Giuseppe Marchetti: Indirect Posterior Recipes
Indirect restorations are a system to achieve goals that often with direct ones are much more difficult to reach. In literature is quite universally recognized that we can do indirect posterior restorations when we have the presence of large and numerous cavities affecting two or more walls (to avoid placing numerous matrices), when we need to cover multiple cusps (to achieve better anatomy) and when there’s a lack of enamel in the cervical area or it is totally absent (to maximize precision and minimize contraction of the material). So now let’s see how we can reach these goals in a simple and predictable way.
Preoperative aspect. Old fillings that need to be removed and new and secondary decay to be cleaned.
We can see vestibular decay as well in 2.6 & 2.7
After a right isolation (perfectly invaginated and non filtrating), using the rubber dam is the only reliable and repeatable way to achieve predictable results in adhesive dentistry.
The old fillings are removed. We can see secondary decay and new lesions as well.
After the removal of the decayed tissues with a low speed carbide bur we did simple preps, removing weak tissue, covering the weakened cusps, cleaning the dentines surface with glycine powder and leaving the undercuts that later on will be filled whit a build up composite.
Using an etch and dry two step technique (see my blogs first entry for the self etch description), with a selective etching of the enamel with phosphoric acid (37%), then we proceed to hybridized the dentine.
Then with a flow we have done the build-up in the three teeth to create an immediate dentine sealing, to avoid an excessive thickness of the indirect restorations and to achieve a convenience shape of the cavities (expulsive).
After the removal of the dam we took the impressions
Impressions with a polyether, in one step with two viscosities
A wax up of the indirect restorations was done by the laboratory in order to create the right anatomies and shapes, copying those features into the composite restorations.
Then the laboratory did the restorations using just one dentine (A3 shade) and one enamel (A1) shade and brown stains mixed with gold in order to create natural sulci.
The next step was to try the restorations, to check the right fit, just before doing the rubber dam isolation for the cementation stage. At this stage we dont have to check the occlusion, that will be checked after the cementation.
This is the main tip of this article: Standardizing a color recipe for direct and indirect can be an enormous advantage, if the technician know very well his material, the clinician shall know it and do the color matching with the same, otherwise theres a risk of getting it wrong. In this case both the dentin and the enamel of this particular system are rather translucent and using darker colors could mean the chromatic failure of the case, as with a very dark or gray tooth.
Blue photodam , wich the autor is beta tester for the brand, was used for cementation.
New filed isolation was performed. The author has the habit to isolate with different colors form the preparation appointment and for the cementation appointment, to have more differentiated images.
The restorations were tried again to check the marginal and the contact areas. Under the rubberdam they might seem more stretch, and thus special care must be taken. Special attention must be placed in the order of the restorations, in case the rubberdam alters the initial fit.
Then the restorations were cemented one by one, using some teflon (PTFE) tape to avoid contamination of the surrounding cavities and bonding between restorations.
An etch and rinse two step technique was done (see Clinic Meets research Vol 1) etching the enamel again for 30 seconds.
Applying just the bonding over the enamel and the build up, because no dentine was exposed the primer wasnt needed again. In case of doubt we have to use the primer too.
The bonding was polymerized and then with a heated composite (55°) the onlay was luted. Generally composites in a carpule presentation contain a softer composite with the ideal properties for cementation with normal heated composite.
We removed the uncured excess with the Fissura Intrument (LM Arte by Style Italiano) and then we polymerized the onlay for 180 seconds for each surface.
Then we did the next cementation and so on.
At the end a quick finishing and polishing was done under the dam
Just after the removal of the dam we could see the right shapes of the restorations
The occlusal view at the end of the session and after the occlusal control. Little shape corrections were needed expecially in 2.7 mesial surface.
After one week we saw a good integration and a good new morphology.
The occlusal view completely satisfied our expectations.
Before and after. The author wishes to thank Sebastiano Nardo (Dental Design Parma -Italy) for the lab work.
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