1/10: Intro. Articulators and Facebows Flashcards
What are types of restorative materials for teeth?
Dental amalgam
Composite materials
Gold restorations (gold foil)
Gold castings (inlays, onlays, crowns)
Ceramics (crowns, bridges (fxed partial dentures), veneers
What are two important concerns about dental amalgam as restorative material?
Biocompatible - not generally considered problem for patients
wastewater - pollution with mercury
What are advantages to dental composite?
Aesthetics
Bonding to the tooth structure
Can be more conservative
Less expensive
Reduced mercury
What are disadvantages to dental composite?
Shrinkage
Durability
Chipping
More skill required
Need to keep area dry
Time and expense
What does bonding allow for?
The dentist to use dental composites on teeth to change shape, color or contours
What is the oldest type of filling material available?
Gold foil or direct gold
What type of material can last the lifetime of a patient?
Gold foil or direct gold
What kind of material can be placed in one visit in small cavities and will last longer than any other restorative material?
Pure gold
What are types of crowns?
Cast gold
Porcelain fused to metal
High strength ceramics
How long will PFM crowns last?
95% success rate between 5-10 years in cross-sectional study
97.5% success rate at 7 years
95.5% at 7 years assessed in private practices
What are types of tooth replacements?
Complete dentures (with implants)
Partial dentures (with implants)
Fixed bridges and single teeth (with implants)
What are some positives of high strength ceramics?
Broad range of indications
Excellent clinical performance
Accepted metal alternative
Less tooth reduction required
Thinner coping thickness
Shaded coping options offer improved esthetics
What is a mechanical device that simulates mandibular movements of condyles in their fossae?
Articulators
What are the four uses of an articulator?
Diagnosis
Treatment planning
Communicate with patients/patient education
Fabrication of prostheses/restorations
Label the components of an articulator
What kind of movements do non adjustable or “hinge” articulators allow for?
Only opening and closing movements
What are non adjustable or hinge articulators used for?
Single posterior restorations
What can a non adjustable or hinge articulators use create?
A change in the closure angle, and by doing so the final restoration will present premature contacts
What kind of articulators are used the most?
Semi-adjustable articulators
What do semi-adjustable articulators allow for?
Opening and closing
Movements as well as excursive
Lateral and protrusive movements
What are the two types of semi-adjustable articulators?
Arcon
Non arcon
What are arcon articulators?
Condyles in lower member
Condylar inclination in the upper member
What are non arcon articulators?
Condyles on upper member
Condylar inclination on the lower member
What type of articulator is our articulator?
Arcon articulator
What is the purpose of a face-bow?
Orient the maxillary cast to the rotational axis in three planes
What does using a face-bow result in?
Reproducible articulation of subsequent maxillary casts
What does the face-bow orient?
The dental cast in the same relationship to the opening axis of the articulator
What are the anatomic references of the facebow?
Mandibular condyles
Transverse horizontal axis
One other selected anterior point
What do kinematics locate?
The true transverse horizontal axis of rotation
What do arbitrary locate?
The axis by using anatomical landmarks
What does arbitrary utilize to locate?
Average measurements to approximately locate the axis of rotation
What is the transverse horizontal axis or terminal hinge axis?
Imaginary axis which passes through each of the mandibular condyles
What is the transverse horizontal axis around?
This axis that pure rotational movement of the mandible occurs
Where is the transverse horizontal axis located?
About 8mm under the soft tissues in front of the tragus (on each side of the face)
What is the bergstrom point?
A point 10mm anterior to the center of a spherical insert in the external auditory meatus and 7mm below the frankfort horizontal plane
Where does the ear-bow index to?
External auditory meatus
What does the ear bow register?
The relation of the max arch to these and a horizontal reference plane
What does the facebow orient the maxillary cast to?
A reference plane
What does the reference plane require?
3 points (2 on each side of the face and one on the anterior face)
What should the anteiror reference (aka 3rd point of reference) be?
Repeatable and reproducible
What is the orbitale of the 3rd point of reference?
The lowest point on the infra-orbital rim (spring bow)
When should you use a face-bow?
- Cusp teeth are present
- Interocclusal records are made at an increased occlusal vertical dimension
- The occlusal vertical dimension is subject to change and alteration in occlusal surfaces are necessary
