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INTRODUCTION

The method of recording the jaw relationships using baseplates and occlusion

rims, is widely carried out in clinical practice. However, as many dentures with an

unstable occlusion are seen, it is thought that minor errors tend to occur easily using

this technique. There are various reasons to explain this. If the clinician is not

accustomed to the procedure of softening the wax, it will be difficult to soften the

rims evenly. Without uniformly softened rims, an exact record cannot be expected.

When the baseplates poorly fit the alveolar ridges, they are displaced by sliding over

the occlusal plane during recording and thus the jaw registration is carried out with

displaced rims. In addition, as the mucosa of the alveolar ridge is compressible, some

portions of the baseplate settle into the mucosa slightly and another portion is raised

up, but this depends on the case. In a case with severe ridge resorption, the baseplate

will be easily displaced. In a patient with a loose temporomandibular joint or wearing

an existing denture with a malocclusion for a long time, the eccentric relation might

be easily recorded by a little undue pressure.

In any case, it requires great skill for the horizontal and vertical jaw relations

to be recorded simultaneously just by using the baseplates to establish an exact jaw

relationship. The chairtime will also be prolonged, and thus the physical fatigue of the

patient will increase. To solve these problems, the author divides the procedure into

two stages. The gothic arch tracer is used for recording the horizontal jaw relation.

The patient must come to the clinic once more, but as the final decision can be left to

the use of the gothic arch tracer, the procedure for recording the vertical relation using

baseplates can be performed stress-free and moreover the total chairtime for the

recording jaw relations is shortened.

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HORIZONTAL PLANE BORDER MOVEMENTS

A mandibular element to be understood before recording maxillomandibular

relationships and making tooth arrangements for complete dentures is border

positions. Border refers to the boundary of a surface and may imply the limiting line.

Border position is defined as the most posterior position of the mandible at any

specific vertical relation.

The border positions are limited by nerves, bones muscle, teeth when present

and ligaments. The limiting is not a simple mechanical stoppage but a physiologic

control through the neuromuscular system. The envelopes of motion of the mandible

in the border positions has been recorded in three planes horizontal, frontal and

sagittal and are usually described as three dimensional.

Traditionally, a device known as a Gothic arch tracer has been used to record

mandibular movement in the horizontal plane. It consists of a recording plate

attached, to the maxillary teeth and a recording stylus attached to the mandibular

teeth. As the mandible moves, the stylus generates a line on the recording plate that

coincides with this movement. The border movement of the mandible in the

horizontal plane can therefore be easily recorded and examined.

When mandibular movements are viewed in the horizontal plane, a rhomboid-

shaped pattern can be seen that has a functional component, as well as four distinct

movement components.

1. Left lateral border

2. Continued left lateral border with protrusion

3. Right lateral border

4. Continued right lateral border with protrusion

Left Lateral Border Movements

With the condyles in the CR position, contraction of the right inferior lateral

pterygoid will cause the right condyle to move anteriorly and medially (also

inferiorly). If the left inferior lateral pterygoid stays relaxed, the left condyle

will remain situated in CR and the result will be a left lateral border movement (i.e.,

the right condyle orbiting around the frontal axis of the left condyle). Therefore the

left condyle is called the rotating condyle, because the mandible is rotating around it.

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Continued Left Lateral Border Movements with Protrusion

With the mandible in the left lateral border position, contraction of the left

inferior lateral pterygoid muscle along with continued contraction of the right inferior

lateral pterygoid muscle will cause the left condyle to move anteriorly and to the

right. Because the right condyle is already in its maximal anterior position. The

movement of the left condyle to its maximum anterior position will cause a shift in

the mandibular midline back to coincide with the midline of the face.

The right condyle is called the orbiting condyle, because it is orbiting around the rotating condyle. The left condyle is also called the working condyle, because~ it is on the working side. Likewise, the right condyle is called the nonworking condyle, because it is located on the nonworking'- side. During this movement the stylus will generate a line on the recording plate that coincides with the left border movement.

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Right Lateral Border Movements

Once the left border movements have been recorded on the tracing, the

mandible is returned to CR and the right lateral border movements are recorded.

Contracting of the left inferior lateral pterygoid muscle will cause the left condyle to

move anteriorly and medially (also inferiorly). If the right inferior lateral pterygoid

muscle stays relaxed, the right condyle will remain situated in the CR position. The

resultant mandibular movement will be a right lateral border movement (e.g., the left

condyle orbiting around the frontal axis of the right condyle). The right condyle in

this movement is therefore called the rotating condyle, because the mandible is

rotating around it. The left condyle during this movement is called the orbiting

condyle, because it is orbiting around the rotating condyle. During this movement the

stylus will generate a line on the recording plate that coincides with the right lateral

border movement.

Continued Right Lateral Border Movements with Protrusion

With the mandible in the right lateral border position contraction of the right

inferior lateral pterygoid muscle along with continued contraction of the left inferior

lateral pterygoid will cause the right condyle to move anteriorly and to the left.

Because the left condyle is already in its maximum anterior position, the movement of

the right condyle to its maximum anterior position will cause a shift back in the

mandibular midline to coincide with the midline of the face. This completes the

mandibular border movement in the horizontal plane.

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Lateral movements can be generated by varying levels of mandibular opening.

The border movements generated with each increasing degree of opening will result

in increasingly smaller tracings until, at the maximally open position, little or no

lateral movement can be made.

Mandibular movements in the horizontal

plane:- 1)Left lateral

2)Continued left lateral with protrusion

3)Right lateral

4)Continued right lateral with protrusion

CR– centric relation

ICP –intercuspal position.

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HORIZONTAL RELATIONS

Horizontal relations are those that are established anteroposteriorly and

mediolaterally and so are classified as:

Centric Relations

Eccentric Relations --- Protrusive Relations

--- Lateral Relations --- Right lateral

--- Left lateral

Centric Relation

Defined as the maxillomandibular relationship in which the condyles articulate

with the thinnest avascular portion of their respective discs with the complex in the

anterior –superior position against the slopes of the articular eminences.

Features and Significance Of Centric Relation

1. Centric relation is the ideal arch to arch relationship and an optimum

functional position of the jaws for the health, comfort and function of the

musculature.

2. It is a mandibular position where the condyle disc assembly is seated in

anterior superior position against the posterior slope of articular eminence, which was

believed by many to be the rearmost, upmost, midmost position in the glenoid fossa.

(RUM position).

3. Centric relation of the mandible is a hinge position. In Centric relation

condyles exhibit only pure rotation without translation.

4. Mandibular movements return or terminate in centric. It is thus a reproducible

position and therefore serves as a reliable reference to develop centric occlusion in

artificial dentures. It is a starting point for the arrangement of artificial teeth in

articulator to develop maximum intercuspation in complete dentures.

5. It is a position where upper and lower teeth are braced against each other

during deglutition.

6. It serves as a reference position for the occlusal reconstruction in dentulous

situations. It is the posterior border position and the posterior limit of the envelope of

mandibular motion.

To summarize Centric relation is a reproducible, recordable, consistent

reference position, and a physiologically acceptable position for deglutition.

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Recording Centric Relation in Edentulous Subjects

In edentulous subjects, centric jaw relation is generally recorded by

• Wax closure method

• Functional chew in technique

• Graphic method

• Anterior deprogrammers

Wax closure method of recording centric relation with swallowing, phonetics

and manual guidance is quick and a simple method.

The arrow point tracing method is a reliable and scientific procedure of

recording the mandibular border movements in the horizontal plane and captures the

mandible at its posterior reproducible border position.

Limitations of Wax Occlusal Rim Method to Record Centric Relation Inconsistency of the record: two centric records taken for the same patient may

not always be identical. Patient co-operation and operator-induced errors should be

considered.

Possibility of occlusal rims sliding over the other to any eccentric position either

before , during or after sealing the occlusal rims in centric relation.

Tilting, leverage and displacement of record bases is very common and this may

result in inaccurate centric record.

There is a tendency for the patient to bite and protrude the mandible. The term

bite registration is therefore objectionable and obsolete.

Eccentric Relations

Is defined as any relationship of the mandible to the maxilla other than centric

relation. The eccentric relations that are recorded and used in complete denture

construction are protrusive and right and left lateral.

Protrusive Relation is the relation of the mandible to the maxilla when the

mandible is thrust forward. If the motion in every part of the mandible as it is thrust

forward has simultaneously the same velocity and direction, the motion could be

correctly termed translatory. The movement in the joint is downward and forward.

The condyles disk assemblies are guided downward by the articular eminences of the

glenoid fossae. The angle of slide varies from patient to patient and from side to side.

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In the same patient, the muscles responsible for a straight protrusive movement are

the inferior pterygoid muscles acting simultaneously. Protrusive relation is a bone-to-

bone relation, which can be recorded.

Right and Left Lateral Maxillomandibular Relations are the relations of the

mandible to the maxillae when the mandible is moved either to the right or to the left

side. The movement of the mandible is the result of the contraction of contra lateral

inferior external pterygoid muscle. When the external pterygoid of one side contracts,

the corresponding side of the mandible is pulled forward and inward, while the other

side remains comparatively fixed. The side that is pulled forward is termed the

nonworking, balancing, or orbiting side, whereas the side that remains comparatively

fixed is termed the working, or rotating, side.

The movements in the non- working side are downward, forward, and inward.

The movement is both sliding and rotary. The movements in the working side are

rotational. The rotation may also be accompanied by a side shift. Lateral

maxillomandibular relations can be recorded.

The question of necessity for eccentric records is controversial, because

accuracy is a problem in the recording methods and the capabilities of the articulator

to receive and reproduce the record. The following factors contribute to inaccuracy:

(1) Instability of records,

(2) Resiliency and displaceability of denture-bearing tissues,

(3) Materials used in record, making,

(4) Equipment used in record making,

(5)Lack of muscle coordination in the patient, and

(6) The use of articulators that do not accurately adjust to all lateral interocclusal

check records.

The controversy about the merits of eccentric records will exist as long as

there are differences in the concepts of occlusion and posterior tooth form required for

complete dentures. Dentists who prefer a cusp form posterior tooth and balanced

occlusion in eccentric jaw positions or organic occlusion will require eccentric

maxillomandibular relation records. Dentists who prefer a noncusp form posterior

tooth and balanced occlusion in centric jaw position will not require eccentric

maxillomandibular relation records.

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There are no scientific data to support advantages of one concept over the

other. We do no know how much accuracy is required in many of the procedures in

complete denture construction to ensure success. Each situation must be analyzed, and

the method of choice is the method that is the most accurate.

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GRAPHIC METHOD The graphic methods record a tracing of mandibular movements in one plane,

an arrow point tracing. It indicates the horizontal relation of the mandible to the

maxilla. The apex of a properly made tracing presumably indicates the most retruded

relation of the mandible to the maxilla from which lateral movements can take place.

Graphic records are either intra oral or extraoral, depending on the placement

of the recording device.

Even though Balkwill, and Englishman, in 1866 illustrated the right and left

intersection arcs of lateral movement, it was Hesse from Germany, in 1897 introduced

the graphic method of recording centric relation, which was later popularized by the

Swiss professor Gysi in 1910. it became known as Gysi gothic arch tracing since it

resembled Gothic architecture characterized by high pointed arches.

The Glossary of Prosthodontic terms recommends central bearing tracing,

gothic arch tracing, needle-point tracing as the pattern obtained on the horizontal plate

used with a central bearing tracing device,

Central bearing tracing device is a device that provides a central point of

bearing or support between maxillary and mandibular dental arches. It consists of a

contacting point that is attached to one dental arch and a plate attached to the

opposing dental arch. The plate provides the surface on which the bearing point rests

or moves and on which the tracing of the mandibular movement is recorded. It may be

used to distribute the occlusal forces evenly during the recording of the

maxillomandibular relationships and /or for the correction of disharmonious contacts.

All movements in the horizontal plane initiate from the apex of the Gothic

arch. The apex of tracing is a reproducible reference point, which represents centric

relation. Gothic arch tracing ensures that the centric record is made with minimal

closing force equally distributed over the supporting tissues.

History The earliest graphic recordings were based on studies of mandibular

movements by Balkwill in 1866.

The first known "needle point tracing' was by Hesse in 1897 and the technique

was proved and popularized by Gysi around 1910.

Clapp in 1914 described the use of a Gysi-tracer, which was attached directly

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to the impression trays.

In 1926 Sears used lubricated rims for easier movement and placed the

needlepoint tracer on the mandibular rim and the plate on the maxillary rim. He

believed this made the angle of the- tracing more acute.

Philips in 1927 recognized that any lateral movement of the jaws would

cause interference of the rims, which could result in the distorted record. He

developed a plate for the upper rim and a tripoded balls bearing mounted on a

jackscrew for the lower rim. This was named the central bearing point, which

produced equalization of pressure on the edentulous ridges. .

In 1929, Stansbery introduced a technique, which incorporated a curved plate

with a 4" radius mounted on the upper rim-and. central bearing screw of 3% radius on

the lower rim. Plaster was injected after tracing was made.

HalI in 1929 use the Stansbery technique but he used compound as record.

Later graphic recording methods were developed which used the central

bearing point to produce the gothic arch tracing .

Hardy 1942 and Pleasure 1955 - described the use of the Coble balancer

The patient would hold the bearing point in the depression while plaster was injected

for the centric record. Pleasure1955 used a plastic disk, which was attached to the

tracing plate with a hole over the apex of the Gothic arch. The centric relation record

could then be made without a change of vertical dimension. and Hardy later

designed a modified intra oral trace similar to. the Coble.

Various tracing devices were later developed by Hight, Philips, Sears,

House, Messermann and others

The Sears Recording Trivet had an intraoral central bearing point and two

extraoral tracing plates.

Robinson designed the equilibrator in 1952 , a tracing device with a hydraulic

system and 4 bearing pistons, one each in the bicuspid and molar region. If: produced

a functional record of centric relation with a uniform distribution of stress over the

basal seat.

Silverman 1957 used an intraoral Gothic arch tracer to locate the "biting

point" of a patient. The patient was told to bite hard on the tracing plate. This

developed the functional resultant of the closing muscles, which would retrude the

mandible. The indentation made by the patient would be used for the centric record

whether or not it corresponded to the Gothic arch apex.

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Another change in the graphic method was using the central bearing as a tracer

to register intra oral gothic by Blanchad, Musseinan, Copie, Wastrow.

Hardy introduced a central bearing device with 2 heads. One end was brass

pointed and used in recording the tracing; the other end consisted of a mounted steel

ball bearing, which was used as an- anatomical teeth set to a flat plane of occlusion.

Various means of locking the tracer at the apex of the middle point tracing

have been described. These included (1) a hole or depression into which needlepoint

would fall also (2) a plastic metal disk with a hole, which was placed over the apex of

the tracing.

This served as convenience and a guide for the patient to hold .a centric

portion while the registration was secured by plastic needles techniques is an intra

oral registration. Technique in which 3 cutting pins were attached to spherical

occluding surfaces made with impression compound.

Height, Sears, House and many others who had devised tracing procedures of

their own which enabled them to secure dependable centric relation.

To make .a needlepoint tracing one condyle moves forward and inward during

a lateral movement followed by a movement in opposite direction with rotation

occurring around, the opposite condyle these movement cut lines extending to the

point representing the most retruded. portion of both condyles: Therefore when both

condyles are resting in the most retruded portion the needlepoint of the tracing will be

resting at the apex of the tracing thus created. A needlepoint tracing is fundamentally

a single representation of the portion of the mandible and its movements in a

horizontal plane.

Limitations Of Graphic Method

Gothic arch tracing method is preferred in good edentulous ridges with normal

interarch relation.

Arrow point tracing is difficult in excessively resorbed and flabby ridges as it

causes instability of the recording bases and this restricts its use.

Graphic method is not indicated when there is inadequate inter arch distance, as it

is difficult to accommodate the tracing device without increasing the vertical

dimension.

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A sharp arrow point cannot be traced in persons with TMJ arthropathy. In these

instances conventional wax closure method is the alternative choice.

Intra oral gothic tracing method is ideal in patients with habitual centric – A few

complete denture patients develop habitual centric either due to faulty centric relation,

or due to prolonged use of very old denture with marked attrition which causes a

forward habitual positioning of the lower jaw. This is a case of "habitual eccentric

occlusion". When the patient has worn inappropriate dentures for a long time, the

occlusion is habitually out of the centric occlusal position due to the functional

adaptation of the body in which one masticates in a position comfortable to

him/herself. In these patients it is difficult to record centric relation with wax closures

as they tend to move the jaw to habitual centric relation position, which is anterior to

the actual centric. The Gothic arch method is indicated in these patients. With intra

oral gothic arch tracing method, the stylus eliminates occlusal contact from occlusal

rims and therefore the habitual neuro-muscular memory or engram is absent. The

likelihood of sliding the lower jaw forward and laterally is hence eliminated.

Parts Of The Gothic Arch Tracer

The device used is called a gothic arch tracer which essentially consists of

1. A marking or recording and a tracing or recording table attached to the upper and

lower arches.

2. Stabilized base plates to prevent lateral movement and rocking thus ensuring

minimum errors in recording.

3 A central bearing device/screw to provide a central point of bearing or support

between the maxillary and mandibular occlusal rims. It consists' of a contracting point

which is attached to one occlusal rim and a plate attached to the other occlusal rims

which provide the surface on which the bearing point rests or moves without any

change in the vertical dimension. The device is placed at the central bearing point,

which is located as the center of the supporting areas of the maxillary and mandibular

jaws. It is used for the purpose of distributing closing forces, evenly throughout the

areas of the supporting structures during Recording of maxillary mandibular relations.

The central bearing helps to maintain the unstrained relation of the base plates

to the supporting mucosa, with an almost ideal distribution of contact pressure.

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Means of locking the tracer at the apex of the needle point tracing:-

1) a hole or a depression into which the needle point would fall.

2) a plastic/ metal disk with a hole which was placed over the apex of the tracing.

This served as a convience and as a guide for the patient to hold a centric position

while the registration was secured.

Positioning Of The Central Tracing Point

It is important to direct the force uniformly to the basal structures and thereby

ensuring stability of the base plates and uniform vertical contact.

The central bearing point can be placed at the midline of the upper arch at the

point where it is intersected by a line joining the distal surfaces of the second

premolars.

Stansberry has suggested placing the central bearing point at the point of

intersection of the lines drawn from the cuspid on the side to the second molar on the

other side.

Positioning the tracer (H.Villa)

The tracer is located in a vertical position in some procedures, while in others

it is at variable inclinations. To obtain correct Gothic arch tracing stabilized base

plates and central bearing point must be used and it must be perpendicular to condylar

hinge axis of mandible.

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Extra Oral Tracings And Devices

A Gothic arch tracing, as the name implies, is a pin-point tracing on soot or carding

wax that is shaped after a type of architecture known as the Gothic arch. It sometimes

is referred to as the arrow point tracing. When one condyle moves out in lateral, the

movement approximately rotates around the other condyle. This movement cuts a line

starting from a point, which is the most retruded position of the rotating condyle.

When the opposite condyle is caused to move on its path, it starts from the same point

and cuts a line at an angle to the other line. Therefore, when both condyles are resting

in their most retruded positions, the needlepoint of the' tracer will be resting on the

apex of the Gothic arch thus created.

A Gothic arch tracing is fundamentally a single representation of the position of

the, mandible and its movement on one plane. This statement should be modified if

several pins are used, such as the Sears trivet and further modified if the tracing is of

the type suggested by Phillips. The Phillips tracer indicates the condyle path as well

as the direction and centric position of the mandible.

Techniques Of Graphic Tracings

Gysi suggested 3 main point of movement of mandible namely, the 2 condyles

and the incisal point.

If a recording device is used to record the incisor point as the mandible is

moved laterally a V -shaped tracing is obtained. This is called by Gysi as the Gothic

arch. The apex of which is most retruded position of the mandible from which lateral

movements are made. Different technique was designed since 1910.

Extra oral:

1. Gysi tribyte - This technique omits the use of central bearing plates which

necessitates special care in establishing the contacting areas of the two bite plates.

Failure to produce equal contact over the entire occlusal area of the opposing bite

planes in centric-relation introduces tilting forces on the bases.

Gysi technique

In the original Gysi technique the occlusal plane is determined by locating the

correct height of the upper occlusion rim. Then the lower occlusion rim is adapted to

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the upper rim at the correct vertical dimension of occlusion. The Gothic arch tracer is

fixed to the upper rim at the occlusion rims with the tracing table paralell to, or

continous with, the plane of occlusion. The central beraing point is not used. No

mention is made of the inclination of the tracing point. No cusp height is introduced.

This means that even contact of the occlusion rims is lost when the patient makes

forward or lateral excursions of the mandible because of the forward and downward

movement of the condyles.

2. Sears Trivet

.

3. Stansberry cheek bite method - Stansberry developed and popularized the use of

central bearing point in connection with the tracing device for recording positional

relations of the jaw with the Stanberry’s cheek bite appliance records can be made of

centric jaw relations and protrusive relations. The tracing device is removable from its

attachment locations on the maxillary and mandibular bearing plates.

4.A Boos Bio-meter with tracing table and

marker is another extra oral method for

obtaining gothic arch tracing. The bio-

meter provides an indication of the portion

of the mandibular by tracing and records

the forces of closing. (The V.R. is adjusted

using biometer).

The Sears trivet is a central bearing

point tracer with two registration pins. The

pins are attached to the mandibular plate

therefore they will give a reverse gothic arch as

compared to those with the pin attached to the

maxillary plate. It traces 2 gothic arches

simultaneously. It has the facility of making

the records extra orally plaster of paris.

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5. Height tracer with central bearing point. Many extra oral technique using a central

bearing point has been developed such as scars trivet and terril. The Phillips Graphic

record registers the centric relation and the condylar paths.

6. Phillips tracer is another type of tracing device that registers centric relation and

the condyle path simultaneously.

The technique for an arrow point tracing using a Hight tracing device

1) Make accurate, stable maxillary and mandibular record bases.

2) Attach occlusal rims of hard base plate wax

3) Contour the wax occlusion rims

4) Establish the vertical dimension of jaw separation with the mandible at

physiologic rest.

5) Reduce the mandibular occlusion rim to provide excessive interocclusal

distance

6) Make a face bow transfer and mount the maxillary cast

7) With the soft wax make a tentative centric relation record at a predetermined

vertical dimension of occlusion.

8) Adjust the articulator with the condylar elements secured against the centric

stops

9) Relate the maxillary occlusion rims of the soft wax record and attach the

mandibular cast to the articulator with plaster.

10) Mount a central bearing device. Exercise care to center the central bearing

point in relation to the plate, both anteroposteriorly and laterally.

11) Mount the tracing device. Be sure to attach the devices securely to the

occlusion rims. The stylus is attached to the maxillary rim and the recording

plate to the mandibular. This arrangement develops an arrow point tracing

with the apex anteriorly. The reverse develops an arrow point tracing with the

apex posteriorly.

12) Seat the patient with the head upright, in a comfortable position in the dental

chair

13) Place the record bases in the patient’s mouth with the attached recording

devices. Inspect the record bases and the recording devices for stability. Make

sure that there is no interference between the occlusion rim when the mandible

is moved in any direction. Lower the stylus to the recording plate and

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determine that the stylus maintains contact with the recording plate during

mandibular movements.

14) Retract the stylus and conduct the training exercises with the patient. Place the

tips of the index fingers under the mandible in the bicuspid areas. Place the tip

of the thumb under the mandible near the chin. Calmly and quietly instruct the

patient to move the jaw forward, backward and to the right and left while

gently applying guiding pressure with the thumb. It is possible to dislodge the

mandibular record base by improperly placing the thumbs or by exerting

excessive pressure. The Ney Excursion Guide is an aid in training the patient.

15) When the patient is proficient in executing the mandibular movements,

prepare the tracing plate to record the tracing. A thin coating of precipitated

chalk in denatured alcohol applied evenly with a brush provides a medium that

offers no resistance to the movement of the stylus and produces a clearly

visible tracing.

16) Develop an acceptable tracing by dropping the stylus to the record plate.

17) When a definite arrow point tracing with a sharp apex is made, have the

patient retrude the mandible to centric relation. The point of the stylus should

be at the point of the apex of the arrow point tracing. Inject quick setting

dental plaster between the occlusion rims and allow the plaster to harden.

18) Remove the assembly and mount with the mandibular cast with the new

record.

19) This record is a tentative record and will be checked with an interocclusal

check record when the teeth are arranged and the wax is contoured.

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Stansberry Functional Position Check Bite Method

The appliance used consists of two bearing plates to which a stylus holder and

graph plate may be attached. A template for proper spacing of the bearing plates and a

glass syringe to aid in placing plaster.

1) The occlusal rims adjusted to the correct vertical relation

They are mounted on an articulator with the screw tightened to maintain the relation

of the casts.

2) The central bearing plates are placed in the template which has been placed on the

bite plates that had been shortened to provide space for it.

3) With the central bearing plates attached to the bite plates, the central bearing screw

is brought into contact and the tracing table and the stylus are attached.

4) A Gothic arch tracing is developed by the patient. This relation is maintained and

the plaster is injected when the plaster is injected. When the plaster has set the record

is marked and set aside for later use.

5) Accommodation for cusp height in lateral movements is accomplished by raising

the screw in the bearing plate by one and 1/2 turn. A second 9 inch is developed due

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to the increased vertical dimension. From the apex of this tracing a mark 1/4 inch or

6mm distant is made on each lateral path. This marks the position of the needle point

for lateral records.

6) The central bearing point is raised one half turn more for the protrusive

registration.

Classification Of Arrow Point Tracing

Gerber described six different types of Gothic arch tracings.

Typical – seen as a well-defined apex with a symmetrical left and right lateral

component. The mean Gothic arch angle is about 120 degrees. It reflects a healthy

TMJ without interferences in condylar path and a balanced muscle guidance. The

symmetrical form indicates an undisturbed movement of the condyle in fossa and

distal slope of eminence with symmetrically balanced muscle guidance.

Flat form – it is similar to typical arrow point except that it has more obtuse left

and right lateral tracings. This type of arrow point signifies a marked lateral

movement of condyle in the fossa. The Gothic arch angle is more than 120 degrees.

Asymmetrical form – the left and right tracings meet in an arrow point, however

their inclination to the protrusive path is not symmetrical

-- one of the lateral tracing is shorter. This form of tracing indicates an inhibition of

the forward movement, either in the left or right joint.

Apex absent /round form – instead of a sharp arrow point, the tracing is rather

round. It shows a weak retrusive movement. Tracing should be repeated till a definite

arrow point is obtained. Patient training is necessary.

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Miniature arrow point – similar to the typical arrow point, however the extension

of tracing is very limited. This can be due to restricted mandibular movements,

improper seating of record bases and painfully fitting record bases during registration.

It is also an indication of a long period of edentulousness with an inhibition in

condylar movements.

Double arrow point – it is a record of habitual and retruded centric relation.

Allow patient training and repeat till a single gothic arch is obtained. It is also seen

when vertical dimension is altered during registration.

Dorsally extended arrow point – the protrusive path extends beyond the apex of

the gothic arch. This signifies a forced strained retrusive movement of the lower jaw

either by the patient or the operator. During registration procedure lower jaw is either

forcibly retruded by patient (active retrusion) or forcibly retruded manually by the

operator (passive retrusion). It is sometimes an artifact caused by the forward

displacement of upper occlusal rim or backward dislodgement of the lower rim while

moving them in the mouth. The arrow point tracing is correct but at a particular stage

there was sliding of upper occlusal rim forward and lower displacing backward.

It can occur when the head of the patient is tilted too far posteriorly. Gerber felt that

occasionally the distal extension is correct, but the tracing was obtained with the

mandible in protruded position.

Interrupted Gothic arch – break or loss of continuity of lateral incisal path of

gothic arch. This happens due to posterior interference at heels of occlusal rims during

lateral movements.

Atypical form – protrusive component does not meet at apex but on one of the

lateral path. This may happen in dentulous because of faulty muscular pattern due to

parafunctional habits like bruxism. Also seen in very old edentulous patients, who are

using complete dentures with incorrect centric relation.

22

Evaluation of Gothic Arch Tracings

Classical, pointed form

The symmetry indicates an undisturbed

movement sequence in the joints and uniform

muscle guidance.

Classical flat form

The picture indicates distinct lateral

movements of the condyles in the fossae.

Weak Gothic arch tracing

The picture indicates a lax and negligent

performance of the movements, most of all of

the backward components. The registration

must be repeated: Stronger movements must be

demanded from the patient.

Assymmetrical form

The tracing indicates a distinct inhibition of the

forward movement in the right joint.

Miniature Gothic arch tracing

The tracing points to cramp-like movements,

badly fitting and pain-causing record blocks,

edentulous state of long standing with inhibited

movement in the joints, badly constructed

prosthetic appliances, etc.

Vertical line protrudes beyond the arrow

point

This tracing was produced either by forcible

retraction or pushing of the mandible. It is,

however, possible that the Gothic arch was

obtained with a protruded mandible.

23

Vincent R Trapozzano: An analysis of current concepts of occlusion: JPD:

1955:5 764-782

When making a tracing for establishing centric relation on a patient with a

normal temporomandibular joint, the apex of the initial tracing will be mounted

frequently instead of having a definite apex. Aside from the technical factors the

rounded apex may result from the patient’s failure to understand what is required

when the right and left lateral movements are made, habit or a slight filling in of

tissues behind one or both of the condyles.

With some persistence on the part of the patient and operator, the patient may

produce a needle point tracing with a definite apex. Sedation may be indicated to

relax the patient.

Suppose the blunted apex of the needle point tracing had been accepted as the

position of centric relation, and that occlusal reconstruction, correction of occlusal

disharmony of natural teeth, or denture reconstruction had been completed. With this

as the starting point , the results would be disastrous. In occlusal reconstruction, or

correction of occlusal disharmony, a definite malocclusion would result whenever the

patient decided to close in the more retruded position (at the apex). In complete

denture construction , the resulting area of malocclusion would produce an inevitable

shifting and sliding of the denture bases, which would result in instability of the

dentures and all of its undesirable sequalae.

Since it is recognized that the individual will undoubtedly make many initial

tooth contacts which vary from the most retrusive position (at the apex) to a slightly

anterior (eccentric) position (on the blunted apex), provision must be made to avoid

“grooving” the patient to the most retruded position before inclined plane contact is

made. If the cusp teeth are used, this is accomplished by allowing for “free play”, a

slight widening of the central grooves or fossa of the posterior teeth is made to

provide an area larger than the size of the cusp which fits into the groove or fossa

when initial tooth contact is made. Thus, provision is made for a limited range of

horizontal movement of the mandible without engaging the inclined planes of the

teeth.

Howard F. Smith: A comparison of empirical centric relation records with

location of terminal hinge axis and the apex of the Gothic arch tracing ; JPD 1975 :

33:511-520

A class III jaw relationship classically exhibits little anteroposterior

24

movement, while a class II exhibits much. One may suggest little importance for

anteroposterior precision, while the other may suggest great importance. An arthritic

patient may exhibit limited movement in either direction.

Significance Of Gothic Arch Tracing

It is important not to accept any other part of the tracing except the very apex

as an indication of centric relation. When the patient chews lightly, they may often

close their jaws in eccentric positions. However, patients will pull the mandible to

complete retrusion many times under heavy closing pressure exerted during function

of mastication. Therefore if the dentures are not constructed with centric occlusion in

harmony with centric relation, the teeth will not contact evenly when under

considerable closing pressure. This uneven or premature contacting is a disturbing

factor in the retention and stability of dentures, and it can cause soreness of the tissues

supporting the dentures. On the other hand, if centric occlusion is in harmony with

centric relation, the patient can function properly with his mandible in all positions

under light and heavy chewing pressures.

Extra oral tracings made without a central bearing point are not considered

satisfactory because although they indicate the correct anteroposterior position of the

mandible, they may not record the correct maxillomandibular relation (superioinferior

relation of the jaw). It is extremely difficult to maintain equalized pressure on the

blocks of wax. Therefore there is not much to be gained by securing a tracing without

using a central bearing point.

Significant Points In Making A Gothic Arch Tracing

1. Displacement of the record bases may result from pressure, if the central bearing

point is off center when the mandible moves into eccentric relation to the mouth.

2. If a central bearing device is not used the occlusal rims offer more resistance to

horizontal movements.

3. It is difficult to locate the center of the arches to centralized the forces with a

central bearing device when the jaws are in favorable relation and far more difficult if

the jaws are in excessive protrusive or retrusive relation

4. It is difficult to stabilize a record base against horizontal forces on tissues that are

pendulous or other wise easily displaceable.

25

5. It is difficult to stabilize a record base against horizontal forces on residual ridges

that have no vertical height.

6. It is difficult to stabilize a record base or bearing device with patients who have

large tongues.

7. Recording devices are not considered. Compatible with normal physiologic

stimulation in mandibular movements.

8 The tracing is not acceptable unless a pointed apex is developed, a blunt apex

usually indicates an acquired functional relationship.

9. Double tracing usually indicates lack of coordinated movements or recording at the

different vertical dimension of jaw separation. In. either events additional tracing

should be made.

10. A graphic tracing to determine centric relation is made .at a predetermined vertical

dimension of occlusion. This harmonizes centric relation with centric occlusion and

the antero-posterior bone, to bone relation with the tooth - tooth contact.

11. Graphic methods can record eccentric relation of the mandibular to the maxillary.

12. Graphic methods can be considered the most accurate visual means of making a

centric relation record with mechanical instrument, however all graphic tracings are

not accurate.

Intra Oral Tracing Device

Intra oral tracings combine a central bearing point with a pinpoint tracing. The

bearing point is pointed and records a tracing on the opposing plate. A hole is drilled

in the plate at the apex of the Gothic arch in some techniques that employ intra oral

tracing devices. This hole or depression is used to hold the patient in this retruded

position while the registration is being recorded with plaster or some such material.

The Seidel, Ballard and the Messerman tracers are examples of intraoral tracing

devices. . Another type of intraoral registration is afforded by the Needles technique

in which three pins attached to the maxillary rim, one in the anterior portion and one

on either side in the posterior region, register the movements of the mandible by

means of three Gothic' arches. , They indicate both the centric position and the

condylar paths eccentric.

Needles described the operation as follows:.

To form the occlusal rims adapt a. baseplate to the model and attach a roll of

26

soft modeling compound to form a bite rim. Grease the spherical plate and press it to

position thus molding a spherical surface on the lower bite rim at the de-sired

position. Trim the bite rim to the proper contour and by trial in the patient's mouth

ascertain whether the position and direction of this surface are as desired, and correct

any errors. Now chill the rim and lubricate the occlusal, surface with Vaseline- Soften

the opposing bite rim by heating and take the bite in the usual manner. In this way

produce the opposing spherical surface upon it. Chill both plates and trim away

surplus- material so that only the opposing spherical surface remains. Trim the

periphery to the contours desired in the finished dentures. If these procedures have

been carried out properly, when the bite plates are placed in the patient's mouth, the

mandible may be moved in every occlusal position, producing little, if any, separation

at any part of the bite rims.

Three pieces of wire are now imbedded in the rim of the upper baseplate. One

end of the wire is heated and forced into the modeling compound in the incisal region

and the soft compound is packed firmly about the base of the wire. A wire is similarly

placed on each side about the position of the distal side of the first molar. The wires

are then cut off about 1.5 mm. above the surface of the bite rim. The incisal wire

should strike the lower bite rim near the anterior border with the plates in centric

occlusion, and the molar wires should strike slightly outside the middle of the lower

bite rim, so that the tracing will not run off the edge of the lower bite rim. Each of

these wires acts as a stylus to trace the paths of the respective points upon the surface

of the lower bite rim.

The insides of the bite plates are dusted with powdered gum tragacanth to help

maintain them firmly on the ridges. They arc then placed in the patient's mouth and

the patient is requested to close until one or' more of the pins come into light contact

with the lower bite rim. The patient is then asked to move the mandible forward and

back in the median line, maintaining a light pressure on the bite rims, the pins come

into equal bearing and each cuts a record of its path in the lower bite rim, which gives

the path of straight protrusion. Before these paths are cut too deep, the patient is

requested to retrude the mandible to its fullest extent and slide it to one. Side and back

again, slight contact of the pins being maintained. This movement is repeated a few

times and then the same is performed on the opposite side. Thus the three; paths are

deepened evenly, thoroughly cut to the full depth of the respective pins; in this way a

27

balanced three point contact -has been maintained and the path of each point has been

recorded for protrusion and for working bite on each side, while any separation that

has taken place between the bite rims at any point during these movements has been

recorded by a shallower tracing at that point. The form of the tracings will be found

the same as Gysi's three-point tracing. The depth of the tracings also gives a record of

the vertical relations. When the three pins arc in the anterior angles of their respective

tracings, the bite plates are accurately held in centric occlusion without the need of

guide lines.

The Needles technique modified by the use of a Messerman central-bearing point

tracer is suggested by Frahm

In this procedure the occlusion rims are constructed in exactly the same

manner as was described by Needles. Four pins are, attached in the first bicuspid and

second molar region' on the right and left sides of the maxillary occlusion rims. By

placing the pins in this position we are enabled to cut away the anterior portion of the

maxillary occlusion rim to provide a window for observing the tracing appliance. The

stylus portion of the tracer is attached to the vault of the maxillary trial base by

imbedding the tripod prongs into Compound or wax.

The graph plate is attached to the mandibular rim flush with the occluding

surface of the rim. The two units should be mounted in a manner, which will permit

the point of the maxillary appliance to rest near the center of the mandibular graph

plate.

The relationship plates are returned to the mouth, and the screw on tilt

maxillary appliance is adjusted so that it makes contact with the graph plate

simultaneously with the contact of the maxillary occlusion rim pins on the mandibular

occlusion rim. The patient then is instructed to make lateral and protrusive

movements. As the pins scribe the Gothic arches on the mandibular rim, the vertical

dimension is diminished a little at a time by means of the setscrew on the maxillary

appliance. This is continued until the surfaces of the occlusion rim make contact.

28

Coble Intra Oral Tracing Device

Coble Balancer is a type of intraoral central bearing device. The central

bearing point is attached with modeling compound to the upper base plate in the

center of the palate at the intersection of the midline and a line joining the centers of

left and right chewing areas.

When placed in the mouth, the upper and lower base plates make contact only

through the central bearing point at or very near the center of the supporting areas of

the upper and lower ridges.

The central bearing screw is raised or lowered to establish the vertical

dimension that provides an adequate free way space and the clearance between the

base plates at the distal borders is checked.

29

At the chosen vertical dimension, the central bearing point, acting as a stylus,

quickly draws a Gothic arch tracing as the patient performs excursive gliding jaw

movements. To lock the patients jaw in centric relation at the apex of the Gothic arch

tracing without changing the vertical dimension, use a thin sheet about 1mm of clear

Lucite as an overlay, and drill a small hole through it down to, but not into, the

aluminum graph plate. The patient is then asked to perform a gliding jaw movement

and to stop when the central bearing point drops into the hole which was drilled over

the apex of the tracing.

At the time of insertion of the processed dentures, the Coble Balancer is used

again to integrate the gliding movements of the jaw with the occlusion of the teeth, to

perfect occlusal balance, and to eliminate cuspal prematurities and collisions. At first

the central bearing screw is adjusted to keep all teeth out of contact in all gliding

movements. With the sole point of contact between the upper and the lower dentures

located where the central bearing point touches the graph plate, the patient can

perform jaw movements that are uninhibited by occlusal interferences. And a Gothic

arch tracing is quickly scribed. The central bearing screw is shortened by half turn

(0.5mm) at a time until a tooth to tooth contact occurs somewhere on the arch during

the excursive gliding movements. Usually the first contact occurs on one or both

second molars or on the canines. Sometimes it occurs between the denture bases

behind the second molars if the interridge space is small. These occlusal contacts

occur while the remaining teeth are still held out of contact by the central bearing

point. They are treated as functional prematurities, and are ground down until they no

longer interfere. The central bearing point is then shortened by one-fourth turn, and

30

articulating paper is reinserted to mark the contact areas during the jaw excursions.

All the prematurities are thus located, marked and reduced until the majority of the

teeth make contact during the gliding movements, with the central bearing point still

riding on the graph plate.

Hardy and Porter made a depression on the tracing plate with a round bur at the apex

of the tracing. The patient would hold the bearing point in the depression while plaster

was injected for centric record.

Hardy introduced a central bearing device with 2 heads. One end was brass

pointed and used in recording the tracing. The other end consisted of a mounted steel

ball bearing which was used as an anatomic teeth set to a flat plane of occlusion.

Pleasure improved this technique by using a hole which was attached to the tracing

plate after the tracing was made, with the hole coinciding over the apex of the Gothic

arch tracing. The central bearing point was held in a hole when a plaster was injected

the centric would then be made without a change of vertical dimension.

Ballard Intra Oral Tracing Device

1. Palatal bearing plate 2 .rounded head of correlator pin 3. Tension spring 4.

Adjustable screw 5. Mounting plate 6. Pointed end of correlator pin

Metal points attached to the upper modeling compound rim will cut pathways

in the occlusal surface of the lower modeling compound rim as the patient moves the

mandible from side to side. Apex of the tracings facing anteriorly indicates the most

posterior position of the mandible during chew in procedure. The pathways running

31

laterally from the apex indicate the direction of lateral mandibular excursions and the

pathways running posteriorly indicate protrusive mandibular excursions.

Advantages and Disadvantages

1) The intra oral tracing device has less assembly. Hence it is more comfortable

for the patient. Also it makes the procedure of assembling the device and

recording procedure easier for the operator.

2) Since the intra oral tracing are small, it is difficult to find the apex compared

to the extra oral tracing.

3) The tracers must be definitely seated in the hole made by a round bur to assure

accuracy when plaster is injected between the rims. Any shift in the position of

the stylus from the position of the apex of the tracing cannot be prevented or

corrected when plaster is being injected. Since any shift made is not seen and

the procedure has to be repeated.

4) The intra oral tracings cannot be observed properly during the tracing

procedure and hence the method loses some of its value.

Precautions

Displacement of record bases may result from unequal forces. If the central

bearing point is not properly centralized. In case of unequal jaw sizes,

centralization should be done with respect to the lower rim.

Tracing with a blunt apex should not be accepted because a blunt apex usually

indicates an acquired functional relationship of the mandible to maxilla and only a

sharp apex indicates the point of centric relation.

It is difficult to stabilize a record base on residual ridges that have no vertical

height, that have flabby tissues and in case of patient with large tongue.

Comparison Between Intra Oral And Extra Oral Devices

HEARTWELL states that intraoral tracings cannot be observed during tracing;

therefore the method loses some of its value of a visible method. Since the intraoral

tracings are very small, it is difficult to find a true apex. The tracer must be seated in a

hole at the point of the apex to assure accuracy when recording the relation. If the

patient moves the mandible before the occlusal rims are secured, the records shift on

their basal seat, this destroys the accuracy of the record.

32

The extra oral tracings are larger and therefore the patient can be directed and

guided more intelligently during the mandibular movements. The stylus can be

observed in the apex of the tracing during the process of injecting the plaster between

the occlusal rims and recording the relation and no holes are required. Boucher prefers

the extra oral device.

BOUCHER also recommended that centric relation should be made with

minimal pressure to prevent displacement of the tissues supporting the bases, in order

to achieve uniform simultaneous contact of the dentures.

SOLOMON claimed that in intraoral method the errors are likely to be less

because the tracing is situated closer to the centers of movements in the

temporomandibular joint in comparison to the flexible extra oral device which

inscribes mandibular movement in a plate situated outside the mouth further away fro

the centers of mandibular movement. Further the presence of extra oral tracer

attachments prevents the lips from meeting each other and remains passive.

According to him , the distinct advantage of intraoral tracing is the ability of the

subject to perform mandibular movements with the lips in passive contact position.

KAPUR K K and YURKSTAS A A (1957) compared the duplicability of records

using various techniques

The intra oral tracing procedure (hardy)

The wax registration procedure (hanau)

The extra oral tracing procedure (stansberry)

They concluded that The intra oral and extra oral procedures were more

consistent compared the wax registration method The intra oral and extra oral

procedures became less consistent in patients with flabby ridges as compared to

patients with good and flat ridges The consistency of the extra oral procedure did not

vary significantly with different types of ridges The degree of consistency with the

intra oral procedure decreased to a significant level in patients flabby ridges The wax

method was less consistent than the other two procedures. It showed least consistency

on flat ridges and the highest consistency on flabby ridges

R.H. KINGERY (1952) reviewed the problems associated with centric relation which

were

33

Problems of Requirements

Recording the correct anteroposterior or horizontal realtionship of the

mandible to the maxilla in a position.Equalization of contact on the denture

supporting areas – Equalization of vertical contact

Problems of Errors

Positional Errors caused by

Failure of the operator in his registration of the correct horizontal relationship.

Failure of the operator to record equalized vertical contact

Application of excessive closure pressure by the patient at the time of

recording

Changes in the supporting areas

Technical Errors may be caused by

Ill fitting occlusal rims

üIndiscriminate opening or closing of the occluding device or articulatorThe

slight shifting of the teeth which occurs between the stage of final arrangement

and the transfer to a permanent base material.

Problem Of Recognizing The Symptoms Of Errors Associated With Centric

Realtion

Symptoms Of Unequalized Vertical Contact

Loss of retention

üIrritation on the crest of the lower ridge in the area of premature contactOne

tooth or several teeth on one side seem too long to the patient or seem to strike

first

The patient may complain of clicking if the teeth are porcelain

premature contact anteriorly or posteriorly

Symptoms Of Error In Horizontal Relationship Anterior to CR

o Looseness of lower denture

o denture consciousness

o Irritation under the anterior lingual flange of the lower denture

Symptoms Of An Error In Horizontal Relationship Posterior to CR

• Looseness, especially of lower denture

• Irritation under the anterior labial flange of the lower denture (occasionally)

34

Problems Of Recording Centric

1. The correctness of an individual registration is never assured until it is

checked and verified by the observation of the operator

2. Methods Of Recording Centric

• Limitations of Graphic recording

• No control over the amount of closure pressure

• Difficulty in placement of central bearing point when patients present extreme

protrusion or retrusion of the mandible

• Central bearing point is troublesome to use when patients present large clumsy

tongues, extreme resorption of ridges or extensive amounts of displaceable

tissues on the supporting areas.

35

REVIEW OF LITERATURE

In 1910 –Gysis stated needle points tracing has been accepted as an accurate

method of locating the centric maxillomandibular relation at a given degree of jaw

separation.

In 1940 – Boos in his study in maxillomandibular relations established by

biting power stated in his research on maxillomandibular relationship with the use of

the power point, reports that centric relation is not at the apex of the gothic arch. He

stated that he found by use of resultant biting power (point) that the needle point

tracing is extremely accurate in some patient and in others it is unreliable, the

resultant biting point is located at apex of the needle point tracing in some patient,

anterior to the apex in others.

In 1947 – Apriele H and Saizer P in their publishing on gothic arch tracing and

tempero mandibular anatomy stated that needle point tracing is the most accurate

method of determining the centric relation.

In 1952 – Granger stated that the apex of the Gothic arch tracing shows a

sharp apex. It does however have one value. In order to do an accurate tracing it is

necessary to do two tracing one on each side of the mandible.

In 1952 – R H Kirgery conducted a review of some of the problems

associated with centric relation. In this he groped these methods and attempt to

review their limitation and possibilities.

1. Graphic recording method employing a arch or tracing as guide for check

bite.

a. E O T P

b. I O T P

2. Function recording

3. Direct check bite recording.

In 1954 – Sicher in his study on positions and movement of the mandibular

that centric relation is the ideal position which coincides with the median occlusal

position.

36

In 1954 – Stansbury proposes a method to check the correctness of the central

bearing position is the ideal position which coincides with the median occlusal

position.

In 1954 – Stansbury proposes a method to check the correctness of the central

bearing position. One rod it passed through the a needle holder and other placed on

the tracing plate. They should be parellel in all directions.

In 1955 - Max a pleasure in his article occlution of cuspless teeth for balance

or comfort has elaborated that the central bearing screw is raised or lowered to

establish the vertical dimension that provides an adequate freeway space. At a chosen

vertical dimension the central bearing point acting as a stylus quickly gliding jaw

movements. To lock the patients jaw in centric relation at the apex of the gothic arch

tracing without changing the vertical dimension we us a thin sheet (about 1 mm) of

clear Lucite as an overlay and drill a small hole through it down to the aluminium

glass plates. The patient is then asked to perform. A gliding movemento to jaw and to

stop when the central bearing point drops into the hole at the apex of the tracing.

In 1955 – Vincent R Trapozzano in his article on an analysis on current

concepts of occlution defined centric relation as the most retruded unstrained position

of the condyle in the Glenoid Fossae at any given degree of jaw separation from

which lateral. Movements can be made. Centric relation is a condyle fossae

relationship.

The logic for the selection of the most retruded unstrained position as the

starting point for the correction of malocclution. Occlusal reconstruction and denture

reconstruction can be easily demonstrated by means of needle point tracing.

When making a needle point tracing for establishing centric relation on a

patient with normal temperomandibular joint the apex of the initial tracing will be

rounded frequently instead of having apex and the objective is reached only after

several appointments.

A B

The blunted apex usually Properly apexed tracing

Obtained in an initial

Attempt to make a tracing.

37

In 1957 – Muyer M Silvermann on his article centric occlution and jaw

relation and fallacies of current concepts writes the method of determining the

horizontal relation of the mandible. to maxillary in centric maxillomandibular relation

in through functioning of the closing musculature.

Kurth shows that the resultant direction into centric occlution from a

functional chewing strokes is always forward and upwards.

In 1959 – Honorotu Villa in his article gothic arch tracing has summarized in

his study of gothic arch tracing made by intra oral and extra oral methods was made,

different inclination of the extra oral tracer were used.

To obtain correct gothic arch tracing stabilized base plates and central bearing

point must be used and it must be perpendicular to condylar hinge axis of mandible.

In 1959 – Elmer E Francis in his article jaw relation in C D construction described

vertical tracer is that which registers and determines the proper vertical dimension,

centric relation and condyle path records. This vertical dimension is result of study of

Gysi. Horizontal position of the mandible is registered by the gothic arch tracing.

Vertical tracer consist of upper and lower metal plate which are shaped like balanced

occlusal guide plates. These two plates are attached to upper and lower base plates,

upper plate has a vertical plate and a gothic arch tracer. The lower plate has a

horizontal tracing table, an intra oral removable screw attachment that constitute

vertical stop and slip joints which holds Gysi face bow and a vertical marker.

In 1961 – Huges and Regli : In his study of what is centric relation observed

that a sharp gothic arch tracing may be obtained with the condyles in more than one

location in the glenoid fossa.

When using a central bearing point for patients with prognathic or

orthognathic occlutions it is difficult, not if possible to secure equalization of

pressure.

In 1961 – Honorotu Villa : In his article circulars rotation in mandibular

movement summarized the geometric representation of the mandible and its

movements are explained. A simple method of locating hinge axis and correlating the

circular opening movement and the lateral movements of the mandible has been

described.

38

In 1962 – Jones PM : In his study of eleven aids for a better CD stated in intra

oral gothic arch tracer is used to determine the centric relation at the established

vertical relation. The needle point tracing device is a reliable, accurate and practical

method for locating centric relation. The apex of a tracing is indented with a bur. A

plaster intra occlusal record is made by injecting plaster into the patients mouth with

the stansbury plaster syringe.

In 1964 – Kapur and Yurkstas : Based on the study on 35 edentulous patients

using two centric relation recording procedures – Wax recording procedure and intra

oral procedure. In intra oral tracing procedure they found that the degree of variation

in subsequent recording can be kept at a minimum of the central bearing point and the

inclination of the tracing plate was accurate.

In wax recording procedure minimum closing pressure is exerted and occlusal

forces should be centralized and equally disturbed.

In 1965 – Mohammed A, W Arthur George and Russel H Scott : Article

evaluation of the needle point tracing as a method of determining centric relation

summarized.

1. Needle point tracing were obtained from ten subjects at five different degree

of jaw separation.

2. Two subject showed negligible lateral deviation at any degree of opening

when one subject showed consistant deviation from midline when the vertical

dimension between the jaw was increase

3. The needle point tracing at a given vertical dimension of jaw separation under

same controlled condition, on the same individual at same sitting were not

significantly different. So needle point tracing is reliable.

In 1965 – Mohammed A, EL Aramany, Arthur and Scott concluded in a study

on dentulous subjects to evaluate the graphic tracing procedure as a method for

determining the centric relation. Extra oral needle point tracing was obtained from 10

subjects at five different levels of jaw separation. At a given vertical dimension of jaw

separation, under controlled condition there were not significantly different. Hence

the needle point tracing is a reliable technique.

In 1968, Joseph E Grasso and John sharry in the study of the duplicability of

arrow point tracing in dentulous patients did a study with 15 white men (Detail

39

students between age group of 20 – 35) tracing were obtained at a fixed vertical

dimension for each subject. The vertical jaw separation varied from subject to subject

depending upon the cuspal teeth height of the posterior teeth and or the vertical

overlap of the anterior teeth.

Variation pattern of the apex position of the needle point tracing were greater

in an anteroposterior direction than in a mediolateral direction.

In 1969 – A langer and J. Michmann studying the intra oral technique for

recording vertical and horizontal maxillomandibular relation in complete dentures

wrote that the instrument used the Barnae stylus tracer is an intra oral tracing device.

This technique is recording vertical and horizontal maxillomandibular relation is

suggested. This technique fulfils basic requirements for correct complete denture

construction. This physiologic rest position is used as a reference for establishing an

acceptable interocclusal distance and the most retruded mandibular position is

recorded in centric relation. The use of central bearing point ensures equal distribution

of pressure throughout the basal seat while the records are made.

In 1970 – Clayton, Kotowiez and Myers : conducted a research on graphic

recording of mandibular movements concluded the orientation of styli and recording

table affected graphic tracing of mandibular movements. when the vertical dimension

is changed, cusp gliding on inclines involves change in vertical dimension.

In 1975 – Smith in study in comparison of empirical centric. Relation record

and location of terminal hinge axis and apex of the gothic arch tracing concluded that

average empirical determination provided a centric relation point anterior to that

determined by either the gothic arch and the hinge axis location . Gothic arch

method was the most repeatable of the three methods.

In 1980 – in his article relation of gothic arch apex to dentist assisted centric

relation concluded that thumb pressure can position the mandible consistently more

posterior than the position indicated by the gothic arch apex is unfounded. It also

states that dentist assisted jaw relation is more reproducible than relation indicating

gothic arch apex. (Micheal Myer).

In 1982 – C Brusgagin, S Carrosa, G Preti and R Scotti ; in his clinical study

of graphic registration of condylar path inclination summarized the angular values of

the condylar sagittal pathway registration from 390 patients and obtaining by tracing

40

to the graph with the graphic recording was analyzed. The data subjected to statistical

analysis give a median angular value of the condylar sagittal pathway equal to 33

degree and showed a great median value dispersion. The angular value of condylar

sagittal pathway was repeated over time since variation found less than 5 degree were

noted after repeatable registration in patients and temperomandibular joint

disturbances as well as in patient treated with complete denture.

In 1986, James W Robbinson; in his article central bearing device for the

dentulous patients with few or no posterior contacts.

In 1987 – Winstanly : In his article gothic arch tracing and condylar

inclination concluded that records and the patient referred for treatment of

temperomandibular joint disorders were used to compare condylar inclination found

by drawing a Tanjent and by using a mathematical technique. Needle point tracing

angles were also measured for the same patient and were compared with the condylar

inclination. It can be concluded that the mathematical technique outlines records a

more accurate value between patient and L & R sides of the same patient and there is

no direct relationship between condylar inclination and the needle point tracing

angle.

In 1989 – Winstanly : in his article the gothic arch tracing and the upper

canine teeth as guide in the positioning of the upper posterior teeth concluded that the

relationship between the position of the buccal cusps of the natural upper posterior

teeth and the distance between the upper canine teeth has been found to be constant

within + 1-2mm this may be of value when setting up artificial teeth for denture

patients, enabling them to be positioned close to the natural predessors.

1987 el-Gheriani AS, Winstanley RB. The records of 11 patients referred for

treatment of TMJ disorders were used to compare condylar inclination found by

drawing a tangent and by using a mathematic technique. Needle point tracing angles

were also measured for the same patients and were compared with the condylar

inclination. It can be concluded that (1) the mathematic technique outlined records a

more accurate condylar angulation, and (2) there is a great variation in condylar

inclination values between patients and between left and right sides of the same

patient, and (3) there is no direct relationship between condylar inclination and the

needle point tracing angle.

41

1988 el-Gheriani AS, Winstanley RB. Twenty-five subjects of three nationalities

carried out Gothic arch tracings. Measurements between the side arms were compared

with the upper intercuspid distances measured in the same subjects. A relationship

was found which may be of value in the setting up of anterior maxillary denture teeth.

1989 el-Gheriani AS, Davies AL, Winstanley RB

The relationship between the position of the buccal cusps of the natural upper

posterior teeth and the distance between the lateral arms of the Gothic arch tracing or

the distance between the upper canine teeth has been found to be constant to within

+/- 2 mm. This may be of value when setting up artificial teeth for denture patients,

enabling them to be positioned close to the natural predecessors.

1996 Obrez A, Stohler CS Perceived changes in occlusion and decreased range of

motion are often expressed by patients with masticatory muscle pain. The adverse

loading of craniomandibular tissues that results from an inadequate

maxillomandibular relationship in combination with the coexisting dysfunction is

widely regarded as the cause of pain. This study was designed to test whether pain can

cause significant changes in position of the mandible and therefore form the basis for

any perceived changes in the maxillomandibular relationship. A second objective was

to determine whether pain can cause changes in the mandibular range of motion. Five

subjects who rated pain intensity on a visual analog scale were used in a single-blind,

randomized, repeated-measures study design. Tonic muscle pain was induced by

infusion of 5% hypertonic saline solution into the central portion of the superficial

masseter muscle. Isotonic saline solution was used as a control, with subjects blinded

to the type of substance given. The effect of pain on the position of the apex of the

gothic arch tracing, the direction of the lateral mandibular border movements, and the

mandibular range of motion was studied in a horizontal plane with minimal occlusal

separation. Pain significantly affected the position of the apex of the gothic arch

tracing in anterior (F = 11.46, p = 0.03) and transverse (F = 35.0, p = 0.004)

directions. Similarly, pain affected the orientation of the mandibular lateral border

movements (F = 12.44, p = 0.02) and their magnitude (F = 14.97, p = 0.01). All pain-

induced effects proved to be reversible. The observed effect of pain can explain the

perceived change of bite that is frequently noted by patients with orofacial pain. This

42

study provided evidence of an alternative causal relationship between pain and

changes in occlusal relationship and questions occlusal therapy as treatment, directed

toward the elimination of the underlying cause in patients with masticatory muscle

pain.

1998 Raigrodski AJ, Sadan A, Carruth PL Clinicians have long expressed concern

about the accuracy of the Gothic arch tracing for recording centric relation in

edentulous patients. With the use of dental implants to assist in retaining complete

dentures, the problem of inaccurate recordings, made for patients without natural

teeth, can be significantly reduced. This article presents a technique that uses healing

abutments to stabilize the record bases so that an accurate Gothic arch tracing can be

made.

1999 Watanabe Y Analyzed and evaluated the horizontal mandibular positions

produced by different guidance systems. Twenty-six edentulous subjects with no

clinical evidence of abnormality of temporomandibular disorder were selected.

Horizontal position data for the mandible obtained by gothic arch tracing was loaded

into a personal computer by setting the sensor portion of a digitizer into the oral

cavity to serve as a miniature lightweight tracing board. By connecting this with a

digitizer control circuit set in an extraoral location, each mandibular position was

displayed in a distinguishable manner on a computer display in real time, then

recorded and analyzed. The gothic arch apex and tapping point varied, depending on

body position. In the supine position, the gothic arch apex and the tapping point were

close to the mandibular position determined by bilateral manipulation. This system

provides effective data concerning mandibular positions for fabrication of dentures.

2003 Keshvad A, Winstanley RB. conducted to determine statistically the most

repeatable mandibular position of 3 centric relation methods. Three centric relation

recording methods commonly reported in the literature were selected: bimanual

mandibular manipulation with a jig, chin point guidance with a jig, and Gothic arch

tracing. Fourteen healthy adult volunteers (7 males and 7 females), with an average

age of 26.61 +/- 4.20 years and no history of extractions, temporomandibular joint

dysfunction, or orthodontic treatment, were selected for the study. Accurate casts

were mounted on an articulator (Denar D4A) by means of a facebow and maximum

43

intercuspation silicone registration record. A mechanical 3-dimensional mandibular

position indicator was constructed and mounted on the articulator enabling the

operator to analyze the mandibular positions in 3 spatial axes (x, anteroposterior; y,

superoinferior; z, mediolateral shift). Each centric relation method was recorded four

times on each subject (at baseline, 1 hour, 1 day, and 1 week at approximately the

same time of day). Records were transferred to the articulator, and data were extracted

using a stereomicroscope modified to accept the mandibular position indicator. The

results of this study showed that of the 3 centric relation methods evaluated, the

bimanual manipulation method positioned the condyles in the temporomandibular

joint with a more consistent repeatability than the other 2 methods, whereas the

Gothic arch was the least consistent method.

44

REFERENCES

1. El-Gheriani AS, Winstanley RB. The Gothic arch (needle point) tracing and

condylar inclination. J Prosthet Dent. 1987 Nov;58(5):638-42.

2. El-Gheriani AS, Winstanley RB.The value of the Gothic arch tracing in the

positioning of denture teeth. J Oral Rehabil. 1988 Jul;15(4):367-71.

3. El-Gheriani AS, Davies AL, Winstanley RB.The gothic arch tracing and the

upper canine teeth as guides in the positioning of upper posterior teeth. J Oral

Rehabil. 1989 Sep;16(5):481-90.

4. Honorato Villa: Gothic arch tracing:JPD; 1959:9:624-628

5. Howard F. Smith: A comparison of empirical centric relation records with

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6. Keshvad A, Winstanley RB. :Comparison of the replicability of routinely used

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7. Max A Pleasure: occlusion of cuspless teeth for balance and comfort JPD:

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8. Obrez A, Stohler CS.Jaw muscle pain and its effect on gothic arch tracings. J

Prosthet Dent. 1996 Apr;75(4):393-8.

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