Inside Dentistry
April 2017
Volume 13, Issue 4

CAD/CAM Fabrication of PMMA Provisional Restorations

Brasseler system achieves excellent results

The traditional method of fabricating provisionals with polymers and monomers is tedious and time consuming. Milling machines are rapidly replacing analog techniques for producing provisionals. CAD/CAM-fabricated provisionals offer numerous benefits. However, to achieve optimum results, dental technicians and dentists must employ proper instrumentation and techniques.

Provisional restorations fabricated digitally from polymethyl methacrylate (PMMA) yield a highly accurate and anatomically detailed result. Axial contours and occlusal anatomy generated from tooth libraries produce supplementary anatomy that mimics natural teeth. Utilizing traditional acrylic burs and a wet pumice buff wheel can potentially remove too much surface material, damaging the subtle anatomic detail. 

Brasseler USA has developed a PMMA polishing protocol and specific finishing instruments for CAD/CAM restorations. The system is designed to allow greater control of shaping and polishing while still maintaining the contours and supplemental anatomy created by the digital fabrication process.

Utilizing properly designed and shaped instruments like the H261PSQ.023 PMMA lab cutter, the supporting pins can be sectioned from the PMMA puck at 15,000 RPM without damage to the restorations.

Residual circumferential lines remain on the surface of PMMA materials that have been generated in the CAD/CAM process. The depth and spacing between these lines is directly related to the “step-over” parameters of the milling machine and the tools that are used. The polishing sequence of the PMMA provisional should allow for the removal of these lines without removing the desired anatomy.

To achieve this, Brasseler USA has developed a Feather Lite™ Polisher (PFL26FHP), which is specifically designed to polish PMMA in a more controlled manner than traditional acrylic burs. It is easy to use and adapts to the natural contour of the provisional with minimal effort. Unlike acrylic burs, these polishers do not “catch” the surface of the soft PMMA. Instead, they polish and contour the axial surfaces as well as the occlusal and incisal areas of the restoration without removing the desired anatomy. A light touch at 8,000 RPM to 10,000 RPM is all that is needed to achieve excellent results.

Once the needed refinements to the shape and surface finish are complete, the final surface sheen is achieved with the ET® ProviPro™ System (SWR22M and SWR22F). Con­sisting of a medium and fine polishing compound, these polishers are the perfect complement to achieve a lifelike finish.

This new K0330 PMMA Adjusting & Pol­ishing System, exclusively from Brasseler USA, is perfectly suited for the practitioner looking to achieve the best possible results with CAD/CAM fabrication of PMMA restorations.

•New PMMA cutter configuration cuts efficiently without debris load upNew Feather Lite™ polisher adapts to every surface without damaging anatomy, minimizing polishing time
•ET® ProviPro™ aluminum-oxide impregnated cotton buffs provide superior final polish without pumice
•Complete system includes three PMMA cutters, new Feather Lite™ and ET® ProviPro™ polishers, and a diamond disc

For more information, contact:
Brasseler USA

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