Gastón Fuentes Estévez

Hydroxyapatite coating by sol–gel on Ti–6Al–4V alloy as drug carrier

In this study Ti–6Al–4V samples were used as substrates and Ca–P layers were deposited using sol–gel technique and covered by spin-coating. The efficiency of hydroxyapatite (HA) coatings as drug carrier was also evaluated by immersion in gentamicin sulphate solution and the release profiles were obtained by cumulative method of the coating samples. Three non-linear mathematical methods were employed in order to discuss a possible mechanism to lead the drug release. Physical chemical techniques showed the presence of the typical absorption bands of calcium phosphates by infrared spectroscopy while X-ray diffraction peaks matched up with hydroxyapatite patterns. Microstructural techniques (SEM, EDS) help to confirm the hydroxyapatite coating by surface aspect and Ca/P ratio (1.64). The best fitting according statistical results explained each stage of the released profiles and correspond to a mixture of short initial burst effect plus drug dissolution with a specific kinetic and the diffusion of the gentamicin solid particles.

Radiation Sterilization of a Bifunctional Cement Formulation of Hydroxilapatite‐Plaster‐Polymers

ABSTRACT: A sterilization method based on the use of gamma ionizing radiation was applied to a cement formulation of hydroxilapatite, plaster and polymers to be used in bone restorations in dental, aesthetic, and neurological surgery. After the cement was exposed to a dose of 21.5 kGy it reached the sterility assurance level which was necessary for its employment in surgical applications as specified by International Standard ISO ordinate 11137: Radiation Sterilization of Health Care Products. No variation in the initial cement composition or processing parameters, such as working or setting time and molding quality was observed due to sterilization. Its characteristics as a drug delivery system were also not affected. Therefore, radiation sterilization provides a feasible alternative to conventional sterilization methods such as dry/wet heat and ethylene oxide.

Evaluation of acrylic bone cements with single and combined antibiotics: Release behavior and in vitro antibacterial effectiveness

ABSTRACTThis work studied the eluting behavior of Ciprofloxacin, Meropenem and Ceftazidime (and their mixtures) with that of Gentamicin from antibiotic loaded bone cements (ALBCs). In vitro release was followed by UV-Vis for 30 days and a semi-empirical eluting model that considers the processes of dissolution and diffusion was proposed: . The antimicrobial efficacy against P. aeruginosa and S. aureus of the prepared ALBCs was also evaluated. The results showed that the amount of antibiotic released increased when Ciprofloxacin/Meropenem or Ciprofloxacin/Ceftazidime were used and that their antibacterial inhibitory effect against microorganisms tested was improved as a consequence of the synergistic effect.ABSTRACT This work studied the eluting behavior of ciprofloxacin, meropenem, and ceftazidime (and their mixtures) with that of gentamicin from antibiotic-loaded bone cements (ALBCs). In vitro release was followed by UV–Vis for 30 days and a semiempirical eluting model that considers the processes of dissolution and diffusion were proposed: . The antimicrobial efficacy against Pseudomonas aeruginosa and Staphylococcus aureus of the prepared ALBCs was also evaluated. The results showed that the amount of antibiotic released increased when ciprofloxacin/meropenem or ciprofloxacin/ceftazidime was used and that their antibacterial inhibitory effect against microorganisms tested was improved as a consequence of the synergistic effect. GRAPHICAL ABSTRACT

Effectiveness and Therapeutic Safety Using Β-Tricalcium Phosphate in Oral Bone Defects

Aim: To determine the effectiveness and therapeutic safety with β-tricalcium phosphate (Biograft-G®) in oral bone defects. Methods: A Phase III, multicenter, uncontrolled clinical trial (Classification of medical devices), to assess the Biograft-G® Biomaterials Center, University of Havana was made. All the population of the clinical trial was choose from four Cuban provinces and 121 patients was the sample selected for the studies. All the patients gave their consent to participate. The patients included in the study were: ages between 18 and 75 years, both sexes that could be treated surgically. Patients with malignant neoplasms of any location, diabetic patients who were decompensated or difficult to control, immunosuppressed or immunosuppressed, and mentally retarded patients were excluded. Surgeries were performed in patients requiring dental extraction, alveolar ridge reconstruction, periodontal and periapical surgery. The main variable was a clinical and radiographic appearance, evaluated in four periods (7 days, 1, 3 and 6 months) and levels: Success and Failure. Results: An effectiveness of 97.5% for β-tricalcium phosphate (Biograft-G®) was demonstrated. In all the periods of clinical and radiographic evaluation of it showed gradually reabsorption similar to surrounding healthy tissue, until the complete degradation of the biomaterial. It was determined that adverse treatment (infection, delamination of the material, tenderness and pain) events behaved low. Conclusion: It was concluded high effectiveness and safety of treatment with Biograft-G® in complex oral surgery, with minimal and mild adverse events to treatment.

PMMA/Ca2+ bone cements. Hydrolytic properties and bioactivity

Bone cements of poly (methyl methacrylate) (PMMA) have been used for about 40 years to fix artificial prosthesis to bone structure. The aim of this study was to evaluate the absorption, solubility, degradation and bioactivity of novel formulations of PMMA/Ca2+ bone cements. These properties were evaluated using a fractional experimental design. Hydrolytic parameters were determined, from which we found that 7/8 of the formulations for absorption and 6/8 for solubility fulfill the ISO 4049:2000 requirements. The final degradation values ranged between 1 and 5%, except for one of the formulations. Besides, some formulations showed bioactivity after seven days of immersion in SBF solution.