Treatment planning is key to determining the proper preparation design needed for a successful esthetic and functional outcome. Furthermore, when you are ready to implement your treatment plan, outcome-based preparation design is the most important process dentists can integrate into their practice. It provides them with the tools to achieve not only esthetic success, but more importantly, it allows them to predictably accomplish all of their treatment goals and meet or exceed patient expectations. 

In addition, outcome-based preparation design allows dentists to establish proper function and create adequate material thickness to produce a durable restoration. Without carefully planning before they begin to prepare a tooth, they take a chance that the result achieved is not the one they and their patient desired or expected.

The goal of restorative dentists is to mimic or replicate tooth structure using composite or ceramic while having a positive influence on the gingival tissue. This should be accomplished using the least invasive procedures required to meet the esthetic and functional goals of the case. In many cases, without an interdisciplinary approach to treatment, restorative treatment may become more extensive than required. For example, you or your restorative dentist should always consider whether orthodontic therapy, as a treatment adjunct or alternative, could minimize the degree of tooth reduction required. If the patient's only goal were lighter- and brighter-appearing teeth, you should consider whether bleaching would allow you to use a more conservative approach to tooth preparation. If isolated or minimal changes are planned, it is best to consider whether direct restorations could accomplish the treatment goals before proceeding to a more invasive indirect restorative option. 

If you do determine that tooth reduction is necessary, the amount of reduction needed will be dependent on not only clinical techniques, but also the laboratory’s process for restoration fabrication and the restorative materials that are selected. Always consider an additive technique to minimize the actual tooth reduction. However, this will add volume to the tooth, which may or may not be clinically acceptable depending on the patient's needs. 

The following are five steps dentists should take as part of the outcome-based preparation design process:

1. A clear vision of the treatment goal is developed and a comprehensive diagnosis and treatment plan is completed. 

2. A diagnostic wax-up is completed, which precisely represents the desired treatment outcome

3. Treatment aids are made from the diagnostic wax-up. They include:

  1. Silicone preparation reduction guides that will be used for pre-mockup preparation of the teeth to prevent distortion of the copyplast when making an intraoral mockup. It also confirms the amount of tooth reduction and subsequent space required for the restorative material. Types of silicone reduction guides include:
    1. Labial: shows labial reduction
    2. Palatal: shows length reduction
    3. Window: shows labial and palatal reduction in a horizontal perspective
    4. Vertical: shows labial and palatal reduction in a vertical perspective
  2. Copyplast (1.5 mm), used for:
    1. An intra-oral mockup that will represent the definitive size, shape and positon of the restorations.
      1. Depth cuts will be made into the mockup to control the preparation.
      2. Provisional fabrication

4. Pre-preparation completed before the intra-oral mockup.

  • This is essential to ensure that the mockup is as accurate as possible.
  • This initial preparation eliminates tooth structure that prevents the copyplast used to make the mockup from seating passively or without distortion.

5. Precise depth cuts are made. 

  • Precise depth cuts into the tooth or mockup will ensure there is adequate space for the thickness of restorative material required to accomplish the treatment goals. 

When a dentists uses an outcome-based preparation design process, it will improve treatment outcomes and lead to increased patient satisfaction. For more on preparation design, see my previous article on the 10 factors that influence or determine the preparation design.

Dental preparation design: confirmation of desired tooth reduction

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Bob Winter, D.D.S., Spear Faculty and Contributing Author