DENTAL ARTICULATORS

• Dental articulator is a mechanical device which represents the TMJ and the jaw members to which maxillary and mandibular casts may be attached to simulate some or all jaw movements

Purposes Of An Articulator

• Hold maxillary and mandibular casts in a determined fixed relationship

• To produce Hinge, lateral and protrusive movements

Uses Of An Articulator

•To diagnose occlusion•Correct and modify artificial

restorations•To find out the relation between

natural & artificial teeth•Arrangement of artificial teeth

Requirements Of An Ideal Articulator

• Should hold cast in correct horizontal &vertical relationship

• Should open &close in hinge movement• Moving parts should move freely &non

moving parts should be rigid• Should accept face-bow• Should be made of non corrosive

material.

Limitations of articulators

• Articulators may show errors due to metal fatigue

• Articulators may not exactly simulate mandibular movements

• Articulators can not detect errors in jaw relations

Classification Of Dental Articulators

• Here we are going to discuss classification based on the ability to simulate jaw movements

*Simple articulator**Mean – value articulator***Semi-adjustable articulator**** Fully adjustable articulator

Simple Articulator

• Able to accept a single static registration. Only vertical movement is possible.

• Can be used when a tentative jaw relation is done (for diagnostic purposes)

Mean Value Articulator(Average-Value Articulator)

• Permits horizonal and vertical but not orient motions to TMJ

• The condylar path is fixed in the order of 30 degree

• Has incisal pin guide which helps to hold the articulator open at a definite position

• Suitable for patients having condylar path around 30 degree

Semi-adjustable Articulator(Hanau articulator)

• Include adjustable incisal guide table• Face-bow to relate casts to hinge

movements• Horizontal path can be registered• Lateral movement can be calculated

Hanau Articulator

Semi-adjustable articulator, holds condylar sphere in upper member and condylar element in lower member

Horizontal condylar guidance can be adjusted through protrusive movemet

Lateral movement is calculated :

L = H/8 + 12

• Mounting the castsMounting is to attach casts to

articulator*Adjust articulator*Prepare the casts*Transfer maxillary cast*Mounting of mandibular cast and

adjust horizontal condylar guidance

Fully adjustable Articulator

• Accept 3dimension movementsTo simulate mandibular movementsMore accurate restorations are

possible on these instruments (complicated &needs long time)

• Arcon Articulatorcondylar sphere in lower member

and condylar element in upper member

Non arcon articulatorcondylar sphere in upper member

and condylar element in lower member

Face- bows

• Caliper instrument used to (orient the maxillary cast to cranium)

Arbitary*conventional**Ear piece (external auditory meatus)KinematicCommonly used in fixed prosthodontics

JAW RELATIONS

• Vertical dimension of rest (VDR)

• Vertical dimension of occlusion (VDO)• Intero-cclusal distance (free way

space)

VD = RVD & OVD

RVD – OVD = Interocclusal space

Always RVD >OVD

Freeway space = 2-4mm.

Equations

• Centric relation (bone to bone) &Eccentric relation• Centric occlusion (tooth to tooth)• Condylar path• Condylar guide inclination

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