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Which orthodontic archwire sequence? A randomized clinical trial

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Which orthodontic archwire sequence? A randomized clinical trial

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The aim of this study was to compare three orthodontic archwire sequences. One hundred and fifty-four 10- to 17-year-old patients were treated in three centres and randomly allocated to one of three groups: A = 0.016-inch nickel titanium (NiTi), 0.018 × 0.025-inch NiTi, and 0.019 × 0.025-inch stainless steel (SS); B = 0.016-inch NiTi, 0.016-inch SS, 0.020-inch SS, and 0.019 × 0.025-inch SS; and C = 0.016 × 0.022-inch copper (Cu) NiTi, 0.019 × 0.025-inch CuNiTi, and 0.019 × 0.025-inch SS. At each archwire change and for each arch, the patients completed discomfort scores on a seven-point Likert scale at 4 hours, 24 hours, 3 days, and 1 week. Time in days and the number of visits taken to reach a 0.019 × 0.025-inch SS working archwires were calculated. A periapical radiograph of the upper left central incisor was taken at the start of the treatment and after placement of the 0.019 × 0.025-inch SS wire so root resorption could be assessed. There were no statistically significant differences between archwire sequences A, B, or C for patient discomfort (P > 0.05) or root resorption (P = 0.58). The number of visits required to reach the working archwire was greater for sequence B than for A (P = 0.012) but this could not be explained by the increased number of archwires used in sequence B.
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European Journal of Orthodontics 28 (2006) 561–566
doi:10.1093/ejo/cjl030
Advance Access publication 13 October 2006
Which orthodontic archwire sequence? A randomized
clinical trial
N. A. Mandall *, C. Lowe **, H. V. Worthington *, J. Sandler ***, S. Derwent *,
M. Abdi-Oskouei * and S. Ward *
* School of Dentistry, University of Manchester, ** Hightown Orthodontic Practice, Crewe, and *** Chesterfi eld
Hospital, Sheffi eld, UK
SUMMARY The aim of this study was to compare three orthodontic archwire sequences. One hundred and
fty-four 10- to 17-year-old patients were treated in three centres and randomly allocated to one of three
groups: A = 0.016-inch nickel titanium (NiTi), 0.018 × 0.025-inch NiTi, and 0.019 × 0.025-inch stainless steel
(SS); B = 0.016-inch NiTi, 0.016-inch SS, 0.020-inch SS, and 0.019 × 0.025-inch SS; and C = 0.016 × 0.022-
inch copper (Cu) NiTi, 0.019 × 0.025-inch CuNiTi, and 0.019 × 0.025-inch SS. At each archwire change
and for each arch, the patients completed discomfort scores on a seven-point Likert scale at 4 hours, 24
hours, 3 days, and 1 week. Time in days and the number of visits taken to reach a 0.019 × 0.025-inch SS
working archwires were calculated. A periapical radiograph of the upper left central incisor was taken at
the start of the treatment and after placement of the 0.019 × 0.025-inch SS wire so root resorption could
be assessed.
There were no statistically signifi cant differences between archwire sequences A, B, or C for patient
discomfort ( P > 0.05) or root resorption ( P = 0.58). The number of visits required to reach the working
archwire was greater for sequence B than for A ( P = 0.012) but this could not be explained by the increased
number of archwires used in sequence B.
Introduction
The aim of this study was to evaluate three orthodontic
archwire sequences in terms of patient discomfort, root
resorption, and time to working archwire. This is important
because the aim is to reach the working archwire not only
ef ciently but also in physiologically sound archwire steps
( Burstone and Koenig, 1974 ; Waters et al ., 1975 ; Burstone,
1981 ; Rock and Wilson, 1988 ; Tidy, 1989 ; Waters, 1992 ).
However, a balance should be made between the potential
bene ts of a more rapid progression to working wires and
risks such as root resorption ( Remmington et al ., 1989 ;
Linge and Linge, 1991 ) and patient discomfort ( Ngan et al .,
1989 ; Wilson et al ., 1989 ).
There is a lack of in vivo data to support the choice of
archwire sequence because of the dif culty in evaluating
intra-oral force levels. Rock and Wilson (1988) suggested
using clinical success factors as outcomes, including rate of
tooth movement, absence of iatrogenic damage, and patient
acceptance. The rate of tooth movement or time in initial
aligning archwires has been evaluated ( O’Brien et al ., 1990 ;
Jones and Chan, 1992 ; West et al ., 1995 ). However, archwire
sequence past initial aligning wires has not been investigated
and thus provided the focus for this trial. The null hypothesis
tested was as follows:
There is no difference in (1) patient discomfort (2) root
resorption, and (3) time to working archwire between three
archwire sequences: A = 0.016-inch nickel titanium (NiTi),
0.018 × 0.025-inch NiTi, and 0.019 × 0.025-inch stainless
steel (SS); B = 0.016-inch NiTi, 0.016-inch SS, 0.020-inch
SS, and 0.019 × 0.025-inch SS; and C = 0.016 × 0.022-
inch copper (Cu) NiTi, 0.019 × 0.025-inch CuNiTi, and
0.019 × 0.025-inch SS.
Methods
Sample size calculation
Reuker (1979) reported a mean treatment time for the
straightwire appliance system of 1.8 years with a standard
deviation (SD) of 4 months. It was hypothesized in the
present investigation that if the time to reach the working
archwire were 3 months shorter for one archwire sequence,
with a SD of 4 months, this would be clinically signi cant
in terms of ef ciency. When the sample size in each of
the three groups was 40, a one-way analysis of variance
(ANOVA) would have a 99 per cent power to detect, at the
0.05 level, a difference in means characterized by a variance
of means of 3 months assuming the common SD is 4 months.
This gave a total sample size for the trial of 120. One
hundred and fty-four patients were registered to allow for
a drop-out rate of just over 20 per cent.
Ethical approval was obtained from the Central
Manchester Local Research Committee (No. CEN/00/185)
and written parent and child consent taken for patients at the
University Dental Hospital of Manchester, Hope Hospital
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N. A. MANDALL ET AL.
(Salford), and a specialist orthodontic practice (Crewe,
UK). Patients with pain from any other medical or dental
condition that may have affected their reported discomfort
scores were excluded. The inclusion criteria were <18 years,
upper and lower pre-adjusted edgewise appliance (0.22-
inch slot), and non-extraction or up to four premolar
extractions.
Patients reporting a history of trauma (crown fracture or
avulsion and re-implantation), central incisor root lling, or
pre-existing root resorption (identi ed as radiographic
blunting of the root apex of the upper left central incisor)
were not excluded, but these factors were taken into account
in the statistical analysis.
Randomization was carried out by throwing an
unweighted die where 1 and 2 = archwire sequence A, 3 and
4 = sequence B, and 5 and 6 = sequence C. A restricted
randomization was used in blocks of 12 to ensure equal
allocation of patients to the treatment groups. Random
allocation was concealed in thick opaque envelopes. Only
when the patient was registered was the next consecutive
envelope opened, ensuring that the clinician and patient
were blind to the treatment allocation until the patient was
registered in the trial.
Intervention and outcome measures
The planned intervention was one of three archwire
sequences used to reach the working archwire (0.019 ×
0.025-inch SS). All archwires were manufactured by Ormco
(Amersfoort, The Netherlands), including 35 degrees
thermoactive CuNiTi.
All archwires were left in place until they were passively
engaged in all bracket slots before proceeding to the next
archwire in the sequence. Since this was a realistic study,
it was left to clinical judgement whether to use elastic or
wire ligatures and canine lacebacks. As a result of the
randomization process, variables such as method and extent
of ligation, lacebacks, push coil, and duration of time
between appointments were divided with equal probability
between groups A, B, and C.
Full or partial engagement of the initial aligning wires
was not thought to in uence discomfort levels because of
the nature of the hysteresis curve exhibited by the NiTi
archwires, whereby an increased wire de ection does not
result in a proportional increase in force levels. However,
the clinicians were asked not to place a palatal arch,
quadhelix, or headgear at the same visit as the initial
archwire so that discomfort from the former appliances did
not in uence archwire discomfort scores.
Three outcome measures were assessed: (1) patient
discomfort at each archwire change and total discomfort for
each archwire sequence, (2) root resorption (root length) of
an upper left central incisor (in mm), and (3) time to reach
upper and lower working archwire (0.019 × 0.025-inch SS)
in months, and also the number of visits.
The following baseline data were collected: age and
gender, operator level (staff or postgraduate student),
type of malocclusion, extraction or non-extraction
treatment, upper and lower labial segment crowding,
irregularity index ( Little, 1975 ) for upper and lower labial
segments, and start of treatment periapical of the upper
left central incisor.
When the archwires were changed, the patients recorded
their discomfort on a seven-point Likert scale at 4 hours, 24
hours, 3 days, and 1 week for the upper and lower arches
separately ( Ngan et al ., 1989 ; Wilson et al ., 1989 ). The
patients were given discomfort data sheets, as required, at
the end of their adjustment appointment and asked to return
them at the following visit.
The upper left central incisor was used as an indicator of
likely root resorption and root length measurements were
recorded by two authors (SD and MA-O) who were
previously calibrated to use dial callipers (Mitutoyo,
Andover, Hampshire, UK) accurate to a 10th of a millimetre.
An upper incisor was chosen because it has been suggested
that these are at most risk of root resorption ( Remmington
et al ., 1989 ). The length of the crown from the cemento-
enamel junction to the incisal tip was measured from a
periapical radiograph taken at the start of treatment (C1)
and after the working archwire was placed (C2). A
correction factor for enlargement between the start and
end-point radiograph was calculated as C1/C2. Apical root
resorption was measured as root length at the start of
treatment (R1) minus root length at the end of alignment
(R2) and multiplied by the correction factor ( Linge and
Linge, 1991 ):
Apical root resorption = R1 R2 ×( C1/C2 ).
Labial segment crowding was assessed by one author
(NAM) by calculating the difference between the sum of
the mesio-distal widths of the incisors and canines and the
arch space available between the distal contact points of
the canines. The latter was measured by summing the
distance between the distal contact point of the canine and
the mesial contact point of the central incisor on both sides
of the arch. Labial segment irregularity was recorded
according to the irregularity index ( Little, 1975 ). Intra-
examiner reliability was assessed by remeasuring 20 cases
at least 1 week later.
At the end-point of the trial, when 0.019 × 0.025-inch SS
wire had been passively placed in both arches for at least 4
weeks, a second periapical radiograph of the upper left
central incisor was taken. The time taken and the number of
visits to reach the working archwire were recorded from the
patient notes.
At the end of the trial, the case notes were checked for
any other protocol violations i.e. designated archwire
sequence not being used, and the reasons for this were
recorded. Such patients were still included in the intention
to treat analysis. For some patients, 0.016 × 0.022-inch
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CLINICAL CHOICE OF ORTHODONTIC ARCHWIRES
CuNiTi was ineffective for severely rotated premolars.
Therefore, if 0.016 × 0.022-inch CuNiTi was ineffective
and had been in place >6 months, it was agreed to keep the
patient in the study but change the initial aligning wire to
0.016-inch NiTi.
Method error
Systematic error was reduced by ensuring that the examiner
was blind to the archwire allocation when labial segment
crowding, Little’s index, and root resorption were measured.
In addition, root resorption measurements were made
in a random order so that patients’ start and end-point
radiographs were not measured consecutively. It was not
possible to blind either the treating clinicians or the
examiner (SW) who recorded time to working archwire
from the patient notes.
Random error was reduced by taking measurements
twice and calculating a mean score for root lengths, labial
segment crowding, and Little’s index.
Statistics
Summary statistics were calculated and the data checked
for normality. ANOVA was used to compare archwire
sequence groups for the main outcome measures. Intra-
examiner reliability for the dial calliper measurement was
assessed using intra-class correlation coef cients (ICCs).
Systematic error was quanti ed by examination of the
difference and 95 per cent con dence intervals.
Results
Table 1 shows the number of patients in each group and the
reasons for any dropouts. There was no apparent systematic
error for any of the outcomes, as the differences between
means were very small and the 95 per cent con dence limits
narrow. ICC revealed high intra-examiner reliability for
Little’s index (0.99), labial segment crowding (0.96), and
root length (0.98).
The characteristics of the patients in each archwire
sequence group are summarized in Tables 2 and 3 . Up to
one-third of patients had reported upper incisor trauma.
There were more females than males, which re ects the
uptake of orthodontic treatment, with the exception of
group A where 60.8 per cent of patients were male. The
distribution of the type of malocclusion and extraction/
non-extraction cases was similar between the archwire
sequence groups. ANOVA revealed no statistically
signi cant differences between archwire sequences
for labial segment crowding ( P = 0.56) or Little’s index
( P = 0.46). An intention to treat statistical analysis was
carried out, whereby data for patients who did not receive
the correct allocated archwires were included in the
analysis ( n = 4).
The in uence of operator experience on
outcome variables
T -tests were used to evaluate whether operator experience
in uenced any of the outcome variables. In summary,
reported discomfort at 24 hours (maximum discomfort) was
similar for postgraduate ( n = 8) and staff ( n = 2) patients
( P > 0.05) except for lower arch/sequence C where mean
discomfort was 3.3 for staff and 5.2 for postgraduates
( P = 0.015). Root resorption was not statistically signi cantly
different for staff or postgraduates ( P = 0.41). Postgraduates
took a slightly longer time to reach the upper working
archwire only ( P = 0.022) and more visits to reach upper
and lower working archwires ( P < 0.05). Therefore, operator
experience was factored into the analysis for time and
number of months to working archwire.
Archwire sequence and patient discomfort
Mean discomfort scores at different time intervals for each
archwire sequence are shown in Table 4 . For example, the
score at 4 hours for sequence A indicates the mean discomfort
experienced for the whole archwire sequence at 4 hours
(0.016-inch NiTi, 0.018 × 0.025-inch NiTi, and 0.019 ×
0.025-inch SS). ANOVA did not reveal any statistically
signi cant difference in reported discomfort between
archwire sequences A, B, or C ( F ratio, P > 0.05). In
addition, there was no statistically signi cant difference
between the proportion of patients who returned/did not
return discomfort data in groups A, B, or C [chi-square
value 0.49, P = 0.79, 2 degrees of freedom (df)]. This
suggested that there was no evidence of bias towards
patients returning data as potentially they may have
experienced more discomfort.
Table 1 Trial pro le.
Archwire sequence
Sequence A Sequence B Sequence C
Received standard
intervention
51 50 53
Protocol violations 0 2 * 2 *
Followed up 41 44 44
Withdrawn (total) 10 6 9
Reasons for withdrawal
Lost for follow-up
(failed appointments)
74 5
Patient requested
appliance removal
20 2
Obtained treatment
elsewhere
01 0
Operator stopped treatment
Repeated breakages 1 0 1
Poor oral hygiene 0 1 1
Completed trial 41 44 44
* Patients with protocol violations in sequence B and C were still included
in the analysis as an intention to treat statistical analysis was used.
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N. A. MANDALL ET AL.
Archwire sequence and root resorption
Mean root resorption for archwire sequence A was 0.96 mm
(SD 1.0 mm), sequence B 1.39 mm (SD 1.8 mm), and
sequence C 1.19 mm (SD 1.5 mm). ANOVA revealed no
statistically signi cant difference between archwire
sequences, for upper left central incisor root resorption ( F
ratio, P = 0.58). However, this should be interpreted with
caution as the SDs were large. There was also no statistically
signi cant difference between the proportion of patients
with/without root resorption data between archwire
sequences (chi-square value 5.0, P = 0.80, 2 df). Additionally,
reported history of incisor trauma was not associated with
increased root resorption ( t -test: P = 0.59).
Archwire sequence and time to 0.019 × 0.025-inch
SS working archwire
The mean time taken and the number of visits to reach 0.019
× 0.025-inch SS working archwire are shown in Tables 5
and 6 . Operator experience was factored into the ANOVA
for this variable. Although there was a trend for sequence B
to take longer, there was no statistically signi cant difference
between archwire sequences for time taken ( F ratio, P >
0.05). However, sequence B required statistically
signi cantly more visits, before the working archwire was
placed, compared with sequence A ( F ratio, P = 0.007 for
upper arch and P < 0.001 for lower arch).
There was no statistically signi cant difference between
the proportion of patients with complete/incomplete data
for this variable (chi-square value 0.70, P = 0.71, 2 df).
Discussion
This trial showed that no archwire sequence tested was more
effective than another, in terms of reported patient discomfort
or upper incisor root resorption. However, clinicians may
choose a NiTi sequence with the aim of reducing the number
of visits to reach the working archwire. There are other
factors that in uence the choice of archwire progression,
such as personal preference and cost, and these should be
considered equally alongside the clinical evidence
presented.
Importantly, the archwire sequences investigated do not
appear to cause unacceptable iatrogenic root resorption or
high levels of patient discomfort.
It is dif cult to compare this data with the previous
literature as other archwire trials evaluated initial aligning
wires only ( O’Brien et al ., 1990 ; Jones and Chan, 1992 ;
West et al ., 1995 ). However, it would seem that an ef cient
archwire sequence of 0.016-inch NiTi, 0.018 × 0.025-inch
NiTi, and 0.019 × 0.025-inch SS suggested by Tidy (1989)
is now clinically supported.
When separate outcomes are considered, root resorption
in this study was similar to that reported by Linge and Linge
(1991) of 1.54 mm. Additionally, when clinically signi cant
root loss is considered as >2.5 mm, the results are also
comparable with Linge and Linge (1991) reporting 16.5 per
cent of patients affected and this trial 18.1 per cent. It may
be that the present results underestimate root resorption as
the data only record up to the passive placement of working
archwires and not to the end of treatment. In addition,
although baseline risk variables such as the presence of a
root lling were recorded, these were small in number and
statistical analysis was not carried out.
A previous trial by Jones and Chan (1992) showed no
statistically signi cant differences in discomfort between
0.015-inch twist ex and 0.014-inch Japanese NiTi. Although
different archwires and sequences of archwire were
compared, the results of this trial support their data in that
patient discomfort was not in uenced by the type of archwire.
Table 2 Descriptive statistics for each archwire sequence for the
patients enrolled in the trial.
Archwire sequence
A B C
Mean age in years (SD) 13.8 (1.6) 14.4 (1.9) 14.4 (1.8)
Gender (%)
Male 31 (60.8) 13 (26.0) 18 (34.0)
Female 20 (39.2) 37 (74.0) 35 (66.0)
History of incisor trauma (%)
Yes 14 (27.5) 6 (12.0) 11 (20.8)
No 37 (72.5) 44 (88.0) 42 (79.2)
Root lled upper left central incisor (%)
Yes 1 (2.0) 0 (0) 0 (0)
No 50 (98.0) 50 (100) 53 (100)
Pre-existing root resorption upper left central incisor (%)
Yes 1 (2.0) 0 (0) 0 (0)
No 50 (98) 50 (100) 53 (100)
Table 3 Occlusal descriptives according to archwire sequence
for patients enrolled in the trial.
Archwire sequence
A B C
Type of malocclusion (%)
Class I 13 (25.5) 13 (26.0) 19 (35.8)
Class II division 1 18 (35.3) 18 (36.0) 17 (32.1)
Class II division 2 12 (23.5) 9 (18.0) 6 (11.3)
Class III 8 (15.7) 10 (20.0) 11 (20.8)
Extraction/non-extraction (%)
Extraction 32 (68.1) 35 (70.0) 37 (71.2)
Non-extraction 15 (31.9) 15 (30.0) 15 (28.8)
Mean labial segment crowding [mm (SD)]
Upper 4.01 (4.3) 3.77 (4.71) 3.20 (4.26)
Lower 3.26 (2.63) 3.10 (2.36) 3.55 (2.66)
Little’s index [mm (SD)]
Upper 10.70 (6.10) 10.48 (6.54) 9.60 (6.40)
Lower 6.49 (5.05) 5.72 (4.31) 6.05 (4.75)
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CLINICAL CHOICE OF ORTHODONTIC ARCHWIRES
Table 4 Mean discomfort scores over time for each archwire sequence * .
Sequence Mean discomfort
at 4 hours (SD)
Mean discomfort at
24 hours (SD)
Mean discomfort
at 3 days (SD)
Mean discomfort
at 1 week (SD)
Lower Upper Lower Upper Lower Upper Lower Upper
A 2.9 (1.8) 3.5 (2.1) 2.9 (1.6) 3.3 (1.7) 1.9 (1.1) 2.2 (1.8) 1.2 (0.4) 1.3 (0.9)
B 3.8 (1.7) 3.9 (2.0) 4.2 (1.8) 4.0 (1.8) 2.3 (1.2) 2.3 (1.0) 1.5 (0.9) 1.4 (0.6)
C 3.6 (1.6) 3.3 (1.7) 4.0 (1.6) 3.6 (1.5) 2.7 (1.1) 2.5 (1.3) 1.5 (0.4) 1.7 (0.8)
Likert scale 1 7: 1 = no discomfort at all, 7 = signi cant discomfort.
* No statistically signi cant difference between archwire sequences (ANOVA; F ratio, P > 0.05).
Table 5 Mean time taken to placement of 0.019 × 0.025-inch SS
working archwire according to archwire sequence.
Archwire
sequence
Mean time taken to
placement of working
archwire in months (SD)
Mean number of visits
to placement of working
archwire (SD)
A
Lower 6.8 (2.5) 5.7 (2.1)
Upper 6.7 (3.5) 5.4 (2.1)
B
Lower 9.3 (4.4) 7.5 (1.9)
Upper 7.9 (3.5) 7.1 (2.6)
C
Lower 8.3 (4.2) 6.4 (2.2)
Upper 7.1 (3.4) 5.9 (2.8)
Missing data
There was some missing data in this trial mostly because of
patients not returning their discomfort scores, inadequate or
illegible information in the notes, and radiographs not showing
the root apex of the upper incisor. Table 7 shows the number
of patients with complete data for each outcome. However,
analysis suggested that there was no statistically signi cant
difference, and therefore no bias, between the proportion of
patients for whom data were or were not available.
It is possible that patients not returning discomfort sheets
experienced less pain than those who returned data. However,
as the reported discomfort was low, non-returners experiencing
less discomfort are likely to be clinically insigni cant.
Conclusions
The archwire sequences investigated were not statistically
signi cantly different in terms of patient discomfort and
Table 6 ANOVA (Bonferroni correction) comparing the
number of visits to placement of working archwire.
Dependent
variable
Archwire
sequence
Mean
difference
Standard
error
P value
95% con dence
interval
Number
of visits
to upper
working
wire
A
B
B
C
C
1.6
0.5
1.1
0.5
0.5
0.5
0.007
1.00
0.10
2.9 to 0.4
1.8 to 0.8
0.15 to 2.4
Number
of visits
to lower
working
wire
A
B
B
C
C
1.8
0.7
1.1
0.4
0.5
0.4
<0.001
0.34
0.06
3.0 to 0.7
1.8 to 0.4
0.02 to 2.1
As this study did not nd any clinical factors that may
in uence the choice of archwire, consideration may be
given to cost. It is also clinically important to note that two
patients receiving sequence C had severe premolar rotations
where 0.016 × 0.022-inch CuNiTi was ineffective. This
was because it could not be tied in adequately due to a
very short interbracket span. It may therefore be more
advantageous to use another aligning archwire in these
instances.
Table 7 Number of patients with complete data for main
outcomes.
Outcome Archwire
sequence
Number or
range of
subjects with
complete data
Number of
subjects
registered
in trial
Number of
subjects
completing
trial
Pain A Range 15 – 22 51 41
B Range 11 – 16 50 44
C Range 15 – 16 53 44
Root
resorption
A
B
C
28
29
37
Time/months to working archwire
Upper A 41
B41
C39
Lower A 35
B40
C 3 4
Numbers in archwire groups are based on an ‘ intention to treat analysis ’
where patients not receiving the allocated treatment are still included in
the statistical analysis. The number of patients remaining in the trial, in
each group, is included in the table for reference.
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N. A. MANDALL ET AL.
upper incisor root resorption. However, clinicians may
choose sequence A to minimize the number of visits to the
working archwire.
Address for correspondence
Dr N. A. Mandall
School of Dentistry
University of Manchester
Higher Cambridge Street
Manchester M15 6FH
UK
E-mail: nicola.a.mandall@manchester.ac.uk
Acknowledgements
This study was supported by the British Orthodontic Society
Research/Audit Fund. Many thanks go to the following
specialised registrars who registered and treated a number
of patients for this trial and who also collected patient
discomfort data and periapical radiographs: L. Harvey, B.
Doherty, N. Manning, B. Kiptanui, K. Ioannou, M. Heanue,
J. Miller, A.-M. Isaac, S. Vine, and S. Deacon, School of
Dentistry, University of Manchester, UK.
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... Treatment duration is highly variable from one country to another and, to some extent, dependent on the type of service in which it is delivered as well as the local health care and remuneration system. Treatment duration is also influenced by the severity of malocclusion, the training level, experience and ambition of the clinician, and the types of monitoring techniques employed during treatment (Mandall et al., 2006). An average fixed orthodontic appliance treatment is about 18 months (1.5 years) including an approximate Στην παρούσα μελέτη, χρησιμοποιήθηκαν μίνι εμφυτεύματα για τη μετατόπιση των κυνοδόντων λόγω της απλής τεχνικής τοποθέτησης και λόγω του ότι με αυτό τον τρόπο ήταν δυνατό να εξαλειφθεί η εξάρτηση από τη συμμόρφωση του ασθενούς. ...
... Οι περισσότερες μελέτες με ζώα, αξιολόγησαν, επίσης, και δείγματα αίματος και GCF, καθώς και ιστολογικές CalCitriol and orthodontiC tooth MoveMent helleniC orthodontiC review 6-month duration for the 2nd phase (canine retraction or space closure phase). Mandall et al. suggested that twelve weeks reduction in treatment time, in comparison to the commonly known treatment time, is clinically significant in terms of efficiency (Mandall et al., 2006). A limitation of the current study is that the size of the sample is limited. ...
... Group C -0.016 × 0.022 CuNiTi wire, followed by 0.019 × 0.025 CuNiTi, and ending with 0.019 × 0.025 Steel wire, And found that all sequences were equally effective. However, the CuNiTi may be preferred by the clinicians as it reduces the number of appointments [14]. ...
Chapter
Full-text available
In orthodontics there has been a change in the treatment plan of crowding cases from extraction protocol. This was mainly due to the introduction of self-ligating bracket and temperature activated wires. Even though there are certain exceptions, the self-ligating bracket have evolved in orthodontics because of its advantages such as low friction, shorter treatment duration and increased efficacy. Damon’s self-ligating system has been in existence since 1930 but it has been well developed in the past 30 years with the introduction of newer systems. Damon’s self-ligating brackets have been designed to overcome the drawbacks of conventional bracket system and are often considered as the pinnacle of bracket technology. The main advantage of Damon’s system was low friction and shorter treatment duration. But the efficiency of the appliance is influenced by several factors such as Biomechanics, frequency of dental visits and patient comfort. The chapter will highlight the efficiency of the appliance, the various possible outcomes and its influence on the ease of orthodontic therapy.
... These investigators were driven by the fact that rectangular wires of the specific alloys are indicated as finishing wires when effective torque control is needed. In addition, particular archwires are ideal for segment stabilization and as a substitute of nickel titanium wires in cases of nickel allergies [25][26][27]. ...
Article
Full-text available
This study aimed to investigate the force values exerted from rectangular wires when combined with conventional labial and fully customized lingual appliances under predefined, idealized activation. Fully customized lingual brackets of two brands Incognito™ (3M Unitek, Monrovia, MN, USA) and WIN (DW Lingual Systems, Bad Essen, Germany) and labial brackets of another brand, discovery® MIM and discovery® smart systems (Dentaurum, Ispringen, Germany), were chosen. Stainless-steel and beta-titanium wires of 0.018” × 0.025” were examined. For IncognitoTM, 0.0182” × 0.025” beta-titanium wires were tested. Intrusion/extrusion and orovestibular movements were performed in a range of 0.2 mm, and the forces were recorded for each 0.1 mm of the movement. Mean values and standard deviations were calculated for all measurements, and ANOVA was performed for statistical analysis. Slight differences were observed between the forces generated from beta-titanium and stainless-steel wires. The same wire generated in some cases 5–53% higher forces with the lingual appliance due to the vertical orientation of the long walls during intrusion/extrusion and increased wire stiffness at the anterior region. Beta-titanium and stainless-steel 0.018” × 0.025” wires can generate similar force values during the final stages of the orthodontic therapy; thus, possibly only one of the two alloys could be used in each orthodontic wire sequence.
... Furthermore, it would be a small part of the overall treatment time. In a previous study that used a wire sequence similar to ours, the mean time for completion of alignment and levelling in the mandibular arch was 6.8 months (11). For the same group, the standard deviation (SD) was 2.5 months. ...
Article
Introduction: This study investigated the effect of the timing of second molar bonding on the time required for the levelling of the mandibular dental arch. Trial design: Single-centre two-arm parallel randomized clinical trial using random permuted blocks. Allocation concealment was achieved through sealed envelopes. There was blinding in outcome assessment, but not of patient or operator. Methods: Thirty-six patients (12-18 years old) with mild to moderate crowding and fully erupted mandibular second molars were assigned randomly (1:1 ratio) in two groups. Group A started fixed orthodontic treatment by bracket bonding in both jaws. Initial wire was 0.014" NiTi. Lower second molar tubes were bonded at the time of 0.016" x 0.022" NiTi wire placement. Group B was same as Group A, but second lower molars were bonded at the first appointment. Placement of the 0.017" x 0.025" stainless steel wire in the mandibular arch was considered the primary endpoint of the trial, indicating the completion of the levelling phase. The days required from bonding to the endpoint comprised the main outcome. Non-parametric statistics were applied. Results: There were two dropouts in each group. The compared groups had similar baseline characteristics regarding age, sex, overjet, overbite, space in the dental arch, average Curve of Spee (CoS), and maximum CoS. Group A tended to require more days for levelling (median: 203 days) than Group B (median: 168 days). However, this difference was not statistically significant (P = 0.128). From the tested occlusal factors, only initial overjet was found to be moderately associated with the days required to complete levelling of the mandibular arch (r = 0.45, P = 0.009). Conclusions: In the frame of the current study, the duration of the levelling phase of orthodontic treatment with fixed appliances was not affected by the timing of second molar inclusion in the appliance. Future research could aim in cases with deep CoS to generalize the present findings and in larger sample sizes.
... In an attempt to achieve rapid tooth movement, many researchers have used different approaches including chemical agents, such as prostaglandin E 2 [4], calcitriol (active form of vitamin D 3 ) [5][6][7], and hormones [8]. Moreover, physical agents such as electric currents [9], electromagnetic fields [10], vibrating devices [11], and lowlevel laser therapy [12,13] or combination of two techniques have been used to accelerate tooth movement [14]. ...
Article
Full-text available
Background/Purpose. In the literature, no consensus about the duration of orthodontic treatment has been reached out. This study aimed to identify orthodontist’s and patient’s perception about the time of orthodontic treatment and their willingness to undergo and pay for various acceleration techniques and procedures. Materials and Methods. An electronic survey was conducted from August to October 2020. The questionnaire consisted of 20 multiple choice questions which was designed and emailed to members of the Iraqi Orthodontic Society and self-administered to patients in several orthodontic centers in Baghdad. The questionnaire included questions about the perception toward the duration of orthodontic treatment, approval of different procedures used to reduce treatment time, and how much fee increment they are able to pay for various techniques and appliances. Descriptive and chi-square test statistics were used, and the level of significance was set at p≤0.05. Results. The response rate was 78.7%. The willingness for additional techniques and procedures was rated in the following order: customized appliances: 50.8% orthodontists and 38.4% patients, followed by intraoral vibrating devices: 49.2% orthodontists and 38.1% patients, piezocision: 10.2% orthodontists and 8.2% patients, and corticotomies: 8.1% orthodontists and 5.9% patients. Most orthodontists were willing to pay up to 40% of treatment income for the acceleration procedure, while the payment of patients was up to 20%. Conclusion. Both orthodontists and patients were interested in techniques that can decrease the treatment duration. Noninvasive accelerating procedures were more preferable by orthodontists and patients than invasive surgical procedures.
Chapter
Full-text available
The function of respiration is highly relevant to orthodontic diagnosis and treatment planning. Significant relationships between pharyngeal, craniofacial as well as dentofacial structures have been reported in several studies. Many authors have emphasized that mouth breathing is concomitantly associated with constricted airway causing obstructive sleep apnoea. Associated symptoms can be cured with correction of either skeletal or dental problems or both. Therefore it would be very intriguing to understand and interpret the airway during diagnosis and treatment planning for a clear view of changes in the airway dimensions during the course of orthodontic treatment using various treatment modalities. Therefore a complete understanding of the concept of airway should be considered as an important one. This chapter gives us an insight to the intricate detailing on how the various orthodontic and dentofacial orthopedic treatment signifies the changes in the dimensions of pharyngeal airway.
Article
Introduction A key goal of orthodontic treatment with fixed appliances is alignment of the dentition, and this remains a commonly selected outcome in clinical studies investigating orthodontic tooth movement. This systematic review has evaluated treatment duration to achieve alignment of the mandibular dentition using fixed appliances. Methods Systematic literature searches without restrictions were undertaken in 9 databases for randomized clinical trials (RCTs) assessing duration and rate of tooth alignment using fixed appliances with or without treatment adjuncts published up to January 2021. After duplicate study selection, data extraction, and risk of bias assessment according to Cochrane, random-effects meta-analyses of aggregate data, and individual patient data were conducted. Results Thirty-five trials were included with 2258 participants (39% male; mean age 17.8 years), giving a pooled duration to achieve whole-arch alignment of the mandibular dentition of 263.0 days (4 trials; 95% confidence interval [CI], 186.7-339.4 days) and incisor alignment in the mandibular arch of 100.7 days (9 trials; 95% CI, 84.1-117.4 days). Surgical-assisted orthodontics was associated with reduced duration of incisor alignment: mean difference of 44.3 days less (4 trials; 95% CI, 20.0-68.9 days; P <0.001; high quality of evidence), whereas subgroup and meta-regression analyses indicated significant effects of baseline crowding and premolar extractions. Individual patient data analysis from 3 RCTs indicated that for each additional participant age year, whole-arch alignment of the mandibular dentition took 13.7 days longer (3 trials; 95% CI, 7.7-17.7 days; P <0.001) and for each additional mm of irregularity, 17.5 days more were needed (2 trials; 95% CI, 9.8-25.2 days; P <0.001). Conclusions Patient and treatment-related characteristics can significantly affect the duration of tooth alignment and should be taken into account both clinically and when designing trial outcomes. Future research studies investigating rates of orthodontic tooth alignment would benefit from adequate sample sizes and a more consistent methodology in outcome assessment. Data in this systematic review provides a basis for appropriate trial design for future RCTs investigating the rate of orthodontic tooth alignment with fixed appliances.
Article
External apical root resorption (EARR) is one of the most frequently reported iatrogenic side effects of orthodontic movement. Nevertheless, no robust and unequivocal scientific evidence is yet available in the literature regarding the clinical and biological factors that trigger EARR. The purpose of the present position paper is to provide clinicians, residents, and investigators a summary of our current understanding about root resorption caused by orthodontic tooth movement, based on up-to-date available scientific evidence. Morphological, structural, biomechanical, and biological differences account for predisposing the apical third to EARR compared to other root surfaces during orthodontic treatment. In addition, a relevant number of patient and treatment-related factors increase risk of EARR. The main patient-related factors are reviewed and discussed: genetic factors, tooth anatomy, demographic factors, malocclusion factors, previous endodontic treatment, medical history, short root anomaly. Similarly, the influence of treatment-related factors are analyzed with regard to the effect of: biomechanical factors, type of orthodontic appliance, adjunctive therapies to accelerate tooth movement, early treatment, maxillary expansion, teeth extractions, the duration of treatment and the amount of apical displacement. Clinical management of EARR from pre-treatment records to the monitoring strategy as well as recommendations for the post orthodontic-treatment period are presented as a guide for the clinician. Despite years of studies, we still do not fully understand EARR, but the future is promising. True three-dimensional imaging with higher resolution and low radiation, and predictive tools towards an earlier detection without radiographs, will mark future developments in the field of EARR in orthodontics.
Article
Objective To investigate the surface topography and ultimate tensile strength of 3 types of nickel–titanium (NiTi) wires before and after 3 months of intraoral use and to assess the efficiency of the wires in cases requiring extensive alignment. Methods NiTi wires of 0.016″ (0.40 mm) were divided into 3 groups—martensitic stabilized NiTi™ (group 1), austenitic active Copper NiTi™ 27°C (group 2), and martensitic active copper NiTi™ 35°C (group 3)—each further divided into 2 subgroups: (a) as-received wires; and (b) used wires. Each wire was subjected to scanning electron microscopy (SEM) analysis and tensile testing. Ultimate tensile strength data were analyzed using one-way analysis of variance (ANOVA) and Tukey testing at the .05 level of significance. Results Martensitic stabilized archwires had a significantly lower ultimate tensile strength (93.99 ± 0.23 MPa) than martensitic active (116.96 ± 0.43 MPa) and austenitic active (106.94 ± 0.36 MPa) archwires. Among the used archwires, the martensitic stabilized ones showed the most and the martensitic active ones the least surface degradation. Conclusion Ultimate tensile strength was the highest for martensitic active archwires with superior surface properties and the lowest for martensitic stabilized archwires with an increased amount of surface degradation.
Chapter
This chapter discusses the definitions of archwires physical properties and at what stages of treatment specific ones are more advantageous. The processes of intraoral ageing and fatigue and the different types of corrosion are important considerations in orthodontics, as these may change the physical properties of archwires. The elastic behaviour of any material is defined in terms of its stress–strain response to an external load, which can be plotted on a stress–strain curve. In the laboratory, wires are tested for their physical properties with either cantilever‐type tests or three‐point bending tests. Archwires can be classified by shape or material. Before the development of stainless steel, precious alloys were used for archwires, as they were one of the few materials that would withstand oral conditions. The little research available assessing the effect of aligning archwires on root resorption and pain was highlighted in the Cochrane review by Wang et al.
Article
Full-text available
The physical properties of a super-elastic archwire alloy (Titanol) and Nitinol were investigated by the means of a bending test. It was found that the alloy possessed super-elastic properties. A clinical trial was then carried out to compare the properties of two types of aligning archwire. Two groups of 20 patients with crowded dentitions were randomly allocated either Titanol or Nitinol, a conventonal nickel-titanium alloy aligning archwire. High quality alginate impressions were taken after archwire placement in Edgewise fixed appliances and were repeated after a mean period of 35 days. The impressions were cast in dental stone and digitized using the Reflex Metrograph. The contact points of the teeth of the labial segments, together with four stable points in the rugae were recorded. This enabled the co-ordinates for the sequential study models to be superimposed upon one another, allowing tooth movement in three dimensions to be calculated. The measurement error expressed as error variance was 0.028 mm. The coefficient of reliability was 97 per cent. When tooth movement was analysed the mean movement per contact point for Titanol was 1.7 mm and for Nitinol 1.42 mm. This difference was not statistically significant (P>0.05, t-test). However, a clinical impression was that the super-elastic archwire proved superior to the Nitinol, because it was more readily engaged into grossly displaced teeth.
Article
The characteristics of single spans of plain and looped archwires are examined. Plain archwires have similar flexibility in both vertical and horizontal deflections but even with thin wires, the loads applied by small deflections are very high. The incorporation of vertical loops reduces span stiffness particularly for horizontal deflections. However, if maximum flexibility is to be obtained, careful attention must be paid to the dimensions of the loops. The stiffness of the looped arch is very much greater in the vertical plane than in the horizontal plane. Bracket width has a greater influence on span stiffness than has generally been ackowledged. The wider the bracket, the stiffer a span will be. This effect is particularly important with plain arches and with looped arches in vertical deflection. The forces exerted even by small deflections of inital aligning arches are high and exceed by a considerable margin the values normally considered as light.
Article
A quantitative method of assessing mandibular anterior irregularity is proposed. The technique involves measurement directly from the mandibular cast with a caliper (calibrated to at least tenths of a millimeter) held parallel to the occlusal plane. The linear displacement of the adjacent anatomic contact points of the mandibular incisors is determined, the sum of the five measurements representing the Irregularity Index value of the case. Reliability and validity of the method were tested, with favorable results. At the University of Washington, several clinical studies have been and are continuing to be performed, using this technique as one of several methods of assessing pretreatment status and posttreatment change. It is hoped that this article will aid the reader in understanding the rationale and utility of a simple quantitative tool which could be used in malocclusion assessment.
Article
A randomized controlled clinical trial was performed to compare the nature, prevalence, intensity, and duration of pain related to the use of a relatively recently developed superelastic arch wire and a more traditional multistranded steel arch wire. Other factors likely to influence the pain experience were also investigated. Forty-three subjects participated in the study, the pain response being assessed by each of the visual analogue scales, the questionnaires, and an analgesic consumption record. In 18 of the 43 subjects a standardized preliminary dental extraction procedure was used as a control. Subsequent to the random allocation of an initial arch wire in 43 patients, 22 of them underwent a second arch wire in the opposing arch, the wire again being determined by random allocation. It was found that the prevalence, intensity, and duration of pain after the insertion of the two types of wire was similar but much greater than in the postextraction control phase. The pain score peaked on the morning after the placement of the arch wire, lasting typically for 5 to 6 days. The pain and discomfort experienced after the insertion of the second arch wire was similar to that of the first, no conditioning response being evident. Overall a diurnal variation was found with a tendency to an increase in pain in the evenings and nights, although this did not greatly affect sleep. The pain response was found to be highly and consistently subjective, not related to the dental arch, crowding, sex, or social class; however, a statistically significant association was found between the age and the pain experienced.
Article
A logical basis for the sequence of wires chosen during orthodontic treatment with fixed appliances is presented. This utilizes a new more realistic model for the radial deflection of a segment of the archwire in which the wire is restrained by the ligatures on the misaligned tooth, contacts the inner edges of the brackets either side, and is restrained by the outer ligatures on these brackets. The model, analysed using simple beam theory, allows the determination of the upper and lower bounds for the range of deflection over which orthodontic forces within the optimum range are produced without distortion for any given wire providing its flexural rigidity (EI) and yield stress in bending (sigma o) are known. The same model can be applied to vertical deflections. Some wire sequences recommended on clinical experience appear to conform to this more pragmatic approach, although to cater for even moderate misalignment the forces predicted by the model are higher than normally considered desirable.
Article
Multivariate analysis of patient characteristics and clinical variables was carried out with the maximum single maxillary incisor apical root resorption for each patient as the dependent variable. Root lengths were measured in standardized intraoral radiographs from 485 consecutively treated patients, 11.5 to 25 years of age. The correlation matrix revealed a complex pattern of positive and negative associations between the six pretreatment and seven treatment variables. Variables found to contribute significantly to apical root resorption were overjet, history of trauma to maxillary incisors before initiation of treatment, time of treatment with rectangular arch wires, time of treatment with Class II elastics, lip/tongue dysfunction, and/or history of finger-sucking habits persisting beyond the age of 7 years, and impacted maxillary canines to be corrected orthodontically. Clinical application of an open activator was significantly correlated with overjet but negatively correlated with apical root resorption, with the use of rectangular arch wires and/or Class II elastics, and with total banding time.
Article
The purpose of this study was to determine the perception of discomfort over time by a group of 70 patients undergoing orthodontic treatment. Patients who were selected for comprehensive orthodontic treatment completed questionnaires before insertion of separators and initial arch wires and after placement at 4 hours, 24 hours, and 7 days. The level of discomfort during these time periods was assessed by a visual analogue scale. The results showed a significant increase in the level of discomfort after insertion of either separators or arch wires at 4 hours and 24 hours, but not at 7 days. No significant difference was found in the level of discomfort of patients more than 16 years of age compared with those 16 years and under. No significant difference in discomfort was found between the sexes. These results are useful in relating expectations of discomfort to patients who undergo orthodontic treatment.
Article
The present study was undertaken to evaluate the long-term status of teeth that had undergone root resorption during active orthodontic treatment. A total of 100 patients who exhibited root resorption during appliance therapy were recalled at a mean period of 14.1 years (SD 0.4) after treatment. At those examinations full-mouth sets of periapical radiographs were taken and tooth mobility evaluated. Pretreatment, posttreatment, and long-term periapical radiographs were examined and compared for changes in root length and contour with time. At each stage scores were given on a scale from 0 to 4, depending on the degree of resorption. The maxillary incisors were affected more frequently and to a greater degree than the rest of the teeth during active treatment. The long-term evaluation showed no apparent changes after appliance removal except remodeling of rough and sharp edges. Hypermobility was observed in only two instances.
Article
Discomfort may accompany orthodontic movement of teeth. The purpose of this study was to determine the time envelope of discomfort induced in young patients (10-16 years) following placement of orthodontic separators and arch wires. Secondly, psychosocial factors concerning feelings of "self" were investigated. Forty-five experimental and 14 control patients seeking orthodontic treatment were included. A data sheet consisting of several visual analogue scales measuring patient perceptions of dental discomfort and psychosocial factors was used. The results indicated that the experimental group experienced significant discomfort with both separators and arch wires at 4 and 24 hr compared to controls; however, the discomfort dissipated by 7 days. The appearance of the teeth and face were significant factors predicting the patient's perspective of "self." The results have significant clinical implications and these are discussed.