Clinical
BARD clinical tips R
emoval of a crown or bridge may be necessary for endodontic or cosmetic reasons,
but is often an unwelcome challenge for both dentist and patient. The use of rotary instru-
ments can risk damage to the supporting tooth and frequently results in the complete destruction of the restoration. This procedure can also be costly in terms of time and equipment, as burs and contra-angle handpieces undergo intense wear and tear. The WAMkey offers a less invasive technique for the
removal of crown and bridge- work. The kit comprises a set of three keys with oval-shaped tips, ranging in size from 2.5 to 5mm (Figure ı) To use the device, a four-step
protocol is recommended: ı. First, a small window is drilled in the crown using the appropriate bur (Ceramomet- alivore bur, Swallow Dental). The window is prepared to a diameter of ı-2mm at the area where the interface between the preparation and crown occlusal surface is assumed to be located. To account for the differ-
ences in occlusal reduction, the preparation should be made
closer to the occlusal surface for gold crowns, and about halfway between the occlusal surface and the margin for all-ceramic or ceramo-metal crowns (Fig 2). 2. The next step is to locate the stump/crown occlusal interface. It is likely that the dentist will locate this interface in Step ı, in which case he/she can directly proceed to step three. However, in some cases,
the opening will have to be progressively enlarged until the cement seal becomes visible. (Fig 3). 3. Create a tunnel between the occlusal surface of the prepa-
Using a WAMkey makes crown removal simpler, says Stuart Campbell
ration and the inner side of the crown. Using a cylindrical bur (approximately ı.2mm in diameter), the dentist drills an oval-shaped tunnel between the occlusal surface of the preparation and the inner side of the crown. The difference in
hardness between the dentine and the crown material will guide the dentist with regard to dentine penetration. This technique allows the crown to be reused following a simple repair procedure (Fig 4). Verify the depth of the
tunnel using a rubber-stop inserted onto the smallest
48 Scottish Dental magazine
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