Preoperative
Treatment Procedure:
- Take preoperative elastomeric impressions of the arches. Construct
maxillary and mandibular study models. Take a bite registration and
mount the casts.
- Send both casts to the laboratory. A thoroughly detailed laboratory
prescription denoting which teeth are to be crowned, extracted and/or
bridged; selected shade and interocclusal registration should accompany
the case. A diagnostic wax-up or analyses of required modification can
also be included.
- Technician will duplicate the master model and use the duplicate cast
to formulate the provisional restoration(s). The original cast serves
as a continuing reference for tooth contours, anatomy, texture and gingival
architecture.
- The duplicate model will be adjusted by the dental technician to agree
with the prescription. Preparation of the crowns and hollowing of the
appropriate denture teeth is performed in a controlled manner to allow
ample room for easy seating with cold cure acrylic.
Chairside Adjustments
and Modifications:
- Ensure coverage of tooth preparations and proper embrasures are established.
This will eliminate black spaces and encourage gingival health. Use
a sandpaper disk to open embrasures that need to be extended and to
trim off excess acrylic from facial and lingual aspects. An acrylic
bur will quickly shave off larger amounts of excess acrylic.
- Try in provisionals periodically to check gingival embrasure extensions
and to make occlusal adjustments.
Relining Technique:
- Prior to tooth preparation, review the extent of tooth reduction on
the duplicate cast to identify the incisal, lingual, facial, mesial
and distal aspects along with the extent of gingival reduction. Final
tooth preparation must be accomplished within these dimensions to ensure
proper fit of provisionals.
- Anesthetize area.
- Prepare the teeth and remove any failing restorations or carious tooth
structure.
- Restore missing tooth structure with an appropriate dentin adhesive
and composite (or cast metal post and core, if indicated).
- Fully seat the provisional over the crown preparations. If incomplete
seating occurs, use contact spray fit-checker or rock the provisional
at one end and then the other to identify the tooth that is binding.
Reduce that tooth or adjust areas of impingement inside denture tooth
with an acrylic round bur. Check the contacts with dental floss or articulating
paper. When seated properly, check occlusion by having the patient bite
with the restoration in place.
- Isolate the teeth and retract the soft tissue with a cord. Apply a
separating medium to the surfaces of all prepared teeth (including the
embrasure areas) to prevent cold cure acrylic from adhering.
- Using a round bur at low speed, carefully abrade all internal areas
of the provisional and a 1 to 2 mm surface rim along the external margin
of any deficient marginal area.
- Lightly coat all surfaces of the provisional to be relined with monomer.
Thoroughly mix the selected shade of acrylic to a medium consistency
and fill the provisional with enough acrylic resin to allow complete
seating.
- Wait until the resin sheen has disappeared (i.e., no free monomer
on the surface), then seat the provisional over the lubricated preparations.
- Remove the provisional when the acrylic resin is rubbery ( 50% set)
and quickly trim away excess reline material with sharp scissors or
composite instrument. Re-seat provisional. Remove the provisional just
prior to complete set and let final polymerization take place. Moving
the provisional on and off the preparations will prevent possible engagement
of undercuts on prepared or adjacent teeth that could lock the restoration
in place.
- Place provisional back on prepared teeth. Re-contour, shape, finish
and polish margins. Focus on the emergence profile, seamless marginal
interfacing, concave proximal contours, periodontal access for oral
hygiene and a high surface polish for plaque resistance.
- Reinsert the provisional and reline any inadequate area, taking care
to lightly abrade the surface for optimal adhesion.
- Check the occlusion and adjust if necessary. Make final esthetic modifications
in contour, length, embrasure definition and incisal silhouette. If
any external area has become rough, reseal with light-cured composite
resin sealant and polish the surface.
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