CHAPTER 7

Implant-supported restorations

Anterior regions

2.7.1 Implant-supported four-unit fixed dental prosthesis (FDP)

Posterior regions

2.7.2 Implant-supported three-unit fixed dental prosthesis (FDP)

2.7.3 Implant-supported fixed dental prosthesis with mesial cantilever (FDP)

2.7.4 Implant-supported fixed dental prostheses (FDPs)

Complex situations

2.7.5 Full-arch implant-supported fixed restoration with pink ceramics (FDP)

2.7.1 Implant-supported four-unit fixed dental prosthesis (FDP)

■ Anterior regions, titanium-resin base, and restoration (semi opaque zirconia)

■ Four-unit anterior implant fixed dental prosthesis (FDP) guided surgery, and full digital workflow

This first sequence shows the replacement of a failing four-unit anterior FDP due to fractured lateral incisors by means of diameter-reduced implants (bone level 3.3 mm) and titanium-resin-base abutments, in combination with semi-opaque high-strength zirconia via the application of a digital workflow.

Assessment and treatment planning

A 49-year-old male patient presented himself at the clinic seeking a replacement of his failing four-unit anterior porcelain-fused-to-metal (PFM) FDP. The patient was healthy, a non-smoker, and did not take any medication. The old PFM FDP was debonded some days before as he was abroad, and the patient managed the situation by seeing a dentist for an emergency recementation of the FDP. The treating dentist, however, told him that most likely this will not be a long-term solution and he should see a specialist in his home city.

The abutment teeth had to be extracted because of their epigingival fracture and due to a periapical radiolucency indicating a perio-endo problem.

Due to the position in the arch and the size of the restoration, it was planned to place two diameter-reduced bone-level implants (Bone Level NC, Straumann, Basel, Switzerland) with a diameter of 3.3 mm, applying guided surgery, and including guided bone regeneration (GBR) if needed.

After successful osseointegration, the implants were restored with a semi opaque zirconia FDP (Lava Plus, 3M, Seefeld, Germany) on a titanium-resin bases (Vario-Base, Straumann).

To increase efficiency it was planned to acquire an optical impression and follow the complete digital workflow from diagnostics to the final computer-aided design/computer-aided manufacturing (CAD/CAM) fabricated restoration (Fig 2-7-1).

Tooth extraction and ridge preservation

The remaining roots of the fractured lateral incisors were extracted and a xenogeneic bone substitute in combination with a punch graft from the palate was used to perform a ridge preservation procedure (Fig 2-7-2).

A provisional removable prosthesis was prefabricated in the dental laboratory and could be delivered to the patient on the day of extraction. It had to be slightly adapted and reduced in the base before it could be delivered and finally replace the missing teeth. As the possibility for an adaptation was foreseen, the provisional was fabricated with a small buccal flange to better compensate potential adjustments (Fig 2-7-3).

Diagnostics and virtual mock-up

The patient’s main wish was the replacement of his failing FDP. Additionally, during the last few years he began to realize the unesthetic appearance of his existing restoration, as it was very opaque, revealed metal margins, and was of an artificial shape. He wanted to be Part of the diagnostic process to help develop the final outline of his new restoration. Initially, all corrections were performed digitally by means of an image editing software (Photoshop Elements; Adobe Systems, San Jose, CA, USA) to visualize the patient’s treatment. Thereafter, all the planned changes were transferred and visualized in a CAD software (Exocad, Darmstadt, Germany). The software was used to project a virtual mock-up into twodimensional pictures of his dentition and with this superimposition allow him to better understand the potential changes.

Together with the patient, various suggestions were worked out, discussed, and then saved as a file. After the patient opted for a visualized design, the virtual mock-up was transformed into a provisional (Fig 2-7-4).

Guided implant placement

On the day of implant placement, the patient was premedicated with 1500 mg amoxicillin and 600 mg ibuprofen. A flapless approach was chosen to reduce morbidity for the patient and with the aid of a surgical stent (SMOP, Swissmeda, Zurich, Switzerland) two diameterreduced bone-level implants (Bone Level NC 3.3 mm, Straumann) were placed in the area of the lateral incisors. For both implants a good primary stability in a correct prosthetic position/axis could be achieved and finally the impacts were covered with small closure screws.

After the suturing the implants were left for submucosal healing for 8–10 weeks. Antibiotics (amoxicillin 3 × 750 mg for 5 days), painkillers (600 mg ibuprofen if needed), and chlorhexidine mouth rinse (0.2%) were prescribed. The sutures were removed 10 days after implant placement (Fig 2-7-5 and Fig 2-7-6).

Soft tissue augmentation

To augment the soft tissue deficiency in the area around the implant positions, two connective tissue grafts were harvested in the palatal area of the second quadrant and carefully placed (Fig 2-7-7).

Abutment connection

The healing period was uneventful and 3 months after surgery the clinical examination revealed healthy tissues. At this time point, the abutment connection was performed under local anesthesia. The soft tissue, covering the implants, was de-epithelialized using a round diamond bur. U-shaped incisions were made and small flaps over the implants were raised. Small tissue pouches were prepared at the buccal aspects of the implants and the flaps were rotated into it. After removal of the closure screw, a healing abutment with a gingival height of 3.5 mm was inserted.

Provisionalization

Based on the initial diagnostics the dental laboratory finalized the design of the four-unit anterior segment and added distal backings to the FDP for better repositioning. The full contour FDP was then milled in a five-axis milling unit (Zenotec Select Hybrid, Ivoclar Vivadent, Schaan, Liechtenstein) using the classic 98-mm disk in a dry milling environment (Telio CAD A2 Esthetic, Ivoclar Vivadent).

The milled provisional restoration was adjusted and polished and sent to the clinic (Fig 2-7-8).

Two weeks after the abutment connection, and the removal of the healing abutments, healthy peri-implant mucosa was present. At this point directly in the clinic, the laboratory-made provisional was carved out in the palatal parts of the lateral incisors and prepared for a relining based on the now osseointegrated implant. Two temporary abutments (retentive) made from a titanium alloy (TAN) were applied, airborne-particle abraded, and bonded before the open spaces were filled with a classic acrylic poly(methyl methacrylate) (PMMA) material (New Outline, Anaxdent, Stuttgart, Germany) that was later on easy to reline in the yet under-contoured submucosal part. The provisional was fabricated with a kind of ridge flap design to avoid too much pressure on the soft tissue during insertion.

Once the relining material had set, the entire now implant borne provisional could be removed and separated from support backings using a fine diamond disk. The provisional FDP was inserted and tightened.

During the following weeks, the provisional was modified two times with composite resin to optimize the emergence profile (Fig 2-7-9).

Fabrication of the all-ceramic FDP on titanium-base

The patient adapted well to the provisional and felt very comfortable with the occlusion and length of the central incisors.

After a 4-month period the final impression was performed and sent to the dental laboratory to fabricate a zirconia-based restoration. At this point, all the laboratory technician had to do was to copy the initial files created for the initial diagnostics and the provisional and adjust the parameters to the chosen restorative material (Lava Plus, 3M) in the design software (Dental Designer 18, 3Shape, Copenhagen, Denmark), and additionally incorporate a buccal cutback of about 1.0 mm. Besides the rather aggressive buccal cutback, it was also important to pay meticulous attention to maintaining the zirconia frame in the approximate areas and all the way to the incised edge, to protect the weak veneering ceramic and prevent chipping (Fig 2-7-10).

The FDP was milled in a five-axis milling unit (Zenotec Select Hybrid, Ivoclar Vivadent) using the classic 98-mm zirconia disk in a dry milling environment (Lava Plus, 3M). The milled restoration was adjusted in the white stage and infiltrated before it was sintered to its final density. The infiltration was key to transforming the white monochromatic zirconia into an individualized tooth-colored restoration.

Thereafter the FDP was buccally veneered (IPS e.max Ceram, Ivoclar Vivadent) and superficially characterized applying stains and glaze (Ivocolor, Ivoclar Vivadent) according to the custom shade developed with the patient.

Once the zirconia FDP was finalized, it was cleaned with alcohol and rinsed with water. The titanium-bases on the other end were airborne-particle abraded with 2 bar and 50-µm aluminum oxide followed by the application of a silane-containing primer on both the titanium-bases and the FDP (Monobond Plus, Ivoclar Vivadent). Thereafter the FDP was cemented (Multilink Hybrid Abutment HO-0, Ivoclar Vivadent) and carefully polished (Fig 2-7-11).

Integration of the screw-retained implant restoration

The provisional FDP was removed and the implant and adjacent tissues were disinfected with a chlorhexidine solution. After disinfection (Tiutol dent, B. Braun Melsungen, Melsungen, Germany) and the application of a chlorhexidine gel to the submucosal Part (PlakOut Gel, KerrHawe, Bioggio, Switzerland), the screw-retained implant FDP was preliminarily retained to the implants for a period of 2 weeks, by tightening the screws by hand (approx. 20 Ncm) and by closing the screw access holes with PTFE tape and a provisional resin (Telio, Ivoclar Vivadent).

After 2 weeks the abutment/FDP screws were retightened with the final torque as recommended by the manufacturer (35 Ncm). For the final closure of the screw access, the screws were densely covered with PTFE tape. Subsequently, a bonding agent was applied (Heliobond, Ivoclar Vivadent), and the closure of the screw access holes was finalized with a light-curing composite filling material (Tetric Classic, Ivoclar Vivadent). After the light curing, the occlusion was checked followed by polishing of the composite fillings.

The patient was very happy with the efficient and predictable treatment outcome, but also very impressed by the application of the new technologies (Fig 2-7-12).

(Dental Practitioner: Prof Dr D Thoma; Technician: MDT V Fehmer.)

2.7.2 Implant-supported three-unit fixed dental prosthesis (FDP)

■ Posterior regions, titanium-resin base, and restoration (semi translucent multicolor zirconia)

■ Three-unit posterior implant FDP-guided surgery and full digital workflow

The following describes a case involving a regular diameter implant (tissue level 4.8 mm) with titanium-resin base abutments for FDP, semi-translucent multicolor zirconia, and a full digital workflow.

Assessment and treatment planning

A 77-year-old female patient presented herself at the clinic seeking for a replacement of her failing four-unit FDP in the first quadrant. The patient was healthy, a non-smoker, and did not take any medication. The porcelain-fused-to-metal FDP was removed together with the two abutment teeth. The abutment teeth were extracted firstly because of the epigingival fracture of the premolar which was endodontically treated more than 10 years previously, and secondly due to pronounced loss of attachment at the second molar, involving the furcation combined with a periapical radiolucency indicating a perio-endo problem.

Due to the position in the arch and the size of the restoration, it was planned to place two tissue-level implants (Tissue Level, Straumann, Basel, Switzerland) with a regular diameter of 4.8 mm, applying guided surgery and including guided bone regeneration if needed.

After successful osseointegration, the implants were restored with a semi translucent zirconia FDP (Lava Plus, 3M, Seefeld, Germany) on a titanium-resin base (VarioBase for crowns, Straumann).

To increase efficiency it was planned to acquire an optical impression and follow the complete digital workflow from diagnostics to the final CAD/CAM fabricated restoration (Fig 2-7-13).

Extraction

As the FDP lost its mesial retention due to the horizontal fracture of tooth 14, the remaining four-unit FDP was only retained by the second molar 17. Which led to a high mobility grade 3 and its immediate extraction on trying to remove the FDP.

After both teeth were extracted, granulation tissue had to be removed and finally the socket was curetted and rinsed with neomycin solution (Fig 2-7-14).

Implant placement and regeneration

After complete diagnostics and treatment plan, a successful hygienic phase (including non-surgical periodontal treatment) was completed.

With the aid of a guided surgery planning software (SMOP, Swissmeda, Zurich, Switzerland) two implants (Tissue Level SP RN, Straumann) were planned in positions of the first premolar and the first molar in the first quadrant, according to the prosthetic correct position based on the diagnostic wax-up. A surgical stent was produced by means of 3D printing and the implant surgery was performed accordingly (Fig 2-7-15).

A simultaneous guided bone regeneration (GBR) was conducted with deproteinized bovine bone mineral (Bio-Oss, Geistlich Pharma, Wolhusen, Switzerland) and collagen membrane (Bio-Gide, Geistlich Pharma) followed by submucosal healing (Fig 2-7-16).

Abutment connection

The healing period was uneventful and 3 months after the implant placement the clinical examination revealed healthy tissues. At this time point, the abutment connection was performed under local anesthesia. Additionally, an inlay graft harvested from the maxillary tuberosity region was performed to improve the tissue quantity and quality in the pontic area (Fig 2-7-17).

Optical impression and design of the provisional FDP

Four months after implant placement, an optical impression was performed. The corresponding PEEK scanbodies were inserted (Mono-Scanbodies, Straumann) and a powder-free optical quadrant impression (Trios 3, 3Shape) was acquired (Fig 2-7-18).

Once the optical impression was sent online to the dental laboratory the FDP was digitally designed (Dental Designer 18, 3Shape) in full contour based on the respective ti-base (Vario-Base for FDP, Straumann). Thereafter the design software automatically leads the workflow to the model-builder software (Model-Builder, 3Shape) in which the master model was designed and the digitally selected analogs were placed (Fig 2-7-19).

At the end of this extremely efficient workflow, three .stl files were exported from the software, the maxillary and mandibular model along with the FDP.

The generated model files were placed in a 3D printer (Rapid Shape P30, Straumann) and printed with a beige stone-like tinted light-curing 3D printing resin (SHERA Sand, Lemförde, Germany), and thereafter post-processed and light-cured to their final toughness.

The full contour FDP, however, was milled in a fiveaxis milling unit (Zenotec Select Hybrid, Ivoclar Vivadent, Schaan, Liechtenstein) using the classic 98-mm disk in a dry milling environment (Telio CAD A3 Esthetic, Ivoclar Vivadent). The milled provisional restoration was adjusted and polished.

Once the PMMA FDP was finalized, it was cleaned with alcohol and rinsed with water and primed (SR Connect, Ivoclar Vivadent). The titanium-bases on the other end were airborne-particle abraded with 2 bar and 50-µm aluminum oxide followed by the application of a silane-containing primer (Monobond Plus, Ivoclar Vivadent). Thereafter the FDP was cemented (Multilink Hybrid Abutment HO-0, Ivoclar Vivadent) and the cement gap carefully polished (Fig 2-7-20).

Fabrication of the all-ceramic FDP on titanium-base abutment

The patient adapted well to the provisional and felt very comfortable with the occlusion.

After a 4-month period and without taking an additional impression, the laboratory was asked to fabricate the final monolithic restoration. At this point, all the laboratory technician had to do was to copy the initial files created for the provisional and adjust the parameters to the chosen restorative material (Lava Plus, 3M) in the design software (Dental Designer 18, 3Shape).

The full contour FDP was milled in a five-axis milling unit (Zenotec Select Hybrid, Ivoclar Vivadent) using the classic 98-mm zirconia disk in a dry milling environment (Lava Plus, 3M).

The milled restoration was adjusted in the white stage and infiltrated before it was sintered to its final density. The infiltration is key to transforming the white monochromatic zirconia into an individualized polychromatic tooth-colored restoration. Thereafter, the FDP was superficially characterized with the application of stains and glaze (Ivocolor, Ivoclar Vivadent) according to the custom shade developed with the patient.

Once the zirconia FDP was finalized, it was cleaned with alcohol and rinsed with water. The titanium-bases on the other end were airborne-particle abraded with 2 bar and 50-µm aluminum oxide followed by the application of a silane-containing primer on both the titanium-bases and the FDP (Monobond Plus, Ivoclar Vivadent). Thereafter the FDP was cemented (Multilink Hybrid Abutment HO-0, Ivoclar Vivadent) and carefully polished (Fig 2-7-21).

Integration of the screw-retained implant restoration

The provisional FDP was removed and the implant and adjacent tissues disinfected with a chlorhexidine solution. After disinfection (Tiutol dent, B. Braun Melsungen, Melsungen, Germany) and the application of a chlorhexidine gel to the submucosal Part (PlakOut Gel, KerrHawe, Bioggio, Switzerland), the screw-retained implant FDP was preliminarily retained to the implants for a period of 2 weeks, by tightening the screws by hand (approx. 20 Ncm) and by closing the screw access holes with PTFE tape and a provisional resin (Telio, Ivoclar Vivadent).

Stay updated, free dental videos. Join our Telegram channel

Join