Temperature increase during removal of incisal extensions on resin-bonded castings

To assist seating or relocation of resin-bonded retainers on abutments, extensions of the cast framework can be incorporated and removed after cementation. There has been apprehension concerning the heat created during the grinding of these extensions, particularly if there is a substantial bulk of metal. This study recorded the elevation of temperature when cast incisal extensions were removed by grinding after cementation. A total of 20 retainers were waxed for 0.3 mm thickness, cast in a nickel-chrome alloy, and bonded in-vitro to an acid-etched natural tooth with composite resin cement. The temperature of the coronal dentin was measured while the tag was ground with a high-speed dental handpiece. The maximum temperature and mean temperature elevations that exceeded the resting temperature were recorded. A significant temperature rise was apparent when complete incisal wrapover framework extensions were reduced compared with the removal of fingerlike locating extensions. In conclusion, care should be exercised when the locating extensions of resin-bonded retainers are removed with high-speed dental handpieces.