Extreme care must be taken when grinding and polishing ceramic restorations. Excessive trauma, vibration or heat may cause microcracks to develop in the ceramic. The microcracks may propagate and lead to ceramic chipping or to the catastrophic failure of ceramic restorations.
Follow these steps to minimize the probability of cracks forming in your ceramic restorations. Keep in mind that electric handpieces are more efficient than air turbines because they maintain their torque at slow speeds.
Steps for adjusting ceramic restorations
- Use a slow speed friction grip handpiece operated at a maximum speed of 20,000 rpm. An example of this is the Brasseler TiMax X20L, which is a 1:1 ratio slow speed electric handpiece attachment.
- Use a fine or extra fine diamond bur only! A good example is Brasseler Dialite Diamonds 8369 DF 025 or 8369 DEF 025. (Figure 1)
- Use air and water spray to keep the diamond and ceramic cool.
- Use a light touch. Let the torque of the handpiece and bur do the cutting.
Steps for polishing ceramic restorations
- Use a slow speed latch hand-piece attachment run at a maximum speed of 10,000 rpm. An example of this is the Brasseler TiMax X25L. (Figure 2)
- Use a light touch to avoid generating heat.
- Use a medium grit rubber polisher for initial polishing. An example of this is Brasseler Dialite LD W18 MLD Knife, W17 MLD Cup, W16 MLD Point. (Figure 3)
- Follow with a fine grit rubber polisher for high sheen. An example of this is Brasseler Dialite LD W18 FLD knife, W17 FLD Cup, W16 FLD Point.
By following these steps, you will find that adjusting and polishing ceramic restorations is very efficient and induces minimal trauma to the ceramic.