I/O Scan and Prep Technique - Dr. Brandon White, DDS

Begin with the end in mind." We hear that phrase all the time with regard to case planning and execution, and when Mark asked me to do a follow up on my technique for making a VPS impression, I immediately thought about how that "end" of my prep appointment is only the beginning for the Lab to make our true ending a success. Visualizing the outcomes we want as clinicians allows for a more predictable restorative process, which can be translated into a more predictable (and efficient) prep appointment. It is my opinion that most dental programs still teach prep design to a Board Exam standard, doing us as future practitioners a disservice. While mine is not a perfect system, my approach works well in my hands. The best part: it works with traditional impressions or intraoral scanning. 


  • Step one: Visualize exactly where you want the margin to be. This should be one continuous path around the tooth, and you should visualize how YOU want it to look - chamfer, shoulder, deep chamfer, or disappearing chamfer, even a knife edge margin. 

  • Step two: Rough prep that margin. I wish I could tell you which bur I prefer for this, but I will use a myriad of black stripe, round-end, tapered diamonds. I generally keep three on my block - a short, a medium, and a long diamond, and generally break my contacts first, then connect the dots. 

  • Step three: Remove any decay or existing defective restorative material remaining. Reduce the occlusion following the material guidelines you intend to use. If I am in doubt, I will use a 330 bur to make occlusal reduction guides in the occlusal. If I am prepping the lingual of an anterior tooth, I will use the width of my prep diamond to make guide lines.

  • Step four: Pack your first cord. Make sure you've removed all decay. Fill in any undercuts/boxes/place a core as indicated.

  • Step five: Refine your margin and occlusal reduction. 

  • Step six: Place your second cord. I prefer size 2 cords for molars and most 2nd bicuspids, and size 1 cords anterior to the second bicuspid.

  • Step seven (skip if impressing with VPS): Scan the prep arch and assess your occlusal clearance on the scans. You can visualize this on a scanner such as iTero as soon as you have made a bite registration scan.

  • Step eight: Refine the margin if you've noticed any areas to improve while scanning and reduce occlusion if needed.

  • Step nine: Pull the second cord, rinse thoroughly if impressing, air dry, scan the prep (or impress). 

I am by no means a fast dentist, and I take a lot of time making my preps as ideal as possible, but patients care about speed and efficient appointments. Experimenting with your prep sequencing and design combined with utilizing intraoral scanners has the potential to drastically improve the quality of care we can deliver and our patients' understanding of that care. As with impressions, any questions are welcome. Happy prepping and scanning. 

Brandon White, DDS

I want to express my sincere thanks to Dr. Brandon White for sharing his skill and knowledge in an efforts to help the southern Oregon dental community pursue excellence in dentistry.

Mark Hidde - CDT, Owner