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Coronavirus disease 2019 (COVID-19), a viral disease declared a pandemic by the World Health Organization (WHO) in March 2020, has posed great changes to many sectors of society across the globe. Its virulence and rapid dissemination have forced the adoption of strict public health measures in most countries, which, collaterally, resulted in economic hardship. This article is the first in a series of 3 that aims to contextualise the clinical impact of COVID-19 for the dental profession. It presents the epidemiological conditions of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), namely, its modes of transmission, incubation, and transmissibility period, signs and symptoms, immunity, immunological tests, and risk management in dental care. Individuals in dental care settings are exposed to 3 potential sources of contamination with COVID-19: close interpersonal contacts (

Objective: The purpose of this correlation study was to evaluate a possible association between the styloid process size and different craniofacial skeletal patterns, in the sagittal and the vertical planes. Methods: 59 consecutive orthodontic adult patients were selected. The styloid process length was measured on pretreatment panoramic radiographs and the cephalometric skeletal variables on lateral cephalometric radiographs. Data were analyzed using independent sample T-Tests, Mann-Whitney U Tests and Spearman´s partial correlations (=5%). Results: Males exhibited longer styloid processes than females (p=0.029), with a mean difference of 7.5mm. Within each individual, right and left styloid process length was similar (r= 0.77; p

Objectives: Esthetics is the main reason for seeking orthodontic treatment, demonstrating the importance of smile attractiveness in human relations. Therefore, this study aimed to quantify the influence of the smile and other facial components on overall facial attractiveness. Methods: Eight laypersons evaluated the attractiveness of 60 adults (30 men, 30 women) before orthodontic treatment using a visual analog scale. Pearson and stepwise correlations were carried out between the smiling face’s attractiveness and the attractiveness of the facial components: upper two-thirds, lower third, and smile. Results: For the entire sample, strong to moderate correlations were found between facial attractiveness and the smile (r = 0.71), the lower third (r = 0.70), and the upper two-thirds of the face (r = 0.42). When divided by gender, the facial parts’ correlation values were moderate and similar among each other in men, while in women, the face showed strong correlations with the smile (r = 0.83) and the attractiveness of the face’s lower third (r = 0.75). Conclusions: In general, correlations were found between the attractiveness of the smiling face and the components. In males, the lower third of the face accounted for 66% of the variation in facial attractiveness. In females, 83% of the variance in facial attractiveness could be ascribed to smile, with the value increasing only to 86% when the upper two-thirds were added.

Objectives: To evaluate the influence of the surface treatment and adhesive system on the shear bond strength and the failure mode of orthodontic brackets bonded to polymethylmethacrylate surfaces. Methods: Ninety metal brackets (n=15) were bonded to aged discs of polymethylmethacrylate SR Ivocron subjected to three surface conditions (no treatment; sandblasting with 50-μm aluminum oxide; roughening with a tungsten bur), using two combinations of adhesives (methylmethacrylate monomer + Transbond XT Primer; Scotchbond Universal Adhesive) followed by the composite Transbond XT. In the control group, metal brackets were bonded with Transbond XT to 15 human mandibular incisors. The specimens were thermocycled, stored in distilled water (37ºC, 7 days), and tested in shear, using an Instron universal machine. Failure mode was classified according to the adhesive remnant index using a stereomicroscope. The data were analyzed with an analysis of variance and posthoc tests (p

Objectives: This cephalometric study intended to evaluate pre-surgical changes in cephalometric variables on the lower third of the face produced by the orthodontic treatment, in patients with severe Class III malocclusions. Methods: The sample included 40 adults, divided into three groups: no-extractions (N), extractions for orthodontic reasons (E), and previous extractions for non-orthodontic reasons (E-NO). Student t-tests were used to evaluate the influence of orthodontic treatment on the cephalometric variables. An ANOVA was used for group comparisons before treatment and to compare the changes produced by the orthodontic treatment in the three groups. The significance level was established at 5%. Results: In Group E, significant (p

Introduction This cross-sectional study aimed to analyze the precision and trueness of dental models produced using 2 rapid prototyping 3-dimensional printers. Methods A digital crowded maxillary arch with a T-shaped base and 2 hemispheres of 2.5 mm radius was printed 10 times with a stereolithography apparatus (SLA) and digital light processing (DLP) in the highest precision and minimum layer thickness (z-resolution) mode. The copies were scanned using the D710 3Shape desktop scanner and assessed for precision and trueness via arch superimpositions and hemisphere measurements. Mann-Whitney U tests were used to compare trueness and precision among printers. Hemisphere radius was compared with the reference measurement and between 3-dimensional printers using 1 sample and independent Student t tests, respectively (α = 0.05). Results The root mean square values of arch superimpositions showed statistically significant differences between the 2 techniques, both for precision (P = 0.011): SLA (46.8 μm ± 13.5); DLP (111.1 μm ± 71.9), and trueness (P = 0.015): SLA (61.1 μm ± 9.8); DLP (99.8 μm ± 47.2). The color map model analysis indicated greater distortion on premolar and molar surfaces, with a higher range of contraction on the SLA and both contraction and expansion on the DLP. Anterior and posterior hemisphere radius registered increased values with DLP (1.7% and 0.49%) and reduced values with SLA (0.6% and 0.7%); however, only the anterior SLA hemispheres revealed a significant decrease from the reference value (P = 0.037). Conclusions In this study, the SLA printer was significantly different from the DLS printer, with the highest precision and trueness.

Introduction Esthetic improvement is a key motivator in undergoing orthodontic treatment. This study aims to quantify the contribution of the smile and other facial components to the overall esthetics of attractiveness. Methods The attractiveness of 60 subjects (30 men, 30 women), aged 18-35 years, before orthodontic treatment, was retrospectively evaluated by 8 laypersons using the Visual Analog Scale. Pearson and stepwise correlations were calculated between the attractiveness of the smiling face and the attractiveness of facial components; namely the smile, nose, eyes, hair, chin, eyebrows, and skin. Results A strong correlation between the face and smile attractiveness was found (r = 0.71) for the whole sample. No significant correlations were found between attractiveness and the other facial components. When divided by gender, the smile (r = 0.70) and the eyes (r = 0.51) correlated with the attractiveness of the smiling face for men. For women, the face registered a significant correlation with the smile (r = 0.83) and the skin (r = 0.37). Conclusions In general, smile attractiveness was strongly correlated with the attractiveness of the smiling face, which is the only significant component. For men, the smile was responsible for 49% of the variation in the attractiveness of the smiling face, the eyes for 22%, and the hair for 6%. For women, 69% of the variation in facial attractiveness could be attributed to smile.

Objectives: The objective of this study was to evaluate the effect of surface treatment and adhesive agent on the shear bond strength between a resin composite and an aged dental amalgam (356-days). Materials and Methods: Sixty amalgam (Tytin) disks were stored in water at 37oC for 365 days. Half of the specimens were airborne particle abraded and the remaining half was roughened with a greenstone. Resin composite cylinders (Tetric) were bonded onto the amal- gam surfaces using Amalgambond, All-Bond 2 or Scotchbond 1 (n=10). Specimens were stored in water at 37oC for 7 days and thermocycled. Shear bond strength testing was carried on an Instron Universal Testing Machine. Stereomicroscope examination was carried out to determine the bond failure sites. Results were analyzed by ANOVA followed by Student- Newman-Keuls' post-hoc tests and the level of statistical significance was set at 5%. Results: Surface treatment significantly affected the shear bond strengths (p

Tese de mestrado, Medicina dentaria, Universidade de Lisboa, Faculdade de Medicina Dentaria, 2014

ResumoEste estudo avaliou as fricções estática e cinética geradas por quatro tipos de arcos ortodônticos: aço inoxidável (Stainless Steel, Ormco), β-titânio (TMA, Ormco), níquel-titânio (Ni-Ti, Ormco) e β-titânio com implantação de iões (Low Friction TMA), variando a angulação de segunda ordem entre o bracket e o fio (0°, 4° e 8°). Os arcos, foram movimentados através de brackets de aço inoxidável (Mini-Diamond, Ormco) com ranhura de 0.022 polegadas. As forças de fricção foram medidas usando uma máquina universal de testes Instrom. Os dados foram submetidos a uma análise de variância factorial (3 × 4 ANOVA) seguida da comparação de médias segundo o método de Student Neuman-Keuls.A fricção foi significativamente influenciada (p

Introduction: Saliva contamination during the bonding procedure is a common cause of bracket bond failure. By combining acid and primer in one component, self-etching primers (SEP) reduce the working time and the risk of contamination. Objectives: The purpose of this study was to investigate the effect of saliva contamination of the enamel surface on the shear bond strength of orthodontic brackets cemented with two self-etching primers. Materials and Methods: One hundred orthodontic brackets were bonded to human premolars with Transbond Plus Self-etching Primer (TPSEP, 3M Unitek, Monrovia, CA) or First Step (FS, Reliance Orthodontic Products, Itasca, IL) under the following enamel surface conditions: 1) dry enamel; 2) saliva contamination/ primer; 3) saliva contamination/ air drying/ primer; 4) primer/ saliva contamination; 5) primer/ saliva contamination/ air drying/ reapplication of the primer. Samples were stored for 7 days in water at 37ºC and submitted to 500 cycles of thermal stress. Bond failure sites were classified by an Adhesive Remnant Index score system. Results:Mean shear bond strengths were significantly higher in the TPSEP groups compared to the FS groups (p < .001). For the same adhesive, no significant differences were found between the enamel surface conditions. More adhesive failures were observed in the FS groups. Conclusions: Brackets bonded with TPSEP had the highest shear bond strength values, under the different enamel surface conditions. For both SEPs, bond strengths were not significantly affected by the enamel surface conditions. The FS groups failed more frequently at the enamel / resin interface., Introdução: A contaminação salivar é uma das principais causas de insucesso na cimentação de brackets. Os selfetching primers, recentemente introduzidos em ortodontia, reduzem o tempo de execução da técnica e a probabilidade de contaminação. Objectivos: Determinar o efeito da contaminação salivar na resistência adesiva a forças de corte de brackets ortodônticos, cimentados com dois self-etching primers. Materiais e Métodos: Foram cimentados 100 brackets em premolares humanos (10 amostras por grupo), utilizando 2 adesivos (Transbond Plus e First Step) e 5 condições de superfície: 1) Condição ideal, esmalte seco; 2) Contaminação salivar antes do primer; 3) Contaminação salivar e secagem antes do primer; 4) Contaminação salivar depois do primer; 5) Contaminação salivar depois do primer, secagem e reaplicação do primer. As amostras foram armazenadas 7 dias em água a 37ºC e sujeitas a 500 ciclos de termociclagem. A área de adesão foi observada ao microscópio óptico para determinar o tipo de falha adesiva. Resultados: A análise de variância demonstrou diferenças significativas entre as forças de resistência adesiva, sendo o Transbond Plus superior ao First Step. A contaminação não influenciou significativamente a resistência adesiva. Conclusões: 1) A resistência adesiva foi mais elevada com o Transbond Plus em comparação com o First Step, independentemente da condição. 2) Para ambos os selfetching primers, a adesão não foi significativamente afectada pela presença de saliva ou pelos procedimentos de descontaminação. 3) No grupo do First Step foi encontrado um maior número de falhas adesivas na interface dente / resina composta.

ObjectiveTo evaluate the influence of light exposure time on the adhesive strength and the failure mode of orthodontic brackets bonded to human enamel.Methods100 metal brackets were bonded with Transbond XT to the enamel bucal surface of human premolars. The sample was randomly divided into 5 experimental groups (n=20) according to the light exposure time (2, 4, 6, 8 and 10s) and light cured with an LED-curing device (1600mW/cm2). The specimens were thermocycled (5–55°C, 500 cycles), stored in distilled water (37°C, 7 days) and tested in shear, using an Instron universal machine (1 KN, 1mm/min). Failure mode was classified according to the Adhesive Remnant Index (ARI) using a stereomicroscope (20× magnification). Shear bond strength (SBS) data were analyzed with one-way ANOVA, followed by Tukey post hoc tests. The failure mode data were submitted to Kruskal–Wallis nonparametric test, followed by Tukey post hoc tests to the ranks. A significance level of 5% was set for all data.ResultsThe mean SBS values were 5.5±1.93MPa (2s), 7.4±1.95MPa (4s), 8.6±1.72MPa (6s), 9.3±1.64MPa (8s) and 11.6±2.65MPa (10s). Failure mode was mainly classified as Score 2. Both the SBS (p