Article

The Impact of Canine Retraction on Anchorage Loss in Two Methods of Active Lace Back and NiTi Closed Coil Spring

Abstract and Figures

Introduction:In orthodontics, tooth extraction is required in some cases. Anchorage would be better maintained, if extraction space is done intwo-step andby rewinding the caninein first step alone. Given the importance of anchorage in orthodontics and by considering the contradictions and lack of report of anchorage loss in previous studies, the present study was conducted with aim to compare the active laceback with NiTi coil spring in distalizing the canine and anchorage loss in orthodontic patients requiring extraction of premolars. Materials and methods:In this randomized controlled clinical trial (RCT), which was conducted as split-mouth on the patients referred to orthodontic department of Shahed School of Dentistry in 1395, 15 patients requiringextraction of first maxillarypremolar for treatment were randomly selected. The canine retraction was performed on one side by lace back and on the other side by NiTi coil. After four months, treatment results werecalculated bycomparison with initial measurements. The rotation and tipping of teeth and finally the amount of teeth movement before and after the treatment were calculated. Data were analyzed by SPSS software. Findings: Based on the results, the mean rotation of canine in groups of lace back and NiTi coil were 4.5 and 14.4 degree, respectively, and for molars, this values were 0.55 and 2.3 degree, respectively. The mean tipping of canine in groups of lace back and NiTi coil were 6.25 and 11.45 degree, respectively, and for molar were 1.5 and 5.75 degree, respectively. The mean movement of canine in groups of lace back and NiTi coil were 4.3 and 5.95 mm and for molar were 1.2 and 1.85 mm. Discussion and conclusion:The results ofpresent study showed that canine retraction by lace back is associated with lesser rotation and tipping of the canine and lesser tipping of molar compare to retraction by NiTi coil. The amount and rate of canine and molar movement (anchorage loss) in two techniques had little and insignificant differences.
Content may be subject to copyright.
International Journal of Advanced Biotechnology and Research (IJBR)
ISSN 0976-2612, Online ISSN 2278–599X,
Vol-8, Issue-3, 2017, pp1630-1635
http://www.bipublication.com
Research Article
The Impact of Canine Retraction on Anchorage Loss in Two Methods of Active
Lace Back and NiTi Closed Coil Spring
Mehdi Araghbidikashani1, Amir Hosseinkhatibi2*,
Mohsen Merati,1 Shiva Shivaei Kojoori2,
Mojtaba Sabzijate2, Mohammadreza Badiee4and Tahereh Ghiasian5
1Assistant Professor, Department of Orthodontic, School of dentistry,
Shahed University, Tehran, Iran.
2Postgraduate Student, Department of Orthodontic, School of dentistry,
Shahed University, Tehran, Iran.
4Dentofacial Deformities Research Center, Research Institute of dental Sciences,
ShahidBeheshti University of Medical Sciences, Tehran, Iran.
5Dentist, Private Office, Tehran, Iran.
*Corresponding Author:Amir Hosseinkhatibi
ABSTRACT
Introduction:In orthodontics, tooth extraction is required in some cases. Anchorage would be better maintained, if
extraction space is done intwo-step andby rewinding the caninein first step alone. Given the importance of anchorage
in orthodontics and by considering the contradictions and lack of report of anchorage loss in previous studies, the
present study was conducted with aim to compare the active laceback with NiTi coil spring in distalizing the canine
and anchorage loss in orthodontic patients requiring extraction of premolars.
Materials and methods:In this randomized controlled clinical trial (RCT), which was conducted as split-mouth on
the patients referred to orthodontic department of Shahed School of Dentistry in 1395, 15 patients requiringextraction
of first maxillarypremolar for treatment were randomly selected. The canine retraction was performed on one side by
lace back and on the other side by NiTi coil. After four months, treatment results werecalculated bycomparison with
initial measurements. The rotation and tipping of teeth and finally the amount of teeth movement before and after the
treatment were calculated. Data were analyzed by SPSS software.
Findings: Based on the results, the mean rotation of canine in groups of lace back and NiTi coil were 4.5 and 14.4
degree, respectively, and for molars, this values were 0.55 and 2.3 degree, respectively. The mean tipping of canine in
groups of lace back and NiTi coil were 6.25 and 11.45 degree, respectively, and for molar were 1.5 and 5.75 degree,
respectively. The mean movement of canine in groups of lace back and NiTi coil were 4.3 and 5.95 mm and for molar
were 1.2 and 1.85 mm.
Discussion and conclusion:The results ofpresent study showed that canine retraction by lace back is associated with
lesser rotation and tipping of the canine and lesser tipping of molar compare to retraction by NiTi coil. The amount
and rate of canine and molar movement (anchorage loss) in two techniques had little and insignificant differences.
Keywords: Canine retraction, NiTi closed coil, Active laceback, Anchorage loss
INTRODUCTION:
In orthodontic treatment, teeth extraction is
commonly done for different cases, for example
correcting the severe crowding, rewinding
incisors, molar and canine relationship correction
and improving the facial profile (1). Today,
different methods for canine retraction are used.
Two common methods are using the active
ligatures (or so-called active lace back) and NiTi
coil spring.The use of lace back has been
popularizedbased onMcLaughlin et al. viewpoint
(2). Laceback is extensively used in extraction of
premolars in aligning and leveling step with the
The Impact of Canine Retraction on Anchorage Loss in Two Methods of Active Lace Back and Niti Closed Coil Spring
Mehdi Araghbidikashani, et al. 1631
main objective of canine retraction and creating
space for sorting of anterior teeth. This application
is known as active laceback
(3). Flaws that are mentioned for laceback
aremesial tipping of molar and anchorage loss (4),
which have been also shown in some clinical
studies (5, 6). On the other hand,given that active
ligatures strength slightly reduces over time, NiTi
coil spring has been suggested as an alternative. It
has been reported that NiTi coil spring closes the
extraction space more quickly and more
sustainable (7). The type of the force exerted on
teeth caused by springs and active lace back is
different. NiTi coilsgenerally exert a lighter and
more constant force, while lace back force is
heavier with a short-range. Effectiveness and side
effects of these two techniques of canine
retraction have been compared in only a few
studies (8, 9). Sueri and Turk (2006) conducted a
clinical study entitled “Effectiveness of Laceback
ligatures on Maxillary Canine Retraction” with the
aim to evaluate the effect of lace back ligatures on
canine retraction in teeth aligning and leveling
steps and to compare it with NiTi coils.The results
of their study showed that tipping and rotation of
canine in NiTi coil group were significantly
higher than lace back group. But, the amount of
distalization in NiTi group was significantly
higher than lace back group. The rate of canine
movement in NiTi coil group was also
significantly higher than lace back group. The
anchorage loss (mesial movement of molar) in
NiTi coil group was significantly higher than lace
back group (8).
Normanet al. (2016) conducted a clinical study
entitled “Nickel titanium springs versus stainless
steel springs: A randomized clinical trial of two
methods of space closure” with the aim to
examine effectiveness of NiTi coils in comparison
with stainless steel springs. The results of this
study showed that stainless steel springs not only
have high efficiency for space closure, but they
can also serve better than NiTi coils (9).
Despite reporting of the amount and rate of canine
retraction in both methods, the amount of
anchorage loss in these two methods has not been
reported in previous studies. Given the importance
of anchorage in orthodontics and considering the
contradictions and lack of report of anchorage loss
in previous studies, the present study was
conducted with aim to compare the active
laceback with NiTi coil spring in distalizing the
canine and anchorage loss in orthodontic patients
requiring extraction of premolars.
MATERIALS AND METHODS:
This randomized controlled clinical trial (RCT)
was conducted as split-mouth. The study
population werepatients referred to orthodontic
department of Shahed School of Dentistry in
1395. 15 patients who were candid for removing
of first maxillary premolars for orthodontic
treatment, based on inclusion criteria and
informed consent were enrolled and treated
randomly with split-mouth method. Inclusion
criteria included the need for fixed orthodontic
treatment, the need for first maxillary premolars
for orthodontic treatment, age of 13 to 25 years,
maxillary canine teeth should be grown andall
permanent teeth (excluding third molars) should
be present, and exclusion criteria included
systemic disease affecting the metabolism of bone
and tooth movement, craniofacial syndrome,
pregnancy and consumption of drugs that affect
tooth movement. In the first stage of treatment, for
aligning and leveling the teeth, 14 SS 14, NiTi and
SS 16 wires were used. The step of space
closureof extracted tooth in both methods began at
the beginning of treatment on NiTi 14 wire. Space
closureon each side was performed with lace back
and NiTi coil methods.0.009 inch ligature wire
was used on one side of the mouth for closing the
first molar to canine as active (active lace back).
NiTi closed coil was used on the other side, which
was connected to canine and first molar with
ligature wire. Patients were visited at 4-week
intervals for 4 months. After 4 months, new casts
and panoramic radiographs were obtained from
patientsand to evaluate the amount of rotation,
tipping and movement of canine teeth and molars
in two side of the mouth measured from previous
cast and radiograph before treatment of patient
were compared. To measure the rotation of teeth,
the angle of the line connecting mesial and
The Impact of Canine Retraction on Anchorage Loss in Two Methods of Active Lace Back and Niti Closed Coil Spring
Mehdi Araghbidikashani, et al. 1632
distalheight of contourof canine and molar teeth
with midpalatal raphe in casts before and after the
treatmentwas measured. Then, tooth tipping was
measured by measuring the angle of the line
connecting cusp tip of canine to the tip of the root
of this tooth with the line connecting the most
inferior point of orbits (infraorbital line) in
radiography, and the movement of the tooth was
measured by measuring the distance of cusp tip of
canine and mesiobuccal tip of first molar with line
perpendicular to the midpalatal raphe at first
rogay.. To measure the tipping of the first molar,
the angle of the line connecting the mesial cusp
tips to tip of the palatal root of this tooth with
infraorbital line in panoramic radiographwas
measured. (figure 1, 2, 3). The information
obtained from measurements on radiographyand
dental casts before and after treatment were
recorded and analyzed by SPSS software.
Figure 1.Measuring the angle of canine relative to the midpalatal raphe
The Impact of Canine Retraction on Anchorage Loss in Two Methods of Active Lace Back and Niti Closed Coil Spring
Mehdi Araghbidikashani, et al. 1633
Figure 2. Measuring the angle of molar relative to midpalatal raphe (the blue line is drawn parallel to the yellow line
(mesiodistal molar)
Figure 3.Measuring the distance of teeth relative to midpalatal raphe perpendicular at first rogay.
FINDINGS:
In this study, 15 patients (6 males and 9 females) were enrolled with average age of 14.3 ± 5.6. Table 1
shows the rotation of canine and molar teeth in two techniques used. The rotation range of canine in lace
back group was between -10 and 0 degrees and in NiTi coil group was between -42 and –7 degrees andfor
molar, the rotation range of tooth in lace back group was between -6 and 5 degrees and in NiTi coil group
was between -8 and 10 degrees. As shown in Figure 5, the rotation of canine in NiTi coil group was more
than lace back group (P=0.005), but this difference was not significant for rotation of molar (p = 0.359).
Table 1.The amount of canine and molar teeth rotation in both methods used
Lace back
NiTi coil
The mean
Standard deviation
The mean
Standard deviation
The Impact of Canine Retraction on Anchorage Loss in Two Methods of Active Lace Back and Niti Closed Coil Spring
Mehdi Araghbidikashani, et al. 1634
Canine
-
4.50
3.44
-
14.40
11.02
0.005
molar
0.55
3.04
2.30
6.22
0.359
The results showed that tipping range of canine in lace back group was between 0 and 10 degrees and in
NiTi coil group was between 1 and 19 degrees. For molar tooth, tipping range of tooth in lace back group
was between -15 and 5.5 degrees and in NiTi coil group was between -17 and 2.5 degrees. As shown in
Figure 6, the amount of canine and molar tipping in NiTi coil group was more than lace back group
(P<0.05).
Table 2. The amount of canine and molar teeth tipping in both methods used
Lace back
NiTi coil
The mean
Standard deviation
The mean
Standard deviation
Canine
6.25
3.40
11.45
5.01
0.028
molar
-
1.50
5.75
-
5.75
6.20
0.046
Based on the results of the study, the movement range of canine in lace back group was between 1.5 and
10.5 mm and in NiTi group was between 5 and 8.5 mm. For molar tooth, the movement range of tooth in
lace back group was between 0.5 and 2 mm and in NiTi coil group was 0 and 5.5 mm. As shown in Figure
7, The amount of the movement of canine and molar in NiTi coil group and lace back group was not
significant (P>0.05).
Table 3.The movement of canine and molar teeth in two methods used
Lace back
NiTi coil
The mean
Standard deviation
The mean
Standard deviation
Canine
4.30
3.27
5.95
1.19
0.239
molar
1.20
0.48
1.85
1.76
0.438
Finally, the average rate of canine movement in
lace back group was 1.075 ± 0.82 mm per month
(range of 2.63 and 0.37) and in NiTi coil group
was 1.49 ± 0.30 mm per month (range of 2.12 and
1.25). Based on statistical analysis, this difference
was not significant (p = 0.239).
DISCUSSION AND CONCLUSION:
This study was a randomized clinical trial with a
split-mouth design to evaluate and compare the
effectiveness of active ligatures (Lace back) and
NiTi coil for canine retraction. In the present
study, in the group that canine retraction was done
by NiTi coil, canine rotation was 14.4 degree
(mesiobuccalrotation), canine tipping was 11.45
degree (distal tip), and the mean movement of
canine was 5.95 mm (the rate of 1.49 mm per
month). Also, the amount of anchorage loss in this
group was 1.85 mm. In the study by Samuels et al.
(1998) (10) on 18 patients, it was shown that
average rate of canine retraction by NiTi with
150g forceis 0.16 mm per week. In the study by
Nightingate and Jones (2003) (11), the average
rate of canine retraction in 22 patients by NiTi coil
with the force of 149-300g was 0.21 mm per
week. In the study by Cacciafesta et al. (2003)
(12), the average rate of canine retraction by NiTi
coil with the rate of 1 Newton in 8 patients was
1.41 mm. In the present study, in the group that
canine retraction had been done by lace back,
canine rotation was 4.5 degree (mesiobuccal
rotation), canine tipping was 6.25 degree (distal
tip), and the average movement of canine in four
months was 4.3 mm (rate of 1.07 mm per month).
Also, the amount of anchorage loss in this group
was1.2 mm. Chetan et al. in a RCT study on 20
patients who needed extraction of first maxillary
premolar tooth, they showed that incanine
retraction by lace back within three months,
canine moves distal 1.74 mm (0.58 mm per
month). In this study also has been showed that
average canine rotation within three months was 5
degree and average tipping of it was 5.9 degree
(13). In this study, canine retraction by lace back
was associated with lesser rotation and tipping of
the canine and lesser tipping of the molar compare
The Impact of Canine Retraction on Anchorage Loss in Two Methods of Active Lace Back and Niti Closed Coil Spring
Mehdi Araghbidikashani, et al. 1635
to retraction by NiTi coil. The amount and rate of
canine and molar movement (anchorage loss) in
these two techniques had little and insignificant
differences. Despite the results of present study,
Dixon et al. (7) in a RCT study,compared thethree
methods of space closureincluding active ligatures
(lace back), polyurethane powerchains and nickel
titanium coils, they showed that the rate of space
closure by NiTi is more than lace back. In this
study, 33 patients were enrolled and randomly
received one of the methods ofspace closure. The
results of the study showed that the rate of space
closureby lace back was 0.35 mm per month, by
powerchain was 0.58 mm per month and by NiTi
coil was 0.81 mm per month. Based on statistical
analysis, the rate of space closureby NiTi was
significantly higher than the rate of space
closureby lace back (7). In a laboratory study,
regardless of PDL and dental movement and the
role it might have on reducing the force, they
compare and calculated the loss of strength in
active ligature and NiTi coil over time (14). The
results ofthat study showed that more than half of
the lace back strength loses after 4 weeks, while
NiTi coil showed no loss of strength over time
(14). Overall, the resultsof the present study
showed that canine retractionby lace back is
associated with lesser tipping and rotation of the
canine and lesser tipping of the molar compare to
retraction by NiTi coil. The amount and rate of
canine and molar movement (anchorage loss) in
two techniques had less and no significant
differences.
REFERENCE:
1. Sharma R, Mittal AK, Sidana A, Tiwari P.
Canine retraction in orthodontics: a review of
various methods. Med Res Chron;2:85-93
2. McLaughlin RP, Bennett JC, Trevisi HJ.
Systemised Orthodontic Treatment Mechanics.
Mosby, Edinburgh, 2001: 101–2.
3. Moresca RC, Vigorito JW, Dominguez GC,
Tortamano A, Moraes DR, Moro A, et al.
Effects of active and passive lacebacks on
antero-posterior position of maxillary first
molars and central incisors. Braz Dent J
2012;23:433-7.
4. Fleming PS, Johal A, Pandis N. The
effectiveness of laceback ligatures during
initial orthodontic alignment: a systematic
review and meta-analysis. Eur J Orthod
2013;35:539-46
5. Irvine R, Power S, McDonald F. The
effectiveness of laceback ligatures: a
randomized controlled clinical trial. J Orthod
2004;31:303-311.
6. MorescaRC,Vigorito JW, Dominguez GC,
TortamanoA,Moraes DR, Moro A, Correr GM.
Effects of Active and Passive Lacebacks on
Antero-Posterior Position of Maxillary First
Molars and Central Incisors. Braz Dent J.
2012; 23: 433-437. .
7. Dixon V, Read MJ, O'Brien KD, Worthington
HV, Mandall NA. A randomized clinical trial
to compare three methods of orthodontic space
closure. J Orthod 2002;29:31-6
8. Sueri MY, Turk T. Effectiveness of laceback
ligatures on maxillary canine retraction. Angle
Orthod 2006;76:1010-4.
9. Norman NH, Worthington H, Chadwick SM.
Nickel titanium springs versus stainless steel
springs: A randomized clinical trial of two
methods of space closure. J Orthod
2016;43:176-85.
10. Samuels RH, Rudge SJ, Mair LH. A clinical
study of space closure with nickel-titanium
closed coil springs and an elastic module. Am J
OrthodDentofacialOrthop 1998;114:73-9.
11. Nightingale C, Jones SP. A clinical
investigation of force delivery systems for
orthodontic space closure. J Orthod
2003;30:229-36
12. Cacciafesta V, Sfondrini MF, Ricciardi A,
Scribante A, Klersy C, Auricchio F. Evaluation
of friction of stainless steel and esthetic self-
ligating brackets in various bracket-archwire
combinations. Am J OrthodDentofacialOrthop
2003;124:395-402.
13. BR GK, Shamnur N, Singhvi A. Individual
canine retraction: RCT comparing Mulligan
bypasses arch and Active laceback ligatures.
IOSR Journal of Dental and Medical Sciences
(IOSR-JDMS);1:34-7
The Impact of Canine Retraction on Anchorage Loss in Two Methods of Active Lace Back and Niti Closed Coil Spring
Mehdi Araghbidikashani, et al. 1636
14. Steiger P. In vitro comparison of force decay
between three orthodontic sliding retraction
methods. Nova Southeastern University -
Master thesis 2014
ResearchGate has not been able to resolve any citations for this publication.
Article
Full-text available
Objective: To compare the clinical performance of nickel titanium (NiTi) versus stainless steel (SS) springs during orthodontic space closure. Design: Two-centre parallel group randomized clinical trial. Setting: Orthodontic Department University of Manchester Dental Hospital and Orthodontic Department Countess of Chester Hospital, United Kingdom. Subjects and methods: Forty orthodontic patients requiring fixed appliance treatment were enrolled, each being randomly allocated into either NiTi (n = 19) or SS groups (n = 21). Study models were constructed at the start of the space closure phase (T0) and following the completion of space closure (T1). The rate of space closure achieved for each patient was calculated by taking an average measurement from the tip of the canine to the mesiobuccal groove on the first permanent molar of each quadrant. Results: The study was terminated early due to time constraints. Only 30 patients completed, 15 in each study group. There was no statistically significant difference between the amounts of space closed (mean difference 0.17 mm (95%CI -0.99 to 1.34; P = 0.76)). The mean rate of space closure for NiTi coil springs was 0.58 mm/4 weeks (SD 0.24) and 0.85 mm/4 weeks (SD 0.36) for the stainless steel springs. There was a statistically significant difference between the two groups (P = 0.024), in favour of the stainless steel springs, when the mean values per patient were compared. Conclusions: Our study shows that stainless steel springs are clinically effective; these springs produce as much space closure as their more expensive rivals, the NiTi springs.
Article
Full-text available
The purpose of this study was to compare the effects of active and passive lacebacks on antero-posterior position of maxillary first molars and central incisors during leveling phase. Twenty-three subjects with Class I and Class II malocclusion were treated with first premolars extraction using preadjusted appliances (MBT 0.022-inch brackets). The leveling phase was performed with stainless steel archwires only. The sample was divided into 2 groups: 14 subjects received active lacebacks (Group 1) and 9 subjects received passive lacebacks (Group 2). Lacebacks were made from 0.008-inch ligature wire. Lateral cephalometric radiographs were taken pre- and post-leveling phase. Student's t-test was applied to determine the differences between pre- and post-leveling mean values and to determine the mean differences between groups. In Group I, the first molars showed a significant mesial movement, whereas no change was observed in Group 2. In both groups, maxillary central incisor crowns moved to lingual side. In conclusion, active laceback produced anchorage loss of maxillary first molars whereas passive laceback did not affect the position of these teeth. Active and passive lacebacks were effective in preventing central incisor proclination.
Article
Full-text available
Lacebacks may be used to limit unwanted incisor proclination during initial orthodontic alignment; however, their use has not met with universal approval. This systematic review aims to appraise the evidence in relation to the effectiveness of lacebacks in controlling incisor position during initial alignment. Electronic database searches of published literature (MEDLINE via Ovid, Cochrane Central Register of Controlled Trials, LILACS, and IBECS) and unpublished literature were performed. Search terms used included randomized controlled trial, controlled clinical trial, random allocation, double blind method, orthodontics, and laceback. Data were extracted using custom forms. Risk of bias assessment was made using the Cochrane Collaboration risk of bias tool. The quality of the evidence was also assessed using GRADE. Mean differences in incisor inclination and antero-posterior changes in incisor and molar position during alignment were calculated. Two studies involving 97 participants were found to be at low risk of bias and were included in the quantitative synthesis. The random effects meta-analysis demonstrated that the use of lacebacks was associated with 0.5 mm greater posterior movement of the incisors during alignment; this finding was of limited clinical importance and statistically non-significant [95 per cent confidence interval (CI): -1.25, 0.25, P = 0.19]. Little difference (0.46 mm) was also found between laceback and non-laceback groups with regards to mesial molar movement (95 per cent CI: -0.33, 1.24, P = 0.26). According to the GRADE assessment, the overall quality of evidence relating to the use of lacebacks was high. There is no evidence to support the use of lacebacks for the control of the sagittal position of the incisors during initial orthodontic alignment.
Article
Full-text available
To compare the rates of orthodontic space closure for: Active ligatures, polyurethane powerchain (Rocky Mountain Orthodontics, RMO Europe, Parc d'Innovation, Rue Geiler de Kaysersberg, 67400 Illkirch-Graffenstaden, Strasbourg, France) and nickel titanium springs. Patients entering the space closure phase of fixed orthodontic treatment attending six orthodontic providers. Twelve patients received active ligatures (48 quadrants), 10 patients received powerchain (40 quadrants) and 11 patients, nickel-titanium springs (44 quadrants). Patients were randomly allocated for treatment with active ligatures, powerchain or nickel titanium springs. Upper and lower study models were collected at the start of space closure (T(o)) and 4 months later (T(1)). We recorded whether the patient wore Class II or Class III elastics. Space present in all four quadrants was measured, by a calibrated examiner, using Vernier callipers at T(o) and T(1.) The rate of space closure, in millimetres per month (4 weeks) and a 4-monthly rate, was then calculated. Examiner reliability was assessed at least 2 weeks later. Mean rates of space closure were 0.35 mm/month for active ligatures, 0.58 mm/month for powerchain, and 0.81 mm/month for NiTi springs. No statistically significant differences were found between any methods with the exception of NiTi springs showing more rapid space closure than active ligatures (P < 0.05). There was no effect of inter-arch elastics on rate of space closure. NiTi springs gave the most rapid rate of space closure and may be considered the treatment of choice. However, powerchain provides a cheaper treatment option that is as effective. The use of inter-arch elastics does not appear to influence rate of space closure.
Article
Full-text available
To evaluate the effects of laceback ligatures on the anteroposterior and vertical position of lower incisors and the mesial position of the lower first molars. Randomized controlled trial. Patients under treatment in the Department of Orthodontics, Royal Bournemouth Hospital, Dorset, during a 6 month period from November 1999 to March 2000. Sixty-two adolescents (mean 13.7 years, range 11.2-16.8 years) with similar malocclusions, requiring extraction of all first premolars, were randomly assigned to experimental (laceback: 30; 12 male, 18 female) and control (non-laceback: 32; 14 male, 18 female) groups. Treatment using upper and lower fixed appliances following extraction of four premolars. One group had lacebacks placed, whilst the control group had no lacebacks. The participants were examined clinically and radiographically, and lateral cephalograms with radio-opaque tooth markers and lower study casts records were taken when lower fixed appliances were placed (T1) and following sufficient leveling with a 0.018 inch stainless steel round wire (T2). Linear measurements were recorded following digitization of the lateral cephalograms and using a vernier caliper on the study casts. A Student t-test was used to examine differences between the two groups following assessment for normality. In both groups the lower incisors retroclined during T1-T2; (Mean+/-SD: Experimental -0.53+/-1.9 mm, Control -0.44+/-1.29 mm). There was no statistical significance between the two groups (p = 0.84). The lower incisors extruded in both groups; 0.47+/-0.98 mm in the experimental group and 0.44+/-0.87 mm in the control group. There was no statistical difference between the groups (p = 0.9). The lower first molars showed 0.83 mm greater mesial movement in the experimental group, which was statistically significant (p < 0.05). Labial segment crowding decreased in both groups (experimental -3+/-1.6 mm, control -2.67+/-2.28 mm), the difference between the groups being non-significant (p = 0.51). Arch length decreased in both groups (experimental -2.08+/-2.82 mm , control -2.9+/-3.06 mm), but the difference between them was not significant (p = 0.28) In first premolar extraction cases, the lower labial segment does not procline during the leveling stage with the pre-adjusted edgewise appliance and the use of laceback ligatures conveys no difference in the anteroposterior or vertical position of the lower labial segment. Furthermore, the use of laceback ligatures creates a statistically and clinically significant increase in the loss of posterior anchorage.
Article
Full-text available
To evaluate the effects of laceback ligatures on canine distalization during the leveling and aligning stage and to compare the effectiveness of laceback ligatures with that of superelastic NiTi closed coil springs. Fifteen subjects were included in this study. Fixed orthodontic treatment was planned with the extraction of first premolars to solve crowding in upper and/or lower arches. Stainless steel direct-bonding Roth brackets (0.022-inch) were used. For canine distalization superelastic NiTi closed coil springs generating 150 g of force were used on one side. Lacebacks made from 0.010-inch ligature wire were applied on the contralateral side. Dental and skeletal changes were evaluated from predistalization and postdistalization lateral cephalometric and submento vertical radiographs. A Wilcoxon test was applied to determine the differences between predistalization and postdistalization mean values and to determine the mean differences between the groups. Upper incisor crowns moved posteriorly. Distal movement and tipping of the canines were significant for both groups. Likewise, mesial movement and tipping of the first molars were significant for both groups. Furthermore, distopalatinal rotation of the canines was significant in the coil group. Canine and molar movements were greater for the coil group than for the laceback group, and the differences were significant. These differences may be attributed to force characterization, as well as to arch wire size and material. The laceback ligatures proved to be effective for canine distalization. Less canine and molar movement was found for the laceback group, but more controlled movements were obtained for the sagittal, vertical, and transverse planes.
Article
A previous study has shown that a 150-gram nickel-titanium closed coil spring (Sentalloy, GAC International Inc.) closed spaces more quickly and more consistently than an elastic module (Alastik, Unitec/3M). This study used the same friction sensitive sliding mechanics of pitting the six anterior teeth against the second bicuspid and first molars, to examine the rate of space closure of 100-gram and 200-gram nickel-titanium closed coil springs. The results for the three springs and elastic module were compared. The nickel-titanium closed coil springs produced a more consistent space closure than the elastic module. The 150- and 200-gram springs produced a faster rate of space closure than the elastic module or the 100-gram spring. No significant difference was noted between the rates of closure for the 150- and the 200-gram springs.
Article
To investigate the force retention, and rates of space closure achieved by elastomeric chain and nickel titanium coil springs. Randomized clinical trial. Eastman Dental Hospital, London and Queen Mary's University Hospital, Roehampton, 1998-2000. Subjects, materials and methods: Twenty-two orthodontic patients, wearing the pre-adjusted edgewise appliance undergoing space closure in opposing quadrants, using sliding mechanics on 0.019 x 0.025-inch posted stainless steel archwires. Medium-spaced elastomeric chain [Durachain, OrthoCare (UK) Ltd., Bradford, UK] and 9-mm nickel titanium coil springs [OrthoCare (UK) Ltd.] were placed in opposing quadrants for 15 patients. Elastomeric chain only was used in a further seven patients. The initial forces on placement and residual forces at the subsequent visit were measured with a dial push-pull gauge [Orthocare (UK) Ltd]. Study models of eight patients were taken before and after space closure, from which measurements were made to establish mean space closure. The forces were measured in grammes and space closure in millimetres. Fifty-nine per cent (31/53) of the elastomeric sample maintained at least 50 per cent of the initial force over a time period of 1-15 weeks. No sample lost all its force, and the mean loss was 47 per cent (range: 0-76 per cent). Nickel titanium coil springs lost force rapidly over 6 weeks, following that force levels plateaued. Forty-six per cent (12/26) maintained at least 50 per cent of their initial force over a time period of 1-22 weeks, and mean force loss was 48 per cent (range: 12-68 per cent). The rate of mean weekly space closure for elastomeric chain was 0.21 mm and for nickel titanium coil springs 0.26 mm. There was no relationship between the initial force applied and rate of space closure. None of the sample failed during the study period giving a 100 per cent response rate. In clinical use, the force retention of elastomeric chain was better than previously concluded. High initial forces resulted in high force decay. Nickel titanium coil springs and elastomeric chain closed spaces at a similar rate.
Article
This study measured and compared the level of frictional resistance generated between stainless steel self-ligating brackets (Damon SL II, SDS Ormco, Glendora, Calif), polycarbonate self-ligating brackets (Oyster, Gestenco International, Göthenburg, Sweden), and conventional stainless steel brackets (Victory Series, 3M Unitek, Monrovia, Calif), and 3 different orthodontic wire alloys: stainless steel (Stainless Steel, SDS Ormco), nickel-titanium (Ni-Ti, SDS Ormco), and beta-titanium (TMA, SDS Ormco). All brackets had a.022-in slot, whereas the orthodontic wire alloys were tested in 3 different sections:.016,.017 x.025, and.019 x 0.025 in. Each of the 27 bracket and archwire combinations was tested 10 times, and each test was performed with a new bracket-wire sample. Both static and kinetic friction were measured on a custom-designed apparatus. All data were statistically analyzed (Kruskal-Wallis and Mann Whitney U tests). Stainless steel self-ligating brackets generated significantly lower static and kinetic frictional forces than both conventional stainless steel and polycarbonate self-ligating brackets, which showed no significant differences between them. Beta-titanium archwires had higher frictional resistances than stainless steel and nickel-titanium archwires. No significant differences were found between stainless steel and nickel-titanium archwires. All brackets showed higher static and kinetic frictional forces as the wire size increased.