ROOT RESORPTION IN ORTHODONTICS

Root resorption is a condition characterized by a partial loss of root cementum and dentin.
Root resorption of the deciduous dentition is a physiological process and it is a necessary precursor to the eruption of permanent teeth.
Permanent teeth root resorption is a pathological inflammatory process and it can be affected by several factors

Apical root resorption can be also related to an orthodontic treatment and it can be present during the treatment or at the end of it.

This root resorption is called orthodontically- induced inflammatory root resorption (OIRR) and it is considered a distinct pathologic process.

Patient-related and treatment-related factors are involved in the onset and progression of this root resorption.1. 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.

2. 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.
Orthodontic forces applied to the biologic system act similarly on bone and cementum, which are separated by the periodontal membrane. If there are no differences in the biologic behavior of these two organs, both would resorb equally.

Since cementum is more resistant to resorption compared with the more vulnerable bone, applied forces usually cause bone resorption, which leads to tooth movement. However, resorption of the cementum and dentin may also occur
Several theories explaining the resistance of the dental tissues, especially cemental resistance to resorption, exist.

It is documented that the uncalcified mineral tissues, osteoid, precementum, and predentin are resistant to resorption and may initially prevent loss of root tissue.

These layers might contain noncollagenic materials, eg, the cells themselves, that possess potent anticollagenase propertiesAfter extensive research in this field, mainly with tooth replantation models, Andreasen, relates surface resistance to the innermost cellular layer of the periodontal ligament.

This layer supplies the protective mechanism to the root, as well as the potential for a repair.
The cementoblasts, fibroblasts, osteoblasts, endothelial, and perivascular cells are included in this layer
However, continuous pressure will eventually lead to resorption of these areas
Root resorption occurs when pressure on the cementum exceeds its reparative capacity and dentin is exposed, allowing multinucleated odontoclasts to degrade the root substance.

Acc to Rudolph ,Resorption typically attacks the root tip and

1. Root Resorption
1
Presented by:
Dr.Pooja Kale
PG IIIrd YEAR
P.M.N.M.DENTAL COLLEGE AND
HOSPITAL,BAGALKOT

2. Contents
•INTRODUCTION
•CLASSIFICATION
•NATURAL PROTECTION MECHANISM
•BIOLOGY
•FACTORS AFFECTING ROOT RESORPTION
•PREDISPOSING FACTORS
•METHODS OF ASSESSMENT
2

3. •LONG TERM EFFECTS
•GENETICS AND RESORPTION
•MANAGEMENT OF ROOT RESORPTION
•CONCLUSION
•REFERENCES
3

4. INTRODUCTION
Rootresorptionisaconditioncharacterizedbyapartialloss
ofrootcementumanddentin.
Rootresorptionofthedeciduousdentitionisaphysiological
processanditisanecessaryprecursortotheeruptionof
permanentteeth.
Permanentteethrootresorptionisapathological
inflammatoryprocessanditcanbeaffectedbyseveralfactors
4

5. •Apicalrootresorptioncanbealso
relatedtoanorthodontictreatmentand
itcanbepresentduringthetreatment
orattheendofit.
•Thisrootresorptioniscalled
orthodontically-inducedinflammatory
rootresorption(OIRR)anditis
consideredadistinctpathologic
process.
•Patient-relatedandtreatment-related
factorsareinvolvedintheonsetand
progressionofthisrootresorption.
5

6. Internal root
resorption
Pulpal infection
External root
resorption
Pulpal infection
Dental trauma
Bleaching procedures
Periodontal procedures
Impacted teeth/cysts
and tumors
Orthodontic treatment
Ankyloticroot
resorption
Severe dental
trauma
ROOT RESORPTION
6

7. There are three degrees of severity of OIIRR
(Naphtali Brezniaket al(2002) Angle Orthod
•1. 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.
•2. 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.
7
Brezniak N, Wasserstein A.--Orthodontically induced inflammatory root resorption. Part I: The basic science aspects.
Angle Orthod 2002;72:175-9

8. •3. Circumferential apical root resorption. In this process,
full resorption of the hard tissue components of the root
apex occurs, and root shortening is evident.
8

9. Protection mechanism
•Orthodontic forces applied to the biologic system act similarly on bone
and cementum, which are separated by the periodontal membrane. If
there are no differences in the biologic behavior of these two organs,
both would resorb equally.
•Since cementum is more resistant to resorption compared with the
more vulnerable bone, applied forces usually cause bone resorption,
which leads to tooth movement. However, resorption of the cementum
and dentin may also occur
9

10. •Several theories explaining the resistance of the dental tissues,
especially cemental resistance to resorption, exist.
•It is documented that the uncalcified mineral tissues, osteoid,
precementum, and predentin are resistant to resorption and may
initially prevent loss of root tissue.
•These layers might contain noncollagenic materials, eg, the cells
themselves, that possess potent anticollagenase properties.
10

11. After extensive research in this field, mainly with tooth replantation
models, Andreasen, relates surface resistance to the innermost cellular
layer of the periodontal ligament.
This layer supplies the protective mechanism to the root, as well as the
potential for a repair.
The cementoblasts, fibroblasts, osteoblasts, endothelial, and
perivascular cells are included in this layer
However, continuous pressure will eventually lead to resorption of
these areas
11

12. •Root resorption occurs when pressure on the cementum
exceeds its reparative capacity and dentin is exposed, allowing
multinucleated odontoclasts to degrade the root substance.
•Acc to Rudolph ,Resorption typically attacks the root tip and
travels coronally.The portion of the root nearest the pulp
appears to be the last to give way. This process is exactly
opposite to that of tooth formation
12

13. •Andreasendefinesthreeexternalrootresorptiontypes:
–Surfaceresorption,whichisaself-limitingprocess,usually
involvingsmalloutliningareasfollowedbyspontaneousrepair
fromadjacentintactpartsoftheperiodontalligament.
–Inflammatoryresorption,whereinitialrootresorptionhas
reacheddentinaltubulesofaninfectednecroticpulpaltissueor
aninfectedleukocytezone.
–Replacementresorption,wherebonereplacestheresorbed
toothmaterialthatleadstoankylosis.
Andreasen FM. Transient root resorption after dental trauma:the clinician's dilemma.J Esthet Restor
Dent.2003;15(2):80–92
13

14. AccordingtoTronstad,inflammatoryresorptionisrelatedto
thepresenceofmultinucleatedcellsthatcolonizethe
mineralizedordenudedcementalsurface.
Hecharacterizestwokindsofinflammatoryresorption.
Transientinflammatoryresorptionoccurswhenthestimulationtothe
damageisminimalandforashortperiod.Thisdefectisusually
undetectedradiographicallyandisrepairedbyacementum-liketissue.
Whenstimulationisforalongperiod,Tronstadsuggeststheterm
progressiveinflammatoryresorption.Ankylosisistheresultofan
extensivenecrosisoftheperiodontalligamentwithformationofbone
ontoadenudedareaoftherootsurface.
Tronstad L. Root resorption--etiology, terminology and clinical manifestations.Endod Dent
Traumatol.1988;4(6):241–52.
14

15. Rootresorptionafterorthodontictreatmentissurface
resorption,ortransientinflammatoryresorption.
15

16. Biology of root resoprtion
Orthodonticforceinitiation
stimulatetheremodelingof
alveolarbone,whichresultsin
toothmovement.
Beforethisremodeling,initial
changesinresponsetoalocal
compressionofPDLinclude
reductioninwidthandvascular
changes.
PDLchangesoccurmostnoticeably
atpressuresitesduringtooth
movement.
16

17. Tissuenecrosisisevidentatallstagesandatvaryingdegreesof
progressionduringorthodontictoothmovement.
Theseareaaredevoidofcellularelementsasseeninhistologic
sections,commonlyreferredasHYLANIZATION.
Resultsofhistologicstudiesstronglysuggestthattherootresorption
occursinresponsetodamageinitiatedbyorthodontictreatmentto
periodontalligament.
Ryghandco-workershaveshownthatcementumadjacentto
hyalinized(necrotic)areasinPDLis“marked”bythiscontactand
thatosteoclastcellsattackthismarkedcementumwhenthePDLarea
isrepaired.
17
Rygh P. Orthodontic root resorption studied by electron microscopy. Angle Orthod. 1977;47:1–16.

18. Osteoclastcellsresorbnotonlynecrotictissue,butalsotheroot
surfaceindiscriminately.
Rootsurfacechangedoesnotbecomeapparentbeforecellular
changesinadjacentPDLandBone.
Inhumanteeth,changesareobservedin3-5weekafterinitiationofa
lightforce.
Initialstagesmononucleargiantcellsalongtherootsurfaceassociated
withareasofdamagedPDLareseen.
•Advanced stages are typified by Odontoclast-The odontoclastis the
root-resorbing cell. It is a large pleomorphic, usually multinucleated,
cell formed by monocyte precursors like cells with ruffled borders.
18

19. Theresidualmatrixcoveringthesurfaceoftheresorptiondefectsconsists
ofexposedcollagenfibrils.
Boththehealingprocessandearlystagesofrootresorptioninvolveahigh
percentageofMononucleargiantcells.
Mononucleargiantcellsmayalsobeinducedtotransforminto
odontoclastsbytheexposedmineralizedrootsurface.
Hence,itissuggestedthatMononucleargiantcellsnon-selectivelyremove
theprecementumlayertogetherwithadjacentnecroticPDL.
19

20. •Theorganicmatrixdegradation:
•AccordingtoJonesandBoyde,theosteoclastiscredited
forbothdemineralizationofthecalcifiedtissueand
degradationoftheorganicmatrixafterdemineralization.
•Cysteineproteinasesofosteoclasticoriginwerefoundtobe
importantintheremovaloforganicmatrices.
20

21. Somearticlesstatearesorbingactivity,asaresponsetomechanicalor
chemicalstimulibytheperiodontalligamentcells.
Thisprocessisregulatedbyhormones(parathyroidandcalcitonin),
neurotransmitters(substanceP,vasoactiveintestinalpeptide,and
calcitoningenerelatedpeptide),andcytokinesormonokines
(interleukin-1alpha,interleukin-1beta,interleukin-2,tumornecrosis
factor,andinterferon-gamma).Itwasalsosuggestedthatthe
osteoclastsarecontrolledbyosteoblastsinmanyways.
21

22. Initiation, Cessation and Repair
Firsthistologicdetectionofrootresorptionvaryfrom1weekto
afewweeks.
Progressionofrootresorptionintermsofdepthandnumberof
lacunaehasbeenfondtoincreasewithcontinuationofforce.
Cessationofprocess:fewinvestigationsconcludethat
resorptionceaseswithterminationofforceapplication,
whereasotherstudiesshowthatprocesscontinuesevenafter
forceapplication.
Presentlycessationismorelikelylinkedtocompleteremoval
ofnecrotictissuethanforceapplication.
22

23. •Repairofresorptionlacunaehasbeenobservedasearlyas3-
5weeksaftertheinitiationoflightorthodontictooth
movement.
•Examinationoftherootsurfacesofteeththathavebeen
movedrevealsrepairedareasofresorptionofbothcementum
anddentinoftheroot.
23
Breznlak N and Wassersteln A .Root resorption after orthodontic treatment: Part 1. Literature review.
Am. J. Orthod. Dentofac. Orthop. 1993;103(1):62-66.

24. Cementum(andDentin,ifresorptionpenetratesthroughthecementum)removed
formtherootsurfaceisrestoredbytheformationofDentinocementaljunction
correspondingtothatformedatOdontogenesis.
Cementallacunaebecomefullyanatomicallyreconstructed.Deepdentinallacunae
arerepairedbyathincementallayerresultinginanirregularrootshape.
Afterbothtypesofrepair,theperiodontalligamentwidthisusuallynormal.Root
contourisfrequentlyfollowedbybonecontour,whichincreasestoothanchorage
withoutcompromisingfunction.
Rootremodelingisaconstantfeatureoforthodontictoothmovement,but
permanentlossofrootstructurewouldoccuronlyifrepairdidnotreplacethe
initiallyresorbedcementum.
24

25. Loss of Root Apex
25
T
O
O
T
H
L
E
N
G
T
H
CAVITIES coalesce
at the APEX

26. FACTORS AFFECTING ROOT
RESORPTION
26

27. Predisposing Patient [Biologic] Factors
›Individualsusceptibility
›Genetics
›Systemicfactors
›Nutrition
›Genderofthepatient
›Chronologicage
›Dentalage
›Toothstructure
›Traumatizedteeth
›Presenceofrootresorptionbeforeorthodontictreatment
›Endodonticallytreatedteeth
›Adversehabitsasnail-biting,tonguethrusting
›Specifictoothvulnerabilitytotoothresorption
27

28. •TreatmentRelated[Mechanical]Factors
–Typeoforthodonticappliancesused
–Magnitudeofappliedforces
–Directionoftoothmovement
–Amountoftoothmovement
–JigglingandOcclusaltrauma
•CombinedFactors
–Treatmentduration
–Rootresorptiondetectedradiographicallyduringorthodontic
treatment
–Rootresorptionafterapplianceremoval
–Relapse
28

29. MECHANOTHERAPY AND ROOT RESORPTION :
•Root resorption after orthodontic mechanotherapy is a well-known fact. The
dependence of this iatrogenic sequela on various mechanotherapeutics
performed has been studied extensively, but the results have been conflicted
•Many parameters such as:
–the type of malocculsion,
–extraction versus nonextraction,
–the type of appliance used
(removable, fixed, or functional appliances),
–the type of tooth movement performed,
–the duration of force application
29

30. •The magnitude of force, as well as rigid fixation of the arch-wire with
brackets or the use of full-size rectangular wires in bracket slots, could
be the most important factors predisposing a tooth to the resorptive
process
30
Brin I. External apical root resorption in Class II malocclusion: A retrospective review of 1-versus 2-phase
treatment. Am J Orthod Dentofac Orthop. 2003; 124:151-6

31. Root resorption among different
malocclusions
Thereisastatisticallysignificantdifference
betweenClassIandClassIIDivision1
malocclusions,withthelatterexhibiting
moreresorption.
Jansonetal(2007)reportedahigher
resorptionpotentialforClassIIDivision2
casesincomparisonwithClassI,ClassII
Division1,andClassIIIpatients.
Therationalewasthattheintrusion
mechanicsnecessarytocorrectdeepoverbite
inthesecases,aswellastheexcessivelabial
torqueneededtocorrectthepalatal
inclinationoftheincisors,werethecause
31

32. •However it can be inferred from the published literature that
all types of malocclusion are prone to root resorption when
exposed to orthodontic treatment.
•Harris D et al (2006): showed that the volume of the root
resorption craters after intrusion was found to be directly
proportional to the magnitude of the intrusive force applied.
The mesial and distal surfaces had the greatest resorption
volume, with no statistically significant difference between
the 2 surfaces.
Harris D et al .Physical properties of root cementum: Part 8. Volumetric analysis of root resorption craters after application of
controlled intrusive light and heavy orthodontic forces: A microcomputed tomography scan study.Am J Orthod dentofacial
Orthop 2006;130:639-47
32

33. Extraction versus Nonextraction
modalities.
Moststudiesrevealedthatbothtechniqueshavethe
potentialtoproducedamage,withextractiontherapy
beingpotentiallymoredetrimental.
Someauthorsobservedadefiniteincreaseinroot
resorptionfollowingextractiontherapy.
Othersreportedalackofcorrelationbetweenroot
resorptionandtreatmentwithextractionornonextraction.
33
Graber L,Vanarsdall R,Vig k and Huang G.orthodontics current principles and techniques.2017.1
st
ed.

34. TYPE OF APPLIANCE
•The challenge for research these days is to determine
which of the various fixed appliance techniques—standard
edgewise, Begg, straight-wire, bioefficient, or Speed—
causes the most resorption
•Studies have reported different values for resorption
following the different types of appliance therapy
34
Janson GRP, De Luca Canto GDL, et al. A radiographic comparison of apical root resorption after orthodontic
treatment with 3 different fixed appliance techniques: Am J Orthod Dentofacial Orthop 2000:118:262-273.

35. •Itwasrecentlyreportedthatalowerincidenceof
resorption,aswellasamountofrootresorption,inpatients
treatedwiththeBIOEFFICENTTHERAPY.
35

36. The incidence rate of root resorption was 3.72 times
higher when extractions were performed as part of Begg
appliance therapy.
An increased amount of root resorption with the Begg
appliance has also been extensively reported in the
previous literature.
L'Abeeand Saderinkobserved root resorption in all three
stages of Beggmechanics, with the second stage
exhibiting the least severity.
36

37. Mayoral,AJO1982 however, reported a low incidence of root
resorption following Beggmechanics and emphasized the
importance of using light forces to diminish damage to the roots.
This report stands alone at present, but the use of light forces to
prevent root damage seems to be an interesting subject and
potentially fruitful approach for future research.
37

38. A comparison of standard edgewise with straight-wire
appliances reveals statistically insignificant results except for
one study, (MavraganiM et al EJO 2000 )which reported
increased resorption for central incisors in the edgewise group.
When sectional mechanics were compared with continuous
arch mechanicsreported the same resorption potential
38

39. Root resorption and Invisalign®
•Gay G et al (2017) -investigated the incidence
and severity of RR in adult patients treated with
aligners during class I treatments. They evaluated
that every patient showed a minimum of one tooth
with root length reduction.
•They also concluded that Severe RR affected
mostly the upper lateral incisors and lower lateral
and central incisors.
Gay G et al. Root resorption during orthodontic treatment with Invisalign®: a radiometric study.Progress
in orthod 2017;18(12):1-9.
39

40. Type of tooth movements
Ofthevarioustoothmovements,intrusionandtorquearemost
commonlyassociatedwiththeresorptionprocess.Thisis
evidentwhenstudyingClassIIDivision2correctionaswellas
Beggmechanics.
Theintrusionperformedinthefirststageandtorquinginthe
thirdstagemaketheBeggtechniquemorevulnerableto
resorption.
40
Brezniak N. Root resorption after orthodontic treatment. Part II. Literature review. Am J Orthod Dentofac
Orthop.1993; 103:138-46.

41. Displacement of the root apex horizontally or torquinghas
been proven beyond doubt to produce root resorption.
The highest incidence of root resorption is reported to
occur when 3 to 4.5 mm of torquingmovement were
performed.
Resorption with tads mechanics were recently evident
when the studies was done.
41

42. Treatment time
The length of treatment time and root resorption have
been positively correlated by almost all studies, which
have shown that increased treatment time makes tooth
roots more prone to the iatrogenic response
42
AryalN&JingM.RootResorptioninOrthodonticTreatment:ScopingReview2017;7(2):47-52.

43. Acaret al AO 1999 evaluated the effect of the type of force
applied—continuous versus interrupted—on the resorption
pattern and observed less severe apical blunting and smaller
resorption-affected areas when interrupted force was applied.
Their findings are in agreement with study in this regard Maltha
JC et al, EJO 1996and emphasize the use of less detrimental
discontinuous forces (in the form of elastic usage, instead of
elastomeric chains) during space-closure stages of orthodontic
mechanotherapy
43
Magnitude of applied force

44. •Ballard D et al.(2009) studied the Continuous vs intermittent controlled
orthodontic forces on root resorption.They concluded that : Intermittent
force produced less root resorption than continuous force
•Buccally directed intermittent forces for 8 weeks (after 14 days of
initial continuous force application, the intermittent force application
was obtained with a 3-day resting period followed by a 4-day force
application period) produce significantly less total root resorption than
a similarly directed continuous force of the same magnitude and
duration.
Ballard D. Allan S. Petocz P and Darendeliler M. Physical properties of root cementum: Part 11. Continuous vs intermittent controlled
orthodontic forces on root resorption. A microcomputed-tomography study. Am J Orthod Dentofacial Orthop 2009;136:8.e1-8.e8
44

45. •GonzalesC.HotokezakaH.DarendelilerMand
YoshidaNconcludedthattheresorptionandrepairprocesses
duringtheearlystagesofretentionarebalanced,andmostofthe
reparativeprocessoccursafter4weeksofpassiveretentionafter
theapplicationoforthodonticforce.Frequentorthodontic
reactivationsshouldbeavoidedtoallowrecoveryandrepairof
rootsurfacedamage.
Gonzales C .Hotokezaka H..Darendeliler M and Yoshida N .Repair of root resorption 2 to 16 weeks after the application
of continuous forces on maxillary first molars in rats: A 2-and 3-dimensional quantitative evaluation. Am J Orthod
Dentofacial Orthop 2010;137:477-85
45

46. TOOTH SPECIFICITY
Evaluation of the vulnerability of specific teeth to the resorption
process in the literature has resulted in common agreement among
authors that the maxillary incisors are the teeth that are the most
susceptible to the process
But controversy still exists regarding which incisors resorb the most:
the centrals or the laterals The majority of studies published reported
that central incisors were more susceptible to the process, except for
two recent studies, which favored the lateral incisorsare equally prone
for resorption.
46
Graber L,Vanarsdall R,Vig k and Huang G.orthodontics current principles and techniques.2017.1
st
ed.

47. •Followingtheincisorsinsusceptibilitytoresorptioninthemaxillary
archarethemolars,followedbythecanines.Inthemandibulararch,
themostresorptionvulnerabletoothisthecanine,followedbythe
lateralandcentralincisors.
•Amongposteriorteeth,themostresorbedarethemandibularmolars
(withthedistalrootexhibitingmoreresorption),followedby
maxillarymolars,mandibularpremolars,maxillaryfirstpremolars,and
maxillarysecondpremolars
47

48. Beck and Harris,described the
relationship of mechanotherapyto root
resorption in the distal roots of molars.
According to them, anchorage
archwirebends at the mesial of molars,
for bite opening, cause the distal roots
to be compressed in the tooth sockets,
thereby initiating root resorption.
48

49. It would be of interest to quantify the consequences of buccal tooth
root lengths with the bioprogressivetechnique in which the buccal
molar roots are moved toward the cortical plates for anchorage.
49

50. ROOT SHAPE
•Various authors have evaluated abnormalities in root shape and
its association to the resorptive process.
•Among differently shaped root ends (normal, blunted,
dilacerated, pipette shaped, pointed, and incomplete), the least
resorption was observed in blunted root ends and the greatest
was seen in pointed or tapered root ends.
50

51. •This phenomenon is explained by the fact that the pressure from
the axial component of orthodontic forces is felt most at the root
apex regions, which are abnormal in shape.
•This results in localized ischemic necrosis, which denudes the
precementum and cementoblasts, permitting colonization of
dentinoclasts.
51

52. In comparison to the normal root shape, dilacerated roots show the
most resorption, followed by pipette-shaped and incomplete roots.
Levanderand Malmgre(1988) noted that blunt shaped roots are at
greater risk of resorption.
Therefore any abnormal root shape observed in pretreatment
diagnostic records should be observed with caution and should be
monitored throughout the treatment period for any iatrogenic damage.
52

53. Root length and root resorption
•Root length and resorption were found to
have a positive correlation. The studies in
this regard report that longer roots are more
prone than shorter ones to resorption,
because of the greater displacement
required to produce an equal amount of
torque, versus shorter roots.
53

54. ROOT CANAL TREATMENT AND ROOT
RESORPTION
54
Theincreaseindentindensityfollowing
endodontictreatmentproducesincreased
resistancetowardtheresorptionprocess,
incomparisontountreatedteeth
Howeversomestudiesfoundno
differenceb/wtheendodonticallytreated
toothandnormaltooth(WalkerSLetal
(2017EJO).

55. Trauma and root resorption
•Previoushistoryoftraumaandthepresence
ofpretreatmentrootresorptionhavebeen
positivelycorrelatedwithrootresorption
seenafterorthodontictreatment.
•Thereexistsarelationshipbetweencortical
plateproximityandincreasedroot
resorption.
•Allthesefindingspointtowardthe
importanceofobtainingpretreatment
diagnosticrecordsandproperevaluation,
sothatanyriskelementscanbeidentified
anddescribed 55

56. Studiestodatehaveagreedwithapositive
correlationbetweenanincreaseinoverjet
androotresorption.
Themainreasonsattributedtothis
phenomenonarethegreateramountof
torqueandgreaterrootdisplacements
requiredtocorrectexcessoverjet.Theuseof
interruptedratherthancontinuousforceis
onewaytoreducethisproblem
56
BaumrindS AJO 1996, HoriuchiA et al AJO 1998 ,SameshimaGT, AJO
2001& McNabS et al AJO 2000
OVER BITE AND OVER JET

57. Crestal alveolar bone levels.
Sharpeetal(1987)conductedextensiveresearchonrelapse,apical
rootresorption,andcrestalalveolarbonelevels.Theyfound
possiblerelationshipsbetweenincreasedrootresorption,decreased
crestalbonelevels,andorthodonticrelapse.
Rootlengthandcrestalalveolarboneheightareconsideredto
influencethetotalareaofsubcrestalperiodontalsupportforatooth.
Areductioninrootlengthaswellasinthecrestalbonelevelwill
predisposeatoothtowardrelapsebecauseofthedecreased
resistanceagainsttheforcescausingrelapse
57

58. Atsomestageintoothmovementduringrelapse,theseteeth
mightundergofurtherrootresorptionandcrestalboneloss.
Anumberofauthorshaveresearchedtheimportanceof
periodontalsupportandrootlengthinrelationtoorthodontic
toothmovement.
Theyallagreedthattheperiodontalconditionofpatients
shouldbemonitoredthroughouttreatmentandduringthe
posttreatmentperiodtopreventrelapsetendenciesandenhance
thelongevityofthedentition.
58
Krishnan V .Root Resorption with Orthodontic Mechanics: Pertinent Areas Revisited.Aust Dent J.2017 ;62(1):71-77

59. AGE, GENDER, AND ETHNICITY
•Biologic factors, such as age at the start of treatment and
gender, have long been associated with risk factors for the
initiation of root resorption.
•Age at the start of orthodontic treatment and incidence of root
resorption have been poorly correlated in almost all recent
studies
59
Graber L,Vanarsdall R,Vig k and Huang G.orthodontics current principles and techniques.2017.1
st
ed.

60. Sameshimaand Sinclair (2001) claim that mandibular
anterior teeth demonstrate significant root resorption when
orthodontic treatment is carried out in adults. Otherwise,
their study agrees with previous findings of a lack of
correlation between age and root resorption
60

61. Conflicting results have been seen when gender is considered.
Two studies supported the view that female patients are more
prone to the process, while others cite evidence for men.
Sameshimaand Sinclair state that male subjects are more prone to
the process but the results are statistically insignificant. The
majority of the studies support a lack of correlation between
gender and resorption.
61

62. •The relationship between ethnicity and root resorption was
evaluated . The results showed less severity among Asians in
comparison to Caucasians and Hispanics (SameshimaGT AJO
2001 et al).
62

63. Micro-osteoperforations& orthodontic
root resorption
•ChanEetal.(2018)conductedastudytoinvestgatethetheeffectsof
micro-osteoperforationsonorthodonticrootresorptionwith
microcomputedtomography.Theyconcludedthat:Premolarstreated
withmicro-osteoperforationexhibitedsignificantlygreateraverage
totalamountsofrootresorption
•Thetotalaveragevolumetricrootlossofpremolarstreatedwithmicro-
osteoperforationwas42%greaterthanthatofthecontrolteeth.
Chan E et al.Physical properties of root cementum: Part 26. Effects of micro-osteoperforations on orthodontic root resorption: A
microcomputed tomography study. Am J Orthod Dentofacial Orthop 2018;153:204-13
63

64. occlusaltrauma
•1. Restorative buildups, used to increase the vertical dimension
by 2 mm for 4 weeks, caused root resorption along the sides of
the teeth during the active bite-increase period.
•2. The level of pain was not correlated to the amount of root
resorption.
•3. To improve our current understanding of the detrimental
effects of bite raisers, they should be tested in different heights
and different experimental durations.
Cakmak F et al. Physical properties of root cementum: Part 24. Root resorption of the first premolars after 4
weeks of occlusal trauma. Am J Orthod Dentofacial Orthop 2014;145:617-25
64

65. OTHER PREDISPOSING FACTORS
FOR ROOT RESORPTION
•A review of the published literature reveals numerous reports with
positive as well as negative associations of various factors predisposing a
patient to the resorption process evaluated the individual variation
expressed in patients.
•They reported that long, narrow, and deviated roots increased the risk of
resorption.
65
Tekale P &Vakil K. Orthodontics and root resorption: A review. Europ J Parma:2015;vol 2(2) pp-589-595.

66. Some reports describe a positive correlation between
various habits, eg, lip/ tongue dysfunction with a history
of thumb sucking and nail biting
66

67. •Dentalanomaliessuchastoothagenesis,
peg-shapedlaterals,densinvaginatus,
taurodontism,ectopiceruption,and
abnormallyshortrootshavebeenevaluated
recently.
•Morerecentlyastudyreportedthat
invaginatedteethmayhavemalformed
rootsmoreoftenthannoninvaginatedteeth
howeverdentalinvaginationtypeI(milder
form)cannotbeconsideredasarisk
factorforapicalrootresorptionduringthe
treatment.
67
Kook YA et al. peg shaped and small lateral incisors not at risk of root resorption .Am J Orthod .2003;123(3):253-258.

68. •The correction of impacted maxillary canines was recently identified
as a risk factor for root resorption.
•This might be a result of the ectopic eruption path through which the
orthodontist moves the teeth or intrusive forces compressing the
periodontal ligament of incisors while acting as anchorage.
68

69. •Drugs such as corticosteroids and alcohol (through
vitamin D hydroxylation in the liver) have been
identified as predisposing factors.
•An increased risk for root resorption among asthmatic
patients was reported by (McNab et al 1999. AJO DO).
•Asthma, in particular, results in an imbalance between
T helper 1 and T helper 2 lymphocytes, the latter
responsible for the pulmonary synthesis and release of
inflammatory mediators, such as interleukins 4, 5, 6, 10
and 13.
•They did a tooth-specific analysis and found a higher
incidence of resorption for the roots of maxillary
molars.
69

70. •A concept of the "hypofunctionalperiodontium," associated
with non-occluding teeth, as a risk factor for root resorption
following orthodontic treatment. (SringkarnboriboonS,etal J
Dent Res 2003 )
70

71. METHODS OF ASSESSMENT
•Quantitativeaswellasqualitative
analysesoftheresorptionprocess
arerequiredtopreventthe
occurrenceofthemostcommon
iatrogenicdamage following
orthodontictoothmovement
71

72. VARIOUS METHODS
Clinical Histological Radiographical
Biologic
markers
72
Radiographs remain the most important tool for
evaluation of pretreatment, in progress, and post
treatment status of tooth roots.

73. Radiology offers a variety of choices—periapicals,
panoramic, and digital radiographs, as well as
lateral cephalogramsand the type chosen depends
on the specific tooth location.
Sameshimaand Asgarifar(2002) compared
periapicaland panoramic films for pretreatment
analysis of root shape and posttreatment
assessment of apical root resorption.
They recommended periapicalfilms, for patients at
high risk for root resorption and bone loss. They
also found that root abnormalities were clearer in
periapicalfilms.
73

74. •Armstrong D, KharbandaOP, PetoczP, DarendelilerMA(2003)
did a study to determine if apical root resorption is related to the type of
appliance used and/or the direction and amount of tooth movement.
•The pre and post-treatment tooth lengths of the maxillary and
mandibular first molars and incisors were measured on panoramic
radiographs of 114 subjects. with pre-and post-treatment
cephalometricradiographs.
74

75. Within the groups four teeth decreased significantly in
length when the pre-adjusted appliance was used and four
teeth when the Speed appliance was . Only one tooth was
shorter when the Tip-Edge appliance was used.
Lower incisors were significantly shorter post treatment if
the apices were moved close to the lingual cortex.
75

76. They reported that when panoramic radiographs are used to
assess treatment-induced changes in the lengths of the incisors,
apical resorption is only one factor that should be considered.
The images of lower incisors proclined during treatment may
be foreshortened and/or the apices may lie outside the focal
plane: both may result in 'shorter' teeth post-treatment.
Because of the confounding factors panoramic radiographs
may not be a reliable method of determining apical root
resorption.
76

77. •GlennT.Sameshima,KatiO.AsgarifarAO2001
reportedthat,incaseswheretheapicesareobscuredor
otherfactorsarepresentthatmightsuggesthigherriskfor
rootresorptionorverticalboneloss,periapicalfilms
shouldbeordered.
•Theuseofpanoramicfilmstomeasurepre-and
posttreatmentrootresorptionmayoverestimatetheamount
ofrootlossby20%ormore.
77

78. •However, periapicalsinclude projection errors and are not
reproducible.
•To overcome the problem, Dermautand De Munck
published formulae that correct for angulationof a tooth
relative to the x-ray film, at least as compared to a prior
film:
78

79. •(Crown A X Root B) / (Root A X Crown B) =
Root B/Root A
•in which "crown" is the distance from the
incisive edge to the cementoenamel junction,
"root“ is the distance from the CEJ to the root
apex, and A and B are two examinations, such
as pretreatment and posttreatment.
79

80. •Pretreatment to posttreatment comparison of tooth length
(incisal edge to root apex) or root length (cementoenamel
junction to root apex) is still the main measurement method
for assessment of root resorption
80

81. Root resorption index for quantitative
assessment of root resorption:
1.Irregular root contour.
2.Root resorption apically, amounting
to less than 2 mm. of the original root
length
3.Root resorption apically, amounting
to from 2 mm. to one third of the
original root length.
4.Root resorption exceeding one third
of the original root length.
81
The grading criteria of Sharpe et al and scoring criteria of Levanderand
Malmgrenare the most commonly used.

82. 82
Beck B, Harris EF.AJO 1994
Grade 0 -no root resorption;
Grade 1 -mild resorption, root with
normal length and irregular contour only
Grade 2 -moderate resorption with small area of
root loss and apex exhibiting almost straight contour;
Grade 3 -accentuated resorption with loss of almost
one third of root length;
Grade 4 -extreme resorption with loss of more than
one third of root length.

83. •Becauseofthehighdegreeof
reproducibility,someauthorshaveused
lateralcephalogramsforassessmentof
resorption.
•Themainproblemwiththismethodis
thatitcanbeusedonlyforevaluationof
damagetotheincisors,andtheproblems
ofposteriorteethwillnotbeevident.
83

84. Recent imaging system
•LevanderetalandWestphalenetal.(2007)through
independentresearchconductedstudiesondiagnosticutilityof
digitalimagesandreportedthatthesensitivityofthese
radiographswascomparableorbetterthantheconventional
film-basedradiographs.
84

85. Inaddition,digitalimagesofferimmediatevisualizationandareductionin
radiationexposuretopatients.
Theuseofcomputerizedtomographyforevaluationofresorptionandits
sensitivityinsite-specific(mesial,distal,buccal,orlingual)detectionofthe
processhasbeenreviewedrecently(BrezniakN,AO2002)
Themaindrawbacksforthisexcellentinnovativetechnologyareitscostand
theneedforspecialequipment.
85

86. •Thephysicalpropertiesofcementumin
root-resorbedteeth,includingitsmineral
composition,havebeenevaluated.
•Thisispossiblewiththeuseofultra-micro
indentationsystemstodeterminethe
hardnessandelasticityofhuman
cementum.
•Theresultsofthesestudieswerefoundto
beveryencouraging,astheymadeit
possibletoquantifycementumatdifferent
sites.
•Thismethodmightalsohelpinidentifying
theexactamountofdamageproducedby
mechanotherapy.
86
Malek S, Darendeliler MA, Swain MV. –Physical properties of root cementum: A new method for 3-dimensional
evaluation. Am J Orthod Dentofacial Orthop 2001 Aug; 120(2): 198-208

87. Biological markers
Mah and Prasad (E JO 2004) discovered biologic markers for
root resorption in crevicular fluid.
In this study, the measured dentin sialophosphoproteins; levels
of them were high in gingival crevicular fluid that was in
proximity to resorbing primary and permanent tooth roots.
In control areas without root resorption, they observed low
levels of these proteins. This research has provided us with a
simple and practical method for predicting initiation of the
process.
87
Mah J, Prasad N. Dentine phosphoproteins in gingival crevicular fluid during root resorption.Eur J Orthod 2004;26:25-30

88. •BalducciL,RamachandranA,HaoJ,NarayananK,EvansC,George
A(.ArchOralBiol.2007)didastudytoidentifyandquantifyextracellular
matrixproteins,dentinmatrixprotein1(DMP1),dentinphosphophoryn
(PP),anddentinsialoprotein(DSP)inthegingivalcrevicularfluid(GCF)
ofsubjectsundergoingorthodontictreatment
•ResultsrevealedasignificantdifferenceintheconcentrationsofDMP1,PP
andDSPbetweencontrolandrootresorptiongroups.
•TheyreportedthatDSPandPPcouldbesuitablebiologicalmarkersfor
monitoringrootresorptionduringorthodontictreatment,sinceasignificant
differenceinthelevelofthesedentinspecificproteinsisdetectedinall
groups
88

89. •Mass spectroscopy analysis: The main goal was to
identify novel biomarkers associated with root resorption
and the protocol was able to identify 2789 and 2421
proteins in the control and resorption pooled samples,
respectively
MithunK,HarshithaV,AshithM,NaveenKumarand,AnilKumar.RootResorptioninOrthodontics:ARecent
Update.IndianJournalofPublicHealthResearch&Development.October-December2017;8,(4):307-312. 89

90. Elisa combined with electrochemistry
•The electrochemical results extended the lower end of
detection from 5 pg per milliliter (by spectrophotometry) to
0.5 pg per millilitre thus it is a reliable and sensitive
method to detect dentine sialophosphoprotein in gingival
crevicular fluid
90
MithunK,HarshithaV,AshithM,NaveenKumarand,AnilKumar.RootResorptioninOrthodontics:ARecent
Update.IndianJournalofPublicHealthResearch&Development.October-December2017;8,(4):307-312.

91. Role of drugs in decreasing root resorption
Theroleofdrugsindecreasingrootresorptionhasbeenreportedin
somerecentpublications.Onesuchreportdescribedtheroleof
bisphosphonates,whichproducedadose-dependentreductioninroot
resorptionwhentestedonrats
Alatlietal1996recentlychallengedthishypothesis,statingthatbis-
phosphonatesinducedcementumsurfacealteration,inhibited
formationofacellularcementum,anddelayedformationofcellular
cementum,therebyactuallyincreasingthevulnerabilityofthetooth
roottotheresorptiveprocess.
91

92. •Villa et al (2005) has evaluated the effect of a nonsteroidal
anti-inflammatory drug (NSAID), nabumetone, on tooth
roots and found it to reduce root resorption, as well as pain
caused by intrusive orthodontic force, without affecting
tooth movement.
92

93. •Jerome J, et al 2005did a study to determine if COX-2
inhibitors like Celebrexare effective in protecting root
resorption associated with orthodontic forces
•Administration of COX-2 inhibitors like Celebrex during
the application of orthodontic forces does not interfere with
tooth movement and appears to offer some slight protection
against root resorption.
93

94. •AliRezaSekhavatetal(2011)reportedthatoraladministration
ofmisoprostol,aprostaglandinE1analogcanbeusedto
enhanceorthodontictoothmovementwithminimalroot
resorption.
•SomedrugssuchasLithiumchloridecanattenuate
orthodonticallyinducerootresorptionduringorthodontictooth
movementanditseffectontoothmovementisinsignificant
94

95. •Tetracycline: Anti-inflammatory properties of tetracyclines(and
their chemically modified analogues) unrelated to their
antimicrobial effect has shown a significant reduction in the
number of mononucleatedcells on the root surface. Such cells
have been related to root resorption
95
MithunK,HarshithaV,AshithM,NaveenKumarand,AnilKumar.RootResorptioninOrthodontics:ARecentUpdate.Indian
JournalofPublicHealthResearch&Development.October-December2017;8,(4):307-312.

96. Effect of systemic fluoride
•Matthew Foo, Alan Jones, and M. Ali Darendeliler( AJO 2007)
did a study to test the effect of systemic fluoride intake on root
resorption in rats .
•They concluded that fluoride reduced the size of resorption
craters but the effect is variable and is not statistically
significant
Foo M Jones A and Darendeliler M. Physical properties of root cementum: Part 9. Effect of systemic fluoride intake on root
resorption in rats. Am J Orthod Dentofacial Orthop 2007;131:34-43
96

97. Role of hormones and cytokines
•Theeffectofhormonesandcytokinesinreducing
resorptionhasbeenevaluated.Themainhormone
attributedtothiswasL-thyroxine
•Itisassumedthatitincreasestheresistanceofcementum
anddentinelasticactivity.
•Shirazietal1999confirmedthisrecentlythrough
administrationofincreaseddosesofL-thyroxine,which
producedlessrootresorption.
97

98. •The major cytokine evaluated for correlation with the resorptive
process was prostaglandin E2.
•While two studies confirmed its role in the process,(Williams S.
et al BrudvikP et al )a evaluation demonstrated no effect for
this cytokine on either the depth or the number of resorption
lacunae found in resorbedtooth roots.
98

99. •A report by Bialy et al (AJO 2004) evaluated the effect of low-
intensity pulsed ultrasound (LIPUS) on the healing process of
orthodonticallyinduced root resorption in humans.
•They found a significant decrease in areas of resorption and
number of resorption lacunae in LIPUS exposed premolars.
•The result of this study is encouraging, as it demonstrates a non-
invasive method to reduce root resorption in humans.
99

100. LIPUS (low-intensity pulsed ultrasound)
•LIPUS at 100 or 150 MW/cm2 groups displayed decreased RR,
decreased osteoclast numbers and activity levels, increased
OPG/RANKL expression ratios. High-power SEM revealed
reparative cementum in the LIPUS treated samples. LIPUS
regulates osteoclast differentiation via the OPG/RANKL ratio,
evoking a reparative effect on orthodontically induced root
resorption in rats
100
MithunK,HarshithaV,AshithM,NaveenKumarand,AnilKumar.RootResorptioninOrthodontics:ARecentUpdate.Indian
JournalofPublicHealthResearch&Development.October-December2017;8,(4):307-312.

101. LONG-TERM EVALUATION OF RESORBED TOOTH
ROOTS: IS IT A CONTINUOUS PROCESS?
•The literature supports the view that there is no apparent
increase in resorption after termination of active orthodontic
treatment.
•Some amount of repair is found to occur, including smoothing
and remodeling of the cemental surface as well as the return of
a normal periodontal membrane width.
•The original root contours and length are never re-established,
but the function of the tooth apparatus is not severely affected.
101

102. •The main problem cited for these teeth on a long-term basis
is their reduced suitability as abutments for prosthetic
replacements, because of their less favorable crown/root
ratio.
•Further, these teeth will be less resistant to trauma, and
even marginal periodontitis can make their prognosis
critical.
102

103. GENETICS AND RESORPTION: IS
THERE A LINK?
AlandmarkstudybyHarrisetalin1997provideduswith
statisticallysignificantdataexhibitingaheritablecomponent
forrootresorption.Itrevealedhowapersonmaybeinnately
susceptibletotheprocess.
Theeffectofgenemutationonrootresorptionisexpressed
whenthemasticatoryapparatusisstressedbyorthodontic
treatment.
However,theresearcherswerenotabletodescribethe
biochemicaleventsregulatedbythegenotypetoexpressthe
resorptionpotential.
103

104. •More recent research has been directed toward finding the
specific genes involved in the process, the chromosome
loci, and the relevant clinical applications.
•Al-Qawasmiet al conducted breakthrough research in this
regard with the help of DNA isolation and analysis from
buccalswab cells.
104
Al-Qawasmi RA, et al. Genetic predisposition to external apical root resorption. Am J Orthod Dentofacial
Orthop 2003:123:242-252.

105. They found significant evidence of linkage disequilibrium of
interleukin-lBpolymorphism in allele 1 and external apical root
resorption.
Persons homozygous for the IL-1B allele1have a 5.6 fold
increased risk of external root resorption greater than 2 mm as
compared with those who are not homozygous for the IL-1B
allele1
The observed low production of IL-1B in allele 1 could result in
less catabolic bone modeling at the cortical bone interface.
This might result in a prolonged stress concentration on tooth
roots, triggering a cascade of fatigue-related events leading to root
resorption.
105

106. 106

107. MANAGEMENT OF ROOT
RESORPTION
107
PRE TREATMENT DURING TREATMENT AFTER TREATMENT

108. BEFORE TREATMENT
General considerations. The patient/parents must be informed
about the risk of OIIRR as a consequence of orthodontic treatment.
The rule of thumb is better to inform early than to later apologize.
Familial considerations. A recent study has confirmed previous
results concerning the strong familial association of OIIRR. When
treating a new patient whose close sibling was previously treated,
orthodontists should try to obtain the final diagnostic records
including the radiographs of any treated siblings.
Mithun K .Root Resorption in Orthodontics: A Recent Update. Indian Journal of Public Health
Research & Development. 2017;8(4):307-312.
108

109. •Generalhealth.Thesystemicconditionofthe
patientshouldbecarefullyconsidered.
•Itwasrecentlyreportedthatpatientswithchronic
asthma,bothmedicatedornonmedicated,havean
increasedincidenceofOIIRRthatisconfinedtoa
slightbluntingofthemaxillarymolars.
•Thisfindingmightresultfromthecloseproximity
oftherootstotheinflamedmaxillarysinusand/or
thepresenceofinflammatorymediatorsinthese
patients.
109

110. •The dentition. --Orthodontic treatment does not stop root
development.
•Teeth with incomplete root formation at the onset of
orthodontic treatment continue to develop roots during
treatment, but the roots reach somewhat less than their
expected root length potential.
110

111. •Gender and age: Most studies have not found a consistent
association between gender and OIIRR.
•Parameters that should be evaluated from radiographs
include:
–root morphology,
–endodontic treatment,
–bone morphology,
–ectopic, and transplanted teeth.
111

112. When a patient has
transplanted teeth,
orthodontists are advised
to wait at least three
months after
transplantation before
exerting force on the teeth.
With regard to the risk of
OIIRR, full assimilated
transplanted teeth react to
orthodontic force in a way
comparable to that of
normal teeth.
112

113. •No orthodontic force can imitate the natural harmless physiologic
force. Although no difference in OIIRR has been found at low and
high force levels (50 g to 200 g),
•It is still recommended not to overload the teeth with high force
levels. High levels of force will tend to increase the damaged areas
in the periodontal ligament, which may lead to more extensive
OIIRR.
113

114. During treatment
•Thenewlight-forcerectangularwires
thatareusedintreatmentasinitialwires
havebecomeverypopularinthelast
decade.
•Butuseofthesewiresmightincreasethe
jigglingmovementsduringthefirststage
oftreatment,exposingtheroottomore
OIIRR.
•Thereforeitissuggestedproceedingwith
thisinitialstepwithcaution,untilmore
definitivedataarepublished.
114

115. After 6-12 months of treatment, periapical
radiographs of the teeth involved in this
treatment should be obtained in order to detect
the occurrence of OIRR early.
Since, in most published data, the incisors are
the teeth that tend to be most affected, the
changes in their root shape might project on
the overall phenomenon.
When OIIRR is detected in the six-month
periapical radiograph, treatment should be
halted for two to three months with passive
archwires.
115

116. •Halting treatment for three months in one arch while working on the
other is a practical solution that can be implemented without
changing the treatment protocol
•When the treatment is durable, periapical radiographs should be
obtained, with the following consideration.
•When minimal OIIRR is present, the aforementioned procedure is
sufficient
116

117. prosthetic solutions to close
spaces,
releasing teeth from active
arches if possible,
stripping instead of extracting,
early fixation of resorbed
teeth.
Orthognathicsurgery can also
be considered in extreme
cases, yet it cannot be relied
on to prevent OIIRR.
117
However, when severe resorption is identified, the treatment goals should be reassessed with
the patient; for example, alternative options might include

118. Pause during the treatment
•Effect of a pause in active treatment on teeth that had
experienced apical RR during the initial 6-month period
with fixed appliances. The results showed thatthe amount
of RR was significantly less in patients treated with a pause
(0.4 -0.7 mm) than in those treated with continuous forces
without a pause (1.5 -0.8 mm)
118

119. After treatment
•Final records including radiographs are recommended and are
even mandatory. If OIIRR is present on the final radiographs, the
patient/parents should be informed.
•Final records and radiographs will be useful for the future
orthodontic treatment of siblings.
119

120. •If severe OIRR is present on the final radiographs, follow-up
radiographic examinations are recommended until OIRR is no longer
evident.
•Cemental repair or termination of the active processes of OIRR occurs
naturally after the appliance removal. If it does not occur, sequential
root canal therapy with calcium hydroxide may be considered.
•Gutta-percha filling is the definitive therapy only after root resorption
ceases
120

121. •Several anecdotal reports have demonstrated the stability of
teeth with severe resorption over the years.
•However, the use of teeth with severe resorption as abutment
teeth should be reconsidered.
•Retaining the teeth with fixed appliances should be done with
caution. Occlusal trauma of the fixed teeth or segment might
lead to extreme OIIRR.
121

122. Conclusion
•OIIRRisaniatrogenicconsequenceoforthodontictreatment.
•Keepingthisinmind,orthodontistsshouldtakeallknownmeasures
•toreduceitsoccurrence.Althoughseveralprotectiveprocedureshave
•beensuggested,noneofthemcanactuallypreventOIIRRwithany
•degreeofcertainty.
•Anindividual'sgeneticbackgroundisthesinglestrongestpredictor
•ofresorption,asshownbyfamilialanalysis.
122

123. •This suggests that research will lead to a biochemical assay, perhaps of
crevicular fluid, that would flag patients at particular risk of EARR.
Such research is ongoing.
•In future, more genetically based studies, as well as other basic science
research, might clarify the exact nature of OIIRR and hopefully help to
prevent or even eliminate this phenomenon.
123

124. •BrezniakN, Wasserstein A.--Orthodonticallyinduced
inflammatory root resorption. Part I: The basic science aspects.
Angle Orthod2002;72:175-9.
•BrezniakN, Wasserstein A.--Orthodonticallyinduced
inflammatory root resorption. Part II: The clinical aspects.
Angle Orthod2002; 72:180-184.
•JansonGRP, De Luca Canto GDL, et al.--A radiographic
comparison of apical root resorption after orthodontic
treatment with 3 different fixed appliance techniques: Am
J OrthodDentofacialOrthop2000:118:262-273.
124
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127

128. Thank you
128