Indirect composite restorations in posterior teeth give us advantages to enhance the quality, durability and supreme aesthetics. An Article by… Jordi Manauta Submited: 23/04/2012 On late 90′s and early in 2000′s there was a frenetic trend on replacing amalgams for “aesthetic” restorations. Now, a decade after we are experiencing how these materials are failing because of wrong techniques.
The patient came with two old ceramic inlays which presented marginal leakage, aesthetic failure (probably since day 1) and fractures that compromises the tooth integrity.
After field isolation with rubber dam, a wedge was inserted interproximally, one of the most important steps during cavity preparation. The wedge separates teeth, compresses the papilla and pushed the rubber dam apically to the margin.
Ceramic inlays were removed with diamond burs and generous water. Note how the cavity base is still mixed with composite cement excess which was not perfectly bonded to the old ceramic restoration.
The cavity base was removed with rounded low speed carbide burs and water. Note how some areas were missed. When the water wets some materials they blend into the structure and become invisible.
For the final stage of the caries removal, a caries detector was applied for 10 seconds and washed. With low speed carbide bur and no water the remaining caries and old base were removed. Note how the wedge is slightly touched and the rubber dam is interfering in the margin area.
Walls that meassure less than 2mm were removed. At his stage a 5% clorhexidine acquous solution is placed in the sound dentin for 5 minutes. A sectional matrix is carefully placed to ensure a complete visibility of the margin, at the same time clorhexidine keeps working.
After matrix removal, the preparation was finished and polished. Then the rubber dam was removed and an impression was performed.
One week later the case is ready to be cemented. The isolation was performed and the composite base was sandblasted with 50 microns Aluminum oxide sand. After sand blasting chlorhexidine 5% solution was placed for 5 minutes.
The restorations are double checked with the rubber dam to be sure that no inteferences due to the isolation are found.
This image is intended to highlight the importance of composite conditioning. Sand balsting is the most effectuve surface treatment for bonding to polymerized composite surfaces. After the second trial, the restorations are sand blasted and thoroughly cleaned with alcohol to eliminate sand traces.
Selective enamel etching was done for 15 seconds. Dentin was etched with an especial self etching primer. And composite base is already treated with the sand micro retentions.
The same bongind procedures are carried out at the same time in the restorations. Primer is applied to the restorations and to the tooth for one minute and then completely removed with air. Several studies support this action possitively due to the dramatic increase of wettability.
Bonding is placed in the restoration and in the tooth. Then thinned carefully with air, and polymerized for a full minute. If the bonding agent is dense, it is NOT advisable to polymerise.
The cement is placed in the restoration. A hybrid semi-translucent composite is placed with the modeling spatula over the whole surface. After this is done, the restoration is heated to 50 in a composite heater, always in dark conditions.
The restoration is carried to the cavity and firmly pushed with the big rounded plugger condensa, excesses will start to come out slowly but constantly.
The big excesses are removed immediately with the instrument fissura.
Interproximal excess is easily removed due to the smart localization of the margins.
A common mistake is to polymerize at this stage. When applying pressure again, composite excess flows again.
After 30 seconds of pressure excess comes out again. When excess is small we can remove with a brush.
The final excess are removed and the restorations is ready for polymerization. Important note: Cementation must be done with low light conditions
Initial polymerization is done under mild pressure with the instrument.
Polymerization is carried out under glycerin to polymerize perfectly the oxygen inhibited layer. High power light is applied for 5 minutes.
With a rubber abrasive point, the big excess is trimed. With a goat-hair brush and polishing paste the final gloss is achieved.
The restorations after polishing show a high-gloss look.
Once removed the rubber dam, occlusion check-up os performed. With a multi blade bur, these interferences are removed. Normally with these kind of burs surface gloss is not damaged.
Composite selection is done NOT to make the therapy more economic, but because of their REPARABILITY, which makes these type of restoration one of the most convenient choices.