In Silico Mechanical Effort Analysis of the All-On-4 Design Performed With Platform-Switching Distal Short Dental Implants.

Short dental implants with platform matching connection have been used for the rehabilitation of atrophic jaws whenever standard-length dental implants cannot be placed without prior bone augmentation. Yet, there remains a lack of data regarding the risk of technical failures when the all-on-4 configuration is performed in atrophic jaws with platform-switching distal short dental implants. Thus, the current study used the finite element method to evaluate the mechanical behavior at the level of the prosthetic components of the all-on-4 concept performed in atrophic mandible using short-length distal implants with platform switching (PSW) connection. Three models of the all-on-4 configuration were generated in human atrophic mandibles. The geometric models consisted of PSW connection tilted standard (AO4T; θ = 30 deg; 11 mm-length), straight standard (AO4S; θ = 0 deg; 11 mm-length) and straight short (AO4Sh; θ = 0 deg; 8 mm-length) distal implants. A resultant force of 300 N was performed obliquely in the left side and posterior region of the prosthetic bar. The von Mises equivalent stress (σvm) and maximum and minimum principal stresses (σmax and σmin) were performed at level of the prosthetic components/implants and peri-implant bone crest, respectively. The general displacement of the models was also evaluated. The stress analysis was performed on the side of load application. The AO4S configuration showed the lowest values of σvm in the mesial left (ML) and distal left (DL) abutments (37.53 MPa and 232.77 MPa, respectively) and dental implants (91.53 MPa and 231.21 MPa, respectively). The AO4Sh configuration showed the highest values of σvm in the bar screw (102.36 MPa), abutment (117.56 MPa), and dental implant (293.73 MPa) of the ML area. Among the models, the highest values of σmax and σmin were noticed in the peri-implant bone crest of the AO4T design (131.48 MPa and 195.31 MPa, respectively). All models showed similar values of general displacements, which were concentrated in the mandible symphysis. The all-on-4 configurations designed with PSW connection and tilted standard (AO4T; θ = 30 deg; 11 mm-length), straight standard (AO4S; θ = 0 deg; 11 mm-length) or straight short (AO4Sh; θ = 0 deg; 8 mm-length) distal implants were not associated with higher odds of technical failures. The AO4Sh design may be a promising option for the prosthetic rehabilitation of atrophic jaws.

Bacterial response to Ti-35Nb-7Zr-5Ta alloy incorporated with calcium, phosphate and magnesium.

High implant survival rates have been achieved in recent decades due to continual modifications in implant design and surface topography, however there is still an ongoing quest to control peri-implant bone loss. The objective of this work was to develop Ti-35Nb-7Zr-5Ta (TNZT) alloys, perform physicochemical and morphological characterization of their surface modified by electrolytic oxidative plasma technique with ions related to osseointegration and lastly evaluate bacterial colonization in vitro. Three groups were evaluated: C group (polished TNZT), CaP group (sodium ß glycerophosphate + calcium acetate) and Mg group (magnesium acetate). Before and after anodizing the surfaces, physicochemical and morphological analyses were performed: scanning electron microscopy with field emission gun (FEG-SEM), energy dispersion spectroscopy (EDS), X-ray diffraction (DRX), wettability (goniometer) and roughness (rugometer). Controlled and treated specimens were contaminated with unstimulated saliva collected from 10 healthy volunteers. Then, biofilm samples were collected and up to 35 microbial species, including commensal and pathogenic microorganisms, were identified and quantified by the Checkerboard DNA-DNA Hybridization method. The CaP group modified the surface morphology in the form of pores, while the Mg group modified it in the form of flakes. The contact angle was significantly smaller in the CaP group. The average roughness was higher in the CaP and Mg groups. A smaller total amount of bacteria was identified in the Mg group and relevant differences were found in the microbial profile associated with different surface treatments. Therefore, considering the microbiological profile and for the prevention of peri-implantitis, the Mg group presented more satisfactory and encouraging results for the manufacture of dental implants.

Strontium-loaded titanium-15molybdenum surface improves physicochemical and biological propertiesin vitro.

The titanium alloy composition and microdesign affect the dynamic interplay between the bone cells and titanium surface in the osseointegration process. The current study aimed to evaluate the surface physicochemical properties, electrochemical stability, and the metabolic response of the MC3T3-E1 cells (pre-osteoblast cell line) cultured onto titanium-15molybdenum (Ti-15Mo) discs treated with phosphoric acid (H3PO4) and sodium hydroxide (NaOH) and/or strontium-loading by the hydrothermal method. The x-ray dispersive energy spectroscopy (EDS) and x-ray diffraction (XRD) analysis showed no trace of impurities and the possible formation of hydrated strontium oxide (H2O2Sr), respectively. The confocal laser microscopy (CLSM) analysis indicated that titanium samples treated with strontium (Sr) showed greater surface roughness. The acid/alkali treatment prior to the hydrothermal Sr deposition improved the surface free energy and resistance to corrosion of the Ti-15Mo alloy. The acid/alkali treatment also provided greater retention of the Sr particles on the Ti-15Mo surfaces accordingly with inductively coupled plasma optical emission spectrometry (ICP-OES) analysis. The AlamarBlue and fluorescence analysis indicated noncytotoxic effects against the MC3T3-E1 cells, which allowed cells' adhesion and proliferation, with greater cells' spreading in the Sr-loaded Ti-15Mo samples. These findings suggest that Sr deposition by the hydrothermal method has the potential to enhance the physicochemical properties of the Ti-15Mo previously etched with H3PO4and NaOH, and also improve the initial events related to cell-mediated bone deposition.

Microbial Adhesion and Biofilm Formation on Bioactive Surfaces of Ti-35Nb-7Zr-5Ta Alloy Created by Anodization.

This study evaluated the microbial colonization (adhesion and biofilm) on modified surfaces of a titanium alloy, Ti-35Nb-7Zr-5Ta, anodized with Ca and P or F ions, with and without silver deposition. The chemical composition, surface topography, roughness (Ra), and surface free energy were evaluated before and after the surface modifications (anodizing). Adhesion and biofilm formation on saliva-coated discs by primary colonizing species (Streptococcus sanguinis, Streptococcus gordonii, Actinomyces naeslundii) and a periodontal pathogen (Porphyromonasgingivalis) were assessed. The surfaces of titanium alloys were modified after anodizing with volcano-shaped micropores with Ca and P or nanosized with F, both with further silver deposition. There was an increase in the Ra values after micropores formation; CaP surfaces became more hydrophilic than other surfaces, showing the highest polar component. For adhesion, no difference was detected for S. gordonii on all surfaces, and some differences were observed for the other three species. No differences were found for biofilm formation per species on all surfaces. However, S. gordonii biofilm counts on distinct surfaces were lower than S. sanguinis, A. naeslundii, and P. gingivalis on some surfaces. Therefore, anodized Ti-35Nb-7Zr-5Ta affected microbial adhesion and subsequent biofilm, but silver deposition did not hinder the colonization of these microorganisms.

Potentialities and limitations of computer-aided design and manufacturing technology in the nonextraction treatment of Class I malocclusion.

INTRODUCTION: Computer-aided design and manufacturing (CAD-CAM) systems have assisted orthodontists to position brackets virtually. The purpose of this study was to evaluate if a CAD-CAM system could predict the orthodontic treatment outcome of patients with Angle Class I malocclusion with mild crowding or spacing and with no need for orthodontic extraction. METHODS: Using the American Board of Orthodontics Cast-Radiograph Evaluation (ABO-CRE) and color map superimposition, the treated occlusion was compared with the virtual final occlusion of 24 young adults with Class I occlusion. Using eXceed software (eXceed, Witten, Germany), we created the final occlusion prediction for each patient (virtual set up group). A digital model of the final occlusion of each patient was created (treated occlusion group). ABO-CRE score was used to compare groups. In addition, a color map was created for all subjects to access the mean and range values between the virtual set up model and treated occlusion model of each patient. Random and systematic errors were calculated. In addition, chi-square and t test were used. RESULTS: Comparisons between virtual set up occlusion and treated occlusion showed statistically significant differences in 3 out of 7 measurements: interproximal contact score was larger for treated than virtual occlusion (0.45 mm and 0.04 mm, respectively), and the treated occlusion showed larger values than the virtual occlusion for occlusal contacts (14.13 mm and 7.62 mm, respectively) and overjet (7.37 mm and 0.66 mm, respectively). Although the treated occlusion showed a larger score than the virtual occlusion (50.41 mm and 34.58 mm, respectively), there is no significant difference between both. Root angulation decreased (from 1.95 ± 1.29 to 0.65 ± 0.71) because of the treatment. CONCLUSIONS: ABO-CRE overall score presents no difference between groups. In addition, CAD-CAM setup occlusion closely predicts the final teeth alignment and leveling with interarch relationships showing less ABO-CRE score deduction.

Effect of Cleanser Solutions on the Retention Force of O'ring Attachment: An in Vitro Study.

The aim of this study was to evaluate the effect of cleaning solutions on the retention force of o-ring-type overdenture attachments. The effect of four solutions on nitrile rings were evaluated: Cepacol (C), Cepacol with fluoride (CF), Listerine (L) and 0.05% sodium hypochlorite (SH); deionized water (DW) was used as a control. Matrices containing two implants and abutments and acrylic specimens with the metal capsules were obtained and divided into the groups. A simulation of 90 overnight immersions (8 h) was performed, and the tensile strength value was obtained at the beginning (T0) and in every 30 days (T1, T2 and T3) (n=6). In order to analyze o-ring surface damage after the immersions, a scanning electron microscopy (SEM) was used (n=1). For statistical analysis of the results, analysis of variance (ANOVA) and multiple comparisons with Bonferroni adjustment (test power=1.000; a=0.05) were used. There was a significant difference for the factors time (p<0.001), solution (p<0.001) and for the interaction time × solution (p<0.001). Considering the times of each solution, only for DW there was no significant loss of retention over time. Comparing the solutions in each moment, there was no difference among the solutions in T0. From T1, CF and SH provided less retention than DW (p<0.005). Through SEM it was possible to observe changes in the surface of the CF and SH nitrile o-rings. CF and SH should be avoided due to deleterious action in o-rings.

Effect of cleanser solutions on the retention force of oring attachment: an in vitro study

Abstract The aim of this study was to evaluate the effect of cleaning solutions on the retention force of o-ring-type overdenture attachments. The effect of four solutions on nitrile rings were evaluated: Cepacol (C), Cepacol with fluoride (CF), Listerine (L) and 0.05% sodium hypochlorite (SH); deionized water (DW) was used as a control. Matrices containing two implants and abutments and acrylic specimens with the metal capsules were obtained and divided into the groups. A simulation of 90 overnight immersions (8 h) was performed, and the tensile strength value was obtained at the beginning (T0) and in every 30 days (T1, T2 and T3) (n=6). In order to analyze o-ring surface damage after the immersions, a scanning electron microscopy (SEM) was used (n=1). For statistical analysis of the results, analysis of variance (ANOVA) and multiple comparisons with Bonferroni adjustment (test power=1.000; a=0.05) were used. There was a significant difference for the factors time (p<0.001), solution (p<0.001) and for the interaction time × solution (p<0.001). Considering the times of each solution, only for DW there was no significant loss of retention over time. Comparing the solutions in each moment, there was no difference among the solutions in T0. From T1, CF and SH provided less retention than DW (p<0.005). Through SEM it was possible to observe changes in the surface of the CF and SH nitrile o-rings. CF and SH should be avoided due to deleterious action in o-rings.

Resumo O objetivo do estudo foi avaliar o efeito de soluções higienizadoras sobre a força de retenção de encaixes do tipo o-ring. Foram avaliadas quatro soluções: Cepacol (C); Cepacol com flúor (CF), Listerine (L), hipoclorito de sódio 0,05% (HS) e água deionizada (controle/AD) em o-rings de nitrilo. Matrizes contendo dois implantes e pilares e espécimes em acrílico com as cápsulas metálicas foram obtidas e divididas entre os grupos. Foi realizada a simulação de 90 imersões noturnas (8 h), sendo obtido o valor da resistência à tração no início e a cada 30 dias (T0, T1, T2 e T3) por meio da máquina de ensaios mecânicos (n=6). Microscopia eletrônica de varredura (MEV) foi utilizada para análise de danos na superfície do o´ring após a imersão (n=1). Para análise estatística dos resultados foi utilizada análise de variância (ANOVA) e múltiplas comparações com ajuste de Bonferroni (poder do teste=1,000; a=0,05). Houve diferença significante para os fatores tempo (p<0,001), solução (p<0,001) e para interação de tempo × solução (p<0,001). Considerando-se os tempos de cada solução, apenas AD não apresentou perda significativa de retenção ao longo do tempo. Comparando as soluções em cada momento, não houve diferença entre as soluções em T0. A partir de T1, CF e HS propiciaram menor retenção quando comparados à AD (p <0,005). Através do MEV foi possível observar alterações nas superfícies dos o-rings de nitrilo imersos em CF e HS. O Cepacol com flúor e hipoclorito de sódio devem ser evitados devido à ação deletéria nos o-rings.

Comparison of Ti-35Nb-7Zr-5Ta and Ti-6Al-4V hydrofluoric acid/magnesium-doped surfaces obtained by anodizing.

OBJECTIVES: Development of a new generation of stable ß alloy, free of aluminum or vanadium and with better biological and mechanical compatibility and evaluate the surface properties of Ti-6Al-4V and Ti-35Nb-7Zr-5Ta after anodization in hydrofluoric acid, followed by deposition of different electrolyte concentrations of magnesium particles by micro arc-oxidation treatment. METHODS: Disks were anodized in hydrofluoric acid. After this first anodization, the specimens received the deposition of magnesium using different concentration (8.5% and 12.5%) and times (30s and 60s). The surface morphology was assessed using scanning electron microscopy, and the chemical composition was assessed using energy dispersive x ray spectroscopy. The surface free energy was measured from the contact angle, and the mean roughness was measured using a digital profilometer. RESULTS: Anodization in hydrofluoric acid provided the formation of nanotubes in both alloys, and the best concentration of magnesium considered was 8.5%, as it was the condition where the magnesium was incorporated without covering the morphology of the nanotubes. X-ray dispersive energy spectroscopy showed magnesium incorporation in all conditions. The average roughness was increased in the Ti-35Nb-7Zr-5Ta alloy. CONCLUSIONS: It was concluded that anodizing could be used to deposit magnesium on the surfaces of Ti-6Al-4V and Ti-35Nb-7Zr-5Ta nanotubes, with better results obtained in samples with magnesium concentration in 8.5% and the process favored the roughness in the Ti-35Nb-7Zr-5Ta group.

Effect of Yd:YAG laser irradiation on the shear bond strength of orthodontic metal brackets.

OBJECTIVE: The purpose of this study was to evaluate the effect of the Yd:YAG laser irradiation on orthodontic bracket base surface. Shear bond strength (SBS) values and sites of the bonding failure interfaces were quantified. METHODS: Brackets were divided into two groups: OP (One Piece - integral sandblast base) and OPL (One Piece - laser irradiation). The brackets were randomly bonded on an intact enamel surface of 40 bovine incisors. The SBS tests were carry out using a universal test machine. A stereomicroscopy was used to evaluate the adhesive remnant index (ARI), and surface characterization was performed by scanning electron microscopy (SEM). Student's t-test was used to compare the SBS between the two groups (p< 0.05). Frequencies and chi-square analysis were applied to evaluate the ARI scores. RESULTS: OPL group showed higher value (p< 0.001) of SBS than OP group (43.95 MPa and 34.81 MPa, respectively). ARI showed significant difference (p< 0.001) between OPL group (ARI 0 = 100%) and OP group (ARI 0 = 15%). SEM showed a higher affinity between the adhesive and the irradiated laser base surface. CONCLUSIONS: Yd:YAG laser irradiation on bracket base increased SBS values, showing that bonding failure occurs at the enamel/adhesive interface. Laser-etched bracket base may be used instead of conventional bases in cases where higher adhesion is required, reducing bracket-bonding failure.

Effect of Yd: YAG laser irradiation on the shear bond strength of orthodontic metal brackets

ABSTRACT Objective: The purpose of this study was to evaluate the effect of the Yd:YAG laser irradiation on orthodontic bracket base surface. Shear bond strength (SBS) values and sites of the bonding failure interfaces were quantified. Methods: Brackets were divided into two groups: OP (One Piece - integral sandblast base) and OPL (One Piece - laser irradiation). The brackets were randomly bonded on an intact enamel surface of 40 bovine incisors. The SBS tests were carry out using a universal test machine. A stereomicroscopy was used to evaluate the adhesive remnant index (ARI), and surface characterization was performed by scanning electron microscopy (SEM). Student's t-test was used to compare the SBS between the two groups (p< 0.05). Frequencies and chi-square analysis were applied to evaluate the ARI scores. Results: OPL group showed higher value (p< 0.001) of SBS than OP group (43.95 MPa and 34.81 MPa, respectively). ARI showed significant difference (p< 0.001) between OPL group (ARI 0 = 100%) and OP group (ARI 0 = 15%). SEM showed a higher affinity between the adhesive and the irradiated laser base surface. Conclusions: Yd:YAG laser irradiation on bracket base increased SBS values, showing that bonding failure occurs at the enamel/adhesive interface. Laser-etched bracket base may be used instead of conventional bases in cases where higher adhesion is required, reducing bracket-bonding failure.

RESUMO Objetivo: O objetivo do presente estudo foi avaliar o efeito da aplicação do laser Yd:YAG sobre a superfície metálica da base de braquetes ortodônticos, a resistência da colagem ao cisalhamento (RU) e os locais das falhas nas interfaces adesivas. Métodos: Os braquetes foram divididos em dois grupos, de acordo com o tipo de base: OP (One Piece - monobloco, base jateada) e OPL (One Piece - monobloco, base irradiada a laser). Foram selecionados 40 incisivos bovinos hígidos para a colagem de braquetes na superfície do esmalte. Os testes de RU foram realizados por meio de uma máquina de ensaio universal EMIC DL1000. O Índice de Adesivo Remanescente (ARI) e a caracterização das superfícies foram realizados empregando-se estereomicroscópio e microscópio eletrônico de varredura (MEV). O teste t de Student foi aplicado para comparar a RU entre os dois grupos (p< 0,05). O ARI foi avaliado por meio da análise de Frequência e teste do Qui-quadrado. Resultados: O grupo OPL obteve maiores valores de RU (p<0,001) do que o grupo OP (43,95 MPa e 34,81 MPa, respectivamente), e o ARI obteve diferença significativa (p<0,001) entre os grupos OPL (ARI 0 = 100%) e OP (ARI 0 = 15%). A análise proveniente do MEV mostrou alta interação adesiva entre a resina e a superfície metálica da base irradiada pelo feixe de laser. Conclusões: A irradiação com laser Yd:YAG sobre a superfície da base de braquetes metálicos aumentou os valores da RU, demonstrando que as falhas adesivas ocorreram na interface esmalte/adesivo. O uso de braquetes modificados com irradiação a laser pode ser adotado como alternativa aos braquetes com bases convencionais nos casos em que uma maior retentividade for requerida para reduzir as falhas de adesividade.

Proteome analysis of the salivary pellicle formed on titanium alloys containing niobium and zirconium.

The chemical composition of biomaterials can drive their biological responses; therefore, this in vitro study aimed to evaluate the proteomic profile of the salivary pellicle formed on titanium (Ti) alloys containing niobium (Nb) and zirconium (Zr). The experimental groups consisted of Ti35NbxZr (x = 5 and 10 wt%) alloys, and commercially pure titanium (cpTi); titanium aluminium vanadium (Ti6Al4V) alloys were used as controls. The physical and chemical characteristics of the Ti materials were analysed. The proteomic profile was evaluated by liquid chromatography coupled with tandem mass spectrometry. Bacterial adhesion (2 h) of mixed species (Streptococcus sanguinis and Actinomyces naeslundii) was investigated as colony-forming units (n = 6). This paper reports the finding that salivary pellicle composition can be modulated by the composition of the Ti material. The Ti35NbxZr group showed a significant ability to adsorb proteins from saliva, which can favour interactions with cells and compatibility with the body.

O uso da tecnologia CAD/CAM na Ortodontia ­ setup ortodôntico e colagem indireta pelo sistema eXceed™ / The CAD/CAM technology in Orthodontics ­ Orthodontic setup and indirect bonding using the eXceedTM System

Os sistemas CAD/CAM, incluindo o sistema eXceed™, possibilitam aos ortodontistas a realização de diagnóstico, planejamento de casos clínicos e posicionamento virtual de bráquetes. A posição de cada acessório, determinada pelo software, é transferida para o modelo tridimensional do paciente sobre o qual um dispositivo de transferência para colagem indireta (CI) de bráquetes é produzido. A CI permite uma melhoria na precisão da colagem de acessórios ortodônticos, diminuindo o tempo e o custo do tratamento devido a uma menor necessidade de dobras de finalização e reposicionamento de bráquetes. O caso clínico apresentado tem o objetivo de apresentar um tratamento ortodôntico utilizando o método de CI com posicionamento virtual de bráquetes idealizado pelo sistema eXceed™. O posicionamento dos bráquetes programado pelo sistema eXceed™ permitiu um posicionamento "ideal" dos dentes dispensando a implementação de dobras de finalização e proporcionando uma oclusão equilibrada. Essa nova tecnologia demonstrou ser eficiente e eficaz, e o setup ortodôntico fornecido pelo sistema ficou acordante com o resultado final do tratamento ortodôntico (AU)

CAD/CAM systems, including the eXceed™ system, allow orthodontists to perform diagnosis, treatment plan, and brackets virtual positioning. The positioning of each bracket, determined by the software, is transferred to a tridimensional patient model enabling to build an indirect bonding (IB) tray. IB allows improvement in the ideal bracket positioning, decreasing treatment time and cost due to less detailed finishing bends and/or bracket repositioning. The clinical case report purpose is to present an orthodontic treatment using IB with virtual bracket positioning using eXceed™ system. The bracket virtual positioning from eXceed™ system allowed an ideal final teeth positioning eliminating detailed finishing bends and reaching the ideal occlusion as planned. This new technology has shown to be efficient and effective, and the virtual tridimensional orthodontic setup has been in agreement with the final treatment occlusion (AU)

Acurácia e confiabilidade de modelos digitais tridimensionais ­ validação do software eXceedtm / Three-dimensional digital models accuracy and reliability ­ eXceedtm software validation

Resumo Introdução: Os sistemas CAD/CAM auxiliam ortodontistas na confecção de alinhadores estéticos e na colagem indireta (posicionamento virtual de bráquetes) em modelos digitais tridimensionais. Este estudo avaliou a precisão e validade do software eXceedTM. Métodos: Vinte modelos de gesso de pacientes foram digitalizados utilizando um escâner de mesa e os arquivos obtidos foram convertidos em estereolitografia pelo software OrthoAnalyserTM. Utilizando os modelos de gesso e digital, seis medidas foram aferidas: Largura Intermolares (LM), Largura Intercaninos (LC), Comprimento do Arco posterior (CA), Diâmetro da Coroa do Pré-Molar (DP), Altura da Coroa do Canino (AC) e Overjet (OJ). Os erros sistemáticos e aleatórios foram avaliados em análises das réplicas das mensurações. As diferenças foram avaliadas usando o teste t de Student. Os erros aleatórios foram quantificados usando o erro do método (V(Sd2/2n) e o Coeficiente de Correlação Intraclasse (ICC). Resultados: Duas das medidas das réplicas em modelos digitais (CA) e de gesso (LC) demostraram erros sistemáticos estatisticamente significativos. O ICC variou de 0,916 a 0,997. Os erros do método foram todos inferiores a 0,41 mm (0,22 mm). Os gráficos de Bland-Altman mostraram que as diferenças de repetitividade entre os dois métodos estavam dentro dos limites de concordância. Os valores DP (0,253 mm), LC (0,396 mm), AC (0,314 mm) e CA (0,359 mm) foram maiores em modelos de gesso do que nos modelos digitais. Conclusão: As medidas realizadas em ambos os métodos foram confiáveis e reprodutíveis, e as medidas dos modelos de gesso foram ligeiramente maiores do que os dos modelos digitais correspondentes (AU)

Abstract Introduction: CAD/CAM systems help orthodontists in the production of aesthetic aligners and in indirect bonding (virtual bracket positioning) in three-dimensional digital models. This study evaluated the accuracy and validity of the eXceedTM 3D software (Roosikrantsi, Tallinn, Estonia). Methods: Twenty patient plaster models were digitized by a desktop scanner, and the files obtained were converted to stereolithography by OrthoAnalyserTM software. Using the cast and digital models, six measurements were performed: Intermolar Width (LM); Intercanine Width (LC); Posterior Arch Length (CA); Premolar Crown Diameter (DP); Canine Crown Hight (AC) and Overjet (OJ). Intra-observer systematic differences between the replicates were described with mean absolute differences and standard errors (SE); differences were assessed using a paired Students t test. Random errors were quantified using the method error statistic (V[Sd2/2n]) and Intraclass Correlation Coefficient (ICC). Differences between methods was evaluated using Students t test. Results: Two of the measurements of the replicas in the digital model (CA) and in the plaster model (LC) showed statistically significant systematic errors. The ICC ranged from 0.916 to 0.997. The method errors were all less than 0.41 mm (0.22 mm). Bland-Altman plots showed that the differences of repeatability between the two methods were within the limits of agreement. The values DP (0.253 mm), LC (0.396 mm), AC (0.314 mm) and CA (0.359 mm) were higher in plaster models than in digital models. Conclusion: The measurements performed in both methods were reliable and reproducible, and plaster models measurements were slightly higher than those of the corresponding digital models. (AU)

Goal scoring frequency in soccer in diff erent age groups / Frequência de gols marcados no futebol em diferentes faixas etárias

Scoring goals is the main objective and a key factor to success in soccer. Therefore, all the aspects of this important performance indicator must be studied. Many authors have proposed to study diff erent aspects related to goal scoring in soccer. However, most of these studies include adult players from professional or amateur teams. The aim of the present study was to analyze the goal scoring frequency in 388 soccer matches of Professional, Under-20 and Under-17 competitions from Brazil. The impact of the fi rst goal scored on the match outcome was also studied. The frequency of 1100 goals was analyzed by dividing the game in two (fi rst and second half) and six equal periods of time. Data showed a greater number of goals scored over time with a higher percentage of goals scored in second half in Professional, Under-20 and Under-17 competitions, respectively, 55.9% (P=0.036), 59.5% (P=0.000) and 55.6% (P=0.020), especially in the last period of the game, respectively, 21.5% (P=0.084), 26.2% (P=0.000) and 22.1% (p=0.009). It was also found that scoring the fi rst goal had an important infl uence on the match outcome with a percentage of 65.3% (P=0.000), 71.5% (P=0.000), and 75.4% (P=0.000), respectively, of the matches won by the team scoring fi rst. It was concluded that, despite diff erences in age and expertise among the players of the three age brackets, the results regarding the goal scoring frequency and the infl uence of the fi rst goal on the match outcome were similar in all competitions....(AU)

Marcar gols é o principal objetivo e a chave para o sucesso no futebol. Portanto, todos os aspectos relacionados a este importante indicador de desempenho devem ser estudados. Diversos autores se propuseram a estudar diferentes aspectos relacionados à marcação de gols no futebol, tratando-se, contudo, na sua maioria, de estudos com adultos em equipes profissionais ou amadoras. O presente estudo se propôs a analisar a frequência dos gols marcados em 388 partidas de futebol em competições Profissional, Sub-20 e Sub-17 no Brasil. O impacto do primeiro gol marcado no resultado final das partidas também foi estudado. A frequência de 1100 gols foi analisada dividindo-se as partidas em dois (primeiro e segundo tempo) e seis períodos iguais de tempo. Os dados apontaram um maior número de gols marcados com o passar do tempo com um percentual maior de gols marcados no segundo tempo nas três competições, respectivamente 55.9% (P=0.036), 59.5% (P=0.000) e 55.6% (P=0.020), e, especialmente, no último período do jogo, respectivamente, 21.5% (P=0.084), 26.2% (P=0.000) e 22.1% (P=0.009). Além disso, os resultados mostraram que marcar o primeiro gol teve uma importante influência no resultado final das partidas com um percentual de 65.3% (P=0.000), 71.5% (P=0.000), e 75.4% (P=0.000), respectivamente, dos jogos vencidos pela equipe que marcou o primeiro gol. Concluiu-se que, apesar das diferenças de idade e expertise dentre os jogadores das equipes de diferentes categorias, os resultados relacionados à frequência de gols marcados e à influência do primeiro gol no resultado final das partidas foram semelhantes nas três competições....(AU)

Evaluation of primary stability in modified implants: Analysis by resonance frequency and insertion torque.

BACKGROUND: Changes in the macrogeometry of dental implants are known to influence primary stability and the osseointegration process. PURPOSE: The purpose of the present in vitro study was to evaluate the mechanical behavior of geometric changes in the apex region of dental implants. METHODS: Thirty-five cylindrical dental implants (Titamax Ti; Neodent) were machined at the apical third to reproduce the experimental groups: without apical cut (Wc), apical bi-split cut, apical tri-split cut, apical quadri-split cut (Qs). One (control group) (Titamax Ti Ex) (n = 7) without any modifications was added. The implants had the same final dimensions (4.1 x 11 mm2 ). All implants were inserted into artificial bone blocks and were evaluated by insertion torque and resonance frequency by ISQ values (Osstell). Two-tailed analysis of variance (One-way ANOVA) and Tukey's post-test (P < .05). RESULTS: Control and Qs implants showed a significant increase of the insertion torque (P < .001). For the resonance frequency, Wc and (control) implants had the greatest ISQ values. However, there's no significant difference between (control) and Qs for the ISQ values (P < .001). CONCLUSION: Within the limitations of the present study, the proposed geometries at the apical third of dental implants greatly influenced its insertion torque and primary stability in vitro.

Physical and physiological differences of backs and forwards from the Brazilian National rugby union team.

BACKGROUND: The aim of this study was to compare backs and forwards rugby union players recruited to a National team in the following physical and physiological indicators: anthropometrics, squat jump (SJ), countermovement jump (CMJ), 10- and 30-meter sprint, resting heart rate variability (HRV), Yo-Yo Test and heart rate (HR) at 2 minutes of test. METHODS: The measurements were performed on the first day of a training camp planned to finely select the players who would participate in the 2016 America's Rugby Championship. The magnitude-based inference was used in the comparisons. RESULTS: Backs demonstrated almost certainly greater distance in the Yo-Yo Test (backs: 2305.9±231.3 meters; forwards: 1802.4±361.2 meters), higher vertical jump height in both SJ and CMJ (SJ: 44.0±5.3 cm vs. 37.6±5.4 cm; CMJ: 46.1±5.0 cm vs. 40.0±5.5 cm, for backs and forwards respectively), and superior sprint velocity in 10- and 30-m (10-m: 6.02±0.23 m.s-1 vs. 5.51±0.34 m.s-1; 30-m: 7.46±0.25 m.s-1 vs. 6.89±0.37 m.s-1, for backs and forwards respectively) than the forwards. In contrast, forwards were almost certainly taller and heavier than backs, and displayed higher sprint momentum in 10- and 30-meters (10 meters: 513.0±51.6 kg.m.s-1 vs. 598.4±53.1 kg.m.s-1; 30 meters: 635.3±56.1 kg.m.s-1 vs. 749.0±70.5 kg.m.s-1, for backs and forwards respectively). The submaximal HR in the first 2-minutes of the Yo-Yo test was likely lower in the backs than in the forwards (77.6±5.1% of the maximal HR vs. 81.3±5.4% of the maximal HR for backs and forwards respectively), while HRV indices were not different between backs and forwards. CONCLUSIONS: Playing position appears to be determined by the players' physical and physiological characteristics in top-level rugby union, and the submaximal HR measured during Yo-Yo test can be a simple alternative to discriminate backs and forwards.

Surface properties of Ti-35Nb-7Zr-5Ta: Effects of long-term immersion in artificial saliva and fluoride solution.

STATEMENT OF PROBLEM: The mechanical properties of new titanium alloys with an elastic modulus closest to cortical bone have been studied. However, potentially damaging conditions experienced in the oral cavity, such as fluoride ions, can initiate a localized or crevice process of corrosive degradation in the alloy surfaces. PURPOSE: The purpose of this in vitro study was to evaluate the effects of long-term immersion in artificial saliva or in fluoride solution on mean roughness (Ra), Vickers hardness, and topography of the new titanium alloy Ti-35Nb-7Zr-5Ta (TNZT) compared with those of cp Ti and Ti-6Al-4V (TAV). MATERIAL AND METHODS: Disks (N=210) were divided into cp Ti, TAV, and TNZT and subdivided according to the following treatments: no immersion (N(-), control), immersion in artificial saliva (S), and immersion in fluoride (F) during periods equivalent to 5, 10, 15, and 20 years. The Ra and Vickers hardness were measured with a profilometer and a hardness tester. The topography was analyzed by scanning electronic microscopy. Data were compared using the Kruskal-Wallis and Dunn tests (α=.05). RESULTS: Values of Ra and hardness were significantly different among the metals (Ra: TAV

Differences in the force system delivered by different beta-titanium wires in elaborate designs.

OBJECTIVE: Evaluation of the force system produced by four brands of b-Ti wires bent into an elaborate design. METHODS: A total of 40 T-loop springs (TLS) hand-bent from 0.017 x 0.025-in b-Ti were randomly divided into four groups according to wire brand: TMATM(G1), BETA FLEXYTM (G2), BETA III WIRETM (G3) and BETA CNATM (G4). Forces and moments were recorded by a moment transducer, coupled to a digital extensometer indicator adapted to a testing machine, every 0.5 mm of deactivation from 5 mm of the initial activation. The moment-to-force (MF) ratio, the overlapping of the vertical extensions of the TLSs and the load-deflection (LD) ratio were also calculated. To complement the results, the Young's module (YM) of each wire was determined by the slope of the load-deflection graph of a tensile test. The surface chemical composition was also evaluated by an energy dispersive X-ray fluorescence spectrometer. RESULTS: All groups, except for G2, produced similar force levels initially. G3 produced the highest LD rates and G1 and G4 had similar amounts of overlap of the vertical extensions of the TLSs in "neutral position". G1 and G3 delivered the highest levels of moments, and G2 and G3 produced the highest MF ratios. b-Ti wires from G3 produced the highest YM and all groups showed similar composition, except for G2. CONCLUSION: The four beta-titanium wires analyzed produced different force systems when used in a more elaborate design due to the fact that each wire responds differently to bends.

Differences in the force system delivered by different beta-titanium wires in elaborate designs

Abstract Objective: Evaluation of the force system produced by four brands of b-Ti wires bent into an elaborate design. Methods: A total of 40 T-loop springs (TLS) hand-bent from 0.017 x 0.025-in b-Ti were randomly divided into four groups according to wire brand: TMATM(G1), BETA FLEXYTM (G2), BETA III WIRETM (G3) and BETA CNATM (G4). Forces and moments were recorded by a moment transducer, coupled to a digital extensometer indicator adapted to a testing machine, every 0.5 mm of deactivation from 5 mm of the initial activation. The moment-to-force (MF) ratio, the overlapping of the vertical extensions of the TLSs and the load-deflection (LD) ratio were also calculated. To complement the results, the Young's module (YM) of each wire was determined by the slope of the load-deflection graph of a tensile test. The surface chemical composition was also evaluated by an energy dispersive X-ray fluorescence spectrometer. Results: All groups, except for G2, produced similar force levels initially. G3 produced the highest LD rates and G1 and G4 had similar amounts of overlap of the vertical extensions of the TLSs in "neutral position". G1 and G3 delivered the highest levels of moments, and G2 and G3 produced the highest MF ratios. b-Ti wires from G3 produced the highest YM and all groups showed similar composition, except for G2. Conclusion: The four beta-titanium wires analyzed produced different force systems when used in a more elaborate design due to the fact that each wire responds differently to bends.

Resumo Objetivo: avaliar os sistemas de força produzidos por quatro marcas de fios de -Ti, dobrados em formas complexas. Métodos: quarenta molas T-Loop (TLS) dobradas à mão, confeccionadas a partir de fios de -Ti, calibre 0,017" x 0,025", foram aleatoriamente divididas em quatro grupos, de acordo com a marca do fio: TMA (G1), BETA FLEXY (G2), BETA III Wire (G3) e BETA CNA (G4). Forças e momentos foram registrados por um transdutor de momento - acoplado a um extensômetro digital, adaptado a uma máquina de ensaios -, a cada 0,5mm de desativação, a partir de 5mm da ativação inicial. A proporção momento-força (M/F), a sobreposição das extensões verticais das TLSs e a relação carga-deflexão (C/D) também foram calculadas. Para completar os resultados, o módulo de Young (MY) de cada fio foi determinado pelo declive no gráfico de carga-deflexão em um ensaio de tração. Ademais, a composição química da superfície foi avaliada por um espectrômetro de fluorescência de raios X por energia dispersiva. Resultados: todos os grupos, exceto o G2, produziram níveis de força semelhantes, inicialmente. O G3 produziu as maiores taxas de C/D, enquanto G1 e G4 tiveram quantidades similares de sobreposição das extensões verticais das TLSs em posição neutra. G1 e G3 geraram os mais altos níveis de momentos, enquanto G2 e G3 produziram os mais altos índices de M/F. Os fios -Ti do G3 produziram o maior MY, e todos os grupos apresentaram composição semelhante, exceto G2. Conclusão: os quatro fios de beta-titânio analisados produziram diferentes sistemas de forças, quando utilizados para formas mais complexas, devido ao fato de que cada fio responde de forma diversa à confecção de dobras.

Pre-heating mitigates composite degradation

ABSTRACT Dental composites cured at high temperatures show improved properties and higher degrees of conversion; however, there is no information available about the effect of pre-heating on material degradation. Objectives This study evaluated the effect of pre-heating on the degradation of composites, based on the analysis of radiopacity and silver penetration using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS). Material and Methods Thirty specimens were fabricated using a metallic matrix (2x8 mm) and the composites Durafill VS (Heraeus Kulzer), Z-250 (3M/ESPE), and Z-350 (3M/ESPE), cured at 25°C (no pre-heating) or 60°C (pre-heating). Specimens were stored sequentially in the following solutions: 1) water for 7 days (60°C), plus 0.1 N sodium hydroxide (NaOH) for 14 days (60°C); 2) 50% silver nitrate (AgNO3) for 10 days (60°C). Specimens were radiographed at baseline and after each storage time, and the images were evaluated in gray scale. After the storage protocol, samples were analyzed using SEM/EDS to check the depth of silver penetration. Radiopacity and silver penetration data were analyzed using ANOVA and Tukey’s tests (α=5%). Results Radiopacity levels were as follows: Durafill VS<Z-350<Z-250 (p<0.05). The depth of silver penetration into the composites ranked as follows: Durafill VS>Z-350>Z-250 (p<0.05). After storage in water/NaOH, pre-heated specimens presented higher radiopacity values than non-pre-heated specimens (p<0.05). There was a lower penetration of silver in pre-heated specimens (p<0.05). Conclusions Pre-heating at 60°C mitigated the degradation of composites based on analysis of radiopacity and silver penetration depth.