Chapter 9: Articulators and face bows Flashcards
What is an articulator?
It is a mechanical instrument that stimulates mandibular movement.
It relates the lower model to the upper model in its exact position, which will have been transferred due to the face bow.
The articulator reproduces the lower teeth’s displacement concerning the upper ones. True or False
True
What does the face bow allow?
The orientation of the upper model similarly as it is related to the base of the skull
What are the 3 types of articulators?
- Not adjustable
- Semi-adjustable
- Fully adjustable
Not adjustable articulator characteristics:
- Hinge type: very inaccurate
- Fixed guidance articulators:
Opening/closing and laterality
Inaccurate because the condylar guidance cannot be adjusted
Semi-adjustable articulator characteristics:
- It admits a face bow
- It allows adjustment and individualisation
- They reproduce condylar movements in a straight line
What is the articulator that is not acceptable?
The not adjustable articulator
What is the most commonly used articulator?
The semi-adjustable articulator
Classification of condylar mechanism:
- Arcon type:
- Condylar spheres at the lower frame (same as the patient)
- Mechanical glenoid fossa attached to the upper frame
- Most semi-adjustable and fully adjustable - Non-Arcon type:
- Condylar spheres at the upper frame
- Mechanical glenoid fossa at the lower
- Lower accuracy reproducing CPI
Fully adjustable articulator characteristics:
- Kinematic face-bow –> locate the actual hinge axis
- They are adjusted with a pantograph
Requirements for an articulator:
- Accept a face bow
- The articulator must be rigid and stable and have a defined and safe position for CR in opening and closing
- Adaptable condylar mechanisms
- Adjustable incisal stem that allows changes in the VD
- Adjustable incisal table –> Customise the anterior guidance
- It should have an adjustable intercondylar distance
What are the objectives of the articulator?
- Diagnosis:
- Evaluate the occlusal status
- Mounting in CR - Planning:
- The necessity of selective occlusal grinding
- Diagnosis waxing-up
- Design - Performing:
- Manufacture of different prostheses
Indicate if the information is true or false regarding the non-adjustable articulator:
- They cannot be adjusted so they are inaccurate
- They reproduce the mandibular biodynamic properly
- They only reproduce the MI
- They are correct in opening and closing
- True
- False, they do not reproduce the mandibular biodynamic properly
- True
- They are not correct in opening and closing
Advantages and disadvantages of a non-adjustable articulator:
Advantages:
- Cheap
- Less mounting time
Disadvantages:
- Poor occlusal result
