Mestra Semi-adjustable Articulator Type ARCON:

Question 1

What is an articulator?

What is it used for?

Answer 1

The articulator is an instrument used to simulate the maxillo- mandibular relation and movements of a patient in the laboratory, with the purpose of studying the occlusion and for the construction of dental prosthesis that will be used by the patient. These devices include complete dentures, partial dentures, bridges, crowns, bite plates etc

Question 2

What does Mestra semi-adjustable articulator provide?

Answer 2

• It provides a simple, fast, and precise way of reproducing the human mandible movements,, enabling the dental professional to carry out corrective and restorative dentistry tasks more easily and rapidly.
• the semi-adjustable articulator produces far more accurate results than those produced by simple hinge articulators which involve arbitrary mounting of the mandibular cast on the device and whose movements are also limited.

Question 3

Preparing the articulator:

Answer 3

• The adjustments of the articulator mentioned here below are only used to mount the casts on the articulator. However, the operator may choose to use other angulation to personalize the settings.
• To facilitate the mounting of the casts adjust the condylar guide angles at 30° and the Bennet angle at 15°. Then push back the upper part of the central lock until feel the “click” (locked position).
• Condylar guide angle should be at 30° and
• Bennet angle at 15°.
• Place the incisal guide pin in the upper arm of the articulator with its rounded tip pointing downwards so that the upper and lower arms are parallel
• The marking on the Incisal guide pin should be set to Zero

Question 4

What is a Mestra articulator? What is it used for?

Answer 4

Mestra articulator is a semi-adjustable ARCON type articulator and can be used with a face-bow to transfer the jaw registration from the patient to the articulator.

Question 5

Mounting casts on the articulator:

Q: How is it done?

Answer 5

A: with the aid of a face-bow

• Taking the bite using a bite-fork
• Face-bow oriented in position on the patient
• Face-bow transferred in the articulator
• Upper cast positioned on bite-fork registration bite

Question 6

Interocclusal registration:

What has to be done in order to set up the upper cast in the articulator?

Answer 6

To set up the maxillary (Upper) cast in the articulator, you should have a record correlating the upper and lower dental arches, according to the purpose of mounting in one of the following ways:

• Maximum Intercuspation (MI)
• Centric Relation (CR)

These records can be achieved using different kind of materials depending on the operator’s preference such as:

• Wax
• Silicones

Question 7

How is the bite registration taken?

Answer 7

Silicone bite registration material is applied on the occlusal surface of the teeth and then the patient is asked to close in the habitual closing position.

Question 8

How is the maximum intercuspation (MI) obtained during bite registration?

Answer 8

To obtain the maximum intercuspation (MI) registration, place the selected material of choice ontop of the occlusal surface of one arch of the patient’s mouth and ask him to occlude.

Question 9

How is Centric Relation records obtained during bite registration?

Answer 9

As far as obtaining the centric relation records there are several techniques that the operator may choose to apply such as:

• Peter Dowson’s technique (bilateral manipulation of the mandible)
• Lucia’s JIC technique
• James Long technique (use of plastic spacer)

Question 10

How is bite registration obtained in totally edentulous patients?

Answer 10

For totally edentulous patients the registration is made when the upper and lower wax rims are joined together in the correct interocclusal records.

Question 11

Bonwill concept:

Answer 11

Bonwill in 1864 introduced the theory of equilateral triangle in which the distance between the condylar (intercondylar) distance is 10 cm and the distance between the condyles and the incisal point is also 10 cm

Question 12

What does the occlusal pointer indicate?

Answer 12

Occlusal pointer indicates the midline of central incisors and orientation of the occlusal plane

Question 13

Mestra mounting plates:

Answer 13

• For the Mestra articulator the mounting plates are different than those of the classical mean value mounting plates. Mestra mounting plates have rail shape that permits them to slide them off the mounting stone and returned them back to the articulator to be used again for the next case.
• Therefore is very important to keep their boarder periphery totally clean and uncovered from stone so that they can be retrieved and used for the next case

Question 14

How is the possibility of reusing the mounting plates without breaking the model achieved?

Answer 14

The possibility of reusing the mounting plates without breaking the model is achieved by the use of the rail mounting plates that come with Mestra articulator.

Question 15

Maintenance and cleaning:

Answer 15

• Manufacturers recommend only warm water for the general cleaning of the articulator
• Because the articulator is a precision instrument, it should be handled, transported and stored carefully..
• Use the plastic case