Surface properties and flexural fatigue strength of an advanced lithium disilicate.

The aim of this study was to evaluate the surface properties and fatigue mechanical behavior of an advanced lithium disilicate ceramic in comparison to lithium disilicate and zirconia. First, discs (n = 15, diameter = 13.5 mm and thickness = 1.2 mm) were made from the following materials: 4Y-PSZ - 4% mol yttria-stabilized zirconia (IPS e.max ZirCAD A2); LD - lithium disilicate (IPS e.max CAD); ALD - advanced lithium disilicate (CEREC Tessera). The specimens were crystalized/sintered and subsequently analyzed by a rugosimeter (Mitutoyo SJ-410) to determine surface roughness (parameters Ra and Rz). Specimens were subjected to biaxial flexural fatigue testing using the step-test method (20 Hz; 10,000 cycles per step; initial stress of 200 MPa; and step size of 25 MPa) until specimen fracture. Statistical analyses included Shapiro-Wilk, Kruskal-Wallis, and post-hoc tests for roughness data, while survival analysis (Kaplan-Meier and Mantel-Cox) and reliability analysis (Weibull modulus) were applied to flexural fatigue strength data. Hardness (Vickers) results were submitted to analysis of variance (1-way ANOVA) and Tukey's test. Zirconia (4Y-PSZ) showed higher FFS, CFF (467 MPa and 115216 cycles) and survival compared to the other materials. ALD had the lowest FFS, CFF (215 MPa and 11,908 cycles) and survival. ALD showed lower Weibull modulus (m = 6.63 for FFS; m = 1.27 for CFF) than LD for FFS (m = 17.33), and lower than LD (m = 4.64) and 4Y-PSZ (m = 6.69) for CFF. ALD showed the lowest Ra (0.07 µm) and Rz (1.05 µm) values, while 4Y-PSZ (Ra = 0.22 µm; Rz = 1.91 µm) and LD (Ra = 0.21 µm; Rz = 2.17 µm) showed higher and similar values. Zirconia (4-YPSZ) was the hardest material, while lithia-based ceramics (LD and ALD) presented the lowest and similar hardness values. Fractures originated in surface defects in the tensile stress concentration region. ALD has lower flexural fatigue strength compared to the other tested materials, along with higher variability (lower structural reliability).

Advanced lithium disilicate: A comparative evaluation of translucency and fatigue failure load to other ceramics for monolithic restorations.

The aim of this in vitro study was to evaluate the surface roughness, translucency, fatigue failure load (FFL), and number of cycles for fatigue failure (CFF) of a recently released lithia-based material called advanced lithium disilicate and three other ceramics indicated for monolithic restorations. First, ALD (advanced lithium disilicate, CEREC Tessera, Dentsply Sirona), LD (lithium disilicate, IPS e. max CAD, Ivoclar), LS (lithium silicate-disilicate, Suprinity, Vita Zahnfabrik), and 4Y-PSZ (Yttria-stabilized zirconia, IPS e.max ZirCAD MT, Ivoclar) discs (n = 15, Ø = 10 mm and thickness = 1.0 mm) were fabricated from CAD/CAM blocks/discs, A2 shade. The discs were sintered/crystallized and subsequently analyzed by a rugosimeter (Mitutoyo SJ-410) to determine Ra and Rz surface roughness parameters. Next, they were evaluated to determine the translucency parameter (TP) using a bench-top spectrophotometer (SP60, EX-Rite). The discs were subsequently cemented to glass fiber epoxy resin discs, and the specimens were tested under cyclic loading (Step-test), immersed in distilled water at a frequency of 20 Hz, with an initial cyclic load of 200 N for 5,000 cycles and increments of 50 N every 10,000 cycles until failure. Fatigue failure load (FFL) and number of cycles for fatigue failure (CFF) were recorded for subsequent Kaplan Meier analysis, with post-hoc Mantel-Cox and Weibull analysis (α = 0.05). Complementary fractographic, topographic and energy dispersive spectroscopy analyses (EDS) were performed. 4Y-PSZ showed higher survival (p < 0.05), with higher FFL and CFF (1077 N; 180,333 cycles), followed by LD (980 N; 161,000 cycles), LS (937 N; 152,333 cycles) and ALD (910 N; 147,000 cycles). No differences were observed between the tested groups regarding Weibull modulus. ALD presented TP (28.14) equal to DL (28.27) and higher than LS (25.51). All lithia-based materials had higher translucency than 4Y-PSZ (TP = 8.62) (p < 0.05). ALD appears to have a similar elemental composition to LD and LSD for oxygen and silicon. ALD and LSD have a similar zirconium content. Fractures originated on the cemented surface of the ceramic discs. Lithia-based ceramics showed lower surface roughness, with ALD (Ra = 0.04 µm; Rz = 0.66 µm) showing the lowest values (p < 0.05). Despite showing lower FFL when compared to LD and 4Y-PSZ, ALD has compatible translucency and mechanical fatigue performance with its indication for fabricating monolithic, anterior and posterior adhesively cemented single-unit restorations. However, further studies are needed to substantiate its clinical performance.

Perfil dos usuários e necessidades odontológicas dos pacientes atendidos nas clínicas odontológicas da Universidade Franciscana ­ Santa Maria, RS / Users profile and dental needs of patients attending the dentistry clinics of Universidade Franciscana ­ Santa Maria, RS

Objetivo: o modelo de uso de serviços de saúde de um determinado grupo populacional é, em grande parte, explicadopor seu perfil de necessidades em saúde. O conhecimento deste é importante para estabelecer o modocomo a atenção odontológica será ofertada. Métodos: realizou-se um estudo retrospectivo a partir de dados secundários(prontuários) (n=381) de pacientes atendidos nas clínicas odontológicas da Universidade Franciscana(UFN) de Santa Maria, RS. Os dados deste estudo foram obtidos através da análise dos prontuários de pacientesatendidos nas clínicas odontológicas da UFN entre os anos de 2005 e 2019. Apenas prontuários com a assinaturado paciente ou responsável foram inseridos neste trabalho. Para a obtenção dos dados, foi construído uminstrumento de coleta, sendo obtidas informações sociodemográficas (idade, sexo, cor, estado civil, profissão elocal de residência) e sobre o estado de saúde (doenças sistêmicas, uso de medicação, perfil de saúde bucal eCPO-D). Cada sujeito selecionado recebeu uma codificação que garantiu seu anonimato. A análise estatísticafoi do tipo descritiva e foi realizada em software estatístico. Resultados: a maioria dos pacientes atendidos erado sexo feminino (68,5%), sendo que a faixa etária mais prevalente foi entre 31 e 50 anos (44,5%). A maioriados pacientes eram estudantes (20,3%), seguidos de trabalhadores do lar (10,9%) e aposentados (7,8%).A queixa principal mais reportada foi a dor de dente (25,2%). Nos resultados deste trabalho, a presença dedoença preexistente foi reportada por 87 (22,8%) pacientes, sendo todas classificadas como doenças crônicas,de acordo com a classificação proposta por Murow e Oglesby13 (1996); a mais prevalente foi problemas alérgicos,69 (18,1%), seguidos por problemas respiratórios, 42 (11%), e problemas gástricos, 39 (10%). A utilizaçãode medicação de uso contínuo foi relatada por 150 (39,3%) pacientes. Conclusão: os pacientes das clínicasodontológicas da UFN de Santa Maria, RS, são, em sua maioria, estudantes, aposentados e trabalhadores do lar,sendo a dor e a fratura dentária as principais queixas dos usuários. Dessa maneira, acredita-se que os discentesda instituição devem estar aptos a realizarem atendimentos de caráter emergencial. O conhecimento do manejoodontológico de pacientes com doenças crônicas não transmissíveis deve ser uma preocupação para daquialguns anos, visto que o envelhecimento da população é esperado para os próximos 30 anos.(AU)

Objective: the health services use model of a given population group is largely explained by its profile of health needs. The knowledge of this is important to establish how dental care will be offered. Methods: in view of this, a retrospective study was carried out using secondary data (medical records) (n = 381) of patients seen at the dental clinics at the Franciscana University (UFN) in Santa Maria, RS. The data of this study were obtained through the analysis of the medical records of patients seen at dental clinics at Universidade Franciscana, between the years 2005 and 2019. Only medical records with the signature of the patient or guardian were included in this work. To obtain the data, an instrument for collecting and collecting sociodemographic information (age, sex, color, marital status, profession and place of residence) and health status (systemic diseases, use of medication, oral health profile and CPO-D) were obtained. Each selected subject received a code that guaranteed their anonymity. The statistical analysis was descriptive and was performed using statistical software. Results: most of the patients seen were female (68.5%), with the most prevalent age group between 31 and 50 years old (44.5%). Most patients were students (20.3%), followed by household workers (10.9%) and retired (7.8%). The main complaint most reported was toothache (25.2%). In the results of this study, the presence of pre-existing disease was reported by 87 (22.8%) patients, all of whom were classified as chronic diseases, according to the classification proposed by Murow and Oglesby13 (1996). The most prevalent were allergic problems, 69 (18.1%), followed by respiratory problems, 42 (11%), and gastric problems, 39 (10%). The use of medication for continuous use was reported by 150 (39.3%) patients. Conclusion: patients at dental clinics at UFN in Santa Maria / RS are mostly students, retirees and home workers, with dental pain and fracture being the main complaints of users. Thus, it is believed that the institution's students must be able to provide emergency care. Knowledge of the dental management of patients with chronic non-communicable diseases should be a concern for some years to come, since the aging of the population is expected for the next 30 years.(AU)