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 casts Mounting 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 movements To simulate mandibular movements More accurate restorations are possible on these instruments (complicated &needs long time)

Arcon Articulator condylar sphere in lower member and condylar element in upper member Non arcon articulator condylar 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) Kinematic Commonly used in fixed prosthodontics

JAW RELATIONS Vertical dimension of rest (VDR) Vertical dimension of occlusion (VDO) Intero-cclusal distance (free way space)

RVD – OVD = Interocclusal space Equations VD = RVD & OVD Always RVD >OVD RVD – OVD = Interocclusal space Freeway space = 2-4mm.

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

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