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Dental Occlusion

Jan 23, 2017

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Page 1: Dental Occlusion
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Page 2: Dental Occlusion

By Prof. Mohamad HelalProf. Mohamad Helal

Head of Oral Biology Head of Oral Biology Department Department

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Def.Def. Contact relationship of the upper and lower teeth during various activities of the mandible (mastication, swallowing and speech) .

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•The relation of the upper and lower teeth when they are in maximum intercuspation during swallowing and the terminal position of the masticatory stroke.

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•Is a position of the mandibule in which the condyles are resting in the most retrusive unstrained position in the glenoid fossa and related anteriorly to the distal slope of the articular eminence.

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Why we study the occlusion?

The study of occlusion helps in the treatment of malocclusion, Temporomandibular Joint problems, in proper construction of dentures and other dental restorations (e.g., crown and bridge, etc…).

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To study the occlusion it must be include the following items:

1. Dental arch formation.2. Compensatory curves of dental arches.3. Compensatory curves of individual teeth.4. Angulations of individual teeth in relation to various planes.5. Functional form of the teeth at their incisal and occlusal

thirds.6. Facial relation of each tooth in one arch to its antagonist in

centric occlusion.7. Occlusal contact and intercuspation of all teeth of one arch

with those in the opposing arch in centric occlusion.8. Occlusal contact and interaction of all teeth during various

functional movements.

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1. Dental arch formation: Outline of the maxillary arch is larger than mandibular arch

• So, maxillary teeth overhang the mandibular teeth when the teeth are in centric occlusion

•Permits overbite and overjet relation ship

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OverbiteOverbite: vertical relation of the upper teeth to the lower teeth in centric occlusion .(increase efficiency of ant. teeth in bitingOver jetOver jet: horizontal relation of the upper teeth to the lower teeth in centric occlusion .(increase duration of occlusal contact in protrusive and lateral movements in incision and mastication )

Importance:Importance:•Prevent soft tissue biting•Guide the mandible through various lateral movement

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Overbite enables the disclusion of the posterior teeth during food incision and increases the efficiency of the anterior teeth in biting well.

Overjet increases duration of occlusal contact in protrusive and lateral movements in incising and mastication.

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From occlusal aspect the outline following labial and lingual surfaces confirmed to a parabolic curves. parabolic curves.

• the dental arches have three segments: the dental arches have three segments:

1.1.Anterior segment Anterior segment : semicircularsemicircular line passing along facial surfaces of anterior teeth.

2.2.Middle segment Middle segment : straightstraight line continuous with semicircular segment , include 1st , 2nd , M half of 1st molar.

3.3.Posterior segment Posterior segment : straightstraight line which is parallel to the median plane e including distobuccal half of 1st molar, B of 2nd and 3rd molars.

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Phases in development of dental arches :

11stst phase phase: : 6•6 years • 1st permanent molar take place post. to 2nd deciduous molar •Due to jaw growth Lead to : • 1- increase chewing efficiency 2- Serve to back up the deciduous teethMandibular one erupt firstly and max. one to established occlusion•1st permanent molar corner stone corner stone

2nd phase: 2nd phase: 1,2•Central and lateral lingual to the deciduous predecessors.

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3rd phase:3rd phase: 4,5

•1st and 2nd premolar take place of deciduous molar. •Primate space the size of premolars are smaller than the larger teeth they replace.

(Leeway space)

4th phase: 3,7The canines (Keystones) and 2nd molars emerge. The forcing of the canine bet. Incisors & 1st premolars in both jaw with backing effect of 2nd molar

5th phase:5th phase: 8•3rd molar distal to the 2nd molar.

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Leeway spaceLeeway space

• The erupting premolars are smaller in mesiodistal dimension than the primary molars.

• The difference in sizes between the premolars and primary molars as well as the deciduous canines called

“Leeway space’.

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The average mesiodistal size of the deciduous molars in that area is 47mm, which when compared with the premolars dimension of 42.2 mm, indicates an average gain of 4.8 mm in available space.

The leeway space must be utilized for alignment of the lower incisors as these teeth erupt with an average of 1.6 mm of crowding. The remainder of the space will be utilized by the mandibular molar.  

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This movement of the mandibular molars may correct an end-to-end molar relationship (normal for the mixed dentition) into a normal molar relationship in the permanent dentition, i.e., the mesiolingual cusp of the maxillary first molar occludes in the central fossa of the mandibular molar. This relationship is discussed later on.

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2- Compensatory Curvatures of the dental arches (Curved Occlusal Planes):

The significant of these curve as guidance for mandible Movement to complement the condyle paths and

for balance of mandible

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•Curve of Spee• Sagittal planes.

• Incisal Ridges of the anterior teeth and the B cusps of the posterior teeth follow a curve which end at the anterior surface of the condyle.

• when the arches were observed from a point opposite 6.

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Curve of Wilson

• Coronal plane.

• The occlusal surfaces of posterior teeth conform to a curved plane.

• The crowns of mandibular posterior teeth must incline to the lingual while the crowns of maxillary posterior teeth must incline toward the buccal.

• Deeper posteriorly molars inclination is greater than that of the premolar .

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Curve of Monson

• Combination of curve of Spee and the curve of Wilson. • coronal and sagittal planes.

• concave for the mandibular arch and convex for the maxillary arch. • in centric occlusion form a segment of a sphere of 4 inches radius with the center of the sphere at the glabella

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Bonwill Triangle Bonwill Triangle

• Describe the mandible and found that the mandibular dental arch adapts itself to an equilateral triangle of 4 inches length.

• Apex at the mesial contact area of the lower central incisors

• Angles of the base at the centers of each condyle

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Importance of compensatory curves:

Guidance for the mandible movement to complement the path of condyles for balance of the mandible.

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3- Compensating curvatures of individual teeth :

long axis of post. Teeth are not To a horizontal plane but show axial curvature

importance : 1- stability of teeth to resist force of mastication . 7, 8 distally inclined to prevent any distal drift of the posterior teeth.

7,8 mesially inclined to strike the maxillary molar

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3. Compensating curvatures of 3. Compensating curvatures of the individual teeth:the individual teeth:

When we observed the When we observed the dissected human jaw dissected human jaw with their roots with their roots exposed prove that exposed prove that the long axis of the long axis of posterior teeth are posterior teeth are not perpendicular to not perpendicular to a horizontal plane a horizontal plane but show axial but show axial curvature. This curvature. This curvature is essential curvature is essential for stability of teeth for stability of teeth in the dental arches in the dental arches to resist forces of to resist forces of mastication. mastication.

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The maxillary 2The maxillary 2ndnd &3&3rdrd molars have molars have distal inclination distal inclination to prevent any to prevent any distal drift of distal drift of posterior teeth posterior teeth while mandibular while mandibular 22ndnd & 3 & 3rdrd molar molar are inclined are inclined mesially to strike mesially to strike the maxillary the maxillary molars with a molars with a mesial direction mesial direction of forceof force

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4- Angulations of individual teeth 4- Angulations of individual teeth in relation to various planes in relation to various planes

The inclination of a The inclination of a tooth from a tooth from a vertical axis in vertical axis in mesiodistal and mesiodistal and faciolingual faciolingual directionsdirections

1- upper anterior: 1- upper anterior: FL inclined lingualFL inclined lingual

MD 1&2 inclined MD 1&2 inclined slightly mesial but slightly mesial but canine toward canine toward distaldistal

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Def Def . Inclination of the tooth from a vertical axis in a MD and FL direction.

(Considered root inclination so the crown inclined in opposite direction ).

importance: importance: Proper occlusal function ( each tooth must be placed at the angle that best withstand forces during function )

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2-Maxillary premolars are slight lingual in FL, Distal in MD3-Maxillary Molars roots have lingual inclination with distal inclination

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4-Mandibular 4-Mandibular anterior have anterior have greet lingual greet lingual root inclination root inclination in FL. In MD in FL. In MD incisors are incisors are nearly straight nearly straight or minor root or minor root inclination inclination while canine while canine has distal root has distal root inclinationinclination

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5- Mandibular 5- Mandibular premolars In MD premolars In MD have distal have distal inclination but in inclination but in FL 1FL 1stst premolar premolar incline lingually. incline lingually. But 2But 2ndnd premolars premolars is offset buccallyis offset buccally

6-Mandibular 6-Mandibular molars moderate molars moderate to great buccal to great buccal and distal toot and distal toot angulationsangulations

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Frontal view of the angulation of mandibular teeth:

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Frontal view of the angulation of maxillary teeth:

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Sagittal view of the angulation of maxillary &

mandibular teeth:

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FL angulations

All teeth have lingual root inclination except the 2nd PM and mandibular M have buccal root inclination

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MD angulations All teeth have distally root inclination except the upper incisors teeth have slight mesially root inclination and the lower incisors have slight mesial or straight .

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5. Functional form of the teeth at their 5. Functional form of the teeth at their incisal and occlusal thirdsincisal and occlusal thirds

There are no flat planes on the incisal or There are no flat planes on the incisal or occlusal surface of any of the teeth unless occlusal surface of any of the teeth unless they are created by wear or accident. they are created by wear or accident.

The cusps and incisal ridges acts as cutting The cusps and incisal ridges acts as cutting blades when they are come to contact in blades when they are come to contact in centric occlusion, the concave surface centric occlusion, the concave surface opposing the ridges in circumscribed points opposing the ridges in circumscribed points or areas and spaces appear all around this or areas and spaces appear all around this point which act as spillways or escapement point which act as spillways or escapement spacespace

So, this escapement space is provided in So, this escapement space is provided in teeth by the form of cusps, ridges, DG, IS teeth by the form of cusps, ridges, DG, IS

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• Provided in teeth by cusps, ridges, DG , interdental spaces .• its location and form differ when occlousal relation is

changed.• less space in centric occlusion and large space in lateral

relation .

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The location and form the escapement The location and form the escapement are changed when the occlusal are changed when the occlusal relation is changesrelation is changes

In centric occlusion with less In centric occlusion with less escapement space available but in escapement space available but in lateral relation the escapement is lateral relation the escapement is increased but the number of contact increased but the number of contact point is decreasedpoint is decreased

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6&7. The relation of each tooth in 6&7. The relation of each tooth in one arch to its antagonist in the one arch to its antagonist in the opposing arch in centric occlusionopposing arch in centric occlusionCentric occlusion It is relation of the upper and lower teeth when they are intercuspated together and the condyle are in resting in most retrusive position in the glenoid fossa.

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11stst permanent maxillary molar followed by permanent maxillary molar followed by mandibular one are a key of occlusion mandibular one are a key of occlusion why??why??

-1-1stst tooth permanent erupted in oral tooth permanent erupted in oral cavitycavity

-Largest in dental arch-Largest in dental arch -Guided by its position the deciduous -Guided by its position the deciduous

teethteeth -Have no predecessors-Have no predecessors -Maxillary one more accurate than -Maxillary one more accurate than

mandibular because it attached to fixed in mandibular because it attached to fixed in base of skullbase of skull

-In normal jaw relations and when teeth -In normal jaw relations and when teeth are of normal size and in the correct are of normal size and in the correct position, the mesiobuccal cusp of the position, the mesiobuccal cusp of the maxillary first molar occludes in the maxillary first molar occludes in the mesiobuccal groove of the mandibular first mesiobuccal groove of the mandibular first molar. This normal relationship of these molar. This normal relationship of these two teeth is called the two teeth is called the key of occlusionkey of occlusion. .

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key of occlusionkey of occlusion

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ANGLES CLASSIFICATION.\Angle was a dentist ANGLES CLASSIFICATION.\Angle was a dentist who developed a classification of normal and who developed a classification of normal and

abnormal ways teeth meet into centric occlusion.abnormal ways teeth meet into centric occlusion.Angle came up with three Angle came up with three

classes, Class I, II and III classes, Class I, II and III 1-Class I patient's profile is 1-Class I patient's profile is

characterized as normal. characterized as normal. 2-Class II patient's profile is 2-Class II patient's profile is

deficient in chin length and deficient in chin length and characterized as a retruded characterized as a retruded (retrognathic) profile. (retrognathic) profile.

3-Class III patient's profile is 3-Class III patient's profile is excessive in chin length and excessive in chin length and characterized as protruded characterized as protruded (prognathic) profile. (prognathic) profile.

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Class I

Class II

Class III

Angle’s Classification:Angle’s Classification:

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The centric relation of the teeth in The centric relation of the teeth in centric occlusion :centric occlusion :Permanent toothPermanent tooth

- The median plane is coincident The median plane is coincident in two jawsin two jaws

- Upper tooth has labial relation Upper tooth has labial relation to lower incisor in centricto lower incisor in centric

- Incisal ridges is free of - Incisal ridges is free of contact and has labial relation contact and has labial relation to labioincisal portion of lower to labioincisal portion of lower central incisorcentral incisor

- Cingulum above the lingual - Cingulum above the lingual embrasure of 1&2 lower incisorembrasure of 1&2 lower incisor

- Mesial outline is in line with - Mesial outline is in line with the mesial outline of lower the mesial outline of lower laterral incisorlaterral incisor

The distal outline is centered The distal outline is centered above labial surface of lower 1 above labial surface of lower 1 incisorincisor

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6- Facial and lingual Relations of Each Tooth in 6- Facial and lingual Relations of Each Tooth in One Arch to Its Antagonist in the Opposing Arch in One Arch to Its Antagonist in the Opposing Arch in Centric Occlusion.Centric Occlusion.

•In centric occlusion, each tooth occludes with two teeth in the opposing arch, except the mandibular central incisors and the maxillary third molars.

•Importance:Importance: 1.Prevent the over eruption of the teeth of the opposing arch. 2.prevent the mesial migration of the teeth in the same arch. 3.Distribute occlusal forces to several teeth.

mesial migration

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Tooth Alignment and Occlusion Tooth Alignment and Occlusion Normal Interarch RelationshipsNormal Interarch Relationships

The mandibular first molar is The mandibular first molar is positioned mesial to the maxillary positioned mesial to the maxillary first molarfirst molar

Interarch relationship of opposing teeth Modified after Okeson Fig. 3-21

Contact Relationships- Contact Relationships- Occlusal Occlusal contacts of posterior teethcontacts of posterior teeth

The mesiobuccal cusp of the The mesiobuccal cusp of the mandibular first molar occludes in mandibular first molar occludes in the embrasure between the the embrasure between the maxillary second premolar and the maxillary second premolar and the first molarfirst molarThe mesiobuccal cusp of the The mesiobuccal cusp of the maxillary first molar is opposite maxillary first molar is opposite the mesiobuccal (buccal) groove of the mesiobuccal (buccal) groove of the mandibular first molarthe mandibular first molarThe mesiolingual cusp of the The mesiolingual cusp of the maxillary first molar occludes in maxillary first molar occludes in the central fossa of the mandibular the central fossa of the mandibular first molarfirst molar

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Tooth Alignment and Occlusion Tooth Alignment and Occlusion Normal Interarch RelationshipsNormal Interarch Relationships

Normal buccolingual relationship of the molars Modified after Okeson Fig. 3-12

Normal buccolingual Normal buccolingual relationshiprelationship allows for allows for

efficient use of musculature in efficient use of musculature in chewing chewing

Minimizing trauma from cheek or Minimizing trauma from cheek or tongue-bitingtongue-biting

Functional cuspsFunctional cusps buccal cusps of Mandibular buccal cusps of Mandibular

posterior teethposterior teeth lingual cusps of Maxillary lingual cusps of Maxillary

posterior teethposterior teeth Centric cuspsCentric cusps Centric holding cuspsCentric holding cusps Stamp cuspsStamp cusps

Maintain vertical dimension or Maintain vertical dimension or distance between the maxilla and distance between the maxilla and mandiblemandible

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Tooth Alignment and Occlusion Tooth Alignment and Occlusion Normal Interarch RelationshipsNormal Interarch Relationships

Normal contacts in a Class I occlusion Modified after Okeson Fig. 3-23

Contact Relationships- Contact Relationships- MesiodistalMesiodistal• Occlusal contacts result from Occlusal contacts result from

functioning cusps contacting the functioning cusps contacting the opposing CF lineopposing CF line

• Contacts will occur inContacts will occur in• Central fossaeCentral fossae• Comparable to a mortar and pestleComparable to a mortar and pestle(臼杵)(臼杵)• Two dissimilar shaped surfaces Two dissimilar shaped surfaces

meet result in a spillway being meet result in a spillway being produced and masticatory efficiencyproduced and masticatory efficiency

SUMMARY STATEMENTSSUMMARY STATEMENTS

• Mesiolingual cusp of each Mesiolingual cusp of each maxillary molar occludes in the maxillary molar occludes in the central fossa of the opposing central fossa of the opposing mandibular molarmandibular molar

• Mesiobuccal cusp of each Mesiobuccal cusp of each mandibular molar occludes on mandibular molar occludes on the mesial marginal ridge of the mesial marginal ridge of the opposing maxillary molarthe opposing maxillary molar

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Tooth Alignment and Occlusion Tooth Alignment and Occlusion Normal Interarch RelationshipsNormal Interarch Relationships

Normal contacts in a Class I occlusion Modified after Okeson Fig. 3-23

Contact Relationships- Contact Relationships- MesiodistalMesiodistal

• Occlusal contacts result from Occlusal contacts result from centric cusps contacting the centric cusps contacting the opposing CF lineopposing CF line

• Contacts will occur inContacts will occur in• Central fossaeCentral fossae• Comparable to a mortar and Comparable to a mortar and

pestlepestle• Two dissimilar shaped surfaces Two dissimilar shaped surfaces

meet result in a spillway being meet result in a spillway being produced and masticatory produced and masticatory efficiencyefficiency

• Marginal ridges and Marginal ridges and embrasuresembrasures

• Cusp tip is very convexCusp tip is very convex• Marginal ridge is slightly convex Marginal ridge is slightly convex

(flat by comparison)(flat by comparison)• Actual contact is not cusp tip but Actual contact is not cusp tip but

0.5mm area around it0.5mm area around it

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Facial relation of the upper and lower Facial relation of the upper and lower teeth in centric occlusion teeth in centric occlusion

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lingual relation of the upper and lingual relation of the upper and lower teeth in centric occlusion lower teeth in centric occlusion

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Facial relation of the upper and Facial relation of the upper and lower teeth in centric occlusion lower teeth in centric occlusion

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lingual relation of the upper and lingual relation of the upper and lower teeth in centric occlusion lower teeth in centric occlusion

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Centric occlusion relation of the Centric occlusion relation of the deciduous teethdeciduous teeth

At age 3 years, the child has centric occlusion similar to permanent teeth

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Centric occlusion relation of the deciduous teeth: Centric occlusion relation of the deciduous teeth:

At age 3 years the child has centric occlusion similar to permanent teeth

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Tooth Alignment and Occlusion Tooth Alignment and Occlusion Contacts during Mandibular MovementsContacts during Mandibular Movements

Anterior guidance Okeson Fig. 3-30

Contact Relationships- Contact Relationships- PROTRUSIONPROTRUSION

• Potential posterior contacts in a Potential posterior contacts in a protrusive movement are the protrusive movement are the

• mesial inclines of mandibular mesial inclines of mandibular teeth (fossae and marginal teeth (fossae and marginal ridges)ridges)

• distal inclines of the maxillary distal inclines of the maxillary teeth (lingual cusps)teeth (lingual cusps)

• These contacts are undesirable These contacts are undesirable and are called and are called Protrusive Protrusive interferencesinterferences

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Tooth Alignment and Occlusion Tooth Alignment and Occlusion Contacts during Mandibular MovementsContacts during Mandibular Movements

Left laterotrusive movement (and right mediotrusive movement) Okeson Fig. 3-31

Contact Relationships- Contact Relationships- LATEROTRUSIVE LATEROTRUSIVE MANDIBULAR MOVEMENTMANDIBULAR MOVEMENT

• Desirable contacts in a left Desirable contacts in a left laterotrusive movement laterotrusive movement are maxillary buccal cusps are maxillary buccal cusps in contact with mandibular in contact with mandibular buccal cuspsbuccal cusps

Working Side

Non-working Side

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Tooth Alignment and Occlusion Tooth Alignment and Occlusion Contacts during Mandibular MovementsContacts during Mandibular Movements

Left laterotrusive movement (and right mediotrusive movement) Okeson Fig. 3-31

Contact Relationships- Contact Relationships- LATEROTRUSIVE LATEROTRUSIVE MANDIBULAR MOVEMENTMANDIBULAR MOVEMENT

• Other contacts that may Other contacts that may occur includeoccur include

• WORKING SIDE WORKING SIDE (LATEROTRUSIVE) (LATEROTRUSIVE) INTERFERENCESINTERFERENCES

• Outer inclines of maxillary Outer inclines of maxillary lingual cuspslingual cusps

• Inner inclines of Inner inclines of mandibular lingual cuspsmandibular lingual cusps

• NON-WORKING NON-WORKING (MEDIOTRUSIVE) (MEDIOTRUSIVE) INTERFERENCESINTERFERENCES

• Inner inclines of maxillary Inner inclines of maxillary lingual cuspslingual cusps

• Inner inclines of Inner inclines of mandibular buccal cuspsmandibular buccal cusps

Working Side

Non-working Side

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8-The Occlusal Contact and Intercusp 8-The Occlusal Contact and Intercusp Relations of all the Teeth During the Various Relations of all the Teeth During the Various

Functional mandibular movements. Functional mandibular movements.

Mandibular movements are: (rotating movement )

A.Symmetrical bilateral movements:A.Symmetrical bilateral movements:•Depression.•Elevation.•Protrusion.•Retrusion. B.Asymmetrical bilateral movements:B.Asymmetrical bilateral movements:•Right lateral movements.•Left lateral movements.

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8-the Occlusal Contact And Intercusp Relation 8-the Occlusal Contact And Intercusp Relation Of All Teeth During The Various Functional Of All Teeth During The Various Functional Mandibular MovemMandibular Movem6464ententThe mandibular movement are:The mandibular movement are:A) Symmetrical bilateral movement:A) Symmetrical bilateral movement:-Depression-Depression-Elevation-Elevation-Protrusion-Protrusion-Retrusion-RetrusionB) Asymmetrical bilateral movement:B) Asymmetrical bilateral movement: -Right lateral movement-Right lateral movement -Left lateral movement-Left lateral movement

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Rest position of the mandible : Rest position of the mandible : •When the mandible is at rest lower teeth are not in contact with the upper teeth as there is a space of 2 mm in-between the two arches freeway space . •Not a functional relation.

functional relations of functional relations of mandibular movements:mandibular movements:

1.Protrusive occlusal relation.2.Retrusive occlusal relation.3.Right occlusal relation.4.Left occlusal relation

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•The mandibular arch bears a forward, anterioranterior relation to its centric relationcentric relation with the maxillary arch. •Biting or shearing food material

1) 1) Protrusive occlusal relation:Protrusive occlusal relation:

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•Retrusion of the mandible,•the mandibular teeth will have posteriorposterior relation to centric occlusioncentric occlusion with the maxillary arch.

•Very limited and non functional movement.

2)Retrusive occlusal relation:2)Retrusive occlusal relation:

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•The mandibular dental arch is placed in a right right or left or left lateral relation to centric occlusion centric occlusion with the maxillary arch.

3) Right and left lateral occlusal relation:3) Right and left lateral occlusal relation:

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The masticatory cycle of posterior The masticatory cycle of posterior teeth:teeth:

•The working side shows the buccal cusps of maxillary and mandibular teeth to be in contact.

•The balancing side shows contact of lingual cusps of the maxillary teeth with the buccal cusps of mandibular teeth.

•Then both sides move to centric occlusion.

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Working side Working side Balancing side Balancing side

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The masticatory cycle of anterior teeth:The masticatory cycle of anterior teeth:

• In bitting

• the functioning side is located at the anterior teeth

• the balancing side at the posterior teeth.

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When the two jaw are not in occlusion, When the two jaw are not in occlusion, there is a space of 2mm (freeway there is a space of 2mm (freeway space) inbetween the two arches called space) inbetween the two arches called Rest positionRest position

1- Protrusive occlusal relation:1- Protrusive occlusal relation:Mandible arch bear a forward relation to Mandible arch bear a forward relation to

its centric relation with maxillary arch. its centric relation with maxillary arch. (biting or sheering food material)(biting or sheering food material)

2-Retrusive occlusal relation:2-Retrusive occlusal relation:Mandible will have posterior relation to Mandible will have posterior relation to

centric occlusion with upper arch. centric occlusion with upper arch. (limited and non functional movement)(limited and non functional movement)

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Right and left lateral movement: achieved Right and left lateral movement: achieved by lateral movement of mandible where is by lateral movement of mandible where is placed R or L to centric occlusionplaced R or L to centric occlusion

Musticatory cycle of posterior teeth: during Musticatory cycle of posterior teeth: during movement, the posterior teeth are not in movement, the posterior teeth are not in contact. So contact. So the working sidethe working side shows buccal shows buccal cusps of max. and mandibular to be in cusps of max. and mandibular to be in contactcontact

In In balanced side balanced side shows contact of lingual shows contact of lingual cusps of max. with buccal cusp of cusps of max. with buccal cusp of mandibular teeth then come to centric mandibular teeth then come to centric occlusion. These movement is called occlusion. These movement is called musticatory movement musticatory movement