Dental Anatomy: Occlusion Overview

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Questions and Answers

What characterizes balanced occlusion?

Unilateral contact in functional excursions.

Bilateral contacts in all functional excursions. (correct)

Absence of contact during functional movements.

Variable contacts in different functional positions.

What is the consequence of having no ideal occlusion?

Perfect dental alignment.

Enhanced chewing efficiency.

Improved aesthetic appearance.

Malocclusion. (correct)

Which of the following defines malocclusion?

The absence of bilateral contacts in functional excursions. (correct)

Bilateral contacts during all functional excursions.

The presence of ideal occlusion.

Symmetrical tooth alignment.

Why is bilateral contact important in functional excursions?

It ensures a balanced occlusion. Signup and view all the answers

Which option indicates that balanced occlusion has been achieved?

Consistent bilateral contacts across all functional excursions. Signup and view all the answers

Which type of terminal plane relationship is described as 'flush' or 'straight'?

Flush (straight) Signup and view all the answers

What percentage of individuals typically exhibit a Class I molar relationship?

56% Signup and view all the answers

What is the primary concern with a flush terminal plane relationship?

It correlates with a high percentage of Class II malocclusion Signup and view all the answers

Which class of molar relationship is considered a normal occlusion?

Class I Signup and view all the answers

What is the relationship between flush terminal plane and Class II malocclusion?

Flush terminal plane is associated with a high percentage of Class II Signup and view all the answers

What does ideal occlusion lack in relation to the maxillary and mandibular teeth?

The relationship achieved in maximal intercuspation. Signup and view all the answers

What is the primary characteristic of the occlusion of the maxillary and mandibular teeth in centric occlusion?

Maximal intercuspation of all teeth. Signup and view all the answers

Which statement best describes the relationship between maxillary and mandibular teeth during occlusion?

They occlude in centric occlusion at maximal intercuspation. Signup and view all the answers

In terms of occlusion, what does maximal intercuspation refer to?

The contact point where all teeth interdigitate maximally. Signup and view all the answers

Which of the following best explains why ideal occlusion is not present?

Ideal occlusion requires simultaneous alignment of all teeth during any occlusal position. Signup and view all the answers

What happens to overbite when there is a moderate or very deep bite?

It increases excessively Signup and view all the answers

In cases of class II division 1, how do the central and lateral incisors appear?

Central incisor is retroclined while lateral incisor is proclined Signup and view all the answers

What condition is indicated by a very deep bite?

Class II division 1 Signup and view all the answers

What is the relationship between overbite and overjet in a deep bite situation?

Both overbite and overjet increase Signup and view all the answers

How do moderations in bite depth affect incisor positioning?

Incisors appear crowded Signup and view all the answers

What defines a class II division 2 malocclusion?

Increased overbite with normal overjet Signup and view all the answers

How does maximal canine guidance function during dental movements?

It assists during non-functional movements only. Signup and view all the answers

In which scenario would a normal overjet be observed?

In class II division 2 malocclusion Signup and view all the answers

What does NOT occur with maximal canine guidance?

It supports functional occlusion. Signup and view all the answers

Which statement accurately reflects the relationship between canine guidance and occlusal movement?

Canine guidance primarily benefits non-functional movement. Signup and view all the answers

What defines a centric stop in dental occlusion?

The area of occlusal contact from supporting cusps Signup and view all the answers

Which cusps are identified as supporting cusps in posterior teeth?

Lingual cusps of maxillary posterior teeth and buccal cusps of mandibular posterior teeth Signup and view all the answers

In centric occlusion, the contact of which cusp tips occurs with opposing mandibular posterior teeth?

Lingual cusp tips of maxillary posterior teeth Signup and view all the answers

Which statement accurately describes the function of the cusp tip in centric stops?

The tip of a supporting cusp is also a centric stop Signup and view all the answers

Which area is NOT involved in defining a centric stop?

Contact of anterior teeth during functional excursions Signup and view all the answers

Study Notes

Dental Anatomy Study Notes

Occlusion: The act of closure, focusing on the occlusal surfaces of teeth. It's a static relationship, encompassing all factors in masticatory system development and stability, including teeth, jaws, joints, and muscles (like TMJ).

Physiology & Occlusion

Physiology focuses on tooth alignment, while occlusion details the relationship between the upper and lower arches.

Concepts of Occlusion

1-Balanced Occlusion (Ideal): Bilateral contacts during all functional movements (e.g., jaw movement to the right or left). This means equal distribution of masticatory forces on both sides. 70% of people have normal occlusion.

Inter-cuspal Position

Functional Cusps: Contacting fossae upon closure (lingual cusps for upper posterior teeth; buccal cusps for lower posterior).
Non-functional Cusps: Important, but don't make contact with opposing fossa (B.U.L.L: buccal of upper, lingual of lower).

Centric Occlusion

Maximal, bilateral, balanced contact between the cusps of the maxillary and mandibular arches.
Centric relation describes the mandibular jaw position where the condyle is furthest posterior and superior in the mandibular fossa/glenoid fossa.

Overview of Primary Occlusion

Each tooth occludes with 2 teeth of the opposing jaw, except mandibular central incisors (with upper incisors only) and maxillary second molars (with mandibular second molars only.
Rules for Maxillary and Mandibular Teeth Occlusion: Maxillary teeth occlude with the opposing teeth and the tooth distal to them, while mandibular teeth occlude with the opposing tooth and the mesial tooth to them.
Occlusion supported by eruption of first permanent molars, and interdental spacing is important for future tooth growth. The potential for crowding in permanent teeth is tied to interdental spacing in primary dentition.

Primary Molar Relationship

Terminal Plane Relationship: Predicts secondary tooth occlusion based on the primary's position.
Types of Terminal Plane Relationships:
- Flush (straight)
- Distal step
- Mesial step

Factors Influencing the Effect of Terminal Plane Relationship on Angle's Molar Relationship

Factors influencing Angle's molar relationship: Jaw growth, forward mandible growth, sufficient leeway space for molar shift (Difference in size between deciduous molars and premolars).
Leeway space is the amount of space gained by the difference in mesiodistal diameter between deciduous molars and premolars.

Permanent Occlusion

Anteroposterior Relationship: Incisors (Class I, II, III), Canines (Class I, II, III), and Molars (Angle's Class I, II, III).
Faciolingual Relationship: Premolars and Molars.

Incisal Relationship

Class I (Normal): Overjet/overbite 2-3mm
Class II (Malocclusion): Overjet/overbite greater than 2-3mm
Class III (Malocclusion): Overjet/overbite less than 2-3mm

Canine Relationship

Class I: Maxillary canine cusp tip occluding in embrasure between mandible canine and first premolar.
Class II: Maxillary canine mesial
Class III: Mandibular canine mesial
Reverse Overjet: Mandibular incisors in front of maxillary ones.
Overjet: Horizontal distance between the incisors (1-3mm normal).
Overbite: Vertical overlap of incisors (1-4mm normal).

Centric Stops Definition

The Points where opposing teeth touch in centric occlusion.
Lingual/buccal cusp tips of the maxillary/mandibular posterior teeth make contact at fossae and marginal ridges of opposing teeth
The tip of the holding cusp is a centric stop
Important in restorative dentistry to know them, 32 teeth touching yields ~138 spots.

Movements Away From Centric Occlusion (Acentric)

Lateral Movement: The working side (non-balancing side) has contact, while the non-working side has no contact.

Movements in TMJ, Tooth Guidance

Working Side: Condylar process moves downward, forward, and laterally.
Non-working Side: Condylar process moves downward, forward, and medially.
Canine Guidance: Movement of upper canine across lower teeth.
Group Guidance: Occlusion of upper premolars/canines across lower premolars/canines.
Incisal Guidance: Contact of upper anterior teeth with lower teeth during protrusive movements.

Protrusive/Retrusive/Lateral Movements

Protrusive Movement: Mandible moves anteriorly guided by incisors.
Retrusive Movement: Mandible moves posteriorly.
Lateral Movement: Mandible moves laterally.

Antagonists

Antagonist: A tooth in one jaw that articulates (contacts) with another tooth in the opposing jaw during chewing/occlusion. Most teeth have two antagonists, except mandibular incisors and maxillary third molars.
Antagonist Contacts: Each tooth typically contacts 2 antagonists in the opposite arch.
Loss of a Tooth: Adjacency tooth movement affects antagonist contact.
Mesial/Distal Drifting: Misaligns antagonist contact.

Articulation/Occlusion

Anterior teeth at a disadvantage; more aesthetic than functional.
Occlusion must be normal (natural) or artificially built, but normal/natural is preferable.

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Description

Explore the principles of occlusion in dental anatomy, focusing on the relationship between upper and lower arches. Understand concepts like balanced occlusion, inter-cuspal position, and centric occlusion for a comprehensive grasp of masticatory dynamics.