Effect of poly-L-lactic acid and polydioxanone biostimulators on type I and III collagen biosynthesis.

OBJECTIVE: Safe, effective, and biocompatible minimally invasive procedures with the potential to stimulate collagen production have been made to recover dermal thickness and skin quality. The main of this animal model experiment was to observe the effect of poly-L-lactic acid (PLLA) and polydioxanone (PDO) biostimulators in collagen I and III after hypodermal injection. METHODOLOGY: Sixteen adult female rats (Wistar) were randomized into four groups and had dorsal treatment with: G1: hypodermic subcision (HS) only; G2: HS and PLLA hypodermic injection (HI), G3: HS and PDO HI; G4: Control, with no treatment. RESULTS: In histochemical, it was observed hypodermal and dermal tissue in more organized thickness in G3 and in G4 when compared to G1 and G2. There was few difference in G1 compared to G4. The tissue of G2 showed irregularities in the arrangement of collagen fibers, less defined structure and lower distribution of type I collagen compared to the other groups. There is a greater tendency for the proportions of type III collagen among tissues treated with both biostimulators (G2 and G3). PLLA and PDO had relatively similar percentages of collagen when compared to G4. The amount of type I collagen was higher in tissues treated with subcision, while type III collagen was higher in tissues treated with both biostimulators. CONCLUSION: G3 showed better performance in collagen production, although small, when compared with G2.

Assessment of patients' knowledge and preferences for the use of orthodontic aligners.

OBJECTIVE: To evaluate the knowledge and preference of patients treated at a Dental School in Jaraguá do Sul, Brazil, about using aligners and the reasons for choosing this device as a treatment option. DESIGN: A cross-sectional study. PARTICIPANTS: A total of 82 participants aged 18-45 years recruited at a screening clinic. METHODS: A questionnaire was completed in person using a tablet with digital forms. RESULTS: Almost half of the participants (49%) knew about aligners; 40% were aged 18-24 years, and 77% were female. When observing the images of the types of orthodontic appliances, the aligners had an acceptance rate of 80%. Among the reasons that led to the preference for choosing aligners, 68% cited aesthetics and 42% comfort. CONCLUSION: Recently, clear aligners have become a popular choice for orthodontic treatment, particularly among adults. Despite their popularity and effectiveness, many patients still need more information about aligner treatment. Over half of the respondents did not know what orthodontic aligners were. Younger participants had more knowledge about aligners than older participants. Patients still need more knowledge about the types of appliances available for orthodontic treatment. When presented with images of the kinds of devices available, almost 80% of participants showed greater satisfaction with aligners.

Comparative cephalometric study of the airways between different ethnic groups with normal occlusion.

OBJECTIVE: This study aimed to compare the nasopharynx and oropharynx airway dimensions of Caucasians, Blacks, Japanese, Japanese Brazilians, and Black Caucasians. METHODS: A sample of 216 lateral radiographs of untreated young Brazilian subjects (mean age of 12.94 years; SD 0.88) were divided into five groups: Black Caucasian, Black, Caucasian, Japanese, and Japanese Brazilian. Lateral radiographs were used to measure the oropharynx (from the midpoint on the soft palate to the closest point on the anterior pharyngeal wall) and the nasopharynx (from the intersection of the posterior border of the tongue and the inferior border of the mandible to the closest point on the posterior pharyngeal wall). Analyses of variance (ANOVA) and Tukey's test were performed (p< 0.05). RESULTS: The linear dimension of the oropharynx was similar among the different ethnic groups. Caucasian individuals presented a significantly greater linear dimension of the nasopharynx than Black Caucasian and Black individuals. CONCLUSIONS: All the groups had similar buccopharyngeal values. However, Caucasian individuals had significantly higher values when compared to Black Caucasians and Black individuals.

Efficacy of products for bleaching and whitening under orthodontic brackets.

INTRODUCTION: Many patients wearing orthodontic appliances request alterations in the shade of their teeth during orthodontic treatment. OBJECTIVE: This study aimed to evaluate the efficacy of different products for bleaching and whitening under orthodontic brackets. METHODS: Seventy bovine incisors were randomly divided into five groups (n = 14): C) non-whitening toothpaste (control); WTsi) hydrated silica whitening toothpaste; WThp) 2% hydrogen peroxide whitening toothpaste; OB) in-office bleaching; and HB) at-home bleaching. Two buccal surface areas were evaluated using the Easyshade spectrophotometer: under the metal bracket (experimental) and around the bracket (control). The paired t-test, ANOVA, and Tukey tests were applied for statistical analysis. RESULTS: Intragroup comparisons showed that in groups C, WThp and HB, there were statistically significant differences in the enamel color changes (ΔEab) between under and around the bracket areas (C - under bracket = 7.97 ± 2.35, around bracket = 2.86 ± 0.81, p< 0.01; WThp - under bracket = 4.69 ± 2.98, around bracket = 2.05 ± 1.41, p< 0.01; HB - under bracket = 7.41 ± 2.89, around bracket: 9.86 ± 3.32, p= 0.02). Groups WTsi, OB and HB presented similar perception of tooth whiteness (ΔWID) between the tested areas. Intergroup comparisons demonstrated that under the bracket area, the color change (ΔEab) was similar for all groups, except WThp (C = 7.97 ± 2.35; WTsi = 8.54 ± 3.63; WThp = 4.69 ± 2.98; OB = 9.31 ± 4.32; HB = 7.41 ± 2.89; p< 0.01). CONCLUSIONS: The dental color changes were effective for the products tested in groups WTsi, OB and HB in the presence of metallic orthodontic brackets.

Miniscrew insertion sites of infrazygomatic crest and mandibular buccal shelf in different vertical craniofacial patterns: A cone-beam computed tomography study.

OBJECTIVE: To identify optimal areas for the insertion of extra-alveolar miniscrews into the infrazygomatic crest (IZC) and mandibular buccal shelf (MBS), using cone beam computed tomography (CBCT) imaging in patients with different craniofacial patterns. METHODS: CBCT reconstructions of untreated individuals were used to evaluate the IZC and MBS areas. The participants were divided into three groups, based on the craniofacial pattern, namely, brachyfacial (n = 15; mean age, 23.3 years), mesofacial (n = 15; mean age, 19.24 years), and dolichofacial (n = 15; mean age, 17.79 years). In the IZC, the evaluated areas were at 11, 13, and 15 mm above the buccal cusp tips of the right and left first molars. In the MBS, the evaluated areas were at the projections of the first molars' distal roots and second molars' mesial and distal roots, at a 4- and 8-mm distance from the cementoenamel junction. Intergroup comparisons were performed with analysis of variance and the Tukey test. RESULTS: There was no statistically significant difference in the IZC bone thickness among the groups. For MBS bone availability, some comparisons revealed no difference; meanwhile, other comparisons revealed increased MBS bone thickness in the brachyfacial (first molars distal roots) and dolichofacial (second molars mesial and distal roots) patterns. CONCLUSIONS: There was no significant difference in the IZC bone thickness among the groups. The facial skeletal pattern may affect the availability of ideal bone thickness for the insertion of extra-alveolar miniscrews in the MBS region; however, this variability is unlikely to be clinically meaningful.

Evaluation of Mandibular First Molars' Axial Inclination and Alveolar Morphology in Different Facial Patterns: A CBCT Study.

OBJECTIVE: The purpose of this study was to evaluate and compare the axial inclination of the mandibular first molars and their respective bone morphology among individuals with different facial patterns. MATERIALS AND METHODS: The sample comprised the cone beam computed tomographies (CBCTs) of 58 subjects divided into three groups according to the facial patterns: 18 brachyfacial (Group 1), with a mean age of 21.58 years; 23 mesofacial (Group 2), with a mean age of 19.14 years; and 17 dolichofacial subjects (Group 3), with a mean age of 19.09 years. Eight variables were evaluated on CBCT scans of each subject: buccal and lingual mandibular height, cervical and middle mandibular width, inclination of mandibular body, inclination of the mandibular molar buccal surface, molar width, molar angulation and tooth/bone angle. Intergroup comparisons were performed with one-way analysis of variance followed by Tukey tests. RESULTS: Buccal mandibular height presented statistically significant difference in the three facial patterns. Lingual mandibular height and mandibular inclination showed to be statistically and significantly smaller in brachyfacial subjects than in the other two groups. Mandibular width presented a statistically significant difference between brachyfacial and mesofacial groups. Negative correlations could be observed between the facial pattern and the buccal and lingual mandibular heights and inclination of the mandibular body. CONCLUSION: Buccal mandibular height was significantly and progressively larger in brachyfacial, mesofacial, and dolichofacial subjects. Lingual mandibular height was significantly smaller in brachyfacial than in mesofacial and dolichofacial subjects. Mandibular width was significantly thicker in brachyfacial than in mesofacial subjects. Brachyfacial subjects had smaller mandibular inclination than mesofacial and dolichofacial subjects.

Comparative cephalometric study of the airways between different ethnic groups with normal occlusion

ABSTRACT Objective: This study aimed to compare the nasopharynx and oropharynx airway dimensions of Caucasians, Blacks, Japanese, Japanese Brazilians, and Black Caucasians. Methods: A sample of 216 lateral radiographs of untreated young Brazilian subjects (mean age of 12.94 years; SD 0.88) were divided into five groups: Black Caucasian, Black, Caucasian, Japanese, and Japanese Brazilian. Lateral radiographs were used to measure the oropharynx (from the midpoint on the soft palate to the closest point on the anterior pharyngeal wall) and the nasopharynx (from the intersection of the posterior border of the tongue and the inferior border of the mandible to the closest point on the posterior pharyngeal wall). Analyses of variance (ANOVA) and Tukey's test were performed (p< 0.05). Results: The linear dimension of the oropharynx was similar among the different ethnic groups. Caucasian individuals presented a significantly greater linear dimension of the nasopharynx than Black Caucasian and Black individuals. Conclusions: All the groups had similar buccopharyngeal values. However, Caucasian individuals had significantly higher values when compared to Black Caucasians and Black individuals.

RESUMO Objetivo: Este estudo teve como objetivo comparar as dimensões das vias aéreas da nasofaringe e da bucofaringe de leucodermas, melanodermas, xantodermas, feodermas e nipo-brasileiros. Material e métodos: Uma amostra de 216 telerradiografias laterais de jovens brasileiros não tratados (idade média de 12,94 anos; DP 0,88) foi dividida em cinco grupos: melanodermas, leucodermas, xantodermas, feodermas e nipo-brasileiros. As telerradiografias foram utilizadas para medir a bucofaringe (do ponto médio do palato mole até o ponto mais próximo da parede anterior da faringe) e a nasofaringe (da intersecção da borda posterior da língua e da borda inferior da mandíbula até o ponto mais próximo). Foram realizadas análises de variância (ANOVA) e teste de Tukey (p < 0,05). Resultados: A dimensão linear da bucofaringe foi semelhante entre os diferentes grupos étnicos. Indivíduos leucodermas apresentaram dimensão linear da nasofaringe significativamente maior do que indivíduos feodermas e melanodermas. Conclusões: Todos os grupos apresentaram valores da bucofaringe semelhantes. No entanto, os indivíduos leucodermas apresentaram valores significantemente maiores, quando comparados aos feodermas e melanodermas.

Comparison of deflection forces of esthetic archwires combined with ceramic brackets.

Coated archwires and ceramic brackets have been developed to improve facial esthetics during orthodontic treatment. However, their mechanical behavior has been shown to be different from metallic archwires and brackets. Therefore, the aim of this study was to compare the deflection forces in coated nickel-titanium (NiTi) and esthetic archwires combined with ceramic brackets. Material and Methods Non-coated NiTi (NC), rhodium coated NiTi (RC), teflon coated NiTi (TC), epoxy coated NiTi (EC), fiber-reinforced polymer (FRP), and the three different conventional brackets metal-insert polycrystalline ceramic (MI-PC), polycrystalline ceramic (PC) and monocrystalline ceramic (MC) were used. The specimens were set up on a clinical simulation device and evaluated in a Universal Testing Machine (Instron). An acrylic device, representative of the right maxillary central incisor was buccolingually activated and the unloading forces generated were recorded at 3, 2, 1 and 0.5 mm. The speed of the testing machine was 2 mm/min. ANOVA and Tukey tests were used to compare the different archwires and brackets. Results The brackets presented the following decreasing force ranking: monocrystalline, polycrystalline and polycrystalline metal-insert. The decreasing force ranking of the archwires was: rhodium coated NiTi (RC), non-coated NiTi (NC), teflon coated NiTi (TC), epoxy coated NiTi (EC) and fiber-reinforced polymer (FRP). At 3 mm of unloading the FRP archwire had a plastic deformation and produced an extremely low force in 2; 1 and 0.5 mm of unloading. Conclusion Combinations of the evaluated archwires and brackets will produce a force ranking proportional to the combination of their individual force rankings.

Efficacy of products for bleaching and whitening under orthodontic brackets

ABSTRACT Introduction: Many patients wearing orthodontic appliances request alterations in the shade of their teeth during orthodontic treatment. Objective: This study aimed to evaluate the efficacy of different products for bleaching and whitening under orthodontic brackets. Methods: Seventy bovine incisors were randomly divided into five groups (n = 14): C) non-whitening toothpaste (control); WTsi) hydrated silica whitening toothpaste; WThp) 2% hydrogen peroxide whitening toothpaste; OB) in-office bleaching; and HB) at-home bleaching. Two buccal surface areas were evaluated using the Easyshade spectrophotometer: under the metal bracket (experimental) and around the bracket (control). The paired t-test, ANOVA, and Tukey tests were applied for statistical analysis. Results: Intragroup comparisons showed that in groups C, WThp and HB, there were statistically significant differences in the enamel color changes (ΔEab) between under and around the bracket areas (C - under bracket = 7.97 ± 2.35, around bracket = 2.86 ± 0.81, p< 0.01; WThp - under bracket = 4.69 ± 2.98, around bracket = 2.05 ± 1.41, p< 0.01; HB - under bracket = 7.41 ± 2.89, around bracket: 9.86 ± 3.32, p= 0.02). Groups WTsi, OB and HB presented similar perception of tooth whiteness (ΔWID) between the tested areas. Intergroup comparisons demonstrated that under the bracket area, the color change (ΔEab) was similar for all groups, except WThp (C = 7.97 ± 2.35; WTsi = 8.54 ± 3.63; WThp = 4.69 ± 2.98; OB = 9.31 ± 4.32; HB = 7.41 ± 2.89; p< 0.01). Conclusions: The dental color changes were effective for the products tested in groups WTsi, OB and HB in the presence of metallic orthodontic brackets.

RESUMO Introdução: Durante o tratamento ortodôntico, muitos pacientes solicitam, também, alteração na cor dos seus dentes. Objetivo: O presente estudo avaliou diferentes produtos clareadores e branqueadores, quanto à sua eficácia sob os braquetes ortodônticos. Métodos: 70 incisivos bovinos foram aleatoriamente divididos em cinco grupos (n = 14): C) dentifrício não branqueador (controle); WTsi) dentifrício branqueador com sílica hidratada; WThp) dentifrício branqueador com peróxido de hidrogênio a 2%; OB) clareamento no consultório e HB) clareamento caseiro. Usando um espectrofotômetro Easyshade, foram avaliadas duas áreas na superfície vestibular dos dentes: sob o braquete (experimental) e ao redor do braquete (controle). Para análise estatística, foram usados os testest pareado, ANOVA e Tukey. Resultados: As comparações intragrupos demonstraram que, nos grupos C, WThp e HB, ocorreram diferenças estatisticamente significativas nas alterações de cor do esmalte (ΔEab) entre as áreas sob o braquete e ao redor do braquete (C: sob o braquete = 7,97 ± 2,35, ao redor do braquete = 2,86 ± 0,81, p< 0,01; WThp: sob o braquete = 4,69 ± 2,98, ao redor do braquete = 2,05 ± 1,41, p< 0,01; HB: sob o braquete = 7,41 ± 2,89, ao redor do braquete = 9,86 ± 3,32, p= 0,02). Os grupos WTsi, OB e HB demonstraram semelhanças na percepção do clareamento (ΔWID) entre as áreas avaliadas. As comparações intergrupos demonstraram que, nas áreas sob os braquetes, as alterações de cor (ΔEab) foram semelhantes para os grupos, com exceção do WThp (C = 7,97 ± 2,35; WTsi = 8,54 ± 3,63; WThp = 4,69 ± 2,98; OB = 9,31 ± 4,32; HB = 7,41 ± 2,89; p< 0,01). Conclusões: As alterações na cor dos dentes foram efetivas para os procedimentos testados nos grupos WTsi, OB e HB na presença de braquetes metálicos ortodônticos.

Ação clareadora e microbiológica do enxaguante bucal com peróxido de hidrogênio: ensaio clínico / Whitening and microbiological action of mouthwash with hydrogen peroxide: clinical trial

Introdução: os enxaguantes bucais clareadores tem sido muito utilizados, porém sua eficiência e efeitos colaterais trazem questionamentos. Objetivo: este ensaio clínico teve como objetivo avaliar se o enxaguante bucal clareador, contendo peróxido de hidrogênio a 1,5%, apresenta ação clareadora e se há algum efeito secundário na cavidade bucal. Metodologia: foram selecionados 10 voluntários com idade média de 21,5 anos, submetidos a avaliação da cor dos dentes com auxílio do espectrômetro em 3 momentos: inicial; com 15 e com 30 dias de uso do enxaguante. A avaliação dos efeitos colaterais foi realizada a partir da coleta de saliva estimulada em 4 momentos: antes e depois ao primeiro uso do produto, com 15 e com 30 dias, e realizadas as análises laboratoriais: fluxo salivar; pH; quantidade de Streptococcus mutans e de Lactobacillus. A normalidade dos dados foi verificada pelo teste de Shapiro-Wilk, comparação de cor pelo teste t dependente, comparação dos microrganismos pelos testes ANOVA de medidas repetida e Tukey. Resultados: as análises de cor dos dentes não evidenciaram nenhuma alteração significativa em nenhum dos tempos investigados. No fluxo salivar, pH e Lactobacillus não houveram alterações significativas. Na quantidade de Streptococcus mutans notou-se um aumento significativo quando comparado os valores após o primeiro uso e com 30 dias. Conclusão: a solução de enxague bucal contendo peróxido de hidrogênio a 1,5% não apresentou alteração significativa na coloração dos dentes e nenhum efeito colateral significativo na atividade cariogênica de acordo com os testes e períodos avaliados.

Introduction: whitening mouthwashes have been widely used, but their efficiency and side effects raise questions. Objective: this clinical trial aimed to assess whether the bleaching mouthwash, containing 1.5% hydrogen peroxide, has a bleaching action and whether there are any side effects in the oral cavity. Methods: 10 volunteers were selected, with a mean age of 21.5 years, who underwent tooth color evaluation with the aid of a spectrometer in 3 moments: initial; with 15 and 30 days of using the washes. The evaluation of side effects was performed from the collection of stimulated saliva in 4 moments: before and after the first use of the product, at 15 and 30 days, and laboratory analyzes were carried out: salivary flow; pH; the number of Streptococcus mutans and Lactobacillus. Normal distribution was verified with Shapiro-Wilk test, comparisons of color were performed with t-test, comparisons of the microorganisms were performed with repeated measures ANOVA and Tukey tests. Results: the analysis did not show any significant changes in any of the investigated times. There were no significant changes in the salivary flow, pH and Lactobacillus. The number of Streptococcus mutans, was noted a significant increase when comparing the values after the first use and with 30 days. Conclusion: the mouthwash containing 1.5% hydrogen peroxide was not shown any significant alterations in the color teeth. There were not significant collateral effects on the cariogenic activity according to the tests and periods evaluated.

Evaluation of the botulinum toxin effects in the correction of gummy smile 32 weeks after application / Avaliação dos efeitos da toxina botulínica na correção do sorriso gengival 32 semanas pós-aplicação

INTRODUCTION: The use of botulinum toxin type A (BTX-A) to correct gummy smile has become popular in recent years. OBJECTIVE: To evaluate the effects of BTX-A application in the correction of gummy smile 2 and 32 weeks after application. METHODS: The sample comprised 35 patients (30 female, 5 male) at a mean age of 25.51 years (±5.59) with gummy smile due to muscular hyperfunction. In each patient, 2U of botulinum toxin was applied in the levator labii superioris alaeque nasi, 2 mm from the nasolabial fold. Photographs of spontaneous smiles were taken at 3 stages: before, 2 and 32 weeks after BTX application. Measurements of the gingival display were performed with the Radioface Studio 2 Software, and the calibration used the actual size of the right maxillary central incisor. Comparison of the three stages evaluated was performed with repeated measures ANOVA and Tukey tests. RESULTS: Gingival display decreased significantly 2 weeks after BTX-A application and increased after 32 weeks but did not return to the initial value. CONCLUSION: There was a significant improvement in gummy smile 2 weeks after botulinum toxin application, and a significant relapse in the gingival display after 32 weeks, however not returning to baseline values.

INTRODUÇÃO: A toxina botulínica tipo A (BTX-A) tem se tornado popular na correção do sorriso gengival nos últimos anos. OBJETIVO: Avaliar os efeitos da aplicação de BTX-A na correção do sorriso gengival 2 e 32 semanas após a aplicação. MÉTODOS: A amostra compreendeu 35 pacientes (30 mulheres, 5 homens) com uma idade inicial média 25,51 anos (±5,59) portadores de sorriso gengival devido à hiperfunção muscular. Em cada paciente foi aplicado 2U de BTX-A no músculo elevador superior da asa do nariz, 2 mm a partir da dobra nasolabial. Foram feitas fotografias dos sorrisos espontâneos dos pacientes em 3 fases: antes, 2 e 32 semanas após a aplicação de BTX-A. As medidas da exposição gengival foram feitas com o Software Radioface Studio 2, e a calibração utilizou o tamanho real do incisive central superior direito. A comparação das 3 fases foi feita com ANOVA de medidas repetidas e teste de Tukey. RESULTADOS: A exposição gengival diminuiu significantemente 2 semanas após a aplicação e aumentou novamente após 32 semanas, mas não retornando aos valores iniciais. CONCLUSÃO: Houve uma melhora significante no sorriso gengival 2 semanas após a aplicação de toxina Botulínica, e uma recidiva significante após 32 semanas, mas não retornando aos valores iniciais.

Evaluation of the force generated by gradual deflection of orthodontic wires in conventional metallic, esthetic, and self-ligating brackets.

OBJECTIVE:: The purpose of this study was to evaluate the deflection forces of Nitinol orthodontic wires placed in different types of brackets: metallic, reinforced polycarbonate with metallic slots, sapphire, passive and active self-ligating, by assessing strength values variation according to gradual increase in wire diameter and deflection and comparing different combinations in the different deflections. MATERIAL AND METHODS:: Specimens were set in a clinical simulation model and evaluated in a Universal Testing Machine (INSTRON 3342), using the ISO 15841 protocol. Data were subjected to One-way ANOVA, followed by Tukey tests (p<0.05). RESULTS:: Self-ligating brackets presented the most similar behavior to each other. For conventional brackets there was no consistent behavior for any of the deflections studied. CONCLUSIONS:: Self-ligating brackets presented the most consistent and predictable results while conventional brackets, as esthetic brackets, showed very different patterns of forces. Self-ligating brackets showed higher strength in all deflections when compared with the others, in 0.020-inch wires.

Efficiency of two protocols for maxillary molar intrusion with mini-implants.

OBJECTIVE: The aim of this study was to compare the efficiency of two protocols for maxillary molar intrusion with two or three mini-implants. METHODS: Twenty five maxillary first molars extruded for loss of their antagonists in adult subjects were selected. The sample was divided into two groups, according to the intrusion protocol with two or three mini-implants. Group 1 consisted of 15 molars that were intruded by two mini-implants. Group 2 consisted of 10 molars intruded by three mini-implants. Changes with treatment were analyzed in lateral cephalograms at the beginning and at the end of intrusion of maxillary molars. RESULTS: Results showed that there was no difference in efficiency for the two intrusion protocols. It was concluded that extruded maxillary molars can be intruded with two or three mini-implants with similar efficiency.

The effect of simvastatin on relapse of tooth movement and bone mineral density in rats measured by a new method using microtomography.

PURPOSE: To evaluate the effect of simvastatin on relapse of tooth movement in rats using microtomography (micro CT), as well as the correlation of bone density with the orthodontic relapse. METHODS: Twenty-five adult male Wistar rats, divided into two groups, had stainless steel springs installed on left maxillary first molar. The molars were moved for 18 days, and after removing the springs, were applied by oral gavage, 5mg/kg of simvastatin in the experimental group for 20 days. Tooth relapse was assessed with a micro CT scanner, and the images chosen through the Data Viewer software 1.5.0.0 had their measurement guides made and checked by the software Image ProR plus 5.1, and compared by Mann-Whitney test. After rats were sacrificed, bone mineral density was evaluated by micro CT through the software CT Analyzer 1.13 and compared by independent T-test, as well as by Spearman correlation test. RESULTS: Relapse and bone mineral density (BMD) was lower in the experimental group than in the control group, however without a statistically significant difference. CONCLUSION: Simvastatin did not inhibit the relapse of tooth movement in rats, and there was no correlation between bone density and orthodontic relapse.

Association between Bolton discrepancy and Angle malocclusions.

This study aimed to assess and compare the overall and anterior ratios of tooth size discrepancies in all Angle malocclusion groups. The following null hypothesis (H0) was tested: no difference between tooth size discrepancies (overall and anterior) would be observed among Angle malocclusion groups. The sample comprised of 711 pre-orthodontic treatment study casts of Brazilian patients with a mean age of 17.42 years selected from private practices in Brazil. The casts were divided into 3 groups according to the type of malocclusion: Class I (n = 321), Class II (n = 324), and Class III patients (n = 66). The measurement of the greatest mesiodistal width of the teeth was performed using a centesimal precision digital caliper directly on the study casts, from the distal surface of the left first molar to the distal surface of the right first molar. The overall and anterior ratios between the maxillary and mandibular teeth were evaluated using Bolton's method. The following statistical tests were applied: chi-square, independent t-test, and one-way ANOVA. Results showed that all Angle malocclusions groups exhibited a ratio compatible with those recommended by Bolton. With respect to the overall and anterior ratios among the malocclusion groups, no statistically significant differences were found. The null hypothesis was accepted because the results showed no differences in the overall and anterior ratios of tooth size discrepancies among different Angle malocclusion groups.

Transition temperature range of thermally activated nickel-titanium archwires.

OBJECTIVES: The shape memory resulting from the superelasticity and thermoelastic effect is the main characteristic of thermally activated NiTi archwires and is closely related to the transition temperature range (TTR). The aim of this study was to evaluate the TTR of thermally activated NiTi archwires commercially available. MATERIAL AND METHODS: Seven different brands of 0.019" x 0.025" thermally activated nickel-titanium archwires were tested as received by differential scanning calorimetry (DSC) over the temperature range from -100 °C to 150 °C at 10 °C/min. RESULTS: All thermally activated NiTi archwires analyzed presented stage transformation during thermal scanning with final austenitic temperature (Af) ranging from 20.39 °C to 45.42 °C. Three brands of NiTi archwires presented Af close to the room temperature and, this way, do not present properties of shape memory and pseudoelasticity that are desirable in clinical applications. CONCLUSIONS: The thermally activated NiTi archwires present great variability in the TTR and the elastic parameters of each NiTi archwire should be provided by the manufacturers, to allow achievement of the best clinical performance possible.

Postretention stability after orthodontic closure of maxillary interincisor diastemas.

UNLABELLED: Anterior spaces may interfere with smile attractiveness and compromise dentofacial harmony. They are among the most frequent reasons why patients seek orthodontic treatment. However, midline diastema is commonly cited as a malocclusion with high relapse incidence by orthodontists. OBJECTIVES: This study aimed to evaluate the stability of maxillary interincisor diastemas closure and the association of their relapse and interincisor width, overjet, overbite and root parallelism. MATERIAL AND METHODS: Sample comprised 30 patients with at least a pretreatment midline diastema of 0.5 mm or greater after eruption of the maxillary permanent canines. Dental casts and panoramic radiographs were taken at pretreatment, posttreatment and postretention. RESULTS: Before treatment, midline diastema width was 1.52 mm (SD=0.88) and right and left lateral diastema widths were 0.55 mm (SD=0.56) and 0.57 mm (SD=0.53), respectively. According to repeated measures analysis of variance, only midline diastema demonstrated significant relapse. In the overall sample the average relapse of midline diastema was 0.49 mm (SD=0.66), whilst the unstable patients showed a mean space reopening of 0.78 mm (SD=0.66). Diastema closure in the area between central and lateral incisors showed great stability. Multivariate correlation tests showed that only initial diastema width (ß=0.60) and relapse of overjet (ß=0.39) presented association with relapse of midline diastema. CONCLUSIONS: Midline diastema relapse was statistically significant and occurred in 60% of the sample, while lateral diastemas closure remained stable after treatment. Only initial diastema width and overjet relapse showed association with relapse of midline diastema. There was no association between relapse of interincisor diastema and root parallelism.

Stability of Class II treatment with the Bionator followed by fixed appliances.

OBJECTIVE: This prospective study assessed the stability of Class II treatment with the Bionator, followed by fixed appliances, 10 years after treatment. MATERIAL AND METHODS: The experimental group comprised 23 patients of both sexes (10 boys, 13 girls) at a mean initial age of 11.74 years (late mixed or early permanent dentitions), treated for a mean period of 3.55 years who were evaluated at three stages: initial (T1), final (T2) and long-term posttreatment (T3). A total of 69 lateral cephalograms were evaluated and 69 dental casts were measured using the PAR index. The difference between initial and final PAR indexes, the percentage of occlusal improvement obtained with therapy and the percentage of relapse were calculated, using the PAR index. The variables were compared by repeated measures analysis of variance (ANOVA) followed by Tukey tests. RESULTS: The significant improvement in apical base relationship, the palatal inclination of the maxillary incisors and the labial inclination of the mandibular incisors, and the significant improvement in molar relationship and reduction of overjet and overbite, obtained with treatment, remained stable in the long-term posttreatment period. There was also significant improvement in the occlusal relationships which remained stable in the long-term posttreatment period. The percentage of occlusal improvement obtained was of 81.78% and the percentage of relapse was of 4.90%. CONCLUSIONS: Treatment of Class II division 1 malocclusions with the Bionator associated with fixed appliances showed to be stable in the long-term posttreatment period.

Comparison of deflection forces of esthetic archwires combined with ceramic brackets

Abstract Coated archwires and ceramic brackets have been developed to improve facial esthetics during orthodontic treatment. However, their mechanical behavior has been shown to be different from metallic archwires and brackets. Therefore, the aim of this study was to compare the deflection forces in coated nickel-titanium (NiTi) and esthetic archwires combined with ceramic brackets. Material and Methods Non-coated NiTi (NC), rhodium coated NiTi (RC), teflon coated NiTi (TC), epoxy coated NiTi (EC), fiber-reinforced polymer (FRP), and the three different conventional brackets metal-insert polycrystalline ceramic (MI-PC), polycrystalline ceramic (PC) and monocrystalline ceramic (MC) were used. The specimens were set up on a clinical simulation device and evaluated in a Universal Testing Machine (Instron). An acrylic device, representative of the right maxillary central incisor was buccolingually activated and the unloading forces generated were recorded at 3, 2, 1 and 0.5 mm. The speed of the testing machine was 2 mm/min. ANOVA and Tukey tests were used to compare the different archwires and brackets. Results The brackets presented the following decreasing force ranking: monocrystalline, polycrystalline and polycrystalline metal-insert. The decreasing force ranking of the archwires was: rhodium coated NiTi (RC), non-coated NiTi (NC), teflon coated NiTi (TC), epoxy coated NiTi (EC) and fiber-reinforced polymer (FRP). At 3 mm of unloading the FRP archwire had a plastic deformation and produced an extremely low force in 2; 1 and 0.5 mm of unloading. Conclusion Combinations of the evaluated archwires and brackets will produce a force ranking proportional to the combination of their individual force rankings.

Evaluation of the force generated by gradual deflection of orthodontic wires in conventional metallic, esthetic, and self-ligating brackets

ABSTRACT Objective: The purpose of this study was to evaluate the deflection forces of Nitinol orthodontic wires placed in different types of brackets: metallic, reinforced polycarbonate with metallic slots, sapphire, passive and active self-ligating, by assessing strength values variation according to gradual increase in wire diameter and deflection and comparing different combinations in the different deflections. Material and Methods: Specimens were set in a clinical simulation model and evaluated in a Universal Testing Machine (INSTRON 3342), using the ISO 15841 protocol. Data were subjected to One-way ANOVA, followed by Tukey tests (p<0.05). Results: Self-ligating brackets presented the most similar behavior to each other. For conventional brackets there was no consistent behavior for any of the deflections studied. Conclusions: Self-ligating brackets presented the most consistent and predictable results while conventional brackets, as esthetic brackets, showed very different patterns of forces. Self-ligating brackets showed higher strength in all deflections when compared with the others, in 0.020-inch wires.