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Uno de los principales retos en la Odontología actual es la regeneración de defectos y atrofias óseas. Estas deficiencias de hueso pueden estar causadas por patología infecciosa, tumoral o traumática, y dificultan o impiden la colocación de implantes osteointegrados. En determinados casos, será necesario regenerar parte del hueso de manera previa o simultánea a la colocación del implante. Para este propósito, la técnica más estudiada y con mayor respaldo científico es la Regeneración Ósea Guiada (ROG). Esta técnica requiere la utilización de una membrana, con el fin de producir una compartimentalización del defecto óseo, impidiendo así la colonización del defecto por estirpes celulares no deseadas, permitiendo, por tanto, la proliferación de osteoblastos y la regeneración del tejido óseo. En el presente trabajo hemos realizado una revisión sistemática de la literatura con metaanálisis para evaluar la eficacia clínica de las membranas existentes cuando se realiza ROG. Se ha determinado que las membranas que con más frecuencia se utilizan para este propósito, son las reabsorbibles de colágeno. Concluimos que la técnica quirúrgica se puede llevar a cabo de manera predecible, pudiendo reducir un defecto horizontal entre 3 y 4,7mm. También sabemos que existen complicaciones en un 8,4% de los casos, siendo la complicación más frecuente es la exposición e infección de la membrana. De las membranas existentes, ninguna satisface completamente las propiedades ideales de estos biomateriales y además, encontramos que la forma de evaluación de las mismas, data del año 2004 (ISO 22803:2004). Por ello, proponemos mediante una revisión narrativa de la literatura una estrategia completa y actual de análisis experimental de este tipo de membranas para ROG. Una membrana de ROG debe ser evaluada con técnicas basadas en nanotecnología desde el punto de vista tribológico, morfométrico y mecánico. Su bioactividad debe ser evaluada mediante cultivos de células de estirpe osteoblástica donde se determine su capacidad de proliferación, diferenciación y mineralización. Estudios experimentales en animal y estudios clínicos controlados y randomizados son siempre necesarios para determinar su efectividad clínica. Con objeto de mejorar este tipo de biomateriales se plantea su funcionalización con doxiciclina y se realiza una revisión sistemática de la literatura donde se revisaron los materiales que con mayor frecuencia se emplean como membranas para ROG, los antibióticos usados para su funcionalización, las distintas técnicas de dopado y su eficacia. Encontramos que existen numerosas combinaciones de funcionalización de antibióticos sobre materiales poliméricos. En todas ellas se consigue efecto antibacteriano, pero solo se han evaluado frente a cultivos de bacterias no específicas y con una única especie, lo que limita su relevancia clínica. Los ensayos en humanos son además limitados y de resultados controvertidos. Finalmente, se propone el diseño y funcionalización con cinc, doxiciclina y dexametasona de membranas poliméricas sintéticas y naturales nanoestructuradas y se realiza un análisis de su interacción con células osteoblásticas. Se determina que la funcionalización de las membranas se puede realizar de modo eficaz y sencillo. La funcionalización más ventajosa desde el punto de vista de proliferación celular es la que se realiza con doxiciclina. En ambos tipos de membranas se consigue una adecuada proliferación celular y mejora de la diferenciación osteoblástica. Se produce una marcada sobreexpresión de genes osteogénicos como BMP-2, ALP, OPG, TGFβ-1 and TGFβ-R1 y se da lugar a una ratio OPG/RANKL más favorable. Los osteoblastos cultivados en membranas poliméricas nanoestructuradas no reabsorbibles y funcionalizadas con doxiciclina presentan mayor expresión de antígenos CD54, CD80, CD86, and HLA-DR, lo que es índice de su posible capacidad inmunomoduladora., Tesis Univ. Granada., MINECO/FEDER MAT2017-85999 PPID2020-114694RB-I00 MCIN/AEI 10.13039/ 501100011033, Beca FPU20/00450

Polymeric membranes are frequently used for bone regeneration in oral and periodontal surgery. Polymers provide adequate mechanical properties (i.e., Young's modulus) to support oral function and also pose some porosity with interconnectivity to permit for cell proliferation and migration. Bacterial contamination of the membrane is an event that may lead to infection at the bone site, hindering the clinical outcomes of the regeneration procedure. Therefore, polymeric membranes have been proposed as carriers for local antibiotic therapy. A literature search was performed for papers, including peer-reviewed publications. Among the different membranes, collagen is the most employed biomaterial. Collagen membranes and expanded polytetrafluoroethylene loaded with tetracyclines, and polycaprolactone with metronidazole are the combinations that have been assayed the most. Antibiotic liberation is produced in two phases. A first burst release is sometimes followed by a sustained liberation lasting from 7 to 28 days. All tested combinations of membranes and antibiotics provoke an antibacterial effect, but most of the time, they were measured against single bacteria cultures and usually non-specific pathogenic bacteria were employed, limiting the clinical relevance of the attained results. The majority of the studies on animal models state a beneficial effect of these antibiotic functionalized membranes, but human clinical assays are scarce and controversial.

Alveolar bone ridge resorption occurred after natural teeth loss and it can restrict the possibility of dental implants placement. The use of bone regenerative procedures is frequently required. The existing evidence regarding the efficacy of horizontal bone ridge augmentation trough guided bone regeneration (GBR) using polymeric membranes was stated. A systematic review and meta-analysis were performed. Electronic and manual literature searches were conducted. Screening process was done using the National Library of Medicine (MEDLINE by PubMed), Embase, and the Cochrane Oral Health. Included articles were randomized controlled trials and observational studies. Weighted means were calculated. Heterogeneity was determined using Higgins (I2). If I2 > 50% a random-effects model was applied. It was found that the mean of horizontal bone gain was 3.95 mm, ranging from 3.19 to 4.70 mm (confidence interval 95%). Heterogeneity is I2 = 99% (confidence interval 95%) and significance of the random-effects model was p < 0.001. The complications rate was 8.4% and membrane exposure was the most frequent. Through this study, we were able to conclude that the existing scientific evidence suggests that GBR using polymeric membranes is a predictable technique for achieving horizontal bone augmentation, thus, permitting a proper further implant placement. Yes

Objective:The purpose of this in vitrostudy was to evaluate the antibacterial effect ofanovel non-resorbable, bioactive polymeric nanostructuredmembrane(NMs), whendoped with zinc, calcium and doxycycline.Methods:A validated in vitrosubgingival biofilm model with six bacterial species (Streptococcus oralis, Actinomyces naeslundii, Veillonela parvula, Fusobacterium nucleatum, Porphyromonas gingivalis andAggregatibacter actinomycetemcomitans)was used. The experimental NMs, with and without beingdoped with doxycycline, calcium and zinc,were placed on hydroxyapatite (HA) discs. As positive control membranes, commercially available dense polytetrafluoroethylene (d-PTFE) membranes were used and,as negative controls,the HA discs without any membrane.The experimental, positive and negative control discs were exposed to a mixed bacterial suspension, at 37ºC under anaerobic conditions,during 12, 24, 48 and 72 hours. The resulting biofilms were analyzed through scanning electron microscopy(SEM),to study their structure,andby quantitative polymerase chain reaction (qPCR),to assess the bacterialload,expressed as colony forming units (CFU) per mL. Differences between experimental and control groups were evaluated with the general linear model and the Bonferroni adjustment. Results:As shown by SEM, all membrane groups,except the NMswith doxycycline,resulted in structured biofilms from 12 to 72 hours. Similarly, only the membranes loaded with doxycycline demonstrated a significant reduction in bacterial load during biofilm development,when compared with the control groups (p, This work was supported by the Ministry of Economy and Competitiveness (and European Regional Development Fund [Project MAT2017-85999-PMINECO/AEI/FEDER/UE] and University of Granada Research and Transfer Program.

The effectiveness of novel polymeric nanoparticles (NPs) application in reducing dentin permeability and facilitating dentin remineralization after endodontic treatment was evaluated. The effect of undoped NPs, zinc, calcium and doxycycline-doped NPs (Zn-NPs, Ca-NPs and D-NPs, respectively) was tested in radicular dentin. A control group without NPs was included. Radicular dentin was assessed for fluid filtration. Dentin remineralization was analyzed by scanning and transmission electron microscopy, energy-dispersive analysis, AFM, Young´s modulus (Ei), Nano DMA, Raman, and X-Ray Diffraction analysis. Ca-NPs and Zn-NPs treated dentin exhibited the lowest microleakage with hermetically sealed dentinal tubules and a zinc-based salt generation onto dentin. Zn-NPs favored crystallinity and promoted the highest Ei and functional remineralization at the apical dentin, generating differences between the values of complex modulus among groups. Ca-NPs produced closure of tubules and porosities at the expense of a relative mineral amorphization, without creating zones of stress concentration. The highest sealing efficacy was obtained in Zn-NPs-treated samples, along with the highest values of Young´s modulus and dentin mineralization. These high values of Ei were obtained by closing voids, cracks, pores and tubules, and by strengthening the root dentin. When using undoped NPs or Ca-NPs, deposition of minerals occurred, but radicular dentin was not mechanically reinforced. Therefore, application of Zn-NPs in endodontically treated teeth previous to the canal filling is encouraged., This work was supported by the Ministry of Economy and Competitiveness and European Regional Development Fund [MAT2017-85999P MINECO/AEI/FEDER/UE].

The objective was to assess doxycycline (Dox) and zinc (Zn) doped nanoparticles' (NPs) potential to protect the resin-dentin interface from cariogenic biofilm. Three groups ofpolymeric NPs were tested: unloaded, loaded with zinc and with doxycycline. NPs were appliedafter dentin etching. The disks were exposed to a cariogenic biofilm challenge in a Drip-FlowReactor during 72 h and 7 d. Half of the specimens were not subjected to biofilm formation butstored 72 h and 7 d. LIVE/DEAD® viability assay, nano-dynamic mechanicalassessment, Raman spectroscopy and field emission electron microscopy (FESEM) analysiswere performed. The measured bacterial death rates, at 7 d were 46% for the control group, 51%for the undoped-NPs, 32% for Dox-NPs, and 87% for Zn-NPs; being total detected bacteriareduced five times in the Dox-NPs group. Zn-NPs treated samples reached, in general, thehighest complex modulus values at the resin-dentin interface over time. Regarding the mineralcontent, Zn-NPs-treated dentin interfaces showed the highest mineralization degree associatedto the phosphate peak and the relative mineral concentration. FESEM images after Zn-NPsapplication permitted to observe remineralization of the etched and non-resin infiltratedcollagen layer, and bacteria were scarcely encountered. The combined antibacterial andremineralizing effects, when Zn-NPs were applied, reduced biofilm formation. Dox-NPs exertedan antibacterial role but did not remineralize the bonded interface. Undoped-NPs did notimprove the properties of the interfaces. Application of Zn-doped NPs during the bondingprocedure is encouraged.

Objective: This study aimed to evaluate the effect of silver loaded nanoparticles (NPs) application on dentin remineralization. Methods: Polymethylmetacrylate-based NPs and silver loaded NPs (Ag-NPs) were applied on demineralized dentin surfaces. Dentin was characterized morphologically by scanning electron microscopy, mechanically probed by a nanoindenter to test nanohardness and Young modulus, and chemically analyzed by Raman spectroscopy after 24 h and 7 d of storage. Untreated surfaces were used as control. Data were submitted to ANOVA and Student-Newman-Keuls multiple comparisons tests (P, This work was supported by the Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (FEDER). Project MAT2017-85999-P MINECO/AEI/FEDER/UE.

The aim of this study was to evaluate the effectiveness of different nanoparticles-based solutions for dentin permeability reduction and to determine the viscoelastic performance of cervical dentin after their application. Four experimental nanoparticle solutions based on zinc, calcium or doxycycline-loaded polymeric nanoparticles (NPs) were applied on citric acid etched dentin, to facilitate the occlusion and the reduction of the fluid flow at the dentinal tubules. After 24 h and 7 d of storage, cervical dentin was evaluated for fluid filtration. Field emission scanning electron microscopy, energy dispersive analysis, AFM and Nano-DMA analysis were also performed. Complex, storage, loss modulus and tan delta (δ) were assessed. Doxycycline-loaded NPs impaired tubule occlusion and fluid flow reduction trough dentin. Tubules were 100% occluded in dentin treated with calcium-loaded NPs or zinc-loaded NPs, analyzed at 7 d. Dentin treated with both zinc-NPs and calcium-NPs attained the highest reduction of dentinal fluid flow. Moreover, when treating dentin with zinc-NPs, complex modulus values attained at intertubular and peritubular dentin were higher than those obtained after applying calcium-NPs. Zinc-NPs are then supposed to fasten active dentin remodeling, with increased maturity and high mechanical properties. Zinc-based nanoparticles are then proposed for effective dentin remineralization and tubular occlusion. Further research to finally prove for clinical benefits in patients with dentin hypersensitivity using Zn-doped nanoparticles is encouraged., This work was supported by the Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (FEDER) [Project MAT2017-85999-P]

Objective: Characterization of novel calcium and zinc loaded electrospun matrices for periodontal regeneration. Materials and Methods: A polymethylmetacrylate-based membrane was calcium or zinc loaded. Matrices were characterized morphologically by atomic force and scanning electron microscopy, and mechanically probed by a nanoindenter. Biomimetic calcium phosphate precipitation on polymeric tissues was assessed. Cell viability tests were performed using oral mucosa fibroblasts. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests or by ANOVA and Student- Newman-Keuls multiple comparisons. Results: Zinc and calcium loading on matrices did not modify their morphology but increased nanomechanical properties and decreased nanoroughness. Precipitation of calcium and phosphate on the matrices surfaces was observed in zinc-loaded specimens. Matrices were found to be non-toxic to cells in all the assays. Calcium and zinc-loaded scaffolds presented a very low cytotoxic effect. Conclusions: Zinc-loaded membranes permit cells viability and promoted mineral precipitation in physiological conditions. Based on the tested nanomechanical properties and scaffold architecture, the proposed membranes may be suitable for cell proliferation. Clinical Relevance: The ability of zinc-loaded matrices to promote precipitation of calcium phosphate deposits, together with their observed non-toxicity and its surface chemistry allowing covalent binding of proteins, may offer new strategies for periodontal regeneration., Project MAT2014-52036-P supported by the Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (FEDER).

The aim of this study was to assess the mechanical and chemical performance of sound and caries-affected dentin (CAD), after Zn-free vs containing amalgam restorations placement and thermocycling. Dentin surfaces were studied by Atomic Force Microscopy (AFM) analysis for surface morphological characterization (including fibril diameter assessment), nano-indentation (to measure nano-hardness-Hi and modulus of Young-Ei), and single point Raman spectroscopy for chemical analysis. Measurements were performed before amalgam placement, after amalgam removal, and after 3 months of thermocycling (100,000cy/5 ºC and 55 ºC). Restorations increased both Hi and Ei at intertubular dentin of CAD. The highest values of Hi were achieved at intertubular dentin after restoring with Zn-containing amalgams. Remineralization of dentin was attributed to the increase of both amorphous and crystalline new mineral, as lower degrees of crystal imperfections in junction with crystal disorders, and improvement in structural stability of collagen were found. Higher presence of minerals were also confirmed after the decrease of fluoridated apatite and the increase of the total water content. Proteoglycans, lipids, and proteins, augmented in both sound and CAD, providing support for the mineral growing. The increase of bands assigned to vibration of carbonate calcium phosphate contributed to a decrease of crystallinity., Project MAT2014-52036-P supported by the Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (FEDER).

This work was funded by the Ministry of Economy and Competitiveness and European Regional Development Fund( MINECO/AEI/FEDER/UE) Project number PID2020-114694RBI00. Funding for open access charge: University of Granada / CBUA., Objective. To investigate the effect of novel polymeric nanoparticles (NPs) doped with melatonin (ML) on nano-hardness, crystallinity and ultrastructure of the formed hydroxyapatite after endodontic treatment. Methods. Undoped-NPs and ML-doped NPs (ML-NPs) were tested at radicular dentin, after 24 h and 6 m. A control group without NPs was included. Radicular cervical and apical dentin surfaces were studied by nano-hardness measurements, X-ray diffraction and transmission electron microscopy. Mean and standard deviation were analyzed by ANOVA and StudentNewman-Keuls multiple comparisons (p < 0.05). Results. Cervical dentin treated with undoped NPs maintained its nano-hardness values after 6 m of storage being [24 h: 0.29 (0.01); 6 m: 0.30 (0.02) GPa], but it decreased at apical dentin [24 h: 0.36 (0.01); 6 m: 0.28 (0.02) GPa]. When ML-NPs were used, nano-hardness was similar over time [24h: 0.31 (0.02); 6 m: 0.28 (0.03) GPa], at apical dentin. Root dentin treated with ML-NPs produced, in general, high crystallinity of new minerals and thicker crystals than those produced in the rest of the groups. After 6 m, crystals became organized in randomly oriented polyhedral, square polygonal block-like apatite or drop-like apatite polycrystalline lattices when ML-NPs were used. Undoped NPs generated poor crystallinity, with preferred orientation of small crystallite and increased microstrain. Significance. New polycrystalline formations encountered in dentin treated with ML-NPs may produce structural dentin stability and high mechanical performance at the root. The decrease of mechanical properties over time in dentin treated without NPs indicates scarce remineralization potential, dentin demineralization and further potential degradation. The amorphous stage may provide high hydroxyapatite solubility and remineralizing activity., Ministry of Economy and Competitiveness and European Regional Development Fund( MINECO/AEI/FEDER/UE) PID2020-114694RB-I00, University of Granada/CBUA