Curve Of Spee
Curve Of Wilson
Curve Of Monson
Axial Position
Prosthetics
Vilnius University
4th Semester
Paula Engels, Anne Schlickenrieder, Jule Schönewolf,Yannick
Lecavelle
Samstag, 18. März 17
Outline
Curve of Spee
• HISTORY
• DEFINITION
• FUNCTIONAL IMPORTANCE
• CORRECTION
• AGE CHANGES
• CONCLUSION
Samstag, 18. März 17
History
•
Samstag, 18. März 17
FERDINAND VON GRAF SPEE, embryologist,
German, used skull with abraded teeth to define
aline of occlusion to describe first the curve of Spee
in 1890. He was the first to describe the anatomic
relations of human teeth in sagittal plane.
Definition
Samstag, 18. März 17
•
defined as: the curvature of the mandibular occlusal
plane beginning at the tip of the lower incisors and
following the buccal cusps of the posterior teeth,
continuing to the terminal molar.
•
two dimensional and curves upward from anterior
to posterior
•
The center of the ,circle‘ is located at hight near the
Orbita (radius 65-70mm)
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Functional Importance
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•
The pull of the main muscle of mastication, the
masseter, is at a perpendicular angle with the curve
of Spee to adapt for favorable loading of force on
the teeth.
•
the bending of the curve of spee enables the
masticatory muscels to adapt functions of
adduction, as well as protraction, retraction, and
lateral tensile components. - A straightening of the
chewing curve ( orthodontic reasons), which will
cause a straight curve, would totally destroy the
masticatory system, functional equilibrium and image
design/shaping
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•
It is of importance to orthodontists as it may
contribute to an increased overbite
•
A flat or mild curve of Spee was essential to an ideal
occlusion
Correction
•
Correction of exaggerated curve of Spee can be
achieved by the following tooth movements:
•
•
•
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Extrusion of molars
Intrusion of incisors
Combination of both movements
Age Changes
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•
•
may get altered physiologically with age
•
if the curve of Spee is not maintained in these
dentitions during full mouth rehabilitation, it may
lead to interferences along the mandibular
movements
significant change in the curve of Spee and decrease
in posterior disclusion during mandibular
protrusion.
Conclusion
•
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CURVE OF SPEE is important for
•
•
•
Efficient masticatory system
Have ideal occlusion
In orthodontics diagnostic and treatment plan
Outline
Curve of Wilson
• HISTORY
• DEFINITION
• FUNCTIONAL IMPORTANCE
Samstag, 18. März 17
History
•
Samstag, 18. März 17
Named after Dr. George H. Wilson, who first
described the curve in 1911
Definition
•
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The curve, viewed from the front, that contacts the
buccal and lingual cusps of the molars, being lower
in the middle due to the lingual inclination of the
long axes of the mandibular molars.
•
Crowns of mandibular posterior teeth must incline
to lingual, while crowns of maxillary posterior teeth
must incline toward buccal
•
Curve becomes deeper posteriorly, so that molars
inclination is greater than that of premolars
➔ because of this curve & associated tooth inclinations, buccal cusps
of mandibular molars & lingual cusps of maxillary molars usually
appear to be longer
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Functional Importance
•
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Purpose of this arc in occlusal curvature is to
complement paths of condyles during movements of
mandible
•
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Curve of wilson helps in two ways
•
a. Teeth are aligned parallel to the direction of
medial pterygoid for optimum resistance to
masticatory forces.
•
b. The elevated buccal cusps prevent food from
going past the occlusal table.
•
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The curve of Monson is obtained by extending the
curve of Spee & Curve of wilson to all cusps &
incisal edges.
Outline
Sphere Of Monson
• HISTORY
• DEFINITION
• FUNCTIONAL IMPORTANCE
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History
•
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Proposed by Dr. George S. Monson in 1920.
Definition
•
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An ideal curve of occlusion in which each cusp and
incisal edge touches the surface of an imaginary
sphere 8 inches in diameter.
Samstag, 18. März 17
•
•
Compensating Occlusal Curvature
•
This curvature is in form of a portion of a ball, or
sphere
•
This curvature is concave for mandibular arch &
convex for the maxillary arch
Three dimensional curvature of the occlusal plane,
which is the combination of the Curve of Spee and
the Curve of Wilson
AXIAL POSITION
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•
•
Inclination of a tooth from a vertical axis
•
These inclinations are necessary for propper
occlusal & incisal function of teeth
•
As these axial positions are described, it should be
of value to relate them to individual tooth‘s
functions, as well as its inclination relative to Curves
of Spee and Wilson
Normally described in mesio-distal & facio-lingual
directions
COMPARISON
• What is the difference between Curve of
Spee and the Curve of Wilson?
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Curve of Spee: Anteroposterior curvature of the
incisal&occlusal surface
•
Curve of Wilson: Bucco-Lingual Curvature. For
mastication. Clinically, it relates to the anterior
overbite: the deeper the curve, the deeper the
overbite
Samstag, 18. März 17
Questions ??
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Sources
•
•
Samstag, 18. März 17
picture Wilson: http://www.ptcdental.com/dentaldictionary/c/curve-of-wilson/
picture Spee:http://www.ptcdental.com/de/dentaldictionary/c/curve-of-spee/