g.j mack and r.t.lee royal london hospital, u.k
DESCRIPTION
A Prospective Comparison of the Effects of the Twin Block Appliance and the Dynamax Appliance on the Skeletal and Dental Tissues. G.J MACK and R.T.LEE Royal London Hospital, U.K. The Royal London Hospital. AIMS. To compare the dental and skeletal effects of the Dynamax and the Twin block - PowerPoint PPT PresentationTRANSCRIPT
A Prospective Comparison of the Effects of the Twin Block Appliance and the Dynamax Appliance on the Skeletal and Dental Tissues
G.J MACK and R.T.LEE Royal London Hospital, U.K
The Royal London Hospital
AIMS
To compare the dental and skeletal effects of the Dynamax and the Twin block
To investigate the incidence of breakages and the compliance rates
SUBJECTS and METHODS
Inclusion Criteria• Caucasians• Overjet 7mm, Class II
molars • Males 12-14 years • Females 10-13 years• No relevant Medical History• No extractions
The Dynamax Appliance
Bass and Bass, JCO, 2003
The Twin Block Appliance
Gill and Lee, AJODO, 2005
Treatment Protocol
Start 3 and 6 months
9 months
12 months
Treatment Appliance Inserted
Dynamax activated
2 mm
Appliance Removed
Records Lat CephLaser Scan
HeightOJ
Laser Scan
HeightOJ
Laser Scan
HeightOJ
Lat CephLaser Scan
HeightOJ
Constructed Horizontal 7º to SN
N
ANS
Me Pog
Cephalometry
A-PointA-Point
RESULTS
Patients enrolled into Trial N=62
Males=28 Females=34
RESULTS
Patients enrolled into Trial N=62
Males=28 Females=34
Allocated to Twin block N=31
Males=14 Females=17
Allocated to Dynamax N=31
Males=14 Females=17
RESULTS
Patients enrolled into Trial N=62
Males=28 Females=34
Allocated to Twin block N=31
Males=14 =1 Females=17
Allocated to Dynamax N=31
Males=14 Females=17
Completed trial N=28
Males=13 Females=15
Completed trial N=28
Males=13 Females=15
RESULTS
Statural Height Dental Changes Skeletal Changes Compliance Breakages
Statural Height Changes 0-12 months
(P=0.88)
Dynamax Twin block
m= 57 mm
m= 67 mm
mill
imete
rs
0
50
100
150
RESULTS
Statural Height Dental Changes Skeletal Changes Compliance Breakages
Overjet Reduction 0-9 months
(P=0.20)
0
4
8
12
Dynamax Twin block
m= 5mm m= 6mm
mill
imete
rs
U1-Maxillary Plane(P=0.96)
m= -3.0ºm= -1.7º
Dynamax Twin block-12
-6
0
6
deg
rees
L1-Mandibular Plane(P=0.41)
m= 2.3º
m= 2.3º
Dynamax Twin block-5
0
5
10
deg
rees
RESULTS
Statural Height Dental Changes Skeletal Changes Compliance Breakages
A-Point to S-Vertical(P=0.77)
m= 0.4mmm= 0.1mm
-2
0
2
4
Dynamax Twin block
mill
imete
rs
Pogonion to S-Vertical(P=0.19)
m= 2.0mm m= 2.1mm
Dynamax Twin block-5
0
5
1
mill
imete
rs
Total Anterior Face Height (P=0.03)
m= 2.8mmm= 3.2mm
Dynamax Twin block
-2
0
2
4
6
8
mill
imete
rs
RESULTS
Statural Height Dental Changes Skeletal Changes Compliance Breakages
Compliance
Dynamax Twin Block
Not Completing Trial 3 3
Not Reducing Overjet by 10% after 6 months
1 1
Non Compliance Rate (%) 12 12
RESULTS
Statural Height Dental Changes Skeletal Changes Compliance Breakages
Appliance Breakages
Dynamax Twin Block
Upper Appliance
19 5
Lower Appliance
3 7
CONCLUSIONS
The dental changes were similar for both appliances
The antero-posterior skeletal changes, including mandibular advancement, were similar for both appliances
The vertical dimension increased to a lesser extent with the Dynamax
Both appliances were well tolerated More breakages occurred with the Dynamax