The success of removable orthodontic appliance mainly depends upon good retention of the appliance. Adequate retention of a removable orthodontic appliance is achieved by incorporating certain wire components, called clasp, which engages the undercuts on the teeth. Clasps are the retentive components of removable orthodontic appliances. There are various designs of clasps advocated for various clinical situations. This article presents an overview of various clasp designs with advantages and disadvantages of each type and their uses in particular clinical situations. DOI: http://dx.doi.org/10.3126/jonmc.v3i1.10046 Journal of Nobel Medical College Vol.3(1) 2014; 1-9
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Review Article Orthodontics
Journal of Nobel Medical College Vol. 3, No.1 Issue 5 16
CLASPS IN REMOVABLE ORTHODONTICS
Mustapha Mansuri, Varun Pratap Singh
Abstract
The success of removable orthodontic appliance mainly depends upon good retention of the
appliance. Adequate retention of a removable orthodontic appliance is achieved by incorporating
certain wire components, called clasp, which engages the undercuts on the teeth. Clasps are the
retentive components of removable orthodontic appliances. There are various designs of clasps
advocated for various clinical situations. This article presents an overview of various clasp designs
with advantages and disadvantages of each type and their uses in particular clinical situations.
Key words: Clasp, Removable orthodontic appliance, Retention.
Introduction
Clasps are wire components that aid in
retention of a removable appliance. [1] These are
the retentive components that aid in keeping
the appliance in place and resist displacement
of the appliance.
Mode of action
Clasps act by engaging constricted areas of the
teeth, called undercuts. There are two types of
undercuts found in natural dentition.
1. Buccal and Lingual cervical undercuts
2. Mesial and Distal proximal undercuts
The mesial and distal undercuts of the teeth
begin below the contact points. [2] These
undercuts are accessible very soon after a tooth
has erupted. The buccal and lingual undercuts
are much less extensive and are not accessible
until the teeth are fully erupted. Thus, a clasp
that makes use of mesial and distal undercuts
is more useful and more efficient than a clasp
which makes use of buccal and lingual
undercuts.
An ideal clasp should [1] :-
Offer adequate retention
Permit usage in both fully and partially
erupted teeth
Be passive
Be easy to fabricate
Not impinge on the soft tissue
Not interfere with normal occlusion
Different clasps are [1] [3]
1. 'C' clasp
2. Jackson's clasp
3. Arrowhead clasp
4. Adam's clasp
5. Delta clasp
6. Southend clasp
7. Triangular clasp
8. Ball-end clasp
9. Double ball-end clasp
10. Schwarz clasp
11. Crozat clasp
12. Duyzing clasp
13. Eyelet clasp
14. Plint clasp
15. Visick clasp
1. 'C' clasp
It is also known as three-quarter clasp (3/4
clasp) or Circumferential clasp. They are very
simple clasp and engage bucco-cervical
undercut.
Review Article Orthodontics
Journal of Nobel Medical College Vol. 3, No.1 Issue 5 26
Fig. Circumferential Clasp
Advantages:-
Easy to construct
Simple design
Prevent mesial migration of tooth
Disadvantage:-
It can't be used in partially erupted
teeth.
2. Jackson's clasp
It is also known as Full clasp or 'U' clasp. It
was introduced by V H Jackson in 1906.This
clasp makes use of bucco-cervical undercut
and also the mesial and distal proximal
undercuts.
Fig. Jackson's clasp
Advantages:-
Simple to construct
Offers adequate retention
Disadvantage:-
Inadequate retention in partially erupted
teeth.
3. Arrowhead Clasp
This clasp was introduced by A M Schwarz in
1956. This clasp makes use of mesial and distal
undercuts. This clasp is made using half round
or round stainless steel wire of 0.7 mm
diameter. This clasp is made by use of a special
plier called 'Tischler's plier'.
Fig. Arrowhead clasp
Advantages:-
Good retention on partially erupted tooth
Eruption of tooth is not hampered
Disadvantages:-
Occupies large amount of buccal surface
Requires special plier and adequate skill
for construction.
Continuous Arrowhead clasp
This clasp carries 4-6 arrow clasps. It is one
continuous wire with ends in acrylic mass.
Review Article Orthodontics
Journal of Nobel Medical College Vol. 3, No.1 Issue 5 36
Fig. Continuous arrowhead clasp
4. Adam's clasp
It is also known as Universal clasp or Modified
arrowhead clasp or Liverpool clasp. This clasp
was devised by C P Adam in 1948. This clasp
makes use of mesial and distal undercuts. This
is the most effective and most widely used
orthodontic clasp today. This clasp is
constructed using 0.7 mm hard round stainless
steel wire.
Fig. Adam's clasp
Advantages:-
This clasp is strong, simple and easily
constructed.
It can be used on any tooth (deciduous or
permanent, partially or fully erupted,
incisors or premolars or molars).
It is comfortable to wear and resistant to
breakage.
It is small and occupies minimum space.
It can be modified in a number of ways.
No specialized instrument is needed for
construction of clasp. Routinely used
Young's Universal plier or Adam's plier
can be used.
Parts of Adam's clasp
Two arrowheads
Bridge
Two retentive arms
Bridge- It should be straight and midway
between the occlusal surface and gingival
margin. It should be 2mm away from the tooth
surface and parallel to it. When viewed from
the side, the bridge should be at 45° angle to
tooth surface.
Arrowheads- should be parallel to each other
and should sit in the mesial and distal
undercuts.
Retentive arms- continue on the lingual or
palatal surface that get embedded into the
acrylic.
Modifications of Adam's clasp
4.1 Adam's clasp with single arrowhead
4.2 Adam's clasp with J hook
4.3 Adam's clasp with incorporated helix
4.4 Adam's clasp with additional arrowhead
4.5 Adam's clasp with soldered buccal tube
4.6 Adam's clasp with distal extension
4.7 Adam's clasp on incisors and premolars
4.8 Smart clasp:- A modified Adam's clasp
Review Article Orthodontics
Journal of Nobel Medical College Vol. 3, No.1 Issue 5 46
4.1 Adam's clasp with single arrowhead
This clasp consists of only single arrowhead
instead of two arrowheads. This clasp
combines characteristics of Adam's clasp and
'C' clasp. It is indicated in partially erupted
tooth where the single arrowhead engages the
mesial undercut and the bridge is modified to
encircle the tooth distally. The partially
erupted tooth is usually the last erupted molar.
Fig. Adam's clasp with single arrowhead
4.2 Adam's clasp with J hook
A 'J' shaped hook is soldered to the bridge of
the Adam's clasp directed gingivally with the
hook pointed distally. This hook is used to
engage elastics.
Fig. Adam's clasp with J hook
4.3 Adam's clasp with incorporated helix
A helix is incorporated into the bridge of the
Adam's clasp. This is also useful in engaging
elastics. This modification is preferred on
mandibular molars.
Fig.Adam's clasp with incorporated helix
4.4 Adam's clasp with additional arrowhead
An additional arrowhead is soldered onto the
bridge of the Adam's clasp. This clasp is used
when additional retention is required. The
additional arrowhead fits to the undercut of
adjacent tooth.
Fig. Adam's clasp with additional arrowhead
4.5 Adam's clasp with soldered buccal tube
Attachment of buccal tube to Adam's clasp
was described by J C Stephenson. A buccal
tube is soldered onto the bridge of the Adam's
clasp. This modification is used when an
extraoral anchorage is needed using headgear
or other assembly.
Fig. Adam's clasp with soldered buccal tube
Review Article Orthodontics
Journal of Nobel Medical College Vol. 3, No.1 Issue 5 56
4.6 Adam's clasp with distal extension
A small extension is incorporated distally in
the distal arrowhead. This distal extension
helps to engage elastics.
Fig. Adam's clasp with distal extension
4.7 Adam's clasp on incisors and premolars
This clasp is fabricated on incisors and
premolars when retention is required in those
areas. This clasp can be constructed in such a
way that it can span a single tooth or two teeth.
Fig. Adam's clasp on incisors
4.8 Smart Clasp: - A modified Adam's clasp
This clasp was developed for use with
magnetic activator device. The upper and
lower plates, with incorporated magnets, of the
appliance exert attracting or repelling force of
about 600 gm. [3] A 2 mm loop on each side of
arrowhead is given in the Adam's clasp.
5. Delta clasp
This clasp was designed by William J. Clark.
This clasp is similar to Adam's clasp in
principle. It engages interdental undercuts.
Adjustment: -hold retentive loop and twist
inwards.
-bending towards interdental undercut as it
emerges from acrylic.
Fig. Delta clasp
6. Southend clasp
This clasp was named as southend clasp
because it was developed by Mr. DiBiase and
Mr. Leavis of department of orthodontics,
Southend hospital and was used at Bristol
Hospital. It provides retention in the anterior
region. The wire is adapted along the cervical
margin of both the central incisors. The distal
end of the wire crosses over the occlusal
embrasures and end as retentive arms on the
palatal side.
Fig. Southend clasp
Review Article Orthodontics
Journal of Nobel Medical College Vol. 3, No.1 Issue 5 66
Advantages:-
Better patient compliance
Suitable for rotated and spaced incisors.
7. Triangular Clasp
It has a small triangular shape that engages the
proximal undercut of two adjacent teeth. It
provides excellent retention. It doesn't cause
irritation of gingiva. It is used when additional
retention is required.
Fig. Triangular clasp
8. Ball End Clasp
This clasp is also known as Scheau anchor
clasp. This clasp has a ball at the end which
engages the proximal undercut between two
adjacent teeth (interdental area). Preformed
wires having a ball at the end are used for
making this clasp. The ball can also be made
using silver solder. This clasp is used
whenever additional retention is required.
Fig. Ball end clasp
9. Double Ball end Clasp
This clasp includes a stem embedded into and
extending from the acrylic portion of the
appliance. Two ball clasps extend from the
stem and are laterally spaced apart from one
another. Each ball clasp has an elongated
flexible member and an enlarged exposed end.
A bridge segment extends laterally between
the flexible members of the first and second
ball clasps.
[6]
This clasp does not exert any
wedging force in the interdental embrasure like
the single ball clasp. This clasp provides better
retention.
Fig. Double boule end clasp
Review Article Orthodontics
Journal of Nobel Medical College Vol. 3, No.1 Issue 5 76
10. Schwarz Clasp
It is said to be predecessor of Adam's clasp.
This clasp has a number of arrowheads that
engage the inter-proximal undercuts of
posterior teeth.
Fig. Schwarz clasp
This clasp is not routinely used because:-
It needs special arrowhead forming pliers.
It occupies a large amount of space in the
buccal vestibule.
The arrowheads can injure the interdental
soft tissues.
It is difficult and time consuming to
fabricate.
11. Crozat Clasp
This clasp was suggested by Crozat in 1920. It
is modification of Jackson's clasp. An
additional piece of wire is soldered to the
Jackson's clasp which engages into the mesial
and distal proximal undercuts. Thus, it
provides better retention than the Full clasp.
[9]
Fig. Crozat clasp
12. Duyzing Clasp
This clasp has two wires emerging from the
plate that cross the occlusion over the anterior
and posterior contact point of the tooth
clasped. Each wire then goes above the
greatest circumference of the tooth to the
middle of the tooth and again back below using
undercuts. This clasp is used to engage the
buccal undercuts of molars.If the situation
demands, only half of the clasp can also be
made.
[5]
Fig. Duyzing's clasp
[12]
13. Eyelet Clasp
This clasp can be constructed as a single eyelet
or continuous eyelet clasp.
[5]
An eyelet is made
using a Young loop forming plier. Eyelets are
placed in the embrasure. Three to four eyelets
can be made depending upon the retention
requirement. The size of the eyelet depends on
the width of the interdental area of both anchor
teeth.
[9]
Fig. Eyelet clasp
Review Article Orthodontics
Journal of Nobel Medical College Vol. 3, No.1 Issue 5 86
14. Plint clasp
Plint clasp is also known as 'Fly Over Clasp'.
[11] Plint clasp are useful when using a
removable appliance in combination with a
fixed appliance. These clasps are constructed
using 0.7 mm stainless steel wire. [4] This clasp
is used to engage under the tube assembly on a
molar band. [10] Adjustment: - by moving the
clasp under the molar tube.
15. Visick Clasp
This clasp was given by H C Visick. This clasp
is used on palatal side for active retention
accompanying the base plate and molar clasp
on buccal side. It is made using 0.7 mm
stainless steel wire. [3] Retention is increased
with this clasp because both the buccal and
palatal surfaces are engaged. [3]
Fig. A. Visick clasp in place along with
Jackson's clasp;
Fig. B. Close up view of Visick clasp. [12]
References:
1. Bhalaji S I; Orthodontics- The art and science,
4th edition, Arya (Medi) publishing house, New
Delhi; 2009, page 298-304.
2. Adams, C P; The design, construction and use of
removable orthodontic appliances, 6th edition,
Varghese publishing house, Bombay; 1990, page
11.
3. Lohakare S S; Orthodontic Removable
Appliances, 1st edition, Jaypee Brothers Medical
Publishers (P) Ltd, New Delhi; 2008, page 55-62.
4. Martyn T C, Andrew T DiBiase; Handbook of
Orthodontics, 1st edition, Mosby Elsevier, 2010,
page -213.
Fig. Plint clasp
Review Article Orthodontics
Journal of Nobel Medical College Vol. 3, No.1 Issue 5 96
5. Rani M S , Removable Orthodontic Appliances
design, construction, application and
management; 1st edition, 1997, All India
Publishers and Distributers, Chennai, 1997, page
40-41.
6. Donal P Inman, Clasp for Removable Dental
Appliances, pub no. – US 2008/0057457/A1; pub
date – March 6, 2008.
7. http://ebookbrowse.com/principles-of-removable-
appliances-bw-pdf-d321047256
8. http://www.e-moh.com/vb/t115325/
9. http://www.o-atlas.de/eng/kapitel1_41.php;
http://www.o-atlas.de/eng/kapitel1_44.php;
http://www.o-atlas.de/eng/kapitel1_45.php;
http://www.o-atlas.de/eng/kapitel6_191.php;
http://www.o-atlas.de/eng/kapitel1_47.php;
10. http://fx.damasgate.com/removable-appliances/
11. http://universal-dental-
techniques.com/Web_page/Fly_Over_Clasp.html
12. Shridhar Premkumar; Orthodontics: Prep
manual for undergraduates, Orthodontic
appliances, Removable appliances, page 303-304;
2008 Elsevier.
Correspondence Address: Dr Mustapha Mansuri, E-mail: mustapha.mansuri@bpkihs.edu;
mansurimustapha@gmail.com Phone: +977- 9803504255; 9841502419.
... The complicated undercut of orthodontic devices makes it more difficult for keep teeth clean and causes plaque accumulation and restorations, the risk of white-spot injuries, dental caries, and periodontal complications that therefore have been suggested to result from changes in the oral microbiome [6]. Inserting orthodontic appliances into the oral cavity significantly changes the oral hygiene and increases the number of plaque retention areas. ...
- Wurood Kh Al-Lehaibi
- Khulood A Al-Makhzomi
- Hani Sh
-
![Mohammad Khursheed Alam]()
Background: The study examined the oral microbiota, physiological and immunological changes in patients using thermoplastic retainers during three months of use. Methods: The study included several steps. Firstly, 10 swabs were collected from the buccal and palatal surfaces of the teeth of the patients, approximately 2 mL of saliva was collected from the same patients and 2 mL of saliva was collected from 10 healthy people to measure the pH and secretory IgA level. This was followed by the isolation and identfication of the bacterial isolates in the patient samples. Then, isolate susceptibility toward chlorhexidine (CHX) and their adhesion ability to thermoplastic retainer surfaces was measured. In addition to that the study estimated the numbers of Lactobacillus and Streptooccus mutans colonies during three months and finally, a comparsion of pH acidity and IgA level between the patients and healthy people was performed. The results showed the predominant bacteria during the three months were Lactobacillus spp and Streptococcus spp followed by different rates of other bacteria. Raoultella ornithinolytica showed more resistance to CHX while Lactobacillus spp. showed more sensitivity. Streptococcus mutans colony levels were higher than Lactobacillus spp colonies during the three months, also S. mutans had the highest value in adherence to retainer thermoplastic. Finally, pH acidity showed a highly significant difference (p ≤ 0.05) in the third month, like IgA levels (p ≤ 0.05). Conclusions: According to the results obtained from the current study, the researchers noted that the thermoplastic retainers helped change the oral cavity environment.
Clasp for Removable Dental Appliances, pub no. – US
- P Donal
- Inman
Donal P Inman, Clasp for Removable Dental Appliances, pub no. – US 2008/0057457/A1; pub date – March 6, 2008.
The design, construction and use of removable orthodontic appliances, 6 th edition, Varghese publishing house
- C Adams
Adams, C P; The design, construction and use of removable orthodontic appliances, 6 th edition, Varghese publishing house, Bombay; 1990, page 11.
- S Lohakare
Lohakare S S; Orthodontic Removable Appliances, 1 st edition, Jaypee Brothers Medical Publishers (P) Ltd, New Delhi; 2008, page 55-62.
- Fig
Fig. Plint clasp management; 1 st edition, 1997, All India Publishers and Distributers, Chennai, 1997, page 40-41.
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Source: https://www.researchgate.net/publication/270126023_Clasps_in_Removable_Orthodontics
