clasps 1 / orthodontic courses by indian dental academy

CLASPS

INDIAN DENTAL ACADEMY

Leader in continuing dental education www.indiandentalacademy.com

www.indiandentalacademy.com

Clasps are the retentive components of the orthodontic appliances.

INTRODUCTIONINTRODUCTION

The unit of removable orthodontic appliance that holds the appliancein position and is called clasp.


There are many types of clasps.There are many types of clasps.

1.’ C ’ clasp2.Full clasp or Jackson’s clasp3.Triangular clasp4.Adam’s clasp and their modifications5.Schwarz clasp6.South end clasp7.Duyzing clasp8.Ball end clasp9.Crozat clasp


IDEAL REQUIREMENTS

• Unobtrusive.Unobtrusive.• Not impinge.Not impinge.• Close contact to the tooth.Close contact to the tooth.• Usable in both deciduous Usable in both deciduous

and permanent dentition.and permanent dentition.• Adequate retention.Adequate retention.


• No active force on the anchor tooth.No active force on the anchor tooth.• RigidRigid• Easy to fabricate and also replace if Easy to fabricate and also replace if

needed.needed.• Not interfere in the growth of jaws Not interfere in the growth of jaws

and eruption of teeth.and eruption of teeth.


USES

To secure the appliance in positionTo secure the appliance in positionTo prevent rolling of appliances To prevent rolling of appliances To resist forces of displacementTo resist forces of displacementTo provide retention & anchorageTo provide retention & anchorageFor engaging elasticsFor engaging elastics


MODE OF ACTION OF CLASPSClasp engage onto the undercuts Clasp engage onto the undercuts (constricted areas on the teeth.)(constricted areas on the teeth.)

Two types of undercuts.Two types of undercuts.Buccal / Lingual Cervical undercuts.Buccal / Lingual Cervical undercuts.Mesial / Distal Proximal undercuts.Mesial / Distal Proximal undercuts.


CIRCUMFERENTIAL CLASP


Circumferential clasp / C-Clasp / 3/4th Clasp.

It uses the bucco-cervical undercut.

Single retention arm.

1mm wire used in molars.


Advantages

Good retention.Easy to fabricate.Single occlusal crossover wire.Easy to replace.


Disadvantages

Not on semi-erupted tooth.Decalcification of cervical margin.Gingival irritation.Plaque accumulation enhanced.Easily distort.


JACKSONS CLASP


Jackson 1906

Jacksons Clasp / Full Clasp / U Clasp.

Both bucco-cervical and proximal undercuts.


Advantages

Simple designAdequate retention.


Disadvantages

Not useful in partially erupted teeth.Not useful in partially erupted teeth.Difficult to adjust.Difficult to adjust.Not on unfavorably inclined tooth.Not on unfavorably inclined tooth.


SOUTHEND CLASP


Most common for anterior anchorage.Single arrowhead between Central

Incisors with wire following the gingival margin.


TRIANGULAR CLASP


Excellent retention by the single arrowhead in the interproximal area.

Free end towards distal to facilitate the engagement of elastics.


Advantages

Easy to fabricate.Excellent retention.Pre fabricated available.Elastics can be engaged.


Disadvantages

Not useful if adjacent tooth is absent.Used as secondary / additional retention.


BALL END CLASP


Action and location similar to triangular clasp.

Pre fabricated available. Can be made by adding solder to end of a wire.


Advantages

Easy to fabricate.Single occlusal interference.Less gingival irritation.Easy to replace.


Disadvantages

Short arm makes adjustment difficult.Cannot be used for primary retention.Cannot be used in absence of adjacent

tooth.


SCHWARZ CLASP


Also called as ARROWHEAD CLASP.

Mesial and distal undercuts of the teeth.


Advantages

Reliable retention.Does not interfere in posterior occlusion.More length of wire hence more flexible.More easy to adjust.Enhances eruption.


Disadvantages

Difficult to fabricate.Needs special plier.Irritates soft tissue.Tends to separate teeth.Is bulky hence less patient compliance.


CROZAT CLASP


Along with the u clasp another curved wire is soldered on the base.

Strong retention is possible


ADAMS CLASP


Adams clasp / modified arrowhead clasp / liverpool clasp / universal clasp.

C. PHILIPS ADAMS in May 1950.

Most widely used clasp.

Distobuccal and mesiobuccal undercuts.

Does not separate teeth like a arrowhead clasp.

0.7mm posteriors0.6mm anteriors.


Parts

BRIDGE2 ARROWHEADS2 TAG ARMS


BRIDGE Is 2/3rd the mesio-distal width of the

tooth, or slightly less then the distance between mesiobuccal and distobuccal undercuts, or length should be equal to the intercuspal distance.

Is 1-2mm away from the buccal surface of the tooth.

Is at 45o to the buccal surface of the tooth.

Should be straight.


Arrowheads

They should lie in the disto and mesio buccal undercuts.

Shaped according to the curve of the gum margins into the interdental papilla.

Long enough to keep the bridge at a proper distance.

Should not touch the adjacent teeth


Tag arms

Closely fitted to the contact points, down to the interdental embrassure.

Space between the tag arms and palate for flow of acrylic.

No sharp bends.


Advantages

Small,neat and unobtrusive. Any tooth. Both deciduous and permanent dentition. Even on semi erupted tooth. No specialized pliers required. Can be modified as needed. No. of modifications are available.


Disadvantages

Unwanted palatal tipping if gets activated. May lead to elongation of tooth if is fitting

tightly. Can be repaired only if fractured through the

arrowheads. Cannot be given on proclined anteriors.


Fabrication


MODIFICATIONSOF ADAMS CLASP


Anterior Adams

0.6mm Also called double clasp.


With distal extension/ traction hook To engage elastics Not given if sulcus is shallow.

Distal extension


With a soldered hook


With a soldered tube


With a single arrowhead


With accessory arrowhead


For more details please visit www.indiandentalacademy.com


clasps 1 / orthodontic courses by indian dental academy

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