6.4 Direct and Indirect Provisionals

What provisionals do and the RDA's legal authority to make them

A provisional (interim) restoration covers a prepared tooth while an indirect restoration is fabricated. It protects exposed dentin and pulp, prevents the prepared tooth and antagonists from drifting, maintains the gingival contour, preserves esthetics and phonetics, and lets the patient chew. Because patients live with provisionals for days to weeks, fit and finish matter even though the restoration is not final.

California gives the RDA real authority here. BPC 1752.4 permits the RDA to place, adjust, and finish direct provisional restorations and to fabricate, adjust, cement, and remove indirect provisional restorations, including stainless steel crowns when used as a provisional restoration. Fabricating a provisional crown is therefore an allowable RDA duty, performed under dentist supervision—one of the clearest examples of the RDA doing hands-on restorative work within scope. The dentist still prepares the tooth, diagnoses, and delivers the permanent restoration.

Direct vs. indirect provisionals:

Provisional materials and temporary cement

Two resin chemistries dominate direct provisionals:

• Bis-acryl (bis-GMA) composite dispenses from an automix gun into a matrix, sets quickly, is esthetic, low odor, and easy to trim—the modern default for many offices.
• PMMA (polymethyl methacrylate) is mixed powder/liquid (monomer), is strong and inexpensive, but is more exothermic (gives off heat as it sets, which can irritate the pulp—seat and remove to prevent locking, and use water cooling), shrinks more, and has a strong methacrylate odor.

Provisionals are seated with a temporary cement, almost always a non-eugenol type. Two reasons: the provisional must be removable at the next visit, and—just as with interim fillings—eugenol can inhibit the resin cement used to bond the final restoration. So the standard is non-eugenol temporary cement under a provisional that precedes a resin-cemented crown. The RDA prepares the provisional material, matrix or shell, trimming and polishing instruments, temporary cement, floss, and cleanup aids, then removes excess cement with a hand instrument as permitted.

Evaluating and finishing the provisional

A provisional is judged on the same features as a final restoration, and the RDA may finish and adjust direct provisionals under supervision:

Direct provisionals are time-sensitive. Bis-acryl and PMMA have working and setting windows; the matrix and prep must be ready before mixing. Lubricating the prep lightly and seating/removing the provisional during the rubbery stage prevents it from locking into undercuts and prevents heat buildup. A provisional that sticks, cracks, has a void, or is short at the margin is reported and corrected.

Indirect and preformed provisionals still demand chairside judgment: a lab temp or stainless steel crown must be adapted, the occlusion checked, cement cleaned, and the patient instructed on care—avoid very sticky foods, floss but pull the floss out the side rather than snapping up, and call if it comes off, feels high, or hurts. " None of these are dismissed; the RDA reports and assists with the directed adjustment. A provisional that leaves the prep exposed, sits high, has retained cement, or is loose is unsafe to send home—evaluate before dismissal.

Stainless steel crowns and the matrix shell methods

A stainless steel crown (SSC) is a preformed metal crown used in pediatric dentistry as a durable restoration and, on adult teeth, sometimes as a provisional—and California explicitly lists fabricating, adjusting, cementing, and removing SSCs used as provisionals as an RDA duty. The crown is sized to the mesiodistal width, festooned (trimmed) and crimped at the margins to adapt to the tooth, then cemented (commonly with glass ionomer for fluoride release and a chemical bond).

For direct chairused provisionals, several matrix/shell methods exist: a putty or alginate index taken before preparation reproduces the original tooth shape into which provisional resin is injected; a clear vacuum-formed shell does the same with light-cured resin; and preformed polycarbonate or aluminum crown forms are relined. Knowing that the matrix records pre-op anatomy explains why the dentist may take an impression before any drilling—the RDA prepares and labels that index so it is ready when the provisional is fabricated.

Each method ends the same way: trim, check margin/contact/occlusion, polish, cement with non-eugenol temporary cement, remove excess cement with a hand instrument, and instruct the patient.