• In the absence of mesiodistal cusps, only the buccolingual cusps
were considered as a factor for balanced occlusion.
• In cases with a shallow overbite, the cuspal angle should be reduced
to balance the incisal guidance.
• This is done because the jaw separation will be less in cases with
• In cases with deep bite (steep incisal guidance), the jaw separation is
• Teeth with high cuspal inclines are required in these cases to
produce posterior contact during protrusion.
• Commonly used posterior teeth are those with cuspal inclination of
• Although the effective final height of the cusp depends on
inclination of the teeth, incisal guidance, condylar guidance, height
of the occlusal plane and the compensating curve, 33° posterior
teeth are best suited for balanced occlusion.
• It is a valuable factor as it allows the dentist to alter the cusp height
without changing the form of the teeth.
• The height of the cusp can be varied by inclining the long axis of the
• In cases of cuspless teeth, compensating curve can be used to
produce the equivalent of the cusp.
• Compensating curve is determined by the inclination of the
posterior teeth and their vertical relationship to the occlusal plane.
• Steeper condylar path requires a steeper compensating curve to
Compensating curve is defined as ‘the anteroposterior curving (in the
median plane) and the mediolateral curving (in the frontal plane) within the
alignment of the occluding surfaces and the incisal edges of the artificial teeth
that is used to develop balanced occlusion’. (GPT 8th Ed)
‘The anteroposterior and the lateral curvature in the alignment of the
occluding surfaces and incisal edges of the artificial teeth that is used to
develop balanced articulation’.
• To provide balancing occlusal contacts for the protrusive
• To aid in compensating for steep condylar inclination
The curve of Spee, the curve of Wilson and the curve of Monson are
associated with the natural dentition. These curves are incorporated in
the complete dentures in order to produce balanced occlusion.
It is defined as ‘the anatomic curvature established by the occlusal
alignment of the teeth, as projected onto the median plane, beginning with the
cusp tip of the mandibular canine and following the buccal cusp tips of the
premolar and the molar teeth, continuing through the anterior border of the
mandibular ramus, ending with the anterior most portion of the mandibular
• This curve was first described by Ferdinand Graf Spee in 1890.
• It is found in natural dentition and is reproduced in complete
dentures to enhance stability (Fig. 8-14).
• There will be contact of the posterior teeth during protrusion.
• If this curve is not followed, there will be disocclusion of the
posterior teeth during protrusion (Christensen’s phenomenon).
FIGURE 8-14 Anteroposterior curve – curve of Spee.
It is defined as ‘the curve of occlusion in which each cusp and incisal edge
touches or conforms to a segment of the surface of a sphere 8 inches in
diameter with its centre in the region of the glabella’. (GPT 8th Ed)
• It was first described by George S. Monson (1869–1933).
• The curve usually does not exceed 5–10° from the horizontal plane
of orientation when viewed from the frontal plane.
• It has concavity facing upwards.
• The curve touches the palatal and buccal cusp of the maxillary
• During lateral movement, on the working side, the mandibular
lingual cusp slides along the inner inclines of the maxillary buccal
cusp and on the balancing side, the mandibular buccal cusp would
contact the maxillary palatal cusp to provide lateral balance.
• It is defined as ‘the curvature in the lower arch af ected by the equal
lingual inclination of the right and left molars so that the tip points of the
corresponding cross-aligned cusps can be placed into the circumference of
the circle. The curve in the lower arch being concave and the one in the
• It was first described by G.H. Wilson (1911).
• First premolars are arranged according to this curve such that they do
not produce interference during lateral movements.
• It is also called frequency curve, probability curve, reverse curve or
• It is defined as ‘a helicoid curve of occlusion that, when viewed in the
frontal plane, conforms to a curve that is convex from the superior view,
except for the last molars which reverse that pattern’.
• It was first described by Max Pleasure (1937).
• He modified the occlusal surfaces of the lower posterior teeth to a
reverse curve by tilting the tooth buccally.
• This did not provide balancing contact in either protrusive or lateral
• Later this scheme was modified to provide the balancing contacts.
• The reverse curve was set in the premolars, flat occlusal surface on the
first molar, and a Monson curve at the second molar was arranged to
provide balanced contacts in lateral excursions.
• The distal of the second molar is elevated to produce the
compensating curve for the protrusive balance.
• The reverse curve, i.e. tilting of the occlusal surfaces buccally is done
in order to direct the forces of occlusion lingually to favour the
stability of the lower denture.
• C.H. Moses (1954) suggested that Pleasure curve was desirable in all
the patients except in those where the maxillary denture is insecure
because of the size or character of the basal seat.
Anatomic teeth are defined as ‘teeth that have prominent cusps on the
masticating surfaces and that are designed to articulate with the teeth of the
opposing natural or prosthetic dentition’. (GPT 8th Ed)
Anatomic teeth have 33° cusp angle. Cusp angle is measured as the
angle formed by the incline of the mesiobuccal cusp of the lower first
molar with the horizontal plane.
FIGURE 8-19 Cuspless or nonanatomic teeth.
Nonanatomic teeth or cuspless teeth are defined as ‘artificial teeth with
occlusal surfaces that are not anatomically formed’. (GPT 8th Ed)
Zero-degree teeth are defined as ‘posterior denture teeth having 0°
cuspal angles in relation to the plane established by the horizontal occlusal
surface of the tooth’. (GPT 8th Ed)
• Farrar appliance is a type of occlusal device which is used to
position the mandible anteriorly to treat temporomandibular joint
• Condylar guidance of the patient is determined by a protrusive
• ‘S’ shaped path of the glenoid fossa determines the path of
movement of the condyle and determines the condylar guidance.
• In the natural dentition, the centric occlusion is usually 0.5–1 mm
anterior to the centric relation.
• Concept of lingualized occlusion was proposed by Gysi in 1927, in
which the maxillary lingual cusp was used as the dominant element
which occluded against the corresponding position of the
• Reverse articulation is the occlusal relationship in which the
maxillary buccal cusps are placed in the central fossae of the
• Steep inclines are undesirable in complete dentures, as they
decrease the stability of the denture by increasing the inclined
• In resorbed ridges, the occlusal plane is placed closer to the ridge in
order to reduce leverage forces on the denture.
• Surfaces of the dentures that affect stability of the dentures are the
occlusal, impression and polished surfaces of the denture.
• Flat or zero incisal guidance provides maximum denture stability.
• Two end factors controlling protrusive movement in the complete
denture patients are incisal guidance and the condylar guidance.
• In long centric, there is freedom of movement up to 1 mm in the
sagittal and horizontal direction.
• Mutually protected occlusion is an occlusal scheme in which the
posterior teeth prevent excessive contact of the anterior teeth in
maximum intercuspation and the anterior teeth disengages the
posterior teeth in all mandibular excursive movements.
Waxing Procedure for Maxillary Trial
Wax-Up Procedure for Mandibular Trial
Procedures Followed During the Try-In
Deflasking of the Denture, 173
Laboratory Remount Procedure, 173
Rules for Selective Grinding, 173
Finishing and Polishing of Complete Dentures, 174
Waxing is defined as ‘the contouring of a wax pattern or the wax base of a
trial denture into desired form’. (GPT 1st Ed)
Waxing-up is defined as ‘the contouring of a pattern in wax generally
applied to the shaping in wax of the contours of a trial denture’. (GPT 1st
• Wax-up should duplicate the soft tissues as closely as possible.
• Contours of the denture flanges should be compatible with the
• Contours of the lingual flange should be compatible with the
tongue. It should have least possible amount of bulk, except at the
• Palatal section of the maxillary denture should accurately reproduce
• Notches should be provided to accommodate the frenum in both
• Borders, both labial and lingual, should fill the vestibule.
Methods of Waxing-Up the Trial Dentures
(i) Free hand or conventional method
(ii) Physiological or flange method
Waxing procedure for maxillary trial denture
• The thickness of the denture flanges and the borders are reduced or
built-up to desired dimension dictated by the final impression.
• Wax is contoured just above the cervical end of the tooth to produce
the gingival bulge or fullness simulating the attached gingiva.
• Wax is contoured around the cervical margin of the tooth at 30–40°
angulation with the long axis of the crown for anterior teeth and 45°
angulation for the posterior teeth.
• Wax is contoured above the canine to simulate the canine eminence.
• Root portion of the anterior teeth is carved in a triangular manner
with the canine root being the longest followed by the central
incisor and the lateral incisor.
• The contour of the anterior trial denture should have slight convex
• Gingival bulge area is almost nonexistent in the first premolar region
and progressively becomes more prominent in the second premolar
• Long and pointed interdental papillae are carved for the young
patient, whereas short and blunt papillae are carved for old.
• Stippling can be accomplished using a modified bristle brush in the
region of attached gingiva (Fig. 9-1).
• Stippling contributes to the natural appearance by reducing even
light refraction and by blending contours.
• Palatal surface is waxed to restore contours present before the loss
of teeth and supporting structures.
• Thickness of the palate should not be less than 1.5–2.0 mm in any
area. Any added thickness can alter the proper formation of speech
• The lingual contours of the upper central incisors are re-established
in the waxing procedures. This contour aids in phonetics and
provides natural feel to the patient’s tongue.
• Vault form of the denture depends on the vault form of the maxillae.
It is modified by the absorption of the bone and tissue as the result
of loss of teeth and supporting structures.
• Lingual festooning can be accomplished by restoring part of the
lingual surface of the tooth that is not supplied in the artificial teeth.
FIGURE 9-1 Stippling is accomplished using modified brush.
Wax-up procedure for mandibular trial denture
• The shape of the polished surface of the mandibular denture is
extremely critical in promoting stability of the denture.
• Buccal and lingual surfaces of the external denture surface should
slope towards the teeth to allow the tongue and cheeks to lie in rest
position and aid in retention of the denture (Fig. 9-2).
• The lingual flanges of the mandibular denture are waxed from the
posterior teeth to the peripheral roll to produce an inclined plane
that slopes towards the tongue.
• The lingual flange should have least amount of bulk, except at the
• This thickness is below the narrower portion of the tongue and it
greatly enhances the seal of the denture.
• The free gingival margin, gingival bulge and the interproximal
papilla are contoured similarly to the maxillary trial denture.
• The buccal surface of the mandibular dentures in the first premolar
region should be carefully shaped so that it does not interfere with
• Softened and tempered wax on the lingual flange can be moulded
by instructing the patient to swallow forcibly, grin broadly, pucker
the lips, read aloud for a few minutes and doing other oral and lip
• Interproximal area should be full bodied and convex, mesiodistally
• Carving of the wax is followed by polishing. Before polishing, it
should be ensured that any excess wax is removed, especially over
the tooth surface. Wax is smoothened by gently flaming using
alcohol torch, followed by cooling in chilled water.
FIGURE 9-2 Buccal and lingual surfaces should slope
towards the teeth for better stability.
Wax try-in is defined as ‘the process of placing a trial denture in the
patient mouth for evaluation’. (GPT 8th Ed)
• Rationale for wax try-in is to compare the general tooth and arch
position with that which might have been present during the
• Relationship of the mandibular and maxillary teeth is checked with
• The interocclusal distance is verified.
• Fit and extension of the denture are checked.
• Underextension and overextension are checked.
• Stability of the trial denture should be checked during this stage.
• Jaw relation records are verified.
• Aesthetics and phonetics are verified.
Procedures followed during the try-in stage
Verification of jaw relation records
• Both the recording bases should accurately fit into the patient’s
• First the mandibular denture should be inserted followed by the
• The patient is instructed to close the mouth lightly.
• If the denture border causes binding of the frenum, the labial notch
• The vertical dimension at rest and occlusion is assessed.
• Discrepancy in the occlusion, if any, is observed.
• New centric relation record is made and the lower denture is
mounted with the new interocclusal record.
Centric relation can be verified by the following methods:
(i) Intraoral observation of the intercuspation: If the teeth slide over each
other or if some tooth/teeth prevent others to intercuspate during first
contact, then discrepancy exists in centric relation position and new
(ii) Intraoral intraocclusal records: Posterior teeth are removed from the
lower denture. The lower occlusal rim is placed in the patient’s mouth
and he/she is instructed to close in the interocclusal record. This
record is verified on the articulator.
(iii) Extraoral articulator method: Centric relation is checked and verified
on the articulator rather than in the mouth. The centric relation record
is made by placing soft wax between the opposing teeth. This record
is placed in mouth to verify its accuracy. The purpose is to determine
whether the position of the teeth on the articulator is same as that in
• When the trial dentures are placed in mouth, the vertical dimension of
• Appearance of the patient’s face (whether relaxed or strained)
suggests whether there are any alterations in the vertical dimension.
• Lip fullness and visibility of the teeth are assessed as the patient
• The deepening of nasolabial sulcus, mentolabial sulcus and shape of the
• Positioning of the teeth is assessed by instructing the patient to
Orientation of the occlusal plane
• Plane of occlusion is checked for proper orientation.
• It should be parallel to the ala–tragus line.
• Position of the anterior teeth and the retromolar pad is used as
anterior and posterior landmarks, respectively, to assess the plane
Changes in tooth colour and translucency
• Characterization of the teeth according to the patient’s age, sex and
personality is assessed at this stage.
• The tooth colour, wearing, etc. are assessed for harmony between
the teeth and the patient’s face.
Establishing posterior palatal seal
• Posterior border of the denture is determined in the mouth and its
location is transferred on the cast.
• A T-burnisher or mouth mirror is used to locate the hamular
• The location of the right and left hamular notches is marked using
• As the patient says ‘ah’, the vibrating line is marked with the pencil.
• This marking is transferred on the trial denture base when the same
is inserted in patient’s mouth and the excess of base plate is
• The trial denture base is placed on the cast and bead on the cast is
• Groove on the cast is 1 mm high and 1 mm wide and sharp at its
apex which will be transferred as bead on the denture.
Flasking is defined as ‘the process of investing a cast and a wax replica of
the desired form in a flask preparatory to mould the restorative material into
the desired product’. (GPT 8th Ed)
Flasking is a laboratory procedure for making a two-sectional
This procedure applies to both maxillary and mandibular dentures.
Preparation of cast before flasking
• The bottom of the cast is lubricated with petrolatum jelly. This is to
ensure that the cast is accurately repositioned during the remount
• Cast and the waxed denture are soaked in water for few minutes
and then painted with gypsum separating medium.
• The lower half of the flask is invested first.
• The cast is centred into the flask.
• Use mixture of dental plaster for investment.
• Any undercuts should be removed in the investment, as they will
prevent the separation of the upper and lower flask after wax
• Investment is allowed to set.
• Separating medium is applied on the investment in the lower half of
• The ring portion of the flask is positioned over the lower flask.
• Second pour of dental plaster and stone are mixed.
• The mix is carefully poured over the teeth such that occlusal
surfaces and the incisal edges of the teeth are exposed.
• Investment is allowed to set.
• Once again the separating medium is applied to the ring portion of
• Third pour of dental plaster and stone are mixed.
• This is poured over the ring and the top of the flask is positioned
Wax elimination or boil out is defined as ‘removal of wax from a mould,
usually by heat’. (GPT 8th Ed)
• Once the stone and plaster mix used in flasking are completely set
(approximately 45 min), the wax elimination procedure is initiated.
• The flask is placed in clean boiling water on a flask holder for 5 min
• Remove the flask from the water and gently open it.
• Insert an instrument between the upper and lower halves and
• The softened wax and temporary denture base are removed
• The teeth should remain in the top half of the flask; any loose tooth
• Flush out all the remaining wax with clean boiling water.
• Saturate a piece of cotton with wax solvent and apply it around the
• Detergent can be added to remove any wax residue not removed by
• The mould is flushed again with boiling water to remove traces of
• It should be ensured that all the wax residues are removed, as
acrylic resin will not adhere to the surface coated with wax.
• The loose tooth is washed with boiling water and cemented into
correct position using cement.
• If palatal relief is indicated, tinfoil can be used to fit the outline of
• The mould surface is painted with liquid-separating medium to
prevent the surface from absorbing the liquid resin monomer.
• When the mould is still warm, the separating medium is painted.
• Allow the first coat to dry and then second coat is applied.
• This should result in a smooth, shiny mould surface.
• Allow the flasks to cool to room temperature.
Packing is defined as ‘the act of filling a mould’.
Denture resin packing is defined as ‘filling and pressing a denture base
material into a mould within a refractory flask’. (GPT 8th Ed)
• Monomer and polymer are mixed according to the manufacturer’s
• Polymer-to-monomer ratio is approximately 3:1 by volume and 2:1 by
• For an average-sized denture, usually 30 g polymer and 10 mL
• When the mix is in the dough stage, it is packed into the mould.
• The solubility of polymer into monomer and the size of the polymer
particles influence the dough forming time.
• The mixed dough is packed in the upper half of the flask in one
direction to avoid trapping of air into the mould.
• Enough material is packed to ensure overpacking on the first
• Wet plastic sheet is placed over the acrylic resin.
• The lower half of the flask is secured in position using hand
• Flask is placed in a bench press and closed slowly to ensure
complete flow of excess acrylic resin.
• Flask is removed from the press and carefully opened.
• Trial closure is done till all the excess materials are removed.
• In the final opening, the lower part of the mould is coated with
• The two halves of the flask are secured in position, such that there is
complete contact of the two metal edges of the flask.
• The closed flask is placed under pressure for 30 min before curing.
Processing of the denture is defined as ‘the means by which the denture
base materials are polymerized to form a denture’. (GPT 8th Ed)
• Polymerization of resins can be done in three ways: (i) external heat,
(ii) light-curing and (iii) autopolymerization or self-curing.
• External heat polymerization is most popular.
• Microwave processing can also be done for
polymerizing resins. It requires a microwave oven,
special resin and nonmetal flasks.
• The amount of heat should be controlled when processing acrylic
resin as the reaction is exothermic and the process becomes very
rapid between 140°F and 160°F.
• The temperature of the water should be maintained at or below
• Time required for the temperature of resin to drop to that of water
bath depends on the type and size of flask, quantity of the resin in
mould and temperature of flask when packed.
• Usually, two processing methods are employed for polymerizing
acrylic resin – slow curing and rapid curing.
Slow Processing (Long-Curing Cycle)
• Adequate time is given for the monomer to be incorporated into the
• After packing, the flask is placed in cold water for 30 min.
• Temperature of the control unit is set at 165°F.
• The resin is then cured for 9 h.
• If boiling is also desired in curing, the temperature is held at 160°F
for 9 h and then raised to 212°F for 30 min.
Rapid Processing (Short-Curing Cycle)
• The flasks are placed in the water bath at room temperature.
• Water is slowly heated to 165°F and maintained at this temperature
• The water is then heated to 212°F and temperature is held for 30
• After the acrylic dentures are processed, the flasks are slowly cooled
• Deflasking includes the procedure of removal of the mould from the
flask and separation of the mould from the denture and the cast.
• The flask once cooled is placed in cool water for 15 min before
• Place the flask into the flask ejector and remove the flask from the
artificial stone surrounding the denture.
• Remove the top pour of plaster and stone by placing plaster knife
between the second and third pour.
• The occlusal surface of the denture teeth is now exposed.
• With the dental saw, a cut is made at each corner and the middle of
• Laboratory knife is placed into these cuts and the stone is removed.
• Only the cast denture and stone in the tongue space region remains.
• Again using the laboratory knife, a cut is made in the tongue space
region and the stone is slowly removed.
• During deflasking, it is very important to preserve the cast and the
dentures should not be removed or lifted from the cast.
• Casts and exposed denture surface are cleaned and scrubbed before
Remount procedure is defined as ‘any method used to relate restorations
to an articulator for analysis and/or assist in development of a plan for
occlusal equilibration or reshaping’. (GPT 8th Ed)
• Casts with the processed dentures are replaced over the original
• Attach the mounting to the articulator with sticky wax and close the
• If the incisal pin does not contact the incisal guide table, the vertical
dimension is altered during processing and should be reestablished.
• Articulating paper or carbon paper is used to detect the interceptive
• Selective grinding procedure is initiated for occlusal corrections.
• Refine and equalize the centric occlusion.
• Working and balancing side contacts are perfected.
• Correct the protrusive occlusion.
• The process is continued till the vertical dimension is re-established
and the incisal pin touches the incisal guide table.
• The final refinement of eccentric occlusion is done during clinical
• Cuspal tip is never grinded unless it contacts prematurely in all
excursive movements of the mandible. Always the opposing fossa is
• BULL (buccal, upper and lingual lower) rule is utilized for
perfecting working occlusion. Buccal cusp of upper and lingual cusp of
• To perfect the balanced occlusion, never grind the interfering cusp
tips but grind the cusp inclines.
• For correcting the protrusive interferences in the anterior teeth, labial
surface of the incisal edges of the lower teeth and the lingual surface
of the upper teeth are grinded.
• To correct interferences in the posterior teeth, upper buccal cusp slopes
and the lower lingual cusp slopes are reduced.
Finishing and polishing of complete
Finishing of complete dentures refers to perfecting the final form of the
dentures by removing any excess acrylic resin at the denture border, any
excess resin or stone remaining around the teeth.
Polishing of the complete dentures involves making the dentures
smooth and glossy without changing their contours.
• Any gross excess resin is removed with large acrylic bur on the
• With tapered acrylic bur, small amount of excess resin is removed.
• Remove the stone and sharp ledges around the teeth with sharp BP
• Stone burs, if required, may be used for finishing the denture.
• The dentures can then be smoothened with sand papers of different
• Smoothen the labial, buccal, lingual and palatal external surfaces of
the dentures with wet pumice on a rag wheel at slow speed.
• Keep plenty of pumice on the surface of denture and keep moving
the denture over the polishing buff at all times.
• Polish the resin around the teeth with pumice and brush wheel with
• If stippling was not done during wax-up procedure, but is desired,
it can be accomplished with thin round bur between the second
• Apply polishing compound and polish the dentures to a high lustre
• Store the polished dentures in water until they are inserted in the
• Shim stock is a thin strip of 8–12 microns used to identify the
presence or absence of occlusal or proximal contact.
• Errors in mounting casts on the articulator are detected when the
centric relation is used as a horizontal reference position.
• Mandibular equilibration is the condition in which all the forces
acting on the mandible are neutralized.
• Stippling is done on the surface of the artificial gingiva with minute
pits to simulate the natural appearance of the gingiva.
• Laboratory remount procedure is important, as it helps in correction
of the errors during processing, correcting other errors during bite
Insertion and troubleshooting in
Procedure before Patient Appointment, 176
Procedures Followed during Insertion of the
Clinical Remount Procedure, 177
Procedures in Selective Grinding, 178
Intraoral Methods to Correct Occlusal Disharmony, 181
Postinsertion Instructions to Denture
Troubleshooting in Complete Denture
Prosthesis and its Management, 183
Insertion of complete dentures is the final step in the construction of
dentures. The primary goal is to deliver prosthesis which will enhance
comfort, function and aesthetics. Proper fitting dentures are ensured
Denture placement or insertion is defined as ‘the process of directing a
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