3. MAGNETS IN ORTHODONTICS
PRESENTED BY:
MD. ISHTIAQ HASAN,
FCPS-II TRAINEE,
DEPT. OF ORTHODONTICS, DDCH
SUPERVISOR:
PROF. DR. MD. ZAKIR HOSSAIN
BDS, PHD(JAPAN)
PROF. & HEAD,
DEPT. OF ORTHODONTICS,
DDCH.
4. Magnets , at first used in
dentistry to aid in retention of
dental prosthesis in 1953.
In 1978, Dr. Blechman used
magnet in orthodontic tooth
movement.
4
5. TYPES OF MAGNETS
Platinum-cobalt (pt-Co)
Aluminium-nickel-Cobalt (Al-Ni_Co)
Ferrite
Chromium-Cobalt Iron
Samarium-Cobalt n(SmCo)
Neodymium-Iron-Boron (Nd2Fe14B)
6. ADVANTAGES OF MAGNETIC FORCE
OVER CONVENTIONAL FORCE SYSTEM
Constant force , no force decay over time
Less patient discomfort
Force system frictionless
Better directional control
Rapid tooth movement , Less treatment
duration
Minimum appliance adjustment
Less chair side time
Can exert their force through mucosa and bone
Remove need for elastics and springs
8. SYSTEMIC EFFECTS OF
MAGNET
Increase proliferation of fibroblast in
presence of magnet
Reversible epithelial thinning in
contact with epithelium
Increase blood flow
Increase cell division
Increase cartilage matrix formation ,
woven bone formation and increase
proliferation in marrow bone.
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9. CLINICAL APPLICATION OF
MAGNETS
Magnets can be used for---------
Tooth movement
Retention
Relocation of impacted tooth
Maxillary expansion
Open bite
Distalization of molar
Functional appliance
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27. ADVANTAGES
• Magnets exert their force through buccal mucosa
and bone.
• In conventional procedure, there is a
communication between the impacted tooth &
oral environment through the wire & chance of
spread of infection & irritation of the lips with wire &
difficult to adjust & change the direction of force &
poor patient compliance.
• But in magnetic procedure , it is possible
to move tooth in all three plane of space by
altering the magnetic arm.
• Patient is able to maintain good oral hygiene.
.
27
28. • Reduce treatment time. The rate of
canine movement is 1.22 mm/28 days
& in conventional procedure , 0.63
mm/28 days . (Reff-AJO-DO
Volume1996 May 489-495)
• Easy for operator and patient because
fewer adjustments are needed.
• Attachments are less likely to dislodge.
• Less painful to patient
• Force level increase with tooth
movement 28
33. ADVANTAGES
• Activation of the appliance is not
needed.
• Less chair side time.
• Better oral hygiene.
• Magnets can be reused after
sterilization.
• Invisible closure of midline diastema
can be obtained by applying
magnets to the palatal surface of
teeth.
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35. EXTRUSION OF POSTERIOR
TEETH
• An acrylic bite plane should use. If bite is
very deep, the gap between the post teeth
with anterior bite plane should be more than
4 mm and magnets should be bonded to
the occlusal surfaces of post teeth.
• Tooth movement is rapid and about 2 mm in
one month.
• If the gap between post teeth and ant bite
plate is less than 4 mm , the magnets need
to be positioned on buccal surface.
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36. INTRUSION OF
ANT TEETH
For ugly gummy smile ,
intrusion of incisors is
indicated.
Bonding the magnets
on labial surface of
ant teeth.
Make a full coverage
occlusal splint with
bucco-lingual
extension containing
attracting magnets 2-
3 mm apical to the
magnets on the ant
teeth.
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39. ALIGNMENT OF IRREGULARLY
PLACED TEETH
• Malocclusion where one or more teeth
are misplaced , can be aligned by
bonding magnets on the labial surface
of the teeth & construct an acrylic
plate with magnets in appropriate
position
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40. TOOTH MOVEMENT
ALONG ARCH WIRE
Edgewise appliance is used.
But
Upper & lower 6 have 2 molar
tube.
Occlusal molar tube carry the
magnet.
Gingival tube is used for basal
arch wire.
U & L magnetic poles face
each other in attracting mode
in order to generate force to
move the upper canine
distally along the arch wire.
Anchorage is controlled in
traditional manner with the
base arch wire
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41. EARLY CLASS III TREATMENT
Aim of treatment---
• Stimulate of forward maxillary growth
• Maxillary expansion for correction of
cross bite
• Restriction in forward mandibular
growth
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44. EARLY CLASS III TREATMENT
• Appliance design-------
– Bonded upper plate & lower removable
plate is used ,each carrying two buccal
magnets.
– The lower magnets are placed more
anteriorly than the upper buccal magnets
, thus creating a forward force in the
maxilla & backward force in mandible.
– The upper bonded appliance containing
two repelling magnets in the palate for
expansion. Only one repelling magnet
can slide for activation. 44
46. CLASS-II MALOCCLUSION
TREATMENT
• The appliance is basically an upper &
lower removable acrylic plate carrying
attracting magnets in both buccal
segments.
• Magnets are placed distal to upper
canine & distal to lower first premolar.
• A 30° inclination of the occlusal
surface of magnet to its buccal
surface produce an oblige force to
correct cl-II malocclusion.
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47. IN CL-II DEEP BITE CASES
Reff:AJO-DO 1993 Mar(223-239)
47
48. IN CL-II OPEN BITE CASES
Reff:AJO-DO 1993 Mar(223-239)
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49. IN CL-II OPEN BITE CASES
• Two repelling magnets can be used
posteriorly to produce molar &
premolar intrusion with some distal
movement of maxilla while pushing
the mandible downward & forward. In
addition , a pair of attracting midline
magnets located at the retroincisal
area to achieve symmetry , align
upper and lower midline and prevent
lateral movement. 49
50. PAIN FREE AND MOBILITY FREE
ORTHODONTICS
• In American Journal of Orthodontics
1998 , Dr. Blechman told magnetic
orthodontics is pain free and mobility
free.
• Discomfort & pain is the leading cause
of poor compliance during
orthodontic treatment.
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51. PAIN FREE AND MOBILITY FREE
ORTHODONTICS
• Some degree of mobility also can be noted
during orthodontic treatment because
during this process , bone resorption rate
exceeds deposition rate. During chewing ,
this mobility also causes pain.
• Magnetic force generate rapid tooth
movement without root resorption &
periodontal disturbances. Treatment time is
shorter.
• The magnetic field is responsible for the
reduction of pain because it block the
sensory nerve pathway. It can block almost
80% of action potential.
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53. PAIN FREE AND MOBILITY FREE
ORTHODONTICS
• Magnetic field were used to accelerate
human fracture repair. It also promote bone
fragment revascularization with more
expansion of vessels.
• Some neurologists and sport physician use
magnet to treat pain for osteoarthritis &
sports injury. By applying specially designed
magnets , patient feel pain relief in 10
minutes & healing time is dramatically
shortened. Accelerated healing is due to
increased blood flow due to relaxation of
capillary wall.
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54. PAIN FREE AND MOBILITY FREE
ORTHODONTICS
• Magnetic orthodontics is mobility free
because here bone deposition is almost
equal to the rate of resorption.(Reff:AJO-DO
1998 Apr(379-383)
• Tooth movement causes increase stress that
induce increase body’s citric acid level.
Traditional appliances causes increase of
46% of normal citric acid level which is
significant. But magnetic force increase 22%
of normal citric acid level which is not
significant. 54
55. CONCLUSION
Magnets are used successfully for
tooth movement but they are not
routinely used.
Magnets and the magnetic force
system is better device for theoretical
& academic purpose. Not easily one
can practice in day-to-day life. Need
to be very thorough in magnetic
physics. Also they are expensive.
Thus the main & only idea of all these
discussion are to review the work of
various authors , to learn from them ,
enjoy them & to think different.
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