ว.ล งกวล .ออร โท.ไทย. ป ท 2 ฉบ บท 1 ม.ค.-- ม .ย. 2545 7 Treatment of Class II Division 1 Malocclusion: Asymmetric Extraction Watana Mathurasai DDS., M.D.S.,F.I.C.D,F.A.C.D. Smorntree Viteporn DDS.,M.D.Sc., F.I.C.D. The specific characteristics of Class II division 1 malocclusion that is usual ly the majorconcern of a patient is severe protrusion ofmaxillary incisors. Compromised orthodontic treatment in the adult patient is extraction only the maxillary first bicuspids so that there are enough space for correction of the protrusion and improvemen t of facial profile if possible. In a Class II division 1 patient with acceptable profile space obtained from extraction of the two maxillary first bicuspids may be redundant thus caus- ing excessive retraction of the maxillary incisors. In this case nonextraction or extraction only one bicuspid should be the treatment of choice. Factors influence success of correction of dental protrusion in the patient with accept- able facial profile are clinical examination, space assessment, anchorage management, and bio- mechanics. Since in this case the objectives ofthe treatment do not concern only function but esthetics. Excessive space obtained from extrac- tion may end up with the uprighted incisor, deep overbite, and flat facial profile due to excessive retraction of the anterior teeth. Otherwise treat- ment planning as a nonextraction case may be not possible since it aggravates the protrusion. The possibility of asymmetric extraction of only one bicuspid should be evaluated according to the aforementioned factors. Clinical examination: The initial relation between the maxillary dental midline and the facial midline should be thoroughly examined to investigate the possibility to maintain or shift the maxillary dental midline towards the extraction site. The symmetric positions of the maxillary canines when smiling has to be evaluated as well. Space assessment : The occlusogram (1) of the maxillary denture should be scrutinized to determine final position of the anterior and pos- terior segments and to select type of anchorage. Original Article Abstract Compromised treatment of Class II division 1 malocclusion in the adlut patient usually re- quires extraction of the two maxillary first bicuspids so that Class I canine can be obtained.Asymmetric extraction of one bicuspid is a treatment of choice in the patient with acceptable profile and space deficiency is moderate . Success of the treatment depends upon clinical examination, space assess- ment, anchorage management and biomechanics. The article presented treatment of Class II divi- sion 1 malocclusion with lingual orthodontic mechanics by extraction one bicuspid .
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
8/7/2019 artikel orto
http://slidepdf.com/reader/full/artikel-orto 1/6
8/7/2019 artikel orto
http://slidepdf.com/reader/full/artikel-orto 2/6
J. Lingual Ortho.Th. Vol.2 No.1 Jan.-Jun 20028
Anchorage management : Space obtained
from extraction one bicuspid is utilized for cor-
rection of protrusion by maximum retraction of the
anterior segment (Type A anchorage), retractionof the anterior segment and protraction of the
posterior segment (Type B anchorage) or pro-
traction of the posterior segment (Type C anchor-
age)(2). In lingual orthodontics, management of
anchorage is depended upon configuration of the
archwire and the amount of force.
Biomechanics : Asymmetric retraction of
the anterior segment should be a treatment of
choice if the dental protrusion cannot be
corrected by alteration of jaw relationship.
The objective of the article was to present
the Class II division 1 case treated with
asymmetric extraction by lingual orthodontic
mechanics.
Diagnosis and EtiologyA woman aged 19 years searched for cor-
rection of maxillary incisor protrusion without
changing her facial profile. Clinical examination
(figure 1) showed acceptable facial profile, nor-
mal lip position and function. The maxillary dental
midline in relation to the facial midline was shifted
to the right side 1 mm, the mandibular dental mid-
line was normal. The maxillary left posterior seg-
ment moved forward due to disto-lingual rotation
of the maxillary left canine causing severe
Figure 1 Pretreatment facial profile and occlusion
8/7/2019 artikel orto
http://slidepdf.com/reader/full/artikel-orto 3/6
. . . . 2 1 . .-- . . 2545 9
Figure 2 Pretreatment cephalometric analysis
Figure 3 Oral features during treatment
8/7/2019 artikel orto
http://slidepdf.com/reader/full/artikel-orto 4/6
J. Lingual Ortho.Th. Vol.2 No.1 Jan.-Jun 200210
Class II molar and canine relationship around 4
mm. The maxillary right segment was slightly
Class II molar and canine relation 2 mm. The
overbite was normal while the overjet was 6 mm.The Bolton analysis showed maxillary
anterior teeth excess 2 mm.
Panoramic radiograph showed normal
development dentition.
Cephalometric analysis showed skeletal
Class I normal bite with maxillary incisor
protrusion and proclination, normal facial profile
(figure 2).
Hereditary factor should be a major
etiological factor.
Treatment Objectives
To correct maxillary incisor protrusion
while maintaining the facial profile.
To obtain Class I molar (right side), Class
II molar (left side) and Class I canine (both sides)
with normal overbite and overjet.
Extraction of the maxillary left first bicus-
pid was recommended to obtain space available
8 mm for correction of the maxillary left canine
rotation and incisor protrusion. Type B anchor-
age was selected to achieve the aforemen-
tioned occlusion.
Treatment Progress (figure 3)Edgewise lingual appliance was used for