soldering and welding in orthodontics

31.07.2012 soldering and welding 1

TOPIC-
SOLDERING AND WELDING

UNDER THE GUIDANCE OF –
DR. MOHAMMAD MUSHTAQ
HEAD OF THE DEPARTMENT

“Never must the physician say the disease is incurable.
By that admission he denies GOD , our creator ; he
doubts Nature with her profuseness of hidden
powers and mysteries”.

PARACELSUS


Since it is not always possible to create a metal
device in one piece, such as by casting, it is
necessary assemble it from separately prepared
parts. In dentistry, the fabrication techniques
used are either soldering or welding.
 Nuts and bolts
 Adhesives


Are divided into three categories

• SOLDERING

• BRAZING

• WELDING

31.07.2012 5
soldering and welding

 The soldering technique has been known to man for
hundreds may be thousands of year. However , with
industrial revolution in Europe as well as North America
, the need for higher temperature and more user friendly
tools emerged.

 It was discovered that when the vapor from heated alcohol
was ignited over a burning wick, it burnt with a very
concentrated flame of high temperature very suitable for
different heating purposes.

 After the second world war, the PROPANE gas emerged as
a cleaner and safer fuel for different heating purposes. The
introduction of propane caused a lot of changes in the blow
lamp industry world –wide.


 The appliance had a metal framework. The attachment of
axillaries to bring about the different type of tooth
movements required soldering of these parts.

 Welding in orthodontics became popular because of the
short time required, the ease of welding and the absence
of elaborate equipments


 SOLDERING is defined as the joining of metals by the
fusion of filler metal between them, at a temperature
below the solidus temperature of the metals being
joined and below 450° C.

 The American National Standards Institute (ANSI)
currently is considering a proposal to call all joining
operations in dentistry as brazing rather than
soldering. Thus brazing may be the predominant term
in the future.


The soldered joint consists of the following
components:

A). Parent metal
B). Fluxes and anti- fluxes
C). Solder or filler metal


The parent metal is the metal or alloy to be joined.
It is also known as substrate metal or base
metal. Soldering operation is the same for any
substrate metal.
The composition of parent metal determines:
 melting range

 oxide that forms on the surface during heating

 wetablitly of the substrate by the molten solder


 In Latin the word flux means “to flow”

 Purpose of flux is to remove any oxide coating
on the substrate metal surface when the filler
metal is fluid and ready to flow into place.
They protect the alloy surface from oxidation
during soldering and dissolve metallic oxides
as they are formed. The resulting solution of
oxides or other extraneous matter in flux
constitutes

 i. According to their primary purpose
TYPE I – surface protection
TYPE II – reducing agent
TYPE III – solvent


ii. According to pH of the flux
Acidic flux – SiO2
Basic flux – CaO, Lime CaCO3, limestone
Neutrals – fluorspar (CaF2,), Borax (NaBO2)


 iii. Based on boric or borate compounds
TYPE I – protective fluxes by forming a low-
temperature glass
TYPE II – reducing fluxes low stability oxides
such as copper oxides
TYPE III – fluoride flux


Also called as sodium borate, or sodium
tetraborate or disodium tetraborate. They are
based on boric or borate compounds such as
boric acid, boric anhydrate and borax. It is
usually a white powder consisting of soft
colorless crystals that dissolve easily in water.


They are available in different forms such as-
 Liquid form- solution of borax/boric acid in
water, indicated for soldering of orthodontic
appliances and bridges in which minimum amount
of flux is required.
 Paste form- formed by mixing borax with
petroleum jelly. Required when fluxes are needed
in large quantity.
 Powder form- contains a mixture of borax, silica
flour and finely divided charcoal. Charcoal is
reducing agent and silica holds molten flux in
surface of hot metal. This is usually used for
casting operations


Composition of fluoride fluxes is-
 Potassium fluoride – 50-60%
 Boric acid – 25-35%
 Borax glass – 6-8%
 Potassium carbonate – 8-10%
As the choice of flux is dictated by the type of alloys to
be soldered, the fluoride flux is used with alloys
containing base metals even if a gold/silver is used.
Some fluoride containing fluxes involve toxic fluorides
when heated, so inhalation of fumes should be
avoided.


The chemical compound with the formula KF.
After hydrogen fluoride. KF is the primary
source of the fluoride ion for appliances in
manufacturing and in chemistry. It is an alkali
metal halide and occurs naturally as the rare
mineral carbobite (potassium -67.30% +
fluorine -32.70%).


A combination of high melting salt is used as fluxes to
combine the good characteristics of each ingredient
and create superior flux.

A formula for effective flux is
 Borax glass- 55 parts
 Boric acid – 35 parts
 Silica – 10 parts

The ingredients may be fused tighter and then crushed
to a fine powder.


The following points are to be considered -

 Painted on the substrate metal at the junction of pieces
to be joined.
 Fused on the surface of the parent metal strip.
 Whatever is the technique used the most important
thing to be considered is the amount of flux to be used.
 Too little of flux burns off and tends to be ineffective.
 Excess flux remains trapped in the filler metal and
weakens the joint.
 Flux combined with metal oxide forms glass that is
difficult to remove complete


Materials used to restrict flow of solder are
known as anti-flux. It is applied on the specific
area where the flux should flow into. It is
applied before applying flux or solder.
 E.g. Graphite in the form of lead pencil.
Disadvantage of graphite is that it can burn off
on prolonged heating at high temperature.
 In such case whiting CaCO3 in alcohol and
water suspension is used.


Qualities of an ideal solder:
 Ease of flow at relatively low temperature.

 Sufficient fluidity to freely flow when melted.

 Ability to wet substrate metal.

 Strength compatible with that of structure
being joined.
 Resistance to tarnish and corrosion.

 Acceptable color to give an inconspicuous joint.

 Resistance to pitting during heating.


 A rule of thumb is that flow temperature of the
filler metal should be 56° C(100° F) lower than
the solidus temperature of the substrate metal.
If the flow temperature of the filler metal is
above or close to solidus temperature if the
substrate an alloying can take place. An alloy
formed through diffusion can have properties
different from the filler as well as substrate
metal.


 SOFT SOLDERS AND HARD SOLDERS

 PRECIOUS METAL SOLDERS AND NON –
PRECIOUS METAL SOLDERS


Has good tarnish and corrosion resistance. Extensively
used for crown and bridge applications.

Composition:
 Gold – 45-81 wgt%
 Silver – 8-30 wgt%
 Copper – 7-20 wgt%
Small amounts of tin, zinc and phosphorus are added to
modify fusion temperature and flow qualities. They are
high fusing with a fusing temperature range of 750°C -
900°C.


They are used in orthodontic appliances. White solders are usually
required for stainless steel and chromium – based alloys foe color
matching. Their formulation is very similar to gold solders, with
the omission of the gold11. They are low fusing temperature 600 -
750° C. They are used with stainless steel or other base metal
alloys. Their resistance to tarnish and corrosion is not as good as
gold solders. But they have strength comparable to gold solders.

Composition:
 Silver – 10 – 80%
 Copper – 15 -30%
 Zinc – 4 – 35%
 With small amounts of cadmium, tin, phosphorus.


The most common instrument used as heat source is gas- air or gas
oxygen torch.
Fuels used are-
 Hydrogen- low heat content, so heating is slow
 Natural gas – heat content is 4 times that of hydrogen.
 Acetylene - high flame temperature, but variation in temperature
from one apart of the flame to the other part is more than 100° C.
so, positioning of torch is critical. It is chemically unstable
gas, decomposes to carbon and hydrogen. Carbon can get
incorporated in to nickel and palladium alloy.
 Propane – is the best choice. It has the highest heat & good flame
temperature.
 Butane – has similar flame temperature and heat content. Both are
readily available. Uniform in quality, virtually water free and
burn clean.


The flame has been divided into four zones. (picture)
 Cold mixing zone ( unburned gas)
 Partial combustion zone (oxidizing)
 Reducing zone
 Oxidizing zone ( burned gas)
The portion of the flame used for heating the soldering
assembly should be neutral or slightly reducing part.
Because this produces the most efficient burning and the
critical heat. Improperly positioned flame or improperly
adjusted torch can lead to oxidation of the substrate or filler
metal and result in poorly soldered joint. If unburned part of
flame is used it may lead to incorporation of the carbon in
the filler or the substrate. To prevent oxide formation flame
should not be removed once its applied to the joint that is to
be soldered until the soldering process is complete.




Fig: zones of the flame


 OVEN (FURNACE) SOLDERING

 INFRA- RED SOLDERING


A furnace with enough wattage to provide
heat required to raise the temperature of the
filler metal to its flow point is used.

 Advantages of oven (furnace) soldering are:
1. Uniform temperature
2. Close monitoring is possible
3. Temperature is known
4. Application of vaccum control oxidation.


The unit uses light from a 1000 watt Tungsten.
 Quartz – iodine bulb which is mounted at the
primary focal point of a gold pointed elliptical
reflector is used.
 The material to be soldered is placed at the
reflectors secondary focal point at which
reflected infra red energy of Tungsten light
source is focused.
 This is used for high temperature soldering.


 INVESTMENT SOLDERING

 FREE HAND SOLDERING


It is used when very accurate alignment of
parts to be joined is needed. The parts are
placed on the master cast with a gap of at least
1mm. The parts are fastened with sticky wax
before placing soldering investment. The
investment is preheated to eliminate moisture.
Soldering is carried out with reducing flame at
750 – 870 ° C. The investment is cooled 5
minutes before quenching. Flux will cool to a
glass which is removed by pickling.


Free hand soldering is used for soldering
orthodontic appliances. Orthodontic torches
can be placed on a bench so that both hands
can be used to hold the parts in position.


 If the gap is too great the strength will be
controlled by the strength of the filler.

 If the gap is narrow, the strength will be
limited by the flux inclusions and porosities by
the incomplete flow of the filler metal.


 Cleaning and preparing the surface to be joined.
 Assembling the parts to be joined.
 Preparation and fluxing of the gap surfaces between the gaps.
 Maintaining the proper position of the parts during procedure.
 Control of proper temperature.
 Control of time to ensure adequate flow of the solder & complex
filling of the solder joint.


Fig: Point contact offers inadequate strength


Fig: Wrapping the wire around gives the best type of
joint

Fig: Longer areas of joint help increase the joint
strength

Fig : thin wire is wound around the thick wire first of all

Fig : the joint before and after soldering


 In orthodontic application low temperature
soldering is used to prevent carbide precipitation
and to prevent excessive softening of the wire.
 Low fusing silver solders are used with a soldering
temperature range of 620 - 655° C.
 Fluoride fluxes are used for orthodontic stainless
steel and other base metal alloys.
 Free hand soldering technique is employed with a
needle like non- luminous gas air flame is used.
 The work should be held 3 mm beyond the tip of
the blue cone in the reducing zone of the flame.


 It is recommened that while soldering the rest
of the appliance should be covered with a
damp cloth.

 Soldering should be observed in a
shadow, against a black background, so that
the temperature can be judged by the color of
the work. The color should be “dull red”.
 Flux must cover all the areas to be joined before
heat is applied.
 As soon as the flux fused solder is
added, heating is continued until metal flows
around the joint. The work is then removed
from the heat and quenched in water.

When the solder has fused properly and has not been
overheated, a well – defined boundary forms
between the solder and the soldered parts.

A simplest method is to lay the structure on an
unexposed piece of intraoral radiographic film
and expose the film with an x-ray beam, using
an accelerating voltage of 90 kV and a current
of 10mA for 1second. Another film should be
exposed after rotating the appliance at a 90
degree angle to the initial orientation. One can
clearly see the radiolucent voids at certain area
that is soldered.


Soldering in dentistry is used for various
purposes,
 Inlays

 Crowns

 Fixed bridgework

 Removable partial dentures

 Orthodontic appliances


 Wire to wire
 Tube can be soldered to the bridge of the
Adam‟s clasp.
 Attachment of springs to arch wire, the solder
must be gold solder with a melting point below
800° C.
 Soldering lingual arch or palatal arch.


 A concentration of the composition of silver solder
reveal that any material containing up to about 20%
zinc & 20- 30% copper with additions in some cases of
low cadmium & tin content remain inactive to
physiologic solutions.
 Weak corrosion prone micro structural phases
composed mainly of copper and zinc has been shown
to occur within the solder itself. It is known that
corrosion occurs when an electrolyte comes into
contact with the soldered joint.
 The silver solders react readily to chemical attack.
 The breakdown reaction between the silver soldered
stainless steel joints is an electrochemical process with
no initial evidence of gross macroscopic corrosion.


 After a time, many silver – soldered joints
exhibit a change in appearance such as
darkening to resemble a tarnished – corroded
surface.
 Laboratory studies on corrosion indicate that
some of the precious metal substitutes may
corrode while in service.18


Soldering failures are seen due to variety of reasons-
 Failure to clean the parts to be joined.
 Improper fluxing
 Poor flow of solder
 Over heating of the solder can lead to pitted joint of
low strength.
 Besides porosities and brittleness from oxides, gases or
foreign matter resulting from the soldering procedures
are factors for increasing the incidence of failure of
soldered joints.
 Creep, corrosion, crack stress corrosion, fatigue and
corrosion erosion. Are other failures encountered


 Besides the deterioration of the soldered joints, concern
must also be given to the released – corroded agents.
 For cadmium containing solders, because of cadmium
toxicity, a continual appraisal must e made regarding
cadmium‟s fate biologically. The release of cadmium
from dental alloys has been the subject of several
reports.
 Even in case of such non – toxic elements as
zinc, copper, tin and silver, the introduction of higher
concentrations of these elements via soluble corrosion
products can alter their behavior. Causing biological
imbalances and further biologic consequences.
 It is believed that possible allergies to non – toxic
metals released from dental alloy may be formed.


 Metabolic and bacteriologic participation can also occur in response to
corroded metallic agents. Furthermore penetration & staining of hard
dental tissues due to the release of metallic ions from solder or any
biomaterial are definitely to be avoided.

 Laboratory tests indicate that silver – soldered stainless steel joints
degrade in a saliva substitute and the prepared solutions.

 Corrosion products containing oxides, hydroxides and chlorides of
zinc, copper and sodium can be easily identified. Silver is also attacked.
Besides the oral physiologic fluids, additional chemical agents contained
in mouth rinses & in toothpaste for oral antiseptics, need careful appraisal
for resistance to the degradation and corrosion of dental materials.

 Many commercial mouth rinses contain active chlorides & additional
components. The chlorides are known for their depassivating tendencies
of metallic materials.


 Dermatitis due to contact with nickel was first
reported at the end of nineteenth century in
1925. Nickel allergy is rarely written down
when filling out patient history prior to seeing
the dentist, even though so many dentist items
do contain nickel. Nickel has been used in
dentistry for more then eighty years in both
restorative work
(fillings, crowns, bridges, partial dentures) and
Orthodontic appliances (wires, bands, brackets
,etc).

 Nickel alloys have the special problem of being a common
allergen, with as many as 6% of the female population &
20% of the male population being sensitive to them.17
(CRAIG, O „BREIN,POWERS, Dental material properties &
manipulation, 6th edition, chapter 11 gold and non- precious
alloys, page 321)

 Patho - physiology of nickel allergy: it arises as a result of
two essential,stages: an induction phase, which primes and
senitize the immune system for an allergen, and the
elicitation phase, in which this response is triggered. As
such it is a type IV delayed hypersensitivity re
action involving a cell – mediated response.


Intraoral symptoms
 Stomatitis from mild to severe erythema
 Perioral rash
 Loss of taste or metallic taste
 Numbness
 Burning sensation
 Soreness at the side of tongue
 Angular chielitis
 Severe gingivitis in the absence of plaque
Extraoral symptoms
 Generalized urticaria
 Widespread eczema
 Flare-up of allergic dermatitis


 Diagnosis of nickel allergy
A dermatologist should confirm the diagnosis
by patch testing using 5 per cent nickel sulfate
in petroleum jelly. Other tests done are
Dimethylglyoxime spot test, Finger test.
 Preventive strategies
 Avoidance of nickel
 Antiperspirants


 Therapeutic strategies

 Oral doxepin (10–25 mg at night in adults)
 Steroids In adults prednisone in a single
morning dose of 40 to 60 mg can be prescribed
and tapered over 2 to 3 weeks, as symptoms
resolve.
 Binding agents and barrier creams ethylene
diamine tetra-acetic acid (ETDA)


 Tru- Chrome Solder And Flux,

 Formula No. 6 Silver Solder,

 Unitek Flux


Welding is the fusion of two pieces of similar
metal under pressure without the introduction of
third material. The metal must be softened by heat
as well as compressed to achieve this.
Or
It may also be defined as process of fusing two or
more metal parts through the application of
heat, pressure or both without using filler metal to
produce a localized union between two parts.
 Pioneer work in this field was done was Friel and
Mc Keag

Welds are made by passing an electric current
through the pieces to be joined which are
pressed together tightly. The resistance offered
by stainless steel to an electric current of high
ampereage generates enough heat to soften it.


 Electric transformer
 Copper electrodes
 Pressure mechanism
 Timing
The heat generated is calculated using the formula
H ∞ I2 RT

H = heat in joules
I = current in amperes
R = resistance in ohms
T = duration of current in seconds fig : showing circuit diagram of welder


 COLD WELDING – is done by hammering or
pressure. An example is cold welding of gold
foil filling.

 HOT WELDING – uses heat of sufficient
intensity to melt the metals being joined. The
heat source is usually an oxyacetylene flame or
high amperage electricity.


 SPOT WELDING

 PRESSURE WELDING

 LASER WELDING

 OXY-ACETYLENE (OA)

 ARCH WELDING

Typical values for the pulse are 2 to 6 volts for
1/25 – 1/50th of a second at 250 to 750 amperes.

Fig : a spot welder.


Spot welding may be used as method of fusing-

 Stainless steel strip for making bands.
 Securing attachments to the bands
 Attaching springs to a rigid bow wire, or to
bands.
 It is used more in the construction of fixed
appliances than removable appliances.


Gold foil, mat, or powdered gold) restorations
are pressure welded by hand or mechanical foil
condensers


A laser generates a coherent, high intensity impulse of
light that can b focused. By selecting the duration and
the intensity of impulse metals can be melted in small
regions without extensive micro structural damage to
the metal. Owing to the expansion from the local high
temperature and the change of state, the two liquid
surfaces contact and form a weld on solidification


oxy-acetylene flame burns at 6000 ͦF, and is the
only gas flame that is hot enough to melt all
commercial metals. Oxy-acetylene welding is
simple in concept - two pieces of metal are
brought together, and the touching edges are
melted by the flame with or without the
addition of filler rod.


Advantages of Oxy-Acetylene Welding :
 It's easy to learn.
 The equipment is cheaper than most other types of welding rigs
(e.g. TIG welding)
 The equipment is more portable than most other types of welding
rigs (e.g. TIG welding)
 OA equipment can also be used to "flame-cut" large pieces of
material.

Disadvantages of Oxy-Acetylene Welding :
 OA weld lines are much rougher in appearance than other kinds
of welds, and require more finishing if neatness is required.
 OA welds have large heat affected zones (areas around the weld
line that have had their mechanical properties adversely affected
by the welding process)


The fusing of two or more pieces of metal
together by using the heat produced from an
electric arc welding machine. The arc is like a
flame of intense heat that is generated as the
electrical current passes through a highly
resistant air gap.


 Wires should not be parallel to each other


 Instead the should be placed perpendicular to
each other in a groove.


Welding of stainless steel depends upon the proper
use of the following three variables-

 The current following through the circuit
 The time during which the current is allowed to
flow.
 The mechanical pressure applied at the welding
head.

The improper application of these variable may
result in under welding or over welding.


UNDER WELDING
 Insufficient time.
 Insufficient amount of time for which the current is
passed.
 Pressure applied is insufficient for approximation.

OVER WELDING
 Yields as weak joint as under welding
 Joint is more prone to corrosion
 This occurs when chromium is precipitated at the
grain boundary of each crystal. This process is
known as weld decay


“A satisfactorily welded joint is the one which is
strong, has not undergone
oxidation(blackening), and has not been over
compressed during fusion”


Strength of the welded joint
In engineering applications, spot and pressure
welds have strengths comparable to other forms of
joining metals such as soldering or arc welding.
Laser welds are comparable to soldered joints.
Corrosion resistance of the welded joint
welds in general are more susceptible to corrosion
than the surrounding metal. Spot welding in
dentistry has been confined to temporary
appliances, where the results have been
satisfactory.

 The welding surfaces should be free of all the debris and oxides.
 The surface of each electrode should be smooth, flat and
perpendicular to its long axis. Sparking and localized over
welding would result if the contact is not uniform.
 Adjust the welder to the setting recommended by the
manufacturer.
 Select the proper electrode of the proper thickness or shape of the
material to be welded. A broad electrode should be used for thin
material and a narrow electrode should be used for thick material.
This will allow sufficient heat to reach the weld area but not allow
oxidation of the material.
 If narrow electrode is used to weld a bracket (thick) to a
band(thin), localized over welding will occur in the thin material
and under welding will occur in the thick material.
 If sparking is observed, localized over welding has occurred. If
black areas are seen where the electrodes contacted the metal, over
welding has occurred


 Ozone is a highly active form of oxygen and can
cause great irritation to all mucous membranes.
Symptoms of ozone exposure include
headache, chest pain, and dryness of the upper
respiratory tract.
 Ultraviolet radiation (UV) is generated by the
electric arc in the welding process. Skin exposure
to UV can result in severe burns, in many cases
without prior warning.
 Exposure to infrared radiation (IR), produced by
the electric arc and other flame cutting equipment
may heat the skin surface and the tissues
immediately below the surface.


 Mount the electrodes correctly in the welder
and adjust with parallel precision to eliminate
gaps.
 Weld together the wires of same material
 Place the thinner wire in the groove of lower
electrode
 Use 1540 Newton of pressure
 Set the voltage according to the operator
instructions
 Use single electric impulse


 506- A DIAL- A – WELDrocky
mountain/denver,Colorado 80217

 Multi Purpose Orthodontic
Welderunitek, Monrovia, California 80217


 It‟s a term used industrially. Soldering operations
at and above 450° C is generally termed brazing.
Most dental soldering procedures are actually
brazing but the terms are used interchangeably in
dentistry.
 Brazing is defined as joining of metals by the
fusion of filler metal between them, at a
temperature below the solidus temperature of
metals being joined and above 450° C.
 The American National Standards Institute (ANSI)
currently is considering a proposal to call all
joining operations in dentistry as brazing rather
than soldering. Thus brazing may be the
predominant term in the future.

Electropolishing, also known as electrochemical
polishing or electrolytic polishing , is an
electrochemical process that removes material
from a metallic workpiece

PURPOSE OF ELECTROPLOSHING
Electropolishing improves corrosion resistance
by reducing surface area, eliminating
occlusions, reducing free iron, and producing a
passivating film of a corrosion resistant
chromium oxide.

Orthophosphoric acid 10-75%by vol

Sulfuric acid 25%by vol

Density at room temperature 1.74-1.82 g/cm3

Temperature 50-85°c

Voltage 8-20 V (power supply 20 Volt

Exposure time 0.5-30 min

The electropolishing process removes the nickel
and the iron preferentially, leaving a surface
rich in chromium. This phenomenon imparts
the important property of “passivation” to
electropolished surfaces.


welding soldering brazing

1 No third metal is introduced Third metal is introduced Third metal is introduced

2 Temperature required can Temperature required is upto 450° Temperature required is above
range up to 3800°C C 450° C

3 Work pieces are heated up to They are not heated upto melting Work pieces are heated but
their melting points point below their melting point

4 Mechanical properties may Change in mechanical properties of Change in mechanical
change of the metal due to the parent metal is negligible properties of the parent metal
such high temperatures that is negligible
are used.
5 High skill level is required Cost and skill involvement is low Both cost and skill level
involvement is in between the
two
6 No preheating is required Preheating is required if good Preheating is desirable.
quality joints are desired

 The choice of soldering materials has extreme
importance in determining the properties of the
soldered joints. In Orthodontics silver solders are
popular because of their low fusion temperature
and easy handling characteristics. It is also
rationalized that both removable and permanent
Orthodontic appliances are not meant to stay for
life, therefore solders with properties inferior to
high fusing solders can be tolerated.
 Soldering is still useful and needed procedure for
joining of metallic parts. The choice metal joining
procedure is in many instants up to the discretion
of the Orthodontist and the technician.


 Both soldering and welding can cause a
deterioration in properties if the wire is
overheated or under heated.
 In the final analysis, however the combination
of techniques which offer optimum
mechanical, physical and chemical properties
or offer desired properties which are most
favorable must be selected.
 Welding is the most commonly used procedure
by an Orthodontist. It is so common that it is
almost a reflex.


“ Nothing is good or bad in the world, our
perception makes it so, what seems like
congestion in the train becomes atmosphere in
the night club”


REFERENCES

 1. B.W.DARVELL, Materials Science For Dentistry, Chapter 22 soldering and welding, 9th edition, page 486.
 2. KENNETH J. ANUSAVICE & PAUL CASCONE, Chapter 19 Dental Casting And Soldering Alloys, Phillips‟ Science Of
Dental Materials 11th Edition, page 608,612,613,614,615,616
 3. STEPHEN T. RASMUSSEN, O‟BREIN & RYGE, an outline of dental materials & their selection, chapter 26 soldering
and welding, page 320,326,328
 4. CRAIG‟S DENTAL MATERIALS, chapter 15noble dental alloys and solders, page 378,379
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


Thank you….

Dr. Sneh Kalgotra
1st year post graduate student
Deptt. Of Orthodontics and Dentofacial Orthopaedics,
Govt. Dental College & Hospital, Srinagar


soldering and welding in orthodontics

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