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2. INDIAN DENTAL ACADEMY
Leader in continuing dental education
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3.
The name clasp is derived from
a French word “UYPTAN” which
means to embrace. Clasps are
the retentive components of the
orthodontic appliances.
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4. RETENTION
:- is the
means whereby the
displacement of an
appliance is resisted.
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5. Why retention is needed ?
IF poor retention - difficulty to
wear-poor pt co-operation.
If the appliance is not seated
properly-the active components
may not function properly due to
continual movement of
appliance, breakage of springs
are liable.
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6.
In children the undercut may lie
just below the gingival margin,
and it is necessary to construct
the clasp so that it displaces the
gingival margin slightly.
It is important that the clasp
does not extend too far into an
undercut area.
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7. IDEAL REQUIREMENTS
Unobtrusive.
Not impinge.
Close contact to the tooth.
Usable in both deciduous and
permanent dentition.
Adequate retention.
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8. No active force on the anchor
tooth.
Rigid
Easy to fabricate and also
replace if needed.
Not interfere in the growth of
jaws and eruption of teeth.
Clasps should be at the center
of the buccal segment to ensure
stability of the appliance.
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10. MODE OF ACTION
Clasp engage onto the
undercuts (constricted areas on
the teeth.)
Two types of undercuts.
Buccal
/ Lingual Cervical
undercuts.
Mesial / Distal Proximal undercuts.
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12.
Circumferential clasp / C-Clasp /
3/4th Clasp.
To use the bucco-cervical
undercut.
2nd molar and canines.
Single retention arm.
1mm wire used in molars.
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17.
V.H. Jackson 1906
Jacksons Clasp / Full Clasp / U
Clasp.
Both bucco-cervical and
proximal undercuts.
0.7mm to 1mm.
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26.
Also called as MODIFIED
ZIMMERMANS CLASP.
Excellent retention by the single
arrowhead in the interproximal
area.
Open end towards the occlusal.
Can engage elastics.
0.7mm wire
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28. Advantages of triangular clasp
Easy to fabricate.
Excellent retention.
Pre fabricated available.
Elastics can be engaged.
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29. Disadvantages of triangular clasp
Not useful if adjacent tooth is
absent.
Used as secondary or additional
retention.
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31.
Action and location similar to
triangular clasp.
Prefabricated available. Can be
made by adding solder to end of
a wire.
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33. Advantages of BALL END CLASP
Easy to fabricate.
Single occlusal interference.
Less gingival irritation.
Easy to replace.
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34. Disadvantages of BALL END
CLASP
Short arm makes adjustment
difficult.
Can not be used for primary
retention.
Cannot be used in absence of
adjacent tooth.
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38. Advantages of SCHWARZ
CLASP
Reliable retention.
Does not interfere in posterior
occlusion.
More wire hence more flexible.
More easy to adjust.
Enhances eruption.
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39. Disadvantages of SCHWARZ
CLASP
Difficult to fabricate.
Needs special plier.
Irritates soft tissue.
Tends to separate teeth.
Is bulky hence less patient
compliance.
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41.
Crozat in 1920
Along with the u clasp a stright
wire is soldered on the base
(Cresent).
Strong retention is possible
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44.
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 posteriors
0.6mm anteriors.
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47. BRIDGE
Is 2/3rd the mesio dital 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.
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48. Arrowheads
They should lie in the disto- and
mesio buccal undercuts.
Shaped according to the curve of the
gum margins in the direction of the
interdental papilla.
Long enough to keep the bridge at a
proper distance.
Should not touch the adjacent teeth
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49. Tag arms
Closely fitted to the contact points,
down to the interdental embrasure.
Space between the tag arms and
palate for flow of acrylic.
No sharp bends.
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50. Advantages of ADAMS CLASP
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 variations are available.
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51. Disadvantages of ADAMS CLASP
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.
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