english version(pg40to78) - Pr. François Duret

F Duret and Coll. Principes de fonctionnement et applications techniques de l’empreinte optique dans l’exercice de cabinet
(traduction Anglaise)
Page 103
[Fig 39: comparison of manufacturing of a micro-drill and the
sculpture of crowns]
MATERIALS
The realisation of a prosthetic piece necessarily needs successive
mouldings and in the most majority of cases, lost wax process. We
will not mention the multiple “inevitable” errors inherent to the
manufacturing process, and focus on the problem of the dental
biomaterial as it exists currently, for conjoined prosthesis (Fig 40 and
41).
In the majority of cases, we use:
- casting metals, covered or not in ceramics or compound resins
- and in a future we hope to be close, amorphous casting glass and
“ceramised” later by thermal treatment. But in every case the
material will be casted or moulded in our laboratories with
limited performances if we compare them to those of the same
type from industrial laboratories. This manufacturing mode of
our prosthetic pieces presents in our opinion 2 major
disadvantages:
1) it rejects any material which won’t cast or be moulded with the
technological means of our laboratories. Thus are rejected a
number of biocompatible substances for the simple and unique
reason that our “home-made” technology doesn’t let us work on
them.
2) It requires:
- heavier and heavier technical material
- more and more qualified labor
- a manufacturing time that always increases with new clinical
needs which are legitimate.
Les Cahiers de Prothèse (50) pp 73 – 110, 1985