Insight 18 — Vertical Finish Line; When There Is No «Line»
A brief clinical explanation
In BOPT, the finish line is not a «fixed line»; rather, it is a zone that is defined later. This logic can be applied adaptively, apart from the full BOPT philosophy, in some restorative situations.
In many cases, especially when one of the walls is involved with old amalgam or a subgingival restoration, defining a classic, precise finish line is practically impossible. Trying to create a defined chamfer or shoulder in these conditions often leads either to over-preparation or to biological violation.
While the other walls can be prepared with, for example, a standard slope-shoulder finish line, this particular wall has a different reality.
An important clinical point
When we do not have a «line», we define a zone instead.
On walls where an old restoration extends below the gingiva, using a vertical preparation with a knife-edge bur, instead of trying to create a defined finish line, is a conscious decision — not carelessness.
In this approach:
- instead of a finish line, a finish zone is created;
- the laboratory, considering the position of the other finish lines, the overall contour of the tooth, and the match with the adjacent teeth, can logically choose the final location of the transition.
Conclusion
This is not about performing BOPT. It is about borrowing the logic of the vertical finish line in situations where the wall is not definable.
Sometimes the vertical finish line is not a complete biological philosophy, but an adaptive geometric tool for preserving tissue, controlling the preparation, and avoiding a forced error.
When the clinical conditions do not allow a classic finish line, turning the «line» into a «zone» is a mature and defensible clinical decision.
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