Study on the surface of resins that burn without residues in the lost-wax procedure.
BACKGROUND
When compared with waxes and prefabricated components made of dental alloys, processing resins is difficult and often results in a less accurate fit. The exact linear dimension is hard to realize, as the materials required for a dental casting are adjusted to dental waxes, and usually there are no special processing instructions for these resins.


OBJECTIVE
The surface structure of 16 residue-free burning resins was determined to find which could enlarge the range of application for waxes in the dental casting technique.


METHODS
A total of 480 specimens (30 castings for each of 16 resins) were marked with an individually cut pyramid, which left an impression in the resin. This was distinctly visible in the metal after casting in "the lost form." The surfaces of these 480 specimens were measured in three dimensions with a positioning aid "before casting in resin" and "after casting in metal" by the Perthometer micrometer. All specimens were treated identically by the lost-wax process by using the rotation symmetry of the muffle. The differences in the surface data before casting in resin and after casting in metal characterize the quality of the particular resin.


RESULTS
Surface roughness differed between the 16 resins in the range of micrometer.


CONCLUSIONS
With the dental casting technique, it is recommended that some resins replace waxes or wax-resin compositions.
Krane
M
M
Department of Prosthodontics, Center and School of Dentistry, University of Göttingen, Germany.
Patyk
A
A
Kobes
L W
LW
D003722:Dental Alloys / Q000737:chemistry; D003734:Dental Casting Investment / Q000737:chemistry; D003735:Dental Casting Technique; D006358:Hot Temperature; D008422:Materials Testing; D008768:Methylmethacrylates / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011137:Polystyrenes / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry*; D012399:Rotation; D013499:Surface Properties; D014885:Waxes / Q000737:chemistry
D003722:Dental Alloys; D003734:Dental Casting Investment; D008768:Methylmethacrylates; D011108:Polymers; D011137:Polystyrenes; D012117:Resins, Synthetic; D014885:Waxes; C068061:Palavit G; C017902:lexan; D019904:Polymethyl Methacrylate; C010102:delrin