The role of environmental gradients and microclimates in structuring communities and functional groups of lizards in a rainforest-savanna transition area.

Environmental heterogeneity poses a significant influence on the functional characteristics of species and communities at local scales. Environmental transition zones, such as at the savanna-forest borders, can act as regions of ecological tension when subjected to sharp variations in the microclimate. For ectothermic organisms, such as lizards, environmental temperatures directly influence physiological capabilities, and some species use different thermoregulation strategies that produce varied responses to local climatic conditions, which in turn affect species occurrence and community dynamics. In the context of global warming, these various strategies confer different types of vulnerability as well as risks of extinction. To assess the vulnerability of a species and understand the relationships between environmental variations, thermal tolerance of a species and community structure, lizard communities in forest-savanna transition areas of two national parks in the southwestern Amazon were sampled and their thermal functional traits were characterized. Then, we investigated how community structure and functional thermal variation were shaped by two environmental predictors (i.e., microclimates estimated locally and vegetation structure estimated from remote sensing). It was found that the community structure was more strongly predicted by the canopy surface reflectance values obtained via remote sensing than by microclimate variables. Environmental temperatures were not the most important factor affecting the occurrence of species, and the variations in ecothermal traits demonstrated a pattern within the taxonomic hierarchy at the family level. This pattern may indicate a tendency for evolutionary history to indirectly influence these functional features. Considering the estimates of the thermal tolerance range and warming tolerance, thermoconformer lizards are likely to be more vulnerable and at greater risk of extinction due to global warming than thermoregulators. The latter, more associated with open environments, seem to take advantage of their lower vulnerability and occur in both habitat types across the transition, potentially out-competing and further increasing the risk of extinction and vulnerability of forest-adapted thermoconformer lizards in these transitional areas.

Tendência temporal dos homicídios de mulheres nos estados da região Sudeste do Brasil, de 2007 a 2019 / Timeline trend of homicides of women in the states of the Southeast region of Brazil between 2007 and 2019

Resumo O objetivo deste artigo é analisar a tendência temporal de homicídios de mulheres no período de 2007 a 2019, na região Sudeste do Brasil. Trata-se de um estudo ecológico misto dos homicídios em mulheres, de 2007 a 2019, considerando-se como unidade de análise os anos do estudo e os estados que compõem a região Sudeste. Os dados foram obtidos via Sistema de Informação sobre Mortalidade (SIM) e tabulados pelo TABNET. Empregou-se o modelo de regressão de Prais-Winsten para verificação de tendência de homicídios. Foram registrados 18.415 homicídios de mulheres entre 2007 e 2019 na região Sudeste. Cerca de 9.691 (53,64%) eram mulheres pretas, 5.118 (27,80%) com escolaridade de 4 a 7 anos e 10.841 (58,87%) solteiras. As variações percentuais anuais foram: São Paulo -3,73; IC95% [-6,09; -1,32], Espírito Santo -5,67; IC95% [-7,11; -4,21], Rio de Janeiro -3,86; IC95% [-9,54; 2,17] e Minas Gerais -2,11; IC95% [-4,87; 0,73]. São Paulo e Espírito Santo apresentaram taxas de homicídios de mulheres decrescentes, enquanto Minas Gerais e Rio de Janeiro taxas estacionárias. As maiores taxas de homicídio no período ocorreram em mulheres solteiras, pretas e com escolaridade de quatro a sete anos. Faz-se necessária a construção de redes sociais que viabilizem a proteção integral das mulheres.

Abstract The scope of this article is to analyze the timeline trend of homicides of women between 2007 and 2019, in the Southeast region of Brazil. It is a mixed ecological study of homicides in women, from 2007 to 2019, considering the years of the study and the states that that make up the Southeast region as the unit of analysis. The data were obtained via the Mortality Information System (SIM) and tabulated by TABNET. The Prais-Winten regression model was used to verify the homicide trend. There were 18,415 homicides of women between 2007 and 2019 in the Southeast region. A total of 9,691 (53.64%) were black women, 5,118 (27.8%) had 4 to 7 years of schooling and 10,841 (58.87%) were single. The annual percentage variations were: São Paulo -3.73 ; 95%CI [-6.09; -1.32], Espírito Santo -5.67 ; 95%CI [-7.11;-4.21], Rio de Janeiro -3.86; 95%CI [-9.54; 2.17] and Minas Gerais -2.11 ; 95%CI [-4.87; 0.73]. São Paulo and Espírito Santo presented decreasing homicide rates for women, while Minas Gerais and Rio de Janeiro showed stationary rates. The highest homicide rates in the period were single women, black women and women with 4 to 7 years of schooling. It is necessary to build social networks that ensure the full protection of women.

[Timeline trend of homicides of women in the states of the Southeast region of Brazil between 2007 and 2019]. / Tendência temporal dos homicídios de mulheres nos estados da região Sudeste do Brasil, de 2007 a 2019.

The scope of this article is to analyze the timeline trend of homicides of women between 2007 and 2019, in the Southeast region of Brazil. It is a mixed ecological study of homicides in women, from 2007 to 2019, considering the years of the study and the states that that make up the Southeast region as the unit of analysis. The data were obtained via the Mortality Information System (SIM) and tabulated by TABNET. The Prais-Winten regression model was used to verify the homicide trend. There were 18,415 homicides of women between 2007 and 2019 in the Southeast region. A total of 9,691 (53.64%) were black women, 5,118 (27.8%) had 4 to 7 years of schooling and 10,841 (58.87%) were single. The annual percentage variations were: São Paulo -3.73 ; 95%CI [-6.09; -1.32], Espírito Santo -5.67 ; 95%CI [-7.11;-4.21], Rio de Janeiro -3.86; 95%CI [-9.54; 2.17] and Minas Gerais -2.11 ; 95%CI [-4.87; 0.73]. São Paulo and Espírito Santo presented decreasing homicide rates for women, while Minas Gerais and Rio de Janeiro showed stationary rates. The highest homicide rates in the period were single women, black women and women with 4 to 7 years of schooling. It is necessary to build social networks that ensure the full protection of women.

O objetivo deste artigo é analisar a tendência temporal de homicídios de mulheres no período de 2007 a 2019, na região Sudeste do Brasil. Trata-se de um estudo ecológico misto dos homicídios em mulheres, de 2007 a 2019, considerando-se como unidade de análise os anos do estudo e os estados que compõem a região Sudeste. Os dados foram obtidos via Sistema de Informação sobre Mortalidade (SIM) e tabulados pelo TABNET. Empregou-se o modelo de regressão de Prais-Winsten para verificação de tendência de homicídios. Foram registrados 18.415 homicídios de mulheres entre 2007 e 2019 na região Sudeste. Cerca de 9.691 (53,64%) eram mulheres pretas, 5.118 (27,80%) com escolaridade de 4 a 7 anos e 10.841 (58,87%) solteiras. As variações percentuais anuais foram: São Paulo -3,73; IC95% [-6,09; -1,32], Espírito Santo -5,67; IC95% [-7,11; -4,21], Rio de Janeiro -3,86; IC95% [-9,54; 2,17] e Minas Gerais -2,11; IC95% [-4,87; 0,73]. São Paulo e Espírito Santo apresentaram taxas de homicídios de mulheres decrescentes, enquanto Minas Gerais e Rio de Janeiro taxas estacionárias. As maiores taxas de homicídio no período ocorreram em mulheres solteiras, pretas e com escolaridade de quatro a sete anos. Faz-se necessária a construção de redes sociais que viabilizem a proteção integral das mulheres.

Weight-loss and surface roughness of enamel after microabrasion procedure with different agents / Perda de peso e rugosidade da superfície do esmalte após procedimento de microabrasão com diferentes agentes

Introduction: Enamel microabrasion is achieved by abrasion of the enamel surface and it is a quick, practical and efficient procedure. Objective It was assessed the weight loss and surface aspect of enamel after microabrasion procedures with commercial and mixtures made in-office. Material and method Eighty bovine incisors were divided into four groups (n=10): OpalustreTM (6.6% HCl + silicon carbide); Whiteness RMTM (6% HCl + silicon carbide); 37% H3PO4 + pumice and 10% HCl + pumice. Treatment was performed by 15 applications of 10s duration. The enamel weight loss was determined by the difference in weight before and after the microabrasion. The surfaces were analyzed by a surface roughness equipment and scanning electron microscopy. Data were submitted to paired-T test, one-way ANOVA and Tukey tests (α=0.05). Result It was observed significantly weight loss for all groups. The difference in weight loss ranged from 0.037±0.012 for group 37% H3PO4 and from 0.054±0.009 for group 6,6% HCl. There was a significant increase in surface roughness for all groups and 10% HCl group showed the lower results (0.65±0.09). It was observed different patterns of enamel morphology by SEM images. Conclusion The in-office mixtures resulted in the lowest enamel structure loss (37% H3PO4) and the lowest surface roughness (10% HCl).

Introdução: A microabrasão do esmalte é realizada através da abrasão da superfície do mesmo, apresentando-se como um procedimento rápido, prático e eficiente. Objetivo Avaliar a perda de peso e o aspecto superficial do esmalte após procedimentos de microabrasão com agentes comerciais e não comerciais. Material e método Oitenta incisivos bovinos foram divididos em quatro grupos (n = 10): OpalustreTM (6,6% HCl + carboneto de silício); Whiteness RMTM (6% HCl + carboneto de silício); 37% H3PO4 + pedra-pomes e 10% HCl + pedra-pomes. O tratamento foi realizado em 15 aplicações de 10s de duração. A perda de peso do esmalte foi determinada pela diferença de peso antes e depois da microabrasão. As superfícies foram analisadas por equipamento de rugosidade superficial e microscopia eletrônica de varredura. Os dados foram submetidos ao teste T-pareado, ANOVA one-way e teste de Tukey (α = 0,05). Resultado Foi observada perda de peso significativa para todos os grupos, a diferença na perda de peso variou de -0,037±0,012 para o grupo 37% H3PO4 a -0.054±0.009 para o grupo 6.6% HCl. Houve um aumento significativo na rugosidade da superfície para todos os grupos e o grupo 10%HCl apresentou os resultados mais baixos (0,65±0,09). Foram observados diferentes padrões de morfologia do esmalte por meio de imagens MEV. Conclusão Os agentes não comerciais resultaram na menor perda de estrutura do esmalte (37% H3PO4) e na rugosidade superficial (10% HCl).

Effect of hydrochloric acid commercial presentation for microabrasion technique on loss of enamel structure and surface / Efeito da apresentação comercial de ácido clorídrico para técnica de microabrasão na perda de estrutura e superfície do esmalte

Introdução: A técnica de microabrasão pode ser realizada através de pasta pronta para uso, disponível comercialmente, ou o profissional pode manipulá-la no consultório. Objetivo: Verificar o efeito da apresentação comercial do ácido clorídrico a 10% na manipulação de pasta para microabrasão sobre a superfície do esmalte. Metodologia: Foram selecionados incisivos bovinos e divididos em dois grupos, de acordo com a apresentação comercial do ácido clorídrico (líquido ou em gel). O tratamento foi realizado através de dez aplicações com 10s de duração cada, intercaladas por lavagem de 10s. Vinte incisivos (n=10) foram utilizados para se determinar a perda de estrutura do esmalte. Cada amostra foi pesada, em balança analítica, antes e após submissão à microabrasão. Outras 20 amostras (n=10) foram utilizadas para determinação da rugosidade superficial média (Ra) utilizando-se um rugosímetro. Três amostras de cada grupo do experimento anterior foram selecionadas, aleatoriamente, e outras três amostras adicionais foram preparadas como controle (baseline) para análise em MEV. Resultados: Verificou-se diferença estatística significativa entre a massa final e a inicial e rugosidade superficial das amostras, independente da apresentação comercial do ácido. Nas imagens de MEV observou-se presença de superfície regular para o grupo controle (baseline). Nas demais imagens verificou-se superfície com considerável irregularidade e dissolução discreta do esmalte. Conclusões: O tratamento realizado causou perda significativa de estrutura e aumentou a rugosidade superficial dos espécimes, independente da apresentação comercial do ácido e sem apresentar diferença entre os grupos ao final. A apresentação comercial do ácido não parece ser um fator a interferir no tratamento. (AU)

Introduction: The microabrasion technique can be performed using a commercially available paste, or the dentist can prepare it in his office. Objective: To verify the effect of hydrochloric acid commercial presentation in the handling of microabrasion paste on the enamel surface. Methodology: Bovine incisors were divided into two groups, according to the commercial presentation of 10% hydrochloric acid (liquid or gel). The treatment was carried out through ten applications of 10 s duration each, intercalated with a 10s wash. Twenty teeth (n=10) were used to determine the loss of enamel structure. Each sample was weighed on an analytical balance before and after submission to microabrasion. Another 20 teeth (n=10) were used to determine the average surface roughness (Ra) using a rugosimeter. Three samples from each group of the previous experiment were selected, randomly, and another three additional samples were repared as a control (baseline) for SEM analysis. Results: There was a statistically significant difference between the final and initial mass and the surface roughness of the samples, regardless of the acid commercial presentation. In the SEM images, a regular surface was observed for the control group (baseline). In the other images, there was a surface with considerable irregularity and a slight dissolution of the enamel. Conclusions: The treatment carried out. (AU)

Second molar intrusion: Continuous arch or loop mechanics?

INTRODUCTION: Our aim was to compare the load systems produced by rectangular loops and continuous arch mechanics on intrusion of a maxillary second molar. METHODS: An orthodontic appliance was passively bonded from second molar to second molar on a patient's model fixed to an orthodontic force tester. The second molars were extruded by 3 mm, and 2 mechanics systems were compared: beta-titanium rectangular loops and super-elastic nickel-titanium continuous arch. Vertical (Fz) and mesial (Fy) forces, and tipping moments around the buccal axis (Mx) at the tubes were collected at every 0.5 mm of deactivation. Repeated measures analysis of variance was used to detect differences between mechanics. The net Mx was also estimated at the center of resistance of each molar. RESULTS: Significant differences were found between the mechanics at the tubes, except for the Mx in the first molar, and more importantly, at the centers of resistance of the molars: Fz forces were greater in the continuous arch than in the rectangular loops, which, on the other hand, produced lower Fy forces than the continuous arch. In the second molar, net Mx was low initially and changed with deactivation. In the continuous arch, net Mx decreased from -3.6 N.mm of mesial crown tipping to clinically insignificant levels after 2 mm of deactivation. In the first molar, net Mx was lower on the rectangular loop than on the continuous arch during the first 2 mm of deactivation and became similar in the last millimeter of deactivation. Additionally, the net Mx decreased with deactivation with both mechanics. CONCLUSIONS: Both mechanics can intrude the second molars. Although the rectangular loop produced less tipping in large deflections, the continuous arch was a better approach when less intrusion was required.

Effects of reducing light-curing time of a high-power LED device on shear bond strength of brackets.

PURPOSE: To assess the effects of reducing the curing time of a high-power light-emitting diode (LED) unit (Valo, Ultradent, South Jordan, UT, USA) on shear bond strength (SBS) of metal brackets and on the amount of adhesive remnant of two orthodontic composites. METHODS: Eighty human premolars were divided into four groups (G1-4) according to curing time and composite: G1 (Transbond XT, 6 s), G2 (Opal Bond MV, 6 s), G3 (Transbond XT, 3 s), and G4 (Opal Bond MV, 3 s). Twenty-four hours after bonding, brackets were subject to a SBS test performed with a universal testing machine. Enamel surface was analyzed by SEM and the amount of adhesive remnant was assessed by the Image J software area calculation tool. Two-way analysis of variance was used for statistical analysis of SBS data, while Friedman and Mann-Whitney post hoc tests were used to analyze data on the amount of adhesive remnant. RESULTS: Time and composite significantly affected SBS (p < 0.001). The 6 s curing showed a higher SBS value (21.56 MPa) in comparison to 3 s curing (15.79 MPa). Transbond XT composite showed a significantly higher SBS value (21.06 MPa) compared to Opal Bond MV (16.29 MPa). After the SBS test, Opal Bond MV showed a significantly greater amount of composite adhered to enamel (p < 0.001). CONCLUSION: Reducing exposure time from 6 to 3 s significantly decreased mean values of SBS, even with the use of a high-power LED unit. Reduction in time did not affect the amount of adhesive remnant.

Welding strength of NiTi wires.

OBJECTIVE: To identify the appropriate power level for electric welding of three commercial brands of nickel-titanium (NiTi) wires. METHODS: Ninety pairs of 0.018-in and 0.017 × 0.025-in NiTi wires were divided into three groups according to their manufacturers - GI (Orthometric, Marília, Brazil), GII (3M OralCare, St. Paul, CA) and GIII (GAC,York, PA) - and welded by electrical resistance. Each group was divided into subgroups of 5 pairs of wires, in which welding was done with different power levels. In GI and GII, power levels of 2.5, 3, 3.5, 4, 4.5 and 5 were used, while in GIII 2.5, 3, 3.5 and 4 were used (each unit of power of the welding machine representing 500W). The pairs of welded wires underwent a tensile strength test on an universal testing machine until rupture and the maximum forces were recorded. Analysis of variance (ANOVA) and post-hoc tests were conducted to determine which subgroup within each brand group had the greatest resistance to rupture. RESULTS: The 2.5 power exhibited the lowest resistance to rupture in all groups (43.75N for GI, 28.41N for GII and 47.57N for GIII) while the 4.0 power provided the highest resistance in GI and GII (97.90N and 99.61N, respectively), while in GIII (79.28N) the highest resistance was achieved with a 3.5 power welding. CONCLUSIONS: The most appropriate power for welding varied for each brand, being 4.0 for Orthometric and 3M, and 3.5 for GAC NiTi wires.

Evaluation of the load system produced by a single intrusion bend in a maxillary lateral incisor bracket with different alloys.

OBJECTIVES: To evaluate if a 0.5-mm vertical bend applied on an incisor bracket produces movements in other planes and if different wires influence these effects. MATERIALS AND METHODS: An acrylic model of a treated patient with brackets passively bonded was attached to an Orthodontic Force Tester, and a load cell was attached to the left lateral incisor. Thirty 0.019 × 0.025-inch archwires were divided into three groups according to their alloy: SS (stainless steel), B-Ti (beta-titanium), and MF (beta-titanium wire coated with nickel-titanium). Step-bends of 0.5 mm high were placed on the lateral incisor bracket using a universal plier, and the forces and moments in three dimensions were statistically analyzed by analysis of variance and Tukey post hoc test. RESULTS: SS produced a larger force (3.4 N) than the B-Ti (1.41 N) and the MF (0.53 N; P < .001). Lingual forces were produced by the SS (0.82 N) and B-Ti (0.31 N) groups, while in the MF group, the force was insignificant. SS produced a mesial force of 0.24 N, while the B-Ti force was insignificant and MF produced 0.09 N. Groups produced different crown-distal tipping moments (SS = 31.48 N-mm, B-Ti = 11.7 N-mm, and MF = 4.55 N-mm) and different crown-buccal tipping moments. SS produced larger moments (3.63 N-mm) than B-Ti (1.02 N-mm) and MF (0.36 N-mm) wires. A mesial-out rotational moment was observed in all groups (SS = 7.17 N-mm, B-Ti = 3.46 N-mm, and MF = 0.86 N-mm). CONCLUSIONS: A 0.5-mm intrusion bend produced lingual and mesial side effects. In addition to the distal and buccal crown-tipping moments, there was a mesial-out moment. Compared with SS, B-Ti and MF wires produced lower forces. These more flexible wires showed side effects with lesser intensity.

Continuous arch and rectangular loops for the correction of consistent and inconsistent load systems in extruded and tipped maxillary second molars.

INTRODUCTION: The aim of this research was to compare the load systems produced by rectangular loops and continuous arches for the correction of extruded second molars with a mesial inclination (inconsistent system) and a distal inclination (consistent system). METHODS: The maxillary first molar of an acrylic model of a patient, with passive brackets and tubes bonded, was connected to a 3-dimensional load cell of an orthodontic force tester, and the second molar was replaced by its respective tube bonded to a second load cell. The second molar tube was moved 2.5 mm occlusally and tipped 20° mesially and distally, creating an inconsistent force system and a consistent force system. For each situation, ten 0.017 × 0.025-in beta-titanium, 8 × 10-mm rectangular loops were compared with 10 0.014-in nickel-titanium continuous arches. The vertical forces-F(z)-and tipping moments-M(x)-were compared using 4 t tests, at 5%. RESULTS: In the inconsistent group, the rectangular loop produced a larger M(x) in both molars: 2.11 N.mm in the second molar compared with the -0.15 N.mm of the continuous arches. On the first molar, the rectangular loops produced -5.58 N.mm against -2.08 N.mm produced by the continuous arches. The F(z) values produced at the second molar with each system were similar, whereas on the first molar they were different; the rectangular loops produced 0.41N, and continuous arches produced 0.53N. In the consistent group, the rectangular loops produced smaller M(x) values at the second molar (-3.06 N.mm) than did the continuous arch (-4.25 N.mm) (P = 0.01), as well as a smaller F(z) value (-0.52 vs -0.92 N, respectively). At the first molar, the rectangular loops produced smaller M(x) values (-2.32 N.mm) than did the continuous arch (-4.18 N.mm), as well as a smaller F(z) value (0.59 vs 1.10 N). CONCLUSIONS: In the inconsistent group, only the rectangular loop produced a system of force that could correct the second molar. In the consistent system, both group mechanics produced a system of force compatible with the correction of the second molar, but the continuous wire produced larger moments. Both groups showed a tendency for mesial crown tipping of the first molar.

Stability of beta-titanium T-loop springs preactivated by gradual curvature

ABSTRACT Objective: Evaluate changes in the force system of T-Loop Springs (TLS) preactivated by curvature, due to stress relaxation. Methods: Ninety TLSs measuring 6 x 10 mm, produced out with 0.017 x 0.025-in TMA® wire and preactived by gradual curvature, were randomly distributed into nine groups according to time point of evaluation. Group 1 was tested immediately after spring preactivation and stress relief, by trial activation. The other eight groups were tested after 24, 48 and 72 hours, 1, 2, 4, 8 and 12 weeks, respectively. Using a moment transducer coupled to a digital extensometer indicator adapted to a universal testing machine, the amount of horizontal force, moment and moment-to-force ratios were recorded at every 0.5 mm of deactivation from 5 mm of the initial activation, in an interbracket distance of 23 mm. Results: The horizontal forces decreased gradually among the groups (p< 0.001) and the moments showed a significant and slow decrease over time among the groups (p< 0.001). All groups produced similar M/F ratios (p= 0.532), with no influence of time. Conclusions: The TLSs preactivated by curvature suffered a gradual deformation over time, which affected the force system, specifically the moments, which affected the horizontal forces produced.

RESUMO Objetivo: avaliar as mudanças no sistema de forças das molas T pré-ativadas por curvatura, devido ao alívio de tensão estrutural. Métodos: noventa molas em forma de "T", medindo 6 mm x 10 mm, confeccionadas com fio de beta-titânio TMA® de 0,017" x 0,025" e pré-ativadas por curvatura gradual, foram distribuídas aleatoriamente em nove grupos, de acordo com o momento de avaliação. O Grupo 1 foi testado imediatamente após a pré-ativação da mola e liberação do estresse, por meio de simulação da ativação. Os outros oito grupos foram divididos conforme o intervalo de tempo testado: após 24, 48 e 72 horas; 1, 2, 4, 8 e 12 semanas. Usando um transdutor de momentos acoplado a um indicador digital para extensometria e adaptado a uma máquina universal de ensaios, as magnitudes da força horizontal, do momento e da proporção momento/força (M/F) foram registradas a cada 0,5 mm de desativação a partir da ativação inicial de 5 mm, utilizando-se uma distância interbraquetes de 23 mm. Resultados: as forças horizontais reduziram-se gradualmente nos grupos (p< 0,001) e o momento apresentou uma queda lenta e significativa ao longo do tempo (p< 0,001). Todos os grupos tiveram proporções M/F semelhantes (p= 0,532), não influenciadas pelo período de tempo. Conclusões: as molas pré-ativadas por curvatura gradual sofreram deformação progressiva ao longo do tempo, o que afetou o sistema de forças - especificamente o momento -, alterando as forças horizontais produzidas.

Deformation of nickel-titanium closed coil springs: an in vitro study.

OBJECTIVE: The aim of this paper was to determine the amount of deformation in four commercial brands of nickel-titanium closed springs. METHODS: A total of 130 springs were divided into 13 subgroups, according to their features and manufacturers (Morelli, Orthometric, Ormco and GAC) and activated from 100% to 1000% of the effective length of the nickel-titanium portion present at the spring, at 37 °C. Deactivation data were plotted and deformation was found graphically. The values were compared by analysis of variance and Tukey's post-hoc test. RESULTS: Springs manufactured by Morelli had the same amount of deformation when they were activated up to 700% of Y activation; springs by Orthometric had the same amount of deformation up to 600-700% of Y; springs by Ormco had the same amount of deformation up to 700-800% of Y; and finally, the majority of springs by GAC had similar deformation up to 800%-1000% of activation. All springs tested could be activated up to 700% without rupture. CONCLUSIONS: Most subgroups were similarly deformed up to 700% of activation, without rupture of springs. Subgroups 4B, 4C, 4D and 4E showed the same amount of deformation up to 1000% of activation without any rupture at all.

Assessing adhesive remnant removal and enamel damage with ultraviolet light: An in-vitro study.

INTRODUCTION: Our objective was to assess the amounts of adhesive remnant and enamel damage when removing composite under conventional lighting and ultraviolet (UV) light. METHODS: Thirty-eight premolars were divided into 2 groups according to the lighting used for adhesive removal. A multifluted tungsten-carbide bur at low speed was used for this process in both groups. The UV group received conventional lighting associated with UV light, and the conventional group received conventional lighting only. The amounts of adhesive remnant were calculated using images of the teeth taken under UV light with software. Scanning electron microscopy images of epoxy adhesive replicas of the teeth made before bonding and after adhesive removal were graded according to the enamel damage index (EDI), and the difference between the final and initial EDI scores was used for assessment of the enamel damage. To detect differences between the groups, the Mann-Whitney test was used to analyze the data from the adhesive remnant index and the EDI. RESULTS: The conventional group had more adhesive left on the enamel (P <0.001) than did the UV group. There was no difference between groups for the EDI (P = 0.729). CONCLUSIONS: UV lighting allows significantly more adhesive removal without increasing the damage caused to the enamel.

Deformation of nickel-titanium closed coil springs: an in vitro study

ABSTRACT Objective: The aim of this paper was to determine the amount of deformation in four commercial brands of nickel-titanium closed springs. Methods: A total of 130 springs were divided into 13 subgroups, according to their features and manufacturers (Morelli, Orthometric, Ormco and GAC) and activated from 100% to 1000% of the effective length of the nickel-titanium portion present at the spring, at 37 °C. Deactivation data were plotted and deformation was found graphically. The values were compared by analysis of variance and Tukey's post-hoc test. Results: Springs manufactured by Morelli had the same amount of deformation when they were activated up to 700% of Y activation; springs by Orthometric had the same amount of deformation up to 600-700% of Y; springs by Ormco had the same amount of deformation up to 700-800% of Y; and finally, the majority of springs by GAC had similar deformation up to 800%-1000% of activation. All springs tested could be activated up to 700% without rupture. Conclusions: Most subgroups were similarly deformed up to 700% of activation, without rupture of springs. Subgroups 4B, 4C, 4D and 4E showed the same amount of deformation up to 1000% of activation without any rupture at all.

RESUMO Objetivo: o objetivo desse trabalho foi determinar a deformação em molas fechadas de níquel-titânio de quatro marcas comerciais. Métodos: cento e trinta molas foram divididas em treze subgrupos, de acordo com suas características e fabricantes (Morelli, Orthometric, Ormco e GAC), com ativação entre 100% e 1.000% do comprimento efetivo de níquel-titânio presente na mola (Y), a 37 °C. Dados de desativação foram coletados e a deformação foi obtida de forma gráfica. Os valores foram comparados por meio de análise de variância e teste post-hoc de Tukey. Resultados: as molas da Morelli apresentaram a mesma quantidade de deformação considerando-se 700% de ativação de Y; as molas da Orthometric tiveram a mesma quantidade de deformação até 600-700% de Y; as molas da Ormco tiveram a mesma quantidade de deformação até 700-800% de Y; e, por fim, a maioria das molas da GAC apresentou deformação semelhante até 800-1.000% de ativação. Todas as molas testadas puderam ser ativadas até 700% sem ruptura. Conclusões: a maioria dos subgrupos se deformou de maneira semelhante até 700% de ativação, sem ruptura das molas. Os subgrupos 4B, 4C, 4D e 4E demonstraram a mesma quantidade de deformação até 1.000% de ativação, sem nenhuma ruptura.

Stability of beta-titanium T-loop springs preactivated by gradual curvature.

OBJECTIVE: Evaluate changes in the force system of T-Loop Springs (TLS) preactivated by curvature, due to stress relaxation. METHODS: Ninety TLSs measuring 6 x 10 mm, produced out with 0.017 x 0.025-in TMA® wire and preactived by gradual curvature, were randomly distributed into nine groups according to time point of evaluation. Group 1 was tested immediately after spring preactivation and stress relief, by trial activation. The other eight groups were tested after 24, 48 and 72 hours, 1, 2, 4, 8 and 12 weeks, respectively. Using a moment transducer coupled to a digital extensometer indicator adapted to a universal testing machine, the amount of horizontal force, moment and moment-to-force ratios were recorded at every 0.5 mm of deactivation from 5 mm of the initial activation, in an interbracket distance of 23 mm. RESULTS: The horizontal forces decreased gradually among the groups (p< 0.001) and the moments showed a significant and slow decrease over time among the groups (p< 0.001). All groups produced similar M/F ratios (p= 0.532), with no influence of time. CONCLUSIONS: The TLSs preactivated by curvature suffered a gradual deformation over time, which affected the force system, specifically the moments, which affected the horizontal forces produced.

Case Report of Posterior Crossbite: Description of an Effective Treatment Protocol.

Early treatment of functional unilateral posterior crossbite during the mixed dentition stage is extremely important, as it provides the correct positioning of osseous bases, teeth, and the temporomandibular joint when the stomatognathic system is in growth and development. This article reports on a 9-year-old patient who presented with functional unilateral posterior crossbite and was treated with a modified Hyrax expander. The case report highlights a simple, low-cost, effective treatment protocol. The malocclusion was corrected with 15 days of active use of the appliance, 5 months of use for retention purposes, and 5 years of post-treatment follow-up. The stability in the long-term treatment is highly dependent on early diagnosis by the clinician and the elimination of the etiological factor through use of the proper appliance.

Superelasticity and force plateau of nickel-titanium springs: an in vitro study.

OBJECTIVE: This paper analyzed whether nickel-titanium closed coil springs (NTCCS) have a different superelastic (SE) behavior according to activation and whether their force plateau corresponds to that informed by the manufacturer. METHODS: A total of 160 springs were divided into 16 subgroups according to their features and activated proportionally to the length of the extensible part (NiTi) of the spring (Y). The force values measured were analyzed to determine SE rates and force plateaus, which were mathematically calculated. These plateaus were compared to those informed by the manufacturer. Analysis of variance was accomplished followed by Tukey post-hoc test to detect and analyze differences between groups. RESULTS: All subgroups were SE at the activation of 400% of Y length, except for: subgroups 4B and 3A, which were SE at 300%; subgroups 4E and 4G, which were SE at 500%; and subgroup 3C, which was SE at 600%. Subgroup 3B did not show a SE behavior. Force plateaus depended on activation and, in some subgroups and some activations, were similar to the force informed. CONCLUSIONS: Most of the springs showed SE behavior at 400% of activation. Force plateaus are difficult to compare due to lack of information provided by manufacturers.

Superelasticity and force plateau of nickel-titanium springs: an in vitro study

abstract Objective: This paper analyzed whether nickel-titanium closed coil springs (NTCCS) have a different superelastic (SE) behavior according to activation and whether their force plateau corresponds to that informed by the manufacturer. Methods: A total of 160 springs were divided into 16 subgroups according to their features and activated proportionally to the length of the extensible part (NiTi) of the spring (Y). The force values measured were analyzed to determine SE rates and force plateaus, which were mathematically calculated. These plateaus were compared to those informed by the manufacturer. Analysis of variance was accomplished followed by Tukey post-hoc test to detect and analyze differences between groups. Results: All subgroups were SE at the activation of 400% of Y length, except for: subgroups 4B and 3A, which were SE at 300%; subgroups 4E and 4G, which were SE at 500%; and subgroup 3C, which was SE at 600%. Subgroup 3B did not show a SE behavior. Force plateaus depended on activation and, in some subgroups and some activations, were similar to the force informed. Conclusions: Most of the springs showed SE behavior at 400% of activation. Force plateaus are difficult to compare due to lack of information provided by manufacturers.

resumo Objetivo: o presente artigo analisou se as molas helicoidais fechadas de níquel-titânio apresentam superelasticidade (SE), de acordo com a ativação, e se o platô de força medido corresponde ao informado pelo fabricante. Material e Métodos: 160 molas foram divididas em 16 subgrupos, de acordo com suas características, e foram ativadas proporcionalmente ao comprimento da parte extensível (NiTi) da mola (Y). Os valores de força obtidos foram analisados para determinar as taxas de SE e os platôs de força, os quais foram calculados matematicamente - sendo esses platôs comparados aos informados pelos fabricantes. Uma análise de variância foi realizada, seguida do teste post-hoc de Tukey, para detectar e analisar as diferenças entre os grupos. Resultados: todos os subgrupos apresentaram SE em ativação de 400% do comprimento Y, com exceção dos subgrupos 4B e 3A (que apresentaram SE a 300%), dos subgrupos 4E e 4G (com SE a 500%) e do subgrupo 3C (que apresentou SE na ativação de 600%). O subgrupo 3B não apresentou comportamento superelástico. Os platôs de força dependeram da ativação e em alguns subgrupos, em determinadas ativações, foram semelhantes à força informada pelo fabricante. Conclusões: a maioria das molas apresentou comportamento superelástico na ativação de 400%. Os platôs de força são difíceis de ser comparados, devido à falta de informações por parte dos fabricantes.

Os alinhadores quase invisíveis são aparelhos que quase funcionam? / Do the almost invisible aligners almost work?

Os alinhadores quase invisíveis continuam atraindo muita atenção dos ortodontistas contemporâneos, e muitas publicações descrevem os passos para confeccionar alinhadores ou apresentam casos clínicos. O objetivo deste artigo foi buscar a fundamentação biomecânica de seu uso na literatura, e discutir a eficiência para os movimentos necessários para a correção das mais diversas más-oclusões. Seja qual for o aparelho utilizado, para que um movimento ocorra com previsibilidade, o controle de forças e momentos devem ser obtidos. O desenvolvimento dos alinhadores vem sendo reportado desde os anos 1940, e muitos recursos foram implementados com a utilização da tecnologia tridimensional de modelos virtuais para a manipulação dos movimentos desejados dos dentes. Pesquisas laboratoriais e clínicas foram discutidas para evidenciar as possibilidades mecânicas desses sistemas e avaliar se eles podem, de fato, ser usados para tratamentos ortodônticos ou meramente para alinhar dentes e realizar pequenos movimentos dentários...

The nearly invisible aligners continue to attract much attention from contemporary orthodontists. Many publications describe the steps for making aligners or present clinical cases. The purpose of this article is to search in literature the biomechanical basis of its use and discuss the efficiency of the movements required for the correction of various malocclusions. Whatever the apparatus used so that a movement occurs predictably, the control forces and moments must be obtained. The development of aligners has been reported since 40’s and many resources have been implemented using three dimensional virtual models technology for handling the desired tooth movement. Laboratory and clinical research were discussed to demonstrate the mechanical possibilities of these systems and assess whether they can in fact be used for orthodontic treatments or merely to align teeth and small tooth movements...

Nickel titanium T-loop wire dimensions for en masse retraction.

OBJECTIVE: To compare the force system produced by nickel-titanium T-loop springs made with wires of different dimensions. MATERIAL AND METHODS: Thirty compound T-loop springs were divided into three groups according to the dimensions of the nickel-titanium wire used for its design: 0.016" × 0.022", 0.017" × 0.025", and 0.018" × 0.025". The loops were tested on the Orthodontic Force Tester machine at an interbracket distance of 23 mm and activated 9 mm. The force in the y-axis and the moment in the x-axis were registered while the calculated moment to force ratio was recorded at each .5 mm of deactivation. The data were analyzed by three analyses of variance of repeated measures to detect differences and interactions between deactivation and wire size on force, moment, and moment-force ratios (M/F). RESULTS: All groups had significantly different forces (P < .001). The 0.016" × 0.022" wire produced 1.78N of force while the 0.017" × 0.025" and the 0.018" × 0.025" produced 2.81 N and 3.25 N, respectively. The 0.016" × 0.022" wire produced lower moments (11.6 Nmm) than the 0.017" × 0.025" and 0.018" × 0.025" wires, which produced similar moments (13.9 Nmm and 14.4Nmm, respectively). The M/F produced was different for all groups; 0.016" × 0.022" T-loops produced 6.7 mm while the 0.017" × 0.025" and 0.018" × 0.025" T-loops produced 5.0 mm and 4.5 mm, respectively. An interaction was detected for all variables between deactivation and groups. CONCLUSION: The larger wires tested produced higher forces with slight increase on the moments, but the M/F produced by the 0.016" × 0.022" wire was the highest found.