CONTENTS

 INTRODUCTION
 DEFINITION
 DIFFERENCE BETWEEN NATURAL AND ARTIFICIAL OCCLUSION
 CONCEPTS OF COMPLETE DENTURE OCCLUSION
 SEAR’S AXIOMS
 IDEAL REQUIREMENTS
 OCCLUSAL SCHEMES REQUISITES FOR
- Incisive unit
- Working unit
- Balancing unit
 TYPES OF COMPLETE DENTURE OCCLUSION
 BALANCED OCCLUSION
- Requirements
- Controversies
- General considerations/ principles
- Advantage
- Disadvantage
- Types
 LAW’S OF PROTRUSIVE BALANCE
 LAWS OF LATERAL BALANCE
 VARIOUS CONCEPTS PROPOSED TO ATTAIN BALANCED OCCLUSION
 FACTORS INFLUENCING BALANCED OCCLUSION
 IMPACT OF SELECTED VARIABLES ON OCCLUSION FOR RESTORATION
 MONOPLANE/ NON-BALANCED OCCLUSION
 ARRANGEMENT OF TEETH IN BALANCED OCCLUSION
 SUMMARY
 REFERENCES
Seminar - I Balanced Occlusion

BALANCED OCCLUSION

INTRODUCTION

Balance in complete denture is unique and man made. It does not occur in natural teeth and indeed is not needed,

as each tooth is supported independently. Bilateral occlusal balance in natural teeth is considered as a premature contact

on the non-working side (balancing side) and hence is considered pathologic.

The concept of centralizing the working occlusal surfaces requires bringing the occlusal surfaces towards the

center of the denture foundation to their ideal positions, for favorable leverages.

In anteroposterior direction the center of basal seat is in the area of premolar and first molar. This is the area

where food is masticated.

In centric occlusion only the working occlusal units are in contact. The canine and incisors have at lest 1mm

clearance when the teeth are in centric occlusion. The upper and lower incisal units meet only when the mandible is

protruded, and the protrusive balancing unit functions only when the upper and lower incisal units contacts.

DEFINITIONS
Watt & McCrager; Occlusion is defined as static closed relationship of cusps/ masticating surfaces of upper and
lower teeth”.
Or
“The act of closure or state of being closed”.
According to Dorlands Dictionary – “Occlusion is the relation of the maxillary and mandibular teeth when in

functional contact during activity of the mandible”.

Articulation:

Is the dynamic sliding contact of cusps of upper and lower teeth that takes place during closed grinding

movements of the mandible.

Articulation is the continuous change from one occlusal position to next.

BALANCED OCCLUSION:

Has been defined in more than one manner.

“Balanced occlusion is the simultaneous contacting of the maxillary and mandibular teeth on the right and left

and in the posterior and anterior occlusal areas when jaws are in either centric or eccentric relation”. (Heartwell)

“A balanced occlusion is one in which simultaneous and equal contacts are maintained among opposing tooth

surfaces throughout the entire arch and through the entire excursion” (Mohi)

“Balanced occlusion in complete denture can be defined as stable simultaneous contact of the opposing upper

and lower tooth in centric relation position and a continuous smooth bilateral gliding from this position to any eccentric

position within normal range of mandibular function”. (Winkler)

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“It is defined as an occlusion of teeth which presents a harmonious relation of the occluding surfaces in all the

centric and eccentric positions within the functional range of mastication and swallowing”.

“Bilateral simultaneous, anterior, and posterior occlusal contact of teeth in centric and eccentric positions”.

(According to Glossary of Prosthodontics)

Balanced Articulation:

Is a continuing sliding contact of upper and lower cusps all around the dental arches during all closed grinding

movements of the mandible.

Free occlusion:

The inference here is that there are no cuspal interferences in lateral and protrusive movements, but balancing

tooth contact are not necessarily present on the side opposite to the occluding side of the denture.

The difference between free occlusion and balanced occlusion can be easily distinguished by asking the patient

to grind his teeth firmly and then open the mouth, the denture with free occlusion will loosen but the denture with

balanced occlusion will become firmer than ever.

Benett Angle:

The angle formed between the sagittal plane and the average path of advancing condyle as viewed in horizontal

plane during mandibular movement.

Border movement:

Mandibular movements at the limits dictated by anatomic structures as viewed in given plane.

Compensating curve:

The anteroposterior curvature (in the median plane) and the mediolateral curvature (in the frontal plane) in the

alignment of the occluding surfaces and incisal edges of artificial teeth that are used to develop balanced occlusion.

Anteroposterior curve: (GPT)

The anatomic curve 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 molar teeth,

continuing through the anterior border of the mandibular ramus, ending with the anterior most portion of the mandibular

condyle.

Curve of monsoon:

Eponym for a proposed ideal curve of occlusion in which each cusp and incisal edges touches or conforms to a

segment of the sphere 8 inches in diameter with its center in glabella.

Curve of pleasure-/Antimonsoon curve/ frequency curve / probability curve/ reverse curve:

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In excessive wear of the teeth, the abliteration of the cusps and formation of either flat/ cupped out occlusal

surfaces, associated with the reverse of the occlusal plane of premolar, first and second molar teeth, whereby occlusal

surfaces of the mandibular teeth slope facially instead of lingually and those of maxillary teeth incline lingually.

Fischer’s angle:

Angle formed by the intersection of the protrusive and non-working side condylar paths as viewed in the sagittal

plane.

Face bow:

A caliper like instrument used to record the spatial relationship of the maxillary arch to some anatomic reference

point/ points and then transfer this relationship to an articulator.

It orients the dental cast in the same relationship to the opening axis of the articulator.

OCCLUSION

Occlusion is defined as, “Any contact between the incising or masticating surfaces of the maxillary and

mandibular teeth” – GPT.

Another term, which deals with the relationship of the maxillary and mandibular teeth is Dental articulation.

Dental articulation is defined as, “The static and dynamic contact relationship between the occlusal surfaces of

the teeth during function” – GPT

It is generally considered that occlusion deals with the static relationship of opposing teeth and articulation deals

with the dynamic (during movement) relationship of the opposing teeth. In this chapter, we have grouped for convenience

occlusion and articulation as a single phenomenon.

Occlusion is an important factor, which governs the retention and stability of the complete denture in vivo. It is
important for one to know the principles of occlusion before arranging artificial teeth.

DIFFERENCES BETWEEN NATURAL AND ARTIFICIAL OCCLUSION

Occlusion of natural and artificial teeth vary to a great extent. It is important for one to know about these

differences in order to understand the need of balanced occlusion in a

complete denture which is discussed later.

Natural teeth Artificial teeth

 Natural teeth function independently and  Artificial teeth function as a group and the
each individual tooth disperses the occlusal load. occlusal loads are not individually managed.

 Malocclusion can be non-problematic for a  Malocclusions problems

long time

 Non-vertical forces are well tolerated  Non-vertical forces damage the supporting
tissues

 Incising does not affect the posterior teeth.  Incising will lift the posterior part of the

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denture.

 The second molar is the favoured area for  Heavy mastication over the second molar
heavy mastication for better leverage and power. can tilt or shift the denture base.

 Bilateral balance is not necessary and is  Bilateral balance is mandatory to produce

usually considered a hindrance stability of the denture.

 Proprioceptive impulses give feedback to  There is no feedback and the denture rests
avoid occlusal prematurities. This helps the patient in centric relation. Any prematurities in this position
to have a habitual occlusion away from centric can shift the base.
relation.

GENERAL CONCEPTS OF COMPLETE DENTURE OCCLUSION

Unlike natural teeth, the artificial teeth act as a single unit. Hence, there should be a minimum of three contact

points (usually one anterior and two posterior) between the upper and lower teeth at any position of the mandible for even

force distribution and stabilization of the denture.

Complete denture occlusion varies with the type of teeth selected. In posterior teeth selection we discussed

anatomic and non-anatomic teeth. Anatomic teeth should be arranged using balanced occlusion and non-anatomic teeth

are usually arranged using monoplane occlusion.

All occlusal forms should at least have a tripod contact in centric relation. Balanced occlusion should have tripod

contact even in eccentric relation. Before we go in detail about each type of occlusion, let us look at the different concepts

of occlusion.

1. Balanced occlusion

2. Lingualised occlusion (Gysi, Payne, Pound and Murrel)

3. Spherical concept of occlusion (monsoon)

4. Organic concept of occlusion

5. Neutrocentric concept of occlusion (De-Van)

6. Monoplane occlusion

7. Linear occlusion

8. Leneal occlusion

9. Physiologically generated occlusion

Spherical Concept of Occlusion: (Monson)

According to this concept, the anteroposterior and mesiodistal inclines of the artificial teeth should be arranged

in harmony with a spherical surface. (Refer spherical theory in articulators).

Organic Concept of Occlusion:

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Here, the shapes of the teeth are altered to have cusps suitable for the patient. The movement of the condyle

determines the direction of the ridges and grooves of the teeth and the mandibular movements determine other factors like

cusp height, fossa, depth of the fissure, and concavity of the lingual surfaces.

In organic or organized occlusion, the aim is to relate the occlusal surfaces of teeth so that the teeth are in

harmony with the muscles and joints during function. The muscles and joints determine the mandibular position of

occlusion without any tooth guidance. In function, the teeth are supposed to have a passive role and do not influence or

determine the path of mandibular movement. (In normal occlusion, tooth factors determine mandibular movements e.g.

incisal guidance).

Neutrocentric Concept of Occlusion:

According to this concept, the plane of occlusion should be flat and parallel to the residual alveolar ridge. This

concept is similar to the monoplane occlusion used to set non-anatomic teeth. The term neutrocentric denotes an

occlusion that eliminates the anteroposterior and buccolingual inclines in order to direct the forces to the posterior teeth.

SEARS AXIOMS OF COMPLETE DENTURE OCCLUSION

Sears published the following factors to be considered that helps to plan a complete denture occlusion.

 Smaller the area of the occlusal surface, the lesser is the amount of occlusal load transmitted to the supporting

structures.

 Vertical force on a tilted occlusion surface will produce a non-vertical force on the denture.

 Vertical forces acting on a tilted tissue support will produce a non-vertical force on the denture base.

 Vertical force on the denture base lying over the resilient tissues will produce lever forces on the denture.

 Vertical forces acting outside the ridge crest will produce tipping of the denture.

IDEAL REQUIREMENTS OF COMPLETE DENTURE OCCLUSION:

Complete denture occlusion should fulfill the following characteristics:

 Stability of the denture and its occlusion when the mandible is in both centric and eccentric relations.

 Balanced occlusal contacts (tripod contact) during all eccentric movements.

 Unlocking (removing interferences) the cusps mesiodistally so that the denture can settle when there is ridge

resorption.

 The cuspal height should be reduced to control the horizontal forces.

 Functional lever balance should be obtained by vertical tooth to ridge crest relationship. (Lever balance is

balance against leverage forces acting on the denture. Presence of positive contact on the opposing side provides lever

balance. It differs from bilateral balance in that it does not necessarily require three-point contact).

 Cutting, penetrating and shearing efficiency of the occlusal surface is equivalent to that of natural dentition.

 Incisal clearance during posterior functions like chewing.

 Minimal area of contact to reduce pressure while crushing food (Lingualized occlusion).

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 Sharp ridges, cusps and sluiceways to increase masticating efficiency.

OCCLUSAL SCHEME REQUISITES TO FULFILL THE REQUIREMENTS:

Each occlusal scheme has three characteristics, namely, the incisal, working and balancing units. The incisal unit

includes all the four incisors. The working unit includes the canine and the posterior teeth of the side towards which the

mandible moves. The balancing unit includes the canine and the posteriors opposite to the working side.

The ideal requirement of a complete denture occlusion can be fulfilled by creating or providing the following

characteristics for each unit.

Incisal Units:

 Sharp units for improved incising efficiency.

 The units should not contact during mastication. The units should contact only during protrusion.

 Shallow incisal guidance.

 Increased horizontal overlap to avoid interference during settling (the mandibular denture may slide anteriorly as

it settles).

Working Units:

 Cusps for good cutting and grinding efficiency

 Smaller buccolingual width to decrease the occlusal load transferred to the tissues.

 Group function at the end of the chewing cycle in eccentric positions. (During lateral movement if there is

simultaneous contact of the posterior teeth of the working side, it is called group function. In the same situation if the

canine alone contacts then its called canine guided occlusion. Canine guided occlusion and group function are usually

described in relation to the natural teeth).

 The occlusal load should be directed to the anteroposterior centre of the denture.

 The plane of occlusion should be parallel to the mean foundation plane of the ridge.

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Balancing Units:

 The second molars should be in contact during protrusive action (Protrusive balance).

 They should have contact along with the working side at the end of the chewing cycle.

 Smooth gliding contacts should be available for uninterfered lateral and protrusive movements.

TYPES OF COMPLETE DENTURE OCCLUSION:

Complete denture occlusion can be of three types:-

 Balanced occlusion

 Monoplane occlusion

 Lingualized occlusion

Each type has its own indications and contraindications, advantages and disadvantages. The most important type of

occlusion employed in complete dentures is the balanced occlusion.

BALANCED OCCLUSION

It is defined as, “The simultaneous contacting of the maxillary and mandibular teeth on the right and left and in

the posterior and anterior occlusal areas in centric and eccentric positions, developed to lessen or limit tipping or rotating

of the denture bases in relation to the supporting structures” – GPT.

Balanced occlusion can be described as the position of the teeth such that they have simultaneous contact in

centric relation and provide a smooth sliding motion to any eccentric position. A three-point contact (usually one anterior

and two posterior) at centric relation is not sufficient for balanced occlusion instead there should be simultaneous contact

of all the teeth. Remember, balanced occlusion is absent in natural dentition.

Characteristic Requirements of Balanced Occlusion:

A balanced occlusion should have the following characteristics:-

 All the teeth of the working side (central incisor to second molar) should glide evenly against the opposing teeth.

 No single tooth should produce any interference or disocclusion of the other teeth.

 There should be contacts in the balancing side, but they should not interfere with the smooth gliding movements

of the working side.

 There should be simultaneous contact during protrusion.

Importance of Balanced Occlusion:

Balanced occlusion is one of the most important factors that affect denture stability. Absence of occlusal balance

will result in leverage of the denture during mandibular movement.

Sheppard stated that, “Enter bolus, Exit balance”. According to this statement, the balancing contact is absent

when food enters the oral cavity. This makes us think that balanced occlusion has not function during mastication; hence,

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it is not essential in a complete denture. But this is not true. Brewer reported the importance of balanced occlusion. He

stated that on an average, a normal individual makes masticatory tooth contact only for 10 minutes in one full day

compared to 4 hours of total tooth contact during other functions. So, for these 4 hours of tooth contact, balanced

occlusion is important to maintain the stability of the denture. Hence, balanced occlusion is more critical during

parafunctional movements.

General Considerations or Principles for Balanced Occlusion:

The following points should be considered while developing balanced occlusion:

 Ideal-balanced occlusion can be achieved in cases with wide and large ridges and in complete dentures, with

teeth arranged close to the ridge.

 Complete dentures that have teeth arranged away from the ridge and those that rest on narrow and short ridges

will have poor balanced occlusion.

 Teeth that have a narrow buccolingual width and those that rest on wide ridges provide ideal-balanced occlusion.

 Ideal balance can be achieved by arranging the teeth slightly on the lingual side of the crest of the ridge.

Arranging the teeth buccally will lead to poor balanced occlusion. If the teeth are set outside the ridge the denture may

elevate on one side during tooth contact. Stability of the denture against these lever forces is called as lever balance.

Lever balance is different from balanced occlusion. It can be safely quoted that lever balance is also necessary for

balanced occlusion (Refer ideal requirements of balanced occlusion).

 The complete denture should be designed in such a way that the forces of occlusion are centered

anteroposteriorly in the denture.

Types of balanced Occlusion:

Occlusion balance or balanced occlusion can be classified as follows:-

 Unilateral balanced occlusion

 Bilateral balanced occlusion

 Protrusive balanced occlusion

 Lateral balanced occlusion

Unilateral balanced occlusion: This is a type of occlusion seen on occlusal surfaces of teeth on one side when they

occlude simultaneously with a smooth, uninterrupted glide. This is not followed during complete denture construction. It

is more pertained to fixed partial dentures.

Bilateral balanced occlusion: This is a type of occlusion that is seen when simultaneous contact occurs on both sides in

centric and eccentric positions. Bilateral balanced occlusion helps to distribute the occlusal load evenly across the arch

and therefore helps to improve stability of the denture during centric, eccentric or parafunctional movements.

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For minimal occlusal balance, there should be at least three points of contact on the occlusal plane. More the

number of contacts, better the balance. Bilateral balanced occlusion can be protrusive or lateral balance.

Advantages of bilateral balanced occlusion:

The statement “enter bolus exit balance” has cast suspicion on the value of smooth, gliding, non-interfering

bilateral tooth contacts.

It implies that when a food bolus is kept on one side there will not be occlusion on other side and the denture

will tend to drop on that side. This will occur whether the occlusion is balanced/not. It has therefore been argued that

conventional “balanced occlusion” is not necessary in eccentric position.

The advantage of balanced occlusion however occurs when the teeth do finally penetrate the food in eccentric

position then the all-around contact reseals the dentures.

The bilateral balanced occlusion is more important during activities such as swallowing saliva, closing to reseat

the denture, and the bruxing of the teeth during times of stress.

A combination of tissue resiliency and denture movement during function accounts for the high frequency of the

non-chewing/ balancing side contacts.

Sheppard (1964) suggested the expression “Enter bolus, enter balance”.

Balancing the occlusion in complete denture is like changing stumbling prose to poetry.

Advantages:

 Better masticatory efficiency

 Better stability of denture base

 Reduced trauma, improved comfort

 The functional movements are possible

Disadvantages:

 Time consuming

 Cannot be used in all patients

Protrusive balanced occlusion:

This type of balanced occlusion is present when mandible moves in a forward direction and the occlusal contacts

are smooth and simultaneous anteriorly and posteriorly. There should be at least three points of contact in the occlusal

plane. Two of these should be located posteriorly and one should be located in the anterior region. This is absent in

natural dentition.

The factors that govern protrusive balance:

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 The inclination of the condylar path: This inclination recorded on the patient represents the path traveled by the

condyle in protrusion which is modified by the combined action of all the tissues in the temoromandibular joint and the

ridges covered by the recording bases.

 Angle of the incisal guidance chosen for the patient.

 Angle of the plane of occlusion.

 The compensating curves chosen for orientation with the condylar path and the incisal guidance.

 Cuspal height and inclination of the posterior teeth.

Lateral balanced occlusion:

In lateral balance, there will be a minimal simultaneous three point contact (one anterior, two posterior) present

during lateral movement of the mandible.

Lateral balanced occlusion is absent in normal dentition. When a dentulous person with canine guided occlusion

moves his mandible to the right, there will be canine guided disocclusion of all his teeth. That is, the canine will be the

only tooth that contacts the opposing tooth. Even the canine of the opposite side will not have contact.

If this relationship is followed during teeth arrangement, then the denture will lose its stability due to lever

action. To prevent this the teeth should be arranged such that there is simultaneous tooth contact in the balancing and

working sides.

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LAWS OF LATERAL BALANCE:

 Angle of inclination of the condylar path on the balancing side.

 Angle of inclination of the incisal guidance and cuspid lift.

 Angle of inclination of the plane of occlusion on the balancing side and working side.

 Compensating curve on the balancing side and working side.

 The buccal cusp heights or inclination of the teeth on the balancing side.

 The lingual cusp heights or inclination on the working side.

 The Bennett side shift on the working side.

Steep cusps produce more displacement of the denture base than shallower or cuspless forms. The forces of occlusion

acting on a complete dentures should be balanced from right to left and anterior to posterior direction.

An increase in any of the above factors will affect balanced occlusion leading to compromised stability in the

denture.

If the vertical overlap of the anterior teeth is increased for aesthetic and phonetic reasons, then the horizontal

overlap should be adjusted to reduce the incisal guidance angle.

This adjustment provides space for free movement of the anterior teeth. Without this adjustment, there will be

increased anterior interference leading to initial instability of the denture base during protrusion. In the long run, this may

lead to resorption of the residual alveolar ridge in the anterior region.

Concepts Proposed to Attain Balanced Occlusion:

Many authors proposed different concepts for obtaining balanced occlusion. Most of them are not in use now

and carry only a historical significance. Any way, we must know these concepts to understand how the present concepts

have been derived from them.

Gysi’s Concept: He proposed the first concept towards balanced occlusion in 1914. He suggested that arranging 33 0

anatomic teeth could be used under various movements of the articulator to enhance the stability of the denture.

French’s concept (1954): He proposed lowering the lower occlusal plane to increase the stability of the dentures along

with balanced occlusion. He arranged upper first premolars with 5 0 inclination, upper second premolars with 10 0

inclination and upper molars with 150 inclination. He used modified French teeth to obtain balanced occlusion.

Sears’s concept: He proposed balanced occlusion for non-anatomical teeth using posterior balancing ramps or an

occlusal plane which curves anteroposteriorly and laterally.

Pleasure’s concept: Pleasure introduced a pleasure curve or the posterior reverse lateral curve to align and arrange the

posterior teeth in order to increase the stability of the denture.

Frush’s Concept: He advised arranging teeth in a one-dimensional contact relationship, which should be reshaped during

try-in to obtain balanced occlusion.

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Hanau’s Quint: Rudolph L. Hanau proposed nine factors that govern the articulation of artificial teeth. They are:

 Horizontal condylar inclination

 Compensating curve

 Protrusive incisal guidance

 Plane of orientation

 Buccolingual inclination of tooth axis

 Sagittal condylar pathway

 Sagittal incisal guidance

 Tooth alignment

 Relative cusp height

These nine factors are called the laws of balanced articulation. Hanau later condensed these nine factors and formulated

five factors, which are commonly known as Hanau’s quint:

 Condylar guidance

 Incisal guidance

 Compensating curves

 Relative cusp height

 Plane of orientation of the occlusal plane

These factors are described in detail later.

Trapozzano’s Concept of Occlusion:

He reviewed and simplified Hanau’s quint and proposed his Triad of Occlusion. According to him, only three

factors are necessary to produce balanced occlusion. He dismissed the need for determining the plane of occlusion to

produce balanced occlusion. He said that the plane of occlusion could be shifted to favour weak ridges, hence, its location

is not constant and is variable within the interarch distance.

He also dismissed the need for setting compensating curves, because, he suggested that when we arrange cusped

teeth in principle these curves are produced automatically. He considered that compensating curve as a passive factor,

which is a resultant of setting cusped teeth.

Though his triad was simpler than the Hanau’s quint, it eliminated the important compensating curves and plane

of orientation.

Boucher’s concept: Boucher confronted Trapozzano’s concept and proposed the following three factors for balanced

occlusion.

 Orientation of the occlusal plane, the incisal guidance and the condylar guidance.

 The angulation of the cusp is more important than the height of the cusp.

 The compensating curve enables one to increase the height of the cusp without changing the form of the teeth.

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He also stated that, “the plane of occlusion should be oriented exactly as it was when natural teeth were present”.

According to him, the plane of occlusion cannot be changed to favour weak ridges and that the teeth should be located in

their original position. He believed it was necessary to fulfill the anatomical and physiological needs.

Boucher also emphasized the need for the compensating curve. He stated that, “the value of the compensating

curve is that it permits alteration of cusp height without changing the form of the manufactured teeth… If the teeth

themselves do not have any cusps, the equivalence of a cusp can be produced by a compensating curve”.

Lott’s concept: Lott clarified Hanau’s laws of occlusion by relating them to the posterior separation that is a resultant of

the guiding factors.

 The greater the angle of the condylar path, the greater is the posterior separation during protrusion.

 The greater the angle of the overbite, the greater is the separation in the anterior and posterior regions

irrespective of the angle of the condylar path.

 The greater the separation of the posterior teeth the greater or higher must be the compensating curve.

 Posterior separation beyond the balancing ability of the compensating curve can be balanced by the introduction

of the plane of orientation.

 The greater the separation of the teeth, the greater must be the height of the cusps of the posterior teeth.

Levin’s concept: Bernard Levin believed that it was not necessary to consider the plane of occlusion because it was not

very useful practically. Levin also states that the plane of occlusion can be slightly altered by 1-2 mm in order to improve

the stability of a denture.

He named the other four factors of occlusion as the Quad. The essentials of a quad are:-

 The condylar guidance is fixed and is recorded from the patient. The balancing condylar guidance will include

the Bennett movement of the working condyle. This may or may not affect the lateral balance.

 The incisal guidance is usually obtained from patient’s aesthetic and phonetic requirements. However, it can be

modified for special requirements. E.g., the incisal guidance is decreased for flat ridges.

 The compensating curve is the most important factor in obtaining occlusal balance. Monoplane or low cusp teeth

must employ the use of compensating curve.

 Cusp teeth have the inclines necessary for balanced occlusion but nearly always are used with a compensating

curve.

FACTORS INFLUENCING BALANCED OCCLUSION:

Though many authors questioned the necessity of all the five factors in a Hanau’s quint, it is still considered as

the basic determinant of balanced occlusion. The five basic factors that determine the balance of an occlusion are:-

i. Inclination of the condylar path or condylar guidance

ii. Incisal guidance

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iii. Orientation of the plane of occlusion or occlusal plane

iv. Cuspal angulation

v. Compensating curves.

There should be a balance within these five factors. The incisal and condylar guidances produce a similar effect on

balanced occlusion (they increase posterior tooth separation). Similarly, the other three factors have a common effect on

balanced occlusion (they decrease the posterior tooth separation). The effect of the incisal and condylar guidances should

be counteracted by the other three factors to obtain balanced occlusion. If this counteractive mechanism is lost, the

balance of occlusion is lost.

Let us discuss in general how these factors affect the balance during protrusion. The incisal guide angle denotes

the angle formed by the palatal surface of the upper anterior against the horizontal plane. The incisal guidance can be

raised by altering the labial proclination, overjet and overbite of the maxillary anterior, so that the incisal guide angle

becomes steeper.

When the patient with a steep incisal guidance brings his mandible forward, there will be more jaw separation.

This is because the movement of the mandible is controlled by the lingual surface of the upper anteriors (The upper

incisors are more vertically placed in cases with a steep incisal guidance). Increase in jaw separation will lead to

disocclusion of the posterior teeth leading to loss of tripod contact which in turn lead to lifting of the posterior part of the

denture during incising functions. If the posterior part of the denture lifts during incisal function, it simply means that the

balanced occlusion is absent. The condylar guidance has a similar effect on the denture.

To prevent the lifting of the posterior part of the denture, the compensating curve, cuspal angulation of the teeth,

and the plane of occlusion should be modified such that a tripod contact is preserved during protrusion.

If the compensating curve is made steeper (raised), the posterior contact will be preserved during protrusion. If

the cuspal height or angulation is increased, again the posterior contact will be maintained during protrusion. Similarly, if

the plane of occlusion is oriented / tilted so that it is higher posteriorly, then the posterior contact will be maintained

during protrusion.

Thus, we understand that when the incisal guidance or condylar guidance is high, the other three factors should

also be raised to compensate the effects of the incisal and condylar guidance and vice-versa.

Now we shall discuss in greater detail about the significance of each factor in balanced occlusion.

Inclination of the condylar path is also called as the first factor of occlusion. This is the only factor, which can be

recorded from the patient. It is registered using protrusive registration (i.e. the patient is asked to protrude with the

occlusal rims. Inter-occlusal record material is injected between the occlusal rims in this position. The occlusal rims

with the inter occlusal record are transferred to the articulation. Since the occlusal rims are in a protrusive relation, the

upper member of the articulator is moved back to accommodate them. The inter-occlusal record is carefully removed and

the upper member is allowed to slide forward to its original position. The condylar guidance should be adjusted (rotated)

till the upper member slides freely into position. It is transferred to the articulator as the condylar guidance.

DEPT. OF PROSTHODONTICS 14
Seminar - I Balanced Occlusion

Increased in the condylar guidance will increase the jaw separation during protrusion. This factor of balance

occlusion cannot be modified. All the other four factors of occlusion should be modified to compensate the effects of this

factor. In patients with a steep condylar guidance, the incisal guidance should be decreased to reduce the amount of jaw

separation produced during protrusion and vice versa. But it should be remembered that the incisal guidance cannot be

made very steep because it has its own ill effects.

Incisal guidance:

This is defined as, “The influence of the contacting surface of the mandibular and maxillary anterior teeth on mandibular

movements”.

It is called as the second factor of occlusion. It is determined by the dentist and customized for the patient

during anterior try-in. It acts as controlling path for the movements of the casts in an articulator. It should be set

depending upon the desired overjet and overbite planned for the patient. If the overjet is increased, the inclination of the

incisal guidance is decreased. If the overbite is increased, then the incisal inclination increases. The incisal guidance has

more influence on the posterior teeth than the condylar guidance. This is because the action of the incisal inclination is

closer to the teeth than the action of the condylar guidance.

During protrusive movements, the incisal edge of the mandibular anterior teeth move in a downward and

forward path corresponding to the palatal surface of the upper incisors. This is known as the protrusive incisal path or

incisal guidance. The angle formed by this protrusive path to the horizontal plane is called as the protrusive incisal path

inclination or the incisal guide angle.

This influences the shape of the posterior teeth. If the incisal guidance is steep compensatory curve is needed to

produce balanced occlusion (explained previously). In a complete denture, the incisal guide angle should be as flat (more

acute) as possible. Hence, while arranging the anterior teeth, for aesthetics, a suitable vertical overlap and a horizontal

overlap should be chosen to achieve balanced occlusion. Also, the incisal guidance cannot be altered beyond limits. The

location and angulation of the incisors are governed by various factors like aesthetics, function and phonetics, etc. The

procedure for setting up the incisal guidance was described under articulation.

Plane of occlusion or occlusal plane:

It is defined as, “An imaginary surface which is related anatomically to the cranium and which theoretically touches the

incisal edges of the incisors and the tips of the occluding surface of the posterior teeth. It is not a plane in the true sense

of the word but represents the mean curvature of the surface.

It is established anteriorly by the height of the lower canine, which nearly coincides with the commissure of the

mouth and posteriorly by the height of the retromolar pad. It is usually parallel to the ala-tragus line or Camper’s line. It

can be slightly altered and its role is not as important as other factors. Tilting the plane of occlusion beyond 10 0 is not

advisable.

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Seminar - I Balanced Occlusion

Orientation of the Occlusal Plane

The term “Plane of orientation” (by Hanau) refers to the vertical location of the anteroposterior alignment of the

occlusal plane in the space between the upper and lower ridges.

The plane of occlusion is established in the anterior by the height of the lever cuspid which is nearly coincident

with the commissure of the mouth and in the posterior by the height of the retromolar pad. It is also related to the ala-

tragus line/camper’s plane.

1) Orientation of occlusal plane to the ala-tragus or Camper’s line:

Boucher defines it as “The line running from the inferior border of the ala of the nose to the superior border of

the tragus of the ear”.

2) Cephalometrically planned adjustable plane:

Cephalometrically, a relationship has been shown to exist between the angle of occlusal plane relative to the

Frankfurt plane on one hand and the angle formed between cephalometric points, porion, nasion and the anterior nasal

spine (The Po NANS angle).

Y’ = 83.4307 – (0.9907 – X)

Where X = PoNANS angle value

Y’ = Occlusal plane angle

Compensating curve:

It is defined as, “The antero-posterior and lateral curvatures in the alignment of the occluding surfaces and

incisal edges of artificial teeth which are used to develop balanced occlusion” – GPT.

It is an important factor for establishing balanced occlusion. It is determined by the inclination of the posterior

teeth and their vertical relationship to the occlusal plane. The posterior teeth should be arranged such that their occlusal

surfaces form a curve. This curve should be in harmony with the movements of the mandible guided posteriorly by the

condylar path.

A steep condylar path requires a steep compensatory curve to produce balanced occlusion. If a shallow

compensating curve is given for the same situation, there will be loss of balancing molar contacts during protrusion

(explained before).

There are two types of compensating curves namely:

 Anteroposterior curves

 Lateral curves

Curve of Spee, Wilson’s curve and Monson’s curve are associated only with natural dentition. In complete dentures

compensating curves similar to these curves should be incorporated to produce balanced occlusion.

Anteroposterior Compensating Curves:

These are compensatory curves running in an anteroposterior direction. They compensate for the curve of Spee

seen in natural dentition.

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Seminar - I Balanced Occlusion

Compensating Curve for Curve of Spee:

Curve of Spee is defined as, “Anatomic curvature of the occlusal alignment of teeth beginning at the tip of the

lower canine and following the buccal cusps of the natural premolars and molars, continuing to the anterior border of the

ramus as described by Graf von Spee” – GPT.

It is an imaginary curve joining the buccal cusps of the mandibular posterior teeth starting from the canine

passing through the head of the condyle. It is seen in the natural dentition and should be reproduced in a complete

denture. The significance of this curve is that, when the patient moves his mandible forward, the posterior teeth set on this

curve will continue to remain in contact. If the teeth are not arranged according to this curve, there will be disocclusion

during protrusion of the mandible (Christensen’s phenomenon).

Prominence of Compensating Curve:

According to Glossary of Prosthodontic terms, compensating curve is defined as, “anteroposterior and lateral

curvature in the alignment of occlusal surfaces and the incisal edges of artificial teeth which is used to develop balanced

occlusion”.

It is determined by the inclination of the posterior teeth and their vertical relationship to the occlusal plane so

that it is in harmony with the movement of mandible as guided posteriorly by the condylar path.

Thielmann’s Formula:-

In order to obtain smooth balanced occlusion, the compensating curve must be in harmony with other factors of

occlusion.

This relationship is expressed in Hanau Quint. It is expressed even more clearly by Thielmann’s formula.

Balanced occlusion = K.I

Op. C. OK

K – inclination of condylar guidance

I – inclination of incisal guidance

C – height of cusps

OP – inclination of plane of orientation

OK – prominence of compensating curve

Cusp plane and Cusp plane angle:

When the two buccal cusp tips and the highest situated lingual cusp tip are connected with straight lines these

lines circumscribe a small plane, which is called “Cusp plane”.

The connecting line between the buccal cusps indicates the sagital slope, and the alignment of these lines forms

the compensating curve.

The inclination of cusp plane to the plane of orientation is called “Cusp plane angle”.

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Seminar - I Balanced Occlusion

Compensating curve formula:-

The action of compensating curve is as follows:-

The cusp angulation () of the protrusive facets of the molars must be reduced with an equal to the cusp plane

angle (w). This relation can be expressed by –

C=-W

C – Cusp angulation

 - Cusp angulation according to cusp incline table

W – Cusp plane angle

This formula is called “formula of the compensating curve”.

Lateral Compensating Curves:

These curves run transversely from one side of the arch to the other. The following curves fall in this category:

Compensating curve for Monson Curve:

Monson’s curve is defined as, “The curve of occlusion in which each cusp and incisal edge touches or conforms

to a segment of the sphere of 8 inches in diameter with its center in the region of the Glabella”. GPT.

This curve runs across the palatal and buccal cusps of the maxillary molars. During lateral movement the

mandibular lingual cusps on the working side should slide along the inner inclines of the maxillary buccal cusp. In the

balancing side the mandibular buccal cusps should contact the inner inclines of the maxillary palatal cusp. This

relationship forms a balance.

Only if the teeth are set following the Monson’s curve there will be lateral balance of occlusion.

Compensating Curve for Anti-Monson or Wilson Curve:-

Wilson’s curve is defined as, “A curve of occlusion which is convex upwards”. – GPT.

This curve runs opposite to the direction of the Monson’s curve. This curve is followed when the first premolars

are arranged. The premolars are arranged according to this curve so that they do not produce any interference to lateral

movements.

Reverse Curve:-

“A curve of occlusion which in transverse cross-section conforms to a line which is convex upward”. –GPT. It

was originally developed to improve the stability of the denture. The reverse curve was modified by Max Pleasure to

form the pleasure curve.

Pleasure Curve:-

“A curve of occlusion which in transverse cross-section conforms to a line which is convex upward except for

the last molars”. – GPT.

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Seminar - I Balanced Occlusion

It was proposed by Max Pleasure. He proposed this curve to balance the occlusion and increase the stability of

the denture. Hence the first molar is horizontal, the second premolar is lingually tilted and second molar is buccally tilted.

It is a modification of reverse curve in that it does not involve the second molars. This curve runs from the palatal cusp of

the first premolar to the distobuccal cusp of the second molar.

Cuspal angulation:

Cusp angle is defined as, “The angle made by the average slope of a cusp with the cusp plane measured mesiodistally or

buccolingually”. – GPT.

The cusps on the teeth or the inclination of the cuspless teeth are important factors that modify the effect of

plane of occlusion and the compensating curves. The mesiodistal cusps lock the occlusion, such that repositioning of

teeth does not occur due to settling of the base.

In order to prevent the locking of occlusion, the mesiodistal cusps are reduced during occlusal reshaping. In the

absence of mesiodistal cusps, the buccolingual cusps are 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 a decreased overbite. Teeth with steep cusps will produce occlusal

interference in these cases.

In cases with a deep bite (steep incisal guidance), the jaw separation is more during protrusion. Teeth with high

cuspal inclines are required in these cases to produce posterior contact during protrusion.

Thus, we discussed the various concepts and factors affecting balanced occlusion. The method of occlusal

reshaping is not discussed in detail due to its complexity. It is necessary for a dentist to at least know that occlusal

reshaping is done after teeth arrangement to produce balanced occlusion.

Inclination of the Cusps:

It refers to the angle between the total occlusal surface of the tooth and the inclination of the cusp in relation to

that surface. For e.g. 33-degree tooth indicates that the mesial slopes of the cusp make 33 0-angle with a plane touching the

tips of all the cusps of teeth. In other words the plane of reference (the horizontal plane) would be at right angles to the

vertical axis of the tooth.

Swenson’s Formula:-

Swenson’s formula is an empirical formula and clarifies the relationship between the sagital cusp inclination of

the incisal guidance.

Cusp inclination = Incisal inclination + Fraction of distance from incisal guidance (Condyle inclination - Incisal

inclination) on the working side.

Cusp inclination = Incisal inclination + Fraction of distance from incisal guidance (Difference between incisal

guidance and condylar path inclination) here incisal inclination becomes zero.

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Seminar - I Balanced Occlusion

Gysi’s formula for the second molar:

Gysis formula for the angulation of second molar is –

Angulation of M2 = Condyle guide inclination + Incisal guide inclination

2

That is EM2 = B + V
2

B – Condyle guide inclination

V – Incisal guide inclination

Gysi’s formula assumed to be an empirical formula, giving the dentist a conception of the approximate cusp

angulation and setting of the incisal table of an adjustable articulator.

Impact of Selected Variables on Occlusal Form of Restoration:

Posterior Determinants Variation Impact on Restoration
* Inclination of articular - Steeper - Posterior cusps may be taller
eminence
- Flatter - Posterior cusp may be shorter
* Medial wall of glenoid fossa - Allows more lateral translation - Posterior cusp must be shorter
- Allows minimal lateral - Posterior cusp may be taller
translation
* Intercondylar distance - Greater - Smaller angle between the
laterotrusive and mediotrusive
movement
- Lesser - Increased angle
Anterior Determinants
* Horizontal overlap of anterior - Increased - Posterior cusps must be shorter
teeth
- Reduced - Posterior cusps may be taller
* Vertical overlap of anterior - Increased - Posterior cusps may be taller
teeth
- Reduced - Posterior cusps must be shorter
Other
- Occlusal plane - More parallel to condylar - Posterior cusp must be shorter
guidance
- Less parallel to condylar - Posterior cusp may be taller
guidance
* Curve of spee - More convex (short radius) - The post-cusp mustbe shorter
- Less convex (larger radius) - Post-cusp ma be longer
ARRANGEMENT

Arrangement of anatomic type artificial teeth into balanced occlusion:

1. Amount of overjet should not be less than 2mm in centric relation. Anterior teeth set according to best possible

esthetics, phonetics and function.

DEPT. OF PROSTHODONTICS 20
Seminar - I Balanced Occlusion

2. Steep condylar guidance or steep incisal guidance and combination of them suggest prominent compensating

curve with steep anteroposterior and lateral cusp height. This is detrimental to the stability of denture. Condylar guidance

must be accepted as recorded but the incisal guidance should be kept as flat as possible.

3. The upper premolars should be positioned so as to present a normal dental arch outline. Practically a straight

line from the canines to the mesiobuccal cusp of upper first molar, thus, contributing to esthetics. In other words, the

buccal vestibule should be in evidence when the patient smiles.

4. The lower first premolars may be positioned buccally to the crest of the ridge occasionally in order to occlude

correctly with the upper premolars.

5. When it is found necessary to grind artificial teeth at the gingival end, care should be used to preserve as much

as the buccal side of the ridge lap as possible, even though the tooth material representing the buccal surface may then be

very thin. Both the upper and lower premolars should present buccal surface of sufficient length to place the gingival

finishing line in harmony with that of the canines, short premolars are detrimental to esthetics and should not be used.

6. Before cusp inclines are altered by grinding, the inclinations of long axes of the opposing teeth should be

rotated about centric occlusal contact in an attempt to establish the desired balancing contact.

7. After artificial teeth have been satisfactorily arranged, the final waxing should be done in a manner which will

provide the desired buccal, labial and lingual contours without destroying the occlusion, already established.

8. Once the bases are sealed to their respective casts, all routine laboratory procedures are carried out.

MONOPLANE OR NON-BALANCED OCCLUSION:

It is an arrangement of teeth with form or purpose. It includes the following concepts of occlusion:

 Spherical theory

 Organic occlusion

 Occlusal balancing ramps for protrusive balance

 Transographics

Concepts of Non-balanced Occlusion:

The concept of monoplane occlusion was a result of Sheppard’s statement “Enter Bolus, Exit Balance”. This

statement questioned the need for balanced occlusion.

Consecutively many clinicians came with different concepts of non-balanced occlusion for complete dentures.

Pound’s Concept:-

He proposed a monoplane occlusion which stresses the importance of phonetic and aesthetics for anterior teeth.

The posterior teeth on the other hand have a sharp upper lingual cusp and a wide lower central fossa. The buccal cusps of

the lower posterior teeth were reduced to avoid non-vertical occlusal forces. Effectively, it was a lingualized occlusion

DEPT. OF PROSTHODONTICS 21
Seminar - I Balanced Occlusion

wherein there is no buccal contact of upper and lower teeth and the occlusal surfaces are reduced such that they lie in a

triangle formed between the mesial end of the canine and the two sides of the retromolar pad.

Cusp form gold occlusal concept:-

As the name suggests, it uses teeth with a 330 cusp form made on a gold surface. According to this concept, the

anteriors are set by aesthetic and phonetic requirements and the posteriors are set with vertical overlap such that there is

disocclusion due to the canine during eccentric movement of the mandible.

Hardy’s concept:-

He proposed a flat occlusal plane set with non-anatomical teeth for complete denture occlusion. Metal insert

teeth were also proposed.

Occlusal pivot by Sear:

The pivots were used to place the mandible in equilibrium by concentrating the load in the molar regions. This

scheme reduced the injury to the temporomandibular joint and also reduced the stress in the anterior region.

Kurth’s concept:-

He proposed a non-balanced occlusion set with flat posterior teeth in a horizontal plane without any balancing

ramps. The teeth were set in a flat plane anteroposteriorly with a reverse lateral curve. This reverse lateral curve is not a

compensating curve.

Philip M. Jones scheme of non-balanced occlusion:

In this scheme, non-anatomical teeth were arranged with the following modifications:

 A different articulator that could fit large casts were used.

 The maxillary and mandibular teeth are arranged without any vertical overlap. The jaw relation determined the

amount of horizontal overlap.

 The maxillary posteriors are set first. The occlusal plane should fulfill the following requirements:

- The occlusal plane should divide the inter-arch space equally.

- The occlusal plane should be parallel to the mean denture base foundation.

- The occlusal plane should lie at the junction of the upper and middle thirds of the retromolar pad.

 During final arrangement, there should be complete intercuspation between the upper and lower posterior teeth

except the second molar.

 The occlusal surface of the upper second molar should be 2 mm above the plane of occlusion (hence it is out of

occlusion) and parallel to the occlusal surface of the lower second molar.

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Seminar - I Balanced Occlusion

These modifications are done so that the premolars and the first molars are the primary masticators and the second molars

are just non-functional space fillers.

General Considerations:

The following points have to be considered while using a non-balanced occlusion for a denture:

 Opposing artificial teeth should not contact when the jaws are in eccentric relation, because it may give

destabilizing forces to the basal seat area. The architecture of the basal seat does not allow tooth contact when the

mandible is in eccentric position.

 Tooth contact should occur only when the mandible is in centric relation to the maxilla.

 The patient should be encouraged to repeat the mandibular movements till there is no discomfort in centric

relation.

Lingualized Occlusion

It was first proposed by Alfred Gysi in 1927. This type of occlusion involves the use of a large upper palatal

cusp against a wide lower central fossa. In this scheme, the buccal cusps of the upper and lower teeth do not contact each

other. Clough reported that 67% of the patients preferred lingualized occlusion due to its superior chewing efficiency.

Many clinicians contributed to the concept of lingual occlusion. Pound proposed non-balanced lingualized

occlusion. Payne proposed the use of 30 0 anatomical teeth which are later reshaped to obtain lingual occlusion. This

scheme had complete intercuspation without any deflective occlusal contacts.

Myerson’s Lingualzied Integration (MLI):

Myerson proposed specialized tooth molds for arranging teeth in lingualized occlusion. He proposed two

different molds for the maxillary posteriors namely control contact (cc) mold and maximum contact (MC) mold. The

remaining teeth are common for both these molds.

He advocates the use of ‘MC’ mold for patients who can reproduce accurate centric position and the ‘CC’ mold

for patients with variations in centric position.

These teeth provide maximal intercuspation, good cuspal height to perform occlusal reshaping, and a natural and

pleasing appearance. The ‘MC’ mold maxillary posteriors have taller cusps with a more anatomical appearance compared

to the ‘CC’ mold. The ‘MC’ mold also offers a more ‘exacting occlusion’.

CONCLUSION

Occlusion should be smooth running, the importance of occlusion and articulation for maintenance of CD

stability has never been underestimated, but overlooked. No matter how great amount of initial retention, the impression

may demonstrate. Because the occlusion we are going to provide gives more stability which indirectly gives the retention.

DEPT. OF PROSTHODONTICS 23
Seminar - I Balanced Occlusion

“Balanced occlusion is making a stumbling phrase into a beautiful poem” so dentist (prosthodontist) should

provide occlusion, which should compatible with the stomatognathic system and should provide a efficient mastication

and esthetics, without any physiologic abnormality.

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REFERENCES:

1) Boucher’s Prosthodontic Treatment for Edentulous Patient”, 12th edition, Zarb-Bolender.

2) Boucher’s Prosthodontic Treatment for Edentulous Patient”, 10th edition, Zarb-Bolender, Hickey, Carlsson.

3) Essentials of Complete Denture Prosthodotics, 2nd Edition, Sheldon-Winkler.

4) Complete Denture Prosthodontics – Swenson.

5) Text Book of Complete Dentures, 5th edition, Rahn, Charles Heartwell.

6) Complete Denture Prosthodontics – Sharry.

7) Journal of Prosthetic Dentistry 1972; 27:246

8) Journal of Prosthetic Dentistry 1978; 39 : 484.

9) Journal of Prosthetic Dentistry 1977; 38:601.

10) Journal of Prosthetic Dentistry 1972; 25:94-100.

11) Journal of Prosthetic Dentistry 2001; 85(1):15-19.

12) Journal of Prosthetic Dentistry 1971; 25(2):121-138.

13) Journal of Prosthetic Dentistry 1971; 26(5):448-455.

14) Journal of Prosthetic Dentistry 1981; 57 : 704-707.

15) British Dental Journal 1997; 128:1140.

16) Journal of Prosthetic Dentistry 2000; 84(4):390-393.

DEPT. OF PROSTHODONTICS 25