PPT

3. INTER OCCLUSAL RECORDS
(bite registration)

4. Bite registration:
Is a technique done to transform the relation
between the upper &lower dental arch from
the patient mouth to the articulator.

5. Proper interocclusal record is important to
orient the die or dies of the prepared
&unprepared teeth in the same arch to the
opposing arch.

6. Bite registration allow the dentist to
observe accurately tooth contact, occlusal
discrepancies and to fabricate restorative
procedure for the patient without in
changing occlusion

7. Types of interocclusal records
Basically, there are two main categories of
interocclusal registration:
1- Centric interocclusal records
*Centric Relation
*Centric Occlusion
2- Eccentric interocclusal records.
*Lateral excursive records
*Protrusive relation records

8. Centric relation is a bone to bone
relation; relation of maxilla to mandible
independent of tooth contact and where
muscles are in physiologically
unstrained position.

10. Centric occlusion: is teeth occlusion while the
mandible is closing in centric.
Maximum intercuspation is the most complete
interdigitation of maxillary and mandibular teeth
regardless of condyle centricity. It may or may not
coincide with centric relation.
Diagnostic casts are mounted with centric relation
record to view the full range of mandibular
movement, whereas working casts should be
mounted with a record made at vertical dimension of
occlusion using maximum intercuspation of
unprepared teeth.

12. Ideal requirements of bite registration
material.
1- limited resistance before setting to avoid displacing the
teeth or mandible during closure.
2- Minimal dimensional change.
3- it should be easy to manipulate.
4- No adverse effects on the tissues involved in the recording
procedures.
5- it should accurately record the incisal and occlusal surfaces
of teeth.
6- it should be verifiable.
7- over clinically reasonable time period, they must have
solidity to retain the shape and strength when dental casts are
articulated.

13. 
8- Dimensional stability on storage.

9- No chemical reaction or adherence with tooth
structure.

10- Enables rechecking of the record

11- Acceptability to the patient(Taste agreeable and
tolerable).

*Low cost

14. Indications for interocclusal records
1- If the patient has an adequate number of teeth and a
stable intercuspal position, no signs and symptoms of
trauma to the occlusion and goal of treatment is to
maintain pre-treatment intercuspation and occlusal
vertical dimension (OVD).
*Most accurate method of articulation is to occlude opposing
casts by hand, without intervening bite registration material .
Recording material placed between teeth in this case often
prevents casts from maximal intercuspation and an interocclusal
record is registered at an increased OVD.
*Mounting casts in the maximum intercuspal position (MIP)
facilitates treatment.

16. 2- If the planned restorations involve terminal teeth in the arch.
• An interocclusal record is needed as there is insufficient
horizontal stability of the casts for hand articulation and
mounting.
• For opposing casts to occlude accurately, a tripod of vertical
support and horizontal stability must exist between the casts.
• To ensure that there are sufficient numbers of occluding g
teeth to mount working and opposing casts in MIP.
3- When terminal teeth are prepared for crowns or fixed partial
dentures and the third leg of the tripod is lost.
• *the dentist must fabricate an interocclusal record to
recapture the lost leg and create a tripod of vertical support
to mount casts accurately.

18. Materials for bite registrations
1- Bite registration Waxes.
2- Impression Plasters.
3-alginate impression material index.
4- Modeling Compound
5- Acrylic Resin.
6- Zinc oxide and eugenol Bite registration.
7- Elastomeric Materials.
8- Combination of some materials:
9-Recent Advanced Bite Registration.

19. Techniques of bite registrations

20. 1- Bite registration wax
It is the most versatile ,the reason is its easy manipulation and
when softened uniformly and remains soft for an adequate
working time.
Simple to Use, Cheap, Economic.
Disadvantages:
Low flow ( Not produce anatomical form)
Dimensional instability as room temperature changes & stress relaxation.
Spread out laterally without recording the occluso-gingival tooth anatomy.
May guide the patient to close in abnormal position if the wax not soft
enough.

21. Bite registration wax ,therefore , it has been
classified as most inaccurate material among the
interocclusal records studied?
• It is dimensionally in accurate.
• It has a high coefficient of thermal expansion.
• High resistant to closure.
• Distortion of wax during removal is also very
common, due to release of internal stresses.
• Lead to inaccuracies while registration is made

22. Waxes Techniques
1- Wax Squash Bite or laminated bite wafer
Used 2-3 layers of modeling base plate wax sandwiching a very
thin sheet of metallic foil or gauze for strengthening the wax.
This technique could be used in unilateral cast restorations or
when the occlusion is not stable.

24. 2-Wax bite rite or bite wafer;
several layers of wax about 1cm thick are softened
and shaped into a horse shoe soft roll, placed over
occlusal surface of mandibular teeth and the
patient is asked to close in centric then removed
after hardening.
It has the following disadvantages:
-Wax may distort on removal,
-Inaccurate, inconsistent and unstable record,
-Dimensional instability due to internal stress release,
-High fluidity of the material And on cooling from oral
cavity temperature it undergoes dimensional changes.

26. 3- Wax bite block;
*an occlusal rim of wax on a base plate is used
to record relation in case of restoring anterior
teeth in the absence of posterior teeth.

28. Impression plaster is basically plaster of Paris with modifiers.
Modifiers accelerate setting time and decrease setting
expansion.
Records of impression plaster are:
accurate.
Rigid after setting, and do not distort with extended storage.
Disadvantages:
1- it is difficult to handle because the material is fluid and unmanageable
prior to setting
2- final interocclusal record is brittle.
3- If hardens in patient′ s mouth in an undercut area, it will break if entered
undercuts.
Not used now.
2-Plaster impression

30. 4-Modeling compound
Becomes rigid upon setting , has been used to
fabricate segmental interocclusal records.
Disadvantages
• Flow of the material over natural teeth and over
soft tissues, which invites errors in repositioning
working casts within the bite registration.
• Abrasion of working cast dies during mounting
and subsequent removal of the record.

31. A properly mixed zinc oxide and eugenol can be
carried on both side a of a ready made jone’s bite
frame or a custom made carrier made of the neck of a
wire coat hanger after being contoured and trimmed
then introduced into the oral cavity and the patient is
instructed to close in centric occluding position.
It is one of the most acceptable methods for
recording centric occlusion.
A wire frame with fiberglass mesh carries the
zinc-oxide paste.
It can be used unilaterally or bilaterally .
5- zinc oxide and eugenol

32. Seat the frame with paste
in the patient mouth, being
sure that the wire frame is
NOT interfering with
occlusion.

33. bite frame

34. It has the following advantages;
1-Cusp tips and occlusal edges are reproduced to allow
accurate positioning of models.
2-The material adheres to the tray and has enough fluidity
before setting that helps to register details without any
interference to mandibular closure.
3-The material is rigid and stable after setting that allows
checking record accuracy.
4- Accurate record
5-Dimensionally stable , if stored according to manufacturer
instructions.
6-Could be reassembled if broken.
7-Could be used for production of the opposing model.
8-Rigidity & resistance to compression permitting easy &
controlled removal after setting, also helps in accurate seating
of the models.

35. Disadvantages:
1-Non elastic → distorts when removed from undercuts.
2-Thus teeth contour, axial walls, & embrasures are NOT
accurately reproduced with this record.
3- Long setting time.
Uses:
-To orient upper and lower models.
Recording opposing occlusion.

36. Ask the patient to close in centric position & observe the
correct position of the key point.
The frame is hold in place by the patient biting on it till
hardening of the material, then remove the frame, cut
interdental excess material using sharp blade & trim the
paste from areas expected to prevent the bite from seating
properly on the casts.
The wire arms should cover at least 2mm of the incisal edges of the
anterior teeth & occlusal surface of the posterior teeth, the paste is mixed
and spread on the maxillary teeth for about 2mm depth.
A key point is selected for centric occlusion and the patient is asked to
open and close several times in centric relation for training.

37. Auto polymerizing resin, is used to fabricate single stop
record by placing the material on posterior prepared
abutment to record interarch relation or used as vertical
to maintain vertical dimension.
6- Acrylic Resin
disadvantages
1-Dimensional instability ------due to
polymerization shrinkage
2- If hardens in patient′ s mouth in an
undercut area, it will never be removed
easily. It should be removed while still
soft, and this may lead to distortion
3- The strength and rigidity of the
material can damage plaster cast and die
during articulator mounting

38. Elastomers: using addition or polyethers. By syringing the
material on the occlusal surface of the mandibular teeth after
drying them and guiding the teeth to close in maximum
intercuspation.
These materials have the following properties;
-Accurate,
-Short working and setting time,
-High stiffness that show low strain on compression,
-Low flow that make the material offers little
resistance to intercuspation,
-Dimensional accuracy even after 7 days, do not
require carrier,
-Hand mixed or automixed.
But they are expensive.
7- Elastomers for IOR

39. Elastomers used for inter-occlusal record are condensation
silicone, addition silicone and polyether.
Addition silicone has gained acceptance-------more stable than
condensation silicone.
The silicone is divided into two parts and placed on the
right and left sides on the occlusal surface of the molars.
After setting ,the impression is removed and put into a bag
in absence of humidity.
Its advantages relay in dimensional stability and fine
details.

40. Disadvantages:
* Any compressive force extends on these materials
during mounting procedures may cause inaccuracies,
during mounting of the casts(spring action)
The spring action found in these materials causes the
articulated cast to open in centric relation position. Thus
the record should be trimmed and carefully seated over
the occlusal surface to minimize the negative spring
action.
*Cost compared to others

45. 7- Combination of materials
1- Wax + Elastomers
Bite registration materials could be used in
combination to get full use of the advantage of each
material.

46. 2- Wax + Zinc Oxide & eugenol
When inter-occlusal space for clearance between teeth
preparations is greater than 6mm ------used wax + zinc oxide
eugenol paste used.
The paste of zinc oxide and eugenol is added in the region of
first molars, in upper and lower wax sheet, after setting of it , it
is removed and kept in moist environment.

47. 3- Wax + Duralay acrylic resin
Two small perforations were made in the wax sheet
for the addition of small portions of resin. During the
plastic phase of the resin, the registration was
repositioned in the mouth until full polymerization.
After acrylic resin polymerization, the registrations
were removed and kept in a container with water.

48. 8-Recent Bite Registration
Articulation paper, waxes, pressure
indicator paste, etc. were all dentists had to
assess and balance the occlusal forces. Most of
these methods are not sensitive enough to
detect simultaneous contact, and none measure
both biting time and force.
Tekscan met the challenge by developing the
T-scan system.

49. It consists of: an ultra-thin, reusable sensor
which shaped to fit the dental arch. This sensor
is inserted into the sensor handle, which connects
into the USB port of computer.
T-Scan II
A computerized dental occlusal analysis system.

50. When the patient bite down on the
sensor, occlusal forces and occlusal
timing (from first contact to last) can be
monitored on the computer screen.

51. Advantage of T-scan II
-It can view, on screen, a patient sliding from CR
position into a lateral excursion.
- It locates occlusal interferences and determines
the relative force on each interference.
- The data of the recorded T-Scan dental occlusion
movie can be stored and retrieved it as needed.
- It helps to find the most traumatic occlusion
which is important implantation in order to reduce
the risk of implant failure

52. BioEMG
It is a device specifically designed to
accurately measure the rest and function
performance of the muscles

53. - The two programs; T-Scan together with
BioEMG evaluate the continuous
relationship between occlusion and
muscle function.
Unbalanced occlusion results in unbalanced
muscle function

54. Scannable bite registration materials
* Futar Scan
* Stone bite scan from drive.
* Metal-bite from R-Dental.
* Kanibite scan from kaniedenta.
• Virtual CAD bite from ivoclar. No contrast
medium required.
All of these materials are vinyl polysiloxanes.
all saves considerable time and eliminates a possible
source of error.

55. Futar Scan is a scannable, addition-curing,
polyvinyl siloxane bite registration material that
has been optimized for use with any CAD/CAM
system. It can be scanned by optical or laser
systems without the powder needed with some
systems. Futar Scan stands out from other bite
registration materials with its excellent optical
properties, guaranteeing high recording quality
and optimal image replication.

56. EXACTA Dental Direct has recently added
StoneBite Scan to its computer-aided
design/computer-aided manufacturing (CAD/CAM)
product line. StoneBite Scan is a vinyl polysiloxane
bite-registration material that was designed for
CAD/CAM users who need to scan registrations
during the design phases of CAD/CAM restoration.
StoneBite can easily be trimmed, and its reflective
properties provide crisp and accurate optical
impressions. The medium viscosity of the material
will not slump or flows off the teeth. Each kit
contains two-50ml cartridges and 12 ribbon-style
mixing tips.

57. Ivoclar Vivadent introduced Virtual CAD bite—
an addition-reaction silicone fast, strong, and
scannable bite-registration material. This optimized
bite-registration material is perfect for CAD/CAM
processes and is available with low-volume mixing
tips for greater efficiency and decreased material
waste.
It is also excellent for conventional bite-registration
techniques. Peppermint scented, Virtual CAD bite
material sets in just 45 seconds, substantially
reducing the risk of distortions or inaccuracies from
patient jaw movement.

58. Advantages:
Fast
 Strong
Non- slump consistency ( not flow into
interdental space)
More pleasant for patients .

61. Bite registration for CAD/CAM procedures:
There are digital impression taking procedures. Which are
employed in conjunction with the computer-aided design/
computer –aided manufacturing (CAD/CAM) of tooth
restorations. Digital impressions are taken either:
- Of the model in the dental lap.
- Directly in the mouth at chairside using an intraoral
scanning device or camera
- In order to determine the occlusal relationship, an
antagonistic bite registration is required. Being able to
directly capture images of this bite record with a scanning
device or camera without having to apply a contrast
medium.

62. 3 D laser scan
Digital Bite Registration using CAD/CAM
machine

63. Methods used for the evaluation of occlusal
relationships:
1- quantitative method
2- qualitative method
Accuracy of an interocclusal record influenced
by:
1- Material properties.
2- Recording technique.
3-Reliability of mandibular position,
4-Muscular action.
5- Tissue changes within the joint.