Root Resorption Guide - Causes, Classification and Management

ROOT
RESORPTION
INDIAN DENTAL ACADEMY

Leader in continuing dental education
www.indiandentalacademy.com

CONTENTS
INTRODUCTION
CLASSIFICATION OF ROOT RESORPTION
BIOLOGY OF ROOT RESORPTION
CONTEMOPORARY REVIEW OF ETILOGICAL
FACTORS
MANAGEMENT
 CONCLUSION




Root resorption is a physiologic or pathologic
process occuring as a result of changes seen in
the tooth or surrounding periradicular tissues
characterized by loss of tooth structure over
the root surface.



External apical root resorption ( EARR ) of
permanent teeth is uncommon but a frequent
sequelae to orthodontic tooth movement.


CLASSIFICATION
OF ROOT
RESORPTION
•ACCORDING TO TYPE

Physiologic root resorption occurring on
deciduous teeth during eruption of permanent teeth
Pathologic root resorption occurring on
permanent roots

•ACCORDING TO LOCATION
Internal root resorption


External root resorption

•ACCORDING TO SEVERITY
Surface resorption occurs commonly periapically as
microdefects on the root surface and stops when the
instigating agent is removed and there is repair of cementum.
Inflammatory resorption Occurs when root resorption
progresses into the dentinal tubules to reach the pulpal tissue.
Replacement resorption Produces ankylosis of a
tooth because bone replaces the resorbed bone substance.

CLASSIFICATION OF
ORTHODONTICALLY INDUCED ROOT
RESORPTION
According Brezniak and Wasserstein (AJO-DO 1993)

Cemental or surface resorption with
remodeling
 Dentinal resorption with repair (deep
resorption)
 Circumferential apical root resorption.



Cemental or surface resorption with remodeling: In

this process, only the outer cemental layers are resorbed,
and they are later fully regenerated or remodeled. This
process resembles trabecular bone remodeling.
Dentinal resorption with repair (deep resorption) In

this process, the cementum and the outer layers of the
dentin are resorbed and usually repaired with cementum
material. The final shape of the root after this resorption
and formation process may or may not be identical to the
original form.
Circumferential apical root resorption. In this process,
full resorption of the hard tissue components of the root apex
occurs, and root shortening is evident. Different degrees of apical
root shortening are, of course, possible.

ETIOLOGY
Root resorption may occur as a result of :
•Dental trauma / surgical procedures /
Infections
•Orthodontic treatment
•Pressure from tumors / cysts
•Irritation from chemicals ( Eg. H2O2
during
bleaching)

ROOT RESORPTION DUE TO PULPAL
INFECTION:
Injury to the precementum or predentin, infected
dentinal tubules may stimulate the inflammatory
process with osteoclastic activity in the
periradicular tissues or in pulpal tissues,
consequently initiating external or internal root
resorption.

ROOT RESORPTION DUE TO
PERIODONTAL INFECTION :
Infrequently, external root resorption may
occur after injury to the pre-cementum, apical
to the epithelial attachment, followed by
bacterial stimulation originating from the
periodontal sulcus.


ROOT RESORPTION DUE TO
IMPACTED TOOTH , TUMOR
PRESSURE :
Pressure root resorption can be observed during
the eruption of the permanent dentition,
especially of maxillary canines ( affecting
lateral incisors ) and mandibular third molar
( affecting madiubular second molars ).
Tumors and osteosclerosis impingning on the
root of the tooth could also be an etiological
factor for pressure resorption
ANKYLOTIC ROOT RESORPTION
In severe traumatic injuries ( intrusive
luxation or avulsion with extended dry
time ), injury to the root surface may be so
large that the healing with cementum is
not possible, and one may come into
contact with the root surface without an
intermediate attachment apparatus. This
phenomena is termed dentoalveolar
ankylosis.

ROOT RESORPTION DUE TO ORTHODONTIC PRESSURE
The injury originating in the orthodontic root resorption is from the pressure
applied to the roots during tooth movement. Continuous pressure stimulates
the resorbing cells in the apical third of the roots, a possibility of significant
shortening of the root.

Teeth are asymptomatic and the pulp is usually vital unless the pressure of the
operative procedure is high, which disturbs the apical blood supply.

GENETIC PREDISPOSITION TO
EXTERNAL APICAL ROOT
RESORPTION IN ORTHODONTIC
PATIENTS

J Dent Res 82(5): 356-360, 2003

The linkage results for D18S64, which lies close to
the candidate gene TNFRSF11A, provide suggestive
evidence that this locus, or a closely linked one,
contributes to the genetic component of root
resorption and the strength of this linkage, make
TNFRSF11A a candidate gene for further study

BIOLOGY OF ROOT RESORPTION
Orthodontic force

Compression of
PDL

Removal of
hyaline material

Removal of
superficial
surface of
cementum

Root
resorption


Hyalinization
& inflammation

Activation of
osteoclasts

THE REPAIR PROCESS
Morphologically, the repair process of the resorbed
lacunae is described as beginning from the periphery,
the bottom, or all directions.
It begins about two weeks after force removal, with
the placement of acellular cementum succeeded by
cellular cementum. This process is evident in 38%
and 82% of human premolar lacunae after two and
five weeks, respectively.

QUANTIFICATION OF
ROOT RESORPTION :
Broadly, two methods have been used to quantify
resorption :
ORDINAL SCALE DATA :
Visually assessed grades of resorption assigned
RATIO SCALE DATA:
Measurements with calipers or some computer aided
device

THE ORDINAL SCALE USED TO MEASURE ROOT
RESORPTION
BY LEVANDER E. & MALMGREN

GRADE 2
GRADEI0
GRADE 3
GRADE 4 of of
ooOne-fourth
Evidence
Scalloping
Normal
erosion
and blunting
Intact root
the of atleast
oLoss root
periapically
of apex
morphology
resorbed
one-half the
oApical length
originallength
Root outline
probably and
is smoothnot
yet affected
continuous
oDistance

between the
root and
lamina dura is
uniform

CONTEMPORARY REVIEW OF
ETIOLOGICAL FACTORS ASSOCIATED
WITH ROOT RESORPTION
Janson et al reported a higher resorption potential for
class II div 2 cases in comparison with class I , class II div
I and class III patients.
Among

all the extraction patterns, extraction of all the
first premolars showed the greatest resorption potential.
McNab

et al has reported a higher incidence of
resorption, as well as amount of root resorption in patients
treated with the Begg appliance as compared to the
Edgewise technique.

TYPE OF TOOTH MOVEMENT
Intrusion and torque movements are found to be
most commonly associated with the resorption
process.
TYPE OF FORCE
Interrupted forces were shown according to
studies to cause less severe apical blunting and
smaller resorption- affected areas.


ROOT SHAPE AND LENGTH
Among differently shaped root ends, the least
resorption was observed in blunted root ends and
the greatest was seen in pointed or tapered root
ends.
Longer roots are more prone than shorter ones to
resorption, due to the greater displacement
required to produce an equal amount of torque,
versus shorter roots.

EFFECT OF DRUGS
•Drugs such as corticosteroids and alcohol have been
identified as predisposing factors.
• An increased risk for root resorption among asthamatic
patients was also recently reported by Mc Nab et al
•The changes they observed were attributed to changes in
the immune system of patients


MANAGEMENT


A review of literature supports a temporary halt in
orthodontic treatment for a period of 4 – 6 months.

The resorptive process ceases and the reparative
process starts within this period.
Drugs

such as bisphosphonates, NSAIDs, various
hormones and cytokines including prostaglandin E2
and L-thyroxine etc have been tried and tested to
little clinical success.

CONCLUSION
External apical root resorption is an
iatrogenic consequence of
orthodontic treatment. Keeping this
in mind, we as orthodontists should
take all known measures to reduce its
occurrence

Root Resorption Guide - Causes, Classification and Management

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Root Resorption Guide - Causes, Classification and Management