© Dr Keson B C TanBDS (Hons), MSD
DETERMINANTS OF
OCCLUSAL MORPHOLOGY
© Dr Keson B C TanBDS (Hons), MSD
DETERMINANTS OF
OCCLUSAL MORPHOLOGY
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
DETERMINANTS OF OCCLUSAL MORPHOLOGY
Occlusal Anatomy
Harmony
Controlling Structures
© Dr Keson B C TanBDS (Hons), MSD
DETERMINANTS OF OCCLUSAL MORPHOLOGY
• TMJs• Anterior Teeth
Mandibular Movement Patterns -Controlling Structures
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
• Posterior portion of mandible• Anterior portion of mandible
DETERMINANTS OF OCCLUSAL MORPHOLOGY
Influence movement of
© Dr Keson B C TanBDS (Hons), MSD
• Condylar Guidance
DETERMINANTS OF OCCLUSAL MORPHOLOGY
Posterior Controlling Factors
Anterior Controlling Factors• Anterior Guidance
© Dr Keson B C TanBDS (Hons), MSD
• Fixed factor• altered only by trauma, pathosis,
or surgery
DETERMINANTS OF OCCLUSAL MORPHOLOGY
Condylar Guidance
© Dr Keson B C TanBDS (Hons), MSD
• Steepness of lingual surfacesof Maxillary incisors
• Amount of vertical overlap• Variable factor• Altered by
• Dental procedure - orthodontia, restorations, extractions
• Pathology - caries, habits, tooth wear
DETERMINANTS OF OCCLUSAL MORPHOLOGYAnterior Guidance
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
CONTROLLING FACTORS
• Proximity of tooth to Controlling Factor
Posterior Controlling Factor (PCF)vs
Anterior Controlling Factors (ACF)
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
• Vertical • Horizontal
DETERMINANTS OF OCCLUSAL MORPHOLOGY
Controlling Factors
© Dr Keson B C TanBDS (Hons), MSD
• Cusp Height & Fossa Depth
DETERMINANTS OF OCCLUSAL MORPHOLOGY
Vertical Determinants
Horizontal Determinants• Ridge & Groove Direction
© Dr Keson B C TanBDS (Hons), MSD
VERTICAL DETERMINANTS
a. Anterior Controlling Factorsb. Posterior Controlling Factorsc. Proximity of Cusps to ACF or PCF
Cusp Length and Fossa Depth
Posterior centric cusps- Disclude in Eccentric Movements- Contacts in MI
© Dr Keson B C TanBDS (Hons), MSD
VERTICAL DETERMINANTS
1. Condylar Guidance2. Anterior Guidance3. Occlusal Plane4. Curve of Spee5. Lateral Translation Movement
© Dr Keson B C TanBDS (Hons), MSD
• Angle at which the condyle moves away from a horizontal reference plans.
• Condylar Guidance Angle of Nonworking Condyle > Straight Protrusion
• Medial wall of mandibular fossa steeper than articular eminence directly anterior to the condyle.
• = Fischer angle
DETERMINANTS OF OCCLUSAL MORPHOLOGY
Condylar Guidance Angle
© Dr Keson B C TanBDS (Hons), MSD
VERTICAL DETERMINANTS
Condition : SteeperEffect : Steeper posterior cusps
Condylar Guidance
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
VERTICAL DETERMINANTS
Condition : GreaterEffect : Taller posterior cusps
Anterior GuidanceVertical Overlap
Horizontal OverlapCondition : GreaterEffect : Shorter posterior cusps
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
VERTICAL DETERMINANTS
• Plane that passes through incisal edges of max anterior and cusps of max posterior.
• Occlusal Plane vs. Horizontal Reference Plane
Plane of Occlusion
© Dr Keson B C TanBDS (Hons), MSD
Condition : More parallel to condylar guidance
Effect : Shorter posterior cusps
VERTICAL DETERMINANTS
Plane of Occlusion
© Dr Keson B C TanBDS (Hons), MSD
• A-P Curve• Tip of Mand canine along
buccal cusp tips of mandibular posteriors
• Curvature• Orientation of curve to
horizontal reference plane
VERTICAL DETERMINANTS
Curve of Spee
© Dr Keson B C TanBDS (Hons), MSD
Condition : More acute curvature
Effect : Shorter posterior cusps
VERTICAL DETERMINANTS
Curve of Spee
© Dr Keson B C TanBDS (Hons), MSD
• Bodily sideshift of mandible• Nonworking condyle inward movement
1. Morphology of medial wall of mandibular fossa
2. Inner horizontal portion of TM ligament(attached to lateral pole of Working condyle).
VERTICAL DETERMINANTSLateral translation movement
© Dr Keson B C TanBDS (Hons), MSD
• Amount• Direction• Timing
VERTICAL DETERMINANTS
Lateral translation movement
© Dr Keson B C TanBDS (Hons), MSD
• Inner horizontal portion TM ligament• Medial wall of mandibular fossa
VERTICAL DETERMINANTS
Amount
Lateral translation movement -
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
Condition : Greater magnitudeEffect : Shorter posterior
cusps
Amount
VERTICAL DETERMINANTS
Lateral translation movement -
© Dr Keson B C TanBDS (Hons), MSD
• Working condyle - morphology & ligamentousattachments
• Superior• Inferior• Anterior• Posterior
VERTICAL DETERMINANTS
DirectionLateral translation movement -
© Dr Keson B C TanBDS (Hons), MSD
Condition : More superiorEffect : Shorter posterior
cusps
VERTICAL DETERMINANTS
Direction
Lateral translation movement -
© Dr Keson B C TanBDS (Hons), MSD
• Immediate Sideshift (ISS)• Lateral translation immediately condyle
begins to translate from fossa
• Progressive Sideshift (PSS)• In conjunction with eccentric movement
VERTICAL DETERMINANTS
Timing
Lateral translation movement -
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
Condition : Greater ISSEffect : Shorter posterior cusps
VERTICAL DETERMINANTS
TimingLateral translation movement -
If sideshift occurs late
- Cusps beyond functional range- Amount and direction - no
influence !
© Dr Keson B C TanBDS (Hons), MSD
HORIZONTAL DETERMINANTS
1. Distance from rotating condyle2. Distance from midsagittal plane3. Lateral Translation Movement4. Intercondylar distance
© Dr Keson B C TanBDS (Hons), MSD
• Ridge and groove direction• Cusp position
HORIZONTAL DETERMINANTSInfluence
Centric cusp pathways• Laterotrusive• Mediotrusive• Arcs around Working
(Rotating) condyle
© Dr Keson B C TanBDS (Hons), MSD
Condition : Greater distanceEffect : Wider angle between W and NW pathways
HORIZONTAL DETERMINANTSDistance from Working Condyle
© Dr Keson B C TanBDS (Hons), MSD
Condition : Greater distanceEffect : Wider angle between W and NW
pathways
HORIZONTAL DETERMINANTS
Distance from Mid-sagittal Plane
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
Condition : Greater ISSEffect : Wider angle between W and NW pathways
HORIZONTAL DETERMINANTSLateral translation movement -Amount
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
Condition : Greater distanceEffect : Narrower angle between W and NW
pathways
HORIZONTAL DETERMINANTSIntercondylar distance
© Dr Keson B C TanBDS (Hons), MSD
© Dr Keson B C TanBDS (Hons), MSD
Relationship between ACF and PCF
• Complete denture balanceTheory that ACF and PCF are correlated
Scientific evidence• Articular eminence angle not correlated
to any specific occlusal relationship • ACF independent of PCF• Alteration of ACF possible in
therapeutic occlusal specifications
© Dr Keson B C TanBDS (Hons), MSD
A Positive Surface Error is one which occurs when the articulator under-compensates for the mandibular movement, resulting in a positive feature existing on the occlusal surface where that feature should be smaller or non-existent.
© Dr Keson B C TanBDS (Hons), MSD
• A Negative Occlusal Surface Error is one which occurs when the articulator over-compensates for a mandibular movement.
• This results in a negative feature such as a groove or fossa that is wider than ideal or conversely a positive feature such as a ridge or cusp that is somewhat narrower than ideal.
• Such posterior teeth are allowed to disclude more freely when the mandible moves.