**OCCLUSION** **Keys for Optimal Occlusion** DR V MATSUBARA Image of a dental model showing occlusion, with text overlay and university branding. # **OCCLUSION: Keys for Optimal Occlusion** **OCCLUSION** LEARNING OUTCOMES - Identify pathological adaptations caused by malocclusion. - Explain the movements of condyles during protrusion and lateral excursion of the mandible. - Define Centric Relation, Maximum Intercuspal Position, and Centric Occlusion. - Define and discuss the criteria for the ideal occlusion. - Describe the three types of guidance for lateral movements of the mandible. # **LEARNING OUTCOMES** - Identify pathological adaptations caused by malocclusion. - Explain the movements of condyles during protrusion and lateral excursion of the mandible. - Define Centric Relation, Maximum Intercuspal Position, and Centric Occlusion. - Define and discuss the criteria for the ideal occlusion. - Describe the three types of guidance for lateral movements of the mandible. # OCCLUSION ## SIGNIFICANCE Dental treatments inevitably affect the occlusion - Tooth restoration - Tooth extraction - Tooth movement - Tooth adjustment Many patients present with a form of occlusal problems - Tooth wear (attrition, erosion, abrasion, abfraction) - Overloading - Fractured cusp or restoration - Cracked tooth # **OCCLUSION** ## **SIGNIFICANCE** Dental treatments inevitably affect the occlusion: - Tooth restoration - Tooth extraction - Tooth movement - Tooth adjustment > [!info] Post-Extraction Changes > Following an extraction, it is important to inform the patient that adjacent teeth may drift into the edentulous space and opposing teeth may supra-erupt. This explains the need for prosthetic replacements like bridges or dentures. Many patients present with a form of occlusal problems: - Tooth wear (attrition, erosion, abrasion, abfraction) - Overloading - Fractured cusp or restoration - Cracked tooth **OCCLUSION** SIGNIFICANCE - Little evidence suggesting that a change in occlusion will precipitate morphological changes within TMJs - The most likely adaptation occur in teeth and their supporting structures For example: tooth wear, tooth movement and fracture - Little evidence suggesting that a change in occlusion will precipitate morphological changes within TMJs - The most likely adaptation occur in teeth and their supporting structures For example: tooth wear, tooth movement and fracture **OCCLUSION** **Attrition** Incisors wear Possible causes: - Lack of posterior tooth support - Abrasive restorative material - Bruxism ## **Pathological Adaptations** ### **Attrition** Incisors wear > [!info] > Severe wear of the anterior teeth is often a result of a lack of posterior support, which concentrates forces on the front. This is exacerbated when combined with bruxism and erosion. **Possible causes:** - Lack of posterior tooth support - Abrasive restorative material - Bruxism # OCCLUSION ## Attrition **Generalized** - Severe wear, fractured teeth - Dentoalveolar compensation: limits vertical space for dental restoration **Attached gingiva** #### **Generalized Attrition** - Severe wear, fractured teeth - Dentoalveolar compensation: limits vertical space for dental restoration > [!info] Compensatory Mechanism > In cases of long-term grinding, a compensatory mechanism can occur where cementum and bone are deposited at the apex of the tooth socket. > This leads to a gradual super-eruption of the teeth, maintaining the vertical dimension of occlusion (VDO) despite significant wear of the occlusal surfaces. > Restoring these cases is complex because simply “opening the bite” is not an option, as the VDO is already correct. Treatment may require elective endodontics and crown lengthening to create space for restorations. **Attached gingiva** **OCCLUSION** **Splayed teeth** Possible causes - Loss of posterior teeth combined with periodontal problems (reduced periodontal support) - Over contouring of palatal surface of maxillary incisors or incisal/labial surfaces of mandibular incisors. Soreness of anterior teeth precede tooth movement ### **Splayed teeth** **Possible causes:** - Loss of posterior teeth combined with periodontal problems (reduced periodontal support) - Over contouring of palatal surface of maxillary incisors or incisal/labial surfaces of mandibular incisors. Soreness of anterior teeth precede tooth movement **OCCLUSION** **Sore teeth** Overcompression of periodontal ligament can cause considerable pain on biting **Causes** - Premature occlusal contacts (occlusal overload) - Occlusal interferences Diagram of a human jaw showing occlusal contacts and periodontal ligament stress points. ### **Sore teeth** Overcompression of periodontal ligament can cause considerable pain on biting > [!tip] Clinical Application > It is critical to perform a thorough occlusal adjustment after placing a restoration, especially while the patient is numb and cannot provide accurate feedback. > - ==**Articulating Paper Interpretation:** A heavy contact will often appear as a ring or perforation in the paper, not just a small dot. These heavy marks must be adjusted until the contacts are even across all teeth. Removing all marks would take the tooth out of occlusion.== **Causes:** - Premature occlusal contacts (occlusal overload) - Occlusal interferences **OCCLUSION** **Sensitive teeth** Hypersensitivity might result from occlusal overload Causes: - restoration causing occlusal interferences ### **Sensitive teeth** Hypersensitivity might result from occlusal overload > [!info] > Occlusal overload can also lead to pulp hypersensitivity, causing the patient to experience sensitivity to temperature changes (e.g., cold). > Before assuming a filling is leaking or has recurrent decay, the occlusion should always be checked and adjusted, as this can often resolve the symptoms. **Causes:** - restoration causing occlusal interferences # OCCLUSION **Hypermobility** Pathological adaptation ## Causes - Restoration causing occlusal interferences - All mobile teeth should be assessed to rule out deflective contacts or occlusal overload as a factor in the cause of the mobility ### **Hypermobility** Pathological adaptation **Causes:** - Restoration causing occlusal interferences - All mobile teeth should be assessed to rule out deflective contacts or occlusal overload as a factor in the cause of the mobility > [!info] > This is a mid- to long-term consequence of excessive occlusal stress, particularly from lateral interferences. The tooth becomes “wobbly” as a protective mechanism. Radiographically, a widening of the PDL space may be visible. Treatment involves a precise occlusal adjustment to eliminate interferences, often by establishing proper canine guidance. # OCCLUSION **Tooth cracks** - crack lines routinely develop when a cusp is loaded with heavy occlusal forces - Can precedes tooth fracture **Cracked tooth syndrome** ### **Tooth cracks** - crack lines routinely develop when a cusp is loaded with heavy occlusal forces > [!warning] > Cracked tooth syndrome often presents as sharp pain specifically on biting down. It is essential to investigate the cause (e.g., occlusal overload, failing restoration) and consider preventative treatment, such as a crown or onlay, to protect the tooth from fracturing. - Can precedes tooth fracture **Cracked tooth > [!info] Prosthetic Reconstruction > Many patients require prosthetic treatment due to conditions like: > - ==**Occlusal Overload:** Lack of posterior support can put excessive stress on remaining teeth, leading to abfractions, cusp fractures, and cracked tooth syndrome.== syndrome** # OCCLUSION **Painful musculature** **Cause** - Deflective occlusal interferences that cause jaw joints to displace - Unbalanced muscle contraction ### **Painful musculature** **Cause:** - Deflective occlusal interferences that cause jaw joints to displace - Unbalanced muscle contraction > [!info] Mechanism > The brain subconsciously directs the mandible to shift away from the interference, creating a new habitual bite position. This results in an imbalanced contraction of the masticatory muscles, which over time causes soreness and fatigue. Treatment involves correcting the occlusion, sometimes after deprogramming the muscles with an occlusal splint. # Masticatory System ## Components 1. Teeth 2. Periodontal tissues 3. Articulatory apparatus Interconnected biomechanical system **CNS** **Muscles** **Articulation** **Teeth** Davies and Gray; 2000 # **Masticatory System** ## **Components** 1. Teeth 2. Periodontal tissues 3. Articulatory apparatus Interconnected biomechanical system **CNS** **Muscles** **Articulation** **Teeth** *Davies and Gray; 2000* # Masticatory System Function of each component 1. TMJs: guiding system 2. Dental occlusion: guiding system 3. Masticatory muscle: moving system ## **Function of each component** 1. **TMJs:** guiding system 2. **Dental occlusion:** guiding system 3. **Masticatory muscle:** moving system **TMJ** **Movements** 1. **Hinge movement:** * Rotation around the intra-condylar axis * Within the glenoid fossa * < 2 cm of movement 2. **Translation movement:** * Gliding against articular eminence * > 2 cm Two anatomical illustrations of the TMJ, labeled "Rotation" and "Translation". # **TMJ** ## **Movements** 1. **Hinge movement:** - Rotation around the intra-condylar axis - Within the glenoid fossa - < 2 cm of movement **TMJ** **Movements** 1. Hinge movement: - Rotation around the intra-condylar axis - Within the glenoid fossa - < 2 cm of movement 2. Translation movement: - Gliding against articular eminence - > 2 cm 2. **Translation movement:** - Gliding against articular eminence - > 2 cm > [!info] Bilaminar Zone > This is a highly vascular and innervated area posterior to the condyle. In a healthy joint, it is not compressed. In cases of anterior disc displacement, the condyle can compress this zone, causing pain. **TMJ** **Movement directions** ➢ **Protrusive movement** Both condyles are in similar gliding motion ➢ **Lateral movement** **Working side**: rotational movement around the vertical axis without leaving the glenoid fossa **Non-working side**: gliding movement against the articular eminence ## **Movement directions** - **Protrusive movement** - Both condyles are in similar gliding motion - **Lateral movement** - **Working side**: rotational movement around the vertical axis without leaving the glenoid fossa - **Non-working side**: gliding movement against the articular eminence **TMJ** **Excursive Movements** ➢ During a lateral excursion of the mandible, the major movement within the TMJs occurs on the non-working side: - The head of the condyle on the nonworking side moves forward, downward and medially - The angle of downwards movement is stablished by the ‘condylar angle’ - The angle of medial movement is known as the ‘Bennet angle’ ## **Excursive Movements** - During a lateral excursion of the mandible, the major movement within the TMJs occurs on the non-working side: - The head of the condyle on the nonworking side moves forward, downward and medially - The angle of downwards movement is stablished by the ‘condylar angle’ - The angle of medial movement is known as the ‘Bennet angle’ Protrusion Condylar angle (guidance inclination) ### **Condylar Guidance** Protrusion Condylar angle (guidance inclination) > [!info] > The downward path of the condyle during protrusive and lateral movements is dictated by the steepness of the articular eminence. On a semi-adjustable articulator, this is typically set to an average of **30 degrees**. A steeper condylar guidance results in more immediate disocclusion (separation) of the posterior teeth during movement. Lateral excursion Diagram showing lateral excursion of the mandible with labeled Bennet angle and Fisher angle, using colored arrows and 3D boxes to illustrate movement. Lateral excursion **Bennett angle** Bennett angle: formed between the sagittal plane and the average path of the advancing condyle as viewed in horizontal plane during lateral mandibular movement. Bennett movement = LATEROTRUSION Bennett angle Average of 15 degree ## **Bennett angle** **Bennett angle:** formed between the sagittal plane and the average path of the advancing condyle as viewed in horizontal plane during lateral mandibular movement. **Bennett movement** = LATEROTRUSION **Bennett angle** Average of 15 degree > [!note] Note on Fischer Angle > The same movement of the non-working condyle, when viewed from the **sagittal plane**, creates the **Fischer angle**. This angle exists because the roof of the glenoid fossa is concave both antero-posteriorly and medio-laterally. **Bennett angle** Bennett side shift (mandibular lateral translation): the medio-lateral movement of the mandible when viewed in the frontal plane during Bennett movement - Immediate Bennett side shift - IMMEDIATE MANDIBULAR LATERAL TRANSLATION - Progressive Bennett side shift - PROGRESSIVE MANDIBULAR LATERAL TRANSLATION ## **Bennett side shift** **Bennett side shift (mandibular lateral translation):** the medio-lateral movement of the mandible when viewed in the frontal plane during Bennett movement > [!info] > The movement on the working side is not pure rotation. The entire mandible also shifts laterally towards the working side. This bodily side-shift is called the **Bennett side shift** or lateral translation. - Immediate Bennett side shift - IMMEDIATE MANDIBULAR LATERAL TRANSLATION - Progressive Bennett side shift - PROGRESSIVE MANDIBULAR LATERAL TRANSLATION **Immediate and progressive Bennett angle** Diagram illustrating Immediate and Progressive Bennett side shift with labeled arrows and a jawbone model. **Immediate and progressive Bennett angle** Dental Occlusion Provided by whichever teeth touching the opposing teeth or analogs • Static occlusion • Dynamic occlusion # **Dental Occlusion** Provided by whichever teeth touching the opposing teeth or analogs - Static occlusion - Dynamic occlusion # Dental Occlusion **STATIC** - Maximal intercuspation - Centric relation/Centric occlusion - Freedom in centric - Extent of posterior tooth support - Overbite and overjet **DYNAMIC** - Protrusion - Lateral occlusion guidance - Canine guidance - Group function - Balanced occlusion (complete dentures) - Working and non-working sides interferences ## **Overview of Occlusal Concepts** ### **STATIC** - Maximal intercuspation - Centric relation/Centric occlusion - Freedom in centric - Extent of posterior tooth support - Overbite and overjet ### **DYNAMIC** - Protrusion - Lateral occlusion guidance - Canine guidance - Group function - Balanced occlusion (complete dentures) - Working and non-working sides interferences # Dental Occlusion ## STATIC OCCLUSION **Centric relation:** a maxillomandibular relationship in which the condyles articulate in the anterior-superior position against the posterior slopes of the articular eminences. - This position is independent of tooth contact - Reproducible *The Glossary of Prosthodontic Terms; 9th ed* ## **STATIC OCCLUSION** ### **Centric relation:** a maxillomandibular relationship in which the condyles articulate in the anterior-superior position against the posterior slopes of the articular eminences. - This position is independent of tooth contact > [!info] Clinical Significance > It is the primary reference point for mounting casts and fabricating prostheses for edentulous patients, as they lack a repeatable tooth-guided position. - Reproducible *The Glossary of Prosthodontic Terms; 9th ed* # Dental Occlusion ## STATIC OCCLUSION **Maximum intercuspal position (MIP)**: the complete intercuspation of the opposing teeth independent of condylar position - Bite of convenience - Habitual bite (position) **Centric occlusion**: the occlusion of opposing teeth when the mandible is in centric relation - In 90% of population MIP ≠ CO *The Glossary of Prosthodontic Terms; 9th ed* ### **Maximum intercuspal position (MIP):** the complete intercuspation of the opposing teeth independent of condylar position - Bite of convenience - Habitual bite (position) > [!info] > It is the most stable position for a dentate patient. ### **Centric occlusion:** the occlusion of opposing teeth when the mandible is in centric relation - In 90% of population MIP ≠ CO > [!info] > There is typically a small anterior-posterior slide from the initial contact in CO to the full bite in MIP. *The Glossary of Prosthodontic Terms; 9th ed* # Dental Occlusion ## STATIC OCCLUSION **Freedom in centric** Freedom in centric occlusion occurs when the mandible is able to move anteriorly for a short distance in the same horizontal and sagittal plane while maintaining tooth contact There is a flat region in the central fossa where opposing cusps contact that gives to the mandible freedom in eccentric movements (no interference) ### **Freedom in centric** Freedom in centric occlusion occurs when the mandible is able to move anteriorly for a short distance in the same horizontal and sagittal plane while maintaining tooth contact. There is a flat region in the central fossa where opposing cusps contact that gives to the mandible freedom in eccentric movements (no interference). > [!tip] > Restorations should be designed to allow for this freedom to avoid occlusal stress. # Dental Occlusion ## DYNAMIC OCCLUSION Refers to occlusal contacts that are made whilst the mandible is moving relative to the maxilla - The mandible is moved by the muscles of mastication - The pathways along which its moves are determined by two guidance systems (TMJ and dental occlusion) Illustration of a human skull with close-ups of the temporomandibular joint (TMJ) and teeth, highlighting dynamic occlusion. ## **DYNAMIC OCCLUSION** Refers to occlusal contacts that are made whilst the mandible is moving relative to the maxilla. - The mandible is moved by the muscles of mastication - The pathways along which its moves are determined by two guidance systems (TMJ and dental occlusion) > [!info] Anterior Guidance > The contact of the lower incisors against the palatal surfaces of the upper incisors during protrusive and lateral movements. > > **Relationship to Condylar Guidance:** A steep anterior guidance can compensate for a flat condylar guidance by creating more separation (disocclusion) of the posterior teeth during movement. This is a key principle in denture construction but is less modifiable in fixed prosthodontics. # Dental Occlusion ## DYNAMIC OCCLUSION - As the head of the condyle moves downwards and forwards, the mandible moves along a guidance pathway which is determined by the intraarticular disc and the articulatory surfaces of the glenoid fossa; - If teeth are touching during a protrusive or lateral movement of the mandible then those (touching) teeth are also providing guidance to mandibular movement; - Tooth contacts dictate the mandibular movement in occlusion. - As the head of the condyle moves downwards and forwards, the mandible moves along a guidance pathway which is determined by the intraarticular disc and the articulatory surfaces of the glenoid fossa; - If teeth are touching during a protrusive or lateral movement of the mandible then those (touching) teeth are also providing guidance to mandibular movement; - Tooth contacts dictate the mandibular movement in occlusion. **Dental Occlusion** **Criteria for Optimal Occlusion** 1) Mandibular stability: contact of inferior and superior teeth must stabilize the mandible in centric - Condyles are positioned within the glenoid cavity without stretching or compressing the ligament or articular disc - Bilateral and simultaneous occlusal contacts in centric (CR/MIP) # **Criteria for Optimal Occlusion** **1) Mandibular stability:** contact of inferior and superior teeth must stabilize the mandible in centric - Condyles are positioned within the glenoid cavity without stretching or compressing the ligament or articular disc - Bilateral and simultaneous occlusal contacts in centric (CR/MIP) # Dental Occlusion ## Criteria for Optimal Occlusion 2) Axial load: The occlusal load should be parallel to the long axis of the tooth Load is distributed equally throughout the periodontal ligament Diagram showing two teeth with blue arrows indicating vertical force along the long axis of the teeth. **2) Axial load:** The occlusal load should be parallel to the long axis of the tooth - Load is distributed equally throughout the periodontal ligament **Dental Occlusion** **Criteria for Optimal Occlusion** 3) During lateral excursions of the mandible, there is no interference on the working side **Types of guidance:** - Canine guidance - Group Function (total or partial) } Dentate - Balanced occlusion (bilaterally balanced occlusion) – Edentate **3) During lateral excursions of the mandible, there is no interference on the working side** ### **Types of guidance:** - Canine guidance - Group Function (total or partial) } Dentate - Balanced occlusion (bilaterally balanced occlusion) – Edentate # Dental Occlusion ## Criteria for Optimal Occlusion ### Lateral occlusion guidance **Canine guided (protected) occlusion** - A form of articulation in which the vertical and horizontal overlap of canine teeth disengage posterior teeth in excursive movements of the mandible - Complete disocclusion of posterior teeth during lateral movement *The Glossary of Prosthodontic Terms; 2005* ### **Lateral occlusion guidance** #### **Canine guided (protected) occlusion** - A form of articulation in which the vertical and horizontal overlap of canine teeth disengage posterior teeth in excursive movements of the mandible - Complete disocclusion of posterior teeth during lateral movement > [!success] Advantages > The canine is structurally suited to withstand heavy lateral forces. This scheme is considered ideal for the natural dentition and is simpler to achieve in restorative dentistry. *The Glossary of Prosthodontic Terms; 2005* # Dental Occlusion ## Criteria for Optimal Occlusion **Lateral occlusion guidance** **Canine guided (protected) occlusion** - Most widely accepted concept in restorative dentistry - Easier to reproduce - Canines are ideal guiding teeth Not indicated if the canines are compromised - Periodontally - Endodontically *The Glossary of Prosthodontic Terms; 2005* - Most widely accepted concept in restorative dentistry - Easier to reproduce - Canines are ideal guiding teeth Not indicated if the canines are compromised: - Periodontally - Endodontically *The Glossary of Prosthodontic Terms; 2005* # Dental Occlusion ## Criteria for Optimal Occlusion **Lateral occlusion guidance** **Group function occlusion (unilaterally balanced occlusion)** - Distribution of lateral forces to a group of teeth; - Multiple contacts between the maxillary and mandibular teeth in lateral movements on the working side whereby simultaneous contact of several teeth acts as a group to distribute occlusal forces - On lateral movements, the contacts are on the buccal cusps of the working side *The Glossary of Prosthodontic Terms; 2005* #### **Group function occlusion (unilaterally balanced occlusion)** - Distribution of lateral forces to a group of teeth; - Multiple contacts between the maxillary and mandibular teeth in lateral movements on the working side whereby simultaneous contact of several teeth acts as a group to distribute occlusal forces - On lateral movements, the contacts are on the buccal cusps of the working side > [!warning] Distinction from Interference > True group function involves a smooth, sequential contact of multiple teeth. If only the canine and a single posterior tooth (e.g., a second molar) are in contact, the molar contact is considered an **interference**, not group function. *The Glossary of Prosthodontic Terms; 2005* # Dental Occlusion ## Criteria for Optimal Occlusion **Lateral occlusion guidance** **Group function occlusion** - Non-working (balancing) side - no contacts - Widely accepted - May cause excessive load on posterior teeth - Difficult to establish The Glossary of Prosthodontic Terms; 2005 - Non-working (balancing) side - no contacts - Widely accepted - May cause excessive load on posterior teeth - Difficult to establish *The Glossary of Prosthodontic Terms; 2005* **Dental Occlusion** Criteria for Optimal Occlusion 4) During lateral excursions of the mandible, there is disocclusion in the non-working side Diagram showing upper and lower teeth with red dots indicating working contacts during lateral mandibular movement, with an arrow pointing right. **4) During lateral excursions of the mandible, there is disocclusion in the non-working side** # Dental Occlusion ## Criteria for Optimal Occlusion ### Interferences - Working and/or non-working side interferences - Can be observed clinically - Increase patient awareness of the restoration - Excessive horizontal and oblique forces will be applied on the restoration or natural teeth *The Glossary of Prosthodontic Terms; 2005* ### **Interferences** - Working and/or non-working side interferences > [!info] Types of Interferences > - ==**Working Side Interference:** A posterior contact on the working side that prevents the desired canine guidance or disrupts a smooth group function.== > - ==**Non-Working Side (Balancing) Interference:** Any tooth contact on the non-working side. These are particularly destructive as they place oblique, harmful forces on the teeth.== > - ==**Protrusive Interference:** A posterior tooth contact during a forward movement of the mandible.== - Can be observed clinically - Increase patient awareness of the restoration - Excessive horizontal and oblique forces will be applied on the restoration or natural teeth *The Glossary of Prosthodontic Terms; 2005* # Dental Occlusion ## Criteria for Optimal Occlusion **Lateral occlusion guidance** **Balanced occlusion (bilaterally balanced occlusion)** - Bilateral, simultaneous, anterior and posterior occlusal contact of teeth in centric and eccentric positions - At least 3 contact points: 2 posterior and 1 anterior *The Glossary of Prosthodontic Terms; 2005* ### **Lateral occlusion guidance** #### **Balanced occlusion (bilaterally balanced occlusion)** - Bilateral, simultaneous, anterior and posterior occlusal contact of teeth in centric and eccentric positions - At least 3 contact points: 2 posterior and 1 anterior > [!info] Purpose > The bilateral contacts provide stability to the denture bases, preventing them from tipping or losing suction during function. This scheme is destructive to natural teeth and should not be created in a dentate patient. *The Glossary of Prosthodontic Terms; 2005* # Dental Occlusion ## DYNAMIC OCCLUSION Lateral occlusion guidance **Balanced occlusion (bilaterally balanced occlusion)** - Useful for complete denture cases to prevent tipping of the denture - Cross arch balanced occlusion is not indicated for natural dentition **REASONS:** - Excessive wear was observed - Presence of balancing contacts can apply horizontal and oblique destructive forces on posterior teeth - Destructive effects on the non working side - Useful for complete denture cases to prevent tipping of the denture - Cross arch balanced occlusion is not indicated for natural dentition **REASONS:** - Excessive wear was observed - Presence of balancing contacts can apply horizontal and oblique destructive forces on posterior teeth - Destructive effects on the non working side # Dental Occlusion ## Criteria for Optimal Occlusion 5) During protrusion, there is disocclusion of posterior teeth - Protrusive or Anterior guidance 3D model of human dentition showing anterior teeth in protrusive position with posterior teeth disoccluded. **5) During protrusion, there is disocclusion of posterior teeth** - Protrusive or Anterior guidance # Dental Occlusion ## Mutually protected articulation - An occlusal scheme in which the posterior teeth prevent excessive contact of the anterior teeth in MIP; and anterior teeth disengage the posterior teeth in all mandibular excursive movements **MIP** **Laterotrusion/Protrusion** *The Glossary of Prosthodontic Terms; 2005* # **Mutually protected articulation** - An occlusal scheme in which the posterior teeth prevent excessive contact of the anterior teeth in MIP; and anterior teeth disengage the posterior teeth in all mandibular excursive movements > [!example] In simpler terms: > 1. ==In **maximum intercuspation (MIP)**, the posterior teeth are in firm, even contact to absorb the heavy vertical forces of chewing, thus protecting the anterior teeth.== > 2. ==In **all excursive movements** (protrusive and lateral), the anterior teeth (incisors and canines) contact and guide the mandible, causing the posterior teeth to disocclude. This protects the posterior teeth from harmful off-axis (oblique) forces.== **MIP** **Laterotrusion/Protrusion** *The Glossary of Prosthodontic Terms; 2005* **Dental Occlusion** Criteria for Optimal Occlusion 1) Mandibular stability 2) Axial occlusal load 3) During lateral excursions: no interference in the working side 4) During lateral excursions: disocclusion in the non-working side 5) During protrusion: disocclusion of posterior teeth ## **Summary: Criteria for Optimal Occlusion** 1) Mandibular stability 2) Axial occlusal load 3) During lateral excursions: no interference in the working side 4) During lateral excursions: disocclusion in the non-working side 5) During protrusion: disocclusion of posterior teeth Book cover of "Management of Temporomandibular Disorders and Occlusion" by Jeffrey P. Okeson Thank you!! Thank you! [[MR4 OptimalOcclusion.pdf#page=1|MR4 OptimalOcclusion, p.1]] [[MR4 OptimalOcclusion.pdf#page=2|MR4 OptimalOcclusion, p.2]] [[MR4 OptimalOcclusion.pdf#page=3|MR4 OptimalOcclusion, p.3]] [[MR4 OptimalOcclusion.pdf#page=4|MR4 OptimalOcclusion, p.4]] [[MR4 OptimalOcclusion.pdf#page=5|MR4 OptimalOcclusion, p.5]] [[MR4 OptimalOcclusion.pdf#page=6|MR4 OptimalOcclusion, p.6]] [[MR4 OptimalOcclusion.pdf#page=7|MR4 OptimalOcclusion, p.7]] [[MR4 OptimalOcclusion.pdf#page=8|MR4 OptimalOcclusion, p.8]] [[MR4 OptimalOcclusion.pdf#page=9|MR4 OptimalOcclusion, p.9]] [[MR4 OptimalOcclusion.pdf#page=10|MR4 OptimalOcclusion, p.10]] [[MR4 OptimalOcclusion.pdf#page=11|MR4 OptimalOcclusion, p.11]] [[MR4 OptimalOcclusion.pdf#page=12|MR4 OptimalOcclusion, p.12]] [[MR4 OptimalOcclusion.pdf#page=13|MR4 OptimalOcclusion, p.13]] [[MR4 OptimalOcclusion.pdf#page=14|MR4 OptimalOcclusion, p.14]] [[MR4 OptimalOcclusion.pdf#page=15|MR4 OptimalOcclusion, p.15]] [[MR4 OptimalOcclusion.pdf#page=16|MR4 OptimalOcclusion, p.16]] [[MR4 OptimalOcclusion.pdf#page=17|MR4 OptimalOcclusion, p.17]] [[MR4 OptimalOcclusion.pdf#page=18|MR4 OptimalOcclusion, p.18]] [[MR4 OptimalOcclusion.pdf#page=19|MR4 OptimalOcclusion, p.19]] [[MR4 OptimalOcclusion.pdf#page=20|MR4 OptimalOcclusion, p.20]] [[MR4 OptimalOcclusion.pdf#page=21|MR4 OptimalOcclusion, p.21]] [[MR4 OptimalOcclusion.pdf#page=22|MR4 OptimalOcclusion, p.22]] [[MR4 OptimalOcclusion.pdf#page=23|MR4 OptimalOcclusion, p.23]] [[MR4 OptimalOcclusion.pdf#page=24|MR4 OptimalOcclusion, p.24]] [[MR4 OptimalOcclusion.pdf#page=25|MR4 OptimalOcclusion, p.25]] [[MR4 OptimalOcclusion.pdf#page=26|MR4 OptimalOcclusion, p.26]] [[MR4 OptimalOcclusion.pdf#page=27|MR4 OptimalOcclusion, p.27]] [[MR4 OptimalOcclusion.pdf#page=28|MR4 OptimalOcclusion, p.28]] [[MR4 OptimalOcclusion.pdf#page=29|MR4 OptimalOcclusion, p.29]] [[MR4 OptimalOcclusion.pdf#page=30|MR4 OptimalOcclusion, p.30]] [[MR4 OptimalOcclusion.pdf#page=31|MR4 OptimalOcclusion, p.31]] [[MR4 OptimalOcclusion.pdf#page=32|MR4 OptimalOcclusion, p.32]] [[MR4 OptimalOcclusion.pdf#page=33|MR4 OptimalOcclusion, p.33]] [[MR4 OptimalOcclusion.pdf#page=34|MR4 OptimalOcclusion, p.34]] [[MR4 OptimalOcclusion.pdf#page=35|MR4 OptimalOcclusion, p.35]] [[MR4 OptimalOcclusion.pdf#page=36|MR4 OptimalOcclusion, p.36]] [[MR4 OptimalOcclusion.pdf#page=37|MR4 OptimalOcclusion, p.37]] [[MR4 OptimalOcclusion.pdf#page=38|MR4 OptimalOcclusion, p.38]] [[MR4 OptimalOcclusion.pdf#page=39|MR4 OptimalOcclusion, p.39]] [[MR4 OptimalOcclusion.pdf#page=40|MR4 OptimalOcclusion, p.40]] [[MR4 OptimalOcclusion.pdf#page=41|MR4 OptimalOcclusion, p.41]] [[MR4 OptimalOcclusion.pdf#page=42|MR4 OptimalOcclusion, p.42]] [[MR4 OptimalOcclusion.pdf#page=43|MR4 OptimalOcclusion, p.43]] [[MR4 OptimalOcclusion.pdf#page=44|MR4 OptimalOcclusion, p.44]] [[MR4 OptimalOcclusion.pdf#page=45|MR4 OptimalOcclusion, p.45]] [[MR4 OptimalOcclusion.pdf#page=46|MR4 OptimalOcclusion, p.46]]