Pontic and pontic designs

Pontics in fixed denture prosthesis

1. PONTIC AND PONTIC DESIGNS Presented by: Dr. Rajvi Nahar 2 nd year post graduate student

2. CONTENTS Introduction Successful pontic design Pretreatment assessment Residual ridge contour Siebert’s classification Surgical modification Various graft techniques Gingival architecture preservation Ideal requirements of pontics Pontic design classification Pontic design considerations Conclusion References

3. Introduction Pontics are the artificial teeth of a partial fixed dental prosthesis (FDP) that replace missing natural teeth, restoring function and appearance. To design a pontic that meets hygienic requirements and prevents irritation of the residual ridge, particular attention must be given to the form and shape of the gingival surface. The pontic must be carefully designed and fabricated not only to facilitate plaque control of the tissue surface and around the adjacent abutment teeth but also to adjust to the existing occlusal conditions.

4. In addition to these biologic considerations, pontic design must incorporate mechanical principles for strength and longevity, as well as esthetic principles for satisfactory appearance of the replacement teeth. 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 of gold, porcelain, or acrylic.

5. Definitions ACCORDING TO GPT-8 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. ACCORDING TO TYLMAN The suspended member of a fixed partial denture which replaces the lost natural tooth, restores function and occupies the space of the missing tooth. The Glossary of Prosthodontic Terms. The Journal of Prosthetic Dentistry. 2005;94(1):10-92. Tylman SMalone W. Tylman's Theory and practice of fixed prosthodontics. 8th ed.

6. Successful pontic design

7. PRETREATMENT ASSESSMENT I] PONTIC SPACE: One function of FPD is to prevent tilting or drifting of the adjacent teeth into the edentulous space. Drifting / tilting Reduced pontic space Difficulty in fabricating pontic

8. Esthetic Zone Orthodontic alignment Abutment modification with complete coverage retainers Unaesthetic Zone Overly small pontics are unacceptable Trap food Difficult to clean Careful diagnostic waxing To determine most appropriate treatment Increasing the proximal contours of adjacent teeth  better than  small pontic .  No functional/ esthetic deficit  Maintain the space without any prosthodontic intervention

9. The edentulous ridge contour and topography should be carefully evaluated during the treatment planning phase. Features of Ideal Ridge Contour: Smooth and regular surface of attached gingiva Facilitate maintenance of plaque-free environment Sufficient height and width Mimic adjacent tooth contours Appear to emerge from the ridge Facially, free of frenal attachment II] RESIDUAL RIDGE CONTOUR

10. Loss of residual ridge contour: Unesthetic open gingival embrasures “BLACK TRIANGLES” Food impaction Percolation of saliva during speech

11. SIEBERT’S CLASSIFICATION OF RESIDUAL RIDGE DEFORMITIES : A, Class O - no defect. B, Class I defect - Faciolingual loss of tissue width with normal ridge height. C, Class II defect - Loss of ridge height with normal ridge width. D, Class III defect - a combination of loss in both dimensions.

12. STATISTICS 91% residual ridge deformities  Anterior tooth loss  Majority are class III defects  Majority of patients with class II & class III defects  Unsatisfied with esthetics  Pre-prosthetic surgery Ridge augmentation

13. SURGICAL MODIFICATION Ridge augmentation with hard tissue grafts is not indicated unless it is to receive an implant. Class I Defects: Infrequent Not esthetically challenging Soft tissue procedures recommended to improve width of the defect.

14. SURGICAL CORRECTION I] THE ROLL TECHNIQUE FOR SOFT TISSUE RIDGE AUGMENTATION:

15. II] THE POUCH TECHNIQUE FOR SOFT TISSUE RIDGE AUGMENTATION:

16. CLASS II & CLASS III DEFECTS I] INTERPOSITIONAL GRAFT: Variation of pouch technique Augmentation of ridge height & width

17. II] ONLAY GRAFT

18. GINGIVAL ARCHITECTURE PRESERVATION Following tooth extraction- BUCCAL PLATE- Horizontal defect Degree of RRR- 3-5mm- 6months and 50% width- 12months Resulting deformities - unpredictable & not inevitable Immediate restorative and periodontal intervention Conditioning the extraction site Providing matrix for healing

19. Interim restoration Atraumatic extraction Scalloped architecture of interproximal bone If bone levels are compromised : Allograft materials Hydroxyapatite Tricalcium phosphate Freeze dried bone Can be grafted into the sockets

20. The tissue side of the pontic should be: an ovate form - 2.5 mm apical to the facial free gingival margin The pontic causes tissue blanching as it supports the papillae and facial/palatal gingiva. The tissue side of the pontic must conform to within 1 mm of the interproximal and facial bone contour to act as a template for healing. After approximately 1 month of healing, oral hygiene access is improved by recontouring the pontic to provide 1 to 1.5 mm of relief from the tissue.

21. Orthodontic extrusion Avoids ridge augmentation and gain vertical ridge height However, Additional time and expense of orthodontic treatment, as well as previous endodontic treatment is necessary.

22. GOOD AESTHETICS COLOR STABILITY HYGIENE NON-IRRITANT MAINTENANCE OF SPEECH MAINTENANCE OF TOOTH RELATIONSHIPS IDEAL REQUIREMENTS OF PONTIC

23. PONTIC DESIGN CLASSIFICATION According to Rosenstiel A] MUCOSAL CONTACT: Ridge lap Modified ridge lap Ovate Conical B) NO MUCOSAL CONTACT Sanitary (hygienic) Modified sanitary (hygienic)

24. Depending on shape of surface contacting the ridge ( Tylmann ) Sanitary Modified sanitary Spheroidal Saddle Ridge lap Modified ridge lap Ovate

25. According to the form (Johnston) Sanitary or Hygenic Anatomic type Based on materials used Metal and porcelain veneered Metal and resin veneered All metal pontic All ceramic pontic

26. According to methods of fabrication Custom made pontic Prefabricated pontic Trupontic Interchangeable facing Sanitary pontic Pin-facing pontic Modified pin-facing pontic Reverse pin-facing pontic Harmony pontic Porelain fused to metal pontic Prefabricated custom modified

27. PONTIC SELECTION Pontic selection depends primarily on esthetics and oral hygiene. ANTERIOR REGION POSTERIOR REGION

28. ANTERIOR PONTIC DESIGN A correctly placed anterior pontic should have All surfaces convex, smooth and properly finished. Contact with the labial mucosa should be minimal (pin point) and pressure free (lap facing). The lingual contour should be in harmony with adjacent teeth or pontics . Pontic- residual ridge relationship: A research report. Stein RS, J Prosthet Dent 1966; 16: 251

29. POSTERIOR PONTIC DESIGN A correctly designed pontic should have All surfaces convex, smooth and properly finished. Contact with the buccal contiguous slopes should be minimal (pin point) and pressure free (modified ridge lap). Occlusal table must be in functional harmony with the occlusion of all of the teeth Buccal and lingual shunting mechanism should conform to those of the adjacent teeth. The overall length of buccal surface should be equal to that of the adjacent abutments or pontics . Pontic- residual ridge relationship: A research report. Stein RS, J Prosthet Dent 1966; 16: 251

30. PRE-FABRICATED PONTIC FACINGS These are commercially available porcelain pontics which can be altered by the dentist and reglazed if necessary. These include: a) Trupontic – A horizontal tubular slot in the center of the lingual surface of the facing. b) Interchangeable facings/flat back facing– Manufactured with vertical slot running down the flat lingual surface, this facing is retained with a lug which engages the retention slot.

31. c)Sanitary facing –flat occlusal surface and a slot on the proximal surface to fit into the metal projections made in the FDP d) Pin facing – A flat lingual facing with two horizontal pins for retention.

32. e) Modified Pin Facing- Facing is modified by adding porcelain to lingual gingival area of a pin facing f)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 and multiple precision pin holes are drilled into the lingual surface

33. g) Harmony facing – This facing is supplied with an uncontoured porcelain gingival surface and usually two retentive pins on the flat lingual side. i ) Pontips : Convex gingival surface having pinpoint tissue contact and attached to the backing occlusally with retentive pins. h) Porcelain fused to metal facing- Facing consists of a metal core over which porcelain is fused.

34. SANITARY OR HYGIENIC PONTIC Zero tissue contact Occlusal-gingival thickness should be atleast 3mm Convex mesiodistally and faciolingually Space beneath the pontic – 2mm ( Rosenstiel) - 3 mm ( Tylman ) Adequate space for cleaning Mandibular molars

35. Modified sanitary pontic Gingival portion is shaped like a concave archway mesiodistally between the retainers and convex faciolingually . Allows increased connector size while decreasing the stress concentrated in the pontic and connectors. Recommended for mandibular posteriors

36. ADVANTAGES: Deflection is diminished in the center of the pontic . Food retention impossible. Makes it easy for the patient to remove debris. Added bulk at the connectors: Stress reduced significantly. Prevents undue flexure of fixed prosthesis. Reshapes and reinforces critical solder joint region.

37. CONICAL PONTIC egg-shaped, bullet-shaped, or heart-shaped Convex with only one point of contact at the center of the residual ridge. recommended for the replacement of mandibular posterior teeth where esthetics is a lesser concern.

38. The facial and lingual contours are dependent on width of the residual ridge; A knife-edged residual ridge necessitates flatter contours with a narrow tissue contact area. Unsuitable for broad residual ridges

39. OVATE PONTIC most esthetically appealing Its convex tissue surface resides in a soft tissue depression or hollow in the residual ridge, which makes it appear that a tooth is literally emerging from the gingiva

40. Socket-preservation techniques should be performed at the time of extraction to create the tissue recess from which the ovate pontic form will emerge. For a preexisting residual ridge, soft tissue surgical augmentation is typically required. When an adequate volume of ridge tissue is established, a socket depression is sculpted into the ridge with surgical diamonds or electrosurgery.

41. Modified ovate pontic The modified ovate pontic possess an ovate form with the apex positioned more facially on the residual ridge rather than at the crest of the ridge. Used where horizontal ridge width is not sufficient.

42. SADDLE PONTIC OR RIDGE LAP PONTIC Concave fitting surface that overlaps the residual ridge buccolingually, simulates the contours and emergence profile of the missing tooth on both sides of the residual ridge. The contact with the ridge extends beyond the midline of the edentulous ridge.

43. Saddle or ridge lap designs should be avoided The concave gingival surface of the pontic is not accessible to cleaning with dental floss>>>>plaque accumulation>>>>> tissue inflammation.

44. MODIFIED RIDGE LAP This design gives the illusion of a tooth, but it possesses all or nearly all-convex surface for ease of cleaning. The lingual surface - slight deflection contour – prevents food impaction and minimize plaque accumulation. Ridge contact must extend no further lingually than the mid-line of the edentulous ridge.

45. The contour of the tissue contacting area of the pontic should be convex, this design with a porcelain veneer is most commonly used pontic design in the appearance zone for both maxillary and mandibular FPD. Tissue contact should resemble a letter T whose vertical arm ends at the crest of the ridge. Most common pontic form used in areas of high visibility--- maxillary and mandibular anterior teeth and maxillary premolars and first molars

46. Cantilever FDPs in which only one side of the pontic is attached to a retainer are referred to as cantilevered. long-term prognosis of the single abutment cantilever is poor. Forces are best tolerated by the periodontal supporting structures when directed in the long axes of the teeth. A cantilever induces lateral forces on the supporting tissues, which may be harmful and lead to tipping, rotation, or drifting of the abutment

47. When multiple missing teeth are replaced, cantilever FDPs have considerable application. The harmful tipping forces are resisted by multiple abutment teeth, and movement of the abutments is unlikely. Cantilevers are also successfully used with implant-supported prostheses.

48. Summary

49. BIOLOGIC CONSIDERATIONS The biologic principles of pontic design pertain to the maintenance and preservation of the residual ridge, abutment and opposing teeth, and supporting tissue. Factors of specific influence are, Ridge pontic contact Amenability to oral hygiene Direction of occlusal forces

50. RIDGE CONTACT Pressure free contact between the pontic and the underlying tissue When a pontic rests on mucosa, some ulcerations may appear as a result of the normal movement of the mucosa in contact with the pontic . Positive ridge pressure ( hyperpressure ) may be caused by excessive scraping of the ridge area on the definitive cast

51.  If the pontic encroaches on the unattached mucosa an ulcer will form.  Hence the tip must be restricted to the keratinised gingiva itself

52. SUBPONTIC OSSEOUS HYPERPLASIA: First described by Calman (1971) as painless, slow growing lesion on edentulous ridge beneath FPD treatment due to following reasons: Functional stresses or stimuli:- Photoelastic theory states that 1 st molar region is subjected to stresses during opening and closing loading. Mild chronic irritation. Bone under compression develops negative electric potential, that promote osteogenesis associated with bone growth. Treatment: Removal of FPD, surgical resection, recontouring of alveolar ridge.

53. Pontic- residual ridge relationship: A research report To determine the frequency and the nature of tissue reaction of underlying the residual ridge mucosa to specific pontic designs and various materials used in pontic constructions. Upon removal of pontics , inflammatory reactions of the underlying mucosa were found under 95 per cent of the pontics . The ideal design was shown to be a “modified ridge lap” in the posterior region and a “lap facing” in the anterior region, with a pinpoint contact on the facial contiguous slope of the residual ridge. The ideal design should include surface smoothness and a fine finish A successful artificial tooth replacement was characterized by a healthy tissue response with the appearance of a lack of contact between the residual ridge and undersurface of the pontic .

54. POST HYGIENE INSTRUCTIONS: The chief reason for ridge irritation is the toxins released from microbial plaque, which accumulates between the gingival surfaces of the pontic and residual ridge causing inflammation and calculus formation. The gingival embrasures of the pontic should be wide open to allow the patient easy access for cleaning and the contact between the pontic tissue must allow the passage of floss from one retainer to another.

55. Triphodakis (1990) showed in his study that tissues under a pontic can be maintained in an inflammation-free condition if the patient flosses at least once a day there will be imprint or foot print of the pontic on the ridge without inflammation. Devies such as proxy brushes, super floss and dental floss are highly recommended.

56. PONTIC MATERIAL Should provide good esthetic results, biocompatibility, rigidity, and strength to withstand occlusal forces; and longevity. Occlusal contacts should not fall on the junction between metal and porcelain during centric or eccentric tooth contacts, nor should a metal ceramic junction occur in contact with the residual ridge on the gingival surface of the pontic . Investigations into the biocompatibility of materials used to fabricate pontics have centered on two factors : The effect of the materials and The effects of surface adherence.

57. Well-polished gold is smoother, less prone to corrosion, and less retentive of plaque than an unpolished or porous casting. For easier plaque removal and biocompatibility, the tissue surface of the pontic should be made in glazed porcelain However, ceramic tissue contact may be contraindicated in edentulous areas where there is minimal distance between the residual ridge and the occlusal table.

58. OCCLUSAL FORCES Reducing the buccolingual width of the pontic by as much as 30% 12% increase in chewing efficiency can be expected from a one third reduction of pontic width. Narrowing the occlusal table may actually impede the development of a harmonious and stable occlusal relationship Difficulties in plaque control and improper cheek support. Pontics with normal occlusal widths (at least on the occlusal third) are generally recommended. One exception is if the residual alveolar ridge has collapsed buccolingually. Reducing pontic width may then be desired, thereby lessening the lingual contour and facilitating plaque control measures.

59. MECHANICAL CONSIDERATIONS Mechanical problems may be caused by improper choice of materials poor frame work design poor tooth preparation poor occlusion. Therefore, evaluating the likely forces on a pontic and designing accordingly are important. For example, a strong all metal pontic may be needed in high stress situations rather than a metal ceramic pontic which would be more susceptible to fracture.

60. Defective bonding Cervical fracture Occlusal fracture MECHANICAL FAILURES

61. METAL CERAMIC PONTICS A well fabricated metal ceramic pontic is strong, easy to keep clean, and looks natural. The framework must provide a uniform veneer of porcelain (approximately 1.2 mm). The metal surfaces to be veneered must be smooth and free of pits Sharp angles on the veneering area should be rounded. Occlusal centric contacts must be placed at least 1.5 mm away from the metal-porcelain junction

62. RESIN-VENEERED PONTICS Resistance to abrasion is lower than enamel or porcelain, no chemical bond existed between the resin and the metal framework, Continuous dimensional change of the veneers often caused leakage at the metal-resin interface, with subsequent discoloration of the restoration. New-generation indirect resins High flexural strength, minimal polymerization shrinkage, and wear rates comparable with those of tooth enamel

63. FIBER-REINFORCED COMPOSITE RESIN PONTICS Composite resins can be used in fixed partial dentures without a metal substructure. A substructure matrix of impregnated glass or polymer fiber provides structural strength. Excellent marginal adaptation and esthetics

64. SUMMARY

65. ESTHETIC CONSIDERATIONS These are situations which require a more conservative approach. The patient’s inability to undergo surgery or an unwillingness to consider it will force the considerations of alternative form. If bridges have 2 or more pontic used to fill the edentulous space, black triangles can be very unaesthetic; they collect plaque, interfere with passage of floss, and reduce the rigidity of the pontic span. Pink porcelain can be added to gingival position in the embrasure area of the pontic ; although the shade rarely matches with the hue of the patient the gingival extension must be supported by metal framework. Elimination of interpontic embrasure in a multitooth pontic may limit or eliminate soft tissue proliferation.

66. THE GINGIVAL INTERFACE An esthetically successful pontic will replicate the form, contours, incisal edge, gingival and incisal embrasures, and color of adjacent teeth. The pontic’s simulation of a natural tooth is most often betrayed at the tissue pontic interface. Special attention should be paid to the contour of the labial surface as it approaches the pontic -tissue junction to achieve a “natural” appearance. If the original tooth contour were followed, the pontic would look unnaturally long incisogingivally

67. The modified ridge-lap pontic is recommended for most anterior situations; it compensates for lost buccolingual width in the residual ridge by overlapping what remains However, when appearance is of utmost concern, the ovate pontic , used in conjunction with alveolar preservation or soft tissue ridge augmentation- provide an appearance at gingival interface just like adjacent natural teeth.

68. Special care must be taken when studying where shadows fall around natural teeth, particularly around the gingival margin. If a pontic is poorly adapted to the residual ridge, there will be an unnatural shadow in the cervical area >> spoils the illusion of a natural tooth. Recesses occurring at the gingival interface collect food debris, further betraying the illusion of a natural tooth.

69. INCISOGINGIVAL LENGTH Ridge resorption will make a pontic look too long in the cervical region. An abnormal labiolingual position or cervical contour, however, is not immediately obvious. This fact can be used to produce a pontic of good appearance by recontouring the gingival half of the labial surface

70. In areas where tooth loss is accompanied by excessive loss of alveolar bone, the pontic is shaped to simulate a normal crown and root with emphasis on the cementoenamel junction. The root can be stained to simulate exposed dentin

71. GINGIVA-COLORED CERAMICS If augmentative measures are contraindicated or undesirable, small alveolar deficiencies and missing papillae can be reconstructed by restorative measures. The exact shade of the gingiva has to be established with special gingival shade guides. The basal surface must demonstrate a convex shape similar to the ovate pontic designs for the dental floss to establish tight contact with all the surface areas. Daniel E , H Spiekermann : A review of esthetic pontic design options. Quintessence Int 2002;33:736-746

72. ALL-CERAMIC GINGIVAL MASKS Separately fabricated ceramic gingival masks can be used to make subsequent adjustments in permanently placed restorations. This method is particularly suitable for patients with a local alveolar ridge defect that has not been corrected by augmentation of the soft tissue. Daniel E , H Spiekermann : A review of esthetic pontic design options. Quintessence Int 2002;33:736-746

73. MESIODISTAL WIDTH Frequently, the space available for a pontic will be greater or smaller than the width of the contra lateral tooth. If possible, such a discrepancy should be corrected by orthodontic treatment. If this is not possible, an acceptable appearance may be obtained by incorporating visual perception principles into the pontic design.

74. The features of the contra lateral tooth should be duplicated as precisely as possible in the pontic , and the space discrepancy can be compensated by altering the shape of the proximal areas. The retainers and the pontic can be proportioned to minimize the discrepancy. In this situation a diagnostic waxing procedure will help solve a challenging restorative problem.

75. Space discrepancy presents less of a problem when posterior teeth are being replaced because their distal halves are not normally visible from the front. Discrepancy here can be managed by duplicating the visible mesial half of the tooth and adjusting the size of the distal half.

76. Fiber -reinforced Composite Fixed Dental Prostheses with Various Pontics PURPOSE: To evaluate the load-bearing capacities of fiber-reinforced composite (FRC) fixed dental prostheses (FDP) with pontics of various materials and thicknesses. MATERIALS: 72 FDPs with frameworks made of continuous unidirectional glass fibers ( everStick C&B) were fabricated. Three different pontic materials were used: glass ceramics, polymer denture teeth, and composite resin. The FDPs were divided into 3 categories based on the occlusal thicknesses of the pontics (2.5 mm, 3.2 mm, and 4.0 mm).

77. CONCLUSION: By increasing the occlusal thickness of the pontic , the loadbearing capacity of the FRC FDPs may be increased. The highest load-bearing capacity was obtained with 4.0 mm thickness in the ceramic pontic . However, with thinner pontics , polymer denture teeth and composite pontics resulted in higher load-bearing values Fiber-reinforced Composite Fixed Dental Prostheses with Various Pontics The Journal of Adhesive Dentistry2014Vol 16, No 2

78. PREFABRICATED WAX PONTICS Advantages: Without collar Reduced occlusal depths Reinforced approximal surfaces Perfect scraping and modelling characteristics

79. Primary use: Temporary Bridges Plastic to fabricate quick and economical temporary bridges. Wear-resistant, vacuum processed synthetic resin Special lingual channel ensures pontic locks into the plastic

80. Conclusion Designs that allow easy plaque control are especially important to a pontic’s long term success. Minimizing tissue contact by maximizing the convexity of the pontic’s gingival surface is essential. Special consideration is also needed to create a design that combines easy maintenance with natural appearance and adequate mechanical strength. When the appropriate design has been selected, it must be accurately conveyed to the dental technician.

81. References Rosenstiel S F et al : Contemporary Fixed Prosthodontics, 4th edn Missouri, Mosby Inc, pg 513 Shillingburg H T et al : Fundamentals of fixed prosthodontics, ed 4, Chicago , Quintessence Publishing, pg 485 Tylman SMalone W. Tylman's Theory and practice of fixed prosthodontics. 8th ed. The Glossary of Prosthodontic Terms. The Journal of Prosthetic Dentistry. 2005;94(1):10-92. Pontic- residual ridge relationship: A research report. Stein RS, J Prosthet Dent 1966; 16: 251 Daniel E , H Spiekermann : A review of esthetic pontic design options. Quintessence Int 2002;33:736-746 Fiber-reinforced Composite Fixed Dental Prostheses with Various Pontics The Journal of Adhesive Dentistry2014Vol 16, No 2 Korman R. Enhancing Esthetics with a Fixed Prosthesis Utilizing an Innovative Pontic Design and Periodontal Plastic Surgery. Journal of Esthetic and Restorative Dentistry. 2014;27(1):13-28.

82. Thank you