Biological considerations of maxillary impressions/ courses for dentistry

BIOLOGICAL CONSIDERATIONS OF
MAXILLARY
IMPRESSIONS
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

CONTENTS-
 Introduction
 Definition
 Supporting structures
1. Bone
2.Mucous membrane
 Peripheral or limiting structures

 Anatomy of limiting structures in maxillary
region
 Anatomy of supporting structures in
maxillary region
 Conclusion
 References

INTRODUCTION-
If dentures and their supporting tissues are to coexist for a
reasonable length of time, the prosthodontist must fully understand
the macroscopic and microscopic anatomy of edentulous mouth of
the
patient.

 Anatomic landmark-
“ a recognizable anatomic structure
used as a point of reference.”
GPT-8
 In both maxilla and mandible anatomic
landmarks has been divided in-
-supporting structures
-peripheral or limiting structures

SUPPORTING STRUCTURES
 Def-
“Those areas of maxillary and mandibular
edentulous ridges that are considered best
suited to carry the forces of mastication when
dentures are in function.” (GPT-8)

 Maxillary and mandibular dentures transfer
occlusal loads to these so called
supporting structures .
 The ultimate support for a denture is
provided by the underlying bone which is
covered by mucous membrane. Support is
provided by maxillae and palatine bone in
case of maxillary denture. For mandibular
denture support is provided by mandible.

 In both maxilla and mandible type of bone
and mucous membrane overlying it, differs
from area to area.
 Each type of tissue found in oral cavity has
its own characteristic ability to resist
external forces depending on its nature
and histological makeup i.e type of bone
and mucous membrane.
 Stress bearing and relief areas

Hard tissues-
 The requirement of ideal support is the
presence of tissues that are relatively
resistant to remodeling and resorptive
changes.

 2 types of bones are seen
-compact or cortical bone
-cancellous or trabecular bone

DIFFERENCE IN RIDGE RESORPTION IN
COMPACT AND CANCELLOUS BONE-
 It has been suggested that bone resorption
at any site is a chemotactic phenomenon,
that is it is initiated by release of some
soluble factors that attract circulating
monocytes to the target site. Osteoclasts,
the cells responsible for bone resorption are
nothing but modified monocytes.
 Degree of mineralization is less in
cancellous bone, so effects of resorption
are more pronounced in cancellous bone.

Oral Mucous Membrane -
The bone of upper and lower edentulous
jaws, and the oral cavity is lined with a soft
tissue that is known as ‘mucous membrane’.
Denture bases rest on the mucous
membrane, which serve as a cushion between
denture base and supporting bone.
The mucous membrane composed of :-
(i) Mucosa
(ii) Sub mucosa

1) Mucosa: -
Mucosa is formed by stratified
squamous epithelium cells.
There is subjacent narrow layer of
connecting tissue to the mucosa, known
as lamina propria.

2) Sub mucosa: -
Sub mucosa is formed by connective tissue.
Connective tissue varies in character from
dense to loose alveolar tissue and also varies
considerably in thickness.
It may contain glandular, fat or muscle cells.
Submucosa transmit the blood and nerve
supply to the mucosa.
Sub mucosa attaches mucosa to the
periosteal covering of the bone.

 Some parts of the masticatory
mucosa are without a distinct submucous
layer, yet dense connective tissue of the
lamina propria firmly binds the mucosa to
underlying periosteum. Although not as
effective in providing resiliency, this
connective tissue layer serves as a
protective base for the mucosa.

Classification of oral mucosa-
Depending on its location in mouth, oral
mucosa classified into three categories –
Oral mucous
membrane
Masticatory Lining Specialized

Limiting structures-
 The functional anatomy of mouth determines the
extent of the basal surface of denture.
 The denture base should include the maximum
surface possible within the limits of the health and
function of the tissues it covers and contacts i.e it
should cover all the available basal seat tissues
without interfering in action of any of the structures
that contact or surround it.
 The anatomy in consideration is anatomy in
function rather than descriptive anatomy.

 Term ‘Border area’ refers to the mucosal surface
area which contacts the denture borders and
surrounds the spaces which are occupied by
denture flanges.
 Border molding procedures are used to record
limiting structures properly. There are 2 main
objectives of border molding in recording the
limiting structures-
1. to establish correct flange length and
border thickness
2. to achieve retention through border seal.

LIMITING STRUCTURES IN MAXILLARY
REGION

 Labial frenum
 Labial vestibule
 Buccal frenum
 Buccal vestibule
 Hamular notch
 Vibrating lines
 Fovea palatinae

1. LABIAL FRENUM
 Term frenum or frenulum refers to a
connecting fold of mucous membrane
serving to support or retain a part.
 labial frenum, is a fold of mucous
membrane extends from the labial mucous
membrane reflection area to or towards
the slop or crest of residual ridge at the
median line.

 It divides the labial vestibule into
approximately equal but asymmetrical left
and right labial vestibule.
 It starts superiorly in a fan shape and
converges as it descends to its terminal
attachment on the labial side of the ridge.
 It contains no muscle and has no action of
its own.

 The action of the lip in
this area is mainly
vertical so the labial
notch in maxillary
denture must be just
wide and deep enough
to allow the frenum to
pass through it.
 The denture borders
should not only be cut
lower, but also have
less thickness adjacent
to labial notch.

House classified
frenal attachment in
3 classes-
 class1- high in
maxilla or low in
mandible with
respect to crest of
ridge.

 class 2- medium

 class 3- freni
encroach on
the crest of
the ridge and
may interfere
with denture
seal, might
require
surgical
correction.

Vertical incisive
pads-
 When lip is raised
and pulled
horizontally forward,
a pad of
submucosal soft
tissue in the shape
of vertical column is
sometimes
observed on each
side of maxillary
labial frenum, are
known as vertical
incisive pads.

 These are attachments of the superior
incisive muscles, which course up from
their attachments.
 The basal surface of labial flange of the
denture should be relieved to allow for
these attachments.

Anterior nasal spine-
 It is not a limiting structure under normal
circumstances, but in instances of severe
ridge resorption, the anterior labial border of
denture should be relieved to avoid
impingement upon the mucosa overlying the
anterior nasal spine, which frequently
becomes a prominent, knife edged, limiting
structure.

Labial vestibule
 The portion of the oral
cavity that is bounded
on one side by the
teeth , gingiva and
alveolar ridge (or
residual ridge) and on
the other by the lips
anterior to the buccal
frenum.
GPT-8
•The labial vestibule is divided into a left and right
labial vestibule by the labial frenum.

Three objectives which are apparent in
the labial vestibular region are-
1. The thickness of the labial flange of the final
impression must be developed according to the
amount of bone that has been lost from the
labial side of the ridge.
2. The labial flange of the impression must have
sufficient height to reach the reflecting mucous
membrane of the vestibular space, but should
not over extend it.
3. There must be no interference of the labial
flange with action of the lip in function.

 The main muscle of the
lip, which forms the outer
surface of the labial
vestibule, is the orbicularis
oris.
 It’s tone depends on
the support it receives from
the labial flange and the
position of the teeth.
 Because the fibers run
in a horizontal direction, the
orbicularis oris has only an
indirect effect on the extent
of an impression and hence
on the denture base.

BUCCAL FRENUM
 Buccal frenum is a
fold of mucous
membrane, extends
from the buccal
mucous membrane
reflection area to or
towards the slop or
crest of residual
ridge.
• The buccal frenum forms the dividing line between
the labial and buccal vestibules.

 It is sometimes
a single fold of
mucous
membrane,
sometimes
double, and in
some mouth,
broad and fan
shaped.

Three muscles are attached in this region
1. The levator anguli oris (caninus) muscle attaches
beneath the frenum and affects it’s position.
2. The buccinator pulls it backward.
3. Orbicularis oris pulls it forward.

 Because of muscle attachments, it
requires more clearance for its action( in
both horizontal and vertical direction) than
the labial frenum does.
 Inadequate provision for the buccal
frenum or excess thickness of the flange
distal to the buccal notch can cause
dislodgement of the denture when the
cheeks are moved posteriorly as in broad
smile.

 It records in the
impression as a
buccal notch
which is
properly
relieved and
molded.
• It should be cresentric in form, rather than ‘V’
shaped.

Buccal vestibule
 It is defined as “the portion of oral cavity
that is bounded on one side by the teeth,
gingiva and alveolar ridge (residual
alveolar ridge) and on the lateral side by
the cheek posterior to the buccal frenula”.
GPT-8

 The buccal
vestibule lies
opposite the
tuberosity
and extends
from the
buccal
frenum to the
hamular
notch.

The size of the buccal vestibule varies with
 contraction of the buccinator muscle,
 the position of the mandible, and
 the amount of bone lost from the maxilla.

 The extent of the buccal vestibule can be
deceiving because the coronoid process
obscures it when the mouth is opened
wide. Therefore it should be examined
with the mouth as nearly closed as
possible.
 This space usually is higher than any other
part of the border.

 The size and shape of the distal end of the
buccal flange of the denture must be
adjusted according to the ramus and the
coronoid process of the mandible.

 Coronomaxillary Space -
(J.Prosthet.Dent 1987:57; 186-190.
N.S.Arbree, A.A.Yurkstas, and J.H.Kronman.)
 Definition:- The coronomaxillary space is that
anatomic region that lies medial to the coronoid
process and lateral to the maxillary tuberosity.

 Terms used to identify the coronomaxillary
space,are :-
 1- Buccal space or vestibule,
2- Buccal pocket,
3- Tuberosity sulcus
4- Distobuccal angle of the vestibule,
5- Buccal sulcus,
6- Buccal pouch,
7- Buccal mucous membrane reflection
region,
8- Postmalar area,
9- Retrozygomatic space.

Clinical Implications:-
 To get the maximum retentive qualities of the
prosthesis, each patient should be evaluated for
variation in the coronomaxillary space size during
mandibular opening, as the size of the space is
primarily influenced by the action of the coronoid
process.

 In some
patients coronoid
process appears
to flare laterally at
its height. For
these patients
space often
remain same or
becomes wider
during opening of
the mouth.

 The coronoid
Process may be
relatively straight or
constricting medially .
For these patients
opening of the
mandible can result
in narrowing of the
space.

 If the space narrows
during opening, any
horizontal overextension
into the space would
result in denture base
contact and loss of
retention.
 In this region border
molding procedure
should include opening
and closing, together
with protrusion, and
lateral movements of
the jaw.

 If coronomaxillary
space broadens or
remains of same size on
opening, the functional
filling of this space with
the denture flange
becomes important.
border molding should
not be done with open
wide, protrude, or any
lateral movements.
•Here a gentle molding of the region is done by
pulling the cheek out, down and inwards.

Microscopic features of labial and
Buccal vestibule -
- The mucous membrane lining of vestibule is
relatively thin.
- The submucosal layer is thick and contains
large amount of loose areolar tissue and elastic fiber.
- The mucosa of the vestibular space is
classified as lining mucosa.
- Mucosa is devoid of keratinized layer and is
freely movable with the tissue to which it is attached
because of the elastic nature of the lamina propria.

Hamular notch
 Hamular notch is a
displaceable area,
about 2mm wide
between the
tuberosity of the
maxilla and the
hamular process of
the medial
pterygoid plate.
Also called as pterygomaxillary notch

Clinical Significance -
 This notch is used as a boundary of the posterior
border of the maxillary denture, back of the
tuberosity.
 The impression should not end on the tuberosity,
otherwise it will result in nonretentive denture
because peripheral seal is not possible in
nonresilient area of tuberosity.
 The tissue in the centre of the deep part of the
hamular notch, can be safely displaced by the
posterior palatal border of the denture to help in
achieving a seal in this region called as pterygo-
maxillary seal.

 The tip of the pterygoid hamulus is 2-3 mm
posteromedial to the distal limit of maxillary
residual ridge. However it may be located on the
line with crest of ridge or sometimes even lateral
to this line.
 This variation is significant in that it affects the
length and the direction of pterygomaxillary seal
so it becomes very important to determine the
location of hamulus by palpation.

 Pterygomaxillary
seal occupies
the entire width
of hamular
notch. The seal
begins at
pterygomaxillary
notch and
usually extends
5-7 mm
anteromedially.

 Also overextensions at the hamular
notches will not be tolerated because of
pressure on the pterygoid hamulus and
interference with the pterygomandibular
raphe.
 Special care should be taken in the
grossly resorbed alveolar ridge, where
hamular notch disappears and raphe
becomes more prominent.

 When the mouth is
opened wide, the
pterygomandibular
raphe is pulled
forward. If the denture
extends too far into
the hamular notch,
the mucous
membrane covering
the raphe will be
traumatized

PALATINE FOVEA REGION-
 The fovea palatinae are indentations
near the midline of the palate in posterior
region formed by coalescence of several
mucous membrane ducts.
 They are very prominent in some
individuals, whereas in others they are
barely visible or may be absent.

USUALLY THE
POSTERIOR
VIBRATING LINE IS
FOUND ,2 MM
ANTERIOR TO THE
FOVEAE PALATINE,
BUT THEY CAN BE
FOUND ON OR
ANTERIOR TO THE
VIBRATING LINE.

Review of Literature
(1) J Prosthet Dent: 1975; 33,504-510.
T.L.Lye conducted clinical, radiographic
and histological studies of fovea palatine and
concluded that, fovea palatine were positioned
1 .31 mm in front of the vibrating line in 70% of
the cases.
Histologically, complex nerve endings
were found just anterior to the fovea and
spreading to the soft palate.

Dental.J.1983:28; 166-70.
 A clinical study was conducted by S.B.Keng and ROW
A.M.,on edentulous patients to determine the distance of the
vibrating line to the fovea palatine. The results indicated that
the vibrating line is located 2.62 mm. (mean of 160 subjects)
anterior to the fovea palatine.
 There was a significant correlation between the distances of
vibrating line to the fovea for different type of soft palate
contour. Soft palate with deep slope (class III) has the
vibrating line at or just in front of the fovea, while class II
medium contour was 2.3 m.m. anterior to fovea, and class I
flat contour of the soft palate line located approximately 4
m.m. anterior to the fovea palatine.

FOVEA PALATINI AND POSTERIOR BORDER OF
DENTURE
 According to Boucher as fovea palatini are close to
vibrating line and always in soft tissues, which
makes them an ideal guide for location of posterior
border of denture.
 According to Winkler fovea palatini should be used
only as guidelines to the placement of posterior
palatal seal. The dentist who observes the fovea and
utilizes these anatomic landmarks as posterior
extent of denture base can deprive his patients of
several millimeters up to a centimeter or more of
tissue coverage depending on the palatal
configuration.

 Anterior
vibrating line-
 Anterior vibrating line
is an imaginary line
located at the junction
of the attached
tissues overlying the
hard palate and the
movable tissues of
the immediately
adjacent soft palate.
Vibrating lines of palate-www.indiandentalacademy.com

 This can be located either by valsulva
maneuver or by instructing patient to say
“ah” with short vigorous bursts.
 Due to projection of posterior nasal spine
anterior vibrating line is not a straight line
between hamular processes.
 At the midline it usually passes about 2 mm
in front of the fovea palatinae.

 Posterior vibrating line is an imaginary line at the
junction of the aponeurosis of tensor veli palatini
muscle and the muscular portion of the soft
palate.
 It represents the demarcation between that part
of the soft palate that has limited or shallow
movement during function and the remainder of
soft palate that is markedly displaced during
function.
 Posterior vibrating line is visualized by
instructing the patient to say “ah” in a normal
unexaggerated fashion.

 Direction of the vibrating line usually varies according
to the shape of palate ; the higher the vault , the more
abrupt and forward the vibrating line. In a mouth with
flat vault , the vibrating line is usually farther posterior
and has a good curvature, affording a broader PPSA.
 The M.M.House classification is customarily used to
designate the shape of the soft palate and it
describes the amount of posterior tissue that will
accept the posterior palatal seal –

Class I – More than 5mm of
movable tissue available for
post damming .
 ideal for retention.
Class II – 1-5 mm of movable
tissue available for post
damming.
 retention is usually possible.
Class III – Less than 1 mm
movable tissue available for
post damming.
 Retention is usually poor.

1. Irving R. Hardy and Krishan K. Kapur.
Posterior border seal –Its rationale and
importance J Prosthet Dent.1958;8;386-397
• Due to the relative instability of the denture
base materials generally used, we have to take
added precaution of scoring the cast at the deepest
point of the posterior palatal seal to counteract the
warpage of the denture.
• If this bead causes any irritation when the
denture is worn, it can be buffed off very easily, and
it may make the difference between excellent and
merely passable retention.

2. J prosthet.Dent.1971;25,470-488.
Sidney I. Silverman-
 He did a study on 500 patients who
required complete denture. The clinical
findings were evaluated during speech,
swallowing and respiratory posture.
 Silverman concluded that complete
maxillary denture can be extended for an
average of 8.2 mm. dorsally to the vibrating line.
 The extension varies from 4 to 12 mm.

3. J.Prosthet.Dent1973:23:484-93.
William E. Avant did a study to do comparison of
different type of palatal seal in relation of
complete denture retention.
 Conclusions of this study were –
1. A posterior palatal seal is necessary for
optimum retention of maxillary complete
dentures.
2. Each type of posterior palatal seal tested in
this study increased retention effectively.
3. No one type of posterior palatal seal that
was tested ,proved to be superior than other.

4) J.Prothet .dent.1975:34; 605-13.
H.Nikoukari did a study at school of dentistry, Mashad,
Iran.
This study was designed to measure the dimension and
displacement pattern of the posterior palatal seal in different
palatal shapes .The effect of different materials on the
displacement of tissue in the posterior palatal area were also
evaluated .
 It was concluded that the best posterior palatal seal can be
achieved by using green modeling compound or korecta wax
no 4 .
 For establishing the posterior palatal seal area ,the posterior
border should only be scraped on the cast for better
adaptation.
 No apparent changes of tissue displacement were found in
different palatal shapes. However width of the posterior palatal
seal area in flat palate was greater than deep and medium
palate.

5.Journal of prosthetic dentistry 2003;12 :265-270
Behnoush Rashedi and Vicki K Petropoulos, conducted a
survey of U.S. dental schools in 2001 ,to determine the
concepts, techniques used for establishing the post palatal
seal Results from this survey show that
 Combinations of clinical methods were most frequently
taught for locating the vibrating line.
 The phonation of the “ah” sound was the most popular
single method taught for locating the vibrating line.
 Most dental schools (87.5%) teach students to carve
the posterior palatal seal on maxillary master cast.
 Most dental school (93.9%) take the compressibility of
the palatal tissue into consideration when carving the depth of
posterior palatal seal in maxillary master cast.

Anatomy of supporting structures
in maxillary region-

 The foundation for dentures is made
up of bone of the hard palate and residual
ridge, covered by mucous membrane. The
denture base rests on the mucous
membrane, which serves as a cushion
between the base and the supporting
bone.

Residual alveolar ridge-
Definition (According to GPT-8) –
“The portion of the alveolar ridge and its
soft tissue covering ,which remains
following the removal of teeth.”
 The socket that surrounds the root
of each natural tooth is called alveolus and
the bony ridge that supports the teeth is
the alveolar ridge.

 When the natural
teeth are removed, the
alveoli begin to fill up
with the new bone. At
the same time bone
around the margins of
tooth sockets begin to
shrink away.
 This shrinkage or
resorption is rapid at
first six weeks of tooth
removal, and it
continues at a
reduced rate throughout the life and is responsible
for the formation of RAR.

The alveolar ridges vary greatly in size,
shape and their ultimate form. This is
dependent on the following factors -
 Variation in bone size and its degree
of calcification in individuals.
 Teeth show wide individual variation in
size. Large teeth are supported by bulky
ridges and smaller teeth by narrow ones.
 The amount of bone lost prior to the
extraction of teeth.
 The amount of alveolar process removed
during extraction of teeth.

 Rate and degree of resorption: - During the
first six weeks after the extraction of teeth, the
rate of resorption is rapid, thereafter it continues
throughout the life at an ever decreasing pace.
 The effect of previous denture: - ill fitting
denture, or dentures with occluding natural
teeth, may cause rapid resorption of the alveolar
process in the areas where they cause
excessive pressure or lateral stresses.
 The relative length of the time for which
different parts of the jaw has been edentulous.
 Person’s general health.

 According to size RAR can be-
-large
-medium
-small

large medium
small

 According to shape RAR can be-
- smooth
- irregular
- knife edge
- flat

IrregularSmooth
Knife-edgeFlat

TYPES OF ALVEOLAR RIDGES,
PALATE FORMATION AND THEIR
SIGNIFICANCE

square to gently
rounded
This is most
favorable kind of
ridge because –
 The centre of
the palate presents
an almost flat
horizontal area and
this will aid in
retention.
 The roomy
sulcus allows for the
development of good
peripheral seal.
Flat surface
 The well developed ridges resist lateral and anteroposterior
movement of the denture.

tapering or V’
Shaped
• It is usually
associated with thick
bulky ridges. This is
an unfavorable
formation.
The forces of
adhesion and
cohesion are not at
right angles to
surface when
counteracting the
normal displacing
forces of gravity.
V’ shaped

(iii) Flat palate with small
ridges
This is an
unfavorable formation
because –
 The poorly
developed ridges do
not resist lateral and
anterior-posterior
movement of the
denture.
 Shallow Sulcus
do not form a good
Peripheral seal.
Shallow Flat Palate

 Unsupported
alveolar soft tissues
are frequently found
in the edentulous
anterior maxilla
which has been
opposed by an
island of natural
anterior teeth with an
edentulous posterior
mandible.
 During mastication
the upper denture
‘see-saws’ leading to
disproportionate
resorption.

 Soft tissues are
compressible
and the denture
develops
increasing
instability.
 Excessive soft
tissue needs
surgical
removal.

MICROSCOPIC FEATURES OF RESIDUAL
RIDGES
 The mucous membrane is
attached to the
periosteum of the bone by
the connective tissue of
the sub mucosa.
 The stratified squamous
epithelium is thickly
keratinized.
 The sub mucosa is
devoid of fat or glandular
cells and it is
characterized by dense
collegenous fibers that are contiguous with lamina
propria.

 The outer surface of
bone in the region of
crest of RAR (most
coronal portion of
ridge) is usually
compact in nature.
This compact bone in
combination with
tightly attached
keratinized mucous
membrane makes
crest of RAR
histologically best
able to provide primary
support for the
denture.

RAR- a primary stress bearing area
???
 According to Prosthodontic Treatment for
Edentulous Patients by Zarb and Bolender-
“the bone in this region is subject to
resorption, which limits it’s potential for
support, unlike the palate, which is resistant
to resorption. Because of this, ridge crest
should be looked on as a secondary
supporting area.”

 They
Consider
“horizontal
portion of
hard palate
lateral to
midline” as
primary
supporting
area for
denture.

 In a patient
where tooth were
extracted long
time back
(years), ridge
becomes
smaller and crest
of ridge in many
cases is
completely
devoid of smooth
cortical bony
surface.
 Horizontal part of palate lateral to midline should
definitely be considered a primary stress bearing area
in these patients.

PALATAL REGION-
Rugae area-
 Rugae are the raised area of dense connective
tissue radiating from the median suture in the
anterior one third of the palate.
 Consists of series of ridges in the anterior part of
the hard palate
 Mucosa is keratinized and the submucosa is
fibrous
 In the area of the rugae, the palate is set at an
angle to the residual ridge and is rather thinly
covered by soft tissue.

 This area contributes to the stress-bearing
role as well as to retention although in a
secondary capacity.
 It resists forward movement of denture.
 It should be recorded without pressure, if it
distorts while making impression it can rebound
and unseat the denture.
 These folds of the mucosa play an important
role in speech so dentures should reproduce this
contour making it very comfortable for the
patient.

Mid palatine raphe-
 This presents as slightly
elevated bony ridge along
the midline of hard palate.
 Adequate relief should be
provided in this area as-
- mucosa covering the
raphe is extremely thin and
is traumatized easily.
-mucosa is less resilient
than that covering the ridges
so it can act as fulcrum
along which denture rocks
when vertical forces are
applied.

 This area
provides primary
support to
denture as it
offers maximum
resistance to
resorption.
Horizontal portion of hard palate lateral to
midline-

Lateral surface of hard palate
It is divided in
 anterolateral part containing adipose
tissue in submucosa
 posterolateral part containing
glandular tissue.
Both of these areas are displaceable they
do not provide significant support to the
denture but this region should be covered
to provide retention.

Anteriolateral View Posteriolateral View

 These areas should be recorded in
resting condition because when they are
displaced in the final impression, they tend
to return to natural form within the
completed denture base, and creating an
unseating force on the denture or causing
soreness in the patients mouth. For
recording these tissue in undistorted form,
proper relief should be given in the final
impression tray.

INCISIVE PAPILLA-
 This covers
the incisive
foramen and
is located in
the midline
immediately
behind and
between
central
incisors.

Prosthodontic
significances:
 It lies nearer to
the crest of the
ridge as resorption
progresses. Thus
the location of the
incisive papilla
gives an indication
as to the amount of
resorption that has
taken place.

 Incisive papilla
acts as a guide for
antero-posterior
positioning of the
teeth, the
labial surfaces of
the central
incisors are
usually 8-10 mm
in front of the
papilla.

 Incisive
papilla is used
to locate the
midline of the
dental arch.

The nasopalatine nerves and blood vessels pass
through the foramen, and care should be taken that
the denture base does not impinge on them.

1. Harold R. Ortman, and Ding H. Tsao
:Relationship of the incisive papilla to the
maxillary central incisors. J Prosthet
Dent 1979;42; 492-496
 A study on 38 maxillary casts found that the
average distance between the most anterior
point of maxillary central incisors and most
posterior point of the incisive papilla was 12.454
mm .

2.J.prosthet.Dent 1981:45;592-97.
G.M.Retechie did a study at
dental school London ,UK.
An investigation of 64 angle
skeletal class I dental students
showed that the incisive papilla
provides a stable anatomic
landmark for arranging the labial
surface of the central incisors
labial surface is 10.2mm
anterior to the posterior border of
the papilla.

3) Journal Indian Dent.Asso.1984:56;425-28.
Kharat D.U. and Madan R.S. carried out a study on
200 subjects (108 men,98 women) of different age group
ranging 20-65 years ,to determine the distances from
incisal edge of the maxillary central incisor to the
papilla.
 The findings of the study showed that the mean
distance of maxillary incisal edge to the incisive papilla
was 8.16 + 1.26 mm for men and 7.41 + 0.98 mm for
women.
 Conclusion of their study was, the distance from
maxillary incisal edge to the incisal papilla in dentulous
men is more than the women and this distance remains
constant throughout the life.

(4) J.Prosthet.Dent.
1987:57;712-14
A.M.H.grave and
P.J.Becker compared the
position of incisive papilla,
in between the two groups
in their study. The first
group consisted of existing
complete upper dentures of
67 patients(34 men,33
women). And another
group consisted of cast
obtained from the 60 young
adults.

 The results of the study suggests that the
labial surface of the maxillary incisors
should be 12-13 mm from the posterior
border of the incisive papilla. These
measurements was significantly smaller in
the sample of dentures examined , which
suggests a tendency for anterior teeth to be
placed too far posteriorly in artificial denture.

(5) J.prosthet.Dent.
1989:61;51-53. H.F.
Grove and L.Cristensen
did a study on 58 subjects
to determine the
orthographic distances
from the posterior of the
incisive papilla to the line
intersecting the distal
contact point of the
maxillary canine.
In 92% of subjects the posterior point of incisive papilla
was approximately 3mm anterior to the line between
the distal points of the canines. Neither gender, age,
nor maxillary arch form affected this distance.

 Also called
malar process is
located opposite
the first molar
region and is
commonly seen
in mouth that has
been edentulous
for long.
Zygomatic process-

 Some
dentures
require relief
over the area
to aid in
retention and
to prevent
soreness of
underlying
structures.

MAXILLARY TUBEROSITY-
 Maxillary
tuberosity
represents
most distal
portion of
maxillary
alveolar
ridge.

 The tuberosity
region often
hangs abnormally
low when
maxillary posterior
teeth are retained
after mandibular
molars are lost
and not replaced,
the max. teeth
extrude bringing
the tuberosity with
them.
 Often the low hanging tuberosity prevents proper
location of occlusal plane.

 Most often
tuberosity
enlargements are
only fibrous in
nature.
 In either case
invasion of
interalveolar
space in the
tuberosity area
may prevent the
posterior
extension of
denture .

REVIEW OF LITERATURE-
1.JADA vol. 103, Dec 1981,
894. Ryle A. Bell, and
Richardson.
2.Quintessence international
1987 :18;465. Sherif E,
John unger and Carl Stone
 They have presented
techniques of non surgical
managemant of
overhanging tuberosities for
CD patients.
 Overhanging tuberosities in these cases reduced
intermaxillary space to less than 3 mm. This space did
not allow for the adeqate thickness of U and L acrylic
denture bases.

 Before the record
bases were
constructed, the
tuberosities were
outlined on the cast.
In these areas
either type-3 gold
alloy or co-cr alloy
was used as
denture base
material in place of
acrylic resin.

3.J.Prosthet.Dent.
2004;92:128-31.
Leonard Garth Lowe
presented a clinical report
for the non surgical
management of bilateral
undercut in tuberosity
region. They made
decision to incorporate
flexible flanges in the
undercuts using resilient
silicon lining material to
allow adequate height and
thickness of the denture
flange.

Sharp spiny processes-
 There are sharp spiny processes on
max. and palatal bone that are normally
deeply covered by soft tissues but in
patients with considerable RAR resorption
these processes irritate soft tissues .
 Canal leading from a posterior palatine
foramen often has a sharp overhanging
edge that may irritate palatal mucosa.

Torus palatinus-
 Seen as a hard bony enlargement that occurs
in midline of the roof of mouth is called torus
palatinus.
 Seen in nearly 20% of population
 2 types
-almost entirely soft tissue, loose and flabby
- thin layer of mucosal tissue covering the bone
 Dentures require relief over this area to aid
retention and prevent soreness of the underlying
tissues.

 A smooth
rounded small
torus does not
normally create
much problem
as denture
plate may be
cut away to
avoid tori or
can be
extended over
it with proper
relief.

 A large,
irregular, lobbed
tori should be
treated
surgically as
cutting away the
denture plate
significantly
reduces denture
retention and
also leads to
excessive ridge
resorption.

REFRENCES
CHARLES M.HEARTWELL, JR
ARTHUR O.RAHN
(4th EDITION)
A ROY MACGREGOR
(3RD EDITION)
SHEDON WINKLER
(2ND EDITION)
ZARB.BOLENDER
(12TH EDITION

1. R. T. Hill. Anatomy of interest to the prosthodontist.
J Prosthet Dent.1955; 5; 109-111
2. G. A. Lammie. Aging changes and the complete
lower denture. J Prosthet Dent.1956; 6; 450-464
3. John O. Neufeld. Changes in the trabecular pattern
of the mandible following the loss of teeth. J
Prosthet Dent.1958; 8; 685-697
4. Irming R. Hardy and Krishan K. Kapur posterior
border seal – its rationale and importance. J
Prosthet Dent. 1958; 8; 386-397

6. Joseph S.Landa. Trouble shooting in complete
denture prosthesis. Part I. Oral Mucosa and border
extension. J Prosthet Dent.1959; 9; 974-987
7. Rovert B. Lytle Soft tissue displacement beneath
removable partial and complete dentures. J
Prosthet Dent.1962; 12; 34-43
8. Thomas E. J. Shanahan. Stabilizing lower dentures
on unfavorable ridges. J Prosthet Dent.1962; 12;
420-424
9. H. R. Kolb. Variable denture-limiting structures of
the edentulous mouth. J Prosthet Dent. 1966; 16;
194-201
10. H. R. Kolb. Variable denture limiting structures of
the edentulous mouth. J Prosthet Dent. 1966; 16;
202-212

11. Donald E. Van Scotter and Louis J.
Boucher. The nature of supporting tissues
for complete dentures. J Prosthet
Dent.1965; 15; 285-294
12. Ellsworth K. Kelly. The prosthodontist, the
oral surgeon and the denture-supporting
tissues. J Prosthet Dent. 1966; 16; 464-478
13. Philip M Jones and LeRoy K. Nakayama.
Surgical experiences of complete denture
patients. J Prosthet Dent. 1967; 18; 12-18
14. K. W. Tyson. Physical factors in retention
of complete upper dentures. J Prosthet
Dent. 1967; 18; 90-97

15. Sidney I. Silverman. Dimensions and displacement
patterns of the posterior palatal seal. J Prosthet Dent.
1971; 25; 470-488
16. John L. Shannon. The mentalis muscle in relation to
edentulous mandibles. J Prosthet Dent. 1972; 27; 477-
484
17. Wlodzimierz Jozefowicz. Cushioning properties of the
soft tissues forming the basal seat of dentures. J
Prosthet Dent. 172; 27; 471-476
18. L. Lye. The significance of the fovea palatini in
complete denture prosthodontics. J Prosthet Dent. 1975;
33; 504-510
19. H. Nikoukari a study of posterior palatal seals with
varying palatal forms. J Prosthet Dent. 1975; 34; 605-
613
20. Harold R. Ortman and Ding H. Tsao. Relationship of
the incisive papilla to the maxillary central incisors. J
Prosthet Dent. 1979; 42; 492-496

21. Ming-Sheh Chen. Reliability of the fovea palatini for
determining the posterior border of the maxillary denture. J
Prosthet Dent. 1980; 43; 133-147
22. Aust.Dent.J.1981:26;218-21.
23. Ian b. Watson and D. Gordon Macdonald. Regional variation
in the palatal mucosa of the edentulous mouth. J Prosthet Dent.
1983; 50; 853-859
24. T. E. Jacobson and A. J. Krol. A contemporary of the factors
involved in complete denture retention, stability, and support.
Part I: Retention. Part II: stability Part III support. J Prosthet
Dent. 1983; 49; 5,165,306
25. J.Prosthet.Dent.1987:57;712-14
26. J.Oral.Rehab.1988:15;133-39.
27. H. F. Grove and L. V. Christensen. Relationship of the
maxillary canines to incisive papilla. J Prosthet Dent. 1989; 61;
51-53

28. G. C. D. Kau and R. F. K. Clark. The relationship of the
incisive papilla to the maxillary central incisors and
canine teeth in southern Chinese. J Prosthet Dent.
1993; 70; 86-93
29. J.Prosthet.Dent. 2004;92:128-31
30. Sheldon Winkler. Essentials of complete denture
prosthodontics. 2nd edition
31. Zarb-Bolender Prosthodontic treatment for edentulous
patients.12th edition
32. Fenn, liddelow and Gimsons`s :Clinical dental
prosthetics. 3rd edition
33. Verrill G. Swenson: Complete dentures 4th edition
34. Charles M. Heartwell: textbook of complete dentures.
5th edition

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