The effect of chemical and mechanical treatment of the denture base resin surface on the shear bond strenght of denture / Efeito do tratamento químico e mecânico da superfície da resina de bases de dentaduras nas forças de cisalhamento em reparos de dentaduras

OBJECTIVE: This study was aimed to evaluate the effect of three surface treatment methods on the shearbond strength of denture repairs. MATERIAL AND METHOD: 40 specimens (15 x 15 x 7mm) were fabricated according to the manufacturers’ instructions from each of three denture base materials: a heat-cured acrylic resin (VeracrilTM), a rapid-setting heat-cured acrylic resin (QC-20TM), and a pourable resin (Selecta PlusTM). The samples of each material were divided into four groups of ten. One of the groups served as a control and underwent no surface treatment. The other groups received one of three surface treatments: air blasting with 50 ìm aluminum oxide particles at 0.5 MPa pressure for 5 seconds; immersion in methyl methacrylate (MMA) for 180 seconds or immersion in acetone for 3 seconds. An autopolymerizing repair resin (Rapid RepairTM) was applied to the bonding area (6 mm in diameter, 2 mm in height) and polymerized at a pressure of two bar for 30 minutes using a pressure pot. All specimens were subjected to 10,000 thermal cycles. The shear bond strength (MPa) of the specimens was measured in a universal testing machine at a 1 mm/min crosshead speed. The effect of the mechanical and chemical treatments on the surface of the base resins wasexamined using SEM. Statistical tests used were 2 way ANOVA and Kolmogorov-Smirnov. The level ofstatistical significance was established at (p<0.05). RESULTS: There were statistically significant differencesbetween bond strength in surface treatment levels across acryl level categories (p=0.042). The results also showed differences between treatment levels (p=0.0001).Abrasive blasting significantly increased the bond strength of the repair material, but there were no significant differences between the bond strengths of the control group and the experimental groups treated with MMA or acetone. Examination by SEM revealed that chemical treatment with MMA or acetone produced a smooth surface similar...

OBJETIVO: O presente estudo foi dirigido para avaliação do efeito de três métodos de tratamento de superfície na reparação de resinas-base de dentaduras. MATERIAL E MÉTODO: 40 espécimes (15 x 15 x 7 mm) foram fabricados de acordo com as instruçõesdos fabricantes de cada um de três materiais-base de dentaduras: uma resina termopolimerizada (VeracrilTM); uma resina de termopolimerização rápida (QC-20TM) e uma resina autopolimerizável (Selecta PlusTM). Cada material foi dividido em quatro grupos de dez corpos de prova. Um dos grupos serviu como controle, não recebendo tratamento de superfície. Os outros grupos receberam três tipos de tratamento de superfície: jato abrasivocom partículas de óxido alumínio (50) com pressão de 0,5 MPa durante cinco segundos; imersão em metil metacrilato (MMA) por 180 s; imersão em acetona por três segundos. Uma resina de reparo autopolimerizável (Rapid Repair TM) foi aplicada na área de adesão (6 x 2 mm) e polimerizada sob pressão de duas atmosferas por 30 minutos, utilizando um frasco de pressão. Todos os espécimes foram sujeitos a 10.000 ciclos térmicos. A resistência às forças de cisalhamento foi medida numa máquina universal de testes a uma velocidade de 1 mm/min. O efeito do tratamento químico e mecânico das superfícies da resina base foi avaliado usando SEM. Testes estatísticos utilizados foram ANOVA e Kolmogorov-Smirnov. O nível de significância estatística foi estabelecido a p<0.05. RESULTADOS: Houve diferenças estatisticamente significantes na resistência ao cisalhamento entre as categorias de tratamento de superfície (p=0,042). Os resultados também mostraram diferenças entreníveis de tratamento (p=0,0001). O jato abrasivo aumentou significativamente a resistênciaao cisalhamento do material de reparo, mas não houve diferenças significativas entre a resistência do grupo controle e dos grupos experimentais tratados com MMA ou acetona. O exame com microscopia eletrônica demonstrou que o tratamento químico com MMA...

Effect of chemical treatment on the bioactivity of titanium / 대한치과보철학회지

STATEMENT OF PROBLEM: Titanium is widely used as an implant material for artificial teeth. Also, studies on surface treatment to form a fine passive film on the surface of commercial titanium or its alloys and improving bioactivity with bone have been carried out. However, there is insufficient data about the biocompatibility of the implant materials in the body. PURPOSE: The purpose of this study was to examine whether the precipitation of apatite on titanium metal is affected by surface modification. MATERIALS AND METHODS: Specimens chemically washed for 2 minute in a 1:1:1.5 (in vol%) mixture of 48% HF, 60% HNO3 and distilled water. Specimens were then chemically treated with a solution containing 97% H2SO4 and 30% H2O2 at 40 degrees C for 1 hour, and subsequently heat-treated at 400 degrees C for 1 hour. All specimens were immersed in the HBSS with pH 7.4 at 36.5 degrees C for 15 days, and the surface were examined with TF-XRD, SEM, EDX and XPS. Also, commercial purity Ti specimens with and without surface treatment were implanted in the abdominal connective tissue of mice for 4 weeks. Conventional aluminium and stainless steel 316L were also implanted for comparison. RESULTS AND CONCLUSIONS: The results obtained were summarized as follows. 1. An amorphous titania gel layer was formed on the titanium surface after the titanium specimen was treated with a H2SO4 and H2O2 solution. The average roughness was 2.175 micrometer after chemical surface treatment. 2. The amorphous titania was subsequently transformed into anatase by heat treatment at 400 degree C for 1 hour. 3. The average thickness of the fibrous capsule surrounding the specimens implanted in the connective tissue was 46.98 micrometer in chemically-treated Ti, and 52.20, 168.65 and 100.95 micrometer, respectively in commercial pure Ti, aluminum and stainless steel 316L without any treatment.