| Author, year |
Country |
Study design |
Number
of
patients (n) |
With
drawals
-
dropouts |
Results |
Comments |
Intervention
Fixed retainer |
Control
Removable retainer |
|
| Edman Tynelius [13] |
Sweden |
RCT |
n=75
Group 1
n=25
Group 2
n=25
Group 3
n=25
|
n=6
|
Maxilla
Group 1 at 2 years:
Δ LIl 0.5 (sd 0.8)
Mandible
Group 1 at 2 years:
Δ LIl 0.6 (sd 0.7)
Overjet
Group 1 at 2 years:
Δ -0.3 mm (sd 1.1)
Overbite
Group 1 at 2 years:
Δ -0.4mm (sd 1.1)
Intercanine width maxilla
Group 1 at 2 years:
Δ -1.0 mm (sd 0.8)
Intercanine width mandible
Group 1 at 2 years:
Δ 0.2 mm (sd 0.5) |
Maxilla
Group 2 at 2 years:
Δ LIl 0.9 (sd 1.1)
Group 3 at 2 years:
Δ LIl 1.1 (sd 1.4)
ns.
Mandible
Group 2 at 2 years:
Δ LIl 0.9 (sd 0.8)
Mandible
Group 3 at 2 years:
Δ LIl 1.6 (sd 1.4)
p<0.001
between group 1 and 3
Overjet
Group 2 at 2 years:
Δ 0.5 mm (sd 1.1)
Group 3 at 2 years:
Δ 0.4 mm (sd 1.0)
p< 0.05
between group 1 and 2
Overbite
Group 2 at 2 years:
Δ 0.4mm (sd 0.9)
Group 3 at 2 years:
Δ 0.2mm (sd 1.3)
ns.
Intercanine width maxilla
Group 2 at 2 years:
Δ -0.9 mm (sd 0.9)
Intercanine width maxilla
Group 3 at 2 years:
Δ -1.8 mm (sd 1.5)
p<0.01
group 1 & 2 vs. group 3
Intercanine width mandible
Group 2 at 2 years:
Δ -1.0 mm (sd 1.0)
Intercanine width mandible
Group 3 at 2 years
Δ -1.1 mm (sd 1.2)
p<0.001
group 1 vs. group2 & 3 |
Little’s Irregularity Index (LII)= the linear distance from anatomic contact point to adjacent anatomic contact point of mandibular anterior teeth (sum of five measurements)
Group 1= upper removable retainer (vacuum formed) and lower fixed retainer.
Group 2= upper removable retainer (vacuum formed) and lower stripping.
Group 3= removable retainer upper and lower (positioner).
Occlusal traits
Occlusal traits
Occlusal traits
Occlusal traits
Intermolar widths and arch lengths were statistically non-significant. between groups |
Artun
[11] |
USA |
RCT |
n=49
Group 1
n=11
Group 2
n=13
Group 3
n=11
Group 4
n=14 |
?a |
Group 1
Baseline: 0.65 (se 0.24)
At 3 years: 1.19 (se 0.27)
Group 2
Baseline: 0.20 (se 0.08)
At 3 years: 0.36 (se 0.12)
Group 3
Baseline: 0.30 (se 0.16)
At 3 years: 0.30 (se 0.16)
|
Group 4
Baseline: 0.36 (se 0.13)
At 3 years: 0.66 (se 0.25)
ns. |
Little’s Irregularity Index
Group 1= Mandibular cuspid retainer .032 plain wire
Group 2= Mandibular cuspid retainer.032 spiral wire
Group 3= Mandibular 3-3 retainer .0205 flexible spiral wire
Group 4= Removable lower retainer
Cuspid retainer- bonded only to cuspids
3-3 retainer- bonded to each tooth
Little’s Irregularity Index= the linear distance from anatomic contact point to adjacent anatomic contact point of mandibular anterior teeth (sum of five measurements) |
Cerny
[12] |
UK |
CT |
n=61
Group 1
n=46
Group 2
n=43 |
?a |
At 15 years follow up:
No relapse: 89.0%
Mild relapse: 11%
Moderate relapse: 0.0%
Severe relapse: 0.0%
Totals: 26 mm
Mean: 0.26mm |
At 15 years follow up:
No relapse: 7.0%
p<0.001
Mild relapse: 40%
p<0.001
Moderate relapse: 42%
p<0.001
Severe relapse: 11%
ns.
Mean: 3.37 mm |
Little’s Irregularity Index
Group 1= Permanent bonded retainer (PBR) (upper or lower).
Group 2= Removable retainer (RR).
Proportion individuals with relapse in the anterior teeth according to Little’s Irregularity Index relapse category:
No relapse: 0-1 mm
Mild relapse: 1-3 mm
Moderate relapse: 3-6 mm
Severe relapse: (>6 mm)
The retainers were used different times for different individuals, after treatment.
The groups were analyzed according to retainer type used for each dental arch. Not for each individual.
Smokers and those >50 years were excluded from analysis. |
