The tooth preparations for the subsequent restorations of fixed prosthesis mainly differ in two main types: the preparations with defined margin and the preparations without a defined margin.

Preparations can also be classified in relation to the gingival margin. Being supraginigvales whichever is carried out slightly above the gingival margin, juxtaginigvales which are obtained at the same level as the gingival margin and, finally, subgingival preparations that are made slightly below the gingiva margin.


Abbreviations BOPT prevent from english biological oriented preparation technique which stands for biologically oriented preparation technique.

This is a (vertical) tooth preparation technique for a definitive indirect restoration without a termination line in the area within the gingival sulcus, thus mimicking the anatomical crown of the tooth.

By later modeling the provisional and cementing it slightly within the gingival sulcus, a non-cemental line of the prosthesis is achieved in which the gingiva adapts.


The BOPT technique allows a correction of the anatomical union between enamel and cement in teeth that have not been previously prepared and with it it is possible to eliminate termination lines in teeth that were already prepared. In addition, thanks to this technique there is the possibility of repositioning the end line of the prosthesis at a different level controlling the biological space, with this being able to level the emergence profiles of the gingiva since through this technique the gingiva adapts, giving rise to greater gingival stability in the medium and long term. So you get a optimal marginal fit of the area between the restoration and the tooth.


This type of tooth preparation for a fixed restoration is recommended in patients who need to obtain a biological advantage from the tissues.

It is recommended to perform the BOPT technique in the following cases, mainly in the first:

  • Existence of less than 3 millimeters of keratinized gingiva, when the gingival biotype is thin or also if it is of a darker hue.
  • In a retreat of a horizontal carving. That is, when the tooth in which it has already been previously prepared must be re-prepared.
  • When there is no ferrule, that is to say a “grip” for the fixed prosthesis. Using the BOPT technique, it is performed 0.5 millimeters from the gingival margin, achieving more stability.



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