Occlusion Part(III) / orthodontic courses by Indian dental academy

OCCLUSION (PART III) INDIAN DENTAL ACADEMY

Leader in continuing dental education www.indiandentalacademy.com

www.indiandentalacademy.com

Contents

Introduction Posterior controlling factors Anterior controlling factors Understanding the controlling

factors

Vertical determinants of occlusal morphology (on cusp height)

Horizontal determinants of occlusal morphology (on ridge and groove direction)

Summary References

Introduction

The occlusal anatomy of the teeth must function in harmony with the structures controlling the movement patterns of the mandible.

To maintain harmony of the occlusal condition, the posterior teeth must pass close to but must not contact their opposing teeth during mandibular movement

Posterior controlling factors

The angle at which the condyle moves away from horizontal reference plane is referred to as the condylar guidance angle.

Two TMJ’s –posterior controlling factors

Fixed factors

Anterior controlling factors

Vertical overlap and horizontal overlap

Variable factor (altered by dental procedures)

Understanding the controlling factorsIf the criteria for optimum functional occlusion has to be fulfilled, the morphologic characteristics of each posterior tooth must be in harmony with those of its opposing tooth or teeth during all eccentric mandibular movements.

The relationship of a posterior tooth to the controlling factors influences the precise movement of that tooth.

Therefore, the significance of the anterior and condylar guidances lies in how they influence posterior tooth shape.

Occlusal surface of the posterior teeth can be affected in 2 manners

1. Height

2. Width

Factors that influence the heights of cusps and depths of fossae are the vertical determinants of the occlusal morphology

Factors that influence the direction of ridges and grooves on the occlusal surfaces are considered the horizontal determinants of the occlusal morphology www.indiandentalacademy.com

Vertical determinants of occlusal morphology (on cusp height)

a) Effect of condylar guidance b) Effect of anterior guidance

c) Effect of plane of occlusion

d) Effect of curve of Spee

e) Effect of mandibular lateral translation movement www.indiandentalacademy.com

a) Effect of condylar guidance

b) Effect of anterior guidance

It is a function of the relationship between the maxillary & mandibular anterior teeth.

Anterior guidance = Overjet X overbite

c) Effect of plane of occlusion

It is an imaginary line extending from cusp tip of mandibular canine to distobuccal cusp of lower second molar

Relationship of this plane to the angle of articular eminence influences the steepness of the cusps.

As the plane of occlusion becomes more nearly parallel to the angle of the articular eminence, the posterior cusps must be made shorter.

d) Effect of curve of Spee

3 components affecting the cusp height are:

a) Length of the radius of the curve

b) Degree of curvature of the curve of Spee

c) Orientation of curve of Speewww.indiandentalacademy.com

Length of the radius of the curve

Degree of curvature of the curve of Spee

Orientation of curve of Spee

e) Effect of mandibular lateral translation movement

Bennett movement- A bodily side shift of the mandible that occurs during lateral movements.

The degree of medial movement of orbiting condyle depends on two factors :

a.Morphology of medial wall of the fossa.

b. Inner horizontal portion of the Temporomandibular ligament (which attaches to the lateral pole of the rotating condyle)

Lateral translation movement has 3 attributes

1. Amount

2. Direction

3. Timing

Amount and Timing are dependent on medial wall of fossa and TM ligament.

Direction depends on the direction taken by the rotating condyle.

Effect of amount of lateral translation movement on cusp height

Greater the amount of lateral translation movement, shorter is the posterior cusp

Effect of the direction of lateral translation movement on cusp height

Determined by the morphology and ligamentous attachments of the TMJ undergoing rotation.

The movement occurs within a 60 degree cone whose apex is located at the axis of rotation.

Effect of timing of lateral translation movement on cusp height

Dependent on the medial wall of fossa and TM ligament.

Immediate side shift – when the lateral translation movement occurs early

Progressive side shift – if movement occurs in conjunction with an eccentric movement

Horizontal determinants of occlusal morphology

Influences the direction of ridges and grooves on the occlusal surfaces

Each centric cusp tip generates both laterotrusive and mediotrusive pathways across its opposing tooth

Each pathway represents a portion of the arc formed by the cusp rotating around the rotating condyle

Horizontal determinants of occlusal morphology (on ridge and groove

direction)a) Effect of distance from rotating condyle

b) Effect of distance from mid-Sagittal plane

c) Effect of distance from rotating condyle and from mid-Sagittal plane

d) Effect of mandibular lateral translation movement

e) Effect of inter-condylar distance www.indiandentalacademy.com

a)Effect of distance from rotating condyle

Greater the distance – wider the anglewww.indiandentalacademy.com

b) Effect of distance from mid-Sagittal plane

More the distance – wider the anglewww.indiandentalacademy.com

c) Effect of distance from rotating condyle and from mid-Sagittal plane

The combination of the two positional relationships is what determines the exact pathways of the centric cusp tips

Because of the curvature of the dental arch; as the distance of tooth from rotating condyle increases – distance from midsagittal plane decreases, but distance from rotating condyles increases FASTER than decrease in distance from midsagittal plane.

Therefore, the teeth toward the anterior region (e.g. premolars) have larger angles than posterior teeth (e.g. molars).

d) Effect of mandibular lateral translation movement

influences the directions of ridges and grooves

Movement depends on 2 factors:

1. Amount

2. Direction

Effect of amount of lateral translation movement on ridge and

groove direction

Effect of direction of lateral translation movement on ridge and

groove direction

e) Effect of inter-condylar distance

As inter condylar distance increases – distance between the condyle and the tooth increases – wider angles

(in a given arch configuration)

As inter condylar distance increases – the tooth is placed nearer the mid-sagittal plane relative to the rotating condyle-midsagittal plane distance – decrease in the angle generated

Increase in inter-condylar distance – decrease in angle between mediotrusive and laterotrusive pathways

Summary Vertical determinants of occlusal morphology (on cusp height and fossa depth)

Horizontal determinants of occlusal morphology (on ridge and groove direction)

Factor Condition Effect

Condylar guidance

Steeper Taller

Anterior guidance

More overbiteMore Overjet

Taller Shorter

Plane of occlusion

More parallel Shorter

Curve of Spee

More acute Shorter

Lateral translation

Greater movementMore superior Greater immediate shift

Shorter ShorterShorter

Factor Condition Effect

Distance from rotating condyle

Greater Wider the angle

Distance from midsagittal plane

Greater Wider the angle

Lateral translation Greater Wider the angle

Intercondylar distance

Greater Smaller the angle

References Occlusion series in BDJ, 2001;191:6-7 Okeson JP. Management of Temporomandibular Disorders and Occlusion, ed. 4th, 1998; Mosby Ash MM and Ramfjord S. Occlusion, ed. 4th, 1966; WB Saunders Company, Michigan

Santos JD. Occlusion Principles and Concepts, ed. 2nd, 1999; Ishiyaku EuroAmerica, Inc. U.S.A. Shillingburg HT. Fundamentals of Fixed Prosthodontics, ed.3rd, 1997;Quintessence

Thank you

For more details please visit www.indiandentalacademy.com

Occlusion Part(III) / orthodontic courses by Indian dental academy

Documents

Advanced Dental Occlusion - Klausz Dental Lab · Doctor Occlusion Dental occlusion doesn't have to be complex and difficult to understand. If you have the right tools and an understanding

INTRAORAL I - Everest Dentaleverestdental.com.my/pdf/Intraoral.pdf · orthodontic intraoral devices for the correction of Class II and Class III dental occlusion . Now, even your

Occlusion in CD / orthodontic courses by Indian dental academy

Dental Anatomy & Occlusion Nuggets

Orthodontic Wires 1 / orthodontic courses by Indian dental academy

Orthodontic Retreatment: Dental Trauma and Root Resorptioncdn.intechweb.org/pdfs/24351.pdf · Orthodontic Retreatment: Dental Trauma and Root Resorption 239 happen, orthodontic repositioning

Osborne Dental Orthodontic Treatments

Advanced Dental Occlusion - Klausz Dental Labklauszdentallab.com/documents/occlusion-advanced-dental-occlusion… · Advanced Dental Occlusion ... removable appliances do not function

Dental Ceramics - Seminar / orthodontic courses by Indian dental academy

Advanced Dental Occlusion - Klausz Dental Laboratories Ltd

Determinents of occlusion morphology /certified fixed orthodontic courses by Indian dental academy

Orthodontic cements /certified fixed orthodontic courses by Indian dental academy

Dental Waxes / orthodontic courses by Indian dental academy

ATLAS Occlusion Diagnosis by BruxChecker€¦ · ATLAS Occlusion Diagnosis by BruxChecker ... the occlusal plane, the dental arch and the dental morphology. The occlusion treatment

Occlusion and Dental Developments

Dental Occlusion

2016 COURSES - Dental Focus · Continuing Medical Education Program Elite EMC 2016 COURSES. 2 DENTAL FOCUS THE OCCLUSION, THE TMJ AND ORTHODONTIC TREATMENT Orthodontic Treatment Mechanics

Orthodontic Wires -Properties / orthodontic courses by Indian dental academy

Temporomandibular disorders (TMD) Occlusion and Orthodontic treatment Thor Henrikson

Dental Pulp / orthodontic courses by Indian dental academy