An Ovation To The Ovate Pontic

Dr. Nivedita Paul, Dr. Gaurang Mistry, Dr. Padma Priya Puppala, Dr. Sheetal Parab, Dr. Mayuri Bachhav, Dr. Mishal Desouza

Post-graduate Student,

Post-graduate Student,

Professor and Head,

Professor,

Associate Professor.

Department of Prosthodontics and Implantology, D.Y Patil University,

School of Dentistry, Navi Mumbai, India.

ABSTRACT :

An artificial tooth on a fixed dental prosthesis that replaces a missing natural tooth, restores its function, and usually fills the space previously occupied by the clinical crown is known as a pontic. It serves the purpose of replacing a tooth for aesthetic as well as function. In the anterior aesthetic zone, it is essential to create a pontic design that takes into consideration, ease of cleaning and elimination of “black triangles’’. The ovate pontic was developed to create an illusion of a tooth emerging from the gum. It has a convex design that creates a concave gingival tissue form. A modified ovate pontic design was developed to overcome the drawbacks presented by the ovate pontic. The modified ovate pontic has less soft tissue-contacting surface and less curvature than the ovate pontic. This article presents a case report of a modified ovate pontic design for the replacement of an upper anterior tooth that provides both healthy tissue as well as aesthetics.

Keywords : Ovate pontic, Black Triangles, Aesthetics, smile design, Pontic design, Emergence profile

Citations : Paul N, Mistry G, Puppala P, Parab S, Bachhav M, Desouza M. An Ovation to The Ovate Pontic- A Case Report. J Prosthodont Dent Mater 2021;2(1): 75-81.

INTRODUCTION :

After extraction of a tooth, it has been reported that the bundle bone becomes non-functional through the loss of periodontal blood supply and undergoes complete resorption in the first few weeks of the extraction1. It is essential to preserve interproximal soft tissue and to avoid alveolar bone from collapse after the extraction of a tooth including the socket size and shape of the gingival tissue in order to maintain the tissue height and fill the extracted site with the provisional pontic immediately.

Advances in the field of restorative materials allow a lost tooth to be replaced by artificial tooth structure that is virtually indiscernible from the original but local defects of the alveolar ridge often complicate restorative measures. A number of techniques that preserve the alveolar ridge and surgically rebuild defective sites have been suggested. These methods include buccal crown-lengthening procedures and ridge augmentation procedures which lead to an increased frequency of satisfying ridge contours.

In situations where surgical pre-treatment is undesired or contraindicated, various prosthodontic techniques are available to compensate for lost papillae or alveolar ridge defects, such as adjustment of the contact point, reduction of the embrasure space to create a papillary illusion and use of pink ceramics2. In addition, the basal contour of the pontic has been modified to enhance esthetics and function in the anterior area. Long-term provisional restorations are integral to a successful treatment.

Evolution of pontic designs

Pontic of fixed partial dentures (FPDs) must fulfill requirements that are in synchronization with esthetic, functional as well as mechanical needs.

For years, a controversy existed regarding the pontic surface facing the tissue. With use of the full ridge lap pontic, alveolar ridge deficiencies were accommodated, but oral hygiene was difficult because of the concave pontic design. The modified ridge lap pontic and the sanitary pontic were introduced to minimize or even avoid any contact between the pontic and the mucosa1 which improved hygiene and esthetics, but food was still seen to be getting trapped at the open area at the lingual triangle. There was also still a need for a design that supported the gingival contours and eliminated the ‘black triangle’ or open gingival embrasures.

The term “Ovate pontic” was first coined by Dewey and Zugsmith in 1933. An “ovate pontic” was introduced by Abrams in 1980 to fulfill esthetic and functional requirements.

According to the glossary of prosthodontic terms, Ovate pontic is defined as a pontic that is shaped on its tissue surface like an egg in two dimensions, typically partially submerged in a surgically prepared soft-tissue depression to enhance the illusion that a natural tooth is emerging from the gingival tissues. The convex design of this pontic was intended to form a concave soft tissue outline in the site of the alveolar ridge mucosa.

The ovate pontic provided excellent esthetics and emergence profile and was easier to clean as compared to the modified ridge lap pontic. Phonetically, it was more effective because of its more effective air seal. It created an illusion of free gingival margin and papilla and minimizing black triangles. But since this design came requires sufficient facio-lingual width and apico-coronal height to incorporate the pontic within the edentulous ridge. It had a limited application in a thin, knife-edge residual ridge. A surgical augmentation procedure was required when the ridge dimensions are inadequate.

Chiun-Lin Steven Liu in 2003 introduced the “modified ovate pontic” to overcome these shortcomings5. It provided a greater ease of cleaning as compared with the ovate pontic; an effective air seal, which eliminated air or saliva leakage; the appearance of a free gingival margin and interdental papilla; elimination or minimization of the "black triangle" between the teeth; and little or no ridge augmentation required prior to the final restoration.

The modification of the ovate pontic involved 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.

The following case demonstrates the use of a modified ovate pontic design:

CASE REPORT

A 30-year-old female patient reported to the Department of Prosthodontics with the chief complaint of a broken anterior tooth for which she desired a replacement (Fig 2). She had an esthetic concern regarding her smile since she was not satisfied with her existing broken prosthesis.

On examination, it was observed that her missing right maxillary central incisor (11) was replaced by resin bonded prosthesis and it was debonded. Her left maxillary right lateral incisor (21 and 12) was tilted buccally and the lingual surface of both abutment teeth had been roughly prepared for the fabrication of the Maryland bridge. It was also noted that her left lateral incisor was showing irregular incisal edge morphology. The pontic space was noted to be more than required width of central incisor.

Clinical Treatment

Diagnostic impressions were made and the space for the modified ovate pontic was evaluated. followed by the cast being scraped at the region of the missing tooth, to plan for the site of the modified ovate pontic. This was followed by mock preparations of the adjacent teeth and diagnostic wax up was done for the maxillary central incisors as well as lateral incisors, with the 22 being prepared for a laminate. A provisional bridge was fabricated in tooth-colored heat cured acrylic resin by the indirect technique using the putty index. Tissue surface of the pontic was kept highly polished so that irritation to tissue and plaque accumulation can be avoided.

The adjacent teeth were prepared to receive E-MAX restorations. Gingivoplasty was performed in the 11 region with a foot-ball shaped diamond bur. A 30- 40degree gingivoplasty was made in the labial edentulous area and extended apically and palatally 1-1.5mm from the labial gingival margin. The palatal edentulous area was prepared to create a shallow concavity (fig 4).

The provisional was built to create a modified ovate pontic with a shallow convexity and it was inserted right after the gingivectomy procedure. It was more labially placed on the ridge as opposed to an ovate pontic. Cementation of the provisional restoration was done with help of eugenol-free interim luting agent. (Fig. 5)

The tissue condition both at the abutment teeth and the pontic were monitored after 1 week, 1 and 3 months in each recall, appointment health of soft tissue was assessed by removing the provisional restoration, checking the ovate pontic sight for absence of ulceration or extravasations of blood vessels. Pink healthy tissue and minimal tissue rebound was expected. At each visit, the modified ovate pontic was polished on the tissue surface. After three months, the final polishing of the teeth to receive E-Max restorations (21&12) as well as the laminate preparation for the 22 was done and a final impression was taken (fig. 6). At this point the appropriate shade was selected and conveyed to the ceramist.

On receiving the restorations, the restoration’s complete seating and marginal adaptation were verified and no adjustments were required. The anterior area was isolated and the final restorations were bonded to the tooth surfaces (Fig. 7, 8). Controlled physiologic pressure was used at the pontic site to enhance the interdental papilla and create the illusion of pontic emerging from the soft tissue.

DISCUSSION :

The advent of implant supported prosthesis has significantly eliminated using two abutments to support a pontic. However, with a few limitations of implant supported prosthesis, fixed partial dentures are the definite option, while keeping in mind the conservation of tooth structure and the placement of a minimum amount of restorative material in contact with gingival tissues.

The ovate pontic was developed to fulfill esthetic and functional requirements. Its convex pontic design was intended to fabricate a concave soft tissue outline in the edentulous ridge mucosa. However, at times floss cannot pass through the center of the pontic, especially in the anterior teeth area, where the distance from the top of the papilla to the labial gingival margin is longer than in the posterior teeth area. (The cementoenamel junction is more curved in anterior teeth, and there is more convexity as compared with posterior teeth area). The modified ovate pontic was developed to circumvent this problem. This pontic is less convex and often requires little or no ridge augmentation.

The other advantage of modified ovate pontic is lateral tissue support and food deflection. The axial contours of the pontic form a deflection ridge to prevent food impaction yet remain subtle enough to provide a massaging action to the gingival.

According to studies conducted by Nicola Ursula et al in 2002 on the histologic features of the tissue surrounding the ovate pontic, it was suggested that long-term mucosal health can be maintained with an ovate pontic design, provided that the infrapontic area is carefully adapted and regularly cleaned.

In contrast to the requirements for pontics, which suggest the importance of pressure-free contact over a small area, the ovate pontic comes in contact with a larger area of the underlying soft tissue and applies very light pressure. The authors suggested that “hyper pressure” resulted in a thinner epithelium with shorter rete pegs when compared with the adjacent uncovered mucosa. In the study the adequate adaptation of the ovate pontic to the alveolar ridge mucosa with daily hygiene management of the infra-pontic area did not cause substantial changes with regard to the height of the epithelium and the rete pegs.

The epithelium in the pontic site was always identified as keratinized, but the keratin layer itself was thinner than in the reference area. The keratin layer contributes to the protection of the masticatory mucosa against mechanical and/or microbial insult. The enhanced volume of inflammatory cells in the subepithelial zone of pontic sites, as compared with control sites, may in part be explained by this thinner keratin layer.

The need for oral hygiene procedures was stressed upon as it has a direct correlation to the health of the tissue. Liu5 noted that with the modified ovate pontic, 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 the ovate pontic and hence the floss can be brought into intimate contact with the tissue-contacting surface.

CONCLUSION :

It can be concluded that for an esthetic and functional restoration in anterior esthetic areas, where ridge augmentation can be avoided, a modified ovate pontic is a viable option for the esthetic solutions. The patient has the advantage of practicing the required oral hygiene habits during the provisional phase which will hopefully result in the long-term success of the prosthesis.

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