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News Bulletin : ADA News Bulletin June 2011
53 JUNE 20 11 TEASER This TEASER is a dental device, used in both the surgery and the laboratory. It was provided by Hugh McConville, who is still working as a dentist at age 77, and long may he do so. A handsome, inscribed, pewter ADA paperweight will be awarded to the person who identifies the item. If more than one correct answer is received, all names will go in a hat and a winner will be drawn out by Margaret. For every clinical hint accompanying your answer, an extra slip goes in the hat. If your name is the one engraved on the item, we will give it to you. If you appear in the CH column as a contributor or hinter, you may find that your colleagues buy you drinks at your next study group meeting. Send some in to find out to: Barrie Gillings, Phone: 02 9144 3787; Fax: 02 9440 9159; e-mail: firstname.lastname@example.org You might be surprised at how many of your friends will notice that you have been recorded as a clinical hinter. Send in a hint, and if they comment, ask them which hint they liked best, and claim it for your own. To avoid possible embarrassment, any incorrect TEASER answers printed will, from now on, be anonymous. The dramatis personae for this month are: R Darcy, G Howe, I Martin, M Knapp, E Reballato (ANZAE), M Reznik and N Rock. The FDA and the US National Institutes of Health are researching the area, and it is possible that the use of BisGMA in food containers may be banned. The reason we mention it here is that some patients may find out that BisGMA is used in some of our dental restorative materials, and wayward press reports, such as: 'poison in dental fillings' may appear. The good news is that the amount of BisGMA escaping from a dental restoration is minute and temporary, and our own Therapeutic Goods Administration can be relied upon to monitor the safety of filling materials. MELTING ICE We all know that ice melts at temperatures above 0°C. But it is hard to tell whether sheets of ice in the arctic are melting by looking at the surface. Melting underneath can be undetectable, whether the sheets are on land or in the water. The Australian Geographic (Jan-Mar 2010, pp62-71) reports on a survey of Greenland's Petermann Glacier ice thickness. Investigators in three kayaks fitted with sonar traversed the river of melted water on the glacier surface for about 20 kilometres to determine whether the glacier was on bedrock or floating. In the latter case, the terminal 120 square kilometres of the glacier, already showing signs of cracking, could detach and float into the Kennedy Channel of the fjord. This would have the most undesirable effect of increasing dramatically the rate of flow of the remaining part of the glacier, and facilitate the melting of the Greenland ice sheet. They found that the terminal part of the glacier is floating, and may break off, and the base of the glacier is melting at a rate 25 times that of the surface. Flows of warmer water are having an important impact on floating glacial tongues and ice sheets. CLINICAL HINTS The following hints are not endorsed by the ADA or your Compiler. Dentists submit them because they have found them helpful, but it is your decision to use them or not. Object to a hint? Don't write a letter of complaint; simply send in a better one. You can be anonymous or use a pseudonym and no one will know which hint is yours. Securing a rubber dam with dental floss on mandibular incisors is effective, and often the only way, if the tooth shape does not allow the use of a rubber dam clamp. But when a radiograph is taken, there is no metallic indicator that rubber dam was being used. For dento-legal reasons, be sure to note on the treatment record that dam was used. Alternatively, temporarily bond a little flowable composite resin onto the labial surface to provide an undercut for the clamp to engage. Etch for just a few seconds, if at all, and the resin will flick off later. A reader of the book How to Build a Million Dollar Practice discovered the 'Silker-Glickman' clamp for isolating several teeth in a posterior area without the need for individual tooth holes in the rubber dam. He says it is a modified cotton roll holder, and avoids the time-consuming 'hole for each tooth' technique. He orders ten at a time from Dr Edward SIlker's website, at $12 each. Google the name. Always use small stainless steel files, such as No 8 or No 10, and pre-curve the tips, before initial root canal negotiation and exploration. This will avoid blocking, stripping and ledging, will maintain canal anatomy and help avoid breakages. If your restored root canal will be accommodating a post later, consider heating out the gutta percha immediately after placement. This will allow you to gently apply further condensation. It will also avoid the risk of causing micro-cracks and possible leakage if you heat out the gutta percha at a later appointment. Removing all excess sealant from the access cavity of your completed root canal treatment can be tedious. Fit a suitable tip to your ultrasonic scaler and turn the water supply off. Now flood the access cavity with a stream of alcohol, delivered by a disposable 5 ml, syringe and activate it with the scaler tip. Use a sucker to remove the overflow. The result will be a very clean access cavity. When posts are cemented into post canals, retention will be greater if the post's surface area is greater. Before placement, air-abrade the post to roughen the surface and create a matte finish. This will provide micro-mechanical retention of the composite to the post. When taking impressions for a child for the first time, take an impression of their thumb first. This will accustom them to the sliminess, coldness and setting process of the alginate, and will ensure better cooperation when the actual impression is taken. You can pour the thumb at the same time as the impression, and give it to them at the next appointment. They will be very impressed, and show their friends. Visine eye drops contain a vaso-constrictor, and can be used to impregnate gingival retraction cord when gums are bleeding. You can use local anaesthetic solution for the same purpose. clinical hints
ADA News Bulletin May 2011
ADA News Bulletin July 2011