Stabilité chromatique et dégradation de la force de chaînettes élastomériques orthodontiques transparentes : une étude in vitro

ORTHO 175 1-15 Ó 2015 CEO Published by / E´dite´ par Elsevier Masson SAS All rights reserved / Tous droits re´serve´s

Original Article Article original

Color stability and force decay of clear orthodontic elastomeric chains: An in vitro study
chromatique et de
gradation de la force Stabilite
lastome
riques orthodontiques de chaıˆnettes e
tude in vitro transparentes : une e Abdullah M. ALDREESa,*, Sahal A. AL-FORAIDIb, Mohammed S. MURAYSHEDc, Khalid A. ALMOAMMARa a

Division of Orthodontics, Department of Pediatric Dentistry and Orthodontics, College of Dentistry, King Saud University, P.O. Box 60169-38, Riyadh 11545, Saudi Arabia b Department of Pediatric Dentistry and Orthodontics, College of Dentistry, Taibah University, AlMadinah AlMonawarah, Saudi Arabia c Department of Prosthetic Dental Sciences, College of Dentistry, Sattam bin Abdulaziz University, AlKharj, Saudi Arabia Available online: XXX / Disponible en ligne : XXX

Summary


sume
Re

Objective: To compare the percentage force decay of clear and semi-clear elastomeric chain products from eight different manufacturers and to evaluate the amount of discoloration after immersion in colored dietary media of the same elastomeric chain products.


Objectif : Comparer le pourcentage de degradation de force

eriques transparentes et semi-transde chaînettes elastom

parentes provenant de huit fabricants differents et evaluer le
 immersion dans des substances degre
de decoloration, apres
^ alimentaires colorees, de ces memes chaînettes

elastom eriques.



e
con¸c ue Materiaux et methodes : Une etude in vitro a et
utilisant une jauge de force electronique pour mesurer six
echantillons de chacun des 19 types de chaînette



es
pendant une periode
elastom erique qui etaient etir de 4  a mesure
la teinte de chasemaines. Un spectrophotometre


que echantillon (10 de chaque type) au depart de l’etude et  immersion pendant 72 heures dans une substance aliapres
the,
cola, ou vin [250 mL de chaque]). mentaire (cafe,

Resultats : Il y avait une difference significative du pourcentage de force initiale perdue entre toutes les chaînettes
(p < 0,001). L’ANOVA a rev
el
e
une difference
testees signif

icative de degre
de decoloration entre les differents types de chaînettes (p < 0,001). Les types de chaînettes semitransparentes (couleur dent, perle, obscure ; TP-ToothC,
OrthO-Pearl, GAC-SiliPearl, 3M-Obscure) presentaient

Material and methods: An in vitro study was designed using an electronic force gauge to measure six samples from each of 19 types of elastomeric chains stretched for a period of four weeks. A spectrophotometer was used to measure the color of each specimen (10 of each type) at baseline and after being soaked in a dietary medium (coffee, tea, cola, and wine in 250 ml amounts) for 72 h. Results: There was a significant difference in the percentage of the lost initial force between all the tested E-chains (P < 0.001). ANOVA shows a significant difference in the amount of discoloration between the E-chain types (P < 0.001). Semi-clear (tooth-color/pearl/obscure) E-chain types (TP-ToothC, OrthO-Pearl, GAC-SiliPearl, 3M-Obscure) present significantly less change in color than clear E-chains of

Correspondence and reprints / Correspondance et tire
s a` part. e-mail address / Adresse e-mail : [email protected] (Abdullah M. Aldrees) *

International Orthodontics 2015 ; X : 1-15 http://dx.doi.org/10.1016/j.ortho.2015.06.003

1

ORTHO 175 1-15

Abdullah M. ALDREES et al.

Ó 2015 CEO. Published by Elsevier Masson SAS. All rights reserved


significativement moins d’alteration chromatique que les ^ marque (TP-Clear, chaînettes transparentes de la meme OrthoO-Clear, GAC-SiliClear, 3M-Clear).
Conclusions : Des differences significatives de pourcentage

e
observees
entre les moyen de la degradation de force ont et

Les chaînettes 19 types de chaînette transparente etudi es. AO-Memory et Ormco ont conserve
la plupart de leur force
initiale au bout de la periode de quatre semaines. Des



e
differences significatives de decoloration ont egalement et
entre les divers types de chaînette. TP Orthodontics notees (couleur de dent, SuperSlick, Transparente) et Ortho
Organizers (perle) ont subi le moins de decoloration. Ó 2015 CEO. E´dite´ par Elsevier Masson SAS. Tous droits re´serve´s

Key-words


s Mots-cle

the same brand (TP-Clear, OrthoO-Clear, GAC-SiliClear, 3MClear). Conclusions: Significant differences in the mean percentage force decay between the 19 studied clear elastomeric chain types were present. AO-Memory and Ormco maintained most of their original force at the end of the four-week interval. Significant differences in discoloration also exist between the various types of E-chains. TP Orthodontics (Tooth-Colored, SuperSlick, Clear) and Ortho Organizers (Pearl) showed the least discoloration.

·· ·

Elastomeric chain. Color stability. Force decay.

·· ·


lastome
rique. Chaıˆnette e
chromatique. Stabilite
gradation de force. De

Introduction

Introduction

There is greater awareness of, and demand for, orthodontic treatment for adults. This has led to an increase in the demand for more esthetically pleasing orthodontic appliances. Orthodontic treatment has the ability to modify the dentofacial skeleton and affect facial esthetics, and currently many adult patients seek orthodontic treatment for their malocclusions. In a recent Medical Expenditure Panel Survey (MEPS), adults accounted for 23.1% of all orthodontic visits in 2004 [1]. In 2008, in the fifth study of orthodontic and treatment procedures, it was demonstrated that adults constituted 20% of all orthodontic patients in the United States [2]. Orthodontists and adult patients alike have developed a more discerning eye and preference for more esthetic braces. Clear orthodontic brackets have become available for clinical use in the last 30 years as esthetic choices in spite of several negative clinical properties [3].

Parmi la population adulte, la prise de conscience des possi
s du traitement orthodontique s’est fortement accrue, bilite donnant lieu a` une demande croissante pour des appareils
tiques. Le traitement orthodontique a la orthodontiques esthe
de modifier le squelette dentofacial et d’influer sur capacite
tique du visage et de nombreux patients adultes l’esthe recherchent une solution orthodontique pour corriger leurs
cent du Medical malocclusions. Dans un sondage re
Expenditure Panel (MEPS) aux Etats-Unis, les adultes
sentaient 23,1 % de toutes les consultations orthodonrepre me enque ^te sur tiques en 2004 [1]. En 2008, dans leur cinquie
dures de traitement orthodontiques, Keim et al. ont les proce
que les adultes constituaient 20 % de tous les rapporte
patients orthodontiques aux Etats-Unis [2]. Les patients
veloppe
adultes et les praticiens orthodontiques ont tous de
fe
rence pour les appareils un regard plus averti et une pre
tiques. Depuis une trentaine orthodontiques plus esthe
es, les brackets transparents sont utilise
s en clinique d’anne
s esthe
tiques, et cela malgre
pluen raison de leurs qualite
ristiques cliniques ne
gatives [3]. sieurs caracte
lastome
riques sont utilise
s courLes chaıˆnettes et modules e amment en orthodontie depuis leur introduction il y a 35 ans [4].
s Ces chaıˆnettes et anneau de ligatures simples sont fabrique
te
s et sont disponibles dans une par de nombreuses socie
te
de teintes pour satisfaire a` la demande mondiale pour varie
tiques. Les chaıˆnettes des appareils orthodontiques esthe
lastome
riques sont fabrique
es en polyorthodontiques e
thane utilisant un processus d’estampage ou de moulage ure
de
d’estampage comporte deux par injection [5]. Le proce
tapes : d’abord un processus d’extrusion pour produire des e res de polyure
thane. Ensuite, l’estampeur de
coupe feuilles entie
finitives. les feuilles pour obtenir la forme et les dimensions de

Elastomeric modules and chains have been common features of orthodontic practice since their introduction more than 35 years ago [4]. These chains and single ligatures are manufactured by many companies and are available in a variety of different colors to meet the growing global demand for esthetic orthodontic appliances. Orthodontic elastomeric chains are made from polyurethane using a die-stamping or injectionmolding process [5]. The die-stamping process consists of two steps: the first uses an extrusion process to produce bulk sheets of polyurethane. In the second, the die stamp cuts the sheet into the final shape and size.

2

International Orthodontics 2015 ; X : 1-15

ORTHO 175 1-15

Color stability and force decay of clear orthodontic elastomeric chains: An in vitro study


chromatique et de
gradation de la force de chaıˆnettes e
lastome
riques orthodontiques transparentes : une e
tude in vitro Stabilite

The use of clear elastomeric chains to move the teeth along the archwire has improved the esthetic aspect of clear orthodontic fixed appliances. However, elastomeric chains are subject to discoloration if patients consume certain foods or beverages, such as coffee and tea, between appointments [6]. This leads to esthetic problems, particularly considering that ceramic brackets are stain-resistant, as opposed to the elastomeric chains that are discolored by certain foods with a high staining potential. Concerns have been raised regarding the quality of the products and whether one company is superior to another in efficacy or cost-effectiveness. Although elastomeric products have been reported to be susceptible to staining in the oral environment, only two systematic studies on color stability of elastomeric modules have been reported [7,8]. Ardeshna and Vaidyanathan measured color changes in both colored and clear orthodontic elastomeric modules produced by four different companies after being soaked in coffee, cola, tea and spices for 72 hours, with a Minolta chromameter. Significant color changes were observed resulting from exposure to beverages and spices, which included gray level and chromaticity. Module resistance to color changes differed based on the method of manufacturing. For example, modules made by extrusion suffered from color changes more than modules made by injecting moldings [7]. Kim and Lee investigated the change in the color of three types of clear orthodontic elastomeric modules after immersion in 2% methylene blue from a few hours up to five days using digital images and commercial software. They found significant differences in discoloration depending on different factors including the immersion solution type and duration, as well as the type of modules [8].

There is general agreement that elastomeric module discoloration may affect the esthetics of orthodontic appliances, such as ceramic brackets. However, this aspect has not been evaluated in previous studies. In addition, spectrophotometry is commonly used for evaluating surface color. It is accurate and reliable in attaining these measurements [9], but was never used to evaluate the discoloration of orthodontic modules. Manufacturers have also produced semi-clear orthodontic modules that tend to show less change in color between appointments. These modules have not been assessed and compared with clear modules. Elastomeric chains appear to undergo permanent elongation after three or four weeks in the mouth [10]. Alastik chains lose 74% of their initial force within 24 hours [10]. Wong agreed with this figure, and added that the reduction was greatest during the first three hours [6]. Hershey and Reynolds found

International Orthodontics 2015 ; X : 1-15


lastome
riques pour de
placer les L’utilisation de chaıˆnettes e
liore
l’aspect esthe
tique des appareils dents sur le fil a ame orthodontiques fixes transparents. Cependant, les chaıˆnettes
lastome
riques sont sujettes a` la de
coloration si les patients e
consomment certains aliments ou breuvages, tels que le cafe
, entre deux rendez-vous [6]. Cette situation ge
ne re ou le the mes esthe
tiques, surtout e
tant donne
que les des proble
ramiques sont re
sistants aux taches par oppobrackets en ce
lastome
riques qui subissent une alte
rasition aux chaıˆnettes e
rise
s tion de leur teinte au contact de certains aliments caracte par leur fort potentiel de coloration.
te
exprime
s quant a` la qualite
de ces produits Des soucis ont e
s si un fabricant e
tait et certains auteurs se sont demande
rieur a` d’autres en termes d’efficacite
ou de rapport supe
. Malgre
les rapports concernant la suscouˆt-efficacite
des produits e
lastome
riques aux taches dans le ceptibilite
tudes syste
matiques sur la stabilite
milieu oral, seules deux e
lastome
riques ont e
te
publie
es de la couleur des modules e
les changements [7,8]. Ardeshna et Vaidyanathan ont mesure
lastome
riques orthodontiques aussi de teinte des modules e
s que transparents fabrique
s par quatre socie
te
s bien colore
rentes apre s immersion dans du cafe
, du cola, du the
ou diffe
pices pendant 72 heures, utilisant un chromame tre des e Minolta. Des changements de teintes significatifs, comprenant
, ont e
te
observe
s suite le niveau de gris et la chromaticite
pices. La re
sistance a` l’exposition aux breuvages et aux e
ration de couleur a varie
selon la me
thode des modules a` l’alte
s par extrude fabrication. Par exemple, les modules fabrique sion ont subi des modifications plus importantes que les mod
s par injection de moulure [7]. Kim et Lee ont ules fabrique
tudie
les changements de teinte de trois types de modules e
lastome
riques orthodontiques transparents apre s immersion e
thyle ne a` 2 % pendant des pe
riodes allant dans du bleu de me
riques de plusieurs heures a` 5 jours utilisant des images nume
des diffe
rences de et un logiciel commercial. Ils ont trouve
coloration significatives en fonction de divers facteurs, dont de
e, la dure
e de l’immersion et le type de modla solution utilise ule [8].
ment admis que la de
coloration des modules Il est commune
lastome
riques peut influer sur l’esthe
tique des appareils e
ramique. orthodontiques tels que les brackets en ce
anmoins, ce phe
nome ne n’a jamais e
te
e
value
dans Ne
tudes ante
rieures. De plus, la spectrophotome
trie est les e
e pour e
valuer la teinte des surfaces. Il couramment utilise
cise et fiable pour calculer ces s’agit d’une technique pre
te
exploite
e pour e
valuer la mesures [9] mais qui n’a jamais e
coloration des modules orthodontiques. Les fabricants ont de
galement produit des modules orthodontiques semi-transe
ve
ler les changements parents qui ont tendance a` moins re
te
de teinte entre deux rendez-vous. Ces modules n’ont pas e
value
s ou compare
s avec les modules transparents. e
lastome
riques semblent subir une e
longation Les chaıˆnettes e s trois ou quatre semaines dans la bouche permanente apre [10]. Les chaıˆnettes Alastik perdent 74 % de leur force initiale
ce chiffre et a ajoute
que en 24 heures [10]. Wong a confirme
duction e
tait la plus forte pendant les trois premie res la re

3

ORTHO 175 1-15

Abdullah M. ALDREES et al.

that after four weeks, the elastomeric chain modules retained only about 40% of their original force [4]. Moreover, it has been reported that, after 21 days, elastomeric modules with higher initial forces (short modules) underwent less force decay than elastomeric modules with lower initial force values (long modules) [11]. Lu et al. observed that the most force decay occurred when the initial force was high and also, the greater the initial force, the more the force decay [12]. Balhoff et al. evaluated elastomeric chain products from four different companies, and found statistically significant differences in the mean percentage force decay among the tested elastomeric chains. Ormco products had the lowest amount of force decay, while Unitek products had the highest amount force decay [13].

Numerous past studies have evaluated the force decay of elastomeric chains. However, no published research was found that compared the percentage force decay of all the clear and semi-clear elastomeric chains produced by several manufacturers and related this to the discoloration of the orthodontic elastomeric chains after exposure to dietary media. Hence, the aims of this study were twofold: elastomeric chain products from nine different companies were compared to evaluate, firstly, the percentage force decay, and, secondly, the amount of discoloration after immersion in colored dietary media. The null hypothesis for this study is that there would be no significant difference in force decay or color changes of clear orthodontic elastomeric chains.


que les chaıˆnettes heures [6]. Hershey et Reynolds ont trouve
lastome
riques ne conservaient, apre s quatre heures, que e
te
rapporte
40 % de leur force initiale [4]. Par ailleurs, il a e s 21 jours, les modules e
lastome
riques avec les que, apre
leve
es (modules courts) subissaient forces initiales les plus e
gradation de force que les modules moins de de
lastome
riques avec des valeurs de force initiales plus faibles e (modules longs) [11]. Lu et al. ont fait observer que la
gradation de force la plus importante se produisait lorsque de
tait e
leve
e et, e
galement, que plus la force la force initiale e
tait grande, plus grande aussi e
tait la de
gradation de initiale e
value
les chaıˆnettes force [12]. Balhoff et al. ont e
lastome
riques produites par quatre fabricants diffe
rents et e
des diffe
rences statistiquement significatives parmi ont trouve
gradation de force des les pourcentages moyens de de
lastome
riques teste
es. Les produits Ormco affichaıˆnettes e
s de de
gradation de force les plus faibles chaient les quantite
sentait le degre
de de
gradation de force le alors que Unitek pre
leve
[13]. plus e
tudes ont e
value
la de
gradation de force des De nombreuses e
lastome
riques. Cependant, aucune n’a e
te
chaıˆnettes e
e dans la litte
rature qui comparait le pourcentage de trouve
gradation de force de toutes les chaıˆnettes e
lastome
riques de transparentes et semi-transparentes produites par divers fab
ration de la teinte des chaıˆnettes ricants par rapport a` l’alte
lastome
riques apre s exposition a` des suborthodontiques e
quence, l’objectif de cette stances alimentaires. En conse
tude e
tait double : les chaıˆnettes e
lastome
riques produites e
rents ont e
te
compare
es afin par neuf fabricants diffe
valuer, primo, les pourcentages de de
gradation de force d’e
de de
coloration apre s immersion dans et, secundo, le degre
es. L’hypothe se nulle de des substances alimentaires colore
tude e
tait qu’il n’existerait pas de diffe
rence de cette e
gradation de force ou de changements de teinte parmi les de
lastome
riques orthodontiques. chaıˆnettes e

Materials and methods


riel et me
thodes Mate

All the clear and semi-clear (pearl, obscure) orthodontic elastomeric chains (short/closed/continuous) from the following eight manufacturers were investigated: 3M/Unitek (Monrovia, CA, USA), American Orthodontics (Sheboygan, WI, USA), Dentaurum (Ispringen, Germany), Dentsply/GAC (Bohemia, NY, USA), Ormco/Sybron (Orange, CA, USA), Ortho Organizers (Carlsbad, CA, USA), Rocky Mountain Orthodontics (Denver, CO, USA), and TP Orthodontics (La Porte, IN, USA; Table I).


lastome
riques orthodontiques (courtes, Toutes les chaıˆnettes e
es, continues) transparentes et semi-transparentes ferme (perle, obscure) provenant des huit fabricants suivants ont

te
e
tudie
es : 3M/Unitek (Monrovia, CA, Etats-Unis), e American
Orthodontics (Sheboygan, WI, Etats-Unis), Dentaurum
(Ispringen, Allemagne), Dentsply/GAC (Bohemia, NY, Etats
Unis), Ormco/Sybron (Orange, CA, Etats-Unis), Ortho
Organizers (Carlsbad, CA, Etats-Unis), Rocky Mountain
Orthodontics (Denver, CO, Etats-Unis), et TP Orthodontics
(La Porte, IN, Etats-Unis ; Tableau I).

Color stability analysis


chromatique Analyse de la stabilite

A spectrophotometer (ColorEye 7000 A, Model C6, GretageMacbeth, New Windsor, NY, USA) was used to measure the color of each specimen of clear and semi-clear (pearl, obscure) orthodontic elastomeric chains (10 of each type) at

tre (ColorEye 7000 A, Model C6, Un spectrophotome

te
utilise
GretageMacbeth, New Windsor, NY, Etats-Unis) ae
but de l’e
tude pour mesurer la teinte de chaque spe
ciau de
lastome
riques orthodontiques men parmi les chaıˆnettes e

4

International Orthodontics 2015 ; X : 1-15

ORTHO 175 1-15

Color stability and force decay of clear orthodontic elastomeric chains: An in vitro study


chromatique et de
gradation de la force de chaıˆnettes e
lastome
riques orthodontiques transparentes : une e
tude in vitro Stabilite

Table I

Tableau I

Clear and semi-clear elastomeric chains investigated in this study.

Manufacturer/ Fabricant 3M/Unitek American Orthodontics Dentaurum Dentsply Gac

Ormco Ortho Organizers RMO TP Orthodontics

Brand/Type name / Marque/Type Bobbin Chain Clear Ck Alastik Bobbin Chain Obscure Ck Alastik Memory Chain Clear Closed Clear Plastic Chain – Closed Elasto-Force Chain Clear, 150 Closed Super Elasto-Force Transparent (Nc) Super Elastic Chain Short Clear Super Elastic Chain Short Pearl Sili Chain Short Clear Sili Chain Short Pearl Super Chain Clear Short 2 m Clear Generation Ii Pc Closed Space Clear Chain Elastic 150 Cont. Pearl Chain 150 Continuous Energy Chain Closed Clear E-Chain Clear Small 50 Elast-O-Chain 0.02900 Thick 50 E-Chain Tooth-Colored Small 50 Super Slick Chain (Ssc) Small Clear

baseline against a white background using CIE (L*a*b*) relative to a standard illuminate D65. The total number of samples tested was 190 (19 different elastomeric chain types
10 specimens). For each specimen, measurements were undertaken at three areas separately, and then the mean was calculated. To ensure blinding and randomization, specimens were number-coded and randomly selected for the tests. Specimens were then soaked in a dietary media: coffee (NespressoÒ, Nestl
e, Switzerland), tea (LiptonÒ, Unilever, USA) brewed per the manufacturer’s instructions, cola (PepsiÒ, Pepsi Co., USA), and wine (red grape juice) in 250 ml amounts for 72 h. The elastomeric chains were then removed, rinsed, air-dried, and final color readings taken.

The magnitude of total color difference (between baseline and after immersion) is represented by1 a single number DE, where DE = [(DL*)2 + (Da*)2 + (Db*)2] /2. The CIE L*a*b* color space consists of three coordinates L*, a*, b*: L* (lightness), a* green–red (–a* = green; +a* = red), and b* blue–yellow (b* = blue; +b* = yellow).

International Orthodontics 2015 ; X : 1-15


lastome
riques transparentes et semiLes chaıˆnettes e
es dans cette e
tude. transparentes analyse

Code 3M-Clear 3M-Obscure AO-Memory AO-Plastic Dent-Elasto DENT-Super Gac-Elasticc GAC-Elasticp GAC-Siliclear GAC-Silipearl GAC-Super Ormco Orthoo-Clear Ortho-Pearl RMO TP-Clear TP-Elastoch TP-Toothc TP-Superslick

(10 de chaque type) transparentes et semi-transparentes
te
visionne
es sur fond (perle, obscure). Les chaıˆnettes ont e
standard blanc utilisant CIE (L*a*b*) relatif a` une luminosite
chantillons teste
s e
tait de 190 (19 D65. Le nombre total d’e
lastome
riques diffe
rentes
10 spe
citypes de chaıˆnettes e
taient re
alise
es sur chaque spe
cimen mens). Les mesures e
rents et la moyenne a e
te
calcule
e. Pour a` trois endroits diffe re « en aveugle » et la randomisation de garantir le caracte
cimens ont e
te
code
s par chiffres et l’analyse, les spe
lectionne
s de fa¸con randomise
e pour les tests. Les spe
cise
te
immerge
s pendant 72 heures dans 250 mL mens ont e
(NespressoÒ, Nestle
, d’une substance alimentaire : cafe Ò

pare
selon les
(Lipton , Unilever, Etats-Unis) pre Suisse), the
instructions du fabricant, cola (PepsiÒ, Pepsi Co., Etats-Unis) et vin (jus de raisin rouge). Ensuite, les chaıˆnettes
lastome
riques ont e
te
retire
es, rince
es et se
che
es a` l’air e avant lecture de la teinte finale.
rence de couleur totale (entre la valeur L’amplitude de la diffe s l’immersion) est repre
sente
e par un chiffre initiale et apre 1 unique DE, ou` DE = [(DL*)2 + (Da*)2 + (Db*)2] /2.
es L’espace de couleur CIE L*a*b* consiste en trois coordonne
de la couleur), a* vert-rouge L*, a*, b* : L* (intensite (–a* = vert ; +a* = rouge), et b* bleu-jaune (b* = bleu ; +b* = jaune).

5

ORTHO 175 1-15

Abdullah M. ALDREES et al.

The effects on chromaticity and lightness coordinates (DL*, Da*, and Db*) as a result of exposure to diet substances were determined and the changes in color (DE) assessed by the relationship: DL* = L*f  L*i, Da* = a*f  a*i, Db* = b*fb*i, where the subscripts “f” and “i” represent the final and initial values corresponding to ‘after’ and ‘before’ environmental exposures, respectively. The computed value of DE is traditionally used to assess color changes. Differences of one or two units in DE may indicate some distinguishable stain. A detailed study by Ruyter et al. has shown that a shift in DE value of >3.3 reflects a change that is a clinically significant visual discoloration [14].


es de la chromaticite
et de L’impact sur les coordonne
de la couleur (DL*, Da*, et Db*) suivant l’exposition l’intensite
te
de
termine
et les alte
rations aux substances alimentaires a e
te
calcule
es utilisant la relation : DL* = L*f de teinte (DE) ont e
rieurs « f »  L*i, Da* = a*f  a*i, Db* = b*fb*i ou` les indices infe
sentent les valeurs finale et initiale corresponet « i » repre dant, respectivement, aux expositions environnementales s » et « avant ». La valeur calcule
e de DE est utilise
e, « apre
valuer les modifications de couleur. traditionnellement, pour e
rences d’une ou de deux unite
s de DE peuvent indiLes diffe
tude de
taille
e de Ruyter quer une tache perceptible. Une e
montre
qu’une modification de la valeur de DE et al. a de te une de
coloration visuelle cliniquement de > 3,3 refle significative [14].

Force decay measurements


gradation de force Prise de mesures de la de

Three rectangular metal jigs provided the basis for activating the elastomeric chains. Each jig has two sides that host 19 pairs of stainless steel pins symmetrically aligned in rows and separated by a distance that represents double the original length of each E-chain specimen. Six samples from each of the 19 types of elastomeric chains were selected and cut to the appropriate length. During the study, the jigs along with the elastomeric chains were submerged in a solution of artificial saliva and preserved at 37  C in an incubator imitating oral conditions.


tallique ont permis d’activer les Trois dispositifs de fixation me
lastome
riques. Chaque dispositif disposait de chaıˆnettes e deux faces recevant 19 paires de crochets en acier inoxydable
es syme
triquement et situe
es a` une distance de deux aligne
cimen de chaıˆnette. Six fois la longueur initiale de chaque spe
chantillons de chacun des 19 types de chaıˆnette e
lastome
rique ont e
te
se
lectionne
s et sectionne
s a` une longe
e. Pendant l’e
tude, les dispositifs de fixation et ueur approprie
lastome
riques ont e
te
immerge
s dans une les chaıˆnettes e
s a` 37  C dans une solution de salive artificielle et conserve
orale. couveuse afin de reproduire les conditions de la cavite
gradation de force a e
te
mesure
e en utilisant une jauge La de
lectronique (Shimpo DFS-1 ; Nidec-Shimpo America de force e

e a` un banc d’essai e
quipe
Corp., Itasca, Etats-Unis), attache
lastome
riques ont d’une plateforme flexible. Les chaıˆnettes e
te
attache
es a` la jauge de force e
lectronique et stabilise
es e pendant 5 secondes avant l’enregistrement des niveaux de
es ont e
te
reporte
es sur un tableur force. Les forces mesure
s ExcelÒ (Microsoft Corp., Redmond, WA, Etats-Unis). Apre
te
place
es sur chaque prise de mesure, les chaıˆnettes ont e
es dans la couleurs dispositifs de fixation respectifs et replace
riode de 28 jours, la force initiale (en veuse. Sur une pe
de de
gradation de force (en pourcengrammes) et la quantite
te
mesure
es et compare
es aux valeurs initiales tages) ont e
lectronique. pour chaque chaıˆnette utilisant la jauge de force e
te
e
value
s a` cinq intervalles Les niveaux de force ont e
de
termine
s : initial, une semaine, deux semaines, trois pre
te
re
alise
es semaines et quatre semaines. Les mesures ont e
te
calcule
e. quatre fois et la moyenne a e

The force decay was measured using an electronic force gauge (Shimpo DFS-1; Nidec-Shimpo America Corp., Itasca, USA), which was attached to a test stand with a flexible platform. The E-chains were attached to the electronic force gauge then stabilized for 5 s before recording the force levels. The measured forces were then recorded in an ExcelÒ (Microsoft Corp., Redmond, WA, USA) spreadsheet. After each measurement, the elastomeric chains were placed onto their respective jigs, and subsequently back into the incubator. Over a period of 28 days, the initial force (in grams) and the amount of force decay (in percentages) were measured, compared with the baseline values for each E-chain using the electronic force gauge. Force levels were evaluated at five predetermined time intervals: initial, one week, two weeks, three weeks, and four weeks. Measurements were taken four times and the mean was calculated.

Statistical analysis

Analyse statistique

The changes in color and force decay were analyzed using a one-way analysis of variance. Tukey-Kramer (HSD) multiple comparison was performed as a post hoc test using PASWÒ Statistics 18 (SPSS Inc., Chicago, United States). Significance level was set at P = 0.05.


gradation de force ont e
te
Les changements de teinte et de de
s utilisant une analyse de variance a` un facteur. Une analyse
te
re
alise
e en comparaison multiple Tukey-Kramer (HSD) a e tant que test post hoc utilisant PASWÒ Statistics 18 (SPSS

ae
te
Inc., Chicago, Etats-Unis). Le niveau de significativite
a` p = 0,05. fixe

6

International Orthodontics 2015 ; X : 1-15

ORTHO 175 1-15

Color stability and force decay of clear orthodontic elastomeric chains: An in vitro study


chromatique et de
gradation de la force de chaıˆnettes e
lastome
riques orthodontiques transparentes : une e
tude in vitro Stabilite

Results


sultats Re

Means, standard deviations, and percentages of the lost initial force of the 19 tested types of elastomeric chains before activation and at the end of each week during the observation period are listed in Table II. For all of the tested E-chains, a significant difference was shown in the percentage of the lost initial force between the four weeks tested with ANOVA (P < 0.001), except for OrthoO-Clear and TP-Clear which did not show a significant difference between the forces at the third and the fourth weeks (P = 0.569, and P = 0.816, respectively). A comparison between the percentage values of the remaining forces of the studied E-chains at the end of the fourth week is represented in fig. 1. AO-Memory and ORMCO E-chains preserved most of the initial forces, while TP-ToothC, TPElastoCh, and OrthoO-Clear retained the least amount of the initial forces. When the initial force values were compared with the percentages of the remaining forces at the end of fourth week using Pearson correlation, a statistically significant moderate negative correlation (r = 0.503, P < 0.001) resulted. This means that there is a tendency toward retaining most of the initial force when the initial force is low.


carts-types et pourcentages de la perte de force Moyennes, e
lastome
riques teste
s initiale des 19 types de chaıˆnettes e avant l’activation et a` la fin de chaque semaine pendant la
riode d’observation sont donne
s dans le Tableau II. pe
es, une diffe
rence significative Pour toutes les chaıˆnettes teste
te
observe
e entre les quatre de perte de force initiale a e
es avec ANOVA (< 0,001), a` l’exception semaines teste
de diffe
rd’OrthoO-Clear et de TP-Clear qui n’ont pas montre me et quatrie me ence significative entre les forces aux troisie semaines (p = 0,569 et p = 0,816, respectivement). Une comparaison entre les pourcentages des forces
siduelles des chaıˆnettes e
tudie
es a` la fin de la quatrie me re
sente
e sur la fig. 1. Les chaıˆnettes AOsemaine est pre
les forces initiales, Memory et ORMCO ont le mieux conserve alors que TP-ToothC, TP-ElastoCh et OrthoO-Clear en ont
les quantite
s les moins importantes. Une compaconserve
lation de Pearson des valeurs des raison utilisant la corre
siduelles forces initiales et des pourcentages des forces re me semaine montre une corre
lation en fin de la quatrie
gative statistiquement significative (r = 0,503 ; p < 0,001). ne
sultat signifie qu’il existe une tendance des chaıˆnettes Ce re a` conserver la plupart de la force initiale quand la force initiale est faible.
sume les tests Tukey (HSD) post hoc Le Tableau III re
siduelles en fin de comparant les pourcentages des forces re me semaine des 19 types de chaıˆnettes teste
s. Les la quatrie
es dans le tableau selon la quantite
de chaıˆnettes sont classe
siduelle, qui s’e
tale de 61,3 a` 25,4 % (Tableau III). Des force re
rences significatives ont e
te
observe
es entre les types de diffe

Table III shows the summary of the Tukey (HSD) post hoc tests comparing the percentages of the remaining forces at the end of the fourth week of the 19 tested E-chain types. E-chains were ranked in the table based on the amount of the remaining force, which ranged from 61.3 to 25.4% (Table III). Significant

[(Fig._1)TD$IG]

Fig. 1: The mean percentage of force decay and the amount of color change (DE) of the studied elastomeric chains at the end of the study period.
gradation de la force et la quantite
d’alte
ration Fig. 1 : Le pourcentage moyen de de
lastome
riques e
tudie
es a` la fin de la pe
riode d’e
tude. chromatique (DE) des chaıˆnes e

International Orthodontics 2015 ; X : 1-15

7

Brand/Type /


carts-types de la force initiale (grammes) et de la force en fin de chaque Moyennes et e
lastome
riques semaine ainsi que le pourcentage (%) de force perdue pour les chaıˆnettes e
tudie
es. e

Baseline / Initial

First week / 1ersemaine

Second week / 2esemaine

Third week / 3esemaine

Fourth week / 4esemaine

Mean /

SD /

Mean /

SD / % Loss / Mean /

SD /

% Loss / Mean /

SD / % Loss / Mean /

SD / % Loss /

Moyenne

E-T

Moyenne

E-T

% Perte

Moyenne

E-T

% Perte

Moyenne

E-T

% Perte

Moyenne

E-T

Marque/Type % Perte

International Orthodontics 2015 ; X : 1-15

3M-Clear

342.13

7.2

240.67

15.5

31.74

202.83

10.2

44.76

170.46

19.1

50.18

152.88

7.7

55.32

3M-Obscure

287.08

8

212.29

7.7

26.05

177.75

14.9

38.1

154.75

23.6

46.1

142.96

9.7

50.2

AO-Memory

286.83

15.9

228.88

23.5

20.2

201.88

7.5

29.62

184.29

9.5

35.75

175.83

13.1

38.7

AO-Plastic

452.79

9.9

219.04

16.7

51.62

193.21

17.4

57.33

176.63

9.6

60.99

162.79

6.2

64.05

DENT-Elasto

484.08

8.5

223.38

7.9

53.86

202.83

8

58.1

186.46

9

61.48

172.58

11.3

64.35

DENT-Super

431.92

12.1

231.71

12.3

46.35

196.75

12.3

54.45

175

10.2

59.48

164.67

9.7

61.88

GAC-ElasticC

414.71

13.6

238.88

19

42.4

212.63

17.6

48.73

188.83

13.8

54.47

181.58

13.5

56.21

GAC-ElasticP

350.5

20.3

221.54

17.3

36.79

192.42

12.5

45.1

172.83

12

50.69

165.88

18.4

52.68

GAC-SiliClear

354.38

17.7

248.25

17.6

29.94

206.96

19.3

41.6

176.29

17.3

50.26

171.58

21.5

51.58

GAC-SiliPearl

442.58

9

241.33

16

45.47

209.29

52.71

184.83

12.7

58.24

178.17

13.2

59.74

GAC-Super

333.21

11

240.67

15.5

27.77

202.83

10.2

39.13

174.17

19.4

47.73

164.13

13.7

50.74

ORMCO

282.25

10.1

243.17

8.2

13.85

211.63

10

25.02

182.42

3.4

35.37

166.17

13.2

41.13

132.92

10.7

74.58*

144.04

12.6

65.84

167.29

12

50.29

313.04

12.6

53.55**

8.14

OrthoO-Clear

522.96

7.5

219.5

19.7

58.03

189.5

22.2

63.76

134.38

18.9

74.30

OrthO-Pearl

421.63

8.6

233.79

11.8

44.55

211.63

11.3

49.81

154.33

13.2

63.4

RMO

336.54

1.0.1

235.92

11.8

29.9

190.67

14.7

43.35

177.38

15.7

47.3

*

**

TP-Clear

673.92

8

432.17

15.2

35.87

380.21

13.1

43.58

312.25

13.5

53.67

TP-ElastoCh

421.33

12

189.25

15.1

55.08

143.67

16.6

65.9

122.54

18

70.92

111.58

11.3

73.52

TP-ToothC

422.13

212.29

6.8

49.71

179.83

14.3

57.4

132.63

10.6

68.58

122.25

11.2

71.04

9.3

* P = 0.569, ** P = 0.816: non-significant difference.

Abdullah M. ALDREES et al.

Tableau II

Mean and SD of the initial force (grams) and of the force at the end of each week, and the percentage (%) of the lost force for studied elastomeric chains.

ORTHO 175 1-15

8

Table II

ORTHO 175 1-15

Color stability and force decay of clear orthodontic elastomeric chains: An in vitro study


chromatique et de
gradation de la force de chaıˆnettes e
lastome
riques orthodontiques transparentes : une e
tude in vitro Stabilite

When the changes in three CIE L*a*b* color space coordinates (DL*, Da*, Db*) were compared using ANOVA, significant differences between the means of the three coordinates (Da* = 9.69104, DL* = 15.25608, Db* = 26.80866) were seen (P < 0.001). The coordinate (b*), which measures the chromaticity in the blue–yellow hue range (–b* = blue;

chaıˆnettes (p < 0,001), a` l’exception des trois groupes mon
s dans le tableau. tre
carts-types de la quantite
de changeLes moyennes et les e
tudie
es apre s ment chromatique (DE) des chaıˆnettes e
s dans le Tableau IV. L’ANOVA montre l’immersion sont donne
rence significative de degre
de de
coloration entre les une diffe
sultats du test post hoc types de chaıˆnettes (p < 0,001). Les re regroupent les types de chaıˆnettes en 7 groupes distincts qui
rences significatives entre les diffe
rents montrent des diffe
s dans le tableau types. Les types de chaıˆnettes sont classe
de changement de teinte (DE), repre
sente
selon le degre graphiquement sur la fig. 1. Les types de chaıˆnettes semitransparentes (couleur dent/perle/obscure – TP-ToothC,
sentent, de OrthO-Pearl, GAC-SiliPearl, 3M-Obscure) pre
rente et significative, moins de changement fa¸con cohe ^mes marde teinte que les chaıˆnettes transparentes des me ques (TP-Clear, OrthoO-Clear, GAC-SiliClear, 3M-Clear).
volutions des En comparant, a` l’aide d’ANOVA, les e
es de l’espace colorime
trique CIE L*a*b* trois coordonne
rences significatives (DL*, Da*, Db*), on observe des diffe
es (Da* = 9,69104 ; entre les moyennes des trois coordonne DL* = 15,25608 ; Db* = 26,80866 ; p < 0,001). La

Table III

Tableau III

differences between the E-chain types were observed (P < 0.001) except for the three groups shown in the table. Means and standard deviations of the amount of color change (DE) of the studied E-chains after the immersion are listed in Table IV. ANOVA shows a significant difference in the amount of discoloration between the E-chain types (P < 0.001). Post hoc test results combined the E-chain types into seven distinct groups that show significant differences from each other. Echain types are ranked in the table based on their amount of color change (DE), which is represented graphically in fig. 1. Semi-clear (tooth-color/pearl/obscure) E-chain types (TPToothC, OrthO-Pearl, GAC-SiliPearl, 3M-Obscure) present consistently and significantly less change in color than clear E-chains of the same brand (TP-Clear, OrthoO-Clear, GACSiliClear, 3M-Clear).

Mean and SD of the remaining force (%) of the studied elastomeric chains at the end of the four-week evaluation period, and a summary of the Tukey (HSD) post hoc multiple comparison tests.

Brand/Type / Marque/Type

AO-Memory ORMCO 3M-Obscure RMO GAC-Super GAC-SiliClear GAC-ElasticP TP-Clear 3M-Clear GAC-ElasticC TP-SuperSlick GAC-SiliPearl DENT-Super AO-Plastic DENT-Elasto OrthO-Pearl TP-ToothC TP-ElastoCh

Remaining force (%) /
Force residuelle (%)

61.3 58.87 49.8 49.71 49.26 48.42 47.32 46.45 44.68 43.79 43.49 40.26 38.13 35.95 35.65 34.16 28.96 26.48

International Orthodontics 2015 ; X : 1-15


carts-types de la force re
siduelle (%) des Moyennes et e
lastome
riques e
tudie
es en fin de la pe
riode chaıˆnettes e
valuation de 4 semaines, et un re
sume
des tests Tukey d’e (HSD) post hoc de comparaison multiple.

Tukey (HSD) post hoc test / Test Tukey (HSD) post hoc
Non-significant differences / Differences non significatives

RMO, P = 1.000 3M-Obscure, P = 1.000 3M-Obscure, P = 0.551

GAC-Super, P = 0.551 GAC-Super, P = 0.828 RMO, P = 0.828

TP-SuperSlick, P = 0.997 GAC-ElasticC, P = 0.997

DENT-Elasto, P = 0.996 AO-Plastic, P = 0.996

9

Brand/Type /

Color change (DE) /

Marque/Type

Changement chromatique (DE)

Mean /

SD / E-T

Moyenne

TPToothC

OrthOPearl

TPSuperSlick

TPClear


carts-types de l’alte
ration chromatique des chaıˆnettes e
lastome
riques Moyennes et e
tudie
es apre s immersion pendant 72 h, et un re
sume
des tests Tukey (HSD) post hoc de e comparaison multiple.

TPElastoCh

OrthoOClear

GACElasticP

AOMemory

0.998

0.955

0.217

ORMCO

GACSuper

GACSiliPearl

RMO

3MObscure

GACSiliClear

AOPlastic

GACElasticC

DENTElasto

DENTSuper

3MClear

95% confidence interval for mean / 95 % intervalle de confiance des moyennes

Lower /

Upper /


Inferieur


Superieur

International Orthodontics 2015 ; X : 1-15

TP-ToothC

19.94

1.2

19.07

20.8

OrthO-Pearl

23.48

0.9

22.84

24.12

TP-SuperSlick

24.21

1.82

22.91

25.51

1

TP-Clear

25.36

1.58

24.23

26.49

0.268

TP-ElastoCh

29.84

1.84

28.53

31.15

OrthoO-Clear

30.69

1.61

29.54

31.84

0.998

GAC-ElasticP

30.99

1.29

30.07

31.91

0.955

1

AO-Memory

31.78

1.07

31.02

32.55

0.217

0.972

0.999

ORMCO

32.58

1.19

31.73

33.43

0.26

0.575

GAC-Super

33.8

0.95

33.12

34.48

GAC-SiliPearl

34.14

0.95

33.46

34.82

RMO

35.33

1.22

34.46

36.2

0.645

0.936

3M-Obscure

35.94

0.81

35.36

36.52

0.099

0.342

1

GAC-SiliClear

36.38

1.97

34.98

37.79

0.065

0.981

1

AO-Plastic

37.44

1.99

36.02

38.87

0.114

0.682

GAC-ElasticC

40.67

1.36

39.7

41.64

DENT-Elasto

40.71

1.74

39.46

41.95

1

DENT-Super

42.65

1.43

41.63

43.68

0.188

1

0.268 0.954

0.954

1

0.972

0.26

0.999

0.575 0.999

0.999 0.169

0.169 0.926

0.926 0.621

0.621 1

1

0.645

0.099

0.936

0.342

0.065

1

0.981 1

0.114 0.682 0.978

0.978 1

0.188 0.215

0.215

1

Abdullah M. ALDREES et al.

Tableau IV

Mean and SD of color change (DE) of the studied elastomeric chains after immersion for 72 h, and a summary of the Tukey (HSD) post hoc multiple comparison tests.

ORTHO 175 1-15

10

Table IV

ORTHO 175 1-15

Color stability and force decay of clear orthodontic elastomeric chains: An in vitro study


chromatique et de
gradation de la force de chaıˆnettes e
lastome
riques orthodontiques transparentes : une e
tude in vitro Stabilite

+b* = yellow) presented the most significant amount of change in the yellowness direction.


e (b*), qui mesure la chromaticite
dans la gamme coordonne
sentait la des teintes bleu-jaune (–b* = bleu ; +b* = jaune), pre
de changement la plus significative en direction du quantite jaune.

Discussion

Discussion

The esthetic value of the clinical use of clear orthodontic fixed appliances is affected by the shade of the elastomeric chains that are commonly used for space closure. All the commercially available clear and semi-clear elastomeric chins are marketed for utilization along with ceramic orthodontic brackets. However, their discoloration is a source of concern for patients and clinicians. All the tested E-chains showed a significant amount of staining after exposure to dietary media. This observation not only confirms the clinical perception of the orthodontists, but further provides data regarding the measurable change that aids clinicians in their selection of Echains. The present study also showed that different types of clear and semi-clear E-chains change their color to different degrees. However, all the studied E-chains presented a change (DE) ranging from 19.9 to 43.4. All these values are significantly above the perceptible degree reported by Ruyter et al. (>3.3), and even beyond the threshold value reported by Douglas et al. (>5.5) [14,15].


tique de l’utilisation des appareils orthodonLa valeur esthe
e par la teinte des tiques fixes transparents est influence
lastome
riques couramment utilise
es pour la ferchaıˆnettes e
lastome
riques meture des espaces. Toutes les chaıˆnettes e transparentes et semi-transparentes disponibles sur le
sont commercialise
es pour e ^ tre utilise
es avec des marche
ramique. Cependant, la brackets orthodontiques en ce
coloration qu’elles subissent est une pre
occupation pour de ^me que pour les cliniciens. Toutes les les patients, de me
es ont pre
sente
une quantite
significative chaıˆnettes teste
ration de teinte apre s immersion dans des substances d’alte alimentaires. Cette observation confirme non seulement le
cu clinique des orthodontistes, mais fournit des preuves ve
mentaires concernant ces changements quantifiables supple
lectionner leurs chaıˆnettes. qui peuvent aider les cliniciens a` se
sente e
tude a e
galement de
montre
que la couleur des La pre divers types de chaıˆnettes transparentes et semi-transpar
volue a` des degre
s diffe
rents. Cependant, toutes les entes e
tudie
es ont manifeste
une modification de teinte chaıˆnettes e (DE) comprise entre 19,9 et 43,4. Toutes ces valeurs sont
rieures au degre
perceptible rapporte
significativement supe
passe me ^me la valeur seuil par Ruyter et al. (> 3,3), et de
e par Douglas et al. (> 5,5) [14,15]. rapporte
te
de
montre
que la spectrophotome
trie est capable de Il a e
riaux dentaires mesurer avec exactitude la couleur des mate
sente e
tude est la premie re a` utiliser la spectro[16]. La pre
trie pour e
valuer les changements chromatiques des photome
ce
dentes tentatives pour quantifier la chaıˆnettes. Les pre
coloration des modules e
lastome
riques orthodontiques de
chelle analogue visuelle base
e sur une ont fait appel a` une e
valuation visuelle humaine [6] ou sur les images nume
riques e
alise
es avec un appareil photographique des modules re
es a` l’aide d’un logiciel [8], ou de la colorime
trie et traite
sultats ont tristimulus (Minolta Chromameter) [7]. Nos re
que les chaıˆnettes semi-transparentes (TP-ToothC, montre OrthO-Pearl, GAC-SiliPearl, 3M-Obscure) ont tendance
senter significativement moins de de
coloration que a` pre
quivalents transparents (TP-Clear, OrthoO-Clear, leurs e
sultats GAC-SiliClear, 3M-Clear). Ainsi, ils confirment les re
de d’Ardeshna et Vaidyanathan qui ont conclu que le degre
coloration varie selon la teinte originelle du module. Ils monde trent aussi que les modules transparents ou de couleur plus
sentaient plus de changement que les couleurs plus claire pre
es [7]. fonce Du point de vue clinique, beaucoup de facteurs peuvent influer
lastome
riques sur le changement de teinte des chaıˆnettes e
tudes in vitro. Des qu’il est impossible de simuler dans des e
rences individuelles de consommation de certaines diffe

It has been shown that spectrophotometric measurements are capable of accurately measuring the color of dental materials [16]. This is the first study that utilized spectrophotometry to measure the color change of elastomeric chains. Previous attempts to quantify discoloration of orthodontic elastomeric modules used a visual analogue scale which relies on human visual evaluation [6], or digital images of the modules which were taken with a camera and processed with software [8], or tristimulus colorimetry (Minolta Chromameter) [7]. Our results showed that semi-clear E-chains (TP-ToothC, OrthOPearl, GAC-SiliPearl, 3M-Obscure) tend to present significantly less discoloration than their equivalent clear chains (TP-Clear, OrthoO-Clear, GAC-SiliClear, 3M-Clear). This confirms the findings of Ardeshna and Vaidyanathan who concluded that the degree of discoloration varies with the original color of the module. They stated that clear and lighter colored modules exhibited more change than darker colors [7].

Clinically, many factors can influence the change in color of elastomeric chains that cannot be simulated in in vitro studies. Individual differences in the consumption of certain colored dietary media like spices and the variable concentrations of

International Orthodontics 2015 ; X : 1-15

11

ORTHO 175 1-15

Abdullah M. ALDREES et al.

the other consumed beverages can influence the degree of discoloration of E-chains. The effect of saliva in reducing the concentration of the dietary media around the brackets and preventing the build-up of stains is another factor that can only be studied in vivo. Dimensional and surface changes of the E-chains that result from stretching them around the brackets can also influence their reaction to dietary media.

Similar to previous studies [11,17–19], the tested E-chains applied a significantly wide range of initial forces (282.25– 673.92 g) that were higher than the amount of tooth retraction force (100–250 g) recommended by Storey and Smith and Reitan [20,21]. The moderately significant negative relationship between the initial forces and the remaining force observed in the current study agrees with the studies of Lu et al. and Oshagh and Ajami [12,17]. Others concluded that there is no association between the initial forces and the amount of force decay [4,13,22]. Differences in study design between these reports could explain the contrasting conclusions. In the present study, the average remaining force of the elastomeric chains after three weeks of activation was 45.1%. This figure matches the findings of Grassi et al. (20–40%), Hershey and Reynolds (41%), and De Genova et al. (39.1–56%) [4,11,23]. However, Oshagh and Ajami reported a significantly lower percentage of remaining force (15.84%) at the end of the third week of activation [17]. The use by the investigators of a dial type dynamometer for the force measurements may explain the wide range of forces and the large standard deviations reported by Oshagh and Ajami, and thus may have affected the accuracy of their measurements. After four weeks of activation, an average 42.5% of the initial force was maintained in our study. Rock et al. have reported that 50% of the initial forces were maintained after one month, and Hershey and Reynolds reported that 41% of the initial force remained after four weeks [4,24]. Masoud et al. have recently reported that thermoset E-chains showed less force decay in comparison with thermoplastic E-chains and required more stretching to reach the desired forces. The difference in force decay between the two groups was approximately 20% [25].

Clinical behavior of elastomeric chains may differ from their performance in in vitro studies. For example, Larrabee et al. have shown that the alcohol in mouth rinses increased the amount of force decay [26]. Thus, comprehensive clinical evaluation of the tested E-chains would provide more data about the effect – if any – of force degradation on the rate of tooth retraction. Unfortunately, the types of E-chains that performed well in maintaining their initial force at the end of the observation period did not behave similarly in resisting discoloration. These results make the selection of the optimum

12


es telles que les e
pices et les substances alimentaires colore
es concentrations variables des autres boissons consomme
de de
coloration des peuvent avoir un effet sur le degre
duction de la concenchaıˆnettes. L’impact de la salive sur la re tration des substances alimentaires autour des brackets ainsi
po ^ts constitue un autre facteur qui que sur la diminution des de ^tre e
tudie
qu’in vivo. Les changements de dimenne peut e
sultent lorsqu’elles sions et de superficie des chaıˆnettes qui re
tire
es autour des brackets peuvent e
galement avoir une sont e
action aux aliments. incidence sur leur re
tudes ante
rieures [11,17–19], les Comme dans des e
es ont exerce
une gamme significativement chaıˆnettes teste
taient plus large de forces initiales (282,25–673,92 g), qui e
leve
es que la quantite
de force de re
traction dentaire (100– e
conise
e par Storey et Smith, et Reitan [20,21]. La 250 g), pre
gative mode
re
ment significative entre les forces relation ne
siduelles observe
e dans la pre
sente initiales et les forces re
tude concordent avec les re
sultats de Lu et al. et de Oshagh e et Ajami [12,17]. D’autres auteurs ont conclu a` l’absence
de d’association entre les forces initiales et la quantite
gradation de force [4,13,22]. Les diffe
rences de protocole de
tudes pourraient expliquer ces conclusions entre ces e disparates.
sente e
tude, la force re
siduelle moyenne des Dans la pre
lastome
riques apre s 3 semaines d’activation e
tait chaıˆnettes e
sultats de Grassi et al. de 45,1 %. Ce chiffre correspond aux re (20–40 %), de Hershey et Reynolds (41 %), et de De Genova et al. (39,1–56 %) [4,11,23]. Cependant, Oshagh et Ajami ont
un pourcentage significativement moins e
leve
de rapporte
siduelle (15,84 %) a` la fin de la troisie me semaine force re d’activation [17]. L’utilisation par ces chercheurs d’un dynatre a` cadran pour les calculs des forces explique, peutmome ^tre, la large fourchette de forces et les e
carts-types impore
s par ces auteurs et qui ont pu, ainsi, fausser tants rapporte s quatre semaines d’activation, une moyleurs mesures. Apre
tait conserve
e dans notre enne de 42,5 % de la force initiale e
tude. Rock et al. ont rapporte
que 50 % des forces initiales e
taient maintenues apre s un mois, et Hershey et Reynolds e
que 41 % de la force initiale e
tait conserve
ont rapporte s quatre semaines [4,24]. Masoud et al. ont re
cemment apre
que les chaıˆnettes thermoforme
es subissaient observe
gradation de force par rapport aux chaıˆnettes moins de de
lastome
riques thermoplastiques et avaient besoin d’e ^tre e
tire
es avant d’atteindre les forces de
sire
es. La davantage e
rence de de
gradation de force entre les deux groupes diffe
tait de 20 % environ [25]. e
lastome
riques Le comportement clinique des chaıˆnettes e
rer par rapport a` leur comportement dans les e
tudes peut diffe
que l’alcool in vitro. Larrabee et al., par exemple, ont montre
de contenu dans les rince-bouches augmentait la quantite
gradation de force [26]. Ainsi, une e
valuation clinique de
lastome
riques teste
es pourraient exhaustive des chaıˆnettes e
es supple
mentaires concernant l’effet fournir des donne
ventuel de la de
gradation de force sur la vitesse de re
traction e dentaire. Malheureusement, les types de chaıˆnettes qui ont
leur force initiale en fin d’observation avaient bien conserve

International Orthodontics 2015 ; X : 1-15

ORTHO 175 1-15

Color stability and force decay of clear orthodontic elastomeric chains: An in vitro study


chromatique et de
gradation de la force de chaıˆnettes e
lastome
riques orthodontiques transparentes : une e
tude in vitro Stabilite

type of clear E-chain combining esthetic properties and physical performance difficult for the clinician. However, a careful review of the rankings of the tested E-chains in the two lists should provide the orthodontists with clinically relevant data that can aid their decision-making process.


sultats moins probants en ce qui concerne la re
sistance des re
coloration. Pour le clinicien, ces re
sultats signifient que a` la de le choix d’une chaıˆnette transparente optimale combinant car
ristiques esthe
tiques et proprie
te
s physiques reste une acte
cision difficile. Cependant, un examen minutieux des clasde
es dans les deux listes devrait sements des chaıˆnettes teste
es orthodontiques pertifournir aux orthodontistes des donne
cision. nentes et les aider dans leur prise de de

Conclusions

Conclusions

Significant differences in the mean percentage force decay between the 19 studied clear elastomeric chain types were present. The large variation in the initial force and the remaining force levels between the studied clear E-chains suggest different clinical effects of their use. AO-Memory and Ormco maintained most of their original force at the end of the fourweek interval, while TP-ToothC, TP-ElastoCh, and OrthoOClear lost most of their initial force levels.


rences significatives ont e
te
observe
es entre les Des diffe
gradation de force moyenne parmi les pourcentages de de
lastome
riques transparentes. Les 19 types de chaıˆnettes e variations importantes entre les niveaux de force initiale et
siduelle parmi les chaıˆnettes transparentes de force re
tudie
es sugge  rent des effets cliniques diffe
rents lors de leur e
utilisation. Les chaıˆnettes AO-Memory et Ormco ont conserve
riode de 4 la plupart de leur force initiale a` la fin de la pe semaines, alors que les produits TP-ToothC, TP-ElastoCh et OrthoO-Clear ont perdu la plupart de leur force initiale.
rences significatives de de
coloration ont e
te
releve
es Des diffe
rents types de chaıˆnettes. L’alte
ration de teinte entre les diffe
te
la plus affecte
e par Db* et e
tait la plus (vers le jaune) a e significative pour les chaıˆnettes Dentaurum (Elasto, Super), GAC-ElasticC, et 3M-Clear. Les produits TP Orthodontics (couleur dent, SuperSlick, Transparente) et Ortho Organizers
coloration. Les cliniciens (perle) montraient le moins de de peuvent choisir les chaıˆnettes transparentes qui subissent
ration de la teinte. Cependant, les autres le moins d’alte
te
s physiques telles que le pourcentage de de
gradation proprie
galement e ^tre prises en compte. de la force doivent e

Significant differences in discoloration existed between the different types of E-chains. Color change (yellowness) was most affected by Db* and was most significant in Dentaurum products (Elasto, Super), GAC-ElasticC, and 3M-Clear chains. TP Orthodontics (Tooth-Colored, SuperSlick, Clear) and Ortho Organizers (Pearl) showed the least discoloration. Clinicians can select the clear E-chain types that display the minimum amount of color change. However, the other physical properties such as the percentage of force decay should also be considered.

Disclosure of interest


claration d’inte
re ^ts De

The authors declare that they have no conflicts of interest concerning this article.


clarent ne pas avoir de conflits d’inte
re ^ ts en Les auteurs de relation avec cet article.

International Orthodontics 2015 ; X : 1-15

13

ORTHO 175 1-15

Abdullah M. ALDREES et al.

References/Re
fe
rences 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24.

14

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