High-pressure vacuum application of TiO2 nanotubes on a polycrystalline zirconia: influence on bond strength

• Autor(a) principal: Kanashiro, Franco Naoki Mezarina
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: http://www.teses.usp.br/teses/disponiveis/25/25148/tde-04092019-200703/
• topic: Classificação; Dental ceramics; Epidemiologia; Nanotechnology; Nanotubes; Ortodontia; Terceiro molar; Titanium; Zirconia

Objective: The purpose of this study was to evaluate the microshear bond strength of resin cement to Y-TZP ceramic after different application methods of TiO2 nanotubes (nTiO2) on pre-sintered Y-TZP surfaces. Material and methods: nTiO2 were produced by alkaline synthesis, mixed with either isopropyl alcohol or acetone and applied on pre-sintered zirconia. Surface characterization with scanning electron microscopy (SEM) and energy-dispersive xray spectroscopy (EDS) analysis was executed before and after nanotubes application and after shear bond strength evaluation. Six groups were evaluated according to the application method of nTiO2 on the pre-sintered 1.4-mm-thick Y-TZP slices (n=15): 1) manual application of nTiO2 mixed with isopropyl alcohol (MAL); 2) manual application of nTiO2 nanotubes mixed with acetone (MAC); 3) application under high-pressure vacuum of nTiO2 mixed with isopropyl alcohol (HPVAl) ; 4) application under highpressure vacuum of nTiO2 mixed with acetone (HPVAc); 5) control - Al2O3 sandblasting (OX); 6) control - Rocatec silicatization (ROC). After application Y-TZP were sintered. Ceramic slices of groups 5 and 6 had their surfaces treated after sinterization. Resin composite cylinders (1.4-mm-diameter and 1-mm-height) were cemented on the ceramic slices, stored in water at 37°C for 24h and were thermalcycled for 10.000 cycles before submitting to microshear bond strength evaluation. Data were analyzed by One-way ANOVA and Newman-Keuls tests (a=.05). Results: SEM and EDS confirmed the presence of TiO2 on nTiO2-treated Y-TZP surfaces. There were significant differences between surface treatments (p<0.0001). HPVAl, OX and ROC showed higher shear bond strengths and where statistically similar (p > 0.05). MAC reached intermediary values and HPVAc and MAL presented a significant decrease in the shear bond strength, with a high percentage of premature debonding. HPVAl, OX and ROC had mixed failures (71.4%, 100%, and 92.7% respectively). MAC, HPVAc and MAL had 100% of adhesive failures. Conclusion: The high-pressure vacuum application of nTiO2 mixed with isopropyl alcohol showed the best results with shear bond strength values compared to conventional sandblasting methods.