Which statement about rest seat design on posterior teeth is incorrect?

The statement regarding the preparation sequence that is identified as incorrect highlights a fundamental aspect of effective dental restorative design. In the context of rest seat design on posterior teeth, the proper sequence of preparation is crucial for achieving a functional and esthetic outcome in restorative dentistry.

When creating rests, it is generally advisable to establish guide planes first before completing the rest seat preparations. The purpose of guide planes is to provide a defined path for dental prosthetics and ensure proper alignment and seating of the restoration. Completing the guide plane preps prior allows for a better assessment of the available space and clearance needed for the rest seats. This sequencing prevents unnecessary alterations or adjustments to the rest seat after guide planes are placed, which could complicate the overall restoration process.

The other statements regarding rest seat design hold true principles of restorative dental practice. For example, the base of the triangular rest indeed lies at the marginal ridge, which is integral to the stability and distribution of forces on the dental arch. Maintaining an angle of less than 90 degrees between the seat floor and the proximal surface aids in ensuring proper seating and retention, while the use of round burs typically increases the likelihood of creating undesired undercuts, which can complicate the fitting of prosthetic components. Understanding these principles is essential