BALANCED OCCLUSION/

ARTICULATION

Any contact between the incising / masticating surfaces of maxillary & mandibular teeth when they are in contact. It is a static position

HANAU used the term Articulation to define the contacting of teeth as the mandible moved to & fro in centric relation or eccentric relation. This is dynamic

Helpful for Stability & retention

Occlusion

Teeth are retained by PDL, when they are lost – occlusion & proprioception are lost

Teeth receive individual pressures & can move independently

Malocclusion of natural teeth affects individual teeth, but improper occlusion in dentures will effect the stability

Incising with natural teeth does not affect posterior teeth, while in dentures it causes instability

Bilateral balance is rarely seen in natural dentition

Differences between natural & artificial teeth

Balanced Non-Balanced

Centric Neutrocentric – centralization of occlusion

- pitch, position, number

Eccentric - Lateral & Protrusive

Organic – muscle & joint without

tooth function

Monoplane

Lingualized

Different theories of Occlusion

Neutrocentric Concept

Plane should be flat & parallel to ridge

Forces on denture should be concentrated over 1st molar region

1. Smaller the area of occ. surf., lesser is the amt of occ load transmitted to supp. struct.

2. Vert. force on tilted occ surf will produce non vert force on CD

3. Vert force acting on a tilted tissue support will produce a non vert force on CD base

4. Vert force on CD base lying over the resilient tissues will produce lever forces on CD

5. Vert force acting outside the ridge crest will produce tipping of CD

Sear’s axioms of CD Occlusion

Stability of CD & its occlusion when the mandible is in both centric & eccentric relations

Balanced occlusal contacts during all eccentric movements

Unlocking the cusps mesiodistally so that CD settle when there is ridge resorption

The cuspal ht shd be reduced to control the horizontal forces

Functional lever balance shd be obtained by vert tooth to ridge crest

Ideal requirements of CD occlusion

Cont’d

Cutting, penetrating & shearing efficiency of the occlusal surface equivalent to that of natural dentition

Incisal clearance during posterior functions like chewing

Minimal area of contact to reduce pressure while crushing food

Sharp ridges, cusps & sluiceways to increase masticatory efficiency

Ideal requirements of CD occlusion

Sharp units for improved incising efficiency They should not contact during mastication, but

only during protrusion Shallow incisal guidance Increased horizontal overlap to avoid

interference during settling

Requirements of Incising units

Cusps for good cutting & grinding efficiency Smaller buccolingual width to decrease the

occlusal load transferred to the tissues Group function at the end of chewing cycle in

eccentric positions Occlusal load should be directed to mean

foundation plane of ridge

Requirements of Working units

The second molars should be in contact during protrusive action

They should have contact along with the working side at the end of the chewing cycle

Smooth gliding contacts should be available for uninterfered lateral & protrusive movements

Requirements of Balancing units

The simultaneous contacting of the maxillary & mandibular teeth

on the right & left & in the posterior & anterior occlusal areas

in centric & eccentric positions, developed to lessen or limit tipping or rotating of

the denture bases in relation to the supporting structures

BALANCED ARTICULATION

Working side Non-Working side

Gysi – 1914 – arranging 33o anatomic teeth to increase stability

French – 1954 – lowering the occlusal plane to BO

Sear – posterior balancing ramps in nonanat. teeth

Concepts proposed to attain Balanced Occlusion

Pleasure – posterior reverse lateral curve to increase stability

Frush – arrange teeth in one-dimensional contact relationship, which should be reshaped during try-in to obtain BO

Concepts proposed to attain Balanced Occlusion

Hanau’s Quint – nine factors Horizontal condylar inclination Compensating curve Protrusive incisal guidance Plane of oreintation Buccolingual inclination of tooth

axis Sagittal condylar pathway Sagittal incisal guidance Tooth alignment Relative cusp height

Concepts proposed to attain Balanced Occlusion

1. Condylar guidance

2. Incisal guidance

3. Compensating curves

4. Relative cusp height

5. Plane of orientation of occlusal plane

Hanau’s Quint

Hanau’s Quint

Trapozzano – Triad of Occlusion No plane of occlusion & compensating curves

Concepts proposed to attain Balanced Occlusion

Boucher – orientation of occlusal plane, incisal guidance& condylar guidance

Angulation of cusp is more important than the height of cusp

Compensating curve enables one to increase the ht of cusp without changing form of teeth

Concepts proposed to attain Balanced Occlusion

Lott –related to posterior separation Greater the angle of condylar path – greater the

posterior separation Greater the angle of overbite – greater the separation

in anterior & posterior region Greater the separation of posterior teeth – greater /

higher must be the compensating curve Posterior separation beyond the balancing ability of

compensating curve can be balanced by introduction of the plane of orientation

Greater the separation of teeth – greater must be height of cusps

Concepts proposed to attain Balanced Occlusion

Lott’ s Concept

Lott’ s Concept

Levin’s – Quad (omitted plane of occlusion) Condylar guidance is fixed & is recorded from patient.

Balancing CG will include Bennett movt of working condyle. This may/ may not affect lateral balance

Incisal guidance is usually obtained from patient’s esthetics & phonetic requirements. It can be modified (decreased for flat ridges)

Compensating curve is most important for BO Cusp teeth have inclines necessary for BO

Concepts proposed to attain Balanced Occlusion

Levin’s – Quad

Incisal guidance Steeper – more jaw separation If overjet increased - IG is reduced If overbite increased - IG increases

Factors influencing Balanced Occlusion

Inclination of condylar path Cannot be modified

Factors influencing Balanced Occlusion

Plane of Occlusion / occlusal plane Anteriorly by ht of lower canine Posteriorly by retromolar pad Parallel to ala-tragus line/ Camper’s line Tilting it beyond 10 is not advisable

Factors influencing Balanced Occlusion

Compensating curve Determined by inclination of posterior teeth

& their vertical relationship to occlusal plane

Factors influencing Balanced Occlusion

Curve of spee

Curve of wilson

Compensating curve

Cuspal angulation

Factors influencing Balanced Occlusion

Factors influencing Balanced Occlusion

Teeth arrangement