RESUMO
The topography and chemical composition modification of titanium (Ti) implants play a decisive role in improving biocompatibility and bioactivity, accelerating osseointegration, and, thus, determining clinical success. In spite of the development of surface modification strategies, bacterial contamination is a common cause of failure. The use of systemic antibiotic therapy does not guarantee action at the contaminated site. In this work, we proposed a surface treatment for Ti implants that aim to improve their osseointegration and reduce bacterial colonization in surgery sites due to the local release of antibiotic. The Ti discs were hydrothermally treated with 3M NaOH solution to form a nanostructured layer of titanate on the Ti surface. Metronidazole was impregnated on these nanostructured surfaces to enable its local release. The samples were coated with poly(vinyl alcohol)-PVA films with different thickness to evaluate a possible control of drug release. Gamma irradiation was used to crosslink the polymer chains to achieve hydrogel layer formation and to sterilize the samples. The samples were characterized by XRD, SEM, FTIR, contact angle measurements, "in vitro" bioactivity, and drug release analysis. The alkaline hydrothermal treatment successfully produced intertwined, web-like nanostructures on the Ti surface, providing wettability and bioactivity to the Ti samples (Ti + TTNT samples). Metronidazole was successfully loaded and released from the Ti + TTNT samples coated or not with PVA. Although the polymeric film acted as a physical barrier to drug delivery, all groups reached the minimum inhibitory concentration for anaerobic bacteria. Thus, the surface modification method presented is a potential approach to improve the osseointegration of Ti implants and to associate local drug delivery with dental implants, preventing early infections and bone failure.
RESUMO
This study aimed to evaluate the influence of the association of different adhesive systems with a silorane-based resin composite on the microleakage of class V cavities. Fifteen premolars were freshly extracted and randomly divided into three experimental groups, according to the adhesive system used, as follows: P-90: Filtek P-90 adhesive; SE PLUS: Adper SE Bond adhesive; and SBMP: Adper Scotchbond Multi-Purpose adhesive. Class V cavities were constructed on the buccal and lingual surface of each premolar exhibiting enamel margin at the oclusal surface and dentine margin at the cervical surface. The cavities were filled with a silorane-based resin composite (Filtek P90 Silorane Low Shrink Restorative, 3M ESPE). After 24 hours of water storage at 37 ºC, the restoration were finished and polished. The teeth were water sealed, immersed in 50% silver nitrate for 24 hours, followed by immersion in a radiographic developing solution for 2 hours. The samples were cut and the degree of dye penetration was assessed with the aid of stereoscopic loupe at x20 magnification, through a 4-point score system (0 to 3).The mean microleakage values were: P-90 = 23.48; SE PLUS = 31.13; and SBMP = 36.90. The results were submitted Kruskal-Wallis and Mann-Whitney tests, showing statistically significant differences among groups (p ≤ 0.05). P-90 showed significant difference when compared to SBMP, exhibiting the smallest scores of dye penetration.The association of different adhesive systems with the silorane-based resin composite (Filtek P-90) influenced on the microleakage degree.
O objetivo deste estudo foi avaliar a influência da associação de diferentes sistemas adesivos a um compósito à base de silorano na microinfiltração de cavidades Classe V. Quinze pré-molares recém-extraídos e divididos aleatoriamente em três grupos experimentais, de acordo com o sistema adesivo empregado, sendo: P-90: Adesivo Filtek P-90; SE PLUS: Adesivo Adper SE Bond; e SBMP: Adesivo Adper Scotchbond Multi-Uso. As cavidades de classe V foram confeccionadas nas faces vestibular e lingual de cada pré-molar com margem oclusal em esmalte e cervical em dentina. As cavidades foram restauradas com um compósito a base de silorano (Filtek P90 Silorane Low Shrink Restorative, 3M ESPE). Após 24 horas de armazenamento em água a 37 ºC, as restaurações receberam acabamento e polimento. Os dentes foram impermeabilizados, imersos em nitrato de prata a 50% por 24 horas e, posteriormente, em solução reveladora de radiografias por 2 horas. As amostras foram seccionadas e o grau de penetração do corante foi avaliado por meio de uma lupa estereoscópica com 20 vezes de aumento, utilizando-se um sistema de escores de 0 a 3. Os postos médios foram: P-90 = 23.48; SE PLUS = 31.13; e SBMP = 36.90. Os resultados foram tratados pelos testes de Kruskal-Wallis e Mann-Whitney, que revelaram diferença estatisticamente significante entre os grupos (p ≤ 0,05). P-90 apresentou diferença significante se comparado ao SBMP, exibindo menores escores de penetração do corante. A associação de diferentes sistemas adesivos ao compósito a base de silorano Filtek P-90 influenciou no grau de microinfiltração