Occlusion in prosthodontics- Denture Placement and Occlusion Correction

3. Dr. Amal Fathy Kaddah
Professor of Prosthodontic,
Faculty of Dentistry,
Cairo University

5.  Clinical errors
 Technical errors
 Inherent deficiencies in the
material itself
Introduction
Causes of Denture Errors

6.  Errors in impressions
 Ill-fitting trial denture bases
 Inaccurate jaw relation records
 Errors during transfer of the records
to articulator
 Incorrect arrangement of posterior
teeth
Clinical Errors

7. Processing and Technical faults
Distortion due to improper flasking
 Failure to close flask completely
 Too much pressure while closing the flask
from the flask press.
 Tooth movement during flasking or packing
 Failure to cool flask before deflasking
Warpage due to overheating during polishing

8. Technical discrepancies could be
due to:
1- Dimensional Changes in the wax due to
variation in temperature.
2- Expansion of the investing material during the
processing (plaster and dental stone ).
3- Errors which may occur during packing of
acrylic resin.
4- Changes in the acrylic resin material during
processing procedures (polymerization
shrinkage).

9. Types of Occlusal Errors
 C.O. not coincide with C.R.
 Premature contact (high point) in
one or both sides
 Uneven distribution of occlusal
contacts
 Eccentric movement prematurities
(protrusive & lateral)

10. Why is it difficult to detect
occlusal errors in the mouth?
*Shifting of denture bases,
incorrect closure by patient
* Resiliency of the Soft tissue
* Negative attitude (assume an
error exists and try to find it)

11. How can you Detect Occlusal
Errors?
 Denture dislodges (instability) or
shifts when patient occludes
 Patient complains of pain beneath
denture bases >> worst by time
 Sliding of denture bases or uneven
pressure caused by faulty occlusion
can lead to ulceration of mucosa.

13. Steps of
Occlusal
Correction

14. TRIAL INSERTION STAGE

15. Cervical necks tilt posteriorly from the central incisor to the canine

16. • The appropriate Curve of Spee should
be incorporated into the setup.
• Make sure the posterior mandibular
teeth are centered over the ridge

17. • The plane of occlusion should be parallel to the
body of the mandible and extends from the
incisal edges of the central incisors and the
middle portion of the retromolar pads
bilaterally.

18. TRIAL INSERTION STAGE

19. TRIAL INSERTION STAGE

20. • Finalize Wax up

21. Fabrication of Occlusal index for
clinical remounting
• At the end of the try in stage where
the dentist and patient are both
satisfied.
• This is a time save procedure for you
because you do not have to make a
new facebow record at the time of
delivery.

22. Place the Facebow remount jig on the lower member of the
articulator. Verify that the incisal guide pin is set at zero.
Allow plaster index to completely set. Verify that the
maxillary teeth can be repositioned into the indentations.
Occlusal index for
clinical remounting

23. To save the position of
the maxillary cast
No need for face bow
record in the clinical
remounting step

24. Flasking for Processing

25. - During deflasking: be careful to preserve the
cast, also do not left or remove the denture
from the casts
 Clean the denture and cast from plaster.
 Remove any stone or bubbles from the
exposed acrylic resin and from the occlusal
surfaces of the teeth.
 Remove any particles of stone from the base
of the cast and index grooves.
 Using a stiff brush, soap and water clean the
denture and cast before starting the
laboratory remount

26. Dentures being re-mounted on the original
articulator and adjustments carried out to provide
correct articulation (Laboratory Remounting).

28. * Laboratory Remounting
Carried out, after defalsking and before
polishing of the denture, (before the
dentures are delivered to the patient),
for perfection of occlusion.
Occlusal discrepancies may result
from technical discrepancies.

29. Purpose
• To correct errors in occlusion that
have occurred during processing
• To return dentures to the correct
vertical dimension
• To obtain a smooth even contact
of the teeth in centric and
eccentric positions.

30. Disadvantages
 Cannot correct errors made while
recording jaw relations
 Cannot correct errors made while
mounting the casts on the articulator
 Does not compensate changes caused
by settling of the denture bases

31. The processed denture on the master cast is
repositioned to its old position on the articulator
by means of remounting indices made in the
master cast before mounting.

32. Remount and Adjust for Processing Errors

33.  The condylar elements of the articulator are
locked in the centric relation and the
articulator is closed.
 The incisal guide pin not contact the incisal
guide table, The occlusal vertical dimension
has been changed and must be re-established.

34. • Place red articulating paper between
the teeth and gently tap the teeth
together in centric occlusion.

35. The adjustment in centric occlusal position
should be stopped when widespread
Contacts are produced

36. The incisal guide pin usually stays in
contact with the incisal guide table.

37. The adjustment in eccentric occlusal
positions

38. The adjustment in eccentric occlusal positions should be stopped
when widespread Contacts are produced and the incisal guide pin
usually stays in contact with the incisal guide table.

40. The Aim of Laboratory
Remounting
The prematurities are ground until
multiple, uniformly distributed and
even contacts are obtained bilaterally
The incisal guide pin stays in contact
the incisal guide table

41. Finishing and Polishing

43. a . Adjustment of Processing Error .
b . Finishing and Polishing of Denture.
1. PRE-INSERTION PREPARATION
2. INSERTION VISIT
1 . Re-examine dentures and foundation tissues.
2 . Insert each denture independently.
3 . Occlusal equilibration to be accomplished
at this time.
a . Clinical Remount of the upper cast.
b . Interocclusal records - waxes.
c . Remount the lower denture.

47. Correcting occlusal
errors in patient's mouth
Articulating paper in the mouth
. Not give accurate indication due to the
resiliency of the supporting tissues
Adhesive Wax

49. or

52. Clinical remount
Dentures should be remounted
with new records obtained from
the patients
Mount the upper cast according to a
face-bow record or occlusal index *
and Mount the lower cast according
to a new centric relation record.

53. Advantages of Clinical Remounting
with New Interocclusal Records *
 Less chair side time
 Corrections away from the patient’s
view
 No saliva which makes detection by
articulating paper difficult
 No shifting of dentures or incorrect
closure by patient

54. The Aim of Clinical
Remounting
The prematurities are ground
until multiple, uniformly
distributed and even contacts
are obtained bilaterally

55. Clinical remounting is
currently the most
commonly preferred
method of occlusal
correction

56. Fabrication of Remount casts
at the time of delivery
Block out undercut areas
in the tissue surfaces
before pouring the plaster

57. Clinical Remounting Procedure
 Ask patient to bite on
cotton rolls for 10 min.
 Guide mandible into CR
several times.
 Bite registration
material is placed on
the posterior teeth of
the mandibular denture

58. Clinical Remounting
Procedure
 Guide mandible into CR
 Obtain the new
interocclusal record of
C.R. using your recording
medium of choice,
making sure that the
teeth do not touch. ???

59. Try in??????

60. Do I need New Face
bow
RECORD?????????
Remount upper
denture using
remounting jig
Clinical Remounting Procedure

61. Mounting the lower cast with new CJRR
Make sure that the denture bases are not contacting
posteriorly.

63. I. Selective grinding
II. Milling
The procedures of
Perfection of occlusion

64. Selective Spot Grinding
* Reducing premature contacting
surfaces, so that an equal pressure
exists at all points with no interference

65. The buccal cusps of the mandibular
posterior teeth and lingual cusps of
maxillary teeth are called supporting cusps.
These cusps occlude in central fossa and
maintain the occlusal vertical height.
They also called centric cusps and holding
cusps.
Supporting cusp or Functional Cusp
The lingual cusps of mandibular posterior teeth and buccal
cusps of the maxillary posterior teeth called guiding cusps.
They guide the mandible in lateral movements.
Non Functional Cusps

66. Note that the stamp
cusps (those fitting
into the central
portion of the
opposing teeth)
compromise 60% of
the total faciolingual
tooth dimension.

67. Basic Tooth Positions
Balancing Contacts Centric Occlusion Working Contacts
Ideally all holding cusps * of the maxillary and mandibular
posterior teeth will make simultaneous contacts.

68. How to Recognize Premature
Contacts?
A dark ring
with a light
center usually
denotes a
premature
contact

69.  You should distinguish between marks
made by normal occlusal contacts and
those of premature contacts
How to Recognize Premature
Contacts?
 Articulating paper
should not be reused
many times and
should be changed
often.

70. Selective Spot Grinding
Make grinding until even (same
intensity), stable, and multiple
marks spread over wide area in both
sides

71. *Eliminating Occlusal Errors
(selective grinding)
Procedures of

72. The sequence of steps should
be as follows
 Restore the vertical dimension
 Re-establishment of C.O.
 Correction of working side occlusal
errors.
 Correction of balancing side errors.
 Correction of protrusive relation.

73. • The condylar elements of the articulator
are locked in the centric relation and the
articulator is closed.
• Grind the teeth with small diamond stones.
• Use red articulating paper to mark the area
of premature contacts for making centric
occlusion and blue articulating paper for
the eccentric movements
1. Adjust the articulator to the proper setting

74. • Lock the upper arm of the articulator in
centric relation. Check the occlusion by
opening and closing the articulator.
• Place red articulating
paper between the
teeth and gently tap
the teeth together in
centric occlusion.

75. 2. Establish the occlusal vertical
dimension in centric:
Occlusal VD is maintained
by occlusion of palatal
upper cusp and buccal
lower cusp
(in normal occlusion)
( Supporting cusps)

76. a. If the cusp is high in centric and
eccentric relation, reduce cusp.
b. If the cusp is high in centric but not
eccentric, deepen fossa.

77. Correction of occlusion
done by reducing
buccal incline of upper
Lingual cusp and
Lingual incline of lower
buccal cusp or
deepening their
corresponding fossae
p
B

78. •Do not grind the cusp
tips unless it is high
in every excursion,
but rather reduce the
fossa or inclined
plane of the cusp.
3- Re-establishment of C.O.

79. Problem: Teeth too nearly tip to
tip (If insufficient
overjet)
Solution: Grind Inclines
- Grind the inner inclines of upper buccal & lower lingual
Cusps.
- Grind lingual incline of upper lingual cusps.
- Grind buccal incline of lower buccal cusps.
So that the cusp tips contact the central fossae.
The cusp tips should not be shortened.
Re-establishment of CO

80. Problem: Too much horizontal overlap(upper
teeth too far buccaly to lower ones)
Solution: . Broaden central fossae
• Grind the inner inclines of upper
lingual cusps & lower Buccal cusps.
Re-establishment of CO
The cusp tips should not be shortened.

81. The adjustment in centric occlusal position
should be stopped when widespread
Contacts are produced

82. Reduce the teeth until the incisal pin
touches the incisal guide table and uniform
contact exists on all posterior teeth.
Anterior teeth should not touch in
centric occlusion.

83. After the CO re-establishment
 DO NOT Reduce maxillary lingual
cusps.
 DO NOT Reduce mandibular buccal
cusps.
These cusps are essential to maintain
the recorded vertical dimension
 DO NOT Deepen the fossae.

84. Loosen the locks on the condylar elements
and move the denture in eccentric
movements. Using blue articulating paper
between the teeth.
4. Refine occlusion in eccentric

85. The adjustment in eccentric
occlusal positions

86. The adjustment in eccentric occlusal
positions should be stopped when widespread
Contacts are produced and the incisal guide
pin usually stays in contact with the incisal
guide table.

87. • If the cusp contacts
prematurely on closure
as before, but is not
premature in lateral
excursions, the fossa is
deepened
• Prematurely contacts in
centric and in lateral
excursions, the cusp is
reduced in height.

88. a- Lateral movement:
i. On the working side:
Follow "Bull rule" of reducing buccal
upper and lingual lower cusp inclines.
b. Protrusive movement:
Bull rule does not work. Reduce
interceptive cusp as shown by the carbon
paper.
ii. On the balancing side:
Reduce distal inclines of maxillary cusp
and mesial inclines of mandibular cusps

89. • Reduce lingual inclines of
buccal cusps of upper teeth.
• Reduce buccal inclines of
lingual cusps of lower teeth.
ON WORKING SIDE ONLY!!!
i- "Bull rule on the working side "

90. Problem:
Buccal and
lingual cusps
too long.
"Bull rule on the working side "

91. Occurs between the lingual upper
and buccal lower supporting cusps
Which are the functional cusps
Adjustment Rule:
Buccl inclines of the lingual upper cusps .
lingual inclines of the buccal lower cusps .
LUBL
ii. Correction of Balancing Side interferences

92. ii. Correction of Balancing Side Errors
Decide which supporting cusp
maintains CO and reduce its opponent.

93. If interference exists on the balancing side Grind
the lingual incline of the mandibular buccal cusp.
It is a centric holding cusp so grind carefully
and do not reduce the cusp tip.
Correction of Balancing Side interferences

95. a. If the anterior teeth have heavy contact
with no contact on the posterior teeth
grind the labial surface of the lower
anterior and the palatal surface of the
upper anteriors.
b. If heavy posterior contact exists with no
anterior contact reduce the distal
inclines of the maxillary cusps and the
mesial inclines of the mandibular cusps.
b- Correction of Protrusive Relation

96. In protrusive excursion, premature contacts are
eliminated by grinding the distal facing inclines of upper
teeth and mesial facing inclines of lower teeth
DUML
Adjustment Rule:

97. Proceed with selective
grinding until you get
balance at centric
contact and occlusal
harmony in eccentric
movements

98. Briefly
BULL rule in:
-Working side interferences.
LUBL rule in:
-Non-working side interferences.
DUML rule in:
-Protrusive interferences.

99. Direct Intraoral Correction
 Requires a lot of patient cooperation
 Patient should have good
neuromuscular control
 Saliva
 Inaccurate closure by patient
 Misleading due to resiliency of
tissues and shifting of denture bases
Disadvantages

100. Direct Intraoral Correction
• Check for the coincides of maximum
intercuspation with centric relation
position, and whether the vertical
dimension of occlusion is unchanged or not.
• Only small discrepancies in maximum
intercuspation, can be adjusted following
the same rules as for correcting occlusal
errors on the articulator.

101. Rules for selective grinding:
1. Never grind a centric cusp tip unless it contacts prematurely
in all excursions of the mandible. Always grind the opposing
fossa or marginal ridges where the centric holding cusps occlude
2. Utilize the BULL rule when perfecting working occlusion, For
interference in the posterior teeth reduce the upper buccal
cusp slopes and the lower lingual cusp slopes.
3. When grinding to perfect balancing occlusion never grind the
interfering cusp tips but grind the cusp inclines.
4. In correcting protrusive interference in the anterior teeth
grind on the labial portion of the incisal edges of the lower
teeth and the lingual portion (palatal surfaces) of the upper
teeth.
5. In protrusive balance, the anterior teeth should make incisal
edge contact at the same time that the tips of the buccal and
lingual cusps of the posterior teeth contact.

102. Balance occlusion in
Working side, Balancing
side, Protrusive position

103. II- Digital methods
Digital technology helps
clinicians to identify premature
contacts, high forces, Timing
and interrelationship of
occlusal surfaces.

104. T-Scan is an objective assessment
tool used to evaluate the occlusion of
a patient. Unlike articulating paper,
which can only determine location,
T-Scan can identify
both force and timing, two of the most
fundamental parameters for measuring
occlusion.

105. II. Milling XXX
A small amount of carborubdum
abrasive paste is placed over the
lower teeth and the articulator is
closed in centric position. Several
movements are made from centric
into each eccentric position to
eliminate any slight interference

106. Remounting has the
following advantages
1- Reduce patient's participation.
2- Allow for better visualization.
3- Provides a stable working foundation.
4- More accurate markings with the
articulating paper in absence of
saliva.

107. 3. POSTINSERTION CARE
1 . First appointment within 48 hours of delivery .
2 . Second appointment within 3 days .
3 . Third appointment within 1 week of 2nd visit .
4. CASE COMPLETION
1 . Patient able to masticate food .
2 . Patient should present a normal individual appearance .
3 . Patient should be able to speak distinctly .
4 . Patient should experience oral comfort .
5 . Patient should be educated as to the need for periodic
examination .
5. RECALL

108. References
1. Boucher's prosthodontics treatment for edentulous
patients. Twelfth Edition. Chapter 20.
2. Complete Denture Prosthodontics, 1st Edition, 2006 by
John Joy Manappallil, chapter 19
3. Dalhousie continual education
4. Denture placement & patient education - dr.Rola shadid
https://drrolashadid.Weebly.Com/uploads/1/4/9/4/14946992
/lecture_10_1.Ppt
5. Https://wsdav6.Squarespace.Com/s/i-hate_love-complete-
dentures-ronnie-schnell.Pdf
6. John Beumer III, DDS, MS: 24. Refine Denture Setup
Division of Advanced Prosthodontics, Biomaterials and
Hospital Dentistry UCLA School of Dentistry
7. Washington state dental association's 2015 pacific ... -
WSDA