京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第21886号 / エネ博第387号 / 新制||エネ||75(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻 / (主査)教授 森井 孝, 教授 木下 正弘, 教授 片平 正人 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DGAM

Introduction Cette recherche constitue une étude clinique descriptive, visant à évaluer la douleur durant le traitement orthodontique avec boîtiers auto-ligaturants passifs et actifs. Matériel et méthode L'étude a été effectuée chez 39 patients (18 garçons, 21 filles), âge moyen 14 (entre 11 et 19 ans). Deux types de boîtiers auto-ligaturants ont été utilisés (SPEED n=20 et Damon n=19). Pour évaluer la douleur, un questionnaire a été élaboré par l'équipe de recherche. L’étude comportait 4 phases, c’est-à-dire l’évaluation de la douleur suite à l’insertion des 4 premiers fils orthodontiques du traitement de chaque patient (0.016 Supercable, 016 CuNiTi, 016X022 CuNiTi, 019X025 CuNiTi). Le même questionnaire était utilisé lors de chaque phase et le questionnaire comprenait 6 différents temps (T0: avant l’insertion du fil orthodontique, T1: immédiatement suite à l’insertion du fil, T2: 5h après l’insertion, T3: 24h après l’insertion, T4: 3 jours après l’insertion, T5: une semaine après l’insertion, T6: 4 semaines après l’insertion) suite à l’insertion de chaque fil. L’échelle visuelle analogue (EVA) et la version courte du questionnaire de Saint-Antoine ont été utilisés afin d’évaluer la douleur. Les données des EVA entre les groupes ont été comparées en utilisant le U test Mann-Whitney. Résultats et discussion Pour les deux premiers fils et pour tous les temps étudiés, il n’y avait pas de différence statistiquement significative entre les deux groupes (SPEED et Damon). Cependant, au moment de l’insertion (T0) du troisième fil (016X022 CuNiTi), parmi les patients ayant rapporté de la douleur (SPEED 47.1%, Damon 55.6%), le groupe Damon a rapporté une douleur significativement plus élevée que le groupe SPEED (p=0.018), (EVA moyenne SPEED=14.14±8.55, Damon=33.85±19.64). Trois jours après l’insertion du troisième fil, toujours parmi les patients ayant rapporté de la douleur (SPEED 23.5%, Damon 33.4%), la douleur était significativement plus élevée chez le groupe Damon que chez le groupe SPEED (p=0.008), (EVA moyenne SPEED=8.74±4.87, Damon=25.15±9.69). La plupart des analgésiques ont été pris suite à la pose du premier fil au temps T2 (5h) et T3 (24h). Il n’y avait pas de différence statistiquement significative entre les groupes en ce qui a trait au nombre de patients qui prenaient des analgésiques. La douleur n’a pas affecté le style de vie pour la grande majorité des patients. Les mots descriptifs sensoriels « tiraillement », « étau » et « élancement » et le mot affectif « énervant » étaient le plus souvent utilisés. Conclusion Les patients du groupe Damon ont ressenti significativement plus de douleur que les patients du groupe SPEED à l’insertion du troisième fil et trois jours suite à l’insertion. Plus de patients ont pris des médicaments pour la douleur avec le premier fil et le style de vie n’était pas affecté pour une majorité de patients. « Tiraillement », « étau », « élancement » et « énervant » étaient les mots descriptifs les plus utilisés par les patients pour décrire leur douleur. / Introduction This research is a descriptive clinical study designed to assess pain during orthodontic treatment with self-ligating brackets. Materials and methods This study was comprised of 39 patients (18 male, 21 female), mean age of 14 (range 11 to 19 yo). Two types of self-ligating brackets (SPEED n=20 and Damon n=19) were used. Pain was evaluated with a questionnaire developed by the research team. The study was divided into 4 phases. Pain was evaluated for 4 weeks following the insertion of the first 4 orthodontic wires for each patient (0.016 Supercable, 016 CuNiTi, 016X022 CuNiTi, 019X025 CuNiTi). The same questionnaire was used during each phase and included 6 different time-points following the insertion of each wire (T0: before insertion of orthodontic wire, T1: immediately after the insertion of the wire, T2: 5h after insertion, T3: 24h after insertion, T4: 3 days after insertion, T5: 1 week after insertion, T6: 4 weeks after insertion). The visual analogue scale (VAS) and the short version of Saint-Antoine’s questionnaire were used to evaluate the pain. VAS ratings between groups were compared using the Mann-Whitney U test. Results and Discussion For the first two wires and for all the different time points, there was no statistical difference between both groups (SPEED and Damon). However, at the insertion (T0) of the third wire (016X022 CuNiTi), among patients that reported pain (SPEED 47.1%, Damon 55.6%), Damon caused statistically significantly more pain than SPEED (p=0.018), (VAS mean SPEED=14.14±8.55, Damon=33.85±19.64). Three days after the insertion (T4) of the third wire, among the patients that reported pain (SPEED 23.5%, Damon 33.4%), the pain was statistically significantly higher with Damon than SPEED (p=0.008), (VAS mean SPEED=8.74±4.87, Damon=25.15±9.69). The most frequent use of pain medication occured with the first wire, at time-points T2 (5h) and T3 (24h). There was no statistical difference among the groups in terms of the number of patients taking medication. For the large majority of patients, the pain did not affect their life-style. The most frequently used sensorial words used by the patients to describe their pain were « pulling » (tiraillement), « cramping » (étau), « throbbing» (élancement). The most frequently used affective word was « annoying » (énervant). Conclusion The perception of pain for patients with Damon brackets was significantly higher than for those with the SPEED brackets at the insertion of the third wire and three days after placement of the third wire. More patients took pain médication with the first wire and the majority of patients did not report a change in their quality of life. « Pulling » (tiraillement), « cramping » (étau), « throbbing» (élancement) and « annoying » (énervant) were the words most frequently used by the patients to describe their pain.

Introduction: The objective of this experimental research was to evaluate the slot’s vertical dimension and profile of four different 0.018″ self-ligating brackets and to identify the level of tolerance accepted by manufacturers during the fabrication process. It was then possible to calculate and compare the torque play of those brackets using the measured values and the nominal values. Material and Methods: Twenty-five 0.018″ self-ligating brackets of upper left central incisors from the following manufacturers, Speed® (Strite Industries, Cambridge, Ontario, Canada), InOvationR® (GAC, Bohemia, NY, USA), CarriereLX® (Ortho Organizers, Carlsbad, CA, USA) and SmartClip® (3M Unitek, Monrovia, CA, USA), were evaluated using electron microscopy with 150X images. The height of each bracket was measured at every 100 microns of depth from the lingual wall at five different levels. A Student T test was then used to compare our results with the manufacturer’s stated value of 0.018″. To determine if there was a significant difference between the four manufacturers, analysis of variance (ANOVA) was performed at the significance level of p<0.05. The torque play was then calculated using geometrical formulas. Results: On average, Speed brackets were oversized by 2.7%[MV 0.0185″ (SD:0.002)], InOvationR by 3.7% [MV 0.0187″ (SD:0.002)], CarriereLX by 3.2% [MV 0.0186″ (SD:0.002)] and SmartClipSL by 5.0% [MV 0.0189″ (SD:0.002)]. The height of all brackets was significantly higher than the nominal value of 0.018″ (p<0.001). The slot of SmartClip brackets was significantly larger than those of the other three manufacturers (p<0.001). None of the brackets studied had parallel gingival and occlusal walls; some were convergent and others divergent. These variations can induce a torque play up to 4.5 degrees with a 0.017″x0.025″ wire and 8.0 degrees with a 0.016″x0.022″ wire. Conclusion: All studied brackets were oversized. None of the brackets studied had parallel gingival and occlusal walls and there was no standard between manufacturers for the geometry of their slots. These variations can cause a slight increase of the torque play between the wire and the bracket compared with the nominal value. / Introduction : Cette recherche a été une étude expérimentale conduite en laboratoire visant à évaluer la dimension verticale ainsi que la géométrie de la lumière de différents boîtiers auto-ligaturants populaires de grandeur 0,018″. Par la suite, il a été possible de calculer mathématiquement la perte de torque engendrée par ces variations. Matériel et méthode : Vingt-cinq boîtiers auto-ligaturants d’incisive centrale supérieure gauche de quatre différents manufacturiers, Speed® (Strite Industries, Cambridge, Ontario, Canada), InOvationR® (GAC, Bohemia, NY, USA), CarriereLX® (Ortho Organizers, Carlsbad, CA, USA) et SmartClip SL® (3M Unitek, Monrovia, CA, USA), ont été évalués en utilisant un microscope à balayage électronique à un grossissement de 150X. La hauteur de la lumière a été mesurée à tous les 100 microns de profondeur à cinq différents niveaux, permettant ainsi d’établir sa hauteur moyenne et d’évaluer le parallélisme de ses parois. Le test T de Student a été utilisé pour déterminer si ces valeurs étaient statistiquement significatives comparativement à la valeur de référence de 0,018″. Un test de variance (ANOVA), avec un seuil de signification p<0,05, a été utilisé pour comparer les boîtiers des différents manufacturiers entre eux. La perte de torque a, par la suite, été calculée théoriquement à l’aide de formules géométriques en fonction d’un fil donné. Résultats : En moyenne, la lumière des boîtiers Speed était surdimensionnée de 2,7% [VM : 0,0185″ (DS : 0,002)], InOvationR de 3,7% [VM 0,0187″ (DS : 0,002)], CarriereLX de 3,2% [VM 0,0186″ (DS : 0,002)] et SmartClip SL de 5,0% [VM 0,0189″ (DS : 0,002)]. La hauteur moyenne des quatre types de boîtiers a démontré une différence statistiquement significative par rapport à la valeur de référence de 0,018″ (p<0,001). Il existe également une différence statistiquement significative entre la hauteur moyenne des boîtiers SmartClip et celle des trois autres manufacturiers (p<0,001). Aucun des boîtiers étudiés n’avait les parois gingivales et occlusales parallèles, certaines étaient divergentes, d’autres convergentes. Ces variations peuvent engendrer cliniquement une perte de torque jusqu’à 4,5 degrés avec un fil 0,017″x0,025″ et jusqu’à 8,0 degrés avec un fil 0,016″x0,022″. Conclusion : La lumière de tous les boîtiers étudiés était légèrement surdimensionnée. La géométrie de la lumière variait d’un manufacturier à l’autre, certains boîtiers étaient convergents et d’autres divergents. Ces variations causées par les méthodes de fabrication engendrent une perte de torque supplémentaire par rapport à la valeur nominale.

Magister Chirurgiae Dentium - MChD (Orthodontics) / The aim of the study is to compare the frictional resistance generated between two types of self-ligating brackets; Smart-Clip Metal SL (3M Unitek) and Damon Clear SL (Ormco), with conventional stainless steel brackets, Victory Series (3M Unitek) when coupled with various stainless steel and nickel-titanium archwires. Materials and Methods: All brackets had a 0.022" slot and tested using three archwires: 0.016" nickel-titanium, 0.019 x 0.025" nickel-titanium and 0.019 x 0.025" stainless steel archwires. Friction was evaluated for the upper right quadrant of the typodont. For each testing procedure, new brackets and archwire was employed to eliminate the influence of wear. Results: The mean results showed that the Smart-Clip self-ligating brackets generated significantly lower friction than both the Damon Clear self-ligating brackets and Victory Series brackets. However, the analysis of the various bracket-archwire combinations displayed that Damon Clear SL brackets generated the lowest friction when tested with 0.016" round nickeltitanium archwire and significantly higher friction than Smart-Clip and Victory Series brackets when tested with 0.019 x 0.025" stainless steel rectangular archwires. All brackets showed higher frictional forces as the wire size increased. Clinical relevance: The production of high levels of friction during orthodontic sliding mechanics presents a clinical challenge to the orthodontists. The generation of high levels of friction may reduce the effectiveness of the mechanics, decrease tooth movement efficiency and further complicate anchorage control. The amount of friction is variable in the orthodontic system and can be altered somewhat by the orthodontist's choices.

Magister Scientiae Dentium - MSc(Dent) (Orthodontics) / Orthodontic treatment has the ability to improve the aesthetics and the function of patients. In order to create space, orthodontic treatment often requires removal of teeth. The most common teeth removed for orthodontic treatment are the premolars. It has become popular to remove second premolars in certain cases where the soft tissue profile should not be altered. The Damon self-ligating orthodontic system is renowned for not requiring dental extractions in the majority of cases. The effect of extractions on the soft tissue profile of patients, in conjunction with using the Damon system, has therefore not been researched. It is important to understand the effect that orthodontic treatment and extractions can have on the soft tissue profile of patients. This effect can accurately be determined by making use of the soft tissue cephalometric analysis, developed by Dr Reed A. Holdaway in 1983.

Introduction: The objective of this experimental research was to evaluate the slot’s vertical dimension and profile of four different 0.018″ self-ligating brackets and to identify the level of tolerance accepted by manufacturers during the fabrication process. It was then possible to calculate and compare the torque play of those brackets using the measured values and the nominal values. Material and Methods: Twenty-five 0.018″ self-ligating brackets of upper left central incisors from the following manufacturers, Speed® (Strite Industries, Cambridge, Ontario, Canada), InOvationR® (GAC, Bohemia, NY, USA), CarriereLX® (Ortho Organizers, Carlsbad, CA, USA) and SmartClip® (3M Unitek, Monrovia, CA, USA), were evaluated using electron microscopy with 150X images. The height of each bracket was measured at every 100 microns of depth from the lingual wall at five different levels. A Student T test was then used to compare our results with the manufacturer’s stated value of 0.018″. To determine if there was a significant difference between the four manufacturers, analysis of variance (ANOVA) was performed at the significance level of p<0.05. The torque play was then calculated using geometrical formulas. Results: On average, Speed brackets were oversized by 2.7%[MV 0.0185″ (SD:0.002)], InOvationR by 3.7% [MV 0.0187″ (SD:0.002)], CarriereLX by 3.2% [MV 0.0186″ (SD:0.002)] and SmartClipSL by 5.0% [MV 0.0189″ (SD:0.002)]. The height of all brackets was significantly higher than the nominal value of 0.018″ (p<0.001). The slot of SmartClip brackets was significantly larger than those of the other three manufacturers (p<0.001). None of the brackets studied had parallel gingival and occlusal walls; some were convergent and others divergent. These variations can induce a torque play up to 4.5 degrees with a 0.017″x0.025″ wire and 8.0 degrees with a 0.016″x0.022″ wire. Conclusion: All studied brackets were oversized. None of the brackets studied had parallel gingival and occlusal walls and there was no standard between manufacturers for the geometry of their slots. These variations can cause a slight increase of the torque play between the wire and the bracket compared with the nominal value. / Introduction : Cette recherche a été une étude expérimentale conduite en laboratoire visant à évaluer la dimension verticale ainsi que la géométrie de la lumière de différents boîtiers auto-ligaturants populaires de grandeur 0,018″. Par la suite, il a été possible de calculer mathématiquement la perte de torque engendrée par ces variations. Matériel et méthode : Vingt-cinq boîtiers auto-ligaturants d’incisive centrale supérieure gauche de quatre différents manufacturiers, Speed® (Strite Industries, Cambridge, Ontario, Canada), InOvationR® (GAC, Bohemia, NY, USA), CarriereLX® (Ortho Organizers, Carlsbad, CA, USA) et SmartClip SL® (3M Unitek, Monrovia, CA, USA), ont été évalués en utilisant un microscope à balayage électronique à un grossissement de 150X. La hauteur de la lumière a été mesurée à tous les 100 microns de profondeur à cinq différents niveaux, permettant ainsi d’établir sa hauteur moyenne et d’évaluer le parallélisme de ses parois. Le test T de Student a été utilisé pour déterminer si ces valeurs étaient statistiquement significatives comparativement à la valeur de référence de 0,018″. Un test de variance (ANOVA), avec un seuil de signification p<0,05, a été utilisé pour comparer les boîtiers des différents manufacturiers entre eux. La perte de torque a, par la suite, été calculée théoriquement à l’aide de formules géométriques en fonction d’un fil donné. Résultats : En moyenne, la lumière des boîtiers Speed était surdimensionnée de 2,7% [VM : 0,0185″ (DS : 0,002)], InOvationR de 3,7% [VM 0,0187″ (DS : 0,002)], CarriereLX de 3,2% [VM 0,0186″ (DS : 0,002)] et SmartClip SL de 5,0% [VM 0,0189″ (DS : 0,002)]. La hauteur moyenne des quatre types de boîtiers a démontré une différence statistiquement significative par rapport à la valeur de référence de 0,018″ (p<0,001). Il existe également une différence statistiquement significative entre la hauteur moyenne des boîtiers SmartClip et celle des trois autres manufacturiers (p<0,001). Aucun des boîtiers étudiés n’avait les parois gingivales et occlusales parallèles, certaines étaient divergentes, d’autres convergentes. Ces variations peuvent engendrer cliniquement une perte de torque jusqu’à 4,5 degrés avec un fil 0,017″x0,025″ et jusqu’à 8,0 degrés avec un fil 0,016″x0,022″. Conclusion : La lumière de tous les boîtiers étudiés était légèrement surdimensionnée. La géométrie de la lumière variait d’un manufacturier à l’autre, certains boîtiers étaient convergents et d’autres divergents. Ces variations causées par les méthodes de fabrication engendrent une perte de torque supplémentaire par rapport à la valeur nominale.

Introduction Cette recherche constitue une étude clinique descriptive, visant à évaluer la douleur durant le traitement orthodontique avec boîtiers auto-ligaturants passifs et actifs. Matériel et méthode L'étude a été effectuée chez 39 patients (18 garçons, 21 filles), âge moyen 14 (entre 11 et 19 ans). Deux types de boîtiers auto-ligaturants ont été utilisés (SPEED n=20 et Damon n=19). Pour évaluer la douleur, un questionnaire a été élaboré par l'équipe de recherche. L’étude comportait 4 phases, c’est-à-dire l’évaluation de la douleur suite à l’insertion des 4 premiers fils orthodontiques du traitement de chaque patient (0.016 Supercable, 016 CuNiTi, 016X022 CuNiTi, 019X025 CuNiTi). Le même questionnaire était utilisé lors de chaque phase et le questionnaire comprenait 6 différents temps (T0: avant l’insertion du fil orthodontique, T1: immédiatement suite à l’insertion du fil, T2: 5h après l’insertion, T3: 24h après l’insertion, T4: 3 jours après l’insertion, T5: une semaine après l’insertion, T6: 4 semaines après l’insertion) suite à l’insertion de chaque fil. L’échelle visuelle analogue (EVA) et la version courte du questionnaire de Saint-Antoine ont été utilisés afin d’évaluer la douleur. Les données des EVA entre les groupes ont été comparées en utilisant le U test Mann-Whitney. Résultats et discussion Pour les deux premiers fils et pour tous les temps étudiés, il n’y avait pas de différence statistiquement significative entre les deux groupes (SPEED et Damon). Cependant, au moment de l’insertion (T0) du troisième fil (016X022 CuNiTi), parmi les patients ayant rapporté de la douleur (SPEED 47.1%, Damon 55.6%), le groupe Damon a rapporté une douleur significativement plus élevée que le groupe SPEED (p=0.018), (EVA moyenne SPEED=14.14±8.55, Damon=33.85±19.64). Trois jours après l’insertion du troisième fil, toujours parmi les patients ayant rapporté de la douleur (SPEED 23.5%, Damon 33.4%), la douleur était significativement plus élevée chez le groupe Damon que chez le groupe SPEED (p=0.008), (EVA moyenne SPEED=8.74±4.87, Damon=25.15±9.69). La plupart des analgésiques ont été pris suite à la pose du premier fil au temps T2 (5h) et T3 (24h). Il n’y avait pas de différence statistiquement significative entre les groupes en ce qui a trait au nombre de patients qui prenaient des analgésiques. La douleur n’a pas affecté le style de vie pour la grande majorité des patients. Les mots descriptifs sensoriels « tiraillement », « étau » et « élancement » et le mot affectif « énervant » étaient le plus souvent utilisés. Conclusion Les patients du groupe Damon ont ressenti significativement plus de douleur que les patients du groupe SPEED à l’insertion du troisième fil et trois jours suite à l’insertion. Plus de patients ont pris des médicaments pour la douleur avec le premier fil et le style de vie n’était pas affecté pour une majorité de patients. « Tiraillement », « étau », « élancement » et « énervant » étaient les mots descriptifs les plus utilisés par les patients pour décrire leur douleur. / Introduction This research is a descriptive clinical study designed to assess pain during orthodontic treatment with self-ligating brackets. Materials and methods This study was comprised of 39 patients (18 male, 21 female), mean age of 14 (range 11 to 19 yo). Two types of self-ligating brackets (SPEED n=20 and Damon n=19) were used. Pain was evaluated with a questionnaire developed by the research team. The study was divided into 4 phases. Pain was evaluated for 4 weeks following the insertion of the first 4 orthodontic wires for each patient (0.016 Supercable, 016 CuNiTi, 016X022 CuNiTi, 019X025 CuNiTi). The same questionnaire was used during each phase and included 6 different time-points following the insertion of each wire (T0: before insertion of orthodontic wire, T1: immediately after the insertion of the wire, T2: 5h after insertion, T3: 24h after insertion, T4: 3 days after insertion, T5: 1 week after insertion, T6: 4 weeks after insertion). The visual analogue scale (VAS) and the short version of Saint-Antoine’s questionnaire were used to evaluate the pain. VAS ratings between groups were compared using the Mann-Whitney U test. Results and Discussion For the first two wires and for all the different time points, there was no statistical difference between both groups (SPEED and Damon). However, at the insertion (T0) of the third wire (016X022 CuNiTi), among patients that reported pain (SPEED 47.1%, Damon 55.6%), Damon caused statistically significantly more pain than SPEED (p=0.018), (VAS mean SPEED=14.14±8.55, Damon=33.85±19.64). Three days after the insertion (T4) of the third wire, among the patients that reported pain (SPEED 23.5%, Damon 33.4%), the pain was statistically significantly higher with Damon than SPEED (p=0.008), (VAS mean SPEED=8.74±4.87, Damon=25.15±9.69). The most frequent use of pain medication occured with the first wire, at time-points T2 (5h) and T3 (24h). There was no statistical difference among the groups in terms of the number of patients taking medication. For the large majority of patients, the pain did not affect their life-style. The most frequently used sensorial words used by the patients to describe their pain were « pulling » (tiraillement), « cramping » (étau), « throbbing» (élancement). The most frequently used affective word was « annoying » (énervant). Conclusion The perception of pain for patients with Damon brackets was significantly higher than for those with the SPEED brackets at the insertion of the third wire and three days after placement of the third wire. More patients took pain médication with the first wire and the majority of patients did not report a change in their quality of life. « Pulling » (tiraillement), « cramping » (étau), « throbbing» (élancement) and « annoying » (énervant) were the words most frequently used by the patients to describe their pain.

Magister Scientiae Dentium - MSc(Dent) / Background and aim: Managing orthodontic pain traditionally involves the prescription of non-steroidal anti-inflammatory drugs combined with other analgesic medication. Sugar-free chewing gum has been advocated in the control of orthodontic pain due to its mechanical and physiological effects on periodontal tissue; however, the literature is scant. The ‘placebo effect’ that conventional sugar-free chewing gum may have in the relief of orthodontic pain has not been documented. The aim of this study was to compare the effectiveness of conventional sugar-free chewing gum in reducing orthodontic pain associated with fixed appliances with a placebo (sugar-free sweets) medicament. Objectives: The objectives of the study were to determine if there were differences in pain reporting between the sugar-free chewing gum and the placebo, to ascertain whether gender influenced pain scores and to observe any differences in pain reporting between different orthodontic techniques.

<b>Introduction</b>: Today one of the primary goals of any kind of dental treatment is the achievement of balanced smile aesthetics, as patients increasingly attend dental clinics to improve their appearance. The main aim of the present study was to assess and compare the smile aesthetics created by the use of two orthodontic bracket systems (self-ligating vs. conventional ligating) as a part of analysing secondary outcomes of two randomised clinical trials comparing between these two systems. <b>Methodology</b>: The assessment of smile aesthetics was done by analysing and scoring post-orthodontic treatment 125 frontal smile photographs subjectively and objectively. The subjective evaluation was performed by 20 dental professionals and 20 laypeople, while the objective assessment was done by one principal examiner using a group of smile aesthetics parameters. <b>Statistical analysis</b>: Multiple regression statistical analyses were performed to test the association between subjective and objective assessment of smile aesthetics in order to find the significant smile aesthetics predictors and assess the effect of the bracket type (self-ligating vs conventional) on the resulting smile aesthetics. <b>Results</b>: The finding from this research shows that the bracket type was not an important smile aesthetics factor in all the statistical models, although there are other important smile aesthetics factors as there was a significant correlation between the subjective and objective assessment of smile aesthetics parameters (Pearson’s correlation coefficients “r” > 0.50). <b>Conclusion</b>: There is insufficient evidence to reject the null hypotheses of no significant difference in the smile aesthetics created by the two orthodontic bracket systems. An Orthodontic Smile Aesthetics Rating (OSAR) tool has been developed.

O objetivo principal do estudo é comparar o teste em 3 pontos com braquetes com o teste de resistência ao deslizamento utilizando um novo dispositivo que realiza a mensuração simultânea do coeficiente de atrito, das forças e dos momentos nos braquetes de ancoragem e da força de desativação no braquete desalinhado, exercidos por fios ortodônticos. Os objetivos secundários foram desenvolver o dispositivo e comparar, no teste em 3 pontos: (i) a influência, nas grandezas e no coeficiente de atrito cinético, da variação da simetria nas distâncias inter-braquetes, do tipo de braquete de ancoragem (canino ou 2º pré-molar), do deslocamento (3 ou 5mm) do braquete central, do sentido do desalinhamento (vestibular ou lingual) do braquete central e da marca de fio-braquete; (ii) as 3 formas de cálculo do coeficiente de atrito cinético; (iii) os 10 ciclos, para vestibular ou lingual, para verificar se eles são semelhantes ou não entre si. Foram utilizados braquetes autoligáveis (dentes 13, 14 e 15) e fios 0.014\'\' NiTi e CuNiTi das marcas Aditek e Ormco. O teste de resistência ao deslizamento foi realizado no desalinhamento lingual, nos dois deslocamentos e na configuração simétrica. O teste em 3 pontos com braquetes foi realizado no desalinhamento lingual e vestibular, nos dois deslocamentos e na configuração simétrica e assimétrica. Por meio da ANOVA, foram comparados, entre os dois tipos de teste: (A) as grandezas e o coeficiente de atrito e (B) o coeficiente de atrito gerado apenas no braquete de 2º pré-molar. Utilizando-se do mesmo teste estatístico foram comparados, no teste em 3 pontos com braquetes: (A) na configuração simétrica, algumas grandezas e o coeficiente de atrito advindos da variação da marca de fio-braquete, do deslocamento, do desalinhamento e do tipo de braquete; (B) algumas grandezas e o coeficiente de atrito gerados na configuração simétrica e assimétrica; (C) os valores das 3 formas de cálculo do coeficiente de atrito na configuração simétrica; e (D) algumas grandezas e o coeficiente de atrito encontrados nos 10 ciclos. Resultados: (A) a maioria dos valores das grandezas e do coeficiente de atrito gerados pelos dois tipos de teste foram diferentes estatisticamente; (B) o braquete de 2º pré-molar apresentou valores de coeficiente de atrito diferentes entre os dois tipos de teste; (C) na configuração simétrica, as variáveis foram estatisticamente significantes na maioria dos casos para as grandezas analisadas e para o coeficiente de atrito; (D) houve diferença entre a configuração simétrica e assimétrica; (E) o coeficiente de atrito baseado nas duas normais e na força de atrito se aproximou mais da realidade clínica e foi sensível à variação da geometria da relação fio-braquete; e (F) os 10 ciclos para lingual foram semelhantes entre si em 70% dos casos e os 10 ciclos para vestibular foram diferentes em 57% dos casos. Conclusões: o teste em 3 pontos com braquetes é diferente do teste de resistência ao deslizamento; a variação das configurações geométricas e da marca de fio-braquete pode influenciar nos valores das grandezas e do coeficiente de atrito cinético; os 10 ciclos para lingual foram mais semelhantes entre si que os 10 ciclos para vestibular. / The main objective of the study is to compare the three-bracket bending test with the resistance to sliding test using a new device that performs simultaneous measurement of coefficient of friction, the forces and moments on the anchor brackets and deactivation force in misaligned bracket, exercised by orthodontic wires. Secondary objectives were to develop the device and compare, in the three-bracket bending test: (i) the influence, on the physical quantities and on the kinetic friction coefficient, of the variation of the symmetry in the inter-bracket distance, of the type of anchor bracket (canine or 2nd premolar), of displacement (3 or 5mm) and misalignment (buccal or lingual) of the central bracket, and of the wire and bracket brand; (ii) the three ways to calculate the coefficient of kinetic friction; (iii) the 10 cycles, for buccal or lingual, to see if they are similar or not. Self-ligating brackets were used (teeth 13, 14 and 15) and wires 0.014 \'\' NiTi and CuNiTi of Aditek and Ormco brands. The resistance to sliding test was conducted on the lingual misalignment, on both displacements and on symmetrical configuration. The three-bracket bending test was held at the lingual and vestibular misalignment, at both displacements and at the symmetrical and asymmetrical configuration. Through ANOVA, were compared, between the two types of tests: (A) the quantities and the coefficient of friction and (B) the coefficient of friction generated only in the second premolar bracket. Using the same statistical test were compared, in three-bracket bending test: (A) in symmetrical configuration, the quantities and the coefficient of friction arising from the variation in the wire and bracket brands, displacement, misalignment and the type of bracket; (B) the quantities and the coefficient of friction generated by the symmetric and asymmetric configuration; (C) the values of the three ways of calculating friction coefficient; and (D) the quantities and the coefficient of friction encountered in 10 cycles. Results: (A) most of the values of the quantities and the coefficient of friction generated by the two types of test were statistically different; (B) the 2nd premolar bracket showed different friction coefficient values between the two types of test; (C) in the symmetrical configuration, the variables were statistically significant in the most of cases for quantities and the friction coefficient; (D) was found difference between symmetric and asymmetric configuration; (E) the friction coefficient based on both normal forces and frictional force was closer to the clinical reality and was sensitive to variations in the geometry of the wire-bracket relationship; and (F) the 10 cycles for lingual were similar in 70% of cases and the 10 cycles for buccal desalignment were different in 57% of cases. Conclusions: The three-bracket bending test is different from the resistance to sliding test; the variation of geometric configurations and wire and bracket brands may influence the values of the quantities and the coefficient of kinetic friction; the 10 cycles for lingual were more similar to each other than the 10 cycles for buccal.