CLINICAL PEDIATRIC

DENTISTRY I

Development of Occlusion

(Ch..6. Principles and Practice of PEDODONTICS by Arathi Rao, JAYPEE, 2008)

Sunday lecture 25\11\2012

1:00 pm-2:00 pm

clinic: 2:00pm- 5:00pm

Attendance sheets are signed at the beginning

of each lecture and clinical sessions.

Sunday, November 09, 2014

OTHMAN AL-AJLOUNI 1

LECTURE OUTLINE

1. INTRODUCTION:

2. PRE-DENTAL \ DENTATE PERIOD: GUM

PADS.

3. DECIDUOUS DENTITION PERIOD:

4. THE MIXED DENTITION PERIOD:

5. THE PERMANENT DENTITION PERIOD:

6. TRNSIENT MALOCCLUSION:

Prerequisite knowledge Growth & development of face and jaws both prenatal

and postnatal

Eruption of teeth timing and sequence

Morphology of teeth both primary and permanent

Terminology of key words

Masticatory movements and path of closure of the mandible

definition of terms used Deciduous dentition

mixed dentition

Permanent dentition

Predecessor

Successor

Deciduous dentition

Lecture outline

OBJECTIVE OF LECTURE YOU SHOULD BE ABLE TO ANSWER THE FOLLOWING QUESTIONS AT THE END OF THIS

LECTURE:

1. TO KNOW STAGES OF OCCLUSION DEVELPOMENT

2. TO KNOW ARCH RELATINSHIP AT BIRTH

3. TO KNOW TYPICAL FEATURES OF OCCLUSION IN PRIMARY DENTITION.

4. TRNSIENT MALOCCLUSION IN MIXED DENTIETION.

5. FEATURES OF NORMAL OCCLUSION.

At birth - gum pads Upper horseshoe - shaped

Lower U - shaped

covered with thick fibrous muco periosteum.

Contain 24 crypts of developing teeth.

Separated , tongue lies in between

Development of deciduous dentition.

Eruption of deciduous incisors. During the first year, the gum pads enlarge and arches

widen to provide space for erupting incisors.

Timing of eruption 6 month variation

premature eruption of teeth natal and neonatal teeth.

At birth Adult

. Typical features of occlusion of primary dentition

1. SPACING: Primate space present

2. TERMINAL PLANE: Distal surfaces of primary second molars in same vertical plane.

3. DEEP BITE: positive over jet and over bite

4. WIDE DENTAL ARCHES:

5. FLAT CURVE OF SPEE:

6. SHALLOW CUSPAL INTERDIGITATION:

7. VERTICAL PLACED INCISORS: Incisors are upright

8. each maxillary tooth occlude with two mandibular teeth.

Primate spacing/Anthropoid spaces

TERMINAL PLANE

1. FLUSH TERMINAL PLANE 37%

2. MESIAL STEP TERMINAL PLANE 49%

3. DISTAL STEP TERMINAL PLANE 14%

Age changes from 3 to six years. Spacing begin to appear or existing spaces increase

due to growth

occlusal attrition

incisor position become edge to edge

distal surfaces of second molar may not remain in same vertical plane

Development of occlusion

Mixed dentition stage 6-12 years:

1. FIRST TRNSITIONAL PERIOD

2. INTER TRANSIONAL PERIOD

3. SECOND TRANSTIONAL PERIOD

Development of occlusion

Mixed dentition stage 6-12 years: 1. FIRST TRNSITIONAL PERIOD: EMERGENCE OF 1ST

PERMANENT MOLARS AND EXCHANGE PRIMARY INCISORS WITH PERMANENT INCISORS.

Development of occlusion

Mixed dentition stage 6-12 years:

2. INTER TRANSIONAL PERIOD: RELATIVELY QUITE AND

NO ACTIVE TOOTH ERUPTION IS SEEN.

Development of occlusion

Mixed dentition stage 6-12 years: 3. SECOND TRANSTIONAL PERIOD: REPLACEMENT

AND ALIGNMENT OF PRIMARY MOLARS AND CANINES BY PREMOLARS AND PERMANENT CUSPIDS.

FEATURES:

1. LEEWAY SPACE OF NANCE.

2. UGLY DUCKLING STAGE.

Leeway space Difference between total mesio -distal size of primary

canine and both primary molars always larger than total size of permanent canine first premolar and second premolar.

C+D+E> 3+4+5

In maxillary (C+D+E)-(3+4+5)=0.9 mm on each side

In mandibular (C+D+E)-(3+4+5)=0.7 mm on each side

Leeway space = (C+D+E )- (3+4+5)

Lee way space

Development of occlusion

Mixed dentition stage 6-12 years: 3. SECOND TRANSTIONAL PERIOD: REPLACEMENT

AND ALIGNMENT OF PRIMARY MOLARS AND CANINES BY PREMOLARS AND PERMANENT CUSPIDS.

FEATURES:

1. LEEWAY SPACE OF NANCE.

2. UGLY DUCKLING STAGE (BROADBENT PHENOMENON).

Physiological diastema

Physiological diastema

Inclination of deciduous and permanent incisor.

7 years old 9 years old 14 years old

Changes in the axial inclination due to the eruption of the maxillary anterior

teeth (Broadbent, 1957).

ESSENTIAL FACTORS FOR A SMOOTH TRANSITION FROM PRIMARY TO PERMANENT DENTITION

1. Primate space

2. General spacing

3. Preservation of “leeway space”

4. Sequences of eruption

5. Tooth size and jaw in harmony

Early Permanent dentition stage

Features of normal OCCLUSION Skeletal bases should be ideal

Correct size and correct relationship

Occlusal features All teeth are present and in correct contact with

their immediate neighbors in the same arch with no spacing or rotations.

There is no tooth size disproportion between maxillary and mandibualr teeth.

The teeth are at correct inclination and angulation in their respective skeletal bases. Teeth of the buccal segment should be slightly mesially and lingually inclined and the teeth o f the labial segment should be slightly mesially inclined and proclined.

Each upper tooth occludes with corresponding tooth in the lower arch and one distal to it, with the exception of the upper third permanent molars.

Upper teeth lie labial or buccal to the lower teeth The lower labial segment teeth therefore, occlude with the palatal surface of the upper labial segment teeth and the buccal cusps of the lower buccal segment teeth occlude in the fossae of the upper buccal segment teeth.

Occlusal plane is slightly curved and can be considered to form a part of a sphere. The curvature in the sagittal plane is known as the Curve of Spee Curvature in the coronal plane is known as Curse of Monson.

The incisor, canine and molar relationship are class 1

In function following observations are made, On protrusion there is incisal guidance where the

incisors remain in contact with the buccal segment teeth out of occlusion.

In lateral excursions there is either canine guidance or group function in the buccal segments and there is no balancing or non working side interferences.

Occlusal features No rotations

No crowding or spacing

Correct inclinations

class I occlusion

occlusal plane has a slight curve

Curve of spee and Curve of Monson

Permanent dentition established

Permanent dentition established

No spacing No rotations

Incisor relationship

One upper tooth occlude with two lower teeth except third molars

Occlusion of Molars.

Molar relationship