Management of Crowding /certified fixed orthodontic courses by Indian dental academy

Etiology and Management
of Crowding

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INDIAN DENTAL ACADEMY
Leader in continuing dental education


Aetiology can be described as the
science which deals with the causation
or origin of any disease. This can be
attributed to any branch of science.
Finding the cause is curing half the disease


The Orthodontic Equation
CAUSE
ACT AT

TIMES

ON

TISSUES

PRODUCING

RESULTS

Dockrell classification
 Heredity
 Developmental causes

of unknown origin

 Trauma
 Physical agents
 Habits
 Disease
 Malnutrition

Primary Etiological Sites
 NEUROMUSCULAR SYSTEM
 BONE
 TEETH
 SOFT PARTS

TIME
 PERIOD

DURING WHICH CAUSE
OPERATES

 AGE

AT WHICH IT IS SEEN


THE ORTHODONTIC EQUATION ELABORATED
ACT AT

CAUSE

ON

TIMES

PRODUCING

TISSUES

SOME PREDISPOSING 1.CONTINUOUS 1.NEUROMUSCULAR
OR
SOME EXCITING
TISSUE
INTERMITTENT
2.TEETH
1.HEREDITY
3.BONE AND
2.MAY ACT AT
2.DEVELOPMENTAL
CARTILAGE
DIFF. AGE
CAUSES OF UNKNOWN
4.SOFT TISSUE
LEVELS
ORIGIN
OTHER THAN
3. TRAUMA
MUSCLE
4.PHYSICAL AGENTS
5.HABITS
6.DISEASE
7.MALNUTRITION

RESULTS
1.MALFUNCTION
2.MALOCCLUSION
3.OSSEOUS
DYSPLASIA

 Dental crowding

can be defined as a
discrepancy between tooth size and jaw size
that results in misalignment of the tooth row

•

Arch length a measurement of space available in
the dental arch for alignment of teeth

 Arch length

deficiency defined as a negative
difference between the space available in the
dental arch and space required to align the teeth

 Arch length

discrepancy a difference between
the space available in the dental arch and space
required to align the teeth

ETIOLOGY OF CROWDING


Disproportion bw arch size and tooth size or arch length discrepancies



Prolonged retention of deciduous teeth



Altered path of eruption



Premature loss of deciduous teeth



Delayed eruption of permanent teeth



Presence of supernumerary teeth



Trauma



Localized abnormal size and shape of teeth



Late horizontal growth of mandible



Mesial migration of buccal segments

HEREDITY
 Child

is the product of parents who have
dissimilar
genetic
material.
Thus
conflicting traits may be inherited from
both parents resulting in abnormalities.

 Racial, ethnic

and regional inter-mixture


According to Lundstrom there exists a number of human
traits that are influenced by the genes that include the
following
• TOOTH SIZE
• ARCH DIMENSIONS
• CROWDING
• ABNORMALITIES OF TOOTH SHAPE
• ABNORMALITIES OF TOOTH NUMBER
• OVERJET
• INTERARCH VARIATIONS
• FRENUM


GENETIC INFLUENCES
MALOCCLUSION CAN BE INHERITED IN
TWO
WAYS
INHERITED DISPROPORTION BW SIZE OF THE TEETH AND
SIZE
OF THE JAWS WHICH WOULD CAUSE IMPROPER OCCLUSAL
RELATIONSHIP
INHERITED DISPROPORTION BW SIZE OR SHAPE OF UPPER
AND
LOWER JAWS WHICH WOULD CAUSE IMPROPER OCCLUSAL
RELATIONSHIPS

PRIMITIVE POPULATION : MALOCCLUSION WAS LESS FREQUENT
CHARACTERISTICS OF CIVILIZATIONS
STOCKARDS EXPERIMENTS
CHUNG ET AL : HAWAIIAN MELTING POT
COMPARISON OF MONOZYGOTIC AND DIZYGOTIC TWINS
LAUWERYNS ET AL
CORRUCINI AND CO WORKERS
HARRIS AND JOHNSON IN BOLTON BRUSH GROWTH STUDY

DEVELOPMENTAL DEFECTS OF
UNKNOWN ORIGIN
These are gross defects of rare type originating in
failure of differentiation at a critical period in
embryonic development
Congenital absence of muscles
Micrognathia
Facial clefts
Oligodontia
Anodontia

CONGENITAL DEFECTS
SEEN AT TIME OF BIRTH
GENERAL

LOCAL



ABNORMAL STATE OF MOTHER
DURING PREGNANCY



MALNUTRTION



ENDOCRINOPATHIES



INFECTITIOUS DISEASES



METABOLIC/
DISEASES

ACCIDENTS AT CHILD BIRTH





MACROGLOSSIA/ MICROGLOSSIA
CLEIDOCRANIAL DYOSTOSIS

INTRAUTERINE PRESSURE



CLEFTS OF THE FACE AND
PALATE





ABNORMALITIES OF JAW DEV.
DUE TO INTRAUTERINE
PRESSURE



NUTRITIONAL



ACCIDENTAL
TRAUMA
TO
FOETUS BY EXTERNAL FORCES

TRAUMA
PRENATAL/ BIRTH INJURIES
 HYPOPLASIA

OF THE MANDIBLE

 VOGELGESICHT
 PRESSURE

OF KNEE OR LEG

 FOETUS

HEAD
FLEXED
AGAINST THE CHEST

TIGHTLY

POSTNATAL TRAUMA
 FRACTURES OF THE JAW AND TEETH
 HABITS MAY PRODUCE MICRO TRAUMA
 TRAUMA TO THE TMJ


PHYSICAL AGENTS
 PREMATURE EXTRACTION

PRIMARY TEETH

 NATURE OF FOOD


OF

HABITS


DELETRIOUS HABITUAL PATTERNS OF MUSCLE BEHAVIOUR
OFTEN ARE ASSOCIATED WITH PERVERTED OR IMPEDED
OSSEOUS GROWTH, TOOTH MALPOSITIONS, DISTURBED
BREATHING HABITS, DIFFICULTIES IN SPEECH, UPSET
BALANCE IN FACIAL MUSCULATURE AND PHYSIOLOGICAL
PROBLEMS



THEREFORE

ONE

CANNOT

CORRECT

MALOCCLUSION

WITHOUT INVOLVMENT IN SUCH REFLEX ACTIVITIES

DISEASE



SYSTEMIC DISEASES

FEBRILE DISEASES KNOWN TO UPSET DENTITIONAL
DEVELOPMENT TIME TABLE DURING INFANCY AND EARLY
CHILDHOOD
MORE LIKELY TO AFFECT QUALITY RATHER THAN QUANTITY OF
GROWTH
MALOCCLUSION SECONDARY TO CERTAIN NEUROPATHIES AND
NEUROMUSCULAR DISORDERS
SEQUALAE OF TREATMENT OF SUCH PROBLEMS AS SCOLIOSIS
BY PROLONGED WEARING OF APPLIANCES TO IMMOBILIZE
THE SPINE



ENDOCRINE DISEASES

PRENATALLY
Manifest as hypoplasia of teeth
POSTNATALLY
Retard or hasten the direction of facial growth
Rate of ossification of bones
Time of suture closure
Time of eruption of teeth
Rate of resorption of primary teeth



LOCAL DISEASES

1)

NASOPHARYNGEAL DISEASES AND DISTURBED
RESPIRATORY FUNCTION

2)

GINGIVAL AND PERIODONTAL DISEASES

3)

TUMORS

4)

CARIES
A) PREMATURE LOSS OF PRIMARY TEETH
B) DISTURBANCES IN SEQUENCE OF ERUPTION
OF PERMANENT TEETH
C) LOSS OF PERMANENT TEETH

ETIOLOGY OF LATE LOWER
ARCH CROWDING
 MARGARET RICHARDSON


Late lower arch crowding: facial growth/ drift
( Eur J Orthod 1979:1; 219-225)



Late lower arch crowding in reln. to primary crowding
( Angle orthod 1982:52;300-312)



Role of the third molar in the cause of late lower arch
crowding (AJO-AO 1989:95; 79-83)

 Pressure

from the back of the arch
because of physiologic mesial drift, the
anterior component of the force of
occlusion on mesially inclined teeth,
mesial vectors of muscular contraction, or
the presence of a developing third molar
may cause forward movement of the
buccal teeth, with shortening of the arch
and an increase in crowding.

Pressure

from the front of the arch
may cause reduction in arch length
and depth with resultant crowding.
SELMER AND OLSEN R The normal
development of the mandibular teeth and the
crowding of the incisors as a result of growth
and function. Dent Rec 1937;57:465-77.


LATE MANDIBULAR GROWTH
 CAN LEAD TO INCREASED PRESSURE

FRONT OF THE MOUTH

IN

Growth behaviour of the human bony
facial profile as revealed by serial cephs Angle
Orthod 1952;22:78-90.

 LANDE

 BJORK

AND PALLING, HUMER FELT AND
SLAGSVOLD AND SIATOWSKI

A study of the correlation
between mandibular growth direction and
changes in incisor inclination, overjet,
overbite and crowding. Eur Orthod Soc
Trans 1975:131-40.

 LUNDSTROME


SKELETAL STRUCTURE/
COMPLEX GROWTH PATTERNS


CROWDING INCREASED DUE TO PARTICULAR
TYPE OF SKELETON/ SPECIFIC TYPE OF GROWTH
PATTERN (SAKUDA ET AL)



INCREASED LOWER ARCH CROWDING WAS SEEN
TO
BE
ASSOCIATED
WITH
INCREASED
MANDIBULAR PLANE ANGLE, LARGE OVERJET,
RETROGNATHIC FACE AND INCREASED OVERBITE
(MENG ET AL)



EXTREME DEGREES OF MANDIBULAR GROWTH
INCREASED CROWDING (BJORK)

SOFT TISSUE MATURATION
 DENTOALVEOLAR

STRUCTURES ARE
RESPONSIVE
TO
SOFT
TISSUE
PRESSURES AND ADAPT TO A
POSITION OF BALANCE OF LIPS
CHEEKS AND TONGUE

 FRANKEL /LOFFLER
 WOODSIDE

/LINDER ARONSON

PERIODONTAL FORCES


TEETH ARE JOINED TOGETHER UNDER TENSION
BY THE TRANS SEPTAL FIBRES (PICTON AND MOSS)



ANY IMBALANCE CREATED BY THE TONGUE ON
ONE SIDE AND THE CHEEK AND LIPS ON THE
OTHER ARE COUNTER ACTED BY FORCES IN THE
PDL BY ACTIVE METABOLISM (PROFITT)



CONTINUOUS FORCE ON THE MANDIBULAR
DENTITION TO MAINTAIN PROXIMAL CONTACTS IN
A STATE OF COMPRESSION. FORCE INCREASED
DURING OCCLUSAL LOADING (SOUTHARD)

TOOTH STRUCTURE
 PECK AND

PECK

 SMITH

ET AL/ PUNEKY ET AL/ GLEN ET
AL/ GILMORE AND LITTLE


OCCLUSAL FORCES
 ALTERATION

IN FUNCTION MAY
PRODUCE A DIFFERENT PATTERN OF
MASTICATORY
FORCES
OR
AN
OCCLUSION
WITH
PREMATURE
CONTACTS


CONNECTIVE TISSUE CHANGES
 BONE

LOSS AS A RESULT OF AGING
OR PERIODONTAL DISEASE MAY
ALLOW TEETH TO MOVE UNDER
PRESSURE

 THEY

LIFE

CAUSE CROWDING IN LATER

Diagnosis
 Classification


According to amount of crowding in mixed dentition
(Hotz 1980)






of crowding

First degree
Second degree
Third degree

According to etiology of malocclusion




Primary = heriditary
Secondary = acquired anomaly
Tertiary

What is supporting zone?


Second degree

Third degree

Primary crowding

Secondary crowding


Coronal and apical crowding

Odontometry
 PREDICTION OF UNERUPTED TOOTH SIZE

( MIXED DENTITION ANALYSIS LIKE
MOYERS, NANCE, BALLARD, STAHLLE AND
HIXON)

 ASSESSMENT

OF TOOTH SIZE- ARCH SIZE
COMPATABILITY WITHIN THE SAME ARCH
(NANCE, HOWES, CAREY, REEZ AND
BEAZLEY)

 ASSESSMENT

OF
TOOTH
SIZE
COMPATABILITY BW 2 ARCHES (LUNSTROM

BOLTONS TOOTH RATIO
ANALYSIS


SANIN- SAVARA TOOTH SIZE
ANALYSIS


HOWES ANALYSIS


PONTS ANALYSIS










Determination of sum of
incisors
Determination
of
measured premolar value
Determination
of
measured molar value
Determination
of
calculated premolar value
S.I x 100/ 80
Determination
of
calculated molar
S.I x 100/64


CAREYS ANALYSIS
 DETERMINATION
 DETERMINATION

OF ARCH LENGTH
OF

TOOTH

MATERIAL
 DETERMINATION

OF DISCREPANCY


MIXED DENTITION ANALYSIS
 CAN

BE DIVIDED INTO 2 CATEGORIES

THOSE IN WHICH THE SIZES OF UNERUPTED
CUSPIDS AND PREMOLARS ARE ESTIMATED FROM
MEASUREMENTS OF THE RADIOGRAPHIC IMAGE
THOSE IN WHICH THE SIZES ARE DERIVED FROM
KNOWLEDGE OF THE SIZES OF PERMANENT TEETH
ALREADY ERUPTED IN THE MOUTH

Peck and Peck analysis


Conventional method
4

mandibular incisors measured with a boleys
gauge

 Unerupted

canines and premolars are obtained
by measuring the greatest M-D crown diameter
on radiographic images

 Reduce

radiographic enlargement by using
Huckabas formula
x = y x’/ y’

 Space

required = sum of incisors + values
of canines and premolars

 Space

available measured using brass
wire from M-B cusp of first permanent
molar to opposite molar

 Amount

of discrepancy = space requiredspace available

Tweed method


relations of axial inclinations of mand
incisors and basal bone made on lateral
cephs

 FMA

is bw 21º – 29 º FMIA should be 68 º
º
 FMA ≥ 30 º FMIA 65
 FMA ≤ 20 º IMPA should not exceed 92 º

 Dist

bw the objective line and the line that
passed
through
the
actual
axial
inclinations of mand incisors was
measured with vernier calipers

 Measured

value x 2 to include both right
and left sides


Total space analysis
 Method

is divided into three areas

 Anterior
Tooth measurement = sum of mand incisors + radiographic
image of canines
 Cephalometric correction
 Soft tissue modification
 Z angle is measured
 Z angle + cephalometric correction
 Upper lip thickness
 Total chin thickness


Anterior deficit = Measured value – total space
required

 Middle

area

 Tooth

measurement = crown widths of first permanent
mandibular molars + values of premolars obtained from
radiographs

 Curve

of occlusion
right side + left side/ 2 + 0.5

 Space

available
M-B cusp of primary first molar to D-B of
permanent first molars


 Posterior

area

sum of M-D widths of 2nd and 3rd molars
which are unerupted
permanent mandibular molars were
substituted for primary second molar
third molars not visible – wheelers
measurement of molar was used

X

= y – x’/ y’

 Space

presently available + estimated
increase or prediction = space available


Littles irregularity index
 Labiolingual

displacements of the digitized
anatomic contact points of anterior teeth
measured perpendicular to the arch form
from the mesial of left canine to mesial of
right canine ( AM J ORTH 75; 68:554- 63)


Treatment modalities
BEGGS

VERTICAL LOOPS


REFINED BEGGS


HIGHLY PLACED CANINES

OPEN BITE CASES

AMOUNT OF CANINE DISTALIZATION NEEDED TO CREATE
SPACE FOR RELIEVING CROWDING


V BENDS

SINGLE LOOP

PEA
 FORCES

SHOULD BE KEPT LIGHT

 SAGITTAL,

VERTICAL
ANCHORAGE
NEEDS
IDENTIFIED

 LACE

AND
LATERAL
SHOULD
BE

BACKS AND BEND BACKS USED

 POSTERIOR

SEGMENTS
SHOULD
BE
SUPPORTED WITH HEAD GEAR/ TPA IN MAX
ANCHORAGE CASES

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