Enamel demineralization Enamel fracture Root resorption and factors affect: - Biological factors - Mechanical factors Pain and damaged to pulp Gingivitis Alveolar bone loss Oral ulceration Allergic reaction *** general risks associated with orthodontic treatment: - Facial esthetics - TMD - Relapse - Failure of treatment

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Dr. Mohammed Alruby
Risks of orthodontic treatment
Prepared by:
Dr. Mohammed Alruby

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Dr. Mohammed Alruby
Enamel demineralization
Enamel fracture
Root resorption and factors affect:
- Biological factors
- Mechanical factors
Pain and damaged to pulp
Gingivitis
Alveolar bone loss
Oral ulceration
Allergic reaction
*** general risks associated with orthodontic treatment:
- Facial esthetics
- TMD
- Relapse
- Failure of treatment
Orthodontic treatment is not without risk, the risks associated with treatment can arise as direct
consequence of placing an appliance or be secondary to treatment itself

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Dr. Mohammed Alruby
Risks from appliance
Principle risks arise from the use of fixed appliance and these can affect the teeth, periodontium,
and soft tissues
1- Enamel demineralization:
The incidence of demineralization during fixed appliance therapy is high and can results in the
development of enamel opacities on the labial surface of the teeth.
50% of pts undergoing treatment affected by demineralization due to:
a- High diet sugar
b- Long term
c- Poor oral hygiene
During treatment, the chances of developing enamel opacities can be reduced by the regular use
of topical fluoride supplements
The use of 0.05% sodium fluoride mouth wash ------ reduce the incidence of white lesions
The use of fluoride releasing bonding agent such as glass-ionomer will reduce caries level during
treatment
2- Enamel fracture:
The removal of a fixed appliance bonded to caries enamel, there is small risks of fracture of enamel
at enamel- dentinal junction, if bracket bond strength is too high. The debonding failure occurs at
bracket base-cement junction
In early ceramic bracket system, the bond strength was enhanced by the mechanical bonding
chemically ---------- that lead to increase the bond strength and allow significant fracture of enamel
during debond
Modern ceramic is designed with features that facilitate easier debonding which reduce risk of
enamel fracture
3- Root resorption:
External root resorption is an almost universal finding following treatment but usually not
significant and not affect long term health of the teeth
From 1% to 5% of orthodontically treated tooth report severe root resorption when more than
one- third length of root was lost, the greatest amount of root resorption occurs in lateral maxillary
incisors
N: B:
Orthodontically induced inflammatory root resorption (OIIRR) was a common finding and has
been reported on 37% (Lupi et al 1996)
The maxillary incisors are most commonly affected followed by mandibular incisors and 1st
molars.
= risk factors for root resorption:
- Level of orthodontic force
- Unusually shaped roots: blunted, short, pipette
- History of dento-alveolar trauma
- Continuous orthodontic force
- Excessive orthodontic force
- Intrusive force
- Lingual root torque
- Large distal movement of anterior teeth to reduce over jet
- Pushing apices of teeth into cortical bone

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Dr. Mohammed Alruby
** root resorption index:
Grade I: irregular root, contour
Grade II: root resorption at apex, less than 2mm
Grade III: root resorption from 2mm to one third of the root length
Grade IV: root resorption more than one third of the root length
Apical root resorption: ARR:
Definition: loss of root material which is idiopathic or obscure origin, it is one of the most common
complication associated with orthodontic treatment
Andreson defined three types of root resorption:
a- Surface
b- Inflammatory
c- Replacement
= RR occurs during orthodontic treatment is surface or transient inflammatory type
= the mechanics of RR in permanent teeth is still not fully understood, however different theories
have been proposed;
1- Classic pressure theory: stated by Schwartz, Retain, and others, the pressure created by
orthodontic force within the periodontal membrane can cause RR when exceed the optimal
limit (20 -26gm /cm)
2- Immunologic theory: stated by King Court who found an antibody against the root antigen
in mice
3- Bio-mechanical theory: that stressed upon the possible role for prostaglandin E in the
process of root resorption
According Schwartz, RR ceases when the force decrease to the level below the optimal force.
== retain stated that RR is followed by formation of cementoid tissue within the resorption lacuna
which delay the occurrence of new resorption and initiate healing. Complete repair may take place
within 30 to 70 days after force removal, while deep undermining resorption healed by thin
cemental layer leaving a root defect
Factors affect RR during orthodontic tooth movement:
I- Biological factors:
1- Individual susceptibility:
RR seems to vary from person to another and in the same person from time to time, this may be
due to deviation in: metabolic rate, nutrition, response to immune system
2- Genetics:
The role of genetics is strongly suggested; however, the mode of transmission is still uncertain
3- Systemic factors:
Becks related RR to: endocrine imbalance, Paget disease, Cleidocranial dysostosis
4- Nutrition:
Becks found RR in animals with calcium and vit D deficiency
5- Chronological age:
RR is more common in adults than in adolescent
6- Dental age:
Rosenberg reported that, teeth with complete roots showed less RR than that with incomplete root
7- Sex:
Females showed RR more frequently than males
8- Pre-existing RR:
Presence of RR before treatment increase risk of RR during treatment from 4 to 77%
9- Habits:

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Dr. Mohammed Alruby
Abnormal pressure habits increase the incidence of RR
10-Root morphology:
Deviated, convergent roots and those with a blunt apex show higher incidence of RR than normal
roots
11-Previous trauma:
Traumatized tooth will be at greater risk of RR during treatment
12-Endodontically treated tooth:
Some reported higher incidence of RR in Endodontically treated teeth, other suggested that, they
are more resistance due to density and hardness of dentine
13-Density of alveolar bone:
The more-dense the alveolar bone, the greater the incidence pf RR, this fact is demonstrated when
flushing the root against the labial or lingual cortical bone
14-Type of malocclusion:
Some authors reported higher incidence of root resorption in pt with class II division 2
malocclusion, however Vandar found no correlation between type of malocclusion and RR
15-Individual teeth susceptibility:
Some teeth are more sensitive to stimuli than others. The frequency is: U2, U1, L12, L6, L5, U6
II- Mechanical factors:
1- Type of appliance:
= The degree of RR is depending on the type of appliance used, Linge and Linge reported that,
fixed appliance cause more RR than removable one, on the other hand, some investigator links the
RR to the jiggling force of removable appliance
= It was found that the RR occurs with higher incidence with certain treatment modalities such as:
class I, II, cross elastics, headgear therapy, rapid maxillary expansion, anchorage preparation
with tip back
= On the other hand magnets was found to decrease the potential of RR
= No significant differences in degree of RR was found between extraction and no-extraction
treatment
2- Type of tooth movement:
Intrusion causes more RR than other tooth movement, the frequency is:
- Intrusion
- Tipping
- Torque
- Bodily
- Expansion
3- Type, magnitude and force duration:
Continuous force causes more root resorption than intermittent force, however some authors link
intermittent force with jiggling force which more determinant to RR
The higher the magnitude of force, the greater incidence of RR, the greater duration of force the
greater RR.
4- Relapse:
Retain suggested that the force of relapse is not strong enough to cause RR. Sharp et al found a
higher incidence of RR in pts showed relapse than in pts show no relapse
Prediction of RR:
RR is almost un-predictable; however, the following guidelines may be helpful:

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Dr. Mohammed Alruby
1- Root morphology
2- Stage of root development
3- Radiographic evidence of RR before treatment
Finally:
The patient should be informed about the risk of RR during treatment, and follow with apical
radiograph
If RR did not occur in 6 -9 months after beginning of treatment it not likely occurs after
If RR demonstrated radiographically, stop the force and re-evaluate treatment objectives to see if
possible to compromise or terminate the treatment
4- Pain and damaged to the pulp;
Orthodontic treatment especially with fixed appliance, can be painful, this pain subsides within
few days of appliance activation
= pain is not common finding during orthodontic tooth movement but some pts experienced some
problems ranging from discomfort until appreciable pain particularly after appliance activation
= there is a wide range of individual variation in pain threshold
= generally pt can receive normal dose of non-steroidal anti-inflammatory and analgesics as;
phenobarbital and paracetamol. Aspirin has been reported to delay tooth movement.
5- Pulpal changes and possible devitalization:
= More force for pushing of the apex though the cortical bone can result in loss of vitality during
treatment
= Loss of vitality is a rare complication of orthodontics
= Orthodontic tooth movement is considered as a controlled trauma to the tooth, therefore changes
similar to that seen after traumatic injuries to the teeth would be suspected
= it has been thought that orthodontic forces cause:
a- Compression of pulpal vessels
b- Depletion of oxygen tension
c- Disturbance in pulpal circulation
Studies:
 Thomas radiographically investigate the effect of orthodontic force on dental pulp, he found
a changes similar to those found after traumatic injuries in some cases
 Others: investigate the effect of orthodontic extrusion on dental pulp tissues, the result
demonstrate:
a- Circulating disturbance, with congested and dilated vessels
b- Odontoblastic degeneration
c- Edema of the pulp
d- By fourth week, fibroblastic changes take place
6- Gingivitis and periodontal disease:
= The component of fixed appliance creates retention areas for plaque accumulations and prevent
proper access for optimal cleaning
= the microbial activity within plaque layer lead to gingivitis which may be progress to destructive
periodontitis with loss of attachment and development of infra-bony pockets
= most clinical studies have been reached to two conclusions:

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Dr. Mohammed Alruby
a- Provided that, oral hygiene measures are maintained during orthodontic treatment, so
significant injury will occur to periodontium
b- On the other hand, neglecting oral hygiene during treatment will result in greater adverse
effect on periodontium especially in adult patients
= two important legal aspects lie on the operator side:
a- Initiating treatment without resolving the pre-existing condition
b- Continuing orthodontic treatment without regular evaluation of periodontal condition
= long term effect on periodontium:
Sadowsky studied the long term effect of orthodontic treatment on periodontium in group of adults
treated with fixed appliances compared with untreated group with same: age, sex, dental
awareness, socioeconomic, type of malocclusion. He found that orthodontic treatment not
contribute in any way to long term periodontal status
7- Alveolar bone loss;
A small loss of alveolar bone height following orthodontic treatment has been reported in relation
to teeth adjacent to extraction sites
Active periodontal disease increase bone loss
Periodontal disease should be treated and stable before start of treatment, more movement of teeth
in labial or buccal direction during treatment can result in bony dehiscence and gingival recession.
8- Oral ulceration:
Traumatic ulceration in early stage of treatment by the extension of wire from tubes.
Ortho-phosphoric acid itching causes burn if contact with soft tissue
9- Allergic reactions:
Orthodontic wires and brackets contain nickel, and nickel allergy increase in frequency, intra-oral
signs are non-specific and have been reported to include erythematous areas and severe gingivitis
despite good oral hygiene
10-Headgear injury:
A number of intra-oral and extra-oral injuries have been reported with the use of headgear,
Types:
a- Catapult injury: occurs when the face bow is disengaged from the tubes while still attached
to the head or neck-strap resulting in springing back into the soft tissues of the mouth or
face
b- Nocturnal dis-engagement: occurs when the face-bow is unintentionally detached from
headgear during sleep and the inner bow causes intra-oral or extra-oral injury
= the most serious reported injury from headgear is ocular damage which can result in partial or
total blindness in one or both eyes.
Penetrating injury of eye can be relatively a symptomatic in initial stages, however oral micro-
organisms transmitted by the face bow can rapidly infect the eyes
Safety of headgear:
a- Self-releasing of head cap or neck strap, prevent catapult injury by detaching when force
exceeds
b- Locking face bow prevent dis-engagement at night by physically locking the face bow into
the appliance
Generalized risks associated with orthodontic treatment

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Dr. Mohammed Alruby
1- Facial esthetics:
Position of dentition within the soft tissue of the face affect the facial profile
More retraction of upper incisors affects the shape of mid face
Incisors Proclination associated with expansion can result in poor facial profile
2- Relapse:
Relapse is a partial or full return of original malocclusion following orthodontic treatment as:
- Rotated teeth
- Lower incisors crowding
- Changes in labiolingual position of lower incisors
- Expansion of lower intercanine width
- Spacing
3- Failure of treatment:
Successful treatment requires significant cooperation which some pt find difficult, there is less
problem with adult pts who are highly motivated toward treatment.
Pt who fail to complete course of treatment may result in unsatisfactory occlusion
4- Temporomandibular joint dysfunction:
The question of whether orthodontic treatment can cause, cure or has a little or no effect upon
development of TMD has been extensively studied in the dental researches
Several researches have been carries out and led us to more confusion because of their conflicting
conclusion.
From the results of these studies, can divide the authors opinion into the following schools:
a- First school:
Marbach, Perry and Vander weele among others have stated that orthodontic treatment can cause
TMD and attributed this effect to certain treatment modalities such as first premolar extraction,
headgear, chin-cup, class II elastics
Roth and Williamson also stated that TMD can result from orthodontic treatment that not finished
according to gnathological standard as poor finishing -------- non-functional occlusal contact
b- Second school:
Williamson, Ingervaland among others have stated that certain treatment modalities such as:
- 2nd
molar extraction
- Non-extraction treatment
- Face mask
- Functional appliances
Can actually cure or at least prevent TMD
c- Third school:
Rickets, Parker, and Thompson among others suggested that orthodontic treatment can cause and
cure TMD, based on:
- Age of pts
- Treatment strategies
- Mechanics
d- Fourth school:
Green, Bell, Sadwesky, and Begol among others found no cause- effect relationship between
orthodontic treatment and TMD, they concluded that: orthodontic treatment dies not influence
TMD and generally not increase or decrease the risk of developing TMD in later life