Hind AlabbadiOcclusion sheet-10Date 20-4-2014

Occlusal Analysis

Clinical examination of occlusion:

It is an integral part of the wider more comprehensive examination of the *stomatognathic system.

we will talk mainly about the relationship between the teeth in this lecture, but keep in mind that it's part of TMJ examination: by palpation of muscle , Joint sounds , mandibular movement (Deviation & Deflection ) and so on, that we took about it before .

1- extra-oral examination : which include : TMJ and related structures ( muscles and ligaments ) .

2- intra-oral examination : static and dynamic structure of occlusal contact .

3- clinical study , radiographs and study models.

Extra-oral examination :

- Palpation of the TMJ and related structure of mastication .- Study of mandibular movement ( rang of opening & closure , path of movement like Deviation &

Deflection , and if there is restriction or limitation of movement). - Joint sounds (Clicking or Crepitation ).

Intra-oral examination :

Dental examination (history) :

- Study the number and position of teeth :Number if there is any missing teeth, is it all permanent or there is any primary teeth !Position if there is rotated tooth, tilted or lingually inclined tooth.

- Detection of anomalies of tooth form and structures for example big shape lateral incisors, rotated teeth , small size max molar or over size man molar .

- States of teeth if there is caries, wear or extraction.- pathogenesis of hard and soft tissues : hard tissue caries infections soft tissue hyperkeratosis , ulcers.

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Dental examination(history). statics of occlusal structures. dynamic occlusal structures. arch organization (intra-arch).

* In anatomy, the stomatognathic system consists of the mouth, jaws, and closely associated structures structures.

Hind AlabbadiOcclusion sheet-10Date 20-4-2014

static of occlusal structures :

As a definition they are parts of occlusal tape or lingual surfaces of teeth or cusp tips that come in contact with each other in centric occlusion i.e. only when we close our mouth not during function. And we look for cusp tips (functional), internal cusp ridges, marginal ridges of maxillary and mandibular teeth.

What is the function of statics occlusal structures

1-stability. ( each time the teeth would come in contact at the same point, so this would give the mandible its stability by gauging the mandible each time with the same position).

2-fixing the centric occlusion position.

3-distribution of occlusal stresses axially (all teeth under axial loading ).

4-masticatory functions.

What do we observe

- Mechanical tooth loss ( abrasion , fracture and wear of the teeth ).- Type of occlusion whether it is cusp to cusp , cusp to fossa or cusp to marginal ridge . ( here when we

examine the occlusion by mean of articulating paper, the points must be simultaneous , simultaneous homogenous "equal in intensity" in both sides and in all the teeth , if there is heavy points that’s mean of loading in that tooth …

- Changes in occlusal morphology or tooth contact would effect on occlusal stability ,masticatory functions and closure interferences.

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Hind AlabbadiOcclusion sheet-10Date 20-4-2014

dynamic occlusal structures:

- incisal border of mandibular incisors (incisal edges ).- cusps of the canines because those determine the canine guidance .- lingual surfaces of the maxillary anterior teeth those are the surfaces against which the movement

occurs. And you know when patient moves his mandible forward no contact must be appear on posterior teeth.

What is the function of dynamic occlusal structures

1- guiding for the mandibular movement.2- the masticatory functions (the incision of food occurs on incisors while mastication of food through

lateral excursions).

What do we observe

functional healthy anterior guidance:Functional we can incise food and speak normally.Healthy No any signs of mobility , wear in anterior teeth , disocclusion on posterior teeth and so on

The importance for occlusal analysis :- alteration in static structures influence the occlusal stability . eg. if there is a heavy contact on one tooth may lead to move it.- alteration in dynamic structures could result in functional occlusal interferences and consequent problem in the stomatognathic system. eg. If there is over erupted tooth this will interfere with lateral movement.

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Hind AlabbadiOcclusion sheet-10Date 20-4-2014

arch organization (intra-arch):- Observation of the anomalies of position such as rotations, drifting of teeth that could result on occlusal interferences.

We know that the teeth are in constant movement ie. each tooth is maintained within the arch by its neighbors ( tongue , cheeks , adjacent teeth the one mesial and the one distal and the opposing tooth ) if any one of these is lost the movement will occurs.

-Observation of the occlusal curves in sagittal and frontal plane

)curve of spee and curve of wilson.(

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eg. Paralysis of tongue (in old pt. or whatever) the teeth will move inward or toward inside.

eg. Mesial neighbor was extracted so the tooth will go mesialy by tiling or moving .

eg. Extraction of opposing tooth will lead to over eruption and tilting of the adjacent teeth.

eg. rotation of the teeth usually occurs in max 2nd premolar or man premolars if buccal cusp becomes mesially for example.

This will change the arrangement of the teeth in the arch thus change the curve

of spee i.e.( interferences )

Hind AlabbadiOcclusion sheet-10Date 20-4-2014

Arch organization (inter-arch):

maximum intercuspation position :

- It is a stability of centric occlusion is maintained by simultaneous bilateral homogenous contacts on all posterior teeth mainly and anterior teeth to a lesser extent .

By using articulating paper and ask the pt. to tap the teeth, we should see even contact on all teeth directed along the long axis, because the contact determined the maximum interception position ( Centric occlusion position )

- Rapid closure of the mandible from open position to maximum intercuspation and regularity of movement and reproducibility.

- palpation of elevation muscles during closure (asynchronism and asymmetry) we palpate muscles in both sides, if there is hypertonicity (spasm) in one of them ,that means there is either interferences in CO or problems in TMJ .

- palpation of the teeth once closure occurs (fremitus ) we put our finger on the buccal side of the tooth and ask the patient to close , if the tooth moves when there is a contact with the opposing one is called : fremitus ( because the tooth under heavy contact so more stress on it )

displacement between centric relation and centric occlusion :

- Measuring the anterioposterior and lateral aspects of the shift by marking vertical and horizontal lines on the incisors (magnitude and direction) , by these steps :

1-we ask the patient to close in centric occlusion then we draw vertical line to determine the mid line of maxillary teeth in relation to mandibular teeth and another horizontal line of how much max incisor overlap with man incisor.

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maximum intercuspation position displacement between CR and CO. Examination of anterior guidance. Examination of vertical the dimension of occlusion

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Hind AlabbadiOcclusion sheet-10Date 20-4-2014

2-we ask the patient to move backward into centric relation then we determine the amount of displacement, also we observe the mid line if it change or not.

- When a lateral component exists then this is indicative of a problem in the centering of the mandible. if more than 2 mm in magnitude it is usually associates with signs and symptoms.(Normally movement from CO to CR should be straight without any lateral movement).

Examination of anterior guidance : -presence of harmonious anterior guidance (incisal and lateral).

we put articulating paper and ask the patient to do protrusive movement , We look to maxillary central and laterals which must have lines equal in intensity and equally distributed on anterior teeth. By that it is important to check the protrusive movement and insure that is no interference anteriorly to avoid any problems.

Note : we can examine the anterior guidance on semi adjustable articulator. By taken alginate impression for constrict the study cast for both max and man then we do face bow registration then we program the articulator .

Examination of vertical the dimension of occlusion:- Height of the lower third of the face important for swallowing, speaking and esthetic.

Swallowing : we have to close the anterior mouth area for efficient swallowing , so if the lower facial height small so the patient cant swallow , also if it's very high the lips separatedSpeaking : there will be problem in phonetics (certain sound ) in very short vertical dimension or high lower facial height , it is more important in full mouth rehabilitation like complete denture .

- Loss of the vertical dimension of occlusion could result either from (a or b): a. Loss or migration of teeth.b. Pathologic loss of tooth structure.

Note this case of loss of lower facial height ( no stops in CO ). And see the over erupted canine and it's touching the mandible, and also mandibularincisor are touching maxilla .

Another case that's due to loss of tooth structure not loss of teeth .

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Hind AlabbadiOcclusion sheet-10Date 20-4-2014

- This could cause problems from an esthetic point of view as well as problems in the neuromuscular system .

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We should also observe parafunctional habits:

- Habits involving the type of swallowing such as infantile swallowing , nail biting , lip and tongue biting can have an influence on the occlusal stability and function.

1st example : infantile swallowing : infants when they swallow, they tend to push the tongue between the lips, because their tongue is large (must of the tongue in oral cavity in infant while in adult only 1\3 of the tongue in oral cavity ) So some people maintain this type of swallowing all through their life which will lead to make disturbances in anterior part of oral cavity due to present of constant pressure on anterior teeth.

2nd example : Bite on your pens will lead to make disturbances due to present of constant pressure on certain tooth.

- Could result in eventual changes in tooth morphology (either by loss or wear of tooth structure) and\or abnormal tooth position.

Occlusal analysis : use of articulators :

- It’s a complementary step to confirm our clinical observation ( i.e. After we do our clinical observation w fe ashya2 ma 2derna nshofha due to the Presence of cheeks , lips..etc we can use the articulator .

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Hind AlabbadiOcclusion sheet-10Date 20-4-2014

Occlusal equilibration ( Selective grinding ) :

If we find interferances in certain area during examination eg. high Point ( high contact ) what do we do ? relieve it by bur and allow the patient to go ! Of course no. Why? بنضمن ما فإحنا ؛ عالي االطباق فيها تانية منطقة تطلعلنا ممكنwhat do we do actually ? Using articulator .

From the slide : - Occlusal equilibration ( Selective grinding ) or any type of occlusal modification should be done on the articulator systematically before any irreversible changes are done in the mouth.- For this we need accurate study models taken in alginate impression and then mounted on the articulator (semi adjustable ) using face bow registration in the centric relation position.

Criteria of functional occlusion:

1- Minimal shift between centric occlusion and centric relation.2- Harmonious vertical dimension of occlusion.3- Stable contacts in maximum intercuspation position ( multiple bilateral homogenous and

simultaneous contacts on maximum number of posterior teeth) .4- Functional anterior guidance free of posterior interferences.

Good luck --

Done by: Hind Alabbadi.

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