Page 70 - REMOVABLE ORTHODONTIC APPLIANCES

62 Removable Orthodontic Appliances
Figure 7.19 Buccal acrylic lower
appliance to retract 3|3. Lingually
placed Jackson clasps 6|6 (0.7 mm).
Buccal stainless steel connector bar
(2.0 mm X 1.0 mm half round)
springs to retract the canines.

A buccal acrylic appliance to retract lower Anchorage
canines (Figure 7.19) This is provided by the first molars only with
minimal anchorage effect from the acrylic. The
Active component original design described by Bell (1983) utilizes
Buccal canine springs 0.7 mm.
a lip bumper anteriorly to enhance the anchor-
age.
Retention
The lingually placed Jackson clasps on the
lower first molars provide retention. While
undercut is often poor on the buccal surfaces of References
these teeth, making conventional retention Barrer. H.G. (1975) Protecting the integrity of the
difficult, the lingual undercut is often good.
mandibular incisor position. Journal of Clinical Ortho-
dontics. 9: 486-494
Baseplate Bell, C. (1983) A modified lower removable appliance
This consists of two segments of acrylic resting using lingual clasping and soft tissue anchorage. British
on the buccal mucosa. These are connected in Journal of Orthodontics, 10: 162-163
the mid-line by a heavy stainless steel bar, oval
in cross-section, lying close to the buccal
mucosa below the lower incisors.