ALL ON 4 Workflow. By Matteo Neroni

ALL ON 4

WORKFLOW

By Matteo Neroni

After several years of research and development in the type of total prosthetic rehabilitation on implants, it has been established that one rehabilitation done on 4 or more implants is amongst the safest and long-lasting rehabilitations existing on the market today.

The fundamental basis of this rehabilitative procedure is planning by means of photographs and RX

In this first step, an AO4 example of the Mascellar Superior, the dentist alongside his/her dental technician will evaluate the possibility of a bone reduction.

This type of evaluation is done by overlaying multiple images of the patient with a frontal photograph of the rx, with which one is able to plan where the new transient line can be found in an extremely accurate way after bone reduction, always being when the patient smiles showing the gum in an excessive way. (Fig.1)

At this point, facial planning begins. (Fig.2)

After the planned bone reduction, the patient's new smile is virtually designed, respecting the golden proportions, the correct curves, and masticatory functions (fig.3)

After surgery and correct planning, both aesthetic and functional, this is an example of the post-operative AO4 where the perfect symmetry and accuracy is shown, in the position of the implants, which the clinician is able to do with this type of planning; in this specific case in FreeHand (fig.4)

This type of planning, as I said, succeeds in satisfying the functionality in relation to aesthetics by deciding the inclination of the implants and the exit of the screw channel, always a local tongue, so as to not compromise the harmony of the reconstruction.

This is the typical technique of immediate loading by conversion of a total prosthesis, inside which a bar welded to TMC1 will be inserted.

After a period of 3 to 6 months necessary for osseointegration of the implants, the patient returns to the clinic to scan the prototype that had been worn during the healing period. New photographs are taken with the prototype in place, as well as 3D facial scans. (fig.5)

This step is extremely vital and fundamental for the laboratory for the success of the case.

The 3D facial scan reveals the exact inclination of the Maxilla and how much lip support our patient has. Facilitating the positioning of the new arch in the virtual space.

In the meantime my laboratory will prepare a confirmation Gig, to make sure that the implants are firmly in the starting position.

At this point, when you have all the information necessary to proceed to the next step.

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CAD STAGE Once you have entered all the data in the CAD, you go back to work on the golden proportions modifying the blue areas in the 3D scan of the starting prototype (fig.6)

I am going to insert my virtual teeth into the CAD space using libraries, which will follow all the lines I have traced, respecting the proportions and symmetries. In this step I am able to variously increase or decrease my lip support. (Fig .7)

Once the 3D planning of my reconstruction is complete and after a quick check by the clinician, milling or 3D printing of a further resin prototype is performed. This is necessary for the clinician to adjust or balance occlusion and group function, for the patient to approve the aesthetic line or if he/she has any particular requests to make to the prototype, and for the technician to proceed with the milling of the definitive reconstruction of the arched zirconia arch.

GREEN STAGE I personally think that the green stage is of vital importance.

I call it "The Key", in this step the true artistic vein that lies behind the digital figure of modern dental technology emerges.

This step enhances the craftsmanship of this craft that comes from the old school, through the sculpting of Zirconia by obtaining detailed surfaces with regards to textures and separations, giving life to our zirconia block. (Figure 8)

The care of the gingival surface and the harmonic exit of the tooth from it are of vital importance, giving a three-dimensional effect to our block, which aims to keep and imitate the natural aspect in every little detail.

After the sculpting phase there is the colouring of the zirconia, using colours that imbue the surface, thus creating a play of light, shadows and shades. This is to better customize our reconstruction, making it extremely true to what the patient originally had. (fig.9) (fig.10)

Personally, as a dental technician, I pay a lot of attention to the details in this specific step. For me every Toronto that I sculpt and colour is as if one creates a small work of art every time that is one-of-a-kind, unrepeatable, unparalleled, and alive!

Striving to fully satisfy the aesthetic need of the patient that I find myself in front of and carefully selecting the type and shape of my arch, which will fill and soften the visual context of the patient.

FINALIZATION In this step, the only part on which I apply porcelain is on the gum. The latter gives vitality and naturalness to my rehabilitation, and with a special colour guide, most of the times I can mask the transition line between fabric and Toronto.

The surface of the teeth is treated with Basic glaze only, since with the colouring in the Green-stage where I can achieve a natural effect it seems useless to intensify something that is already natural in itself. (fig.11)

In my opinion, the optimal success of a Toronto on an aesthetic level, is precisely finding the right balance between the two distinct parts of the gum and teeth, treating them as two distinct and separate identities.

But with the correct relationship between them, they make my every Toronto unique, as unique as the patient who will wear it to smile.