FIXED EXPANSION ORTHODONTIC APPLIANCES
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Introduction Expansion in arch has been one of the oldest means of creating space in the dental arches. • It is also one of the conservative method of gaining space. • It can also be used to correct the intermaxillary and dental arch relationships primarily in transverse direction. • It enables correction of crossbites early in treatment. www.indiandentalacademy.com
History • Narrow maxilla was recognized for thousand years and Hippocrates has also refered to it. • In 1860 Emerson C.Angell placed a screw between maxillary premolar of a girl aged 14 yrs and wider her arch in two weeks. • In 1877 Walter coffin demonstrated the expansion of the maxillary arch using spring which caused separation of the mid palatal suture in children. www.indiandentalacademy.com
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Pfaff, in 1929 described improved nasal function after maxillary expansion. Haas, in 1960 reported increased nasal width,gain in arch and lowering of mandible with bite opening.
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CLASSIFICATION 1.Fixed or Removable 2.Fixed • Rapid maxillary expansion • Slow maxillary expansion
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Rapid maxillary expansion appliances
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Banded appliances
Derischweiler type Haas type Beiderman type Issacson type Arnold type
Bonded RME appliance
Full coverage bonded RME appliance
Removable RME appliance
Hilger’s palatal expander www.indiandentalacademy.com
Rapid maxillary appliances Indications •Marked narrowing of the arches •Unilateral or bilateral cross bite •Mandibular prognathism with reduced anterior development of the maxillary base •Steep palate with septal deviation and mouth breathing due to enlarged adenoids •Cleft lip and palate •Mild arch length to tooth material deficiency.(1mm of expansion in post = 0.7 mm increase in arch perimeter) www.indiandentalacademy.com
Contraindications
No true contraindications
Anterior open bite cases
High FMA, convex profile cases
Skeletal asymmetry of maxilla and mandible with severe anteroposterior discrepancy.
Older age group due to ossification of sutures
Patients on dilantin therapy
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Appliance design criteria Rigidity Tooth utilization maximum Economy Hygiene
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Banded appliances Derischweiler type: •Tags are soldered to the palatal aspects of bands to provide attachments for the acrylic. •Acrylic also extends to the palatal of all non banded teeth except incisors
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Haas type: • A length of the wire is soldered along the palatal aspects of the bands. • Free ends turned back and embedded in acrylic. • A screw is incorporated. • Banding difficult on malposed teeth. • Banding and cementation difficult on deciduous teeth. Indication • In late mixed and early permanent dentitions. www.indiandentalacademy.com
Beiderman type
This design also called hygienic palatal expander. Requires a special screw. These have extensions in heavy gauge wire which are soldered to the palatal aspects of bands. Acrylic free palate, so no food entrapment, mucosal irritation and no ulceration.
Indication Deciduous and early mixed dentition. www.indiandentalacademy.com
Issacson type •This appliance has a special spring loaded screw called a minne expander •It is soldered directly to the bands •No acrylic is used •Easy to fabricate
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Arnold appliance
Coil spring expander is attached by means of vertical half tubes on the molar bands.
Tubes cosist of coil springs
It expands the arch by lingual pressures,using coil springs for power
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Bonded appliance
Raymond Howe in 1982 developed this appliance Clears the palate from acrylic No banding needed- can be used on malposed teeth where parallel path of insertion is not possible Less error prone as bands don’t have to be placed in impression Easy to make on deciduous teeth.
Wire framework
Completed appliance On model
Acrylic-lined bondable RME appliance
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Full coverage bonded RME appliance
Developed by John Spolyar in 1984 Solely for tooth borne anchorage Spider type expansion screw is placed as anteriorly as possible Acrylic free palate No bands present Difficult to remove
Appliance showing Anatomy surface
Extent of occlusal coverage www.indiandentalacademy.com
Appliance on Study model
Removable RPE appliance
Developed by Vel Ivanovski in 1985 Used for correction of crossbite and expansion of both maxilla and mandible No bands, clasps and easy to fabricate 2 mm thick acrylic sheet are moulded on the models with screw stabilized on the models using biostar In a single appliance extension are given to the lingual of mandibular teeth for simultaneous expansion Separate upper and lower appliances can also be made
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Hilgers palatal expander – PEND-EX Appliance •Consist of two molar bands with soldered horizontal helices and an acrylic plate •With embedded jackscrew •Anterior extension of the wire serve as the bonded occlusal rest •Helices serve to rotate and distalize the upper molar •Jack screw produces orthopedic midpalatal disjunction www.indiandentalacademy.com
Activation
Use head gear plier to twist the molar bands distally to incorporate twice the the amount of rotation needed Place the lingual bend in the vertical portion of the wire that extends out of the acrylic. Hold the helical with the head gear plier and bend the appliance towards palate to place a minor tip back force on the molars
Advantages
The appliance is able to make changes in arch width and form Distal rotation of upper molars Creates room for canine eruption Anchors the molars during upper retraction www.indiandentalacademy.com
Regime of screw rotation Upto age of 15 years : the turn 180 degree is given as 90 degree in the morning and 90 degree in the evening. 15-20 years : overall rotation of 180 is possible by splitting the rotation into 4 turns of 45 degree each with approx equal time lapse between them. Age over 20 years : 45 degree turn in the morning and 45 in the night initially Over 25 years: surgical separation may be required.
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Zimring and Isaacson in 1965 : ď Ž
Young or growing patients: two turns each day for the first 4-5 days and one turn each day for remainder of rme treatment.
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Adult patients: two turns each day for the first two days and one turn each day for the next 5-7 days and one turn each other day for the remainder of the RPE treatment.
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Effects of RPE
The separation of midpalatal suture is triangular in all three planes. The fulcrum of separation lies at varying distance from MPS depending on age. There is generally downward and forward movement of maxilla due to zygomatic buttressing.
Sagittal www.indiandentalacademy.com
The mandible also rotates downward and backward exaggerating retrognathia.
The alveolar bone bends laterally and the palatine bones inferiorly increasing nasal cavity.
Splaying of hamular processes of the sphenoid bone is seen.
As the maxilla moves forward and downward due to loosening of the circummaxillary sutures, maxillary protraction may be applied with face mask or reverse headgear.
Arch perimeter increase is 0.7 times the intermolar width increase.
Palatal depth is increased due to overeruption of posterior teeth.
Mandibular arch length expansion is also seen in RPE: upto 1.1mm increase in intercanine width and 2.5mm in intermolar width. www.indiandentalacademy.com
Clinical management of RPE patient
Pain is not usually present in juveniles, adults may complain.
Pain is usually at the time of activation.
Midline diastema is most important proof of separation.
Petechie may be present on the palatal mucosa which resolves in a week or two.
Occlusal interference are seen.
Patient report inability to masticate from back teeth.
Overexpansion is advised till lingual cusps of upper molars occlude with lingual inclines of lower buccal cusps. www.indiandentalacademy.com
Slow palatal expansion Fixed Appliances used
W arch Quad helix Ni-Ti arch wires 3D Wilson appliance
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W- arch •A fixed type modification of coffin spring •First used by ricketts in cleft palate cases •Prefered in deciduous and mixed dentition where mild to moderate expansion is required
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Quad helix Introduced by dr. Robert Ricketts in 1975
Indications: •All cross bites needing upper arch expansion •Crowding cases needing mild expansion •Class II needing molar distal rotation •Class III with constricted maxillary arch •Tongue thrusting cases •Cleft lip and cleft palate cases www.indiandentalacademy.com
Activation A six week interval is observed before further activation Extra oral: 1mm each side in molar region and 1.5mm anteriorly Ricketts prescribes 500 gm of force to separate mps Intraoral: Triple beak plier is used Anterior bridge is bend by keeping single beak anteriorly for intermolar expansion 2nd and 3rd bend on palatal bridges for lateral arms.
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Activation
Can be opened anteriorly at the curve as well as at the posterior apices
Opened 3-4 mm wider that passive width
Expansion done at the rate of 2 mm per month
Unequal arm length can be kept in true unilateral crossbite cases
Over treatment is done
Can be kept as a retainer for 3-4 months
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Quad helix Introduced by dr. Robert Ricketts in 1975
Indications: •All cross bites needing upper arch expansion •Crowding cases needing mild expansion •Class II needing molar distal rotation •Class III with constricted maxillary arch •Tongue thrusting cases •Cleft lip and cleft palate cases www.indiandentalacademy.com
Activation A six week interval is observed before further activation Extra oral: 1mm each side in molar region and 1.5mm anteriorly Ricketts prescribes 500 gm of force to separate mps Intraoral: Triple beak plier is used Anterior bridge is bend by keeping single beak anteriorly for intermolar expansion 2nd and 3rd bend on palatal bridges for lateral arms.
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Ni Ti palatal expanders
Introduced by wendell arndt in 1993 A fixed – removable appliance Depends on shape memory and super elasticity of NiTi Transition temperature 94°F Continuous force levels between 230gms to 300 gms. Available in 8 intermolar widths; 26-47 mm 26-32mm width appliances are of softer wires for younger patients Freeze gel packs can be used to make appliance flexible for insertion www.indiandentalacademy.com
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