Thin bone crest?
No longer an issue.

New Split Crest technique

Three conical D.R. Expanders, with an increasing diameter and depth notches.
The method includes another 4 drills with different diameters, essential to create a calibrated centring well. This is required to ensure D.R. Expanders 1 - 2 and 3 can rotate safely and allow for gradual yet natural bone expansion.  

Clinical Indications
The special star shape with six reverse cutting edges will tend to drive back the bone without removing material and, thanks to its conical shape, it will force bone tissue to gradually take on a convex shape.

The D.R. Technique (patent)  
dr. Denni Rondinini

The D.R. Technique will enable you to position implants with just 2, 3 mm thick crest:
2, 3 mm thick bone crest Use of D.R. Expanders.
D.R. Expanders use. 
Split Crest obtained whilst maintaining vestibular and lingual bone thickness.