Classification of provisional restoration
On the basis of method of fabrication
(ii) Custom-made restoration: Mainly made by direct technique or the
indirect technique or combination of both
On the basis of fabrication technique
(iii) Indirect–direct technique
On the basis of material used to fabricate
(i) Resin-based autopolymerizing and dual-cure resins (e.g. PMMA,
poly(ethyl methacrylate), bis-glycidyl methacrylate resins, bis-acryl
(ii) Metal-based (e.g. aluminium, stainless steel, tin–silver, nickel–
(i) Short-term temporary: For smaller time duration less than 2 weeks
(e.g. single crown, short-span bridges)
(ii) Long-term temporary: Longer time duration (between 2 weeks and
few months). This type includes periodontally compromised teeth,
in full mouth rehabilitation cases.
Custom-made provisional restoration
The custom-made provisional restorations are made by direct or
indirect technique or combination of both. Custom matrix is formed
to create the proximal and occlusal contours of the provisional
restoration. These are preferred for fabrication of multiple unit or
complex interim restorations. Usually, an elastomeric or alginate
overimpression is made on the diagnostic cast or in the mouth before
tooth preparation. This overimpression can then be used to fabricate
the provisional restoration. Elastomeric impression material provides
better stability than alginate, but because of the cost factor alginate is
most commonly used. Another method is to form a template on the
diagnostic cast with clear thermoplastic vacuum-formed resin
material. This template is filled with resin and applied on the
prepared teeth/tooth or check cast of the prepared teeth. Templates
are very stable and good acceptable provisional restoration is
A thin oversized, shell crown or bridge can be fabricated by
autopolymerizing resin through sprinkle-on method on the diagnostic
cast. This shell can also be heat cured in the laboratory. This shell is
loaded with resin and placed on the prepared tooth or cast of the
prepared tooth. Provisional restoration made can then be shaped to fit
Techniques used for fabrication of provisional
A number of techniques are available for fabricating provisional
restorations. The external contours of the provisional restoration are
formed by a matrix and the internal adaptation is formed by either
direct technique or the indirect technique.
A matrix is always required to form the external contours of the
provisional restoration. Matrix can be custom-made or prefabricated.
The prefabricated or preformed matrix is usually used for single unit
restoration. The internal adaptation is done with direct technique or
It is indicated for single crowns and short-span bridges. In this
technique, the matrix of choice is tried over the prepared teeth. The
matrix is formed from the preoperated diagnostic cast with preferred
material. After tooth preparation, the matrix is seated in the patient
mouth to check its fit. The prepared tooth is then isolated and
Vaseline is applied gently over the tooth surface. Next, the selected
material is mixed according to the manufacturer’s instructions and
loaded into the matrix. This loaded matrix is gently seated onto the
prepared tooth and allowed to set. The matrix should be moved in
and out in order to prevent interlocking of the resin onto the prepared
tooth. After the material has reached the rubbery stage, the
provisional restoration is carefully teased out and reseated several
times, till the polymerization is completed. The area needs to be
continuously flushed with water during the completion of this
procedure. This technique is not preferred these days because it has a
• Less material is consumed, as intermediate impression, etc. are
• There is a high chance of pulpal damage due to chemical irritation
• Exothermic reaction of resin may damage the pulp.
• There are chances of resin interlocking onto the prepared tooth.
• There is poor marginal integrity.
A sectional impression is made with elastomeric impression material
of the diagnostic cast or diagnostic wax-up to make the matrix. After
completion of tooth preparation, impression with preferred material is
made and is poured with dental plaster or stone. The matrix is then
tried on the cast to check its fit. The cast is coated with a separating
medium. Once the fit is satisfactory, the resin of choice is mixed
following the manufacturer’s instruction and is loaded onto the
matrix. The loaded matrix is placed on the cast and allowed to
polymerize. The matrix should be firmly seated onto the cast and can
be stabilized by elastic bands. The cast–matrix assembly can be placed
in warm water in a pressure pot to increase its density and strength.
• The material used does not polymerize in the mouth.
• The prepared tooth is not exposed to exothermic reaction of the
• There is no chemical irritation due to the free monomer onto the
• It can be used even in cases with complex fixed partial designs with
• Undercuts, if any, can be blocked on the cast for easy removal or
placement of the temporary bridge.
• Marginal fit is more accurate than the direct technique.
• It results in increased patient comfort.
• This technique is time-consuming.
• More material is required in the technique.
• It may require reline in the margin intraorally.
This technique combines both the above-mentioned techniques to
provide an accurately fitting provisional restoration. A thin shell in
the form of matrix is fabricated on the diagnostic cast. This thin shell
is tried on the prepared tooth and the appropriate resin material
(preferably light cure) is mixed and relined intraorally. After
polymerization, the provisional restoration is finished and polished in
FIGURE 27-1 Matrix is relined and cured using light-cure
• It provides best marginal accuracy.
• It is least damaging to the pulp.
• More time is needed for this technique.
Commonly available prefabricated crowns
Prefabricated or preformed crowns are available in variety of tooth
shapes and sizes and different materials. Their use is limited mostly to
the single crowns, as it is difficult to fabricate pontic for fixed partial
dentures. These crowns mostly require relining with
autopolymerizing resin or light-cure resin to achieve best fit and
Preformed or prefabricated crowns can be classified into the
following two groups on the basis of type of material used:
(i) Resin-based crowns (e.g. cellulose acetate, polycarbonate)
(ii) Metal-based anatomical crowns (e.g. aluminium, silver–tin, nickel–
Polycarbonate crowns (fig. 27-2)
• These are indicated for anterior single crown.
FIGURE 27-2 Polycarbonate crowns of different shapes,
• These are made of highly colour-stable resin.
• Aesthetics are similar to ceramic crown.
• These are supplied for use in the anterior incisors, canines and
• It is supplied only in one shade and requires a particular shade
relining resin to modify its shade.
• It may require extensive reshaping and recontouring to get a proper
• It may have sharp ledges or overhangs, if not contoured properly.
• It is often supplied as thin shells (0.2–0.3 mm) which act as matrix.
• It is available in various tooth shapes and sizes.
• It can be used in both anterior and posterior regions.
• Particular shade resin is loaded into the matrix and placed onto the
prepared tooth and allowed to polymerize.
• This thin shell does not bond to the resin chemically and
mechanically and, therefore, can be easily removed.
• The final provisional crown is then shaped, finished and polished.
Preformed or prefabricated anatomical metal
Prefabricated anatomical metal crowns are mostly indicated in the
posterior region which requires immediate coverage of the crown like
in cases of fractured molar tooth.
• It is used in the posterior regions only.
• It is supplied in the form of both anatomical crowns and nonanatomical
• Nonanatomical cylindrical shells are inexpensive but require
elaborate modification to achieve an acceptable fit.
• Anatomical crowns are mostly preferred.
• Preformed crowns should be modified outside on the swaging block
and not inside the patient mouth.
• In any case, the patient should be allowed to bite on unmodified
• This may even lead to fracture of the natural tooth.
• Although the crowns are more ductile and can easily be contoured
• Overhanging margin may irritate the gingiva.
• It is rigid, more durable and has high strength.
• It is indicated for damaged deciduous dentition and sometimes for
• The crowns are adapted using contouring and crimping pliers.
• These usually cannot be relined with resin material.
• These are luted with high-strength luting cement.
• It is usually used as long-term provisional restoration.
• Disadvantage: These are difficult to adapt and often do not produce
FIGURE 27-3 Nickel–chromium anatomic crowns.
Limitations of provisional restoration
Provisional restoration is fabricated to function for short duration of
time. It satisfies the functional and aesthetic requirement till the time
the definitive prosthesis is fabricated. However, it has limitations too.
• Lack of strength: Provisional restorations fracture in long-span
• It has poor marginal adaptation.
• Colour instability: This can occur, if the provisional restorations are
• Poor wear properties: Resin wears in the proximal contact area and
may result in drifting of the teeth.
• Detectable odour emission: As the resins are porous, bad odour is
• Inadequate bonding characteristics: Eugenol-based cements are
incompatible with methyl methacrylate resins, as these interfere in
• Indirect technique is preferred over direct technique to fabricate
provisional restoration for its accuracy and protection of pulp, in
• Prefabricated polycarbonate crowns are used on prepared single
• Bis-acryl composite resin should not be used in long-span bridges,
as these are brittle in nature.
Different Concepts of Occlusion in Fixed Prosthodontics, 393
Bilateral Balanced Occlusion, 394
Unilateral Balanced Occlusion or Group
Canine-Guided Occlusion or Mutually Protected
Occlusion or Organic Occlusion, 395
Functionally Generated Pathway, 396
Requirements before Using this Technique, 396
Role of Diagnostic Wax-Up, 397
Pros and Cons of Semi-Adjustable Articulators in Fixed Partial
Pros of Semi-Adjustable Articulators, 398
Cons of the Semi-Adjustable Articulators, 398
Fully Adjustable Articulators and their Utility in FPD with Multiple
Different Splints Used in Fixed
Myofascial Pain Dysfunction Syndrome, 400
Occlusal Therapy in Fixed Prosthodontics, 400
The maintenance of occlusal harmony is one of the most important
factors in determining the long-term success of fixed restorations. It is
important to understand different concepts of occlusion in fixed
prosthodontics in order to diagnose and treat occlusal disharmonies.
Different concepts of occlusion in fixed
There are three concepts or schemes of occlusion which are commonly
used in fixed restorations. These concepts are bilateral balanced
occlusion, unilateral balanced occlusion and mutually protected
1. Bilateral balanced occlusion
2. Unilateral balanced occlusion or group function
3. Mutually protected occlusion
These are described in brief below.
• Balanced occlusion is bilateral, simultaneous contact of all the teeth in
maximum intercuspation and during all eccentric movements of the
• This type of occlusion is ideal for fabrication of complete dentures, as
it improves the stability of dentures.
• This occlusal scheme helps to distribute lateral forces throughout
the teeth and condyles during mastication.
• It has both cross-tooth and cross-arch balance (Fig. 28-1).
• Balanced occlusion is based on three classic theories of occlusion:
Bonwill’s three points of occlusal balance, Spee’s curve of Spee and
Monson’s spherical theory of occlusion.
• At the start of the century, this type of occlusion was used in the
treatment of dentulous and edentulous patients.
• It was widely used by B.B. McCollum and E.R. Granger but was
criticized by H. Stallard and C.E. Stuart.
• Occlusal surface wears due to excessive contact area; it is thought to
• It is extremely difficult to find a balanced occlusion in the natural
dentition. It may be found in the cases of advanced attrition.
FIGURE 28-1 Bilateral balanced occlusion.
Unilateral balanced occlusion or group
• Clyde Schuyler (1929) advocated the group function occlusion.
• This type of occlusion occurs with all the teeth contacting only on
the working side with no contact on the balancing side (Fig. 28-2).
• This occlusion has been frequently observed in natural dentition.
FIGURE 28-2 Unilateral balanced occlusion or group
function. Simultaneous contact occurs on the canine and
posterior teeth on the working side during lateral movement.
H.L. Beyron (1969) listed the characteristics of this type of occlusion:
• Teeth should receive stress along their long axis.
• Total stress should be distributed among the tooth segment in
• No interferences occur from closure into intercuspal position.
• Keep proper interocclusal clearance.
• Teeth contact in lateral movement without interferences.
Characteristics of group function occlusion
The characteristics of group function occlusion include:
• Theory of long centric: Long centric is a 0.5–0.75 mm free space
between maximum intercuspation and centric relation position
without changing vertical dimension of occlusion.
• It follows concept of all working side teeth sharing lateral pressures
• It follows concept of nonworking side teeth free from contacts
• Group function does not have harmful effects as seen with a
balanced occlusion and is not difficult to fabricate.
• Group function has been advocated by Mann and L.D. Pankey for
• The functionally generated path technique described by F.S.
Meyer is based on group function.
Canine-guided occlusion or mutually
protected occlusion or organic
• This concept originated from the work of A. D’Amico, C.E. Stuart,
H. Stallard, C.E. Stuart and V.O. Lucia.
• This is one of the most widely used occlusal schemes because of ease
of fabrication and greater acceptability by the patient.
‘An occlusal scheme in which the anterior teeth disengage the posterior teeth
in all mandibular excursive movements, and the posterior teeth prevent
excessive contact of the anterior teeth in maximum intercuspation’. (GPT 8th
• It is found in patients with good periodontal health and minimal
wear such that anterior teeth prevented the posterior teeth from
making any contact during mandibular excursions on the working
or the nonworking sides (Fig. 28-3).
• This separation from occlusion is also called disocclusion.
• According to GPT, disocclusion is defined as ‘separation of opposing
teeth during eccentric movements of the mandible’.
• In the position of maximum intercuspation, the posterior teeth
occlude with the forces being directed along the long axis of the
teeth and the anterior teeth have minimal or no contact.
• Thus, the anterior teeth protect the posterior teeth and the posterior
teeth protect the anterior teeth from the obliquely directed forces.
• This type of occlusion is, therefore, known as the mutually protected
occlusion and is advocated for full mouth rehabilitation provided the
teeth are periodontally healthy.
• In cases where there is anterior bone loss or missing canines, group
function should be the occlusion scheme of choice for restoration of
• The mutually protected occlusion cannot be used in class II, class III
or crossbite cases, where the mandible cannot be guided by the
FIGURE 28-3 Canine-guided occlusion.
movements of both the TMJs. There are two types of movement
occurring in the TMJ, namely, rotational and translational.
Rotational movement: Movement of body about an axis
Translational movement: Movement of all the points in the body with
Movement of the mandible occurs around three axes:
1. Horizontal axis: Movement occurs in a sagittal plane when
mandible makes a purely rotational opening and closing movement
around the terminal hinge axis passing through both the condyles.
This type of movement is called a hinge movement. This type of
movement occurs till about 20–25 mm of separation in the anterior
teeth and beyond it translatory movement occurs.
2. Vertical axis: Movement occurs in horizontal plane when the jaw
moves laterally to one side. Condyle moving to one side is called the
working side condyle and the opposing condyle is called the
nonworking side or balancing condyle. The working side condyle
moves anteriorly out of the terminal hinge position and the balancing
condyle rotates around the terminal hinge position. This bodily shift
of the working side condyle is called the Bennett movement.
3. Sagittal axis: Movement occurs in the frontal plane when the
mandible moves laterally. The nonworking or balancing condyle
moves down and medially, whereas the working condyle rotates
around the sagittal axis perpendicular to this plane.
U. Posselt (1957) first described the extremes of the mandibular
movements and called them border movements.
Factors affecting mandibular movements are:
Determinants of mandibular movement (also see chapter 5)
Anterior determinants: Teeth are the anterior determinants which guide
the mandible in various excursive movements. Anterior teeth
provide the incisal guidance, i.e. the overjet and overbite.
Posterior determinants: It is the condylar guidance which is influenced
by the slope of articular eminence.
Functionally generated pathway
Functionally generated path is defined as ‘registration of the paths of
movement of the occlusal surfaces of teeth or occlusion rims of one dental
arch in plastic or other media attached to the teeth or occlusal rims of the
• This technique was first described by F.S. Meyer (1934).
• In this technique, a soft plastic material, such as wax, is used to
carve the pathways travelled by opposing cusps on lateral excusive
• This record of static and dynamic occlusion is made in the patient’s
mouth and reduces the role of articulator as a simple hinge
• This technique is indicated for single-tooth restorations only.
Requirements before using this technique
• It is used for single restorations.
• There should be no posterior interferences.
• There should be no missing or damaged opposing teeth.
• Technique is simple, if well versed.
• Soft plastic material such as wax or pattern resin is adapted over the
• The patient is asked to bite in intercuspal position and move the jaw
• The cusp tips carve grooves on the wax which represent the border
movements of the mandible in three dimensions.
• This impression is then cast in the mouth by painting plaster or
• This stone functional core is then used to fabricate posterior tooth
• The cast is then mounted in the laboratory and used in conjugation
with the normal opposing model.
• This functional core indicates not only the cusp tips of the opposing
teeth in intercuspal position but also where these move relative to
the proposed crown. This is a static record of the patient’s dynamic
Diagnostic wax-up is a process in which correctly mounted and then
important diagnostic tool which should be fabricated by the
technician under the guidance of clinician.
The features of diagnostic wax-up are:
• It is a valuable guide to the treatment objective for both the clinician
• It provides information related to the occlusal scheme which is to be
• It provides the patient with an opportunity to visualize the outcome
• It provides the template for provisional restorations.
• It provides information about the need for crown lengthening and
• It acts as a guide for optimum crown preparation.
• It helps in creating an occlusal plane.
Role of articulators in fixed prosthodontics
An articulator is a mechanical device which represents the TMJ and
simulates some or all the mandibular movements. The main principle
of articulator is to replicate the movements of TMJ as closely as
• It maintains casts at an established vertical height and centric
relation and simulates the mandibular movements as closely as
• These are classified on the basis of accuracy in reproducing
• These can be nonadjustable, semi-adjustable and fully adjustable
• The upper and lower casts are attached to the articulator to study
the functional and parafunctional relation between the teeth for
diagnosis, occlusal rehabilitation and equilibration.
• These are also used to accurately fabricate fixed and removable
prosthesis which are in harmony with various mandibular
• Articulator is used to establish occlusion in maxillofacial prosthesis
and for fabrication of occlusal splints.
• It is used for functional analysis of occlusion.
• It is used for full mouth rehabilitation.
• No articulator can reproduce the mandibular movements exactly.
Selection of the articulator depends on the complexity of restorative
Pros and cons of semi-adjustable
articulators in fixed partial denture
Pros of semi-adjustable articulators
• Use of this instrument does not require more time or expertise.
• These are capable of accepting lateral and protrusive records.
• Arcon-type semi-adjustable articulators are usually used in fixed
• Use of this articulator reduces adjustments during try-in and
• This articulator has same spatial dimension as the condyle to the
teeth and, therefore, the discrepancies between the radius of
movement of articulator and the arc of tooth closure are minimal.
• One advantage of this articulator over nonadjustable is that it can be
adapted to the patient’s specific condylar movements.
• This type of articulator is used for fabrication of single crowns and
fixed partial dentures (FPDs).
• Arbitrary facebows are used with semi-adjustable articulators.
• Some articulators can allow adjustments to condylar inclinations
and progressive or immediate side shift.
Cons of the semi-adjustable articulators
• Intercondylar distance is not fully adjustable, as it can be adjusted to
small, medium or large configurations in some instruments.
• All the border movements are not reproducible.
• Some articulators reproduce the condylar path as a straight line
• These are more time-consuming and more expensive than the
Fully adjustable articulators and their
utility in FPD with multiple abutments
Fully adjustable articulators are considered to be the most accurate
instruments which are capable of accepting three-dimensional
• These can reproduce an entire range of border movements of the
• Accuracy and reproduction are highly dependent on the skill of the
• Here, pantographic tracings are used to record the border
movements in the form of series of tracings.
• The intercondylar distance is completely adjustable.
• Kinematic facebow is used to locate true hinge axis.
• The ability of the articulator to track irregular pathways of the
mandible allows for fabrication of restorations of multiple
abutments. This is especially useful in full mouth rehabilitation
• Correct use of this articulator can reduce the chairside time during
try-in and insertion of the prosthesis.
• Although not required in general practice, their use become more
sensible when complex prosthesis are fabricated, especially in cases
where atypical mandibular movement exists.
Pathological occlusion is defined as ‘an occlusal relationship capable of
producing pathologic changes in the stomatognathic system’. (GPT 8th Ed)
In pathological occlusion, disharmony between the teeth and the
TMJ exists resulting in signs and symptoms that require treatment or
intervention. The stomatognathic system consists of teeth,
periodontium, muscles and the TMJ. In a pathological occlusion, one
or more aspect of the system is affected.
In pathologic occlusion, the common signs and symptoms noticed
• The teeth may show hypermobility, open contacts or abnormal
• Parafunctional habits, such as bruxism or clenching, may show
abnormal tooth wear, cuspal fracture or chipping of the incisal
• There could be trauma from normal occlusion when the periodontal
status of the teeth is compromised.
• Acute or chronic muscular pain on palpation may indicate habits
related to psychic tension, such as bruxism or clenching.
• Chronic muscular fatigue can lead to muscular spasm or pain.
• Pain, clicking sound or popping sound in the TMJ can indicate
• Clicking of the joints may indicate internal derangement of the
The acute signs and symptoms of the patient should be addressed
first and should be relieved. It is important to select an occlusal
scheme which prevents the recurrence of the signs and symptoms of
the pathological occlusion. An optimum occlusion should be provided
so that the patient requires minimum adaptation to the new occlusal
‘A rigid or flexible material used to protect, immobilize, or restrict motion in
• Mobility is reduced drastically.
• Forces are distributed to a number of teeth.
• Food impaction is prevented and proximal contacts are stabilized.
• Migration and overeruption is prevented.
• Discomfort or pain is eliminated.
Splints can be of two types, namely, temporary splints and permanent
Different splints used in fixed prosthodontics
• It is used in management of bruxism and clenching.
• It is made over the occlusal surfaces of the teeth with heat-cured
• It can be fabricated for one or both the jaws depending on the
availability of freeway space.
• Most commonly, it is fabricated in the upper jaw.
• If it is used in one jaw, the occlusal contact of the opposing jaw is
adjusted, so that there is smooth maximal contact in gliding
• The acrylic resin should extend just below the height of contour for
ease of insertion and removal and retention.
• It is used in management of TMJ disorders and bruxism.
• It has been found to be effective in controlling myofascial pain.
• The patient is given a new occlusal scheme made in acrylic resin
• The patient is asked to wear the splint for certain duration of time.
• If the patient adapts well and becomes comfortable over a period of
time, the proposed restorative treatment is likely to be successful.
• It is an important diagnostic procedure before treating cases
requiring full mouth rehabilitation.
Cast metal resin-bonded FPDs or maryland
• It is used with intact or very slight alteration of enamel.
• This type of prosthesis is functional, aesthetic, reversible and
• It consists of a metal frame bonded with resin cement to the tooth
• Although more successful in the anterior region, it can also be used
Myofascial pain dysfunction syndrome
Myofacial pain is a type of regional muscular pain which is
characterized by localized areas of firm, hypersensitive muscular
bands of tissues called the trigger points.
Causes: Local and systemic factors, such as trauma,
hypervitaminosis, viral infection, muscle fatigue and emotional stress.
Signs and symptoms of myofascial pain dysfunction syndrome
• Unilateral dull pain in the ear/periauricular area which radiates to
the angle of mandible, temporal area. Pain is relatively constant and
usually reported as worse in the morning.
• Tenderness over the neck of the mandible in region distal to the
tuberosity. Area of tenderness is presumed to be the spasm area of
• Clicking or popping sound over TMJ. If only this symptom is
present, the patient is not included in MPDS.
• Limited jaw movement: Fourth cardinal symptom of MPDS. It is
characterized by the inability to open the mouth widely or there is
deviation while opening the mouth.
One of the primary objectives of restorative dentistry is to restore and
replace teeth in harmony with TMJs. If the teeth are not in harmony
with the joints and mandibular movements, it is understood that there
is some occlusal interference.
Occlusal interference can occur in the following:
• On the working side when mandible makes lateral
• On the nonworking side when mandible makes
• When occlusal interference occurs, occlusal therapy
• To direct the occlusal forces along the long axis of the teeth
• To have centric relation coincide with maximum intercuspation
• To have simultaneous contact of the teeth in centric relation
• In protrusive contact, there should be disocclusion of the posterior
• To attain the occlusal scheme selected for the patient (canine guided
• Physiological plane of occlusion
• A functional incisal guidance, i.e. proper overjet and overbite of the
• An aesthetic and phonetic relationship of anterior teeth
Occlusal therapy can include treatment, such as orthodontic
treatment for tooth movement, selective grinding or restoration or
replacement of missing teeth. Proper diagnostic aids are very useful in
providing proper occlusal treatment. Diagnostic wax-up on the
mounted diagnostic casts at established vertical dimension is the
fundamental guide for providing a suitable restorative treatment.
• Group function is characterized by contact of all teeth on the
working side and no contact on the balancing side during lateral
• Maximum limit of transverse hinge axis movement is 18–22 mm.
• In natural occlusion, the centric relation position is located 0.5–1.0
mm posterior to the centric occlusion position.
• The point at which the maximum opening of the jaws occurs
without translation movement of the condyle is called terminal
• Mutually protected occlusion or canine-guided occlusion is
characterized by posterior teeth protecting the anterior teeth in
intercuspal position and anterior teeth protecting the posterior teeth
• Arcon articulators are preferred for fixed prosthodontics because of
accuracy and ease during occlusal waxing.
• Pantographic tracings are used with fully adjustable articulators.
• Functionally generated path technique was first advocated by F.S.
• The most important factor in the success of the artificial crown is
restoration of proper occlusion.
Laboratory procedures in fixed
Dies and Various Materials Used for Making Dies, 402
Requirements of a Die Used in Fixed
Materials Used for Fabricating a Die, 403
Alloy and Historical Perspective of Dental Casting Alloy, 406
Historical Perspective of Dental Casting
History of Dental Casting Alloys, 406
Classification of Dental Casting Alloys and
Critical Evaluation of Precious, Semiprecious
and Nonprecious Alloys in Prosthodontics, 407
Casting Techniques for Casting of Base Metal
Casting Defects and their Remedies, 409
Investment Materials Used in Fixed
Shade Selection for the Patient Requiring FPD, 412
Characteristics of Colour, 412
Procedure of Shade Selection, 413
Dentist–Technician Inter-Relationship—Important Key to Success in
Guidelines for Technician, 413
Accurately fitting casting is important for successful fixed prosthesis.
To obtain precisely fitting casting, knowledge of various laboratory
procedures involved in fixed prosthodontics is critical. The
procedures are briefly explained in this chapter.
Dies and various materials used for
A die is defined as ‘the positive reproduction of the form of a prepared tooth
in any suitable substance’. (GPT 8th Ed)
Requirements of a die used in fixed prosthesis
• It should reproduce the prepared tooth accurately.
• Prepared surfaces and unprepared surfaces should be recorded
• It should be easily mounted onto the articulator.
• It should be resistant to abrasion.
• It should have adequate strength.
• It should reproduce details accurately.
• It should be easily wetted by wax.
• It should not stick with wax and should be available in colour
Materials used for fabricating a die
• Type IV and type V gypsum products are usually used as die
• These are capable of reproducing a 20-micron wide line according to
American Dental Association (ADA) (specification no. 19).
• They have poor resistance to abrasion which is overcome by using
gypsum hardeners (e.g. colloidal silica).
• The surface of the die can also be impregnated with low-viscosity
• The resins that are commonly used as die materials are epoxy resins
• Epoxy resins are cured at room temperature and are dimensionally
• It has very good abrasion resistance.
• It is more expensive than die stone.
• It undergoes some shrinkage during polymerization.
• Prosthesis fabricated on resin dies fits more tightly.
• It is not compatible with materials such as polysulphides and
• It is a time-consuming, complex procedure.
• Electroplated dies are used to provide good abrasion resistance and
• It involves the deposition of a coat of pure silver or graphite.
• A layer of pure metal is deposited on the impression and is
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