Spin Me Right Round by Lori Trost, DMD

Dentaltown UK Magazine- Spin Me Right Round
by Lori Trost, DMD

Maximizing the use of diamond burs

Prepping a crown with a bur spinning in a high-speed handpiece at nearly 400,000rpm can be daunting. Aside from the challenges of navigating a patient’s curious tongue or tight cheek, specific burs are used to reduce tooth structure, create a margin and design a preparation worthy of a final indirect restoration.

Truth be told, dentists often struggle with prepping teeth, even if it is something the dentist does often. This is a reality for most doctors as crown and bridge procedures are the bread and butter in their practices.

With more and more all-ceramic restorations, clinicians need to be aware of material distinctions and minimum depth specifications before the lab technician calls and says there wasn’t enough reduction or the margin is in question.

But do we as dentists really understand how to properly use a bur? How can we get the most benefit from the bur design? When does the bur move past its cutting efficiency? Can I reuse a diamond bur? Is there a more straightforward approach when preparing teeth that is predictable while maximizing the cost effectiveness of a diamond bur?

Rigors and demands
Regardless of a single-use or multi-use diamond bur, several factors need to be taken into consideration to better understand a variety of clinical demands placed on a diamond bur’s performance.

Apart from an excellent performing high-speed handpiece, the clinical reality is, diamond burs are affected by the rigors of heat, vibration, drag, dehydration and chattering. These effects cause the diamond burs to lose their particles, change shape and become irregular. One of most common issues to be aware of is when the tip—the critical area clinicians rely on to form the margin of the preparation—goes bald. This issue with the instrument can lead to misshapen preparations.

These factors not only reduce the cutting quality and effectiveness, but ultimately create more trauma to the tooth. And, with repeated use, the process dramatically spirals downward causing even more frustration for the dentist.

Practical crown prepping tips

  • Here are some tips to ensure healthy and efficient crown preparations.
  • Measure twice, cut once. Use diamond burs to your advantage. Learn the dimensions of the burs and match those depths to the reduction you need. Now you not only have a cutting tool, but a measuring device as well. Your lab will appreciate your newfound consistency!
  • Maximize the bur’s cutting performance. Use multi-use burs for quadrant crown preparations and use single-use burs for single crown preps. Discard them once finished! Somehow as clinicians we trip over dollars to pick up pennies. Time is money in dentistry. And in this case, it also laterals over to patient safety.
  • Develop a methodical reduction approach. Move around the tooth in a constant direction. Back-and-forth motions often lead to stepping of the margin. Begin with a coarse grit for gross reduction and finalize with a fine grit diamond bur to create a smooth preparation. This has never been more important, especially with the adoption of digital impression capture. Hone it!
  • Allow your provisional to be a teacher. When fabricating your provisionals—or if your assistant is—make sure to evaluate for the proper thickness. If the occlusal is thin, the final restoration occlusal table will be too!
  • Use copious water when prepping. Water spray is an important variable when preparing a tooth. Not only does it cool the tooth, but it also minimizes clogging of the bur and lubricates the cutting process.

Closing
Using the right tools to do a neat job efficiently is necessary for tricks of the dental trade—with the goal being a healthy, safe and uniformly reduced tooth.

Dentists can agree that no matter what combination of burs or diamond rotary instruments is used to prepare any indirect restoration, they must respect and complement the procedure.

 


Case 1
A 24-year-old patient presented with a large, discolored composite buildup on #9 (Fig. 1). The tooth had been endodontically treated after the patient suffered a falling injury. The tooth was prepared for an all-ceramic crown (eMax) using a variety of three Solo Diamonds (Premier).

To begin, a modified shoulder, coarse diamond (#847018) was used to create facial depth grooves to ensure proper reduction. The interproximal areas were reduced using a flame-shaped diamond (#862012). Lingual reduction was achieved by a football-shaped diamond (#368023). The margin was finalized using a modified shoulder diamond and the preparation was smoothed using a generic composite polisher (Figs. 2 and 3). The Solo Diamonds were discarded.

As the treating dentist in this case, I enjoyed the fresh cutting efficiency of the Solo Diamonds. In my clinical experience, when reducing anterior tooth structure, cutting preciseness is paramount to be able to deliver an excellent final restoration.

  • Figure 1

  • Figure 2

  • Figure 3

 


Case 2
Case 2 A 52-year-old patient presented with the need to prepare a maxillary right second molar crown along with replacing an existing right first molar crown. Because two crown preparations were underway, multiuse diamonds (Two Striper 253SB) were utilized (Fig. 4).

Multiuse diamonds such as the Two Striper are an excellent choice for quadrant preparations because they maintain their cutting effectiveness throughout multiple crown preparations, allow for easy margin delineation, and reduce the number of times you need to change out the burs. The preps were finalized for zirconia specifications, the burs discarded and a final impression taken (Fig 5).

  • Figure 4

  • Figure 5

 


Author Dr. Lori Trost is a recognized educator, an ADA Shils Foundation Award recipient, and author of numerous articles in the areas of CAD/CAM technology, restorative dentistry, minor tooth movement and financial management. She lectures internationally in the areas of restorative and digital dentistry, cosmetic orthodontics, new diagnostics and anesthetics, along with creating cohesive dental teams. She is also a clinical researcher who maintains a private practice geared toward restorative dentistry.
 
Sponsors
Townie Perks
Townie® Poll
Have you placed an implant in the past 3 months?
  
Sally Gross, Member Services Specialist
Phone: +1-480-445-9710
Email: sally@farranmedia.com
©2021 Dentaltown, L.L.C., a division of Farran Media, L.L.C. • All Rights Reserved
9633 S. 48th Street Suite 200 • Phoenix, AZ 85044 • Phone:+1-480-598-0001 • Fax:+1-480-598-3450