Abstract Studies investigating the effects of different modalities of exercises on the immune system are scarce. Therefore, the aim of this study was to compare the effects of eight weeks of resistance and aerobic training on the proliferation of T and B lymphocytes from mice. Eighteen male C56BL6/J mice were divided into groups (n=6), sedentary, aerobic, and resistance training. After 8 weeks, animals were euthanized, and their splenocytes were labeled and cultured with and without stimulation. Lymphocyte proliferation (CD4+, CD8+ and CD21/CD35+) was evaluated by flow cytometry. The mice subjected to resistance exercise exhibited greater proliferation for total, CD8+ and B lymphocytes (p<0.05), but not CD4+ cells (p>0.05), compared with their sedentary counterparts. We found significant correlations between maximum load and total, CD8+ and B lymphocytes proliferation rates (p<0.05). In conclusion, our results showed that resistance training promoted an improvement in the immune response associated with CD8+ and B lymphocytes.

Abstract: Bone quality is an important issue in dentistry. Low bone density may be associated with more severe periodontitis, and may influence implant therapy success. Recent evidence suggests that physical activity can improve alveolar bone quality. Irisin is an exercise-mediated peptide that might be involved in this process. We assessed the effect of exercise and that of intra-peritoneal irisin administration on bone quality in healthy and osteoporosis-induced rodents. This study was registered at PROSPERO (CRD42020184140), and followed PRISMA guidelines. A search by two independent examiners was conducted in five databases and gray literature up to July 2021, without restrictions regarding language or date of publication. Initially, they analyzed retrieved titles and abstracts (n=3,844) based on eligibility criteria. Of this total, 19 studies remained for full-text reading, and 16 proceeded to the data extraction and quality assessment phases. Meta-analyses were conducted (n= 6 studies) to establish the effects of irisin administration on cancellous bone mineral density (BMD). Exercise or irisin administration enhanced bone quality, but the meta-analysis showed that BMD increased only slightly in osteoporotic rodents (BMD: mean difference 0.03 mg/cm3 - 95% CI 0.01-0.05). This indicates that they had no significant benefits on the bones of healthy animals. Implications of key findings evidence the potential of irisin as an agent able to mitigate bone loss caused by osteoporosis, an outcome that could favor dental rehabilitation. More studies investigating the effect of irisin on alveolar bone are needed to elucidate its therapeutic viability and implications.

Abstract: Several guidelines for dental practice have been published by dental associations and regulatory boards since the beginning of the pandemic. Initially, all non-emergency dental treatment were suspended. Healthcare personnel around the world are gradually expanding back to elective procedures. International updated recommendations alert that professionals must maintain regular observation of local health department reports, ensure personal protective equipment, and screen all patients for COVID-19 signs and symptoms. Telehealth strategies, patient screening, rescheduling when presenting COVID-19 symptoms and/or history of contact with infected people and hand/environment hygiene practices are reinforced. Appropriate cleaning and surface disinfection are mandatory. The dental staff must be trained to use appropriate Personal Protective Equipment (PPE), following a risk assessment and standard precautions: gloves; fluid resistant disposable gown, eye protection (face shield or goggles) and a medical mask. A fit tested N95 or KN95 respirator (or higher) is recommended when aerosol generating procedures are performed. Only essential accompanying persons should attend to dental appointment with the patient and must wear a cloth face covering or facemask. Social distancing and mask wearing by all staff are necessary in all areas of the office. Dental health care providers should keep up to date to the current guidance of clinical practice during the pandemic.

The expansion of coronavirus disease 2019 (COVID-19) throughout the world has alarmed all health professionals. Especially in dentistry, there is a growing concern due to it’s high virulence and routes of transmission through saliva aerosols. The virus keeps viable on air for at least 3 hours and on plastic and stainless-steel surfaces up to 72 hours. In this sense, dental offices, both in the public and private sectors, are high-risk settings of cross infection among patients, dentists and health professionals in the clinical environment (including hospital’s intensive dental care facilities). This manuscript aims to compile current available evidence on prevention strategies for dental professionals. Besides, we briefly describe promising treatment strategies recognized until this moment. The purpose is to clarify dental practitioners about the virus history and microbiology, besides guiding on how to proceed during emergency consultations based on international documents. Dentists should consider that a substantial number of individuals (including children) who do not show any signs and symptoms of COVID-19 may be infected and can disseminate the virus. Currently, there is no effective treatment and fast diagnosis is still a challenge. All elective dental treatments and non-essential procedures should be postponed, keeping only urgent and emergency visits to the dental office. The use of teledentistry (phone calls, text messages) is a very promising tool to keep contact with the patient without being at risk of infection.

Abstract The aim of this study was to evaluate the association of malocclusion, nutritive and non-nutritive sucking habits and dental caries in the masticatory function of preschool children. A cross-sectional study was conducted with a sample of 384 children aged 3–5 years. A single examiner calibrated for oral clinical examinations performed all the evaluations (kappa > 0.82). Presence of malocclusion was recorded using Foster and Hamilton criteria. The number of masticatory units and of posterior teeth cavitated by dental caries was also recorded. The parents answered a questionnaire in the form of an interview, addressing questions about the child’s nutritive and non-nutritive sucking habits. The masticatory function was evaluated using Optocal test material, and was based on the median particle size in the masticatory performance, on the swallowing threshold, and on the number of masticatory cycles during the swallowing threshold. Data analysis involved simple and multiple linear regression analyses, and the confidence level adopted was 95%. The sample consisted of 206 children in the malocclusion group and 178 in the non-malocclusion group. In the multiple regression analysis, the masticatory performance was associated with age (p = 0.025), bottle feeding (p = 0.004), presence of malocclusion (p = 0.048) and number of cavitated posterior teeth (p = 0.030). The swallowing threshold was associated with age (p = 0.025), bottle feeding (p = 0.001) and posterior malocclusion (p = 0.017). The number of masticatory cycles during the swallowing threshold was associated with the number of cavitated posterior teeth (p = 0.001). In conclusion, posterior malocclusion, bottle feeding and dental caries may interfere in the masticatory function of preschool children.

Abstract The expansion of coronavirus disease 2019 (COVID-19) throughout the world has alarmed all health professionals. Especially in dentistry, there is a growing concern due to it’s high virulence and routes of transmission through saliva aerosols. The virus keeps viable on air for at least 3 hours and on plastic and stainless-steel surfaces up to 72 hours. In this sense, dental offices, both in the public and private sectors, are high-risk settings of cross infection among patients, dentists and health professionals in the clinical environment (including hospital’s intensive dental care facilities). This manuscript aims to compile current available evidence on prevention strategies for dental professionals. Besides, we briefly describe promising treatment strategies recognized until this moment. The purpose is to clarify dental practitioners about the virus history and microbiology, besides guiding on how to proceed during emergency consultations based on international documents. Dentists should consider that a substantial number of individuals (including children) who do not show any signs and symptoms of COVID-19 may be infected and can disseminate the virus. Currently, there is no effective treatment and fast diagnosis is still a challenge. All elective dental treatments and non-essential procedures should be postponed, keeping only urgent and emergency visits to the dental office. The use of teledentistry (phone calls, text messages) is a very promising tool to keep contact with the patient without being at risk of infection.

Abstract This study aimed to evaluate if the addition of chlorogenic acid (ChA) to semen extenders improves the quality of cooled boar semen processed in Percoll. The experimental design was randomized blocks (ejaculates) in a 2×3 factorial (with or without Percoll, and three antioxidant systems: a negative control, without supplementation, a positive control – vitamin E, and ChA), totaling six treatments and 12 repetitions. ChA and vitamin E (VE) were added at 4.5 mg/ml and 400 μg/ml in extender, respectively. At 0, 48 and 72h of storage at 15ºC, 80 ml insemination doses each containing 2.0 billion sperm cells were submitted to centrifugation in Percoll. The use of Percoll impaired (P<0.01) all motility patterns but decreased (P<0.01) the number of abnormal cells at 0, 48 and 72h of storage. Both VE and ChA improved (P<0.05) the total motility after Percoll processing, but only in semen stored for 48h. The same effect was not observed (P>0.05) in semen stored for 72h. ChA improved (P<0.05) the total motility of the semen stored for 72h, but this effect was not observed (P>0.05) when the semen was processed in Percoll. The antioxidants had no effect (P>0.05) on the viability and integrity of the acrosome, but ChA reduced (P<0.05) the number of abnormal cells at 0h, while VE increased the number of abnormal cells in semen stored for 72h, independent of the use of Percoll. There was no effect (P>0.05) of antioxidants or Percoll on the concentration of malondialdehyde in seminal plasma. The use of Percoll had no effect (P>0.05) on the cholesterol efflux, but ChA increased (P<0.05) this parameter at 0h and reduced (P<0.05) in the semen stored for 72h not processed with Percoll. In conclusion, the addition of ChA to semen extenders improved the quality of boar semen processed or not in Percoll.

ABSTRACT The objective of this study was to evaluate the putative effects of the use of coffee husk as floor covering on boar semen quality. Sixteen boars were divided into two groups. The first group was held in a conventional system with a compact floor. The second group was kept on a compact floor covered with coffee pods. The experimental period was 60 days. Levels of caffeine and chlorogenic acid in the insemination doses (ID) before and after 96 h of storage at 15 °C and the reproductive performance (litter size and rate of return to estrus) of these doses after their utilization in a standard artificial insemination protocol were evaluated. The ID from the animals kept in pens containing the coffee pods contained 25.4±8.7 µg/mL of caffeine, whereas no significant amounts of chlorogenic acid were detected. Semen from boars housed with coffee husk showed a significant increase in malondialdehyde levels, which indicates a significant increase in cell membrane peroxidation, after 96 h of storage. There were no significant differences in the other evaluated semen quality parameters when analyzed among groups. Likewise, there was no significant influence of coffee hulls on either the rate of return to estrus or the litter size of inseminated females. The use of coffee husks as floor covering worsens the quality of fresh semen and that of insemination doses stored for 96 h but not the quality of semen immediately diluted; therefore, coffee husks may be used only on farms that use semen immediately processed after collection without affecting the reproductive parameters of breeding stock.

Introduction: beta-glucans (BG) derived from plant tissues are reported to show metabolic effects. In contrast, those fibers isolated from yeast seem to be more related to immune response modulation. Since diabetic individuals are more susceptible to exacerbation of inflammatory signs, the ingestion of fibers that could conjugate both metabolic and immune effects would be of great importance. Objective: we investigated the effect of BG - Saccharomyses cerevisae - ingestion on glycemic and lipoprotein profile of diabetic rats. Design: twenty-four adult Wistar rats were used, distributed into 4 groups in a design of entirely casualized delineation with a 2 x 2 factorial model (with and without diabetes; with and without BG). Diabetes Mellitus was induced by an intraperitoneal injection of 80mg/kg of strepzotocin. Thus, animals with fasting glycemia of over 250 mg/dl were considered diabetic. Forty-eight hours after induction, the rats received daily doses of 30 mg/kg of BG or saline solution by gavage during 28 days. Results and discussion: the Groups with DM presented a higher glycemic index and lower C peptide levels than the control groups, in addition to lower weight gain and higher ration consumption, water ingestion and urinary volume. Total cholesterol levels (CT), LDL-C + VLDL-C, plasma triacylglycerides (TAG) and alanine aminotransferase (ALT) were also higher in the diabetic animals (p < 0.05), and there were no alterations in the HDL-C levels. The ingestion of BG reduced blood glucose concentrations (30%), TAG (32%) and ALT (41%) (p < 0.05). No histopathological hepatic alterations were observed in any of the groups. Furthermore, the diabetic animals present increase in villous:crypt ratio (V:C) in the duodenum, without interference of BG. No alterations in the carcass were observed between the groups. Conclusion: it was concluded that the use of BG significantly reduced the glycemic, TAG and ALT levels, showing its therapeutic potential.

Introducción: los beta-glucanos (BG) derivados de tejidos vegetales se ha informado que muestran efectos metabólicos. Por el contrario, esas fibras aisladas de levadura parecen estar más relacionadas con la modulación de la respuesta inmune. Dado que los individuos con diabetes son más susceptibles a la exacerbación de los signos inflamatorios, la ingestión de fibras sí podría conjugar ambos efectos metabólicos e inmunológicos, lo cual sería de gran importancia. Objetivo: el objetivo de este estudio fue investigar los efectos de la ingestión de los BG -Saccharomyses cerevisiae- en el perfil glucémico y la lipoproteína de ratas diabéticas. Metodos: en el diseño de delineación, totalmente precario, fueron utilizadas 24 ratas Wistar macho adultas distribuidas en cuatro grupos, con un modelo factorial 2 x 2 (con y sin diabetes, con y sin BG). La diabetes mellitus fue inducida por la inyección intraperitoneal de un 80 mg/kg de estrepzotocina. Por lo tanto, los animales con glucemia en ayunas de más de 250 mg/dl fueron considerados diabéticos. Cuarenta y ocho horas después de la inducción, las ratas recibieron dosis diarias de 30 mg/kg de BG o solución salina mediante alimentación forzada durante 28 días. Resultados y discusión: los grupos con DM presentó el mayor índice glucémico y menores niveles de péptido C que los grupos de control, además de reducir el aumento de peso y un mayor consumo de la ración, la ingestión de agua y el volumen urinario. Los niveles de colesterol total (CT), LDL-C + VLDL-C, triacilglicéridos plasmáticos (TAG) y alanina aminotransferasa (ALT) también fueron más altos en los animales diabéticos (p < 0,05), y había alteraciones en los niveles de HDL-C. La ingestión de BG redujo las concentraciones de glucosa en sangre (30%), TAG (32%) y ALT (41%) (p < 0.05). No se observaron alteraciones hepáticas en ninguno de los grupos. Además, los animales diabéticos presentaron un aumento de la relación cripta:vellosidades (V:C) en el duodeno, sin interferencia de BG. No se observaron alteraciones en la carcasa entre los grupos. Discusión: se concluyó que el uso de BG redujo significativamente la glucemia, los niveles de TAG Y ALT, mostrando su potencial terapéutico.

This study aimed at evaluating the effect of ractopamine (RAC) on metabolism, zootechnical performance, body composition, and behavior in Wistar rats submitted to acute and chronic restrain stress. The oral dose of 5 mg/kg of RAC was administered in periods of 0, 7, 14, 21, and 28 days. The elevated plus-maze test (EPMT) was used for behavioral assessment. Blood, carcass and viscera characteristics were evaluated. Insulin-dependent glucose transporters (GLUT-4) were semi-quantified by Western Blot in epididymal adipocytes. RAC periods associated with chronic stress increased the GLUT-4 protein expression in adipose tissue in a time-dependent manner (P=0.01), i.e., the longer the RAC addition period, the higher the GLUT-4 concentration in chronically stressed animals (0=1.42; 7=1.19; 14=2.03; 21=1.59; 28=2.35). The stress periods combined with RAC increased the time spent in the opened arms of the maze (Chronic stress: 0=10.6; 7=8.7; 14=5.9; 21=12.3; 28=4.0; Acute stress 0=3.1; 7= 4.7; 14=7.5; 21=0.0; 28=2.8) (P=0.04). Chronic (entries on the closed arms [ECA]=3.60) and acute (ECA=3.80) stress reduced locomotive activity in the maze (P=0.03). The results suggested that stress could negatively affect the possible benefits offered by the RAC, mainly impairing the adipose tissue metabolism and behavior in the animals.

Introduction: Functional foods have been widely utilized to reduce the symptoms of various diseases such as diabetes mellitus (DM). Among the foods used to combat these effects are soluble fibres, mainly those rich in beta-glucans (BGs). Objective: To review the effects of beta-glucans (BGs) on glucose plasmatic levels of diabetic individuals. Design: A search was conducted using the Pubmed, Science Direct and Scielo databases using the keywords: diabetes mellitus and beta-glucan and glucose and glycaemia. As inclusion criteria, only studies on diabetic human individuals (type 1 or type 2) who consumed BGs were selected. Results and Discussion: Of the 819 initial articles retrieved, only 10 fit the inclusion criteria and were used in the study. It was observed that doses around 6.0g/person/ day, for at least 4 weeks were sufficient to provoke improvements in the blood glucose levels and also lipid parameters of individuals with DM. However, glucose levels do not reach normal levels using BG alone. Low doses of BG for at least 12 weeks were also reported to promote metabolic benefits. Conclusions: Based on previous research, it was concluded that the ingestion of BGs was efficient in decreasing glucose levels of diabetic patients. The consumption of greater doses or smaller doses for longer periods of time produced better results.

Introducción: Alimentos funcionales han sido ampliamente utilizados para reducir los síntomas de diversas enfermedades como la diabetes mellitus (DM). Entre los alimentos utilizados en el combate de estos efectos, están las fibras solubles, principalmente aquellas que tienen buena cantidad de beta-glucano (BG’s). Objetivo: El objetivo de esta revisión sistemática fue evaluar los efectos de los BG´s en los parámetros metabólicos de individuos diabéticos. Métodos: Fue conducida una búsqueda en las bases de datos Pubmed, ScienceDirect y cielo, utilizando las siguientes palabras-clave: diabetes mellitus and beta- glucano and glucosa and glucemia. Como criterio de inclusión, fueron seleccionados solamente estudios en individuos diabéticos (tipo 1 o tipo 2) que consumieron BG´s. Resultados y Discusión: De los 819 trabajos inicialmente encontrados, 10 artículos se encuadraron en los criterios de inclusión, y por eso fueran utilizados en el estudio. Fue observado que dosis superiores de 6,0 g/ individuo/día, o dosis más grandes que 3,0 g/individuo/ día por un periodo de tiempo más largo, son suficientes para provocar mejoras en los parámetros glucémicos y lipidicos de portadores de DM. Bajas dosis de BG por al menos 12 semanas también presentaron efectos metabólicos benéficos. Conclusión: Tomando en cuenta los resultados observados, se concluye que los BG´s son eficientes en la atenuación de los efectos indeseables del DM, siendo las dosis más grandes o el consumo de pequeñas cantidades por un tiempo más largo las que promueven resultados mejores.

Emulsões múltiplas têm sido reconhecidas como uma nova tecnologia para as indústrias de alimentos. Devido a sua estrutura diferenciada dos demais sistemas coloidais, ou seja, existência de duas fases dispersas, esse grupo de emulsão apresenta vantagens em relação às emulsões convencionais, principalmente, no que se refere ao encapsulamento, à proteção e à liberação controlada de componentes bioativos. Assim, a estabilidade e a biodisponibilidade dos encapsulados podem ser aumentadas ou otimizadas, fato que possibilita o planejamento de melhores resultados pela indústria, por meio da produção de novos alimentos. Ainda, com a perspectiva de aumentar o valor nutricional de muitos alimentos industrializados, infere-se uma maior contribuição deles para a promoção da saúde e para prevenção e tratamento de certas doenças crônico-degenerativas. A presente revisão apresenta as bases da tecnologia usual de elaboração de emulsão múltipla, os principais processos de instabilidade a que esse sistema está susceptível, e a aplicação de emulsões múltiplas como sistemas encapsuladores e transportadores de componentes bioativos.

Multiple emulsions have been recognized as a new technology for the food industry. Due to their different structure from other colloidal systems, namely the existence of two dispersed phases, this group of emulsion has advantages over conventional emulsions, especially with regard to packaging, protection and controlled release of bioactive components. Thus, the stability and bioavailability of encapsulated may be increased or optimized, a fact that enables the planning of better results by the industry through the production of new foods. Also, the prospect of increasing the nutritional value of many processed foods, infers greater contribution to the promotion of health and prevention and treatment of certain chronic diseases. This review presents the bases of the usual technology of preparation of multiple emulsion, the main processes of instability that this system is susceptible, and the application of multiple emulsions as encapsulating systems and carriers of bioactive components.

The aims of the present study were to compare aspects related to malocclusion between individuals with Down syndrome (DS) and a control group, establish malocclusion severity, and identify determinant factors. A total of 120 individuals (60 with DS and 60 with no physical or mental impairment), were included in the study. Data were collected through interviews, analyses of the medical charts, and oral examinations. The criteria of the Dental Aesthetic Index were used for the diagnosis of malocclusion. Chi-square test (p ≤ 0.05) and multivariate logistic regression were used for comparisons between the two groups and to determine the association between the dependent (malocclusion severity) and independent variables. Statistically significant differences were found between the two groups for the following variables: missing teeth, diastema, overjet, mandibular protrusion, anterior open bite, posterior crossbite, facial type, lip incompetence, and Angle classification. DS, a history of premature birth, and long face pattern were found to be associated with malocclusion severity. Individuals with DS exhibited more occlusal problems than those in the control group.

Neste trabalho, a otimização do processo de formação de complexos interpoliméricos entre lactoalbumina e os polissacarídeos goma xantana e pectina foi estudada a fim de definir as condições ótimas para a formação dos complexos. Para o planejamento experimental foi utilizada a metodologia de superfície de resposta (MSR) para três variáveis independentes. As condições ótimas para a formação dos complexos entre lactoalbumina e goma xantana foi: pH 6,6, concentração de NaCl de 0,6 mol/L e concentração de goma xantana 0,083% m/v. E para os complexos formados entre lactoalbumina e pectina foram: pH 6,6, concentração de NaCl 0,25 mol/L e concentração de pectina, 0,113% m/v. O modelo matemático que melhor se ajustou aos dados experimentais foi o correspondente ao complexo goma xantana-lactalbumina, cujo coeficiente de determinação (R²) foi de 0,97.

In this work, the optimization process of interpolymeric complexes formation between lactalbumin and the polysaccharides xanthan gum and pectin was studied in order to define the optimum conditions for the complexes formation. For the experimental design, response surface methodology (RSM) for three independent variables was used. The optimum conditions for the complexes formation between lactalbumin and xanthan gum were: pH 6.6, NaCl concentration of 0.6 mol/L and xanthan gum concentration 0.083% w/v. And for the complexes formed between pectin and lactalbumin the conditions were: pH 6.6, NaCl concentration of 0.25 mol/L and pectin concentration of 0.113% w/v. The best fitted model for the experimental data was that corresponding to the complex xanthan gum-lactalbumin, whose coefficient of determination (R²) was 0.97.

OBJETIVO: investigar os fatores determinantes do desconforto atribuído ao uso do aparelho ortodôntico fixo e sua influência na qualidade de vida de adolescentes. MÉTODOS: participaram desse estudo transversal 272 indivíduos, com idades entre 9 e 18 anos, estudantes de escolas públicas e privadas, que usavam aparelhos ortodônticos fixos (braquetes). Os participantes foram selecionados aleatoriamente, entre 62.496 indivíduos da mesma faixa etária. A coleta de dados foi feita em forma de entrevista e questionário. A intensidade do desconforto e variáveis biopsicossociais foram avaliadas por meio do Oral Impact on Daily Performance (OIDP). A autoestima foi determinada pela Global Negative Self-Evaluation (GSE). A análise estatística envolveu o teste qui-quadrado e a análise de regressão de Poisson, simples e múltipla. RESULTADOS: embora a maioria dos indivíduos não apresentasse desconforto, observou-se uma prevalência de impacto na vida diária devido, exclusivamente, ao uso do aparelho ortodôntico fixo, de 15,9%. Variáveis idade de 15 a 18 anos [RP = 3,2 (IC 95% = 1,2-8,5)], dificuldade de falar [RP = 2,2 (IC 95% = 1,1-4,6)], dificuldade de limpar a boca [RP = 2,4 (IC95% = 1,2-4,8)] e mobilidade dos dentes [RP = 3,9 (IC 95% = 1,8-8,1)] permaneceram associadas, de forma independente, à maior prevalência de desconforto (p ≤ 05). CONCLUSÕES: desconforto associado ao uso de aparelhos ortodônticos fixos influenciou negativamente a qualidade de vida de adolescentes. Os fatores determinantes foram idade, dificuldade de limpar a boca, de falar e mobilidade dentária.

OBJECTIVE: To investigate the determinant factors of discomfort attributed to the use of fixed orthodontic appliance and the effect on the quality of life of adolescents. MATERIAL AND METHODS : Two hundred and seventy-two individuals aged between 9 and 18 years old, enrolled in public and private schools and undergoing orthodontic treatment with fixed appliance participated in this cross-sectional study. The participants were randomly selected from a sample comprising 62,496 individuals of the same age group. Data was collected by means of questionnaires and an interview. Discomfort intensity and bio-psychosocial variables were assessed using the Oral Impact on Daily Performance questionnaire. Self-esteem was determined using the Global Negative Self-Evaluation questionnaire. Statistical analysis involved the chi-square test and both simple and multiple Poisson regression analyses. RESULTS: Although most individuals did not present discomfort, there was a prevalence of 15.9% of impact on individuals' daily life exclusively due to the use of fixed orthodontic appliance . Age [PR: 3.2 (95% CI: 1.2-8.5)], speech impairment [PR: 2.2 (95% CI: 1.1-4.6)], poor oral hygiene [PR: 2.4 (95% CI: 1.2-4.8)] and tooth mobility [PR: 3.9 (95% CI: 1.8-8.1)] remained independently associated with a greater prevalence of discomfort (P ≤ 0.05). CONCLUSIONS: Discomfort associated with the use of fixed orthodontic appliances exerted a negative influence on the quality of life of the adolescents comprising the present study. The determinants of this association were age, poor oral hygiene, speech impairment and tooth mobility.