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.