Transcript
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
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