journal club

1. PREPARED BY:-
DR. CHANDRA RAJPUT
GUIDED BY:-
DR. DARSHNA SHAH
DR. KEVAL SHAH
DR. CHIRAG CHAUHAN
DR. PARAS DOSHI

2.  An impression in complete dentures is the first
step in the fabrication of the complete denture
prosthesis. Various techniques are advocated for
taking the impression. Among them the most
accepted is selective pressure technique
proposed by Carl O Boucher. It can be achieved
either by scraping of the primary impression in
selected areas or by fabrication of custom tray
with a proper spacer design and escape holes.
Ref. Boucher CO. J Prosthet Dent 1951;1:472-91

3.  ROY MAC GREGOR DESIGN: He
recommends placement of a sheet of metal foil
in the region of incisive papila and midpalatine
raphae. He also says that the other areas that
may require relief are maxillary rugae, areas of
mucosal damage, buccal surface of the
prominent tuberosities .Finally he concludes
that the relief should not be used routinely in
the denture.
Ref : Mac Gregor Roy , Fenn, Liddelow and Gimson’s 3rd
ed. 1994. p.43-77

5.  2.NEILL DESIGN:
 He recommends adaptation of 0.9mm casting wax all
over except PPS area.
Ref: Neill & Nairn 3rd
ed. 1990. p.22-6.
 3.BOUCHER DESIGN:
 He recommends placement of 1 mm base plate wax on
the cast except posterior palatal seal area. He mentions
that this PPS area will act as guiding stop to position
tray properly during that impression procedure. He
also mentions about the placement of escape holes with
number 6 round bur in the palate.
Ref: Zarb & Bolender 11 ed. 1999. p.312-23.

7.  4. MORROW AND RUDD
DESIGN:
 He recommends to block out undercut areas
with wax and than adapt a full wax spacer 2
mm short of the resin special tray all over.
Then he recommends placement of 3 tissue
stops(4-4 mm) equidistant from each other.
Ref: Morrow & rudd Vol-1. 2nd
ed. 1986. p.26-56.

9.  5.SHARRY DESIGN:
 He recommends adaptation of layer of baseplate
wax over the whole area outlined for tray(even in
PPS area). He recommends placement of 4 tissue
stops(2 mm in width located in molar and cuspid
region which should extend from palatal aspect of
the ridge to the mucobuccal fold) and 1 vent hole
in the incisive papilla region before making the
final impression with the metallic oxide
impression material.
Ref: Sharry JJ. 3rd
ed. 1974, p. 191-210.

11.  6.BERNARD DESIGN:
 He recommends a layer of pink baseplate
wax(about 2 mm thick) attached to the area of
cast that usually have the areas of the softer
tissues; he recommends placement of wax
spacer all around, except the posterior part of
palate which according to him are at right
angles to the occlusal forces.
Ref: Bernard L. 1984 , p. 71-90.

13.  7. HEARTWELL DESIGN
 He mentions two techniques for achieving selective
pressure for maxillary impressions. In the first
technique he makes the primary impression with the
impression compound with non perforated stock tray,
the borders are refined, later space is provided in
selected areas by scraping of the impression
compound. In the second technique, he recommends
fabrication of custom tray (but did not mention about
the wax spacer). Border molding is done with low
fusing compound. He recommends placement 5 relief
holes on the palatal region, (3 in rugae area and 2 in
glandular region) before making the secondary
impression with ZOE paste.
Ref: Rahn & Heartwell 5th
ed. 2002 , p.221-47.

14.  8. SHELDON DESIGN:
 He describe 2 technique. In the first technique the primary
impression is made with low fusing modeling compound.
The borders are refined with green stick compound. Once
the operator is satisfied with retention, selective relief is
accomplished by scraping in the region of incisive papilla,
rugae and mid palatal areas. In the 2nd
technique he describe
of making a alginate primary impression. A primary cast is
pour. After analysis of cast contour, under cuts are blocked
out. Later he recommends placement of spacer or pressure
control (but did not describe about the wax spacer design).
Border molding is done with green stick compound before
making the secondary impression with ZOE paste.
Ref: Sheldon W. 2nd
ed. 1996. p. 88-106.

15.  9.HALPERIN DESIGN:
 He recommends the `philosophy of the custom
impression tray with peripheral relief’. According
to his philosophy the slopes of the ridges are
considered to be the primary stress bearing areas
and therefore these areas are functionally loaded
with compound during the making of the final
impression. Moreover he says that there is no need
to make awash secondary impression as he
considers the tray surface and the border-moulded
areas as the final impression surface.
Ref: Halperin, Graser, Rogoff, plekevich. 1988. p. 43-51.

16.  Certain amount of space is always necessary
for the impression material as the tissue would
be compressed to a certain extent during the
primary impression. The use of wax spacer is
more reliable because of the accuracy with
which we can achieve variable thickness of
impression material and thereby achieve
variable compression of tissue at different
areas.