Development of Occlusion: Key Concepts

Development of
Occlusion
Presented by- Dr. Deeksha Bhanotia (PG-1ST Year)
Under the guidance of -Dr. Mridula Trehan (Professor & Head)
Department of Orthodontics & Dentofacial Orthopaedics

CONTENTS
 Introduction
 Static Occlusion
 Dynamic Occlusion
 Pre-dentition Period
 Primary Dentition Period
 Mixed Dentition Period-
I Transitional Period
Inter-transitional Period
II Transitional Period
 Permanent Dentition Period
 Andrew’s Six keys of Occlusion (+1)
 Canine Guided Occlusion v/s Group Function
 Conclusion

Introduction
Normal Occlusion is defined as the structural composite
fundamentally consisting of jaws and teeth, characterized by the
normal relationship of the so called occlusal inclined planes that
are individually and collectively in architectural harmony with
their basal bone and cranial anatomy, exhibit correct proximal
contacting and axial positioning and have associated with them
normal growth, development, location and correlation of all
environmental tissues and parts.
-Strang & Thompson 1940

The normal occlusion was when the upper and
lower molars were in a relationship whereby the
mesio-buccal cusp of the upper molar occluded
in the buccal grove of the lower molar and the
teeth were arranged in a smoothly curving line of
occlusion.
-Angle (1899)
Hassan et al. Review Article- Occlusion, malocclusion methods of measurements- an overview, Archives of Oro-faci

Proffit WR: Contemporary Orthodontics (Edition
The line of occlusion is a
smooth (catenary) curve passing
through the central fossa of
each upper molar and across
the cingulum of the upper
canine and incisor teeth. The
same line runs along the buccal
cusps and incisal edges of the
lower teeth, thus specifying the
occlusal as well as inter-arch
relationships once the molar
position is established.

An individual’s occlusal status is
generally described by two major
characteristics: intra-arch
relationship, the relationship of the
teeth within each arch to a smoothly
curving line of occlusion and inter-
arch relationship, the pattern of
occlusal contacts between the upper and
lower teeth.
-Proffit, 1986
Hassan et al. Review Article- Occlusion, malocclusion methods of measurements- an overview, Archives of Oro-fac

Criteria for
Normal
Occlusion-
Determining
the aims of
orthodontic
treatment
Structural
Balance
Functional
Efficiency
Aesthetic
Harmony
Jackson’s
Triad
Graber TM: Orthodontics: Principles and Practice, WB Saunders, 1988

STATIC OCCLUSION
Nelson and Ash: Wheeler’s Dental Anatomy, Physiology and Occlusion (9th Edition)

Supporting
Cusps lie in
• Occlusal
embrasure or
• Central Fossa
Guiding Cusps
contact
• Facial, lingual
embrasure or
• Groove
Occlusal contacts
Nelson and Ash: Wheeler’s Dental Anatomy, Physiology and Occlusion (9th Edition); 288-93

Most of the mandibular
supporting cusps occlude in
the occlusal embrasure
between
Same maxillary
Medial maxillary
Generalized rule:
N e l s o n a n d A s h : W h e e l e r ’ s D e n t a l A n a t o m y, P h y s i o l o g y a n d O c c l u s i o n ( 9 t h

The guiding cusps of maxillary teeth
lie in facial embrasure between
Same mandibular Distal mandibular
Generalized rule:
Exceptions:
o The mesio-buccal cusp of the maxillary 1st molar lies in mesio-buccal groove of
mandibular 1st molar.
o The disto-buccal cusp of maxillary 1st molar lies in the disto-buccal groove of
mandibular 1st molar.

Generalised Rule: most mandibular cusps lie
in the embrasure between same and mesial
maxillary tooth.
Exception:
Disto-lingual cusps of molars lie in the
lingual
groove of the maxillary molars.
The lingual cusp of mandibular 1st
premolar does not reach occlusion.
Nelson and Ash: Wheeler’s Dental Anatomy, Physiology and Occlusion (9th Editio

Nelson and Ash: Wheeler’s Dental Anatomy, Physiology and Occlusion (9th Editio

Generalised rule: Most maxillary
supporting cusps occlude in the
occlusal embrasure of same
mandibular and distal mandibular.
Exception:
The mesio-lingual cusp of maxillary 1st molar lies
in the fossa of mandibular 1st molar.
The cusp of carebelli is out of occlusion by 2mm.

due to
distal tilt of lower 1st premolar.
teeth with
single occlusal contact.

C
DYNAMIC OCCLUSION
Dr. Hoard JS: Occlusal Equilibration, The Dawson Academy Blog

Dr. Hoard JS: Occlusal Equilibration, The Dawson Academy Blog

Transverse
groove:
• Divides gums into 10 segments.
Gingival
groove:
• Separates gum pad from the palate.
Dental
groove:
• Starts at the incisive papilla, extends backwards to touch the gingival groove in
the canine region and then moves laterally to end in the molar region.
Lateral
Sulcus:
• Present between deciduous canine and 1st molar segment.
Gron AM: Prediction of tooth emergence, J Dent Res 1962: 41: 573-85

-

Relationship of Gum pads:
Anterior open bite is seen at rest with contact only in the molar region. Tongue protrudes anteriorly
through this space.
Complete overjet.
Class II pattern with the maxillary gum pad being more prominent.
Mandibular lateral sulci posterior to maxillary lateral sulci.
Mandibular functional movements are mainly vertical and to a little extent antero-posterior.
Lateral movements are absent.
A precise “bite” or jaw relationship is not yet seen. Therefore, neonatal jaw relationship cannot be used
as a diagnostic criterion for reliable prediction of subsequent occlusion in primary dentition.

Characteristics of
Primary occlusion:-
Profitt WR: Contemporary Orthodontics (Edition 5);

Normal signs of primary dentition:
Spacing is usually seen in the deciduous
dentition to accommodate larger permanent
teeth in the jaws.
Primate/Simian/ Anthropoid space: This space
is present mesial to maxillary canine and distal
to the mandibular canine. This space is utilised
in early mesial shift.
Shallow overjet and overbite.
Almost vertical inclination of anteriors.
Ovoid arch form.
Straight/ flush terminal plane relation.
Profitt WR: Contemporary Orthodontics (Edition 5)

Mesial Step: Distal surface of mandibular deciduous second
molar.
Distal Step: Distal Surface of mandibular deciduous second
molar is more distal than the distal surface of maxillary
deciduous second molar, i.e. the upper second molar
occludes with two opposite teeth.
Flush Terminal: The distal surface of the mandibular
deciduous molar is in line with the distal surface of the
maxillary deciduous molar.
Between 5 and 6 years, just before the shedding of the
deciduous incisors, there are more teeth in the jaws than at
any other time.
Profitt WR: Contemporary Orthodontics (Edition

Mixed Dentition

First transitional
Inter-transitional
Second transitional
Divided into 3
phases:

First transitional period:
Emergence of first permanent
molars.
Exchange of deciduous incisors
with permanent incisors.

Eruption of Permanent First Molars
Terminal plane relationship:
When the deciduous second molars are in a flush
terminal plane, the permanent first molar erupts
initially into a cusp-to-cusp relationship, which
later transforms into a Class I molar relation using
the primate spaces- early mesial shift.

When the deciduous second
molars are in a distal step, the
permanent first molar will erupt
into a class II relation. This
molar configuration is not self-
correcting and will cause a class
II malocclusion despite leeway
space and differential growth.

Primary second molars in
mesial step relationship lead
to a class I molar relation in
mixed dentition. This may
remain or progress to a half or
full cusp Class III with
continued mandibular growth.

Early mesial shift in arch with physiologic
spacing:
Eruptive force of the permanent molars
causes closing of any spaces between the
primary molars or primate spaces, thus
allowing molars to shift mesially.

Early mesial Shift:
Eruption of first
permanent molar
cause early mesial
shift and utilization
of primate spaces.

A distal step in
primary
dentition results
most likely in
class II occlusion
in permanent
dentition.

C
Exchange of incisors:
Incisal liability about 7.6mm in maxilla and 6mm in mandible.
Utilisation of interdental spaces present in primary dentition.
Increase in intercanine width.
Change in incisor inclination.

Gron AM Prediction of tooth emergence, J Dent Res 1962: 41: 573-85

Inter- transitional Period (1.5 years)
The teeth present are the permanent incisors and the first molar along with
the deciduous canines and molars.
1. Any asymmetry in emergence and corresponding differences in height
levels or crown lengths between the right and left side teeth are made
up.
2. Occlusal and interproximal wear of deciduous teeth.
3. Ugly duckling stage
4. Root formation
5. Resorption of roots of deciduous molars.
This phase prepares for the second transitional phase.
Profitt WR: Contemporary Orthodontics (Edition 5

Inter-Transitional Phase
Ugly duckling stage/ The Broadbent’s Phenomenon-
Around the age of 8 years, a midline diastema is commonly seen
in the upper arch, which is usually misinterpreted by the parents
as malocclusion.

Crowns of canine in young jaws impinge on
developing lateral incisor roots, thus driving the
roots medially and causing the crowns to flare
laterally.

The roots of the central incisors are also forced
together thus causing a maxillary mid-line diastema.
The period from the eruption of lateral incisor to
canine is termed as the ugly duckling stage.

With eruption of canines, the
impingement from the roots shifts
incisally thus driving the incisor crowns
medially, resulting in closure of the
diastema.

The Second Transitional Period
The following events take place:
1. Exfoliation of primary molars and canines. At around 10 years
of age, the first deciduous tooth in the posterior region, usually
the mandibular canine sheds and marks the beginning of the
second transitional period.

2.Eruption of permanent canines and premolars. These teeth
erupt after a pause of 1-2 years following incisor eruption. The
first posterior teeth to erupt are the mandibular canine and first
premolar (9-10 years) followed by maxillary premolars and
canine around 11-12 years.
Common eruption sequence is 4-5-3 in the maxilla and 3-4-5 in
the mandible.
Profitt WR: Contemporary Orthodontics (Edition 5); 86-

Second Transitional period:
Replacement of deciduous
molars and canines by
premolars and permanent
canine.
Use of leeway space
1.8 mm in maxillary arch.
3.4 mm in mandibular arch.

The dimension of
deciduous 2nd
molars is more
than that of 2nd
premolars, this
excess space is
called as E-Space.
Luciana Q.P. Fernandes a,*, Rhita C. Almeida a, Barbara N.G. de Andrade a, Felipe de Assis R. Carvalho a, Marco Antonio de O. Almeida b, Flavia R.G. Artese c Is E space similar to leeway space. Rio

Permanent
Dentition
Profitt WR: Contemporary Orthodontics (Edition 5); 86-90

Process of tooth Eruption
Tencate divided tooth eruption into the following 3
stages:
1.Pre- eruptive tooth movement: Movement of tooth
germs within the jaws before they begin to erupt.
2.Eruptive tooth movement: Tooth movement from
its position within the jaws to its functional positon.
3.Post –eruptive tooth movement: Maintaining the
position of erupted teeth in occlusion while the
jaws continue to grow.
Ten Cate’s Oral Histology: Development, Structure and Function

Tooth eruption can also be divided into:
1. Pre-emergent eruption: During the stage of crown formation, there is
very slow labial or buccal drift of the tooth follicle within the bone.
However, there is no eruptive movement. Resorption is the rate
limiting factor in pre-emergent eruption.
2. Post- emergent eruption: Once a tooth emerges into the mouth, it
erupts rapidly ( about 4mm in 14 weeks) until it approaches the
occlusal level and is subjected to forces of mastication.
This stage of relatively rapid eruption is called as the post-emergent
spurt.

Andrew’s
six keys to
Normal Occlusion
Andrews LF: Wheeler, RC An Atlas of Tooth Form (Edition 4

Key-1 Molar Inter-arch relationship
The mesio-buccal cusp of the
permanent maxillary first molar
occludes in the groove between the
mesial and middle buccal cusps of
the permanent mandibular first
molar.
The distal marginal ridge of the
maxillary first molar occludes with
the mesial marginal ridge of the
mandibular second molar.
Andrews LF: Wheeler, RC An Atlas of Tooth Form (Edition 4), 296-309

Key II: Mesio-distal Crown
Angulation
Essentially all crowns in the sample
have a positive angulation ( the
gingival portion of the long axis of
crown is more distal than the
incisal portion)

Key III: Antero-posterior Crown Inclination
Most maxillary incisors- a positive inclination
The centrals are more positive than the laterals
Mandibular incisors: slightly negative inclination.

The canines and premolars are negative and
quite similar.
The inclinations of the maxillary first and
second molars are also similar and negative,
but slightly more negative than those of the
canines and premolars.
Inclinations of the mandibular crowns are
progressively more negative from the
incisors through the second molars.

Key IV: Rotations
Absence of rotations

Key V: Tight Contacts
Contact points should abut
unless a discrepancy exists in
mesio-distal crown diameter.

Key VI:
Curve of Spee
The depth of the
curve of spee ranges
from a flat plane to
slightly concave
surface.

C
Occlusal Curvatures
This is a curved occlusal surface that makes simultaneous contact with the
major portion of the incisal and occlusal prominence of the existing teeth.
Compensating Curves
The anteroposterior and lateral curvatures in the alignment of the
occluding surfaces and incisal edges of artificial teeth which are used to
develop balanced occlusion.
Two types of curves are-
Antero-posterior curves
Lateral Curves

Curve of Spee-
Antero-posterior
curvature of the occlusal
surfaces beginning at the
tip of the lower cuspid
and following the cusp
tips of bicuspids and
molars continuing as an
arc through the condyle.

Curve of Wilson
It is the mediolateral curve that
contacts the buccal and lingual cusp
tips on each side of the arch. It results
from inward inclination of the lower
posterior teeth, making the lingual
cusps lower than the buccal cusps on
mandibular arch.

Curve of Monson
• Combination of curve of Spee and the curve of Wilson.
• Coronal and sagittal planes.
• Concave for the mandibular arch and convex for the maxillary
arch.
• In centric occlusion form a segment of a sphere of 4 inch
radius with the center of the sphere at the glabella.

Key VII: Bolton’s Analysis
Analysis deals with arch length, arch width, arch perimeter.
While calculating the total tooth material the sum of
mesiodistal diameter of the 12 maxillary teeth & the sum of
the mesiodistal diameter of the 12 mandibular teeth are
determined.
2nd Molar NOT Included.
Given by Bennet & Mc Laughin in 1993
Deepti S Fulari, Sangamesh G Fulari, Vishwal A Kagi, Jiwanasha M Agarwal, Seventh Key of Occlusion, IJCMR, Vol 3 Issue 7, 2016

In same manner the sum of 6 maxillary anterior
teeth & the sum of 6 mandibular teeth is
determined.
Deepti S Fulari, Sangamesh G Fulari,Vishwal A Kagi, Jiwanasha M Agarwal, Seventh Key of Occlusion, IJCMR,Vol 3 Issue 7, 2016

INFERENCES:-
If the ratio is more than mean value, then the
mandibular tooth material is excessive
If the ratio is less than mean value, then the
maxillary tooth material is excessive

Types of Occlusion
Group Function
Canine guided
Occlusion
Neeta Pasricha, Vinus Sidana, Satpreet Bhasin, Monika Makkar, Canine Protected Occlusion Review Article, Department of Prosthodontics, National Dental College & Hospital

Conclusion
You cannot treat dysfunction unless you understand
normal function.
-Jeffrey P. Okeson
By making a detailed study of dentition from initiation
through eruption till functional occlusion, we may be
able to obtain a clear concept of how occlusion
develops and how its development can be guided.

References
◦ Profitt WR: Contemporary Orthodontics (Edition 5)
◦ Graber TM: Orthodontics: Principles and Practice, WB Saunders, 1988
◦ Gron AM Prediction of tooth emergence, J Dent Res 1962: 41: 573-85
◦ Andrews LF: Wheeler, RC An Atlas of Tooth Form (Edition 4), 296-309
◦ Deepti S Fulari, Sangamesh G Fulari, Vishwal A Kagi, Jiwanasha M Agarwal, Seventh
Key of Occlusion, IJCMR, Vol 3 Issue 7, 2016
◦ Nelson and Ash: Wheeler’s Dental Anatomy, Physiology and Occlusion (9th Edition)

◦ Ten Cate’s Oral Histology: Development, Structure and Function
◦ Dr. Hoard JS: Occlusal Equilibration, The Dawson Academy Blog
◦ Neeta Pasricha, Vinus Sidana, Satpreet Bhasin, Monika Makkar, Canine Protected
Occlusion Review Article, Department of Prosthodontics, National Dental College &
Hospital
◦ Hassan et al. Review Article- Occlusion, malocclusion methods of measurements- an
overview, Archives of Oro-facial Sciences, 2007
◦ Luciana Q.P. Fernandes a,*, Rhita C. Almeida a, Barbara N.G. de Andrade a, Felipe de
Assis R. Carvalho a, Marco Antonio de O. Almeida b, Flavia R.G. Artese c. Is E space
similar to leeway space. Rio de Janeiro, Elsevier 2012

Development of Occlusion: Key Concepts

Development of Occlusion: Key Concepts

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