Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
YASMIN MOIDIN
2008 Batch
Al Azhar Dental College
Thodupuzha
Orthodontic tooth movement (OTM) is a
complex
biomechanical process which
is initiated by the clinician with the
applicati...
 Several

factors affect and modify the
nature and amount of orthodontic tooth
movement.
The
most
significant
mechanical
...
Physiologic tooth movement designates
primarily the slight tipping of the
functioning tooth in its socket and
secondarily,...
 Tooth

movement during masticatory
function depends upon the location of
neutral axis of the functioning tooth.
 Neutra...
 During

chewing , the teeth tips slightly
around the neutral axis as fulcrum.
 Tooth is displaced because of bending of...
 Different

teeth move in different
directions during eruption
 During eruption, upper molar teeth move
mainly in mesial...
 Migration

of teeth is a slow tooth

movement
 Direction of movement is usually mesial
and occlusal
 This corresponds ...
Each tooth is attached to and
separated from the adjacent alveolar
bone by a heavy collagenous supporting
structure , the ...
1.
2.
3.

Collagen fibres
Cellular elements
Tissue fluids
 The

major component of the PDL is a
network of parallel collagenous
fibers, inserting into cementum of the
root surface...
 These

supporting fibers run at an
angle, attaching farther apically on the
tooth than on the adjacent alveolar bone
 T...
 The

principle cellular elements in the
PDL are undifferentiated mesenchymal
cells and their progeny in the form of
fibr...
 Nerve

endings are found within the
ligament, both the unmyelinated free
endings associated with perception of
pain and ...
 The

PDL space is filled with fluid and is
derived from the vascular system
 Tissue fluids acts as a shock absorber
During masticatory function, the teeth and
periodontal structures are subjected to
intermittent heavy forces. Tooth contac...
.

Pain is normally felt after 3 to 5 seconds
of heavy force application ,indicating that
the fluids are expressed and cr...
TIME (SECONDS)

EVENT

LESS THAN 1

PDL fluid incompressible, alveolar
bone bends, piezoelectric signal
generated

1-2

PD...
The phenomenon of tooth eruption makes it
plain that forces generated within the PDL
itself can produce tooth movement
 T...
 This

mechanism also indicates active
stabilization of the teeth against
prolonged forces of light magnitude
 Active st...
1.
2.

Two major theories are:
The bioelectric theory
The pressure-tension theory
The bioelectric theory relates tooth
movement at least in part to changes in
bone metabolism controlled by the
electric si...
1. PIEZOELECTRICITY
2. STREAMING POTENTIAL
3. BIOELECTRIC POTENTIAL
It is a phenomenon observed in crystalline
materials in which deformation of a
crystal structure produces a flow of
electr...
1.

2.

Quick decay rate:- When a force is
applied a piezoelectric signal is created
in response that quickly dies away to...
+

change

OFF

ON

-

0

1

2
Seconds

3

4
Ions in the fluids that bathe living bone
interact with the complex electric field
generated when the bone bends, causing
...
 Application

of orthodontic force by the
appliance will cause physical distortion
of the alveolar bone which is
accompan...
 Alterations

in blood flow associated with
pressure with in the periodontal
ligament

 Formation

and/or release of che...
Orthodontic force
Tissue trauma
Release of Ist messengers (PG)
(Extracellular signals are activated)
Conversion into intra...
Tissue reactions to orthodontic forces
were first described by Sandstedt in
1904,1905 and later by Oppenheim in
1930,1935,...
Light continuous force
Compression of blood vessels + PDL
Blood flow altered
Prostaglandins (Ist messenger) are released
S...
 The

bone was deposited on the tension
side of the tooth both with heavy and
light forces while on the pressure side
wit...
 With

the
application
of
heavy
forces, the periodontal tissues are
compressed leading to a cell free zone
called the hya...


In hyalinised areas ,resorption of the alveolus
takes place far from the cell free zone in the
bone marrow spaces and i...
 Cellular

activity is delayed in areas of
tension when compared to pressure
zones
 It takes 30 hours for increased cell...
 There

is inflammatory like breakdown and
rebuilding of fibrous elements in areas of
tension
 New unmineralised matrix ...
Orthodontic tooth movement consequent
to application of force is outcome of
complex chains of events ,eventually
leading t...
Contemporary Orthodontics Fourth
Edition – WILLIAM R PROFFIT
 Orthodontics Diagnosis and
Management of Malocclusion and
D...
THANK YOU !
BIOLOGY OF TOOTH MOVEMENT
BIOLOGY OF TOOTH MOVEMENT
Upcoming SlideShare
Loading in …5
×

BIOLOGY OF TOOTH MOVEMENT

11,162 views

Published on

ORTHODONTICS

Published in: Technology, Business
  • DOWNLOAD FULL BOOKS, INTO AVAILABLE FORMAT ......................................................................................................................... ......................................................................................................................... 1.DOWNLOAD FULL. PDF EBOOK here { https://tinyurl.com/y6a5rkg5 } ......................................................................................................................... 1.DOWNLOAD FULL. EPUB Ebook here { https://tinyurl.com/y6a5rkg5 } ......................................................................................................................... 1.DOWNLOAD FULL. doc Ebook here { https://tinyurl.com/y6a5rkg5 } ......................................................................................................................... 1.DOWNLOAD FULL. PDF EBOOK here { https://tinyurl.com/y6a5rkg5 } ......................................................................................................................... 1.DOWNLOAD FULL. EPUB Ebook here { https://tinyurl.com/y6a5rkg5 } ......................................................................................................................... 1.DOWNLOAD FULL. doc Ebook here { https://tinyurl.com/y6a5rkg5 } ......................................................................................................................... ......................................................................................................................... ......................................................................................................................... .............. Browse by Genre Available eBooks ......................................................................................................................... Art, Biography, Business, Chick Lit, Children's, Christian, Classics, Comics, Contemporary, Cookbooks, Crime, Ebooks, Fantasy, Fiction, Graphic Novels, Historical Fiction, History, Horror, Humor And Comedy, Manga, Memoir, Music, Mystery, Non Fiction, Paranormal, Philosophy, Poetry, Psychology, Religion, Romance, Science, Science Fiction, Self Help, Suspense, Spirituality, Sports, Thriller, Travel, Young Adult,
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • great .
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here

BIOLOGY OF TOOTH MOVEMENT

  1. 1. YASMIN MOIDIN 2008 Batch Al Azhar Dental College Thodupuzha
  2. 2. Orthodontic tooth movement (OTM) is a complex biomechanical process which is initiated by the clinician with the application of a force. The applied force moves the tooth beyond its range of physiologic tooth movement.
  3. 3.  Several factors affect and modify the nature and amount of orthodontic tooth movement. The most significant mechanical factors are: magnitude, direction and nature of the force. The inherent biological factors include bone density, age of the person, systemic health, hormones and factors that influence the bone turnover.
  4. 4. Physiologic tooth movement designates primarily the slight tipping of the functioning tooth in its socket and secondarily,the changes in tooth position that occur in young persons during and after tooth eruption.It is of three types: 1. Movement during mastication 2. Eruption of tooth 3. Tooth migration
  5. 5.  Tooth movement during masticatory function depends upon the location of neutral axis of the functioning tooth.  Neutral axis is located between the middle and apical regions of the roots in an adult tooth.  For younger persons,the neutral axis is either located in the marginal region or closer to the middle of the root ,if the root is fully developed.
  6. 6.  During chewing , the teeth tips slightly around the neutral axis as fulcrum.  Tooth is displaced because of bending of the alveolar process  Movement during mastication is transient. Once the occlusal load is removed, it reverts back to normal position
  7. 7.  Different teeth move in different directions during eruption  During eruption, upper molar teeth move mainly in mesial direction  Lower molar teeth show variations in direction of movement. Sometimes even a distal direction of movement is observed  Premolars sometimes show lingual movement during eruption
  8. 8.  Migration of teeth is a slow tooth movement  Direction of movement is usually mesial and occlusal  This corresponds to the adult equilibrium stage of tooth eruption  These movements take place to compensate interproximal attrition and occlusal wear
  9. 9. Each tooth is attached to and separated from the adjacent alveolar bone by a heavy collagenous supporting structure , the periodontal ligament (PDL). The width of the PDL is approximately 0.5mm.
  10. 10. 1. 2. 3. Collagen fibres Cellular elements Tissue fluids
  11. 11.  The major component of the PDL is a network of parallel collagenous fibers, inserting into cementum of the root surface on one side and into a relatively dense bony plate, the lamina dura,on the other side
  12. 12.  These supporting fibers run at an angle, attaching farther apically on the tooth than on the adjacent alveolar bone  This arrangement resists the displacement of the tooth expected during normal function
  13. 13.  The principle cellular elements in the PDL are undifferentiated mesenchymal cells and their progeny in the form of fibroblasts and osteoblasts
  14. 14.  Nerve endings are found within the ligament, both the unmyelinated free endings associated with perception of pain and the more complex receptors associated with pressure and positional information
  15. 15.  The PDL space is filled with fluid and is derived from the vascular system  Tissue fluids acts as a shock absorber
  16. 16. During masticatory function, the teeth and periodontal structures are subjected to intermittent heavy forces. Tooth contact lasts for one second or less, forces are heavy and tooth is subjected to heavy loads, quick displacement of the tooth within the PDL space is prevented by the incompressible tissue fluid and the force is transmitted to the alveolar bone ,which bends in response and formation of piezoelectric signals.
  17. 17. . Pain is normally felt after 3 to 5 seconds of heavy force application ,indicating that the fluids are expressed and crushing pressure is applied against the PDL in this amount of time. The resistance provided by tissue fluids allows normal mastication with its force applications of 1 second or less, to occur with out pain. Orthodontic tooth movement is made possible by application of prolonged forces.
  18. 18. TIME (SECONDS) EVENT LESS THAN 1 PDL fluid incompressible, alveolar bone bends, piezoelectric signal generated 1-2 PDL fluid expressed, tooth moves with in PDL space 3–5 PDL fluid squeezed out, tissues compressed;immediate pain if pressure is heavy
  19. 19. The phenomenon of tooth eruption makes it plain that forces generated within the PDL itself can produce tooth movement  The eruption mechanism appears to depend on metabolic events with in the PDL including but perhaps not limited to formation, cross-linkage and maturational shortening of collagen fibres.and it continues at a reduced rate into adult life 
  20. 20.  This mechanism also indicates active stabilization of the teeth against prolonged forces of light magnitude  Active stabilization implies a threshold for orthodontic force
  21. 21. 1. 2. Two major theories are: The bioelectric theory The pressure-tension theory
  22. 22. The bioelectric theory relates tooth movement at least in part to changes in bone metabolism controlled by the electric signals that are produced when alveolar bone flexes and bends. This bending and flexing generates electric signals that alter the metabolism of bone.
  23. 23. 1. PIEZOELECTRICITY 2. STREAMING POTENTIAL 3. BIOELECTRIC POTENTIAL
  24. 24. It is a phenomenon observed in crystalline materials in which deformation of a crystal structure produces a flow of electric current as electrons from one part of the crystal lattice are displaced to another. Bone and collagen and stress generated potentials in dried bone specimens have piezoelectricity
  25. 25. 1. 2. Quick decay rate:- When a force is applied a piezoelectric signal is created in response that quickly dies away to zero even though the force is maintained The production of an equivalent signal, opposite in direction when the force is released
  26. 26. + change OFF ON - 0 1 2 Seconds 3 4
  27. 27. Ions in the fluids that bathe living bone interact with the complex electric field generated when the bone bends, causing temperature changes as well as electric signals. The small voltages that are observed are called streaming potential.
  28. 28.  Application of orthodontic force by the appliance will cause physical distortion of the alveolar bone which is accompanied by bending of bone . Bone which is deformed by stress becomes electrically charged  Concave surfaces take a negative polarity and convex surfaces a positive polarity
  29. 29.  Alterations in blood flow associated with pressure with in the periodontal ligament  Formation and/or release of chemical messengers  Activation of cells
  30. 30. Orthodontic force Tissue trauma Release of Ist messengers (PG) (Extracellular signals are activated) Conversion into intracellular signals by 2 pathways Synthesis of cAMP IInd messengers Protein kinase enzymes within the cell Cellular changes Remodeling of bone Activation of Ca++ IIIrd messengers
  31. 31. Tissue reactions to orthodontic forces were first described by Sandstedt in 1904,1905 and later by Oppenheim in 1930,1935,1936
  32. 32. Light continuous force Compression of blood vessels + PDL Blood flow altered Prostaglandins (Ist messenger) are released Synthesis of cyclic AMP activation of Ca++ Metabolic activity Activation of osteoclasts
  33. 33.  The bone was deposited on the tension side of the tooth both with heavy and light forces while on the pressure side with light forces alveolar bone was resorbed directly by multinucleated osteoclast cells called frontal resorption or direct resorption
  34. 34.  With the application of heavy forces, the periodontal tissues are compressed leading to a cell free zone called the hyalinised tissue, which occurs due to thrombosis of vessels and cell death. on histologic sections, this zone resembles hyaline connective tissue and the process is called hyalinisation  The ideal orthodontic force should not exceed the capillary pulse pressure ,which is about 20-26gm/cm2
  35. 35.  In hyalinised areas ,resorption of the alveolus takes place far from the cell free zone in the bone marrow spaces and is called undermining resorption or rear resorption Tooth movement is delayed because of hyalinization and undermining resorption and the reasons are : differentiation and activation of osteoclasts from marrow space take more time  the thickness of bone to be removed from the underside is more 
  36. 36.  Cellular activity is delayed in areas of tension when compared to pressure zones  It takes 30 hours for increased cellular activity to be seen in tension zone  The stretched periodontal fibers are reconstructed by changes of the original fibrils  Macrophages are found in great numbers in tension zone
  37. 37.  There is inflammatory like breakdown and rebuilding of fibrous elements in areas of tension  New unmineralised matrix is laid down around the parts of the fibers that are close to the alveolar wall  After sometime ,osteoid is laid on the whole of the alveolar wall on the tension side  Osteoblasts synthesize the osteoid ,subsequently mineralization of osteoid takes place  Rate of bone deposition is about 30micro meter/day
  38. 38. Orthodontic tooth movement consequent to application of force is outcome of complex chains of events ,eventually leading to bone resorption and bone formation
  39. 39. Contemporary Orthodontics Fourth Edition – WILLIAM R PROFFIT  Orthodontics Diagnosis and Management of Malocclusion and Dentofacial Deformities OM PRAKASH KHARBANDA  Orthodontics – Exam Preparatory Manual for Undergraduates Second Edition – SRIDHAR PREM KUMAR 
  40. 40. THANK YOU !

×