Removable Orthodontic Removable Orthodontic Appliances For Tooth Movement pp

83 Pages·2009·1.34 MB·English

RReemmoovvaabbllee OOrrtthhooddoonnttiicc
Appppliances For Tooth Movement
DDrr.. ZZuuhhaaiirr MMuurrsshhiidd,, BBDDSS..,, OOrrtthhoo..
Cert. M.Phil.
CConsulltant andd AAssiistant PProffessor off
Orthodontics
E-Mail: [email protected]
Terminology
• Removable appliance
An appliance that is not fixed to teeth, but
ccaann bbee rreemmoovveedd bbyy tthhee ppaattiieenntt.
History and Development
• Victor Hugo Jackson (early 20th century)
Vulcanite bases &precious metals
• CCrroozzaatt uusseedd pprreecciioouuss mmeettaall ((ggoolldd)) ffoorr
expansion appliance
Classification Of ROA
• Active (produce tooth movement/growth
moddiiffiicatiion))
Mechanical appliances
Functional appliances (FA s.)
• Passive
RRetaiiners
Space maintainers
TTooootthh mmoovveemmeenntt wwiitthh rreemmoovvaabbllee
appppliances
• Tooth movement with removable
appliances almost always falls into one of
the followingg categgories:
• 1- Increase arch perimeter (arch expansion).
• 2- Reposiitiioniing off iinddiiviidduall teethh wiithhiin
the arch.
• 3- Intrusion or Extrusion of teeth.
AAccttiivvee PPllaatteess ffoorr AArrcchh EExxppaannssiioonn
.
-Anterior Expansion of maxillary incisors
-Transverse Expansion of the Arches.
-SSiimulltaneous AAnteriior andd posteriior
EExxppaannssiioonn
Active Plate for Arch Expansion
Active pplate are most useful when a few
millimeters of space are needed (1.5-2 mm side).
TThhee aaccttiivvee eelleemmeenntt ooff eexxppaannssiioonn ppllaattee iiss aa
jackscrew placed so that it holds the parts of the
ppllaattee ttooggeetthheerr.
The screw produces a heavy force that decays
rapidly. Most screws open 1 mm per complete
rreevvoolluuttiioonn,, ssoo ssiinnggllee qquuaarrtteerr ttuurrnn pprroodduucceess 00..2255
mm of tooth movement.
We should not exceed 1 mm pper month
i.e. one ¼ turn/week and not more than two
¼¼ ¼¼ ppeerr wweeeekk aanndd iitt sshhoouulldd bbee aaccttiivvaatteedd
while the appliance is worn (inside the
mouth)
Anterior expansion of maxillary incisors.
The simplest uses of an active plate is to correct
a maxillary anterior crossbite.
PPoosstteerriioorr bbiitteeppllaannee iiss nneecceessssaarryy iinn aadduulltt ttoo
allow clearance for the upper incisor to move
oouutt ooff ccrroossssbbiittee ((½½ ccrroowwnn oorr mmoorree iiss ccoovveerreedd)).
TTrraannssvveerrssee EExxppaannssiioonn ooff tthhee AArrcchheess
AActiive pllate splliit iin miiddlliine wiillll expandd
constricted maxillary arch almost totally by
tipping the posterior teeth buccally Not by
ooppeeningg midd-pplatal ssuutuuree.. Theereefooree thiss
appliance is not indicated for skeletal crossbites
oorr ddeennttaall eexxppaannssiioonn ffoorr mmoorree tthhaann 22 mmmm ppeerr ssiiddee.