Managing Open Interdental Spaces With Indirect Veneer Restorations: Provisional Fabrication (Part 3)By Robert Winter on May 18, 2020 | comments
This is the third in a series of articles on managing open interdental spaces, diastemas, or black triangles, using a convex restorative form.
- In Part 1, I addressed the interproximal gingival margin location relative to the initial sulcus depth.
- Part 2 focused on the interdental margin location relative to the interdental contact.
This part examines using provisional restorations to guide and support papillae.
To have predictability in establishing the correct interdental gingival embrasure, provisional restorations must be contoured correctly to guide, shape, and support the papilla.
When the provisional restoration is removed from the teeth, the papilla should be “standing proud.” The veneer restorations are efficiently tried in to determine if the interdental contact touches the tip of the papilla and must be done immediately before the papilla slump.
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The proper subgingival contour and gingival embrasure are essential to guiding papilla creeping incisally. Incorrect provisional fabrication can be the result of:
- Not providing the appropriate convex form needed to decrease the volume of space between the teeth
- Creating excessive contour, which inhibits papilla movement incisally
- Making the interdental contact in the provisional too long gingivally, which will impede papilla creep incisally.
Excessive contour and not placing the gingival aspect of the contact far enough incisally closes the gingival embrasure. This is the most common error made in the fabrication of the provisional restoration. Doing so prevents incisal creep of the papilla.
When properly contoured provisionals are inserted, there should be black triangles. These black triangles create the space necessary for the papilla to fill in. The reasons for this space must be thoroughly explained to the patient because they generally expect the spaces will be closed and the triangles eliminated.
I instruct patients to brush their teeth, but not to floss. If a floss threader is used to pass dental floss through the gingival embrasure, it may traumatize the papilla. Also, I have my patients apply AO Gel (PerioSciences) to help maintain soft tissue health and reduce bacteria and plaque formation on the provisionals.
Provisional restorations are generally fabricated after gingival retraction and final impressions. This reflection of the gingiva displaces the tissue facially and distorts the papilla. I use 1.5 mm copyplast to fabricate the bisacryl provisional. Isolate and dry the teeth before placing the copyplast loaded with bisacryl over the prepared teeth.
If there is a common path of draw with all the preparations, I allow the bisacryl to auto cure. Once cured, remove the provisional from the mouth and clean with alcohol to assure there is no remaining oxygen inhibited layer. The flash remaining on the facial and lingual aspect should be extremely thin. Trim to the margin with your usual technique.
Interproximal trimming and shaping
Interproximal trimming and shaping are critical to provide space for the papilla. A diamond disc can be used for initial contouring. A speed of 10,000 to 20,000 rpm is generally recommended. Because it is a diamond-covered disc, it cuts extremely efficiently and leaves a rough surface. A flexible disc allows for flexing necessary to establish the desired convex contour. After using the disc, the surface needs to be polished in two steps with medium and fine rubber wheels.
I prefer not to use a diamond disc because it tends to be too aggressive. I use a green rubber knife-edge wheel (Brasseler USA, RW GPP). It is V-shaped when new or it can be “trued” with a diamond stone. This rubber wheel is used at a maximum speed of 8,000 rpm. It cuts bisacryl efficiently and more safely than a diamond disc, and cuts, shapes, and pre-polishes in one step.
After using the green shaper/pre-polisher, use the pink rubber wheel (Brasseler USA, RW PPP) to achieve the desired final polish. An alternative technique is to lightly air particle abrade with 50-micron aluminum oxide, clean, and apply Optiglaze (GC America). Optiglaze is a nanofiller light-cured resin for indirect restorations. Care must be taken to prevent the Optiglaze from pooling and filling in the previously established optimal contours.
The wider the space to be closed with the papilla, the more critical the contouring of the provisional. A convex shape is established on both surfaces to decrease the volume of space. The shape should be a “V” with curved sides. Do not error in making it U-shaped. The gingival embrasure needs to come to a point for the papilla to creep to its maximum potential.
When establishing the gingival embrasure height, place it 0.5 mm to 1.0 mm more incisal than the anticipated papilla height. Remember, you previously positioned your margin in the sulcus at a specific depth based on how far you anticipate the papilla to creep incisally. You, therefore, know what height needs to be established to the gingival embrasure. Always give slightly more room for height than you anticipate so you do not impede the papilla creep.
After contouring and polishing the provisionals, try them onto the prepared teeth to confirm the correct gingival embrasure has been established. Measure the distance from the interproximal margin to the contact. This must be slightly greater than the anticipated papilla creep. The provisional is then cemented or bonded using your normal protocol.
The key to the predictability of closing open interdental spaces in the final restorations is ensuring the provisionals are properly contoured to shape the papilla. The provisional restorations should be evaluated between two to four weeks after insertion to assess the papilla.
Confirmation of establishing a normal 2.5 mm interproximal sulcus depth is essential before the laboratory technician begins to fabricate the definitive restorations. A photograph of the provisional and an impression to make a cast are extremely valuable pieces of information to provide to technicians.
Part 4 in this series will address necessary communication with the dental technician to accomplish the correct restorative contours.
Robert Winter, D.D.S., is a member of Spear Resident Faculty.