Recipe for Class IV Restorations

Class IV restorations are probably the biggest aesthetic challenge especially for how difficult it is to hide the margin. The Styleitaliano philosophy was based established on the CBT technique (Controlled Body Thickness) where everything from the color matching stage to the build-up and needed corrections are strictly calibrated with the rule of 0,5mm of enamel. A winning strategy in most cases.

This strategy is extremely efficient when planning the case with the help of a personalized shade guide (My Shade Guide, Smile Line). Knowing that building a personalized shade guide unfortunately is not feasible for many colleagues, some companies decided to make the official “Styleitaliano” recipes, in order to be able to make the color match stage with the VITA Classical shade guide and use the proposed color combination.

As an example, in this case the material used was Filtek Supreme XTE (3M ESPE)… which was performed following these recipes

WD + A2E = A0
A1D + A3E = A1
A2D + A3E = A2
A3D + A3E = A3
A4D + A3E = A3,5
A4D + A4B = A4

The enamel shade is always 0.5mm

style italiano styleitaliano dentistry

Fig.1
The initial case shows a young patient coming with an emergency to the office one hour after breaking his central incisor. He was suffering no particular pain but a little sensitivity when applying air or cold water due to the dentinal exposure. No pulp complication was found.

style italiano styleitaliano dentistry

Fig.2
Immediately the color is taken, while teeth are still completely hydrated, and the tab which matches the most was A2 from the VITA classical shade guide. We know at this exact moment what are the colors to build two layers and have a final A2 shade.

style italiano styleitaliano dentistry

Fig.3
Close-up of the color matching stage. At his stage, the dentin is sealed with adhesive, polymerized and the patient recalled after a couple of days in order to have a one hour appointment with a wax-up from the laboratory.

style italiano styleitaliano dentistry

Fig.4
On the second appointment, the patient will be anesthetized and the teeth isolated. A silicone index was taken from the plaster model and now we will use it to build the palatal enamel layer.

style italiano styleitaliano dentistry

Fig.5
In this case we selected a chamfer-like finishing line, prepared with a No.1 fine grit diamond bur, in order to be able to blend the composite in a small margin which is resistant. Authors frequently suggest this kind of margin and the medium bevel.

style italiano styleitaliano dentistry

Fig.6
Selective enamel etching was done, slightly over-etching the vestibular enamel.

style italiano styleitaliano dentistry

Fig.7
Rinsing of the acid etchant, generously, with water for 20 seconds.

style italiano styleitaliano dentistry

Fig.8
Application of a multi-mode generation universal bonding agent (Scocthbond Universal, 3M ESPE). This agent must be rubbed for 20 seconds, author suggests to let it act for at least an extra 20-40 seconds and then carefully thin with air before curing.

style italiano styleitaliano dentistry

Fig.9
Polymerization is done for one minute with a high power lamp (Elipar deep cure), to obtain a good conversion of the adhesive, making this way the highest quality hybrid layer. In order to do this successfully, high power lamps deliver much energy and thus much heat, to polymerize for one minute may be a cancer for many clinicians, the suggestion is to blow air during this minute.

style italiano styleitaliano dentistry

Fig.10
A mark is done between the palatal surface angle and the silicone index, in order to limit the area where we are going to place the palatal enamel.

style italiano styleitaliano dentistry

Fig.11
With this line we can know exactly where the palatal enamel will be located, avoiding to do it intraorally and gaining much precision while constructing this layer outside the mouth..

style italiano styleitaliano dentistry

Fig.12
Enamel is placed without crossing the line. Of course the smoothening of the composite can be done now or inside the mouth, depending on how convenient or conformable is for the clinician.

style italiano styleitaliano dentistry

Fig.13
Once the palatal layer was placed, smoothened and polymerized, we can remove the silicone index, from now on it won’t be helpful anymore.

style italiano styleitaliano dentistry

Fig.14
Building up the proximal walls
– The distal with the help of a posterior matrix
– The mesial free hand due to the presence of a diastema
Once the stratification “box” is polymerized, is time to place the dentin.
Then the dentin A2 was placed and calibrated with this special instrument LM Arte Misura (LM instruments, Finland). This step is of utmost importance. It gives us the exact space needed for our enamel. Which corresponds to the 0,5 mm we have in our personalized shade guide (if used) and that corresponds to the recipe created by Styleitaliano for Filtek Supreme XTE (3M-ESPE).

style italiano styleitaliano dentistry

Fig.15
As an optional step, we can copy the mamelons features and calibrate again.

style italiano styleitaliano dentistry

Fig.16
After polymerizing the dentin, some opaque white characterizations are inserted. Using the WD (White Dentin) some spots were created above the dentinal core and a roll was placed in the incised edge in order to imitate the incisal halo.

style italiano styleitaliano dentistry

Fig.17
Enamel A3 is placed and smoothed with the LM Arte Modella instrument (LM instruments, Finland) and brushes. Final Polymerization can be done.

style italiano styleitaliano dentistry

Fig.18
Final polymerization should have the same characteristics as the polymerization of the Bonding. We can opt to place some oxygen blocking agent as Glycerin or similar and polymerize.

style italiano styleitaliano dentistry

Fig.19
Initial contouring (primary anatomy) is done with discs. While we copy the morphological characteristics of the neighbor tooth with a pencil to reproduce them immediately afterwards. With a low-speed diamond bur we will smooth all the composite surface before starting the reproduction of the morphology features.

style italiano styleitaliano dentistry

Fig.20
We place the pencil marks mirroring the contralateral tooth and with the same bur for the primary finishing we can reproduce the secondary and tertiary texture.

style italiano styleitaliano dentistry

Fig.21
The secondary texture must be thoroughly worked, the risk of having two ugly bur marks is high, the bur must work from side to side in order to smooth and have this wave appearance. This stage takes the most time, it needs the most precision and thus our best attention.

style italiano styleitaliano dentistry

Fig.22
For the fine finishing we will use a Sof-lex spiral disc for one minute making touch and go movements with an up-low direction.

style italiano styleitaliano dentistry

Fig.23
For the polishing and gloss we will use the white Sof-lex spiral disc, it is optional for the clinician to use them in combination with a paste or dry. In case of using them dry, a final felt can help very much for an extremely high gloss.

style italiano styleitaliano dentistry

Fig.24
The case immediately after rubber dam removal, we must not worry about the color difference, this will be evaluated after the rehydration of the teeth.

style italiano styleitaliano dentistry

Fig.25
Control stage, after one month the teeth were rehydrated and now the composite is well integrated.

Conclusions

The CBT technique, combined with thorough knowledge of your shades and of the critical steps of class IV restorations, make it easy to get a natural, aesthetic and functional outcome.

Bibliography

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