Jaw relation in rpd
-
Upload
vinay-kadavakolanu -
Category
Health & Medicine
-
view
547 -
download
34
Transcript of Jaw relation in rpd
Vinay Pavan Kumar K
2nd year P G student
Dept of Prosthodontics
AECS Maaruti College of Dental Sciences
Purpose of Recording the Jaw
Relations To establish and maintain a harmonious
relationship
To ensure that all the effects of occlusal loading be distributed
To best control the undesirable effects of rotational or torquing forces on the prosthesis.
To prevent any deflective contacts of the teeth during centric or eccentric closures
Recording Jaw relation
Before construction of framework - mounted on
an articulator
Definitive jaw relation – after functional
impression and altered cast
Methods of recording Jaw
relation
Direct apposition of cast.
This should not influence the path of closure of
mandible
Interocclusal records with posterior teeth
remaining
Occlusal relations using occlusion rims on
record base
one or more distal extension areas are present
a tooth supported edentulous space is large
when opposing teeth do not meet
Jaw relations records made entirely on
occlusion rims
when either arch has only anterior teeth present
opposing posterior teeth do not meet
Establishing Occlusion by the Recording of OcclusalPathways
Support the wax occlusion rim with a denture base
occlusion rim must be worn for 24 hours or longer
After 24 hours, the occlusal surface of the wax rim should show a
continuous gloss, which indicates functional contact with the
opposing teeth in all extremes of movement.
After a second 24- to 48-hour period of wear, the registration
should be complete and acceptable
Vertical Dimension
VDO
VDR
Freeway space
Altering the existing vertical
dimension of occlusion
Symptoms of diminished VDO like tired aching muscles
unexplained pain in the head and neck
region
shortened nose-chin distance
(appearance of premature aging)
Excessive Free way Space or ‘over-
closure’ of the jaws
Wearing of the teeth does not mean that
VDO should be increased – unless the free-
way space is greater than 4mm.
How to alter the existing VDO
1. Confirm the loss of VD by taking history, cephalometricexamination, and the presence of excessive free-way space.
2. Increase the existing VDO temporarily by fabricating an acrylic resin occlusal overlay appliance in maximum intercuspation, ensuring that 4mm of freeway space must exist.
3. Restore the desired VDO permanently with
the help of fixed or removable prosthesis only
after the physiologic response of the patient to
this appliance is positive.
Facebow transfer
To relate the maxillary cast to the
condylar elements of the articulator at
the same orientation that the maxillary
teeth have to the mandibular condyles of
the patient.
Horizontal jaw relation
centric relation centric occlusion
centric relation or centric
occlusion ?
The most delicate proprioception in your body is between the upper and lower teeth.
In more than 90% of people, C.O is 0.5 - 2mm in
front of the CR
Centric relationCentric occlusion
C.O should be recorded when there are cusps on remaining natural teeth that can guide the mandible back to its position.
C.R should be recorded for distal extension RPD, or when the opposing arch is edentulous.
When Not to Use Centric
Relation
Stable occlusion
Posterior centric stops present
No valid reason to change
Use maximum intercuspation
Try In Appointment
if the RPD opposes a complete denture
all posterior teeth in both arches are being replaced
if no opposing natural teeth are in contact
Provides verification of the jaw relation recorded
provides an, opportunity to view and approve the esthetic
size, color, and arrangement of the anterior teeth
Phonetic inspection
Desirable occlusal contact relationship
for removable partial dentures
Simultaneous bilateral contact – centric occlusion
Tooth supported partial denture – occlusion as in
natural dentition
Maxillary complete denture opposes partial denture
- bilateral balanced occlusion in eccentric positions
Bilateral upper distal extension base -
simultaneous working and balancing side contact
Only working contacts need to be formulated for
the maxillary or mandibular unilateral distal
extension removable partial denture
Bilateral distal extension mandibular RPD opposed
by natural dentition in the maxillary arch - Working
contacts are achieved
Artificial posterior teeth should not be arranged on
the sharp upward incline of the mandibular residual
ridge or over the retro molar pad
Possible scenarios adapted from Henderson place
emphasis on RPD stability
Three possible sequelae of occlusal error
If the premature contact is on a natural tooth, damage to
the tooth or its periodontal ligament may occur.
If the saddle bears the brunt of the force of closure, there
will be localised mucosal inflammation and resorption of
the underlying bone.
If the patient attempts to steer the mandible around the
premature contact until a more comfortable occlusal
position is found, this abnormal closing pattern throws
increased demands on certain muscles of mastication,
which may result in the patient complaining of facial pain.
Maxillary complete denture
opposing a RPD
Occlusal consideration in implant
retained partial denture
axial displacement of teeth in the socket are 25-100 μm,
while that of the osseointegrated dental implants has
been reported approximately 3-5 μm
natural tooth moves 56-108 μm and rotates at the apical
third of the root upon a lateral load
Dental implant moves 10-50 μm under a similar lateral
load
Conclusion
An ‘ideal occlusion’ in removable
prosthodontics is one which reduced de-
stabilisating forces to a level that is
within the denture’s retentive capacity
References Carr AB, Brown DT, McCracken’s Removable
Partial Prosthodontics, 12th edition, Canada,
Elsevier Publishers, 2011, pp:242-252
Stewart, Rudd, Kuebkar, Clinical Removable Partial
Prosthodontics, 2nd edition, India, All India
Publishers and Distributors, 2001, pp:367- 396
Jones DJ,Gracia LT, Removable Partial Dentures :
A Clinician’s guide, 1st edition, Singapore, Wiley-
Blackwell, 2009, pp : 90-94
Jacobs, R. and Van Steenberghe D. (2006),
From osseoperception to implant-mediated
sensory-motor interactions and related clinical
implications. Journal of Oral Rehabilitation,
33: 282–292.
Davies S.J, Gray .R and McCord J.F, Good
occlusal practice in removable prosthodontics
British Dental Journal 2001; 191: 491–502
Davenport .J.C etal The removable partial
denture equation, British Dental Journal 2000;
189: 414–424