Horizontal Jaw relations in Complete denture prosthodontics. Presentation by Dr. Joel Koshy MDS

1. Horizontal Jaw
Relations
Created by: Dr Joel Koshy Joseph (MDS)

2. Jaw relations steps
 Orientation Jaw relation
 Vertical Jaw relations
Horizontal Jaw relations
This is the anteroposterior relation of the mandible
to the maxilla in the horizontal plane.

3. Horizontal Jaw relation
Centric Relation Eccentric Relation
Protrusive Lateral

4. Centric Relation
• 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 eminencies. This
position is independent of tooth contact. This position is
clinically discernible when the mandible is directed superiorly
and anteriorly. It is restricted to a purely rotary movement
about the transverse horizontal axis

6. • Occlusion, when the mandible is in Centric
Relation, is called Centric Occlusion

7. Maximum Intercuspation
• The complete intercuspation of the opposing teeth
independent of condylar position, sometimes referred
to as the best fit of the teeth regardless of the
condylar position, is also called maximal
intercuspation

8. Why is Centric Relation so important?
1. In natural dentition, MIP may not coincide with CR.
This doesn’t create any damage as the proprioceptive
receptors of PDL directs the mandible to safe contact.

9. • When there are no teeth, our brains don’t know
where to bite, hence we need to rely on Centric
Relation.

10. 2. Centric Relation and Transverse Horizontal Hinge axis
• Position of Centric Relation and Terminal hinge axis coincide.
• Hence, the mandibular cast will also be correctly oriented to the opening
axis of the articulator only if it is mounted in CR.

11. 3. Centric Relation and Vertical dimensions.
Centric Relation changes with Vertical dimensions. Hence, Centric relation must be
recorded at the established vertical dimension.

12. 4. Centric Relation is a learnable position that a patient can
voluntarily reproduce and verify over time.
5. It’s comfortable and convenient to the patient
6. This provides easy access to all other excursive positions.

13. Method to Record Centric Relation
• To record Centric relation, the mandible first has to
be retruded.
• The following are the Passive and Active methods to
make the patient retrude the mandible.
Passive Method:
1. Relax, pull the jaw back and close on back teeth.

14. 2. Get the feeling of pushing the upper jaw out and close on back teeth.
3. Touch the posterior part of the upper denture with tongue and close.

15. 4. Swallow and close.
5. Tap the occlusal rims together repeatedly and rapidly.
6. Tilt the head back while performing the above exercises
7. Protrude and retrude the mandible repeatedly holding his/her fingers lightly
against the chin.

16. Active Methods
1. The dentist places his thumb and forefinger on the patient’s chin to exert a
mild but firm posterior force while the patient closes on the rims. This will
prevent moving the jaw anteriorly.

17. Active Methods
2. Dawson’s bimanual palpation:
The dentist stands behind the patient and places all four fingers of both hands on
the lower border of the mandible on either side. The thumbs are placed over the
chin such that they contact the midline. The patient is instructed to open the
mouth and then close slowly. As the patient closes, the dentist applies an upward-
lifting force with the finders on the inferior border and simultaneously applied a
downward force with the thumbs.

18. Methods used to record CR
1. Static Method/ Pressureless method:
No functional or excursive movements are used. Also known as a tentative
centric record.
With Heat With Stapler Pins
Not recommended:
Chances of burning and injuring lips and cheeks.
No Equalization of pressure
Difficult to prevent movement of rims while seating.

19. Recommended
a. Nick and Notch Technique

20. Video on Jaw relation

21. b. Interocclusal check records:
This is used to verify the centric jaw relation at the time of try-in or denture
insertion.

22. 2. Functional Method / Chew In Methods/ Pressure Method:
Patient is asked to perform border movements like protrusive
and lateral movements to find the most retruded position of
the mandible.
Requirements:
1. Occlusal Rims fabricated with slightly increase vertical
height
2. Very stable record bases.
Advantage:
• More accurate than static methods.
• Vertical dimension and CR can be determined.
Disadvantage:
• Difficult to record incases of displaceable basal seat.
• Difficult to record if patients neuromuscular coordination is
poor.

23. i) Needle- House method:
Rims to be fabricated from impression
compound.
Four metal balls embedded in canine
and molar region (2 each quadrant).
Insert occlusal rims and ask patient to
perform functional and excursive
movements.
Balls make 3D diamond-shaped
tracing over the lower rims.

24. ii) Patternson Method:
Wax occlusal rims are fabricated.
Trench or trough is made in the
mandibular occlusal rim
This trench is filled with equal mixture of
carborundum paste and plaster.
Insert the rims, and ask the patient to do
functional movements.
This produces compensating curves in
the plaster lower rim. Rims are
articulated and is joined together with
metal staples.
iii) Meyer’s Method:
Soft wax is used to generate functional pathway and record CR.

25. 3. Graphic method:
Gothic Arch tracing:
• Hesse (1879)  Gysi (1910).
• Aka Arrow head tracing / Needle Point tracing
Pantographic tracing
Gothic arch tracing
Verify the centric

26. • Types:

36. Advantage :
• Most accurate method of recording CR.
• Allows equalization of pressure on the supporting tissue.
• Easily verifiable
• Recordings can be transferred to a semi-adjustable articulator
Disadvantage:
• Difficult to locate the centre of the arches
• Time-consuming
• Training the patient to make mandibular movements is v difficult.
Indications:
• Broad edentulous sides
• Adequate interarch space
• In patients with habitual centric ( graphic method breaks all neuromuscular reflex)
Contraindications:
• Severely resorbed ridges and flabby ridges
• Reduced interarch space
• TMJ arthropathy
• Abnormal Jaw relations ( Class II / III )

37. Video on Extra-Oral Tracers

38. Video on Intra-oral tracers

39. Pantographic tracings
Pantograph: Instrument used to graphically record in, one or more
planes, paths of mandibular movement and to provide information for the
programming of an articulator.

40. Pantographic tracing (Pantogram): A graphic record of mandibular
movement usually recorded in the horizontal, sagittal and frontal planes
as registered by styli on the recording tables of a pantograph or by means
of electronic sensors. (Digital Pantogram).

41. Advantage :
• Recordings can be transferred to a fully adjustable articulator.
• This can also be used to record eccentric relations.
• Very accurate.
Disadvantage:
• Difficult to locate the centre of the arches
• Time-consuming
• Training the patient to make mandibular movements is v difficult.
• Procedure is complex.

42. Eccentric relations
Definition: Any relationship of the mandible to maxilla other than
Centric relation.
Protrusive Relations Lateral Relations
Recording these relations is very important if a balanced occlusion is
planned.

43. Protrusive Relations Lateral Relations

44. Some semi adjustable articulators are not capable of
accepting Lateral records.
Hence, to find the Bennett angle:
L = (H/8)+ 12 formulae is used.
H= Condylar guidance
L = Bennett angle

45. Summary
Jaw Relation
Orientation Vertical Horizontal
Orientation of the maxillary
occusal rim to the cranium is
done using Facebow.
OR
Maxillary occlusal rim is
aligned with Camper’s line
(Ala tragus Line) posteriorly
and Interpupillary line
anteriorly.
Vertical dimension at Rest
1. Facial Measurement
1. Swallowing
2. Tactile sense
3. Phonetics
4. Facial expression
2. Measurement of anatomical landmarks
Vertical Dimensions at Occlusion
1. Physiologic methods
1. Niswonger’s method
2. Swallowing threshold
3. Silverman’s Closest speacking space
4. Neuromuscular perception
5. Aesthetics
2. Mechanical Methods
1. Ridge relations
1. Incisive papilla to mandibular
incisors
2. Ridge Parallelism
2. Pre extraction records
1. Profile photos
2. Profile silhouettes
3. Radiographs
4. Articulated Cast
5. Facial Measurements
3. Measurement of former dentures
Methods to retruding mandible
1. Passive Methods
2. Active Methods
1. Thumb on chin
2. Dawson’s bimanual
technique
Recording CR
1. Static:
1. Heat
2. Stapler
3. Nick and Notch
4. Interocclusal Records
2. Functional Method:
1. Needle House Method
2. Patterson method
3. Meyer’s method
3. Graphic Method
1. Gothic Arch tracing
2. Pantographic tracing