Midterm Flashcards
3 Requisites of Contour
Mechanical
Biological
Esthetics
Mechanical Requisites of Contour
Movements and occlusion with other teeth
Biological Requisites of Contour
Ex. Preventing over contour to decrease chances of periodontal disease
Esthetics Requisites of Contour
Most difficult. The smallest change in contour can have very noticeable effects on patients appearance
Universal Occlusal Stand
Should be adjusted to be 10 degrees inclination
Fence
Maxillary models should be oriented so that the midline is centralized onto the inscribed midline of the fence
Condylar Guides
Should be 30 Degrees
Incision guide pin
Should be 0
The Geometric (Non-Anatomical) School of articulator designs
Denied existence of condylar axes and disregarded the consular paths as influences on occlusion. Instead, claiming that the articulation of teeth guides the mandible during mastication
The Condylar (anatomical) School of Articulator Design
Adjustable condylar guides
Average value instruments
Equilateral Triangle Theory
The size of the mandible is equal to 10 cm from condyle to condyle (4 inches) and from each condylar to the incisor point
Balkwill Angle
Triangle is formed between the occlusal plane and Bonwill triangle (about 26 Degrees)
Curve of Spee
Teeth are not flat, they have a curve
The molar mastication surface lie on the same arc of a circle. The posterior continuation of which touches the most anterior point of the condyle
The location of the axis of the cylinders curvature is at
curve of spee
The level of the horizontal mid orbital plane
The steeper the path of the condyle the_______ the tooth curve would be because_______
More pronounced
Because both have the same radius
Christensen’s Phenomeneon
The space that occurs between the maxilla and mandible during protrusion
The phenomenon of a space that occurs between mandible and maxilla when anterior teeth touch and the mandible protrudes
Christensen’s Rational Articulator
The first to describe an intraoral method for obtaining a protrusive record to determine the condylar inclination
“Arrangement of teeth is NOT flat”
Monson’s Spherical Theory
You always need to find the center of rotation
“All teeth are touching the sphere plane”
Curve of Wilson
Mediolateral Curve
In the theory that occlusion should be spherical, the curvature of the cusps as projected on the FRONTAL plane expressed in both arches; the curve in the lower arch being CONCAVE and the one in the upper arch being CONVEX
Curve of Spee__________
Curve of wilson______
Spee= anteroposterior Wilson= mediolateral
Rupert Hall’s Conical Theory of Mandibular Movements
The external occipital protuberance was considered as the anatomic ratio center of the mandible (about 10 cm from the mandible)
ARCON
Articulating condyle
Universal occlusal stand relates to
Bonwills equilateral triangle
3 Requisites in contour
Mechanical
Biological
Esthetics
Occlusal Stand inclination
10 degrees
Condylar guide
30 degrees
Incisal guid pin
Zero
VDO
Vertical Dimension of occlusion
The degree of separation (distance between) the maxillae and the mandible
VDO when in MI
0
THA
Transverse horizontal axis
Where rotation occurs
Is an imaginary line connecting the centers of two condyles
The rotational movement is limited to
About 20-25 mm of incisal separation before the mandible begins to translate
Centric Relation
A spatial relationship of one bone to another; the mandible and maxilla or cranium.
Independent of tooth contacts
Condyles articulate with the thinnest avascular portion of their respective disks
Against Articulator eminences
Centric Relation arc of Closure
When the mandible is guided to CR the arc traced by the point between 2 mandibular central incisors is referred to as the arc of closure
Centric Occlusion
If the mandible is manipulated upward on the centric relation arc of closure until tooth contact occurs the mandible is now in CO
Initial Points of contact
These contact points are located on the distal inclines of mandibular teeth and the mesial inclines of the maxillary teeth
Sagittal Plane
Rotational Movement
Horizontal Plane
Straight protrusive
Lateral movements
Working slight lateral translation
Non working travels forward and medial
Frontal Plane
Straight protrusive movements. Both condyles will move downward as they slide along emmincens.
Working-rotate and move lateral and upward or lateral and downward
Non working downward and medial
VDO
Vertical dimension of occlusion
The distance between two reference pints with the teeth in MI
VDR
Vertical dimension at rest
The distance between two points with the mandible at rest
Interocclusal rest distance
VDR-VDO
Incisal guidance
Anterior teeth guided by incisal guidance
Posterior guided by artocular eminence
Functions of Anterior Teeth
Anterior Guidance Perform initial acts of mastication Speech Lip Support Esthetics
Anterior Guidance
1) Position of the incisively edge of the mandibular anterior teeth relative to the lingual surfaces of the maxillary anterior teeth
2) Changes in morphology of the lingual surfaces of maxillary anterior teeth
3) length of mandibular incisors or canines
Occlusal Schemes
Anterior Guidance
- Incisal Guidance
- Canine Guidance
Group Function
Acron articulator
Condyles connected to the lower member
Non arcon Articulator s
Condyles connected tot heir upper members
Significance of Ear Bow Transfer
1) Relates maxillary cast to the Terminal Hinge Axis
2) Orients the maxillary cast correctly in space using a third point of reference
3) Is aligned parallel to the inter pupillary line
4) Permits mounting of the maxillary cast on a semi adjustable articulator
5) The mandibular cast is mounted using a centric relation record
CR Record
Along the arc of rotation of the mandible No teeth touching Thin Soft Fast setting Stable Verifiable
Goals of Occlusal Equilibration
To improve functional and esthetic relationships between maxillary and mandibular teeth
To eliminate TMD
The shorter the slide
The more likely it is that selective grinding can be accomplished within the confines of the enamel
Selective Grinding
A procedure by which the occlusal surface of the teeth are altered to improve the overal contact pattern.
When the slide has a great horizontal component
It becomes difficult to eliminate within the conies of the enamel
Flat cusps
Mandibular Excursions
Locate tooth in the arch
Determine if it moves
Identify movement
When the earbow transfer is used which 3 things become anatomically oriented
Maxillary arch
Mandibular Arch
Condylar Axis
Requirements of Centric Relation Record
Along the arc of rotation of the mandible
No teeth touching
Fast setting
Thin
Soft
Dimensionally stable
Easily verifiable in the mouth and on the mounted casts
Occlusal Equlibration
Refers to the correction of stressful occlusal contacts through selective grinding. It involves the selective reshaping of tooth surfaces that interfere wit normal harmonious jaw function
Anterior teeth guide ______ movements of the _____ so that no _______ teeth contact during lateral or protrusive movements
Excursive
Mandible
Posterior
In maximal intercuspal position posterior teeth______
Come into contact and act as stops to minimize horizontal load on anterior teeth
In maximal intercuspal position all mandibular teeth
Should contact their maxillary opponents at the same time and with the same intensity
CO should coincide with MI
Incisal Guidance
Immediate discussion of posterior teeth takes place on mandibular protrusion
Canine Guidance
Immediate discussion of posterior teeth takes place as soon as the lateral movement begins
Group Function
The mandibular buccal working cusps travel downward, forward and lateral in contact with the lingual inclines of the maxillary buccal cusps simultaneously with the canine
Equilibration Procedures
Reduction of all contacting tooth surfaces that interfere with the terminal hinge axis closure
Selective reduction of tooth structure that interferes with lateral excursions
Elimination of all posterior tooth structure that interferes with protrusive excursions
Harmonization of the anterior guidance
Anterior Slide correction
MUDL
MUDL
Corrects anterior slide
Mesial inclines upper
Distal inclines lower
Interference of the arc of closure
Has the effect of displacing the mandible forward of the interference to reach MI
Interference of the line of Closure
Primary interferences that cause the mandible tod evictee right or left from the initial contact point to MI
If the interfering incline causes the mandible to deviate toward the cheek
BULL
BULL
If the interfering incline causes the mandible to deviate toward the cheek
Grind the buccal incline of the upper
lingual incline of the lower
or both
If the interfering incline causes the mandible to deviate toward the tongue
LUBL
LUBL
If the interfering incline causes the mandible to deviate toward the tongue
Grind the lingual incline of the upper
Buccal incline of the lower
Or both
Centric Interferences
To the arc of closure
Line of closure
Lateral Interferences (on opening)
Divided into interferecens of the working side or non working side
Non working interferences on opening
BULL
Working side interference on opening
Use LUBL to get anterior guidance preferably
Rule for eliminating protrusive interferences
DUML