Written by George Freedman, DDS Wednesday, 14 August 2013 08:49
In First Impressions George Freedman, DDS, gives readers a brief summary of products that have recently been introduced to dentistry, based on his clinical experience.
Sof-Lex Spiral Finishing and Polishing Wheels
Polishing is a relatively simple and straightforward process in dentistry. It involves the progressive application of a series of abrasive materials to the surface that is to be polished. Typically, each abrasive material has a finer grit than the previous one, eliminating the striations left on surface. Eventually, a smooth and glossy surface is achieved that feels enamel-like to both the instruments and the tongue. This even, undetectable topography is expected at the tooth-restorative interfaces as well. Many polishing systems can achieve an acceptable result. The problem with most is that they are too time-consuming and almost invite the skipping of steps and inferior surface result. Given the average chairside billing rate of $350/hour (or $6 per minute), even a 5-minute polishing procedure can eat into productivity significantly. The restoration must be polished and polished well but how to do this efficiently and effectively? 3M ESPE has introduced Sof-Lex Spiral Finishing and Polishing Wheels, innovative and uniquely flexible spiral wheels that adapt to both regular and irregular and convex and concave dental surfaces from any angle. The system is efficient: 2 steps are all that are required to polish restorations to a high-gloss finish. The Sof-Lex Spiral Finishing and Polishing Wheels can be used for both anterior and posterior restorations, eliminating time-consuming bur changes. Abrasive particles are embedded into every part of the wheel, and thus every surface can be used to polish. The system consists of 2 wheels. The fine (beige) finishing wheel eliminates the surface scratches developed during shaping and contouring. The superfine (white) polishing wheel imparts the high-gloss polish that discourages plaque formation and contributes to aesthetics. Sof-Lex Spiral Finishing and Polishing Wheels are effective, easy, and fast.
|The cementation of crowns used to be a simple procedure. Mix the zinc phosphate, place it in the crown, insert over the preparation, wait for the set, and clean the margin. The available cements were not adhesive, but then again, neither were the crowns (gold, acrylic, ceramic, and nonprecious). The tooth interface, whether on enamel or dentin, was left to fend for itself. Many of the early cements were highly acidic, sensitizing vital tooth structures for ex-tended periods. The introduction of ad-hesive resin cements represented a para-digm shift in indirect restorative dentistry. These cements adhered micromechanically (to a greater or lesser degree) to tooth structures, greatly improving crown retention and even more importantly, eliminating post-cementation sensitivity. The cements could also be made to adhere to restorative materials, including silane-treated feldspathic ceramics and certain semi- and nonprecious metals. Thus, a tooth-cement-crown monobloc was formed, mimicking the dental-enamel integration of the natural tooth. The introduction of zirconia and alumina ceramics were a mixed blessing; while they were clearly superior in wear, fracture resistance, and strength to earlier ceramic materials, they could not be bonded to natural tooth structure with adhesive resin cements. Dentists were reluctant to give up the benefits of bonding. Danville Materials has introduced Z-Bond, a single-component zirconia and alumina primer that develops an adhesive interface between nonreactive ceramics and resin and is indicated for cementing and repairing indirect restorations. It also improves adhesion to precious and nonprecious metals. Simply apply Z-Bond to the internal aspect of a zirconia or alumina crown, bridge, inlay, or onlay and confidently cement with an adhesive resin. |
For more information, call (800) 827-7940 or visit the Web site located at danvillematerials.com.