Dental Anatomy: Maxillary Premolars

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Questions and Answers

What is the role of mandibular lingual cusps in the oral cavity?

Supporting the central fossa

Guiding the tongue during speech

Shearing food during mastication (correct)

Stabilizing the mandible

What is the importance of centric stops in dental restoration?

They support the vertical dimension

They prevent drifting or passive eruption

They are areas of occlusal contact (correct)

They guide the mandible during speech

Why is it essential to reproduce the occlusal anatomy in dental restorative procedures?

To achieve esthetic dental restorations

To restore preexisting or near preexisting form (correct)

To reduce dental sensitivity

To facilitate speech

What is the Curve of Spee?

The curvature that begins at the tip of the canines and follows the buccal cusps of the posterior teeth Signup and view all the answers

What is the relationship between the Curve of Spee and the Curve of Wilson?

the Curve of Monson is a combination of the Curve of Spee and The Curve of Wilson Signup and view all the answers

What is the purpose of functional cusps in the oral cavity?

To shear food during mastication Signup and view all the answers

What is the relationship between the central developmental grooves of the posterior teeth?

They are normally aligned continuously with each other in each quadrant Signup and view all the answers

What will affect the shape of a dental restoration?

The contacts on the marginal ridge Signup and view all the answers

What happens when a tooth is restored too high?

The jaw shifts, leading to joint pain. Signup and view all the answers

Where do the lingual and buccal cusps of the maxillary teeth contact the lower teeth?

At the central groove and marginal ridges. Signup and view all the answers

What is the characteristic of functional cusps?

They are more rounded and robust. Signup and view all the answers

What are the characteristics of nonfunctional cusps?

They overlap the opposing tooth without contacting it. Signup and view all the answers

What happens when you restore a tooth that causes the jaw to shift?

Jaw or joint pain occurs. Signup and view all the answers

What is the importance of knowing the interarch relationship?

It helps in planning restorative treatment. Signup and view all the answers

What is the definition of functional cusps?

Cusps that contact opposing teeth in maximal intercuspation. Signup and view all the answers

What is the term for the condyle that stays in its fossa, rotates, and moves laterally when the mandible moves laterally?

Working condyle Signup and view all the answers

What is the average angle of the condylar path during protrusive movement?

30° with the horizontal reference plane Signup and view all the answers

What is the most important aspect of condylar guidance that affects the selection of posterior teeth with appropriate cusp height?

The inclination of the condylar path Signup and view all the answers

What type of overlap affects the surface morphology of posterior teeth?

Vertical and horizontal overlap of anterior teeth Signup and view all the answers

What type of movement requires the condyles to move in a downward and forward direction?

Protrusive movement Signup and view all the answers

What guides the mandibular movements in centric occlusion?

Maxillary teeth Signup and view all the answers

What type of occlusion is guided by maxillary canines in unworn dentition?

Canine-protected occlusion Signup and view all the answers

What occurs when tooth contact occurs where teeth should be disengaged?

Occlusal interference Signup and view all the answers

What is the benefit of knowing preoperative occlusal contacts?

To plan the restoration outline and avoid contacts on cavosurface margins Signup and view all the answers

What should be the goal of occlusal adjustment in centric relation?

To maximize distribution of occlusal stresses on the teeth Signup and view all the answers

What is the purpose of using an articulating paper during occlusal adjustment?

To check the occlusion and mark where the opposing tooth contacts the restored tooth Signup and view all the answers

What should be done if the cusp tips of teeth on adjacent teeth do not occlude as they did prior to the procedure?

Lighten the contacts over the restoration Signup and view all the answers

Why is it important to preserve centric occlusion during occlusal adjustment?

To avoid TMJ issues with the patient Signup and view all the answers

What is the benefit of knowing a patient's occlusion?

To know how to create the anatomy in the restoration, functionally and esthetically Signup and view all the answers

What is the goal of occlusal adjustment in relation to the long axis of the teeth?

To have forces of occlusion borne as much as possible by the long axis of the teeth Signup and view all the answers

What should be checked in addition to centric occlusion during occlusal adjustment?

Lateral excursives Signup and view all the answers

What is a necessary condition for occlusal stability?

Stable stops on all teeth when the condyles are in centric occlusion. Signup and view all the answers

What should occur on the nonworking side during lateral excursive movements in canine-guided occlusion?

No contact between canines. Signup and view all the answers

What is necessary for the equilibrium of the masticatory system?

Anterior guidance in harmony with functional movements of the mandible. Signup and view all the answers

What should occur in protrusive movements?

Disclusion of all posterior teeth. Signup and view all the answers

What is a requirement for lateral group function?

No contact between posterior teeth on the working side. Signup and view all the answers

What should be checked before dental restoration?

The occlusal contacts on the tooth to be prepared and the adjacent teeth. Signup and view all the answers

What is necessary for the masticatory system to be in equilibrium?

All teeth in vertical harmony with the repetitive contracted length of the closing muscles. Signup and view all the answers

What is the purpose of checking occlusal contacts?

To maintain the equilibrium of the masticatory system. Signup and view all the answers

What happens when you restore a tooth that is too high?

Jaw or joint pain may occur. Signup and view all the answers

Where do the lingual and buccal cusps of the maxillary teeth contact the lower teeth?

At the marginal ridges and central grooves. Signup and view all the answers

What is the characteristic of functional cusps?

They are more rounded and robust. Signup and view all the answers

What is the purpose of functional cusps?

To help cut, crush, and grind food. Signup and view all the answers

What happens when a tooth is restored in a way that causes the jaw to shift?

The jaw or joint may experience pain. Signup and view all the answers

What is true about nonfunctional cusps?

They are normally located at the opposing embrasure and developmental grooves. Signup and view all the answers

Why is it important to know the interarch relationship?

To ensure proper alignment of the teeth during restoration. Signup and view all the answers

What is the importance of understanding the interarch relationship in dental restoration?

It saves time in restoration placement and adjustment. Signup and view all the answers

What is the main function of mandibular lingual cusps?

To shear food during chewing Signup and view all the answers

What is the relationship between the Curve of Spee and the Curve of Wilson?

The Curve of Wilson is a combination of the Curve of Spee and another curve Signup and view all the answers

Why is it important to reproduce the occlusal anatomy in dental restorative procedures?

To restore the tooth to its preexisting or near preexisting form Signup and view all the answers

What is the purpose of centric stops?

To provide areas of occlusal contact Signup and view all the answers

What is the characteristic of functional cusps?

They are in contact with the opposing teeth in centric occlusion Signup and view all the answers

What is the purpose of the Curve of Spee?

To describe the curvature of the occlusal plane Signup and view all the answers

What is the importance of the central developmental grooves of the posterior teeth?

They are normally aligned continuously with each other in each quadrant Signup and view all the answers

What will affect the shape of a dental restoration?

The contacts on the marginal ridge Signup and view all the answers

What is the condyle called that stays in its fossa, rotates, and moves laterally when the mandible moves laterally?

Working condyle Signup and view all the answers

What is the average angle of the condylar path during protrusive movement?

30° Signup and view all the answers

What affects the surface morphology of posterior teeth?

Anterior guidance and condylar guidance Signup and view all the answers

What type of movement requires the condyles to move in a downward and forward direction?

Protrusive movement Signup and view all the answers

What guides mandibular movements in centric occlusion?

Maxillary incisors Signup and view all the answers

What type of occlusion is guided by maxillary canines in unworn dentition?

Canine-protected occlusion Signup and view all the answers

What occurs when tooth contact occurs where teeth should be disengaged?

Occlusal interference Signup and view all the answers

What is the most important aspect of condylar guidance that affects the selection of posterior teeth with appropriate cusp height?

Inclination of the condylar path Signup and view all the answers

During lateral excursive movements in canine-guided occlusion, what happens to the canines on the nonworking side?

They do not contact the opposing canine. Signup and view all the answers

What is a requirement for occlusal stability?

Stable stops on all teeth when the condyles are in centric occlusion. Signup and view all the answers

What should occur on the nonworking side during lateral excursive movements in canine-guided occlusion?

Posterior teeth should disengage on the nonworking side. Signup and view all the answers

What is a requirement for the equilibrium of the masticatory system?

Stable, comfortable TMJs even when loaded. Signup and view all the answers

What should the dentist check in addition to centric occlusion during occlusal adjustment?

Occlusal contacts on the adjacent tooth. Signup and view all the answers

What is necessary for the masticatory system to be in equilibrium?

All requirements for occlusal stability are met. Signup and view all the answers

What is a requirement for lateral group function?

Working-side posterior teeth may contact in lateral group function. Signup and view all the answers

Why is it important to check occlusal contacts?

To prevent posterior teeth from interfering with the movement. Signup and view all the answers

Why is it important to know preoperative occlusal contacts?

To avoid contacts on cavosurface margins Signup and view all the answers

What is the goal of occlusal adjustment in centric relation?

To maximize distribution of occlusal stresses Signup and view all the answers

What is the purpose of using an articulating paper during occlusal adjustment?

To check the occlusion and mark the contacting areas Signup and view all the answers

What should be done if the cusp tips of teeth on adjacent teeth do not occlude as they did prior to the procedure?

Lighten the contacts over the restoration Signup and view all the answers

Why is it important to preserve centric occlusion during occlusal adjustment?

To avoid post-op discomfort and TMJ issues Signup and view all the answers

What should be checked in addition to centric occlusion during occlusal adjustment?

Lateral excursive movements Signup and view all the answers

What is the benefit of knowing a patient's occlusion?

To save time in placement and finishing Signup and view all the answers

What is the purpose of occlusal adjustments?

To adjust the occlusion to achieve optimal function and comfort Signup and view all the answers

What is the primary role of the mandibular lingual cusps in relation to the tongue?

To keep the tongue away from the occlusal table to avoid trauma Signup and view all the answers

What is the term for the areas of occlusal contact made by functional cusps with the opposing teeth in centric occlusion?

Centric stops Signup and view all the answers

Why is it essential to reproduce the occlusal anatomy in dental restorative procedures?

To maintain the pre-existing or near pre-existing form, including relative depth and height Signup and view all the answers

What is the relationship between the central developmental grooves of the posterior teeth in each quadrant?

They are normally aligned continuously with each other Signup and view all the answers

What is the curvature that begins at the tip of the canines and follows the buccal cusps of the posterior teeth when viewed from the facial?

Curve of Spee Signup and view all the answers

What is the term for the condyle that stays in its fossa, rotates, and moves laterally when the mandible moves laterally?

Working condyle Signup and view all the answers

What is the average angle of the condylar path during protrusive movement?

30° Signup and view all the answers

How will the shape of a dental restoration be affected by contacts on the marginal ridge?

It will be affected by the depth and height of the contacts Signup and view all the answers

What is the three-dimensional curvature of the occlusal plane that is a combination of the Curve of Spee and Curve of Wilson?

Curve of Monson Signup and view all the answers

What type of overlap affects the surface morphology of posterior teeth?

Vertical overlap Signup and view all the answers

What guides the mandibular movements in centric occlusion?

Maxillary incisors Signup and view all the answers

What is the purpose of supporting the vertical dimension in relation to maxillary premolars?

To prevent drifting or passive eruption Signup and view all the answers

What occurs when tooth contact occurs where teeth should be disengaged?

Occlusal interference Signup and view all the answers

What is the purpose of preserving anterior guidance during restorative procedures?

To preserve the surface morphology of posterior teeth Signup and view all the answers

What is the movement that requires the condyles to move in a downward and forward direction?

Protrusive movement Signup and view all the answers

What is the primary purpose of anterior guidance in harmony with the border movement of the envelope of function?

To ensure noninterference of posterior teeth on the working side Signup and view all the answers

What type of occlusion is guided by maxillary canines in unworn dentition?

Canine-protected occlusion Signup and view all the answers

What is the consequence of tooth contact on the nonworking side during lateral excursive movements in canine-guided occlusion?

Interference of posterior teeth on the nonworking side Signup and view all the answers

What is necessary for the equilibrium of the masticatory system?

All six requirements for the equilibrium of the masticatory system Signup and view all the answers

What is the role of the dentist in maintaining the equilibrium of the masticatory system?

To check occlusal contacts on the tooth to be prepared and adjacent teeth Signup and view all the answers

What occurs when the condyle leaves centric relation during lateral movements?

Posterior disclusion occurs Signup and view all the answers

What is the requirement for lateral group function on the working side?

Precise harmony with anterior guidance and condylar guidance Signup and view all the answers

What is the consequence of noninterference of posterior teeth on the working side?

Lateral group function on the working side Signup and view all the answers

What is the purpose of checking occlusal contacts before dental restoration?

To ensure that the restored tooth does not disrupt the equilibrium of the masticatory system Signup and view all the answers

What is the primary function of functional cusps in the oral cavity?

To crush and grind food Signup and view all the answers

What is the relationship between the lingual and buccal cusps of maxillary teeth and the lower teeth?

They coincide with the central grooves and marginal ridges of mandibular teeth Signup and view all the answers

What happens when a tooth is restored in a way that causes the jaw to shift?

All of the above Signup and view all the answers

What is the characteristic of nonfunctional cusps?

They are located in the opposing embrasure Signup and view all the answers

What is the importance of knowing the interarch relationship in dental restoration?

It saves time in restoration placement and adjustment Signup and view all the answers

What happens when a tooth is restored too high?

All of the above Signup and view all the answers

What is the purpose of functional cusps?

To crush, grind, and tear food Signup and view all the answers

What is true about the relationship between the lingual and buccal cusps of maxillary and mandibular teeth?

They coincide with the central grooves and marginal ridges of opposing teeth Signup and view all the answers

What do knowing preoperative occlusal contacts help you to do?

plan the restoration outline and avoid contacts on cavosurface margins Signup and view all the answers

What should you do when the cusp tips of teeth on adjacent teeth do not occlude as they did prior to the procedure?

Lighten the contacts over the restoration Signup and view all the answers

What is the basic principle of occlusal adjustment in centric relation?

Forces of occlusion should be borne by the long axis of the teeth Signup and view all the answers

What is the purpose of using an articulating paper during occlusal adjustment?

To mark where the opposing tooth contacts the restored tooth Signup and view all the answers

Why is it important to preserve centric occlusion during occlusal adjustment?

To avoid post-op discomfort from high occlusion Signup and view all the answers

What is the benefit of knowing a patient's occlusion?

It helps create the anatomy in the restoration, functionally and esthetically Signup and view all the answers

What should be checked in addition to centric occlusion during occlusal adjustment?

Lateral excursive movements Signup and view all the answers

What is the goal of occlusal adjustment in relation to the long axis of the teeth?

To distribute occlusal stresses in centric relation Signup and view all the answers

Study Notes

Occlusion and Restorative Dentistry

Maxillary premolars play a crucial role in supporting vertical dimension and esthetics.
Mandibular lingual cusps are sharp and help to shear food as it passes to the functional cusps for chewing.
Centric stops refer to areas of occlusal contact that a functional (supporting) cusp makes with the opposing teeth in centric occlusion.

Occlusal Anatomy

The central developmental grooves of the posterior teeth are normally aligned continuously with each other in each quadrant.
In any dental restorative procedure, the occlusal anatomy should be reproduced to preexisting or near preexisting form, including relative depth and height.

Curve of Spee and Curve of Monson

The Curve of Spee is the curvature that begins at the tip of the canines and follows the buccal cusps of the posterior teeth when viewed from the facial.
The Curve of Monson is the three-dimensional curvature of the occlusal plane, which is a combination of the Curve of Spee and Curve of Wilson.

Interarch Relationship

The lingual and buccal cusps of the maxillary teeth contact the lower teeth in a specific relationship.
Knowing the interarch relationship is essential to avoid malocclusion and restore teeth correctly.

Functional Cusps

Functional cusps are the cusps that contact opposing teeth in their corresponding faciolingual center of a marginal ridge or fossa.
They have five key features: contact opposing teeth in maximal intercuspation, support vertical dimension, are nearer to the faciolingual center of the tooth, have an outer incline with potential for contact, and are more rounded than nonfunctional cusps.

Nonfunctional Cusps

Nonfunctional cusps are the cusps that overlap the opposing tooth without contacting it.
They are normally located in the opposing embrasure or developmental grooves.

Condyles and Mandibular Movement

The working side is the side toward which the mandible moves.
The condyle on the working side stays in its fossa, rotates, and moves laterally during lateral movement.
The protrusive inclination of the condylar path affects the selection of posterior teeth with appropriate cusp height.

Occlusal Interference and Guidance

Occlusal interference exists when tooth contact occurs where teeth should be disengaged.
Anterior guidance (vertical and horizontal overlap of anterior teeth) affects the surface morphology of posterior teeth.
Mandibular movements are guided by maxillary teeth from centric occlusion.

Occlusal Adjustments

The basic principles for occlusal adjustment include maximum distribution of occlusal stresses in centric relation and changing surface-to-surface contact to point-to-surface contact.
Once centric occlusion is established, never take teeth out of centric occlusion.

Requirements for Occlusal Stability and Equilibrium

Five requirements for occlusal stability: stable stops on all teeth, anterior guidance in harmony with the border movement, disclusion of all posterior teeth in protrusive movements, disclusion of all posterior teeth on the nonworking side, and noninterference of all posterior teeth on the working side.
Six requirements for the equilibrium of the masticatory system: stable, comfortable TMJs, anterior guidance in harmony with functional movements, noninterference of posterior teeth, equal intensity contacts in centric relation, all teeth in vertical harmony with the repetitive contracted length of the closing muscles, and all teeth in horizontal harmony with the neutral zone.

Restoring a Tooth "Too High"

Restoring a tooth that causes the jaw to shift can lead to jaw or joint pain, and the patient's bite may feel off
Tooth sensitivity can occur if a tooth is restored too high
Failure to consider the interarch relationship can lead to unhappy patients and additional restoring and adjusting time

Interarch Relationship

The lingual and buccal cusps of the maxillary teeth contact the lower teeth
The relationship between the upper and lower teeth is crucial for proper alignment and function

Functional Cusps

Functional cusps are the points on teeth that contact opposing teeth in maximal intercuspation (MI)
They support vertical dimension and are more rounded and robust than nonfunctional cusps
Functional cusps are located on the faciolingual center of a marginal ridge or fossa

Nonfunctional Cusps

Nonfunctional cusps are cusps that overlap the opposing tooth without contacting it
They are typically located in the opposing embrasure and developmental grooves

Centric Stops

Centric stops are areas of occlusal contact between functional cusps and opposing teeth in centric occlusion

Curve of Spee and Curve of Monson

The Curve of Spee is the curvature of the occlusal plane that begins at the tip of the canines and follows the buccal cusps of the posterior teeth
The Curve of Monson is the three-dimensional curvature of the occlusal plane, combining the Curve of Spee and the Curve of Wilson

Condyles and Mandibular Movement

The condyles play a crucial role in guiding the mandible during lateral and protrusive movements
The inclination of the condylar path during protrusive movement can affect the selection of posterior teeth with appropriate cusp height

Importance of Anterior Guidance

Anterior guidance, provided by the maxillary incisors and canines, affects the surface morphology of posterior teeth
Preserving anterior guidance is crucial when changing the surfaces of anterior or posterior teeth that guide the mandible in excursive movements

Five Requirements for Occlusal Stability

Stable stops on all teeth when the condyles are in centric occlusion
Anterior guidance in harmony with the border movement of the envelope of function
Disclusion of all posterior teeth in protrusive movements
Disclusion of all posterior teeth on the nonworking side in lateral movements
Noninterference of all posterior teeth on the working side, with either the lateral anterior guidance or the border movements of the condyle

Six Requirements for Equilibrium of the Masticatory System

Stable, comfortable TMJs even when loaded
Anterior guidance in harmony with functional movements of the mandible
Noninterference of posterior teeth
Equal intensity contacts in centric relation
Posterior disclusion when the condyle leaves centric relation
All teeth in vertical harmony with the repetitive contracted length of the closing muscles, and in horizontal harmony with the neutral zone

Occlusal Adjustments

The basic principles for occlusal adjustment include maximum distribution of occlusal stresses in centric relation
Forces of occlusion should be borne as much as possible by the long axis of the teeth
When there is surface-to-surface contact of flat cusps, it should be changed to a point-to-surface contact
Once centric occlusion is established, never take teeth out of centric occlusion

Restoring a Tooth "Too High"

Restoring a tooth that causes the jaw to shift can lead to jaw or joint pain, and the patient's bite may feel off
Tooth sensitivity can occur if a tooth is restored too high
Failure to consider the interarch relationship can lead to unhappy patients and additional restoring and adjusting time

Interarch Relationship

The lingual and buccal cusps of the maxillary teeth contact the lower teeth
The relationship between the upper and lower teeth is crucial for proper alignment and function

Functional Cusps

Functional cusps are the points on teeth that contact opposing teeth in maximal intercuspation (MI)
They support vertical dimension and are more rounded and robust than nonfunctional cusps
Functional cusps are located on the faciolingual center of a marginal ridge or fossa

Nonfunctional Cusps

Nonfunctional cusps are cusps that overlap the opposing tooth without contacting it
They are typically located in the opposing embrasure and developmental grooves

Centric Stops

Centric stops are areas of occlusal contact between functional cusps and opposing teeth in centric occlusion

Curve of Spee and Curve of Monson

The Curve of Spee is the curvature of the occlusal plane that begins at the tip of the canines and follows the buccal cusps of the posterior teeth
The Curve of Monson is the three-dimensional curvature of the occlusal plane, combining the Curve of Spee and the Curve of Wilson

Condyles and Mandibular Movement

The condyles play a crucial role in guiding the mandible during lateral and protrusive movements
The inclination of the condylar path during protrusive movement can affect the selection of posterior teeth with appropriate cusp height

Importance of Anterior Guidance

Anterior guidance, provided by the maxillary incisors and canines, affects the surface morphology of posterior teeth
Preserving anterior guidance is crucial when changing the surfaces of anterior or posterior teeth that guide the mandible in excursive movements

Five Requirements for Occlusal Stability

Stable stops on all teeth when the condyles are in centric occlusion
Anterior guidance in harmony with the border movement of the envelope of function
Disclusion of all posterior teeth in protrusive movements
Disclusion of all posterior teeth on the nonworking side in lateral movements
Noninterference of all posterior teeth on the working side, with either the lateral anterior guidance or the border movements of the condyle

Six Requirements for Equilibrium of the Masticatory System

Stable, comfortable TMJs even when loaded
Anterior guidance in harmony with functional movements of the mandible
Noninterference of posterior teeth
Equal intensity contacts in centric relation
Posterior disclusion when the condyle leaves centric relation
All teeth in vertical harmony with the repetitive contracted length of the closing muscles, and in horizontal harmony with the neutral zone

Occlusal Adjustments

The basic principles for occlusal adjustment include maximum distribution of occlusal stresses in centric relation
Forces of occlusion should be borne as much as possible by the long axis of the teeth
When there is surface-to-surface contact of flat cusps, it should be changed to a point-to-surface contact
Once centric occlusion is established, never take teeth out of centric occlusion

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Description

Learn about the role of maxillary premolars in dental anatomy, including their relationship with mandibular lingual cusps and their function in esthetics and food shearing.