The effect of sprue attachment design on castability and porosity

R. G. Verrett, E. S. Duke

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Sprue attachment design is an important and controversial variable that can affect casting characteristics of castability and porosity. Four sprue attachment designs-straight, flared, abrupt constriction, and gradual constriction-were investigated. Standardized wax copings simulating complete veneer metal ceramic crowns with knife-edge margins were sculpted on refractory investment dies, sprued, invested, and cast with Olympia alloy. The specimens were embedded, sectioned, and polished. Castability was analyzed by measuring the width of the cast meniscus of the margins. The margin widths of the flared and the straight sprue attachment groups were significantly less than the abrupt or gradual constriction attachment group ( p < 0.05). Photomicrographs revealed discernible differences in the relative quantity and location of porosity in the sprue-coping junctions. The straight and flared sprue attachment groups were less porous than the abrupt or gradual constriction groups (p < 0.01). Flared and straight sprue attachments optimized castability and minimized porosity.

Original languageEnglish (US)
Pages (from-to)418-424
Number of pages7
JournalThe Journal of Prosthetic Dentistry
Issue number4
StatePublished - Apr 1989
Externally publishedYes

ASJC Scopus subject areas

  • Oral Surgery


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