Mounting 1/certified fixed orthodontic courses by Indian dental academy

MOUNTANTS
INDIAN DENTAL ACADEMY
LEADER IN CONTINUING DENTAL EDUCATION
www.indiandentalacademy.com

LEARNING OBJECTIVES
 At the end of the seminar the learner should be
able to describe about:
 Uses of mounting
 Types of mounting
 Mountants

REFERENCES
1. Cellular Pathology Technique ,C.F.A Culling
,R.T Allison,W.T Barr. 2nd Ed.
2. Theory and Practice of Histological Technique
,John D Bancroft , Marlyn Gamble. 5th Ed.
3. Principles and techniques in histology and
microscopy, Dr.D.R.Singh. 1st Ed.
4. Theory and Practice of Histological Technique
,John D Bancroft , Marlyn Gamble. 6th Ed.

INTRODUCTION
 Mounting- A backing, setting or support something.
 According to some it means attachment and is used
to designate affixing of sections to the slides.
 However, more often it is used to denote placement
of some material over the section before covering it
with coverslips.

USES OF MOUNTING
 To maintain a high refractive index
 To protect the specimen
 Mounting medium holds the sections in place
between the cover slip and the slide.

TYPES OF MOUNTING
 Wet mounting
 Dry mounting
 Prepared mount

WET MOUNTING
 In a wet mount, the specimen is placed in a drop
of water or other liquid held between the slide and
the cover slip by surface tension.

 This method is commonly used to
view microscopic organisms that grow in pond
water or other liquid media, especially when
studying their movement and behavior.
 It is also used to examine physiological liquids
like blood, urine, saliva, semen and vaginal
discharge

DRY MOUNT
 In a dry mount, the simplest kind of mounting, the
object is merely placed on the slide.
 This mounting can be successfully used for viewing
specimens like pollen, feathers, hairs, nails,skin etc.

PREPARED MOUNTING
 For histological examination the specimen has to
undergo a complex processing.
 This may involve cutting it into very thin sections
with a microtome, fixing it to prevent
decay, dehydrating , staining it, and impregnating
or infiltrating it with some transparent solid
substance.
 As a result of this process the specimen usually ends
up firmly attached to the slide.

TECHNIQUE
1.
• Sections to be mounted is taken out from xylene bath
with forceps .
2.
• The ends are first cleaned so that diamond inscribed
number and front of slide where section is placed is
seen.
3.
• Back of slide and excess xylene from the front
(2-3 mm of margin of the section) is wiped off

4.
• A streak of mounting media is placed on the centre
of slide using a small glass rod
5.
• Slide is placed lengthwise with its edge touching the
edge of the coverglass and inverted over it.

• Ooze out at sides of coverglass
• Wipe it with fine cloth dipped in
xylene
Too much
mounting media
• As medium sets it will draw
away from the edges of the
coverglass
If too little or too
dilute mounting
media

MOUNTING MEDIA

COMPOSITION OF MOUNTING MEDIA
 Mounting media comprise two or three main
ingredients:
1. A base,
2. An antifade reagent and
3. A plasticizer to set.

THE BASE
 Base is the major determinate of the refractive index
of the medium.
 Natural oils and plastic-base mounting media tend
to be hydrophobic, and therefore require
dehydration of the sample: this may cause
significant shrinkage of tissue.
 Aqueous and glycerol-based media are hydrophilic
and do not require the sample to be dehydrated.

CLASSIFICATION
They fall into two main classes :
 Aqueous media
 Resinous media

AQUEOUS MOUNTING MEDIA

 Used for sections which is unstained, stained for fat,
metachromatically stained or following
immunofluorescent and certain enzyme
histochemical methods.
 Those methods where the action of alcohol or xylene
would be detrimental to the stained preparation.

AQUEOUS MOUNTANTS
Three types:
 The syrups
 Gelatin media
 Gum arabic media

GLYCERINE JELLY (RI-1.47)
 Useful for making mounts of water organisms,
algae, protozoa, etc.
 Glycerol jelly according to Kisser is commonly used
to preserve pollen samples.
 It is used as standard mountant for fat stains.

COMPOSITION
Glycerin 10gm Prevents
cracking or
splitting
Distilled
water
70ml Solvent
Gelatin 60ml Key
ingredient
Phenol 0.25gm bacteriostatic

Advantages

Water based avoids need of alcohol dehydration
which possibly deforms the specimens, and other
toxic organic solvents.

Does not shrink.
Disadvantages

Difficulty of mounting the sections

Need to seal the cover slip with nail polish.

GUM ARABIC
 Apathys medium
 Refractive index 1.52
 Used when an aqueous medium of higher
refractive index is required
 Useful for fluoresecent microscopy

COMPOSITION
CANE SUGAR 50GM ANTIFADE AGENT
DISTILLED WATER 50ML SOLVENT
GUM ARABIC 50GM BASE
THYMOL 0.05GM BACTERIOSTATIC

HIGHMAN’S MODIFICATION
 Recommended for use with metachromatic
stains

COMPOSITION
GUM ARABIC 20 GM BASE
CANE SUGAR 20 GM ANTIFADE
POTASSIUM
ACETATE
20 GM PREVENTS
BLEEDING
SODIUM
MERTHIOLATE
10 ML BACTERIOSTATIC
DISTILLED WATER 40 ML SOLVENT

FARRANT’S MEDIUM
 More convenient than glycerin jelly for mounting
 Disadvantage is takes longer time to set
 Air bubbles sometimes form during the setting
process

COMPOSITION
GUM ARABIC 50gm BASE
DISTILLED
WATER
50ml SOLVENT
GLYCERINE 50ml PREVENTS
CRACKING
ARSENIC
TRIOXIDE
1gm PRESERVATIVE

MOUNTANT IN FLUORESCENT MICROSCOPY
 Fluoro-Gel is an aqueous mounting medium for
preserving fluorescence of tissue and cell smears.
 This unique formula prevents rapid
photobleaching .
 The fluorescence is retained during prolonged
storage at 4ºC in the dark.

RINGING MEDIA OR SEALANTS
 Mounting media which dry back from the edges
or develop air bubbles should be coated at the
edges of the coverslip with a non-porous ringing
medium.
 When these dry, they are impermeable to water,
and protects glycerin-jelly, for example, from
desiccation and contraction.
 Keeps water out of hygroscopic media like
glycerin.

 It clings to glass and permits use immersion oil
without risking the displacement of the cover
ruining the preparation.
 The term ringing' originated because round
coverslips were then used and the coating
applied in the form of a circle or 'ring‘.

 Various ringing media are-
1. Dental or modelling wax
2. Cement such as plastic adhesive (such as
Durofix)
3. Entellan (methyl methacrylate)
4. Nail polish
5. A solvent-free sealant that can be used for live
cell samples is "valap", a mixture
of vaseline, lanolin and paraffin in equal parts.

RESINOUS MOUNTANTS

CANANDA BALSAM
 Natural mounting medium obtained from Canadian fir
tree (Abies balsamea).
 Composed of terpenes,carboxylic acid and their esters.
 Optical properties are nearly identical with those of
glass.

Advantages

Permanent slides mounted with canada balsam
have been stored for century and are still useful.
Disadvantages

The specimen must be placed into xylene before
embedding.

Canada balsam darkens with age

It slowly becomes acid because it oxidises xylene
to toluic and phthalic acids

This acidity causes gradual fading of many
stains.

Not cheap

KIRKPATRICK AND LENDRUM’S DPX

DPX, was introduced in 1939 .

Earlier tricresal phosphate was used as
plasticizer.

RI-1.52

COMPOSITION:

Distrene 10g

Dibutylpthalate 5 ml

Xylene 35ml

 C18H18N2.2Br
 Used in most of the routine mounting procedures.
 Advantage of its use being that it can be easily
stripped off from the sides of coverglass.
 They are not recommended for use with thick
sections as there is a danger of retraction of the
mountant upon drying

EUPARAL (RI-1.48)
 Semisynthetic mountant
 Invented in 1904 by Prof. G. Gilson, Professor of
Zoology at Louvain University, Belgium.
 Euparal possesses a nice odor due to the natural oils
that are included.
 Commonly used to mount histological sections and
insects.

Sandarac
Eucalyptol
Paraldehyde
Camphor +Phenyl salicylate
= camsal
Advantages Disadvantage
The possibility to directly
transfer sections from alcohol
to euparal without the need
of toxic solvents.
Relatively long drying
time
COMPOSITION

MOUNTING WITHOUT COVERSLIPS
 Using resin sprays.
 These sprays harden on application and serve as
both mountant and the coverslips.

MOUNTANT FOR PHASE CONTRAST MICROSCOPY
 A new synthetic resin designed for use as high
refractive index microscopic slide mounting agent
for diatom samples.
 It is a condensation product between napthelene
and formaldehyde.
 RI-1.7

REFRACTIVE INDICES OF MOUNTING MEDIA
 One, of the important functions of mounting media
is to enhance the transparency of the section.
 Most of the mounting media, therefore, possess their
refractive indices close to that of the glass.

Name of the media Refractive index
Air 1.000
Absolute alcohol 1.367
Glass ( crown ) 1.518
Canada balsam - Solid 1.535
In xylene 1.524
Egg albumin solution 1.350
Glycerine jelly 1.470

Name of the media Refractive index
Glycerin - Pure 1.470
aqueous 1.397
Liquid paraffin 1.471
Xylene 1.497
Water - Distilled 1.336
Sea 1.343

SUMMARY
Aqueous
media
Temporary
medias
Useful for immunofluorescent
techniques, mounting sections
of fat stains
Resinous
media
Permanent
medias
Routinely used - DPX
 Mounting media are needed for making
permanent slides for microscopy and storage.

THANK YOU

Mounting 1/certified fixed orthodontic courses by Indian dental academy

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