Nanoscale hybrid implant surfaces and Osterix-mediated osseointegration

Endosseous implant surface topography directly affects adherent cell responses following implantation. The aim of this study was to examine the impact of nanoscale topographic modification of titanium implants on Osterix gene expression since this gene has been reported as key factor for bone formation. Titanium implants with smooth and nanoscale topographies were implanted in the femurs of Osterix-Cherry mice for 1-21 days. Implant integration was evaluated using scanning electron microscopy (SEM) to evaluate cell adhesion on implant surfaces, histology, and nanotomography (NanoCT) to observe and quantify the formed bone-to-implant interface, flow cytometry to quantify of Osterix expressing cells in adjacent tissues, and real-time PCR (qPCR) to quantify the osteoinductive and osteogenic gene expression of the implant-adherent cells. SEM revealed topography-dependent adhesion of cells at early timepoints. NanoCT demonstrated greater bone formation at nanoscale implants and interfacial osteogenesis was confirmed histologically at 7 and 14 days for both smooth and nanosurface implants. Flow cytometry revealed greater numbers of Osterix positive cells in femurs implanted with nanoscale versus smooth implants. Compared to smooth surface implants, nanoscale surface adherent cells expressed higher levels of Osterix (Osx), Alkaline phosphatase (Alp), Paired related homeobox (Prx1), Dentin matrix protein 1 (Dmp1), Bone sialoprotein (Bsp), and Osteocalcin (Ocn). In conclusion, nanoscale surface implants demonstrated greater bone formation associated with higher levels of Osterix expression over the 21-day healing period with direct evidence of surface-associated gene regulation involving a nanoscale-mediated osteoinductive pathway that utilizes Osterix to direct adherent cell osteoinduction.

Análise da Resistência Flexural em Resinas à Base de Bisacrilato de Metila

Por exibir propriedades mecânicas apropriadas e um bom custo-benefício, a resina acrílica tem sido o material mais empregado para confecção de coroas provisórias. Todavia, a necessidade de um material provisório que apresente uma melhor estética,    maior resistência e maior praticidade de técnica induziram o desenvolvimento das resinas à base de bisacrilato de metila, também denominadas resinas bisacrílicas. Assim, este estudo avaliou a resistência flexural das resinas bisacrílicas Protemp 4 (3M ESPE, BRASIL) e Structur 3 (VOCO, ALEMANHA). Para isso, vinte espécimes de cada material foram confeccionados com auxílio de uma matriz metálica retangular (25 × 2 × 2 mm) e subdivididos em dois grupos (n10): (A) 7 dias de armazenagem em água destilada, e (B) - 3 meses de armazenagem em água destilada. Em seguida, cada amostra foi submetida ao teste de resistência flexural em uma Máquina de Ensaios Universal (Instron3342). Os dados obtidos foram avaliados quanto à normalidade pelo teste de Shapiro Wilk e, posteriormente, à análise de variância (ANOVA) a dois critérios e teste Tukey, todos com nível de significância de 5%. Os resultados revelaram que a resistência flexural da resina bisacrílica Protemp 4 não foi alterada (p>0.05) após 3 meses de armazenagem em água destilada. Enquanto que após esse mesmo período a resina Structur 3 apresentou redução estatisticamente significativa (p<0.05) nos valores de resistência flexural. Sendo assim, foi possível concluir que a resina bisacrílica Structur 3 SC teve sua resistência flexural diminuída após a armazenagem em água destilada.Palavras-chave: Prótese Parcial Temporária. Prótese Dentária. Restauração Dentária Temporária.

Effectiveness of LED/Laser Irradiation on In-Office Dental Bleaching after Three Years

The present in vivo randomized, triple-blinded, and split-mouth clinical study evaluated the effectiveness of a hybrid light (HL) source on the color change, stability, and tooth sensitivity in patients submitted to different in-office bleaching techniques. Twenty volunteers were divided into two groups and four subgroups. A split-mouth design was conducted to compare two in-office bleaching techniques (with and without light activation): 35% Lase Peroxide Sensy (LPS) + HL: 35% hydrogen peroxide (HP) + HL; 35% LPS: 35% HP; 25% LPS + HL: 25% HP + HL; and 35% Whiteness HP (WHP): 35% HP. For the groups activated with HL, the HP was applied on the enamel surface three consecutive times using a 3 × 2-minute protocol (three HL activations for two minutes each, with a 30-second interval for a total of seven minutes and 30 seconds) for each gel application, totaling 22 minutes and 30 seconds. For the other groups, HP was applied 3 × 15 minutes, totaling 45 minutes. A spectrophotometer was used to measure the color change (ΔE) before the treatment and 24 hours, one week, and one, 12, and 36 months after. A visual analog scale was used to evaluate the tooth sensitivity before the treatment, immediately following treatment, 24 hours, and one week after. Analysis of variance, Tukey's, Kruskall-Wallis, and Wilcoxon tests, all with α = 0.05 were performed. Statistical analysis did not reveal any significant differences (ΔE) between the in-office bleaching techniques with or without HL in the periods evaluated; the activation with HL required 50% less time to achieve such results. The groups without HL presented statistical differences for ΔE when comparing 24 hours with the other follow-up times (intergroup) and an increase in tooth sensitivity in the initial periods. All techniques and bleaching agents were effective on bleaching during a 36-month evaluation of color stability. The groups activated with HL presented lower sensitivity and required a lower activation time.