Frustrated with Rough Margins and Preps?

I'm sharing my biggest TIP to get smooth margins FAST! I know how frustrating it is to spend time refining the margins to then look at the models of the preparations and see how rough and jagged they are. The literature tells us that rough margins are difficult for the ceramist to visualise where to place the finishing line leading to poor marginal fit. If the marginal fit is poor, this will lead to over-contoured restorations, periodontal problems, marginal gaps, staining and recurrent caries.

A case can be made that with posterior full coverage restorations that rough margins and preps is not a problem. However, in the aesthetic zone and in particular porcelain veneers, excellent marginal fit and a smooth preparation is critical for success.

Over the last 20 years, I've tried EVERYTHING to achieve the smoothest preps and margins. I'm going to let you know right now, the biggest secret to achieve the smoothest preparations - A speed increasing electric handpiece. There are 3 reasons why:

1. Accurate speed - with an electric handpiece you can have full control of the speed at which the bur spins. When you have a speed increasing handpiece of 1:5 you can adjust the speed accurately from 450 - 200,000rpm. Air turbines have one speed only - 400,000 rpm.
   
2. High torque - the bur will never slow down or stop no matter what material you're cutting at any speed. 
3. Steadier cutting technique - air turbine handpieces will always slow down or even come to a halt when you encounter something hard. And the work around to overcome this? You have to use an 'on-off-on' feathering movement to prepare teeth. This movement means that you have to constantly move your hand and your handpiece which makes it extremely hard to have any control. This alone is one of the biggest reasons for forming jagged margins.

I know making the switch from air turbine to electric handpieces can be daunting, but I hope after reading this information, the seed has been planted to start the switch.