Dr. Umair Shoukat Ali presented on orthodontic tooth movement and factors that affect it. Orthodontic tooth movement is a biological response to forces applied to the teeth. Continuous light forces produce the most desirable tooth movement with minimal harm. Heavier forces can result in necrosis and delayed movement. Tooth movement is regulated by chemicals like prostaglandins and leukotrienes that influence bone remodeling. Many drugs can also impact orthodontic treatment by altering these chemical pathways and affecting the rate of bone turnover. NSAIDs decrease tooth movement while corticosteroids increase it. Systemic factors like hormones and vitamins also influence the speed of orthodontic tooth movement. Close coordination with physicians is important when patients are

1. Presented by Dr. Umair Shoukat Ali.
Resident year I Orthodontics (AKUH)
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2. ORTHODONTIC TOOTH
MOVEMENT
“It is a biological response to interference in the physiological equilibrium of dentofacial complex by an
externally applied force”
2
Zimbran A, Dudea D, Gasparik C, Dudea S. Ultrasonographic evaluation of periodontal changes during orthodontic tooth movement-
work in progress. Clujul Med. 2017;90:93-7.

3. ORTHODONTIC TOOTH
MOVEMENT
STIMULUS
• Orthodontic force
Optimum Orthodontic force: ( 5 to 10 gm/cm2 )
• Produces rapid tooth movement
• Minimal patient discomfort
• No marked mobility
• Vitality of PDL maintained
• Produces frontal resorption
3
Profitt WR, Fields HW, Sarver DM. Contemporary orthodontics. 5th ed. St. Louis: Mosby; 2013.

4. ORTHODONTIC TOOTH
MOVEMENT
Orthodontic force
Bone bending
Bone deformationAltered stress pattern
Piezoelectricity Bioelectric potential
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5. ORTHODONTIC TOOTH
MOVEMENT
Piezoelectricity:
• Phenomena observed in crystalline materials
• Displacement of electrons  current generation
• Quick decay rate
• Reverse piezoelectricity
• Important in maintaining hemostasis of bone
• Doubtful in orthodontic tooth movement
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6. ORTHODONTIC TOOTH
MOVEMENT
Bioelectric potential
Orthodontic force
Bone deformation
ConvexityConcavity
ElectropositiveElectronegative
Deposition ResorptionRemodeling
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7. ORTHODONTIC TOOTH
MOVEMENT
Pressure Tension theory
Pressure in certain areas
Orthodontic force application
PDL stretchedPDL compressed
Tension in certain areas
Reduced vascularity
Vascularity increased initially then
decreased due to increased
stretching
Induces chemical changes
and inflammatory reaction
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8. ORTHODONTIC TOOTH
MOVEMENT
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9. APPLICATION OF CONTINUOUS
LIGHT FORCES
PDL fluid incompressible, alveolar bone bends1 sec
PDL fluid expressed and tooth moves within socket1-3 sec
Blood flow altered, oxygen tension changes, prostaglandins and cytokines releasedMinutes
Increased cAMP levels and differentiation begins within PDL4 hours
Tooth movement begins as osteoblast and osteoclasts remodel bony socket2 days
Blood vessels partially compressed on pressure side and dilated on tension side3-5 sec
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10. RESULT OF CONTINUOUS LIGHT
FORCES
Osteoclast
Resorption of
lamina dura from
PDL side
Frontal resorption
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11. ORTHODONTIC TOOTH
MOVEMENT
• Frontal resorption
• Accomplished by lights forces
• Least painful
• Desirable
• Least harmful to periodontium
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12. APPLICATION OF CONTINUOUS
HEAVY FORCES
PDL fluid incompressible, alveolar bone bends1 sec
PDL fluid expressed and tooth moves within socket1-3 sec
Cell death in compressed area; an area of sterile necrosis is formedHours
Cell differentiation in adjacent marrow space; undermining resorption begins
3-5
days
Osteoclast appears with adjacent bone marrow and begin attack on the underside of the bone
adjacent to necrotic PDL area
7 to 14
days
Blood vessels within PDL occlude on the pressure side3-5 sec
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13. RESULT OF CONTINUOUS HEAVY
FORCES
Heavy continuous
force
Area of sterile
necrosis
Undermining
resorption
Delay in
orthodontic tooth
movement
13
Profitt WR, Fields HW, Sarver DM. Contemporary orthodontics. 5th ed. St. Louis: Mosby; 2013.

14. ORTHODONTIC TOOTH
MOVEMENT
Delayed
tooth
movement
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15. CHEMICAL REGULATION OF
OTMPhospholipid
membrane
Leukotriene
C4. D4. E4
COX-1
(physiologic) Leukotriene A4
Arachidonic
acid
Prostaglandins
pain and fever
PGs and thromboxane
renal blood flow, mucosal
protection and hemostasis
Leukotriene B4
Cyclooxygenase Lipooxygenase
COX-2
Biosynthesis of PGs and LTs
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(Inducible)

16. CHEMICAL REGULATION OF OTM
Orthodontic force
Bio-physical reactions
Bone deformation
Compression of pdl
Tissue injury
Production of first messengers
Hormones
Prostaglandins
Production of second messengers
cAMP, Cgmp, Ca++
Increase in cells of
resorption (osteoclast)
Increase in cells of
depositions (osteoblast)
Bone remodeling
Orthodontic tooth
movement
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17. CHEMICAL REGULATION OF
OTM
• Within 1st hour  increase in PGE and IL-1
• After 4 hours of pressure  cAMP
• 4 to 6 hours of continuous force is required
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18. CHEMICAL REGULATION OF
OTM
Effect of PGs on bone and tooth movement:
• Mediators of mechanical stress
• bone resorption and root resorption
• Decreased collagen synthesis
• Increases number of osteoclast
• concentration  enhances tooth movement
• Systemic route  better effects
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19. CHEMICAL REGULATION OF
OTM
Effect of Leukotriene's on bone and tooth movement
• Important mediators of tooth movement
• Stimulate bone resorption
• Increase tooth movement
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20. DRUGS AFFECTING TOOTH
MOVEMENT
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21. DRUGS AFFECTING TOOTH
MOVEMENT
Drug
“ Any substance or product that is used to modify or explore
physiological systems or pathological states for the benefit of the
recipient ”
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22. DRUGS AFFECTING TOOTH
MOVEMENT
• During orthodontic treatment, drugs are prescribed to manage:
• Pain
• Temporomandibular joint
• Infections
22
Krishnan V, Davidovitch Z. The effect of drugs on orthodontic tooth movement. Orthod Craniofac Res. 2006;9:163-
71.

23. DRUGS AFFECTING TOOTH
MOVEMENT
• Apart from drugs, patients also consumes:
• Hormonal supplements
• Vitamins
• Minerals
23
Watted N, Proff P, Péter B, Muhamad AH. Influence of drugs on orthodontic tooth movement. J Res Med Dent Sci. 2017 Mar
25;2:9-16.

24. DRUGS AFFECTING TOOTH
MOVEMENT
NSAIDSs
• Pain control
Mechanism:
• Inhibition of cyclooxygenase pathway
• Increased MMPs
• Reduction in procollagen synthesis
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Phospholipid
membrane
COX-1
(physiologic)
Arachidonic
acid
Cyclooxygenase
Cox-2
(inducible)

25. CLASSIFICATION
Non-selectiveCOX
inhibitors:
Salicylates: Aspirin
Oxicam derivatives:
Piroxicam, Meloxicam
Fenamic acid derivatives:
Mefenamic acid
Acetic acid derivatives:
Diclofenac, Aceclofenac
Propionic acid
derivatives: Ibuprofen,
Ketoprofen
Indole derivatives:
Sulindac, Indomethacin
SelectiveCox-2
Inhibitors
Celecoxib
Rofecoxib
PreferntialCox2
inhibitors
Nimesulide
Meloxicam
Nabumetone
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26. DRUGS AFFECTING TOOTH
MOVEMENT
NSAIDs
• Inhibition of PGs  decreases tooth movement
• Decreases bone resorption
• Reduces amount of osteoclasts
• Delays orthodontic tooth movement
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27. DRUGS AFFECTING TOOTH
MOVEMENT
Fluorides
• Trace element affects hard tissue
• Increases bone mass and density
• Inhibit osteoclastic activity
• Active caries treatment  delays tooth movement
• May delay orthodontic tooth movement
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28. DRUGS AFFECTING TOOTH
MOVEMENT
Bisphosphonates
• High affinity for calcified tissues
• Used for metabolic bone diseases
• Increases osteoblastic differentiation
• Inhibits osteoclastic activity and proliferation
• Inhibits orthodontic tooth movement
• Topical application  anchoring and retaining teeth
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29. DRUGS AFFECTING TOOTH
MOVEMENT
Corticosteroids
• Increases bone resorption
• Decreases bone formation
• Increases rate of tooth movement
• Decreases plasma calcium
• Greater potential for relapse
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Phospholipid
membrane
Arachidonic acid
Phospholipase A2

30. DRUGS AFFECTING TOOTH
MOVEMENT
Immunosuppressant drugs
• Chronic kidney failure or kidney transplant
• Gingival hyperplasia
• Difficulty in maintaining oral hygiene
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31. DRUGS AFFECTING TOOTH
MOVEMENT
Cytotoxic drugs
• Disturbed overall body growth
• Damage to precursor cells (osteoblast and osteoclast)
• Risk group for orthodontic treatment
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32. DRUGS AFFECTING TOOTH
MOVEMENT
Anticonvulsants drugs:
• Seizure disorders
• Valporic acid  gingival bleeding
• Gabapentin  xerotstomia
• Phenytoin  gingival hyperplasia
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Krishnan V, Davidovitch Z. The effect of drugs on orthodontic tooth movement. Orthod Craniofac Res. 2006;9:163-71.

33. DRUGS AFFECTING TOOTH
MOVEMENT
Antibiotics:
• Anti-malarial drugs
• Tricyclic antidepressants
• Antiarrhythmic agents
• Tetracycline
Affects prostaglandin levels
Inhibits osteoclast recruitment
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34. SYSTEMIC FACTORS AFFECTING
TOOTH MOVEMENT
Hormone Effects on bone tissue Effects on tooth movement Mechanism of action
Estrogen Decreased bone resorption Decreased rate of tooth movement
Inhibits cytokine involved in bone
resorption
Parathyroid Increased rate of bone remodeling Increased rate of tooth movement
Increases cAMP formation and Ca
in target cells
Vitamin D
Increased bone resorption
Enhances establishment of supporting tooth
structure
Increased rate of tooth movement
Activates DNA and RNA within
target cells
Thyroid
Increased rate of bone remodeling
• Increased rate of tooth movement
and decreases root resorption
Activates thyroid response element
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35. CONCLUSION
• Light continuous force system is ideal for orthodontic tooth movement
• Orthodontist needs to pay attention to history of every patient before and during course of orthodontic
treatment
• Drugs can have both therapeutic effects as well as side effects during orthodontic tooth movement
• Co-ordination with the primary physician regarding the alteration of these drugs would be a great help
to the clinician
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36. REFERENCES
• Watted N, Proff P, Péter B, Muhamad AH. Influence of drugs on orthodontic tooth movement. J Res Med Dent
Sci. 2017 Mar 25;2:9-16.
• Zimbran A, Dudea D, Gasparik C, Dudea S. Ultrasonographic evaluation of periodontal changes during
orthodontic tooth movement-work in progress. Clujul Med. 2017;90:93-7.
• Krishnan V, Davidovitch Z. The effect of drugs on orthodontic tooth movement. Orthod Craniofac Res.
2006;9:163-71.
• Profitt WR, Fields HW, Sarver DM. Contemporary orthodontics. 5th ed. St. Louis: Mosby; 2013.
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