14. Dls Flashcards
means establish for the time being,
interim
it must terminate the finish line and not in the grounds which will cause inflammation
TEMPORARY RESTORATION
→ check anatomy and health of tissue
→ if inflammation is present, the final crown cannot be installed
right away
TEMPORARY RESTORATION
protect pulp for a vital tooth
o if we leave it exposed, patient may feel sensitivity because of dentinal tubules
BIOLOGICAL
→ maintain periodontal health
o overhang and excess cervical areas must be removed to
prevent inflammation
BIOLOGICAL
→ provide occlusal compatibility
o there should be no contacts or interference when the patient bites on it against opposing tooth
BIOLOGICAL
→ maintain tooth position
- tooth is anchored by periodontal ligament
- there might be instances where the tooth will move; once it moves, there will be a hard time inserting crowns or bridges
→ protect against fracture
BIOLOGICAL
resist functional loads
MECHANICAL
→ resist removal forces
o design of reduction
MECHANICAL
→ maintain inter-abutment alignment
*contact areas must be maintained, spaces that are lost must be regained by the temporary restorations and maintain alignment
MECHANICAL
→ easily contourable
→ color compatibility
→ translucency
→ color stability
ESTHETIC
These things will overlap and there is an optimum interim restoration when all are satisfied
ESTHETIC
mold cavity is created by two correlated parts:
*External Surface Form (ESF)
* Tissue Surface Form (TSF)
→ external contour of the crown
→ what you see (anatomy, size, and shape of the temporary
restoration)
EXTERNAL SURFACE FORM
EXTERNAL SURFACE FORM has (2) categories:
o Custom
o Preformed
is a negative reproduction of either the patient’s teeth before preparation or a modified diagnostic cast
CUSTOM
maybe directly obtained with any impression material (irreversible hydrocolloid and silicone are convenient)
CUSTOM
easy accurate reseating done by trimming the thin areas of
impression material (interproximal or gingival margin)
CUSTOM
True or false
various preformed crowns are available commercially
True
→ choose one which will fit the tooth that is to be prepared
→ after restoring the teeth, you can use the vacuum type of template (transparent)
o place cast on a vacuum machine → template
o after reduction of abutments → temporary crowns using template
PREFORMED
→ baseplate wax can be used as it is more convenient and economical but more complicated
→ some people make escape holes so that when injected there are no bubbles
PREFORMED
→ most crown forms need modifications: internal relief, axial re-contouring, occlusal adjustment in addition to lining procedure
→ generally limited to use as a single restoration because it is not
feasible to use them as pontics for FDPs
PREFORMED
→ has the most natural appearance
POLYCARBOXYLATE
available in single shade (monolithic)
POLYCARBOXYLATE
cervical to incisal has a different hue and chroma but this only
has one shade
POLYCARBOXYLATE
→ available for incisors, canine and premolar teeth (not for molars)
→ limited use
POLYCARBOXYLATE
True or false
polycarbonate crown forms are more tolerable, selected to
establish contact areas
True
→ crown form consists of thin, soft, and transparent material
→ becomes a shell
CELLULOSE ACETATE
→ size and shape can be selected from a mold guide
→ crown form is trimmed and festooned to fit the preparation without impingement on the soft tissue
→ available in all tooth types
CELLULOSE ACETATE
True or false
shape will not conform the cellulose acetate
False
(shape WILL conform the cellulose acetate)
suitable for posterior teeth since it is colored
ALUMINUM
→ have anatomical shaped occlusal and axial surface (ridges can
be seen)
→ care must be taken during try in verification of their delicate
margins
ALUMINUM
→ adapt the margins to the finish line
→ as it is highly ductile, it allows easy contouring to conform to the
shape of the finish line
ALUMINUM
available for posterior teeth
TIN-SILVER
→ alloy (mixture of tin and silver) is very soft and the margin of
the crown can be flexed prior to the seating with a swaging
block
→ can be contoured since it is flexible
TIN-SILVER
Produce a close marginal fit after the shell is trimmed with a bur
TIN-SILVER
→ fit will depend on how you form and contour so that it can sit on the finish line
→ rest of the surfaces should also be lined with acrylic resin (self-cure) to provide good internal adaptation and retention of the temporary restoration
→ modify the cervical (contour or cut) to fit the prepared abutment
TIN-SILVER
→ used in children with extensively damaged primary teeth
→ cannot be altered with resin
NICKEL-CHROMIUM
→ crowns can be easily re-contoured using pliers
→ indicated for long-term interim restorations
NICKEL-CHROMIUM
→ prepared tooth surface and edentulous ridge (when present) → more concerned with what’s in contact with the tissues
→ shape of crown in cervical, labial, and lingual areas
TISSUE SURFACE FORM
TISSUE SURFACE FORM has (3) categories:
o Indirect
o Direct
o Indirect-direct
o Indirect
o Direct
o Indirect-direct
made by the lab
“custom”
not in the patient’s mouth
“indirect”
technique involves fabrication of the interim restoration outside the mouth
CUSTOM INDIRECT PROVISIONAL RESTORATION
ADVANTAGES
→ no contact of free monomer with the prepared teeth or gingiva which might cause tissue damage and an allergic reaction or sensitization
CUSTOM INDIRECT PROVISIONAL RESTORATION
ADVANTAGES
→ the technique avoids subjecting prepared tooth to the heat evolved from the polymerizing resin
CUSTOM INDIRECT PROVISIONAL RESTORATION
ADVANTAGES
indirect technique produces restoration with a superior marginal fit and as an auxiliary is involved in fabricating the restoration in the lab, it frees the patient and dentist for considerable amount of time
CUSTOM INDIRECT PROVISIONAL RESTORATION
the technique produces a custom made preformed external surface form of the restoration but the internal tissue surface form is formed by the underprepared diagnostic casts–lesser than the ideal
CUSTOM INDIRECT-DIRECT INTERIM RESTORATION
ADVANTAGES
→ with the combination indirect-direct technique, chair time can be reduced since the provisional shell is fabricated before the patient’s appointment
CUSTOM INDIRECT-DIRECT INTERIM RESTORATION
ADVANTAGES
→ enhanced control over restoration contours minimizes the time required for chair side adjustments
CUSTOM INDIRECT-DIRECT INTERIM RESTORATION
ADVANTAGES
smaller amount of acrylic resin will polymerize in contact with the prepared abutment, resulting in decreased heat generation, chemical exposure, and polymerization shrinkage compared to the direct technique
CUSTOM INDIRECT-DIRECT INTERIM RESTORATION
DISADVANTAGES
→ the disadvantage of this procedure is the potential need of a laboratory phase before tooth preparation and the adjustments that are frequently needed to seat the shell completely on the prepared tooth
CUSTOM INDIRECT-DIRECT INTERIM RESTORATION
DISADVANTAGES
potential tissue trauma from the polymerizing resin and inherently poorer marginal fit
o these resins produce heat when setting
CUSTOM INDIRECT-DIRECT INTERIM RESTORATION
DISADVANTAGES
→ therefore, the routine use of directly formed interim restoration is not recommended when indirect techniques are feasible
CUSTOM INDIRECT-DIRECT INTERIM RESTORATION
