The actual procedure depends, as you would expect, on which treatment is being provided. The most common procedure in general dental practice would be a surgical one providing access for deep cleaning and repositioning the gum to reduce pocket depth and make cleaning easier.
The area of the mouth to undergo surgery will be made numb. This may require a couple of injections depending on the site.
A flap will then be raised to expose the area in question i.e. your gum carefully cut with a scalpel and pushed back. Some cleaning and reshaping of the bony pocket will then be performed with the normal hand instruments or ultrasonic scaler and the flap sutured back into place.
Treating posterior (back) teeth is always more difficult and some level of shrinkage of the gum always occurs. On occasions this causes the loss of a portion of the gum in-between the teeth, we call this the 'inter-dental papilla'. This maybe an aesthic problem for you to consider. It is however worth remembering that when this shrinkage causes a reduction in pocket depth, it represents a transition to a healthier mouth that you can keep clean more effectively. As your gum shrinks inter- dental brushes
will become very important in keeping these gaps clean.