Prosthetic Fabrication & Fitting Flashcards

Which platinum catalyst system is most commonly used to vulcanize addition-cured (condensation-free) silicone for facial prostheses?

Answer: Platinum-based addition catalyst at body or room temperature

Platinum-catalyzed addition-cure silicones produce no by-products, offer excellent biocompatibility, and cure at room or mild elevated temperatures used in anaplastology.

In a magnetic retention system for an auricular prosthesis, the magnets are usually embedded in the:

Answer: Prosthesis base and the corresponding bar or cap on the abutment

One magnet set is encapsulated within the silicone prosthesis base and the opposing magnets are housed in keeper attachments on the implant bar or individual abutments.

During impression-taking for a mid-facial defect, a dentist's tray adhesive is applied to the impression tray to:

Answer: Chemically bond the impression material to the tray, preventing distortion on removal

Tray adhesive creates a chemical bond between the elastomeric impression material and the tray, preventing the material from separating or distorting when removed from the defect.

Extrinsic coloring of a cured silicone prosthesis is applied using silicone-compatible paints primarily because:

Answer: Silicone-based surface paints flex with the prosthesis and resist peeling better than non-compatible paints

Silicone-compatible extrinsic paints have the same elastic modulus as the prosthesis, so they flex without cracking and adhere longer than incompatible media.

A stock ocular prosthesis differs from a custom-fabricated ocular prosthesis in that the stock version:

Answer: Has a pre-formed, standardized shape not individually contoured to the patient's socket

Stock prostheses come in pre-made sizes and iris colors and are not custom-fitted to the individual socket anatomy, often requiring more frequent adjustment and less optimal comfort.

When mixing pigments into platinum silicone, the anaplastologist should avoid iron oxide pigments that are contaminated with sulfur compounds because sulfur:

Answer: Acts as a platinum catalyst inhibitor, preventing proper cure

Sulfur-containing compounds and certain amines inhibit platinum catalysts, resulting in a tacky or uncured silicone surface even after extended vulcanization time.

The primary advantage of using a bar-retained overdenture design for a maxillofacial prosthesis is:

Answer: It splints multiple implants, distributing occlusal and retention forces across all fixtures

A connecting bar rigidly splints implants, spreading functional loads and improving prosthesis stability compared to independent abutment attachments.