checking the occlusion - psau · checking the occlusion if the try- in has been done carefully, the...
TRANSCRIPT
Checking the Occlusion If the try- in has been done carefully, the occlusion should be almost
perfect. Slight unevenness often occurs, due to processing errors, so
the occlusion should be checked with articulating paper
Place a piece between the teeth and ask the patient to chew up and
down in centric occlusion.
Remove the dentures from the mouth and examined- them.
The occlusal surfaces will exhibit areas of blue coloration where the
cusps and fossae of the opposing teeth have been in contact.
These blue areas should be evenly spread over the occlusal surface,
and the coloration of them should be uniform.
Areas of hard or uneven pressure will show up as darker, and border,
blue spots;
Area of low pressure, or no contact at all, as very lightly coloured
spots, or not coloured at all.
To equalize the pressure the high spots should be lightly ground.
Checking centric occlusion
II- Correction of vertical dimension of occlusion.
If VDO is slightly high, it is corrected by selective grinding.
If VDO is excessively high or low:
A- If the occlusal plane of the upper is judged to be correct, a new lower denture is constructed.
B- If the occlusal plane is incorrect, new upper and lower dentures should be constructed
Occlusal Analysis
Place patient in centric relation
Visually check the occlusion
Stabilize mandibular denture
Check with articulating paper
III- Elimination of the Occlusal Errors
(occlusal disharmony) in Anatomic Teeth
Causes of Occlusal Errors
(occlusal disharmony)
Clinical errors (Errors in jaw relation, try inand non use of face bow).
Errors in mounting models.
Errors of processing.
Anterior Open Bites or
Unstable Posterior Contacts
Posterior denture base contacts
Occlusal prematurities
Use articulating FILM to mark and to eliminate gross interferences prior to remount
Finished Dentures Exhibiting Incorrect
Centric occlusion
If the difference is notmore than a 1/4 cuspit may be correctedby means ofselective grinding.
Grind the mesial occlusal planes of the upper teeth and the distal occlusal planes of the lower teeth until an even inter-digitizing occlusion is obtained in the retruded position.
When the error is gross it will require theremoval of all the posterior teeth fromthe lower denture
In most cases of gross error the dentureneed to be completely remade.
If the overjet resulting from the new relation is abnormal the lower front teeth must also be removed from the denture and re-set.
Denture with gross occlusal error
Jaw relation record
Denture mounted and lower
posteriors removed
Technique of replacing posterior teeth
Teeth waxed-up
Packing and curing of
resin
I- Intra-oral methods.
II- Direct remount (Laboratory remounting).
III- Remount via new jaw relationship (Clinical remounting).
Checking and correcting interferences in
centric occlusion by selective grinding.
Checking and correcting interferences in
Left lateral occlusion by selective grinding
Checking and correcting interferences in
right lateral occlusion by selective grinding
Checking and correcting interferences in
protrusive occlusion by selective grinding,
Basic Tooth Positions
Balancing Contacts Centric Occlusion Working Contacts
Balanced OcclusionEnsure:
Balancing contacts are present
Balancing contacts not heavier than working contacts
Light grazing contacts of the anterior teeth in excursions
Re-establishment of CO
Problem: Teeth too longSolution: Deepen the fossae
Re-establishment of CO
Problem: Teeth too nearly end to endSolution: Grind Inclines
Re-establishment of CO
Problem: Too much horizontal overlapSolution: Broaden central fossae
After the CO re-establishment….
DO NOT:
• Reduce maxillary lingual cusps.
• Reduce mandibular buccal cusps.
• Deepen the fossae.
Correction of working side occlusal
errors.
Reduce lingual inclines of buccal cusps of maxillary teeth.
Reduce buccal inclines of lingual cusps of mandibular teeth.
ON WORKING SIDE ONLY!!!
Correction of working side occlusal
errors.
Problem: Buccal and lingual cusps too long.Solution: Change inclines of balancing cusps.
Correction of working side
occlusal errors.
Problem: Buccal cusps are too longSolution: Change lingual incline of maxillary buccal cusp
Correction of working side occlusal
errors.
Problem: Lingual cusp too long.Solution: Change buccal incline of lingual cusp of mandibular tooth.
Correction of balancing-side errors.
Reduce lingual inclines of mandibular buccal cusps; or
Decide which supporting cusp maintains CO and reduce its opponent.
Correction of balancing-side errors.
Grind the lingual incline of the mandibular buccal cusp.
Correction of protrusive relation.
Distal inclines
Mesial inclines
Base indexed for remounting
The Split Cast Method (Laboratory
Remount)
Laboratory remounting
A- Recording centric relation without
tooth contact
Ask patient to bite on cotton rolls for 10 min.
Guide mandible into CR several times.
Wax is placed on the post. Teeth of the mandibular denture.
Place both dentures in the patient’s mandible
is guided in a hinge movement.
Obtain inter-occlusal record at centric relation without tooth contact.
B- Mounting of the upper denture using
face bow index
C- Mounting lower denture using centric
relation record.
Centric occlusal interference marked by
articulating paper
Detection and correction of occlusal
error on the articulator
Interference in centric
is marked
Interferences removed by selective
grinding
Interference in right lateral is marked by blue
articulating paper and removed by grinding
Interference in left lateral is marked by blue
articulating paper and removed by grinding
Occlusal contact during protrusion is
checked by red paper
Interference in protrusion (Red points)
removed by grinding
Carborundum paste on occlusal surface and
milling in
PHONETICS WITH NEW
DENTURES
1- Bilabial sounds
These sounds are produced by both lips e.g. B, P and M.
- Letter M is used for checking the vertical dimension of occlusion and
freeway space.There should be 2-4 mm between upper and lower teeth.
2- Labio-dental sounds
-- Incisal edges of maxillary incisors will contact the vermillion border of lower lip e.g. F V and PH.
-- Test sentence : Very fine coffee.
- Can be used to determine length and facio-lingual position of maxillary incisors.
Difficulty in pronouncing the
consonants F, V, PH.
If the occlusal plane is set either too high ortoo low.
If the anterior teeth are placed too far palatally.
3- Linguo-dental sounds
-The tip of the tongue contact the lingual surface of upper incisors
-e.g. TH.
-Test sentence: They thought they were three.
-Used to verify :
-A- Adequate freeway space.
-B- Position of maxillary anterior teeth.
4- S Sounds
-In these sounds, a slit-like channel is formed between the tongue and the palate through which air hisses e.g. S, C (soft) and Z.
-- Test words: Mississippi, yes and see.
-Used to help determine if there is adequate freeway space.
- There should be 1-2 mm separation between premolars during production of S sounds (Closest speaking space).
A- Lisping on pronouncing the consonants
S, C (soft) and Z.
If the channel is obliterated as in:
The anterior part of the upper denture,covering the hard palate is thick.
The anterior teeth are placed too farback.
B- Whistling on pronouncing the
S, C (soft) and Z sounds
If the channel is too narrow as in:
The dental arch too narrow.
Cramped tongue.
The anterior teeth are placed too faranteriorly.
C- Clicking of the teeth on pronouncing
the consonants S, C soft, Z, Ch, J
In excessive vertical dimensions
Test words:
Mississippi, yes, see, buzz and judge.
5- Linguo-palatal sounds
-Formed by the tongue and palate..
A- Linguo- alveolar
-The tongue contact the anterior portion of hard palate e.g. T and D.
-- faulty phonation of T, D and N. occurs when:
-A- The anterior teeth are placed too far lingually
-B- The arch too narrow, leads to cramped tongue.
-Test sentence: Tom did not do it.
B- Tongue and palate just
behind alveolar sounds
These letters are J, CH and SH.
Test sentence: Jack jumped with the children.
Faulty phonation of consonants
Ch, J, Sh
Results from thickening ofthe anterior part of thedenture base covering thehard palate.
C- Velar sounds
Tongue and soft palate sounds e.g. K, G and NG.
Test sentences:
King Kong.
The king sang a song.
Difficulty in pronouncing the sounds
G, NG, C hard and K
If the posterior border of theupper denture does notmerge into the soft tissues.
6- Nasal sounds
- Air comes through the nose e.g. M, N, and NG.
- Test word: Mangalore.
- Nasal quality sound occurs in cleft palate.
References
1-Allen AA, Heath JR, Mc Cord: Complete Prosthodontics; Problems, Diagnosis and Management. Mosby-Wolf, London, 1995.2- Beresin, V.E. and Schiesser, F. J.: The neutral zone in complete and partial dentures. 2nd ed. St. Louis, The C.V. Mosby Company: 1978.3- Coleman, R. D. and kaiser, W. B.: The Scientific Bases of Dentistry. Philadelphia, W. B. Sounders; 1966. 4- Craig, R.G.: Restorative Dental Materials. 8th ed. St. Louis, C. V. Mosby Company.5-Fenn, H.R.B.; Liddelow, K.P. and Gemson, A.B.: Clinical Dental Prosthetics. 2 ed. London, Staples; 1974.6- Geering AH,Kundert M , Kelesy C: Complete denture and overdenture Prosthetics. Theme medical publication Inc. New York, 1993.7-Grant AR, Heath JR, Mc Cord JF: Complete Prosthodontics; Problems, Diagnosis and Management. Mosby-Wolf, London, 1996.8- Heartwell, C.M. and Rhan, A.G.: Syllabus of Complete Dentures. 3rd ed. Philadelphia, Lea and Febiger; 1986.9- Sharry, J.J.: Complete denture prosthodontics. 3rd ed. NewYork, McGraw-Hill; 1974.
10- Sowter, J.B.: Dental laboratory technology: prosthodontic techniques. Chapel Hill, University of NorthCarolina; 1968.
11-Watt, D.M. and Mac Gregor, A.R.: Designing complete dentures. Philadelphia, W.B. Sounders; 1976.12- Winkler, S.: Essential of complete Denture Prosthodontics. 2nd ed. PSG Publishing Company; 1988.13- Zarb, G.A.; Bolender, C.L.; HicKey, J.C. and carlesson, G.E.: Boucher's ProthodonticTreatment for Edentulous Patients. 7th. Ed. St-Louis, The C.V.Mosby Company; 1990.N, B. All pictures in these slides are copied from the above references and from the internet.