Physicomechanical and thermal analysis of bulk-fill and conventional composites

Abstract The aim of this study was to evaluate the degree of conversion (DC) and the thermal stability of bulk-fill and conventional composite resins. Eleven composite resin samples were prepared to evaluate the DC, Vickers microhardness (VMH), mass and residue/particle loss, glass transition temperature (Tg), enthalpy, and linear coefficient of thermal expansion (CTE) using infrared spectroscopy (FTIR), microdurometer analyses, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dilatometry (DIL). The data were subjected to statistical analysis, with a significance level of 95%. DC and VMH were not influenced by the polymerized side of the sample, and statistical differences were recorded only among the materials. Decomposition temperature, melting, and mass and residue loss were dependent on the material and on the evaluation condition (polymerized and non-polymerized). Tg values were similar between the composites, without statistically significant difference, and CTE ranged from 10.5 to 37.1 (10-6/°C), with no statistical difference between the materials. There was a moderate negative correlation between CTE and the % of load particles, by weight. Most resins had a DC above that which is reported in the literature. TGA, Tg, and CTE analyses showed the thermal behavior of the evaluated composites, providing data for future research, assisting with the choice of material for direct or semidirect restorations, and helping choose the appropriate temperature for increasing the DC of such materials.

Physicomechanical characterization and biological evaluation of bulk-fill composite resin

Abstract The aim of this study was to evaluate the cytotoxic effect, degree of conversion (% DC), Vickers hardness (VH), and surface morphology of composite resins. Eleven resins, nine bulk-fill resins, and two conventional resins were evaluated. Each material was sampled to evaluate DC (using FTIR), VH, cytotoxicity (using MTT and Neutral Red - NR test), surface morphology (using SEM and AFM), and organic filler (using EDS). All statistical tests were performed with SPSS and the level of significance was set at 0.05. MTT revealed that the materials presented low or no cytotoxic potential in relation to the control. Opus was the resin with the lowest cell viability at a 1:2 concentration at 72 h (32%) and at 7 days (43%), but that significantly increased when the NR test was applied at a 1:2 concentration after 7 days. Thickness and surface subjected to polymerization had no influence on DC, and differences were observed only between the materials. In the microhardness test, statistical differences were observed between the evaluated thicknesses. The bulk-fill resins analyzed in this study exhibited low and/or no cytotoxicity to L929 cells, except for Opus, which showed moderate cytotoxicity according to the MTT assay. When the NR test was used, results were not satisfactory for all composites, indicating the need for different methodologies to evaluate the properties of these materials. The assessed resins demonstrated acceptable physicomechanical properties.

Marginal microleakage in Bulk Fill resins / Microinfiltração marginal em resinas Bulk Fill

Introduction: Despite advances and innovations in restorative dentistry, microleakage remains one of the main problems in this area. Objective: To evaluate in vitro marginal microleakage of Bulk Fill resins in class II cavities, with cervical termination in the dentin. Material and method: Cavities, standardized on the mesial and distal surfaces, were prepared in forty top molars and randomly assigned to four groups (n = 10), according to the resin used. G1 (control): Filtek Z350 (3M/ESPE); G2: Filtek Bulk Fill flow (3M/ESPE); G3: Surefill SDR (Dentsply); G4: X-tra (Voco). These were further subdivided into subgroups according to the strategy used to apply the adhesive (self-etch technique and conventional). After storage for 24 hours in an oven (37 °C), the samples were submitted to the thermocycling test (500 cycles: 5 °C/55 °C). They were later waterproofed, immersed in Basic Fuchsin (0.5%) and sectioned in the mesial-distal direction for evaluation using a stereo magnifying glass at 40X (Coleman) Scores from 0 to 3 were assigned according to the microinfiltration observed. The Mann-Whitney and Kruskal-Wallis tests, with a significance level of 5%, were used for statistical analysis. Result: There was no statistically significant difference between the Bulk Fill resins when the total acid-etching technique was used. Only the Filtek Bulk fill flow resin presented statistically significant results when the application of the adhesive system strategy was considered, with worse results, in relation to other groups, when it the self-etching strategy was considered. Conclusion: The degree of leakage of the bulk fill resins studied, in class II cavities, was not influenced by the method of application of the adhesive system (conventional or two-step self-etching bonding agent), except for the Filtek Bulk fill flow.

Introdução: Apesar dos avanços e inovações na odontologia restauradora, a microinfiltração continua sendo um dos principais problemas nessa área. Objetivo: Avaliar in vitro a microinfiltração marginal das resinas Bulk Fill em cavidade classe II, com terminação cervical em dentina. Material e método: Cavidades padronizados na mesial e distal foram elaboradas em quarenta dentes molares superiores e alocados aleatoriamente em quatro grupos (n=10), de acordo com a resina usada: G1 (controle): Filtek Z350(3M/ESPE); G2: Filtek Bulk Fill flow (3M/ESPE); G3: Surefill SDR (Dentsply); G4: X-tra base (Voco), sendo estes subdivididos em subgrupos considerando a estratégia adesiva aplicada (autocondicionamento e convencional). Após 24h de armazenamento em estufa (37 °C), as amostras foram submetidas ao teste de termociclagem (500 ciclos: 5 ºC/55 ºC). Posteriormente foram impermeabilizados, imersos em Fucsina Básica (0,5%) e seccionados no sentido mésio-distal para avaliação com lupa estereoscópica 40X (Coleman), sendo atribuído escores de 0 a 3 de acordo com a microinfiltração observada. Para análise estatística foi aplicado o teste Mann-Whitney e o Kruskal-Wallis com nível de significância de 5%. Resultado: Não houve diferença estatística significante entre as resinas Bulk Fill, quando utilizada a técnica de condicionamento ácido total. Apenas a resina Filtek Bulk fill flow apresentou resultados estatisticamente significante quando se considerou a estrategia de aplicação do sistema adesivo, com piores resultados, em relação aos outros grupos. Conclusão: O grau de infiltração em cavidades classe II das resinas bulk fill estudadas, não foi influenciado pelo modo de aplicação do sistema adesivo (convencional ou autocondicionante), exceto para Filtek Bulk fill flow.

Intracanal pain remission in child with amelogenesis imperfecta. Case report / Remissão de dor intracanal em criança com amelogênese imperfeita. Relato de caso

ABSTRACTBACKGROUND AND OBJECTIVES:Amelogenesis imperfecta is characterized by enamel structural defects, which may severely affect dental structure in both dentitions. When accompanied by severe decay, it may impair the pulp complex requiring endodontic treatment and in case of incomplete root formation treatment becomes more complex due to pulp volume and anatomic conditions. This study aimed at reporting a clinical case of patient with amelogenesis imperfecta and with multiple incomplete root formation as a consequence.CASE REPORT:Female patient, 12 years old, leucodermic, with painful symptoms, who has looked for dental assistance. At intraoral clinical evaluation teeth presented with shape and size changes, yellowish color, covered by a thin enamel layer with roughened surface and absent in some areas, with anterior vestibular sulcus fistula and without edema. At radiographic evaluation, both dentitions were affected by the abnormality with delayed chronology of permanent teeth eruption. At the end of all evaluations, patient was diagnosed with amelogenesis imperfecta, and periodontal treatment was started, followed by endodontic treatment.CONCLUSION:Amelogenesis treatment is complex, especially when in more advanced stages of dental structure destruction. However, it is possible to reestablish patient’s functionality and esthetics with good planning and multidisciplinary approach.

RESUMOJUSTIFICATIVA E OBJETIVOS:A amelogênese imperfeita é caracterizada por defeitos estruturais do esmalte, os quais podem acometer gravemente a estrutura dentária, em ambas as dentições. Quando acometida por lesões cariosas graves, pode comprometer o complexo pulpar, necessitando de tratamento endodôntico, e em se tratando de dentes com rizogênese incompleta, o tratamento torna-se mais complexo, em virtude do volume pulpar e das condições anatômicas. O objetivo deste estudo foi relatar um caso clínico de paciente com amelogênese imperfeita e que teve como consequência múltiplos casos de rizogênese incompleta.RELATO DO CASO:Paciente do gênero feminino, 12 anos, leucoderma, com sintomas dolorosos procurou atendimento odontológico. Ao exame clinico intraoral, apresentava dentes com alteração de forma e tamanho, coloração amarelada, recobertos por uma fina camada de esmalte com superfície rugosa e em algumas áreas ausente, com fístula na região do sulco vestibular anterior e sem edema. Ao exame radiográfico ambas as dentições mostraram-se acometidas por anomalia, com retardo na cronologia de erupção dos dentes permanentes. Ao final de todos os exames, recebeu o diagnóstico de amelogênese imperfeita, dando inicio ao tratamento, que começou pelo tratamento periodontal, seguido pelo endodôntico.CONCLUSÃO:O tratamento da amelogênese é complexo, principalmente quando em estágios mais avançados de destruição da estrutura dentária. Contudo é possível restabelecer a funcionalidade e a estética do paciente quando se faz um bom planejamento do caso, com interação multidisciplinar.

Prevalência da disfunção temporomandibular e de diferentes níveis de ansiedade em estudantes universitários / Prevalence of temporomandibular joint dysfunction and different levels of anxiety among college students

JUSTIFICATIVA E OBJETIVOS: A dor orofacial tem merecido maior ênfase em saúde pública, pela sua incidência crescente, a abrangência de grupos etários cada vez mais precoces, uma associação possível com a saúde mental e as implicações na qualidade de vida dos acometidos. Esta pesquisa teve como objetivo avaliar a prevalência da disfunção temporomandibular (DTM) e dos diferentes níveis de ansiedade, em acadêmicos dos cursos de Ciências Biológicas, Educação Física, Enfermagem, Farmácia, Fisioterapia, Odontologia e Psicologia da Universidade Estadual da Paraíba. MÉTODO: Estudo transversal, com abordagem indutiva e análise estatística descritiva e inferencial com 336 acadêmicos. Para a coleta dos dados, aplicaram-se formulários contendo o Índice Anamnésico, e o Inventário de Ansiedade Traço-Estado (IDATE). Utilizaram-se os testes Qui-quadrado de Pearson e Exato de Fisher, adotando-se um intervalo de confiança de 95%. RESULTADOS: 48,2% dos indivíduos apresentavam DTM leve, 11,3% moderada e 3% grave. A DTM foi mais frequente em indivíduos solteiros, do gênero feminino, na faixa etária dos 18 aos 22 anos, com sintoma de tensão emocional. Os acadêmicos de Fisioterapia apresentaram significativamente maior necessidade de tratamento para DTM e valores mais elevados do nível de ansiedade. CONCLUSÃO: Identificou-se elevada incidência de DTM nos acadêmicos dos diversos cursos, com prevalência maior nos de Fisioterapia.

BACKGROUND AND OBJECTIVES: Orofacial pain is receiving more public health attention due to its increasing incidence, the involvement of increasingly younger age groups, its possible association to mental health and its implications on the quality of life of affected patients. This research aimed at evaluating the prevalence of temporomandibular joint dysfunction (TMJD) and of different levels of anxiety among students of Biological Sciences, Physical Education, Nursing, Pharmacy, Physical Therapy, Dentistry and Psychology of the State University of Paraíba. METHOD: Transversal study with inductive approach and descriptive and inferential statistical analysis involving 336 college students. Data were collected by the Anamnesis Index and the State-Trait Anxiety Inventory (IDATE). Pearson's Chi-square and Fisher Exact tests were used with a confidence interval of 95%. RESULTS: TMJD was mild in 48.2% of individuals, moderate in 11.3% and severe in 3%. TMJD was more frequent among single individuals, females and those between 18 and 22 years of age, with emotional stress symptoms. Physical therapy students had a significantly higher need for TMJD treatment and the highest levels of anxiety. CONCLUSION: There has been a high incidence of TMJD among college students of different courses, with higher prevalence among Physical Therapy students.