The Efficacy Of The Prefabricated T4FTM Myofunctional Appliance In Comparison To Twin Block Appliance For Class II Division 1 Malocclusion Treatment: A Randomized Clinical Trial
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Date
2010-04
Authors
Hanoun, Abdulfatah Abdulrazak
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Functional appliances are widely used to treat Class II Division 1 malocclusion. No
previous studies were published about the effects of prefabricated re-mouldable
functional appliance (T4FTM) for Class II Division 1 malocclusion on Class II
skeletal pattern subjects. The aim of this study was to compare the changes in the
skeletal and dentoalveolar structures in growing Malay patients (pre-adolescent) with
Class II Division 1 malocclusion treated by Prefabricated Re-mouldable
Myofunctional appliance T4FTM and Twin Block appliance (TB). A randomized
clinical trial was carried out with a sample of 43 subjects (22 males + 21 females)
randomly assigned to active control group (Twin Block group) and experimental
group (T4FTM appliance group). At the end of six months study period and due to the
drop out, TB group consisted of 17 subjects (8 males + 9 females), while T4FTM
group consisted of 16 subjects (9 males + 7 females). Mean age was 13 years (0.7) in
T4FTM group, and 13.2 years (0.8) in Twin Block group. Pre- and post-treatment
lateral cephalometric radiographs were taken for each subject and the overjet was
clinically measured pre- and post- the six months treatment period. Twenty one
angular and linear measurements were chosen and measured separately on the preand
post-treatment lateral cephalometric radiographs. The changes during the study
period were calculated by comparing pre- and post-treatment measurements in each
group. The two groups were then compared in terms of the changes that occurred
during the study period. Intra-class Correlation Coefficient test was used to test interand
intra-examiner agreement of cephalometric measurements. (ICC) results ranged
from 0.91 to 0.99 which were considered acceptable level of errors. Independent t
test was used to compare the changes between the two groups. The between groups
comparison in terms of the changes during treatment period showed significant
difference in overjet, anterior posterior mandibular position and skeletal and
dentoalveolar discrepancies which were changed more favourably in TB group.
Overjet reduction was found to be two times more in TB group with a mean
difference of 2.1mm (p <0.01). Sella-Nasion-B point angle was more increased in TB
group with a mean difference of 1.25 ° (p <0.05). A point–Nasion-B point angle was
decreased by 0.8° (0.9) and 1.6° (1.1) in T4FTM and TB groups respectively with a
mean difference of 0.8 ° (p <0.05). The distance between Pogonion and the vertical
reference line (Sv_Pog) was more favourably changed in TB group with a mean
difference of 1.83mm (p <0.05). The distance between the lower incisal edge and the
vertical reference line (Sv_ii) was also more favourably increased in TB group with a
mean difference of 2.55mm (p <0.01). The distance between the upper and the lower
incisal edges (is_ii) was decreased in TB group as two times as in T4FTM group with
a mean difference of 1.8mm (p <0.05). The correction of the sagittal skeletal and
dentoalveolar discrepancies was favourable for both groups. The amount of changes
differed significantly between the two groups with more favourable correction in
terms of the sagittal skeletal and dentoalveolar discrepancy was observed in TB
group. The skeletal correction was due to the mandibular changes with no significant
change in terms of sagittal position of maxilla in both groups. The dental
contribution in both groups to the final overjet correction was a result of combination
of upper incisor retroclination and lower incisor proclination. The mean lower incisor
proclination that contributed to the overjet correction was higher than the mean upper
incisor retroclination in Twin Block group; while in T4FTM group, the mean upper
incisor inclination change was similar with the mean lower incisor inclination
change. In conclusion, T4FTM appliance is an effective appliance for the management
of BSI Class II Division 1 malocclusion on Class II skeletal pattern.
Description
Keywords
Functional appliances are widely used , to treat Class II Division 1 malocclusion