Polishing lifelike composite
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The aim of this step-by-step article is to show how easy is to obtain extremely shiny composite restorations, with rich morphology and long lasting surface stability changing just very few times the rotating instruments in our contrangle.
This article is part of chapter 10 of the book “Layers” by Jordi Manauta and Anna Salat published by Quintessence books on September 2012
Fig1.- The frst rotating instrument that we will use is the 4th bur of the Finishing Style Kit (831-204-012 Komet, Germany) this is the most important instrument for this simple but advanced polishing protocol.
Fig 2.- A sample tooth of white composite, obtaining on purpose a bad surface after final polymerization. Note that the gloss is not real, corresponds only to the surface raw composite. The color white is to obtain full visibility in this exercise.
Fig 3.- Probably the most important step is the first of them. We place in the contrangle @2000rpm (maximum) the diamond bur and obtain a smooth surface, trying to eliminate all the excesses and irregularities to obtain a continuous surface. The aim is to educate ourselves to achieve a “biscuit try” like surface which any ceramist can teach us very precisely. This step usually is where we focus most of the time in the finishing and polishing stage.
Fig 4.- with a sharp pencil we mark the proximal angles to define the shape of the tooth (primary anatomy)
Fig 5.- Following the marked lines, always with the same bur, we do some pre-interproximal grinding at low speed. Proximal grindig will be done with the following rules, outside the lines with discs and strips, inside the lines with diamond bur. This step can be done clinically and often we must get help with red finishing strips. Note how the tooth changes its shape dramatically.
Fig 6.- With the pencil we can mark the path to do some incisal characterizations (if needed) in this case we make the proximal lobes more short as in many young teeth.
Fig 7.- after incisal grinding (with the same bur or disc) we mark some incisal lobes division and develop them with the tip of the bur. If they need to be really sharp we can help ourselves with the red diamond strip.
Fig 8.- In order to develop secondary anatomy (macro texture), we mark some vestibular waves which must be sharper in the cervical and wider in the incisal, but always very smooth, we shall never see the “bur shape” marked on our restorations. To achieve this we must pass the first bur of the Finishing Style Kit following the shape of the lines to mark the depth.
Fig 9.- Low speed multi blade round bur to develop the secondary anatomy.
Fig 10.- After marking the depth, we need to smooth the grooves by returning to the diamond bur with ovements from mesial to distal, applying more pressure when approaching the center of the groove and releasing int he surroundings to make a nice rounded groove and not a canal.
Fig 11.- With a pencil we mark the tertiary anatomy (micro texture), note that the more close and parallel the grooves are, the more natural they look.
Fig 12.- With the tip of the bur, we mark one by one and very carefully each sulcus.
Fig 13.- We can use a rubber cup to smooth the micro grooves, Opti-1-Step (Kerr, USA)
Fig 14.- Aspect of the micro grooves after smoothening with the rubber cup. These cups mostly polish, but if we apply stronger pressure the lines can slightly dissapear to our convenience.
Fig 15.- After the finishing stage with the bur (which we consider to be the most important) and optimising it with the rubber cup, we start the polishing and shinnig, to do this we switch to the goat brush cup and apply a super charged diamond paste (Diamond Twist SCL, Premiere USA), we spread the paste with the brush without rotation, then we start @3,000 rpm with no water, doing really slight touches otherwise extreme heating can happen and ruin the composite surface, and then @15,000 rpm with water in order to give extra sine and wash away the paste.
Fig 16.- Diamond Twist SCL, a dense and extremely effective one step polishing paste (Premiere, USA)
Fig 17.- Natural bristles goat brush (Kerr, USA), note that this is not a prophylaxis Nylon brush
Fig 18.- For the extreme high gloss polishing, we switch to the felt wheel with water and 15,000 rpm (or more) to avoid overheating.
Fig 19.- Felt wheel, there are plenty alternatives on the market, the only detail we have to take care about is not to have pre-impregnated wheels, as they can ruin our previous shine isntead of enhancing it.
Fig 20.- The restoration showing a “ceramic like” appearance, after cleaning with a gauze the paste excess.
Fig 21.- When working extraorally we can use some silver powder to study shape, texture and every minimum detail of our work. Avoid doing this in the mouth, especially whitout rubber dam.
Fig 22.- The threedimensionality of the texture when twisting the tooth 45 degrees.
ConclusionsIs easy, with the use of a limited number of instruments, to obtain lifelike composite restorations, almost every step of the protocol is identical to the step-by-step of the technicians finishing the ceramics. Modern composite materials, especially those containing nano fillers have an excellent polishing and polishing persistence in time. We consider this (together with perfect bonding strategy) to be the most important factor to the longevity of our restorations.
No high speed turbine was used at any time.
Other full protocols on how to obtain different surfaces and textures are described in the book Layers, powered by Styleitaliano (Quintessence 2012) by Jordi Manauta and Anna Salat