March 25, 2014
Authors: Sang K Jun CDT Yewon Dental Laboratory Monterey, CA Heinz Klein DMD Private Practice. Campbell, CA Lois Lagier DDS Private Practice. Monterey, CA
Tissue colored porcelain can be used to create esthetic implant-supported restorations when bone and gingival tissues are deficient and surgical replacement of such tissues is not possible. An important consideration when designing such prosthetics is hygiene and maintenance. It is essential to create smooth and cleansable gingival contacts that will promote long-term hard and soft tissue health. Key Word Implant. CAD/CAM. Soft Tissue. Cleansing. Low Fusing.
The use of dental implants to restore partially edentulous dentitions1 has become standard practice in most modern dental practices today. Many different technological advances have combined to make implant dentistry much more predictable, especially when restoring teeth in the esthetic zone.
Cone Beam Computerized Tomography (CBCT) facilitates digital surgical treatment planning, which allows an accurate preview of implant placement2. The use of this same digital imaging information by the restorative team (restorative dentist and laboratory technician) and surgical team (periodontist and oral surgeon) provides a valuable resource to assess and identify specific details that must be considered prior to starting treatment.
Multiple modern esthetic dental materials now exist, such as CAD/CAM milled single tooth zirconia to full round fixed denture with artificial gingiva and pressed or milled Lithium Disilicate ( E-Max Ivoclar Vivident. Amherst, NY ) , as well as several different techniques that utilize those same materials to create final restorations.
Better porcelain shades, including those that mimic gingival tissue are available. These can be used to effectively and esthetically replace gingival soft tissue that could not be restored surgically3. Whether the restorations are handcrafted by a ceramist, or created using CAD/CAM technology in combination with milling, the final result must be hygienic, and allow for proper maintenance of the prosthesis by the patient at home.
CASE NUMBER ONE
A 63 year-old female patient presented with missing maxillary central incisors. The edentulous space had been present for over ten years and had been restored with a maxillary acrylic partial denture (Figures 1 and 2.) The patient’s chief complaints were the inconvenience of wearing the removable appliance and the compromised esthetic appearance.
The patient was referred to a periodontist for evaluation and a CBCT was requested to evaluate available bone and virtual implant placement (Figure 3.) Significant facial bone loss and loss of papillae were identified. The remaining alveolar ridge was thin. Bone augmentation was accomplished and allowed to heal for four months. Two implants were placed and healing cuffs positioned at tissue height. After four months of healing, a fixture level impression was taken with customized Polyetheretherketone (PEEK – BioHorizon, Birmingham, AL) abutments in place (Figure 4.)
The impressions were sent to the dental laboratory for fabrication of a screw-retained implant-supported temporary restoration. Pink composite resin was added as necessary to create appropriate contours to sculpt the gingival tissues and obtain correct gingival architecture4 (Figure 5.)
Following gingival shaping, fixture level final impressions were obtained and sent to the dental laboratory for creation of the final restoration. The maxillary impression was poured with and without a soft tissue cast (Figures 6 and 7.) The restorative team elected to utilize the solid stone model. Because the temporary restorations had created well-sculpted soft tissue architecture, the soft tissue restorative goal was to prevent compression of the gingival tissue5, and avoid potential recession or pathology.
The laboratory technician created a framework designed to support the veneering porcelain6 (Figure 8.) Gold coat ( Gramm Technology. Woodbridge, VA ) was applied after first layer of opaque and fired framework (Figure 9.) then second layers of opaque masking porcelain were applied and fired (Figure 10.)
A bright opacious dentin porcelain ( Creation. Jensen Dental. North Haven, CT ) layer was then applied to the height of contours to slightly increase the value; which would later be offset and lowered by applying the many layers of enamel and translucent porcelain (Figure 11.)
Appropriate opaque dentin porcelain was applied in the incisal one-half of the restoration, and mostly vertical depressions or grooves created for the internal reflection of light (Figure 12.)
A thin layer of clear (translucent) porcelain was applied between grooves in the stacked porcelain to trap the light (Figure 13.)
Slightly darker dentin porcelain was applied in the gingival area and the porcelain was built to full contour (Figure 14.) Pink gingival-colored porcelain was then applied to the interproximal areas to create the missing soft tissue (Figure 15.)
Porcelain was cut back to create internal characterizations and space for the enamel and translucent porcelain layer (Figure 16.) Select internal stain and characterizing porcelains were placed, and different colors of enamel porcelain applied to create the illusion of depth (Figures 17 and 18.)
The first body firing was accomplished (Figure 19) and additional stains and colored porcelain were added to further enhance the natural appearance. White enamel porcelain was added to create a “high value” zone often found in natural dentitions. Pink gingival porcelain was added where required (Figure 20.)
Translucent enamel layer was created by alternating different colors of translucent porcelain to mimic the blending and contrast found in nature (Figure 21.)
The second body firing was completed, and all necessary contour adjustments were done prior to bisque bake try-in (Figure 22.)
The splinted restoration was temporarily attached to the supporting implants, and the shape, contours, color, and cleansability were evaluated (Figures 23 and 24.)
After final contour adjustments were made, low fusing porcelain powder was applied to the gingival tissue contact areas and fired at the normal glazing temperature, creating a very smooth, over-glazed surface. (Figures 25, 26 and 27.) The purpose of this over-glazed gingival surface layer was to minimize plaque retention and tissue irritation7.
By utilizing correct design principals, understanding the materials involved, establishing proper communication, facilitating good patient hygiene, and following through with routine dental evaluation visits, restoration longevity and gingival health was expected (Figures 28, 29, 30, 31 and 32.)
CASE NUMBER TWO
A 63 year-old female patient presented with bone loss and soft tissue recession due to prolonged periodontal disease. Surgical bone grafting was accomplished by a maxillofacial surgeon with limited success due to patient’s health condition. Dental implants were placed into the compromised site (Figure 33.)
When compared to the contralateral tissue and dentition, it was observed that the deficient tissue contours would significantly compromise esthetics (Figure 34.)
The same technique and materials (as in Case Number One) were utilized to create gingival soft tissues in the porcelain (Figure 35.) Proper design for cleansability, combined with an over-glazed low fusing porcelain contact area created the best possible conditions for soft tissue health (Figures 36 and 37.)
A happy patient (Figure 38.)
The demand and requirement for implant-supported restorations is greater than ever. Constantly improving technologies such as CBCT continue to help clinicians to treatment plan and place implants accurately. Even available technology cannot replace bone and soft tissue contours when they are inadequate. Tissue colored porcelain, using designs and techniques that are hygienic and cleansable, offer a useful esthetic alternative. Effective communication between clinicians and laboratory technicians is essential to design and plan such cases.
Reference: 1. Jemt T, Lekholm U, Adell R. Osseointegrated implants in the treatment of partially edentulous patients: a preliminary study on 876 consecutively placed fixtures. Int J Oral Maxillofacial Implants 1989;4:211-217. 2.Kourtis S. Skondra E. Roussou I. Presurgical planning in implant restorations: correct interpretation of cone-beam computed tomography for improved imagingJ Esthet Restor Dent. 2012 Oct;24(5):321-32 3 JKourtis S, Kokkinos K, Roussou V. Predicting the Final Result in Implant-Supported Fixed Restorations for Completely Edentulous Patients. Esthet Restor Dent. 2013 Dec 17. doi: 4. Parpaiola A, Sbricoli L, Guazzo R, Bressan E, Lops D. Managing the Peri-implant Mucosa: A Clinically Reliable Method for Optimizing Soft Tissue Contours and Emergence Profile. Journal of Esthetic & Restorative Dentistry 2013;25:317-23 5. Lindhe J. Clinical periodontology and implant dentistry. 5th ed. Malden (MA): Blackwell Munksgaard; 2006. 6. Straussberg G, Katz G, Kuwata M Design of gold supporting structures for fused porcelain restorations. J Prosthet Dent 1966;16:928-36. 7. Cavazos E. Tissue response to fixed partial denture pontics. J Prosthet Dent 1968;20:143-53. Figure 1. Removable Partial Denture for tooth # 8 and 9. 2. Edentulous space of tooth # 8 and 9. 3. CBCT images of patient. 4. Customized PEEK abutments in place for fixture level impression for temporary restorations. 5. Screw retained temporary restorations with pink colored acrylic. 6. A model of final impression with soft tissue cast. 7. A stone model of final impression. 8. Metal substructure for veneering porcelain. 9. Gold coats were applied after 1st opaque. 10. 2nd layer of opaque was applied and fied. 11.Bright opaque dentin were applied on heights of contour to prevent low value on final restoration. 12. Appropriate opaque dentin was applied incisal ½ then indentations were created to reflect the lights. 13. Clear translucents were filled in between indentations to trap the lights. 14. Dentin is build to full contour. 15. Pink porcelain was build to where it is needed. 16. Cut back was done to create space for internal characterization, enamel and translucent layers. 17. Internal characterization and stain were done and different optical density of enamel were filled and layered. 18. Enamel layer was completed. 19. First firing of restorations. 20. Added internal stain and characterizations were done and whitish enamel was applied middle part of restorations for high value zone. 21. Translucent layer was completed and pink porcelains were added. 22. Second firing was done and ready for bisque bake try-in. 23. Bisque bake try-in. 24. Confirming access for cleansing. 25. Facial view of final restorations. 26. Low fusing porcelain was applied and fired on regular porcelain glazing cycle. 27. Final restorations on stone model. 28. Insertion of final restorations. 29. Screw retained implant supported restoration. 30. Right lateral view of 6 month post-op 31. Left lateral view of 6 month post-op. 32. Facial view of 6 month post-op. 33. Positions of implants and customized cast metal abutments. 34. Custom abutments in inter-oral place. 35. Insertion of final restorations. 36. Facial view of final restorations at time of cementation. 37. 1 year post-op. 38. Aesthetically very satisfied happy patient.