1. An analysis of the development of complete denture
impression techniques
Ira D. Zinner, D. D. S., M. S.D. ,* and Herbert Sherman, D. D. S.**
New York University, New York, N.Y.
T
1mpression making for complete denture prostho-
dontics has matured from the art of carving wooden
or ivory blocks that accommodated the intraoral
contours to the more sophisticated methods in use
today. The various stages are all significant.
A historical review demonstrates the advances in
techniques which are due to a more thorough
knowledge of tissues, their behavior, and their reac-
tion to manipulation.
While materials used often influenced techniques
in the past, material-dictated techniques have long
been criticized as have techniques based upon empir-
icism.
Most materials can be manipulated in almost any
way to make impressions. Some materials cannot be
used because of physical characteristics which affect
tissue reaction,
Advances in the theory underlying impression
techniques sometimes promote the need for new
impression materials. Sometimes the development of
a new material permits an accommodation to an
improved technique. Despite advances, older tech-
niques are continually being used, even though new
procedures and theories have been developed.
This study documents the frequency and historical
development of knowledge associated with scientific
advancement from 1845 to 1964 in biology, psychol-
ogy, material science, and the clinical sciences as
they related to impression procedures in complete
prosthodontics.
LITERATURE REVIEW
A total of 145 books were reviewed from those
listed under “Prosthetic Books Published” in the
Submitted in partial fulfillment of the requirements for the
M.S.D. degree.
*Former Associate Clinical Professor, Department of Removable
Prosthodontics.
**Associate Professor, Department of Removable Prosthodon-
tics.
242 SEPTEMBER 1981 VOLUME 46 NUMBER 3
Index of Dental Literature, published annually from
1845-1964. In 77 of these books, there were no
references to complete denture impression making.
The remaining 68 books were arbitrarily divided by
eras for a historical analysis of their relevant con-
tent :
1. Prior to 1900-12 books
2. 1900-1929-22 books
3. 1930-1949-18 books
4. 1950-1964-16 books
Only textbooks were reviewed and analyzed for
this study, since texts are reference books used by the
profession. Publications other than textbooks, such
as dental journals, were not included. The authors
assume that if any important technique or theory of
impression making is published in a dental journal,
it is eventually published in a textbook. Conversely,
it is assumed that impression making techniques or
theories that do not contribute or add to existing
knowledge do not generally appear in textbooks.
When a textbook had a series of editions or revisions,
only the latest edition was reviewed.
HISTORY OF COMPLETE DENTURE
IMPRESSION MAKING
Prior to the 1600s complete denture replacements
were not made, due to a lack of understanding of
retention. Replacements were made only when pos-
terior abutment teeth remained in the mouth. Arti-
ficial teeth for earlier civilizations were formed of
ivory and wood, while a few were mounted on gold
plate. Ancient Egyptians, circa 300 BC, wired artifi-
cial anterior teeth in the mouth for esthetics. Teeth
and bones of cattle as well as ivory were used in
making prostheses until the 18th century.
The primitive methods of the early 18th century
were relatively uncomplicated and used simple
materials. In 1711, Matthias Gottfried Purman
recorded the use of wax. In 1928, Pierre Fauchard
made dentures by measuring the mouth with com-
@X2-3913/81/090242 + 08$00.80/O 0 1981 The C. V. Mosby Co.
2. DEVELOPMENT OF COMPLETE DENTURE IMPRESSION TECHNIQUES
Impression
Procedures
u. 0 dl ,-dl
Comprrsrive oprn Closed Immodiatp
Yi Impretrionr Mouth Mouth oenturer
5
;--II 4
i
Era II -1900-1929
Era In-1930-1944
Mucoltctic Relief hole
Impressions in tray
Fig. 1. Index of frequency for impression procedures.
From left to right, first bar graph represents era I-1545 to
1899; era II-1900 to 1929; era III-1930 to 1944; and era
IV-1950 to 1964.
passes and cutting bone into an approximate shape
for the space to be filled.
In 1736, Phillip Pfaff of Germany used plaster
casts and described a procedure for recording maxil-
lomandibular relations. The impressions were made
in wax sections of half of the mouth at a time.
Plaster of Paris was first used as an impression
material in 1844. Credit for its introduction is
divided among three dentists-Westcott, Dwinelle,
and Dunning. Gutta percha was first introduced in
1848. It was placed in boiling water, kneaded, and
molded in the same way as wax and then immedi-
ately inserted firmly into the mouth.’ It is of interest
to note that some materials presently used were
introduced 130 to 250 years ago.
1845-1899
Several basic principles of complete denture
impression making were introduced in the middle of
the 19th century. The concepts of atmospheric
pressure, maximum extension of the denture-bearing
area, equal distribution of pressure, and adaptation
of the denture-bearing tissues were stressed.‘.” There
was an evolution of impression materials which
included some types of modeling compound.‘. ’
Many changes in impression making became evi-
dent during this era. A single impression, formerly
deemed sufficient, advanced to a method using a
preliminary impression of gutta percha, beeswax, or
modeling compound. This was followed by a second-
ary wash impression made of plaster within the
preliminary impression.“, ’ Retention, stability, and
comfort of the complete denture were described as
functions of anatomic considerations in some of the
texts in the latter part of this era.
Most authors were concerned with stability and
retention. There was little discussion in the literature
Mandibular Cheek
Movement Movement
Border
Tissue
Movemeni
Other Oral
Tissue
Movement
1
Lip
Movement
Oral Muscle and
Tissue Movement
Al dl
Polatal Pwiphersl
Movrment Muscle
Mcvamrn t
Fig. 2. Index of frequency for muscle and tissue move-
ment.
regarding tissue behavior and the effects of impres-
sion making on tissue.
All the impression methods at this time were of an
open mouth variety. Closed mouth impression proce-
dures were not introduced until well after 1900.
Border molding (referred to then as “muscle trim-
ming”) varied from pulling the cheeks downward to
having the patient himself move the cheeks in a
downward direction.“. (i
IMPRESSION TRAYS
Many types of impression trays were developed
during these first formative years. All impression
trays (or as they were called “impression cups”) were
of metal which was used for durability, strength,
rigidity, and lightness. The most commonly used was
Britannia metal, but similar alloys or sheet alumi-
num permitted trimming and bending to adapt the
tray and possessed sufficient rigidity to maintain its
shape even under considerable pressure. Other met-
als used were lead, copper, tin, silver, German silver,
and pewter. Th e impression trays had round or
square troughs depending on the material used.
Some had high flanges, while others had short. One
set of impression trays had double flanges, the upper
flange being used to retract the &eeks, lips, and
tongue and to prevent them from being caught in
the impression, while the lower flange brought the
impression material into contact with ridge and
contiguous tissue. Another type of tray had an open
trough, through which impression plaster was
poured so that it would flow throughout the denture-
bearing area and into all crevices of the remaining
teeth. Nonmetal trays developed during this period
were constructed mostly of gutta percha or vulcanite.
THE JOURNAL OF PROSTHETIC DENTISTRY 243
3. ZINNER AND SHERMAN
1.
6
5I
4-
3-
2-
I-
o-
Pressure
Phenomena
LkD -
Mucostatic Equalization Mosticatory Atmospheric
Ion - pressure) of Pressure Pressure Pressure
Adhesion
n
Surface
Areo
Covoroge
Retention Stability Adhesion
and
Cohesion
?
Fig. 3. Index of frequency for pressure phenomena.
-c 2l- n
DMtur*Extension
Anatomic Region
Management
- __c_
Dirplacrablr Fooiol
Ridgoa Contoura
Fig. 4. Index of frequency for anatomic concepts.
These nonmetal trays were used to make a final wash
impression with plaster after a preliminary impres-
sion had been made.‘-”
1900-1929
During thte years from 1900 to 1929, there were
many innovations in complete denture impression
procedures. Reference is still made to the classic
textbooks and authors from this era.
A concentrated effort was directed toward accura-
cy. Most impressions made during this era, as in the
preceding one, were of the compressive type. Howev-
er, some authors”, i advocated a release or escape
vent within the final impression tray to prevent the
buildup of excessive pressures. The closed mouth
impression Technique was also introduced.* Rebase
impressions were mentioned as impressions of a
secondary type using a free flowing material which
compensated for changes in the tissues. Such final
impressions were made within an existing denture or
baseplate.
Greater attempts were made to understand the
need for proper denture extension. Methods of
border molding to capture the anatomy of the tissues
contiguous to denture borders were introduced. The
unique problem of the displaceable maxillary ridge
was recognized. Two techniques were developed for
handling the “flabby ridge.” The first!’ involved a
compressive type of compound impression which
displaced the “flabby ridge” palatally. The rationale
was that as the patient functioned the denture would
move forward, returning the tissues to their normal
state. The second method” advocated that hypertro-
phied tissue should be captured in its passive form,
and a technique was developed accordingly.
A number of author? “I described a sucking and
swallowing action for border molding in addition to
other methods.‘-” Moving the peripheral muscula-
ture in the direction of the attachments, resulting in
occlusion of the mucobuccal fold both in height and
width by the denture borders, was one such method.
This is considered biologically sound and within the
limits of muscle function. Another method” pro-
posed was that of manipulating the musculature
against the direction of the muscle fibers,
which resulted in foreshortening the final denture
borders.
The concept, location, and placement of the
posterior palatal seal for the complete maxillary
denture were explained on an anatomic as well as a
mechnical basis. Some authors”. !’ recommended
extending the posterior palatal seal ‘/4 inch beyond
the vibrating line when the upper anterior tissue was
displaceable. One author” advocated ending the
244 SEPTEMBER 1981 VOLUME 46 NUMBER 3
4. DEVELOPMENT OF COMPLETE DENTURE IMPRESSION TECHNIQUES
O-
7-
6-
z J-
= 4-
s 3-
2-0). l-
LLo-
5
I: 30 2-
= I-
Skeletal -
Non specific
dlPOlok Tubworitirr Undrrcuir
Skeletal -
Specific
vig? -ii&F -4s -is
t Rid99 Notch Palotinur
Fig. 5. Index of frequency for bony regions.
posterior denture border at the foveae palatini. Most
texts, however, report the termination of the posteri-
or palatal seal at the vibrating line of the pal-
ate,‘. 7-R.11 Acceptance of this concept continues
today.
Generally, all authors recognized the need for
more accurate denture impressions.
The most important biologic concept introduced
in this era was an awareness of the oral and perioral
muscles as they related to the borders of the complete
denture impression. For the first time there were
references to movement of border tissues and the
mandible during impression making. Authors
stressed the necessity to determine borders in their
most favorable state and further developed closed
mouth impression techniques. There was an attempt
to relate border and denture-bearing tissues to den-
ture function. An increasing number of authors
moved from the purely mechanical technique of
denture construction to the biologic or biomechani-
cal concept.
During this second era, no new materials for
impression making were introduced, only variants of
existing materials. Modeling compound was used as
the material of choice for preliminary impressions.
The final impression was made in plaster either
within the preliminary impression or within a cus-
tom tray made of metal, vulcanite, or baseplate.
There was increased interest regarding properties
and behavior of the materials and their relationship
to selected techniques.
It was during this era that the concept of esthetics’
in impression making was introduced.
1930-1940
This era recognized the anatomy of the denture-
bearing areas, and of muscle physiology as related to
impression procedures.
dill
Tongue MUSCI~Attachmmts
Muscles -
Non-specific
r-7
dCheeks
5 (Frrno)
Muscles -
SDecif ic
Mylohyoid Buccinotor
r-
MWCIO
Morlctsr
MUSCIO
Superwx
Mu~cla Constrictor
Muscle
Fig. 6. Index of frequency for muscles.
G Chemoplar t ic-7
Zinc Osidr
C Matrrlolr
Polymer-- Type---
Materials
3-
4-
3-
2-
Thermoplaetic--
MoterloC
Colloidal
Materials
I1
-41Alginotr Hydrocolloid
Trays--
Fig. 7. Index of frequency on thermoplastic materials.
There was greater knowledge of muscle anatomy
and muscle physiology and the effects of the muscu-
lature upon dentures. This is evident in descriptions
of border molding of dentures. Many authors’3-“1
advocated manipulation in border molding by mov-
ing the peripheral musculature in the direction of its
fibers rather than against this direction. The need to
completely cover the retromolar pad for maximum
stability was stressed.‘J-“’
Additionally, there was emphasis on immediate
denture impression techniques.‘“. 2*-2y‘the only prior
reference regarding immediate denture impressions
THE JOURNAL OF PROSTHETIC DENTISTRY 245
5. ZINNER AND SHERMAN
and Atrophy Resorption Trauma, etc.
Strotiticd
Squamous
Epithelium
Connective
Tissue
Histologic
References
Fig. 8. Index of frequency for pathology and histology.
was Litch (1887). Immediate dentures were used not
only for esthetics but for maintenance of muscle
tonicity, in the perioral musculature.
Several new impression materials were intro-
duced: reversible hydrocolloids, zinc oxide-eugenol,
and zinc oxide and oil of cloves.” Modeling com-
pound and plaster still remained the two major
impression materials used in both preliminary and
final impression procedures. There was a greater
understanding of the properties and behavior of
modeling compound and plaster,“. ‘li some under-
standing of the properties of the zinc oxide-oil of
cloves impression paste,” and very little understand-
ing of the properties of the hydrocolloids.“’
In the 193Os, most techniques stressed the use of
plaster for fina’l impression procedures. In addition,
there was a trend away from making the final
impression ti<thin the preliminary compound
impression. Construction of an individual tray from
a cast of the preliminary impression was emphasized,
and the final impression was made in this individual
or customized ‘tray. The value of mandibular posture
records and their relationship to the impression
procedure was recognized. A few authors” advo-
cated using a closed mouth impression procedure at
the correct vertical dimension of occlusion in centric
relation.
There was a trend against displacement of the
hypertrophied maxillary anterior tissue palatally.
Emphasis was placed more upon making impressions
of displaceable tissue in its passive state.‘“. “. ”
The introduction of a new impression procedure
and the concept of mucostatics occurred in this era.
The idea was to achieve the best possible adaptation
of impression material to tissues and to capture the
tissues in their passive undistorted form.
r Coughing
LO-
‘;;
::
m
= OS-
d
Patient
Comtor t
Vomiting. Smd I,
Nall**a Taste
1 Phvsiolog&
References
Psvcholoaic.
References
Patient Desire, Hobits.
Instruction Fear, etc.
Fig. 9. The index of frequency on physiology and psy-
chology.
1950-1964
In the period from 1950 to 1964, there was
increased emphasis on those biologic factors that
affect complete denture impression making. Clinical
procedures advocated earlier were described with
greater insight into the anatomy and physiology of
the oral and perioral tissues.
Awareness of muscle movement and relationship
to complete denture impressions was evident. Most
authorSlX, “3. 24 advocated the use of one or more
escape vents in the individually constructed impres-
sion tray prior to making the secondary or final
impression. There was greater emphasis on flanges,
border molding, and denture extensions. An increase
of interest in the posterior palatal seal was obvious as
was emphasis on the management of the displace-
able ridge. There was also more attention given to
the relationship of esthetics to complete denture
impression techniques.
Despite these advances, modeling compound
remained the material of choice for making prelimi-
nary impressions. Secondary impressions were
described as being made with zinc oxide-eugenol
paste or plaster.
Other types of impression materiaWJ such as
rubber base (mercaptan or thiokol) and silicones
were introduced. More authors’“, “‘I. ?“. “’ advocated
the use of an individually constructed nonmetallic
tray to be used for making the final impression wash,
rather than making it inside the preliminary com-
pound impression.
There was a greater understanding of the proper-
ties of the various materials used in complete denture
246 SEPTEMBER 1981 VOLUME 46 NUMBER 3
7. impressions, including plaster, modeling compound,
and the materials used for impression trays. The
properties of zinc oxide-eugenol impression paste
and how the pa!jte related to tissue were better
understood than when first introduced.
despite the introduction of new materials such as
zinc oxide-eugenol paste, alginates, reversible hydro-
colloids, thiokol rubbers, and silicones (Fig. 7).
SUMMARY
There were very few references to pathology,
histalogy, and behavioral aspects of impression mak-
ing and no trend was observed over the four eras
(Figs. 8 and 9).
Sixty-eight textbooks published in English since
1845 have contained references to impression mak-
ing. References in these volumes to biologic, psycho-
logic, behavioral and material science, and to clinical
procedures were recorded. These notations were then
tabulated into four eras for statistical analysis.
The history of impression making shows that most
of the significant advances occurred before 1930.
Basic principles of pressure, maximum extension of
the denture base over the denture-bearing area, and
equal distribution of pressure were first introduced
in the era 1845 to 1899.
There were a total of 9,005 references in the
various categories. For each classification an index of
frequency was calculated (Figs. 1 to 9). The index of
frequency is the number of times an item was
recorded in an era divided by the number of books in
that era. For exa.mple, under the category of pressure
phenomena (Fig. 3), a reference to “equalization of
pressure” in the 1900 to 1929 era was recorded 33
times. There were a total of 22 books published in
this era. Therefore the index of frequency for this
item in the second era is 33 + 22 or I .5 (Fig. 3). The
index of frequency gives a measure of the interest in
impression making (Table I).
The most significant advances in the art were
developed in the second era, 1900 to 1929. Advances
in the accuracy of impression techniques and an
increase in the methods of border molding and
obtaining a posterior palatal seal were among the
major innovations in this era.
The era from 1930 to 1949 saw great advances in
the knowledge of the anatomy of the oral and
perioral tissues as they affect impression making.
The use of immediate denture techniques and the
introduction of several new materials such as zinc
oxide-eugenol paste and the hydrocolloids were also
noted.
An increase in the index of frequency for compres-
sive impressions, border molding, and denture exten-
sion was recorded over four eras. References to closed
mouth impressions showed a smaller increase. No
increase in references to displaceable ridges and
facial contours was seen over the four eras, and a
decrease was noted in the index of frequency for
rebase impressions (Fig. 1).
The fourth era saw progress in the biologic aspects
of denture impression making. There was an appre-
ciation of the rationale for border molding and an
awareness of the muscles and how they relate to
complete denture impression techniques.
The index of frequency increased greatly in vari-
ous categories of oral muscle and tissue movements
over the four eras as authors became more sophisti-
cated in the biologic concepts of impression making
(Fig. 2). Simil,arly there were large increases in the
index of frequency for many subcategories of physi-
cal phenomena-surface area coverage, retention,
denture extension, and soft tissue displacement (Fig.
3). On the orher hand, references to atmospheric
pressure, peripheral seal, posterior palatal displace-
ment, and border tissue adaptation showed little or
no trends over the four periods of time.
The importance of an in-depth review of impres-
sion making lies in the assessment of the historical
value of all factors. The categorization for these
factors into their respective physical, biologic, and
behavioral areas can show their relativity to the time
in which they were discussed and taught as well as to
their assigned importance.
REFERENCES
Index of frequency for references to anatomic
areas remained fairly constant for nonspecific sites
but showed an increase in references to specific
bones, muscles, and oral spaces (Figs. 4 to 6).
References to modeling compound and plaster
showed large increases, especially in the later era,
1.
2.
3.
4.
5.
Prothero, J. H.: Prosthetic Dentistry. Chicago, 1916, Medi-
co-Dental Publishing Co.; ed 3, London, 1921, Charles Ash
and Sons, chaps 5-7, and 25.
Harris, C. A.: The Principles and Practice of Dental Surgery,
ed 2, part 6. Philadelphia, 1845, Lindsay & Blakiston,
chaps 2 and 4.
White, J. W.: Taking Impressions of the Mouth, ed 2.
Philadelphia, 1895, S. S. White Dental Mfg. Co.
Essig, C. J.: The American Textbook of Prosthetic Dentistry.
Philadelphia, 1896, Henry Kimpton, chap 6; ed 2, New
York, 1900, Lea Brothers and Co.
Richardson, J. A.: Practical Treatise on Mechanical Dentist-
ry. Philadelphia, 1860, Lindsay & Blakiston, chap 2; ed 2,
1868; ed 3, St. Louis, 1880, Hildreth Printing Co.; ed 4,
248 SEPTEMBER 1981 VOLUME 46 NUMBER 3
ZINNER AND SHERMAN
8. DEVELOPMENT OF COMPLETE DENTURE IMPRESSION TECHNIQUES
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
London, 1886, J. & A. Churchill Ltd.; ed 6, 1893, revised
and enlarged by George W. Warren; ed 7, London, 1903,
J. & A. Churchill Ltd., chaps 13 and 14.
Turner, C. R.: The American Textbook of Prosthetic Den-
tistv. Philadelphia, Lea Brothers and Co.; ed 2, London.
Henry Kimpton; ed 3, 1907, revised and rewritten; ed 4,
Glasgow, 1913; ed 5, Turner, C. R., and Anthony, L. P.,
editors, London, 1928, Henry Kimpton; ed 6, Philadelphia,
1932. Lea & Febiger, chaps 3 and 14.
Campbell, D. D.: Full Denture Prosthesis. St. Louis. 1924,
The C. V. Mosby Co., chaps 1, 4, 7, and 16.
Lieberthal, R. H.: Advanced Impression Taking, New York,
1919, Professional Publishing Co.. chaps 1 and 2.
Greene, J. W.: Greene Brothers’ Clinical Course in Dental
Prosthesis. In three printed lectures: 1910, 1914, 1916.
Detroit, Detroit Dental Mfg. Co., lectures 1 and 2.
Clapp, G. W.: The Mechanical Side of Anatomical Articu-
lation. New York, 1912. Dental Digest Press.
Wilson, G. H.: A Manual of Dental Prosthesis. New York,
1917, Lea and Febiger; ed 2, London, 1914, Henry Kimpton,
chap 2; ed 3. 1916, ed 4, 1920.
Bunce, E. W.. The Bunce-Kanouse Full Denture Technic.
Chicago, 1929, Coe Laboratories, Inc., Chapters 3-5.
Nichols, I. G.: Prosthetic Dentistry. An Encyclopedia of Full
and Partial Denture Prosthesis. St. Louis, 1930, The C. V.
Mosby Co., chaps 4, 14, and 30.
Neil, E.: Full Denture Practice. Nashville, 1932, Marshall &
Bruce Co., chaps 3-5.
Fish, E. W.: Principles of Full Denture Prosthesis. London,
1933, John Bale Sons & Danielsson; ed 3, London, 1937,
John Bale & Sons and Curnow; ed 4, London, 1948, Stapler
Press; ed 5, London, 1952, Stapler Press; ed 6 (Appendexes
contributed by Ernest Matthews), London 1954. Stapler
Press, chap 4, Appendexes 1, 2, and 4.
16.
17.
18.
19.
20.
21.
22.
23.
24.
Litch, W. F.: The American System of Dentistry, vol
2-Operative and Prosthetic Dentistry. Philadelphia, 1887,
Lea Brothers & Co., part II, chap 1.
Doxtater, L. W.: Full and Partial Denture Prosthesis. Brook-
lyn, 1936, Dental Items of Interest Publishing Co.; chaps 2,
13, 16, and 21-23.
Craddock, F. W.: Prosthetic Dentistry: A Clinical Outline,
ed 2. London, 1951, Henry Kimpton, 1945, chapter 3.
Schlosser, R. 0.: Complete Denture .Prosthesis, ed 2. Phila-
delphia, 1939, W. B. Saunders Co.; ed 2, 1946; ed 3, 1953: ed
4, Gehl, D. J. and Dresen, 0. M., editors, 1958, chapters 6,
S-11, 21, and 22.
Swenson, M. G.: Complete Dentures St. Louis, 1940, The
C. V. Mosby Co.; ed 2, 1947; ed 3, 1953; ed 4 (in
collaboration with Stout, C. J.), 1959; ed 5, 1964, Boucher,
C. O., editor, chaps 3, 13, 19, 31-33, and appendix.
Sears, V. H.: Prosthetic Papers. Minneapolis, 1936, Dental
Library, Bureau of Engraving, Inc.
Boyle, H. H.: The Principles and Pracice of Applied Dental
Aesthetics. London, 1936, Henry Kimpton, chaps 3 and
13.
Landa, J. S.: Practical Full Denture Prosthesis. London,
1947; Brooklyn, 1954, Dental Items of Interest Publishing
Co.; London, 1958, Henry Kimpton, chaps 8-10, 31, and
32.
Lammie, G. A.: Full Dentures. Oxford, 1956, Blackwell,
chaps 4 and 5.
Reprint requeststo:
DR. IRA D. ZINNER
115 E. 61s~ ST.
NEW YORK, NY 10021
THE JOURNAL OF PROSTHETIC DENTISTRY 249
