structural requirements to ensure the mechanical stability of the restorations.
The pontic or an artificial tooth is the main component of a fixed partial denture. The word pontic is derived from the Latin “pons” meaning bridge. The pontic is defined as “the artificial tooth suspended from the abutment teeth.” In this role, the pontic should restore function, provide esthetics and comfort, be biologically acceptable, permit effective oral hygiene, and preserve underlying residual mucosa.
According to the glossary of prosthodontic terms-8, a pontic is defined as “an artificial tooth on a fixed partial denture that replaces a missing natural tooth, restores its function, and usually fills the space previously occupied by the clinical crown.”
Tylman defines pontic as “the suspended member of a fixed partial denture that replaces the lost natural tooth, restores function, and occupies the space of the missing tooth.”
Rosenstiel defines pontic as “the artificial teeth of a fixed partial dental prosthesis that replaces the missing natural teeth, restoring function and appearance.” The pontic, as it mechanically unifies the abutment teeth and covers a portion of the residual ridge, assumes a dynamic role as a component of the prosthesis and cannot be considered a lifeless insert.
William Howard Ueno and Clarence Prui  in 1982 gave the standards of pontics design which stated that:
- Tissue surface of the pontic should be convex for ease of cleaning
- Pontics should never have positive pressure on the underlying tissue
- Pontics and connectors must be of adequate built to withstand occlusal forces
- Pontics should restore esthetics.
The commonly used pontic designs are ridge lap pontic, modified ridge lap pontic, sanitary, conical, and ovate pontic.
This article will be discussing the modified or not commonly used pontic designs.
| Modified Ovate Pontic|| |
Proposed by Liu in 2003, the modified ovate pontic design was developed to circumvent the problems encountered with the ovate pontic. The modification of the ovate pontic involves moving the height of contour at the tissue surface from the center of the base to a more labial position. The modified ovate pontic does not require as much faciolingual thickness to create an emergence profile as in [Figure 1]. It is much easier to clean as compared to the ovate pontic owing to the less convex design. Its major advantage over the ovate type is that often there is little or no need for surgical augmentation of the ridge.
The height of contour at the tissue surface of the pontic is 1-1.5 mm apical and palatal to the labial gingival margin. Dental floss can be used to push the labial gingival margin away and cleanse the tissue surface without any difficulty, in contrast with other pontic types. The labial gingival margin rebounds after the dental floss is removed. The tissue surface of the modified ovate pontic is less convex than that of the ovate pontic. It has more effective air seal for better speech than modified ridge lap. The disadvantage is it may leave a shadow in the apical area of the tooth at the gingival margin if Class I defect and high smile line is present.
In ridge lap, pontic dental floss cannot contact the pontic tissue surface in the concavity. In modified ridge lap, pontic dental floss can contact more of the tissue surface, but a concave area remains in the center of the tissue-contacting surface that cannot be cleansed. In ovate pontic, dental floss can be brought into intimate contact with most of the tissue-contacting surface. For modified ovate pontic, dental floss can be brought into intimate contact with the tissue-contacting surface.
According to Chun-Lin Steeve, the following advantages may be observed when using the modified ovate pontic:
- Excellent esthetics because it produces a correct emergence profile
- Fulfilled functional requirements
- Greater ease of cleaning compared with the ovate pontic
- An effective air seal, which eliminates air or saliva leakage
- The appearance of a free gingival margin and interdental papilla
- Elimination or minimization of “black triangle” between the teeth
- Little or no ridge augmentation required before the final restoration.
Modified sanitary pontic, arc-fixed partial denture, or a “perel pontic”
Tjan in 1983 introduced a new concept of sanitary “arc-fixed partial denture” for the lower posterior missing teeth. The pontic and connector design described reproduced anatomic contours of a certain portion of the buccal and lingual surfaces. This design was easy to keep clean which led to wider acceptance of this design among dentist and dental technicians. Its gingival portion is shaped as an archway between the retainers as in [Figure 2]. It is also less susceptible to tissue proliferation that can occur when a pontic is too close to the residual ridge.
|Figure 2: Modified sanitary pontic, arc-shaped undersurface of the pontic|
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Indications for the arc-fixed partial denture:
- Extreme resorption of the alveolar ridge
- Shallow vestibular trough
- Insufficient or lack of attached gingiva
- Previous periodontal treatment or surgery
- High muscle or frenulum attachments.
This type of pontic does not contact the edentulous ridge. It is generally used when the edentulous space is small mesiodistal, large occlusocervical, or both. This type permits large pieces of food to lodge in the space between the pontic and soft tissue and, therefore, is annoying to the patient. However, the food can be dislodged easily by swishing fluids through the larger space.
It is variation of the modified ridge lap pontic. It is designed for sharp edentulous ridges, exhibits minimal tissue contact, and offers acceptable esthetics as in [Figure 3]. It is contraindicated in edentulous ridges with broad buccolingual dimensions.
In this design, the pontic contacts without pressure. Only the tip contacts the ridge or buccal surface, depending on the relationship of the residual ridge, the opposing occlusion as in [Figure 4].
Custom designed hollow pontics have been used by many laboratories to reduce the cost of the metal-based ceramic pontics. This is not the only advantage of these pontics. The other advantages which came forward were:
- Reduction in metal porosity as there was less metal in the pontic
- Easier soldering when necessary, due to the absence of large heat sinks
- Potential improvement in strength due to the sandwich of porcelain-metal, it presents high resistance to tensile force
- The technique given is carving a solid pontic in wax and then hollowing the center of the wax pontic from underneath as in [Figure 5]. Porcelain application involves filling the hollow center with porcelain firing two or more times.
This is an innovative approach toward pontic design. It was given by Malone and Koth, Alton. In this design, the horizontal ridges were added. In a posterior inzoma pontic, the buccal and lingual ridges are added on abutments for porcelain support. In an anterior inzoma pontic, the labial horizontal ridges are added to prevent flaw migration as in [Figure 6].
This is an attachment that is placed entirely within the pontic. It is particularly used in tilted abutment cases. The wax pattern for the anterior 3 unit segment is fabricated first with a distal arm attached to the pier abutment as in [Figure 7]. Invest, burn out and cast the mesial half, finish it, and seat it on the cast. Place the plastic pattern down into it, wax the distal retainer and the disto-occlusal two-thirds of the pontic pattern as in [Figure 8]. Cement the mesial segment first followed immediately by the distal segment. No cement should be placed between the two segments of the pontic.
|Figure 7: Mesial half cemented first and the distal half having the pontic|
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|Figure 8: Distal retainer with the wing the mesial retainer with the pontic stabilized with a cross pin|
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Cross-pin and wing
They are the working elements of a two-piece pontic system that allows the two segments to be rigidly fixed after the retainers have been cemented. The distal retainer has a wing which is cemented first and the retainer pontic segment mesially is seated last.
Then, a tapered pin is driven through the pontic, the wing and back through the pontic as in [Figure 9]. This can be used in pier abutments or in cases where the path of insertion is not similar. It is a kind of nonrigid connector.
|Figure 9: Tapered pin driven through the pontic, cemented cross pin, and wing pontic|
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| Discussion|| |
The success or failure of a fixed partial denture depends entirely on the design of each component. The design of pontic is dictated by function, esthetics, ease of cleaning, patient comfort, and the maintenance of healthy tissue in the edentulous ridge.
Proper design is more important for cleansability and good tissue health than the choice of materials. It should be borne in mind that the pontic not only replaces the lost tooth but also preserves the remaining tissues. Because some of the supporting tissues are lost when the tooth is removed and the pontic lies over the tissues rather than growing from it, certain modifications such as surgical procedures for the correction of the defect or the use of pink porcelain have to be considered.
The contour and nature of the pontic contact with the ridge are very important. The designs of mucosal surface of a pontic also saw changes from a positive contact with the ridge to a passive contact and then a design that has no contact.
After a proper evaluation of the case is done and keeping all the pontic selection criteria in the mind, a pontic design best suited for the situation is selected. The prognosis of this design will depend on the way the patient maintains the hygiene around this pontic. Pontic designed for placement in the esthetic zone (areas of high visibility) must produce an illusion of being a tooth growing out of the gingival tissues. The tooth should maintain a balance between the remaining teeth and should be in proportion with the orofacial structures. At the same time, the hygiene maintenance in these pontics should also be taken care of.
Although no pontic can be considered ideal, we should strive to select the one that fulfills the greatest number of requirements for health of the oral tissues, strength of the fixed partial denture, function, and last but not the least esthetics that makes the pontic more appealing to the eye of an observer.
| Summary|| |
“What you focus determines what you miss” - a missing tooth is always a center of focus as the integrity of the stomatognathic system depends on the replacement of this tooth. The guidelines laid down should be followed to obtain a successful fixed partial denture.
Pontic is an integral part of a fixed partial denture. Hence, the selection of a pontic should be done only after evaluation of the pontic space, the retainers to be used, esthetics, ridge condition and contour, oral hygiene habits of the patient, and occlusion of the patient.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]