The tooth and gingival morphology were designed in DentalCAD (exocad; Fig. 1). On the basis of this design, a passive bar was designed (Fig. 2), manufactured in aluminium and sent to the clinic for testing and adjustment.
Unlike teeth, which are connected to the bone via the periodontal ligament, implants have a rigid connection to the bone. Therefore, the passive fit of the superstructure is particularly important. A misfit can have negative effects, such as detrimental stress at the bone–titanium junction or prosthetic complications such as screw loosening. After verifying the seating of the aluminium bar, the dentist sectioned and splinted it in the corrected position to achieve a passive fit (Fig. 3) and then sent it back to the laboratory.
At the laboratory, the implant analogues were attached to the corrected bar, and their positions were secured in a gypsum base (GC FUJIROCK EP Premium Line, Polar White) using a silicone base former. The resulting analogue and model assembly was then scanned with scan bodies in place, and the meshes were superimposed in exocad software to locate the corrected positions of the analogues in the 3D space of the original design.
Prototype verification and framework fabrication
Once this position had been confirmed, a prototype based on the digital design and incorporating the optimised implant positions was 3D-printed (Fig. 4). This step allowed verification of gingival pressure, function and aesthetics intra-orally before proceeding to the definitive structures.
After verification of the passive fit and the intra-oral mock-up, the primary and secondary structures were designed using Blenderfordental plug-ins for Blender software. The primary structure consisted of a titanium bar (Fig. 5) that would be screwed on to the prosthetic abutments and then completed with a secondary zirconia structure. A minimum material thickness of 0.8 mm was maintained around the screw access holes. The secondary structure was milled from a 25 mm GC Initial Zirconia Disk Multilayer Elite blank (Shade A2; Fig. 6).
The zirconia structure was then customised. Manual vestibular reduction was carried out in both the white and pink areas using different burs and stones in order to achieve an individualised effect between the teeth (Fig. 7). These manual changes were made while the material was still in its green state, allowing the morphology to be refined before sintering.
Characterisation of the zirconia structure
After sintering (Fig. 8), internal characterisation of the gingiva and teeth was carried out using GC Initial IQ Lustre Pastes ONE, GC Initial Spectrum Stains and GC Initial IQ Lustre Pastes NF Gum Shades (Figs. 9a & b). For the teeth, Lustre Neutral Fluo was used as a fluorescent base, and different colours were then applied on top to create various chromatic areas and effects. The cervical areas of the teeth were coloured using Lustre Body B (L-B). On the canines, this was applied more intensively in order to give them more chroma than the incisors.
In the middle area of the central and lateral incisors, a light-refracting zone between the cervical and incisal areas was created using a mixture of Lustre Value (L-V) and Lustre Enamel Effect 1 (L-1), contributing to a more natural appearance. In the incisal area, a light-absorbing zone was created at the free edge using Lustre Enamel Effect 5 and a mixture of Lustre Enamel Effect 6 and Lustre Enamel Effect 3. The mamelons were created using a mixture of L-V, L-1, Lustre Body B (L-B) and SPS-4.
The gingival characterisation was completed using L-N as a non-fluorescent base, to which different gingival shades were added to create a natural appearance. The free gingiva was coloured using G-23, LP-M4 and G-24, while G-35 was used for the attached gingiva and G-36 for the alveolar mucosa. After firing, the natural colour and gloss were already visible (Fig. 10).
Fig. 8: Zirconia framework after sintering.
Fig. 9a: Application of GC Initial IQ Lustre Pastes ONE, GC Initial Spectrum Stains and GC Initial IQ Lustre Pastes NF Gum Shades during internal characterisation at an earlier stage.
Fig. 9b: Application of GC Initial IQ Lustre Pastes ONE, GC Initial Spectrum Stains and GC Initial IQ Lustre Pastes NF Gum Shades during internal characterisation at more advanced stage.
Fig. 10: Result after firing of GC Initial IQ Lustre Pastes ONE, GC Initial Spectrum Stains and GC Initial IQ Lustre Pastes NF Gum Shades.
Fig. 11: Application of GC Initial Zr-FS for characterisation of the teeth and gingiva.
Final layering and clinical result
Further characterisation was then carried out using GC Initial Zr-FS. Masses of this feldspar-based zirconia veneering ceramic added depth and vitality to the structure. Enamel Opal EOP-2 and EOP-3 and Enamel E-58 were used to mimic enamel, while Cervical Translucent CT-22, Fluo Dentin FD-92, Dentin D-A2 and Clear Fluorescence CL-F were used for the teeth. Gum GM-24, GM-34 and GM-36 were combined with Gum Universal to complete the gingiva (Fig. 11).
The result was a high-end prosthesis composed of a high-precision titanium bar and a zirconia secondary structure, an approach that stands out as a premium option for full-arch rehabilitation (Figs. 12a & b). The blue effect at the incisal edges was the result of the combination of the internal characterisation and the application of EOP-3 in the same zone, creating a 3D effect (Fig. 13). Its smooth, polished surface would facilitate maintenance and support optimal hygiene. The prosthesis was seated in the mouth and evaluated clinically, showing a stable intra-oral result (Fig. 14) and a harmonious final appearance (Figs. 15a & b).
Material properties and workflow benefits
GC Initial offers a complete system for achieving high-quality prostheses efficiently. Its most notable benefits are the following:
- Stability: The GC Initial materials perform reliably and predictably. When combined with a sound protocol, they give dental technicians excellent control throughout the workflow.
- Reproducibility: Used within consistent protocols, these materials support reliable, repeatable outcomes and help minimise the risk of error.
- Time: Customisable workflows allow adaptation according to the needs of each case, enabling greater efficiency and productivity.
- Aesthetics: With the appropriate protocol, vibrant shades and consistency of results, a highly aesthetic and natural-looking outcome can be achieved case after case.
Taken together, these advantages make GC Initial an excellent option for delivering durable and aesthetic prostheses. By prioritising quality and precision, dental technicians can help ensure a lasting positive impact on both patients and clinicians.
