Prep Guides

Veneer Preps

 

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An alternate veneer prep is, a slice-prep.  The slice-prep requires the removal of the contact area and is carried lingually (through the contact) to the lingual proximal line angle.  All other specs are the same as the standard veneer prep.  General rules as to when one would or would not use slice-prep:

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  • Use a standard prep when existing tooth contact areas are in the correct position.
  • When a slice-prep is required on one side of a tooth, it is not mandatory to slice-prep the opposite side of that tooth.
  • When a slice-prep is proper on a surface of a tooth, it is usually necessary to slice-prep the surface of the adjacent tooth.
  • Do slice-prep on proximal surfaces when closing diastema or black triangles.
  • Do slice-prep when changing golden proportion.
  • Whenever in doubt, do slice-prep.

There are additional preparation considerations based on the case type.  We can classify these as severe color correction (tetracycline staining), diastema, and instant-ortho type cases.

For severe color correction, we use standard veneer preparation design with increased buccal reduction.  That is, providing the original tooth placement and sizing was correct.  Instead of .8mm, we will need 1.5mm buccal reduction.  Additionally, if the dentin or enamel staining is severe at the soft tissue margin, it is advisable to prep about .3mm sub-gingival.

For diastema (and black triangle) correction, we must first determine the number of teeth to include so that golden proportion can be achieved in the final case.  As a rule of thumb, if the combined diastema spacing is less than 2mm, we can correct this with two units.  If the space is from 2-4mm, we should include a minimum of four teeth.  Spaces greater than 4mm require a minimum of six teeth for esthetic results.  When treating two teeth, it is necessary to do slice preps on the surfaces that are being relocated to close the diastema.  Standard preps can be done on the opposite side.  Treating four teeth (#7-10) will require slice-preps on all surfaces, except distal of #7 and #10.  Furthermore, reduction on the opposite side of the diastema should be maximized.  We are happy to provide (at no charge) a written preparation guide for individual cases.  Please forward  a set of study casts prior to tooth preparation, for this service.

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Instant-ortho cases will most likely require both standard and slice-preps on specific surfaces.  The potential number of possibilities of tooth positions are too numerous to describe. As a result, it is always best to obtain a written prep guide from us (as described above).