10.Pathological migration.ppt

TOOTH MOBILITY
&
PATHOLOGICAL MIGRATION

DEFINITION
 Pathologic migration refers to tooth displacement
that results when the balance among the factors
that maintain physiologic tooth position is
disturbed by periodontal disease (Carranza).
 Pathologic migration is relatively common and
may be an early sign of disease, or it may occur
in association with gingival inflammation and
pocket formation as the disease progresses.

 Pathologic migration occurs most frequently in the
anterior region, but posterior teeth may also be
affected.
 The teeth may move in any direction, and the migration
is usually accompanied by mobility and rotation.
 Pathologic migration in the occlusal or incisal direction
is termed extrusion.

Pathogenesis
 Two major factors play a role in maintaining the
normal position of the teeth:
-The health and normal height of the periodontium.
-The forces exerted on the teeth which includes the forces of
occlusion and pressure from the lips, cheeks, and tongue.

 Factors that are important in relation to the forces of
occlusion include;
(1)Tooth morphologic features and cuspal inclination.
(2) The presence of a full complement of teeth.
(3) Physiologic tendency toward mesial migration.
(4) The nature and location of contact point relationships.
(5) Proximal, incisal, and occlusal attrition
(6) The axial inclination of the teeth.

 Alterations in any of these factors start an
interrelated sequence of changes in the
environment of a single tooth or group of teeth
that results in pathologic migration.
 Thus, pathologic migration occurs under
conditions that weaken the periodontal support,
increase or modify the forces exerted on the
teeth or both .

Changes in the Forces Exerted on the Teeth
 Changes in the magnitude, direction, or frequency of the forces
exerted on the teeth can induce pathologic migration of a tooth
or group of teeth.
 These forces do not have to be abnormal to cause migration if
the periodontium is sufficiently weakened.
 Changes in the forces may result from unreplaced missing teeth,
failure to replace first molars, or other causes.

Posterior bite collapse PBC
(Failure to Replace First Molars)
 It is a pattern of unfavorable occlusal changes that occur most
frequently after 1st molar teeth are lost and not replaced.
 The pattern of changes that may follow failure to replace
missing first molars is characteristic. In extreme cases it consists
of the following:
1. The second and third molars tilt, resulting in a decrease in vertical
dimension.
2. The premolars move distally, and the mandibular incisors tilt or
drift lingually. While drifting distally, the mandibular premolars
lose their intercuspating relationship with the maxillary teeth and
may tilt distally.
3. Anterior overbite is increased. The mandibular incisors strike the
maxillary incisors near the gingiva or traumatize the gingiva.

4. The maxillary incisors
are pushed labially and
laterally .
5.The anterior teeth
extrude because the
incisal apposition has
largely disappeared.
6. Diastemata are created
by the separation of the
anterior teeth .

Anterior component of force
 During occlusal function , a portion of occlusal force is
projected anteriorly and has been termed the anterior
component of force (ACF) .
 ACF causes axial inclination of the posterior teeth during
occlusal loading.
 This tipping force is transmitted through interproximal contacts
and doesnot progress beyond open contacts.
 It has been hypothesized that without harmonious arch form
and proper proximal contacts, ACF is not resisted and
malalignment of teeth can result.

Protrusive pattern of mastication
 Yaffe etal (1992) using sagital tracings of
mastication studied a group of 27 patients with
a protrusive pattern of function and considered
as an etiologic factor for anterior PTM.

Shortened dental arches
 SDA: was defined as a dentition where most
posterior teeth are missing , resulting in loss of
molar support and function.
 Witter etal 2001 studied migration of teeth in
patients with SDA and stated that spacing found
in SDA patients is probably related to the flaring
in patients with PBC.

Weakened Periodontal Support
 The inflammatory destruction of the periodontium in
periodontitis creates an imbalance between the forces
maintaining the tooth in position and the occlusal and muscular
forces the tooth ordinarily needs to bear.
 The tooth with weakened support is unable to maintain its
normal position in the arch and moves away from the opposing
force unless it is restrained by proximal contact.
 The force that moves the weakly supported tooth may be created
by factors such as occlusal contacts or pressure from the tongue.
 The force itself is not necessarily abnormal. Forces that are
acceptable to an intact periodontium become injurious when
periodontal support is reduced, as in the tooth with abnormal
proximal contacts.

Abnormal proximal contacts (Arch integrity)
 Abnormally located proximal contacts convert the normal
anterior component of force to a wedging force that moves the
tooth occlusally or incisal1y.
 The wedging force, which can be withstood by the intact
periodontium, causes the tooth to extrude when the periodontal
support is weakened by disease.
 As its position changes, the tooth is subjected to abnormal occlusal forces,
which aggravate the periodontal destruction and the tooth migration.
 Pathologic migration may continue after a tooth no longer contacts its
antagonist. Pressures from the tongue, the food bolus during
mastication, and proliferating granulation tissue provide the
force.

Drift (unreplaced missing teeth)
 Drifting of teeth into the spaces created by unreplaced missing
teeth often occurs. Drifting differs from pathologic migration in
that it does not result from destruction of the periodontal
tissues.
 However, it usually creates conditions that lead to periodontal
disease, and thus the initial tooth movement is aggravated by loss
of periodontal support.
 Drifting generally occurs in a mesial direction, combined with
tilting or extrusion beyond the occlusal plane. The premolars
frequently drift distally.
 Although drifting is a common sequela when missing teeth are
not replaced, it does not always occur.

Calculus and bone loss on the mesial surface
of a canine that has drifted distally.
Maxillary first molar tilted and extruded into
the space created by a missing mandibular
tooth.

Other Causes
 Trauma from occlusion may cause a shift in tooth position either by
itself or in combination with inflammatory periodontal disease.
The direction of movement depends on the occlusal force.
 Class II malocclusion.
 Pressure from the tongue may cause drifting of the teeth in the
absence of periodontal disease or may contribute to pathologic
migration of teeth with reduced periodontal support.
 Proffit has stated that the forces of tongue, lips and cheeks
together with the forces of periodontal tissues are most
important factors that determine tooth position.

 pressure from the granulation tissue of periodontal pockets has been
mentioned as contributing to pathologic migration.(Hirschfeld
1933).
 The teeth may return to their original positions after the pockets
are eliminated, but if more destruction has occurred on one side
of a tooth than the other, the healing tissues tend to pull in the
direction of the lesser destruction.
 Sutton 1985 proposed a theory that hydrodynamic forces with in
the blood vessels and inflammed tissues in the periodontal
pocket may account for abnormal tooth migration.

 Oral habits that have been associated with PTM
include lip and tongue habits , finger nail biting ,
thumb sucking , pipe smoking , bruxism and
playing wind instruments.

Bruxism
 Bruxism forces are known to damage the dental attachment
apparatus and results in abnormal occlusal forces that are
frequent and are long duration.
 Bruxism in some patients can act as an unfavorable orthodontic
force to cause PTM.
 Bruxism as an etiologic factor for PTM doesnot seem to be
evidence based.
 In a review of literature on the effects of bruxism , no mention
was made of a connection between bruxism and tooth
migration.( Glaros. A etal 1977).
 Martinez etal 1997 did not find any correlation of PTM and
bruxism.

Treatment
 Treatment of severe pathological tooth
migration involves orthodontic therapy that is
preceded by non-surgical and surigical
periodontal therapy and prosthodontic
treatment (DUNCUN .W 1997).

 Correction of PTM can be divided into four
categories:
 Extraction and replacement of migrated teeth
when migration is very severe.
 Spontaneous correction of the early stages of
PTM following periodontal therapy.
 Limited or adjunctive orthodontic therapy.
 Conventional orthodontic treatment.

 PTM is usually based on an inter disciplinary approach.
Selecting a method to manage PTM include :
 Patient compliance and co-operation.
 Motivation to keep natural teeth.
 Skeletal factors
 Economic factors
 Availability of treatment.
 systemic health.
 Acceptance of surgical periodontal treatment.

Preventing pathological tooth
migration
 Control of periodontal disease offers perhaps the single most
effective method to prevent PTM.
 Drug induced gingival overgrowth which can cause PTM is to
some degree controlable (Kantaric.A Jp 1999).
 Treatment of occlusal factors and habits associated with tooth
migration offers another approach for prevention.
 Early detection of PTM also appears to be important in
prevention since early stage PTM is reversible with periodontal
treatment only.

Tooth Mobility
Introduction
 “Mouth is the mouthpiece of mind”. For the
power of speech and beautiful smile, healthy
gums and teeth are essential. Mobile teeth are
concerned not only for the patient, but also to
the dentist, because it is the critical stage where
the tooth lies between two “S” i.e. to be saved or
sacrificed.

Forces on teeth
 Normal or physiologic forces:
Teeth and their supporting structures are subjected to severe occlusal forces
of up to 50 mg during mastication. The presence of tissue fluids and
arrangement of PDL fibers are such that these intermittent heavy forces can
be properly accommodated without tissue destruction. These forces are
transmitted through PDL fibers to the alveolar bone proper.
 Orthodontic force:
Schwartz hypothesized that the PDL space is a continuous hydrostatic
system, and forces applied to this environment by means of mastication or
orthodontic appliances create a hydrostatic pressure that would be, in
accordance with Pascal's law, transmitted equally to all regions of the PDL.
On the "pressure" side, cell replication is said to decrease as a result of
vascular constriction, causing bone resorption. On the "tension" side, cell
replication is said to increase because of the stimulation afforded by the
stretching of the fibre bundles of the periodontal ligament (PDL), thus
causing bone deposition. In terms of fibre content, the PDL on the
"pressure" side is said to display disorganization and diminution of fibre
production, while on the "tension" side, fibre production is said to be
stimulated.

 Jiggling pathologic forces:
Forces applied to a tooth during function and
parafunction may exceed the adaptive capacity. These
jiggling forces may move a tooth in a faciolingual,
mesiodistal, or vertical direction, along the X, Y or Z
axis. As a result of pressure being exerted in all
direction, the entire periodontal ligament behaves as it
is subjected to pressure only. A force that exceeds the
tooth’s adaptive capacity leads to the lesion of trauma
from occlusion.

 All teeth have a slight degree of physiologic
mobility, which varies for different teeth and at
different times of the day.
 Mobility is greatest on arising in the morning
and progressively decreases. The increased
mobility in the morning is attributed to slight
extrusion of the tooth because of limited
occlusal contact during sleep.

 During the waking hours, mobility is reduced by
chewing and swallowing forces, which intrude the teeth
in the sockets.
 These 24-hour variations are less marked in persons
with a healthy periodontium than in those with occlusal
habits such as bruxism and clenching.
 Single-rooted teeth have more mobility than
multirooted teeth. Incisors have the most mobility.
Mobility is principally in a horizontal direction,
although some axial mobility occurs, but to a much
lesser degree.

 Tooth mobility occurs in the following two stages
(Muhlemann 1967):
 In the initial, or intra socket, stage the tooth moves
within the confines of the periodontal ligament (PDL).
This is associated with viscoelastic distortion of the
PDL and redistribution of the periodontal fluids,
interbundle content, and fibers.
 This initial movement occurs with forces of about 100
g and is about 0.05 to 0.10 mm (50-100 mm).

 The secondary stage occurs gradually and entails
elastic deformation of the alveolar bone in
response to increased horizontal forces.
 When a force of 500 g is applied to the crown,
the resulting displacement is about 100 to 200
micromt for incisors, 50 to 90 micromt for
canines, 8 to 10 micromt for premolars, and 40
to 80 micromt for molars.

 When a force such as that applied to teeth in
occlusion is discontinued, the teeth return to
their original position in two stages:
 An immediate, springlike elastic recoil and
 A slow, asymptomatic recovery movement. The
recovery movement is pulsating and is
apparently associated with the normal pulsation
of the periodontal vessels, which occurs in
synchrony with the cardiac cycle (periodontal
pulse).

 Tooth mobility is an important feature of periodontal
disease. This is evidenced by the large number of
devices and method of tooth mobility assessment that
have been developed and tested.
 Tooth mobility has been considered and investigated as
an indirect measure of the functional condition of the
periodontium as well as possible aggravating co-factor
for periodontal disease.

 The percentage of teeth extracted as a result of caries
and periodontal disease were compared from age 1-74
by Kelly and Harvey (1974). It was found that, teeth
recommended for extraction due to periodontal disease
acceded that of caries or other reasons.
 Tooth mobility is considered to be of paramount
significance of establishment of diagnosis, prognosis
and treatment plan.

Factors affecting development of tooth
mobility
 Magnitude, frequency and character of masticatory forces.
 Amount of fiber bundles in the periodontium and strength of
alveolar bone.
 Physical resistance of the periodontium.
 Direction of the masticatory stress.
 Physiological and systemic factors, which influence metabolic
process of cells such as blood circulation in periodontium,
age, nutrition and general health.
 Para-functional habits and forces.

 Definitions (AAP periodontal literature review
1996).
 Tooth mobility
The degree of looseness of tooth beyond
physiologic movement.
 Fremitus
A palpable or visible movement of a tooth when
subjected to occlusal forces.

 Classification of fremitus:
Class I: mild vibrations or movements detected.
Class II: easily palpable vibrations but no visible
movements.
Class III: movements visible with naked eye.

TERMINOLOGIES
1. Physiologic / Normal Mobility
It refers to the limited tooth movement or tooth displacement
that is allowed by the resilience of an intact and healthy
periodontium when a moderate force is applied to the crown
of the tooth examined. (Muhlemann 1951).
2. Pathologic tooth mobility
It is any degree of perceptible movement of a tooth
faciolingually, mesiodistally or axially when a force is applied to
the tooth. (M.J. Perlitsh 1980).
Carranza defined it as ‘displacement that results when the
balance among the factors that maintain physiological tooth
position is disturbed by periodontal disease’.

3. Altered tooth mobility
It is an alteration of the mobility characteristics of a tooth, which
represents a transient or permanent change in periodontal
tissues. (Giargia and Lindhe 1997).
An increased TM may be associated with different physiologic or
pathologic phenomena while decrease mobility usually is result
of therapy.
4. Functional mobility
Functional mobility is the movement of teeth during function or
parafunction.
5. Normal tooth mobility
It is more during early mornings and progressively decreases.
Muhlemann (1960) reported that tooth mobility was 0.4 – 0.12
mm for 500 gm force applied. The incisors have the highest (0.1
– 0.12 mm) and molars the lowest (0.4 –0.8mm). Children and
females exhibit higher values than adults and males respectively.

6. Static tooth mobility:
It is a form of stabilized mobility. It is usually due to TFO, but
also occurs due to periodontal diseases. The periodontal
structures have become adapted to an altered functional demand.
It is self limiting and normal for that tooth with remaining bony
support.
7. Increasing / Progressive tooth mobility:
It is of progressive nature and can be identified only through a
series of repeated tooth mobility measurements carried out over
a period of several days or weeks.

8. Hypermobility
A form of increased mobility persisting after
completion of periodontal treatment. It is often
referred to as “residual mobility”. It has 2 phases, a
developing phases and a permanent phase.
9. Reduced tooth mobility
As seen in ankylosed tooth after failing replantation or
if autogenous bone grafts are placed in contact with
detached root surface.

 Mobility beyond the physiologic range is termed
abnormal or pathologic . It is pathologic in that it
exceeds the limits of normal mobility values; the
periodontium is not necessarily diseased at the
time of examination.

 Increased mobility is caused by one or more of
the following factors:
 Local Factors:
 (1) Loss of tooth support (bone loss) can result in mobility. The
amount of mobility depends on the severity and distribution of
bone loss at individual root surfaces, the length and shape of the
roots, and the root size compared with that of the crown.
 A tooth with short, tapered roots is more likely to loosen than
one with normal-size or bulbous roots with the same amount of
bone loss.
 Because bone loss usually results from a combination of factors
and does not occur as an isolated finding, the severity of tooth
mobility does not necessarily correspond to the amount of bone
loss.

 (2)Trauma from occlusion, or injury produced by excessive occlusal
forces or incurred because of abnormal occlusal habits (e.g.,
bruxism, clenching), is a common cause of tooth mobility.
 Mobility is also increased by hypofunction. Mobility produced by
trauma from occlusion occurs initially as a result of resorption
of the cortical layer of bone, leading to reduced fiber support,
and later as an adaptation phenomenon resulting in a widened
periodontal space .
 (3) Extension of inflammation from the gingiva or from the
periapex into the PDL results in changes that increase mobility.
The spread of inflammation from an acute periapical abscess
may increase tooth mobility in the absence of periodontal
disease.

 (4)Periodontal surgery temporarily increases tooth mobility for a
short period.
 (5)Pathologic processes of the jaws that destroy the alveolar bone or
the roots of the teeth can also result in mobility. Such processes
include osteomyelitis and tumors of the jaws.
 One study has suggested that pockets around mobile teeth
harbor higher proportions of Campylobacter rectus and
Peptostreptococcus micros (and perhaps p. gingivalis) than nonmobile
teeth. This hypothesis needs further verification. (Grant et al
1995)

 Systemic Factors:
 Age: Mobility is positively related to age of the
individual (Wasserman 1973). Changes in the PDL
that have been reported with aging include decreased
numbers of fibroblasts with more irregular structure.
 Sex and Race: Slightly higher incidence seen in females
and Negroes. (Wasserman 1973).
 Menstrual cycle: Burdine and Friedman (1970)
observed increased horizontal tooth mobility during
4th week of menstrual cycle.

 Oral contraceptives: Studies ( knight and wade, Das,
Bhowmick and Dutta ) indicate that periodontal
disease and attachment loss were more common
among women on pills. However Friedman (1972)
found tooth mobility to be less among ovulatory drug
users.
 Pregnancy: Ratietschak (1967) has reported tooth
mobility in pregnancy and has attributed it to physico-
chemical changes in periodontium.
 Systemic disease: Certain systemic diseases aggravate
periodontal disease i.e. Papillon Lefevere syndrome,
Down’s syndrome, Neutropenia, Chediak Higashi
syndrome, Hypophosphatasia, Hyperparathyroidism,
Acute leukemia, Paget’s disease etc

 Bone factor concept of Glickman: “When a generalized tendency
toward bone resorption exists, bone loss initiated by local
inflammatory processes may be magnified. This systemic
influence on the response of alveolar bone has been termed
the bone factor in periodontal disease. The bone factor
concept, developed by Irving Glickman in early 1950s,
envisioned a systemic component in all cases of periodontal
disease. In addition to the amount and virulence of plaque
bacteria, the nature of the systemic component, not its
presence or absence, influences the severity of periodontal
destruction.
 Although the term “Bone factor” is not in current use, the
concept of a role played by systemic defense mechanisms has
been validated, particularly by studies of immune deficiencies
in severely destructive types of periodontitis, such as juvenile
forms of the diseases.

 As a general rule, mobility is graded clinically
with a simple method.
 The tooth is held firmly between the handles of
two metallic instruments or with one metallic
instrument and one finger , and an effort is
made to move it in all directions. Abnormal
mobility most often occurs faciolingually.

Tooth mobility checked with a metal instrument
and one finger.

Tooth mobility indices
a. Miller’s Index (1938):
 The first distinguishable sign of movement.
 The movement of the tooth which allows the crown to deviate
within 1 mm of its normal position.
 Easily noticeable and allows the tooth to move more than 1mm
in any direction or to be rotated or depressed in the socket.
b. Modified Miller’s index:
 Scorer of 0, 0.5, 1, 1.5, 2.5, 3 are utilized.

c. Prichard’s index (1972)
 Slight mobility.
 Moderate mobility.
 Extensive movement in a lateral or mesiodistal direction
combined with vertical displacement in the alveolus.
d. Wasserman’s Index (1973)
 Normal
 Slight mobility less than 1 mm of buccolingual movement.
 Moderate mobility – up to approximately 2 mm of buccolingual
movement.
 Severe mobility – more than 2 mm of movement.

e. Nyman’s Index (1975)
 Zero degree – Normal – less than 0.2 mm
 Degree 1 – Horizontal / Mesiodistal mobility of 0.2 – 1mm
 Degree 2 – Horizontal / Mesiodistal mobility of 1-2 mm.
 Degree 3 – Horizontal / Mesiodistal mobility exceeding 2mm
and / or vertical mobility.
f. Flezar’s Index (1980)
 Mo - Firm Tooth
 M1 -Slight increased mobility
 M2 -Definite to considerable increase in mobility but not
impairment of function.
 M3 -Extreme mobility, a loose tooth that would be
incomparable in function.

g. Glickman’s Index (1972)
 Normal mobility
 Grade I – slightly more than normal
 Grade II – moderately more than normal
 Grade III – Severe mobility faciolingually and or / mesiodistally
combined with vertical displacement.
h. Lovdal’s Index (1959)
 First degree – teeth that were somewhat more mobile than normal.
 Second degree – teeth showing conspicuous mobility in transversal
but not axial direction.
 Third degree – teeth being mobile in axial as well as on transversal
direction.

Measurement of tooth mobility
 Measurement of tooth mobility is important to evaluate the
condition of periodontium in research oriented studies and for
diagnosis and treatment planning.
 There are numerous mobilometers, to name a few (JISP 2003
Vol. 6 No.2, Panejjer JP 1973)
 Elbrecht’s indicator (1939)
 Werner’s Oscillator (1942)
 Dreyfus vibrator (1947)
 Zinrner’s oscillograph (1949)
 Manly’s device (1951)

 Muhlemann’s Macro-periodontometer and Micro-
periodontometer, Pictons gauge (1957)
 Parfitt’s transformer (1958)
 Joel’s technique (1958)
 Goldber’s device (1961)
 Korber’s transducers, USAFSAM periodontometer
(O’Leary and Rudd 1963)
 Pameijer’s device (1973)
 Laser method (Ryden 1974)
 Persson and Svensons device (1980)
 Periotest (Schulte 1987, Simons AG, Germany)

Periotest
 The Periotest device dynamically measures the reaction of
the periodontium to a defined percussive force applied to the
tooth produced by a tapping device.
 It is connected by table to a unit which controls functions
and analyses measurements. A metal rod housed in the
interior of the hand piece, the tapping head is accelerated to a
present speed of 0.2 m/s (meters per second) and maintained
at constant speed by compensation for the influence of
friction and gravitation. Upon impact, the tooth is slightly
deflected and the tapping head is decelerated.

 The contact time between the tapping head and the
tooth varies between 0.3 and 2 ms (milli seconds). The
contact time is shorter for teeth whose alteration ability
of the periodontium is greater and which are less
mobile. The tapping head is electro magnetically
retracted into the hand piece. In 4 seconds, 16 exact
defined tapping impulses are applied to the tooth and
10,000 signals for deceleration are registered and
analyzed by the measuring unit. Invalid measurements
are recognized as such and eliminated.

 Since the contact times are not clinically
meaningful, the unit displays a value called the
“Perio test value” (PTV). The value is calculated
from the contact time between tapping head and
tooth and ranges from – 8 to +50,
corresponding to four different degrees of
mobility.

Miller’s original
classification
Mobility index PTV
No movement
distinguishable
0 -8 to + 9
First distinguishable sign
of movement
1 10 to 19
Crown deviates within 1
mm of its normal position
2 20 + 29
Mobility is easily
noticeable, and the tooth
moves more than 1mm in
any direction or can be
rotated in its socket.
3 30 + 50

Tissue reactions to the types of tooth
movements
 Tipping : when a single force is applied against the crown of a tooth, the
tooth rotates around its Centre of Resistance, a point located about halfway
down the root.
 Prolonged tipping may result in apical root resorption even if the force is
light.
 The PDL is compressed near the root apex on one side and at the crest of
the alveolar bone on the opposite side. Thus maximum pressure in the PDL is
created at the alveolar crest and at the root apex.
 It results in the formation of a hyalinized zone slightly below the alveolar
crest (when the tooth has a short undeveloped root) or at a short distance
from the alveolar crest (when the root is fully developed).

 In young patients, bone resorption
resulting from a moderate tipping
movement is usually followed by
compensatory bone formation.
The degree of such compensation
depends primarily on the presence
of bone-forming osteoblasts in the
periosteum.
 Tipping of adult teeth in a labial
direction may result in bone
destruction of the alveolar crest,
with little compensatory bone
formation.
A = Secondary Hyalinized Zone
B = Compressed PDL
X = Fulcrum

 Torque :
 During the initial movement of torque,
the pressure area is located close to the
middle region of the root. This occurs
because the PDL is normally wider in
the apical third than in the middle
third.
 After resorption of bone areas
corresponding to the middle third, the
apical surface of the root gradually
begins to compress adjacent
periodontal fibres and a wider pressure
area is established.
 Experimental studies by Reitan and
Kvam(1971-AO) have shown that
50gms of force was sufficient to cause
root movement without any
undermining resorption.

 Bodily movement:
 Bodily tooth movement is obtained by establishing a couple of forces acting
along parallel lines and distributing the force over the whole alveolar bone
surface. This is a favourable method of displacement provided the magnitude
of force does not exceed a certain limit.
 It is characteristic of the initial bodily movement that the hyalinization
periods are shorter than in tipping movements.
 Hyalinization occurs largely as a result of mechanical factors. Shortly after
the movement is initiated there is compression on the pressure side with
formation of a hyalinized zone between the marginal and middle regions of
the root.
 The short duration of hyalinization results from an increased bone resorption
on both sides of the hyalinized tissue, especially in the apical region of the
pressure side.

 The PDL on the pressure side is considerably widened by the
resorption process.
 There is gradually increased stretching of the fiber bundles on
the tension side, which tends to prevent the tooth from further
tipping. New bone layers are formed on the tension side along
these fiber bundles.

 Rotation :
 In rotation of a tooth around its long axis the force can be distributed over
the entire PDL rather than over a narrow vertical strip, whereas larger forces
can be applied than in other tooth movements.
 Histologically, the tissue transformation that occurs during the rotation is
largely influenced by the anatomic arrangement of the supporting structures.
 After rotation of the tooth, the stretch of the free gingival tissue may cause
displacement of collagen, elastic, and oxytalan fibres located even some
distance from the tooth being moved.
 Most teeth to be rotated create two pressure sides and two tension sides.
Occasionally, hyalinization and undermining bone resorption takes place in
one pressure zone while direct bone resorption occurs in the other.
 After rotation for 3 to 4 weeks, the undermining resorption is usually
completed and direct bone resorption prevails on the pressure side.

 On the tension side of the middle
third, new bone spicules are
formed along stretched fibre
bundles arranged more or less
obliquely.
 Furthermore, the periodontal space
is considerably widened by bone
resorption after rotation.
 The fiber bundles and the new
bone layers of the middle and
apical thirds rearrange themselves
after a fairly short retention period
(Reitan K. AO-1959). However,
the free gingival fibres remain
stretched and displaced for as long
as 232 days and possibly longer.
Arrangement of gingival fibers and
new bone layers formed on the
tension side, after rotation.

 Extrusion :
 (Bodily displacement of a tooth along its long axis in an apical direction)
 Extrusive movements ideally does not produce any areas of compression
within the PDL, but only tension.
 Varying with the individual tissue reaction, the periodontal fibre bundles
elongate and new bone is deposited in areas of alveolar crest as a result of the
tension exerted by these stretched fibre bundles.
 In young individuals, extrusion of a tooth involves a more prolonged stretch
and displacement of the supraalveolar fibre bundles than of the principal
fibres of the middle and apical thirds.
 In adult the fibre bundles also are stretched during extrusion, but they are less
readily elongated and rearranged.
 The force exerted must not exceed 25 to 30cN because extrusion constitutes
the type of tooth movement that requires minimal force.

 Intrusion :
 (Bodily displacement of a tooth along its long axis in an occlusal
direction)
 Light force is required because the force is concentrated in a
small area at the tooth apex. Primarily the anterior teeth are
intruded.
Stretch is exerted primarily on the principal fibres.
 An intruding movement may therefore cause formation of new
bone spicules in the marginal region. These new bone layers
occasionally become slightly curved as a result of the tension
exerted by stretched fibre bundles.
 Rearrangement of the principal fibres occurs after a retention
period of 2 to 3 months.

Microscopic features of tooth
mobility
 The excessive forces produce molecular physico-chemical
alteration of the ground substance and fibrous components of
the tissues, atrophic, degenerative and necrotic changes.
 Increased compression and tension of the periodontal ligament
are seen. With severe tension, widening, thrombosis, hemorrhage
and tearing of the periodontal ligament and bone resorption are
seen. (M.J. Perlitsh, DCNA 1980)
 There is temporary depression in mitotic and the rate of
proliferation and differentiation of fibroblasts, collagen and
alveolar bone.

(Tooth mobility revisited, According to Charles Anderegg
and David Metzler J.P. July 2001)
 Commonly used parameters, degrees of millimeter
movement gives incomplete diagnostic and prognostic
information. Current methods of grading or classifying
mobility give no indication of the mobility is
pathologic, physiologic or adaptive in nature.
 So adding the designator (A) for adaptive and (P) for
pathologic to the current grading or classification
scheme would add the critical element for determining
necessary additional occlusal or periodontal treatment.

 Pathologic mobility, as defined, would include any degree of
movement that may be reduced or eliminated once the
pathologic factors is identified and corrected. Such etiologic
factors would include inflammatory disease such as periodontitis,
occlusal factors, parafunctional habits and iatrogenic factors.
 Adaptive mobility, as defined, would include the absence of an
etiologic factor that might be improved upon to directly improve
stability by decreasing or eliminating tooth mobility.
 Adding the designator (A or P) to current descriptive
terminology would, in a broad sense, address the etiology of
existing mobility and complement current methods used to
measure the degrees of mobility.

Treatment of increased tooth
mobility
 Situation I:
Increased mobility of a tooth with increased width of
the periodontal ligament but normal height of the
alveolar bone
 If a tooth is fitted with an improper filling or crown restoration, occlusal
interferences develop and the surrounding periodontal tissues become the
seat of the inflammatory reactions, i.e. trauma from occlusion.
 If the restoration is so designed that the crown of the tooth in occlusion is
subjected to undue forces directed in a buccal direction, bone resorption
phenomena develop in the buccal - marginal and lingual - apical pressure
zones with a resulting increase of the width of the periodontal ligament in
these zones.

 The tooth becomes hyper mobile or moves away from the
“traumatizing” position. The resulting increased mobility of the
tooth should be regarded as a physiologic adaptation of the
periodontal tissues to the altered functional demands .
 A proper correction of the anatomy of the occlusal surface of
such tooth i.e. Occlusal adjustment , will normalize the
relationship between the antagonizing teeth in occlusion there by
eliminating the excessive forces.
 As a result , apposition of bone will occur in the zones
previously exposed to resorption, the width of the periodontal
ligament will become normalized and the tooth stabilized.

 Situation II:
Increased mobility of a tooth with increased
width of the periodontal ligament and reduced
height of the alveolar bone
 If a tooth with a reduced periodontal tissue support is exposed
to excessive horizontal forces, inflammatory reactions develop in
the pressure zones of the periodontal ligament with
accompanying bone resorption. These alterations are similar to
those which occur around a tooth with normal height of the
supporting structures. The alveolar bone is resorbed, the width
of the PDL is increased in the pressured tension zones and
tooth becomes hyper mobile.

 If the excessive forces are reduced or eliminated
by occlusal adjustment bone apposition to the
“pre trauma” level will occur, the periodontal
ligament will regain its normal width and the
tooth will become stabilized.
Conclusion: situation I and II
 oculusal adjustment is an effective therapy
against increased tooth mobility when such
mobility is caused by an increased width of
periodontal ligament.

 Situation III:
Increased mobility of tooth with reduced height
of the alveolar bone and normal width of the
periodontal ligament
 In this case tooth mobility can not be reduced or
eliminated by occlusal adjustment. If such increased
tooth mobility does not interfere with the patients
chewing function or comfort, no treatment is required .

 If the patient experiences the tooth mobility as
disturbing, however the mobility can in this
situations be reduced only by splinting, i.e. by
joining the mobile tooth / teeth together with
other teeth in jaw into a fixed unit –a splint .
 A-splint, according to Glossary of Periodontal
terms (1986) is an appliance designed to stabilize
mobile teeth”. A-splint can be fabricated in the
form of joined composite filling, fixed bridges,
removable partial prosthesis etc.

 Situation IV:
Progressive mobility of a tooth (teeth) as a result
of gradually increasing width of the reduced
periodontal ligament.
 Often in cases of advanced periodontal disease the tissue
destruction may have reached a level where extraction of one or
several teeth cannot be avoided. Teeth which in such a dentition
are still available for periodontal treatment may, after therapy,
exhibit such a high degree of mobility or even signs of
progressively increasing mobility – that there is an obvious risk
that the forces elicited during function may mechanically disrupt
PDL components and cause extraction of the teeth.

 Only by means of a splint will it be possible to
maintain such teeth .
In such cases fixed splint has two objectives.
 To stabilize hyper mobile teeth and
 To replace missing teeth.
Conclusion: Splinting is indicated when the
periodontal support is so reduced that the mobility of
the teeth is progressively increasing. i.e., when a tooth
or a group of teeth during functions are exposed to
extraction forces.

 Situation V:
Increased bridge mobility despite splinting.
 In patients with advanced periodontal disease it can often be
observed that the destruction of the periodontium has
progressed to varying levels around different teeth and tooth
surfaces in the dentition. They may also be distributed in the jaw
in such a way as to made it difficult, or impossible, to obtain a
proper splinting effect even by means of a cross arch bridge The
entire bridge splint may exhibit mobility in frontal and / or
lateral directions. Neither progressive tooth mobility nor
progressive bridge mobility can be accepted.

 In cases of extremely advance periodontal disease, a cross arch
splint with an increased mobility may be regarded as an
acceptable result of rehabilitation. It requires particular
attention regarding the design of the occlusion.
 In cases of severe advanced periodontal disease it is often
impossible to anticipate in the planning phase whether a bridge /
splint after insertion will show signs of instability and increasing
mobility. In such cases, a provisional splint should always be
inserted.
 Any alteration of the mobility of the bridge / splint can be
observed over a prolonged period of time and the occlusion
continuously adjusted until, after 4-6 months, it is known
whether stability can be achieved (i.e. no further increase of the
mobility).

 Conclusion V:
An increased mobility of a cross arch bridge /
splint can be accepted provided the mobility
does not disturb chewing ability or comfort and
the mobility of the splint is not progressively
increasing.

10.Pathological migration.ppt

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