upper removable appliance (ura) group 1. removable appliances work by simple tipping movements of...

UPPER REMOVABLE APPLIANCE (URA)

GROUP 1

Removable appliances

Work by simple tipping movements of the Work by simple tipping movements of the crowns of the teeth about a fulcrum close to the crowns of the teeth about a fulcrum close to the

middle of the toothmiddle of the toothalso allow differential eruption of teeth, for also allow differential eruption of teeth, for

example by using bite planes. example by using bite planes. They differ from fixed appliances, which are They differ from fixed appliances, which are capable of complex movements of multiple capable of complex movements of multiple

teeth, including bodily movement, root torque teeth, including bodily movement, root torque and rotation.and rotation.

Classification

Function/Role• Interceptive treatment during mixed dentition

– Eg : crossbite correction space maintainer expansion to reopen space

• Facilitate of distal movement of the molars using headgear.• As an adjunct to fixed appliance tx.

– Eg : anterior bite planes for overbite reduction• Maxillary restrain

– Eg: maxillary intrusion splint

• Assess motivation and compliance before more complex tx.

INDICATIONS &CONTRAINDICATIONS

INDICATIONS• Growth modification during

mixed dentition• Limited (tipping) tooth

movements desired (arch expansion, individual tooth mal position).

• Retention following orthodontic treatment

• Adjunct to fixed orthodontic appliances,

• Interfere with (or prevent the development of) abnormal orofacial habits

CONTRAINDICATIONS• Severe skeletal discrepancy• Upper and lower arch

correlate treatment• Severe rotation• Bodily movement needed• Vertical discrepancy• Severe crowding• Very dense bone

ADVANTAGES & DISADVANTAGESADVANTAGES

• Removable for social function• Suitable for simple

malocclusion• Smaller anchorage

requirement• Uncompromised oral hygiene• Short chair-side time• Ease of adjustment• Require less training for

management

DISADVANTAGES

• Dependent on patient compliance

• Less precise control of tooth movement

• Unable to perform complex tooth movement

• Difficult to control space closure• Fewer tooth movement• More difficult to correct

rotation• Affect speech• Retention poor in lower arch• Prone to breakage and loss

ACTIVE COMPONENTS

•Springs•Screws•Elastics

Z-spring• Stainless steel wire• 0.5mm diameter• Function:

-proclination of 1 or 2 incisors-to correct mild rotation if only 1 helix is activated

T-spring

• For incisor, 0.5mm diameter stainless steel(SS) wire• For premolar, 0.6mm diameter SS wire• Function:

-for proclination of incisors or premolar

Finger spring

• For incisor, 0.5mm SS wire• For canine and premolar, 0.6mm SS wire• Function:

-for mesial or distal movement

Labial bow

• 0.7mm diameter SS wire• Function:

-for retraction of anterior teeth

Split labial bow

• 0.7mm diameter SS wire• Function:

-retraction of anterior teeth-to close diastema

Robert retractor

• 0.5mm diameter SS with sleeve• Function:

-retraction of anterior teeth

Buccal canine retractor

• 0.7mm diameter SS wire• Function:

-palatal and distal movement of mesially angulated canine

Coffin spring

• 1.25mm diameter SS wire• Function:

-transverse expansion-buccal crossbite correction

Screw

• Function:-for expansion of arch-for distalization of molar teeth

• 1 turn / week = 0.25mm(1/4 turn)

Elastics • Rubber or latex rings• Function:

-extra-oral traction-inter-maxillary traction

• However, it depends largely on the patient cooperation

RETENTIVE COMPONENTS

• Clasps– Adam’s clasp– C-clasp

(Circumferential clasp)– Lingual extension clasp– Ball clasp

Adam’s Clasp

• The most useful clasp in removable appliances.

• It is designed to engage the MB, DB undercuts of posterior teeth.

• Advantage, it does not separate teeth and has excellent retention.

Adam’s Clasp fabrication

• Components of Adam’s Clasp

• 1- Arrow heads• 2- Bridge• 3- Tags• 4- Retentive parts

• It is made of 0.7 mm diameter hard St. round wire

Adam’s Clasp

• Design modifications

Long bridgeOne arrow head Solder a HG tube to the bridgeSolder hook to he bridge

Adam’s clasp adjustment

• 1. To tighten/loosen: Adjust the arrowhead to grip the undercut of the tooth. Hold arrowhead with pliers at A and bend using finger inwards in direction shown.

• 2. To adjust the height: Hold adams clasp wire the wire exits the acrlyic at pint B and bend the wire up or down to adjust verical position of arrowhead.

Circumferential clasp

• Circumferential clasp– Useful for second molars and canines– Easier to keep it out from occlusal contact– It is only supportive, not as retentive as Adam’s

clasp– It can be adequate for a retainer, but not for an

active appliance

Ball Clasp

• Ball Clasp– It like Adam, extends across the embrasure– Uses buccal undercuts for retention– Easy to fabricate– It is stiff that could not be extended deep into the

undercuts

Lingual Extension Clasp

• Lingual Extension Clasp– It works only from the lingual aspect without crossing the

occlusal surface or embrasures– Short loop of (0.4 mm) wire– Can be placed in the first molar second premolar lingual

embrasure– Difficult to adjust– Break easily– May cause tissue irritation– Can separate teeth if active– Can be used for retainers, – not for active appliance

ANCHORAGE

Resistance to unwanted tooth movementBY

equal in magnitude and opposite in direction

BASEPLATE• It must be:

-hold components-clear acrylic = heat cure, cold cure polymethyl-methacrylate, autoresin-comfortable-good fit-can be active as additional functions-act as bite plane

References • http://www.retainerlab.com/Pages/Springs.htm• http://universal-dental-techniques.com• http://www.intelligentdental.com/2011/10/02/agapbetween-your-

upper-front-teeth/• http://dentallecnotes.blogspot.com/2011/10/note-on-active-

components-of-removable.html• http://o-atlas.de/eng/kapitel5_156.php• http://askanorthodontist.com/braces/what-do-the-elastic-rubber-

bands-on-braces-do/• Lecture by Dr. Norzakiah(principles of removable appliance

therapy-part 1)• Lecture by Dr. Fitri Octavianti(types of orthodontic appliances)