Assessing the parameters modulating optical losses of iron oxide nanoparticles under near infrared irradiation.

Heating mediated by iron oxide nanoparticles subjected to near infrared irradiation has recently gained lots of interest. The high optical loss values reported in combination with the optical technologies already existing in current clinical practices, have made optical heating mediated by iron oxide nanoparticles an attractive choice for treating internal or skin tumors. However, the identification of the relevant parameters and the influence of methodologies for quantifying the optical losses released by iron oxide nanoparticles are not fully clear. Here, we report on a systematic study of different intrinsic (size, shape, crystallinity, and iron oxidation state) and extrinsic (aggregation, concentration, intracellular environment and irradiation conditions) parameters involved in the photothermal conversion of iron oxide nanoparticles under near infrared irradiation. We have probed the temperature increments to determine the specific loss power of iron oxide nanoparticles with different sizes and shapes dispersed in colloidal suspensions or inside live breast cancer cells. Our results underline the relevance of crystal surface defects, aggregation, concentration, magnetite abundance, excitation wavelength and density power on the modulation of the photothermal conversion. Contrary to plasmonic or magnetic losses, no significant influence of nanoparticle size nor shape was observed on the optical losses released by the studied iron oxide nanoparticles. Interestingly, no significant differences of measured temperature increments and specific loss power values were either observed when nanoparticles were inside live cells or in colloidal dispersion. Our findings highlight the advantages of optical heat losses released by iron oxide nanoparticles for therapeutic applications.

Carboxy-Terminal Cementum Protein 1-Derived Peptide 4 (cemp1-p4) Promotes Mineralization through wnt/ß-catenin Signaling in Human Oral Mucosa Stem Cells.

Human cementum protein 1 (CEMP1) is known to induce cementoblast and osteoblast differentiation and alkaline phosphatase (ALP) activity in human periodontal ligament-derived cells in vitro and promotes bone regeneration in vivo. CEMP1's secondary structure analysis shows that it has a random-coiled structure and is considered an Intrinsic Disordered Protein (IDP). CEMP1's short peptide sequences mimic the biological capabilities of CEMP1. However, the role and mechanisms of CEMP1's C-terminal-derived synthetic peptide (CEMP1-p4) in the canonical Wnt/ß-catenin signaling pathway are yet to be described. Here we report that CEMP1-p4 promotes proliferation and differentiation of Human Oral Mucosa Stem Cells (HOMSCs) by activating the Wnt/ß-catenin pathway. CEMP1-p4 stimulation upregulated the expression of ß-catenin and glycogen synthase kinase 3 beta (GSK-3B) and activated the transcription factors TCF1/7 and Lymphoid Enhancer binding Factor 1 (LEF1) at the mRNA and protein levels. We found translocation of ß-catenin to the nucleus in CEMP1-p4-treated cultures. The peptide also penetrates the cell membrane and aggregates around the cell nucleus. Analysis of CEMP1-p4 secondary structure revealed that it has a random-coiled structure. Its biological activities included the induction to nucleate hydroxyapatite crystals. In CEMP1-p4-treated HOMSCs, ALP activity and calcium deposits increased. Expression of Osterix (OSX), Runt-related transcription factor 2 (RUNX2), Integrin binding sialoproptein (IBSP) and osteocalcin (OCN) were upregulated. Altogether, these data show that CEMP1-p4 plays a direct role in the differentiation of HOMSCs to a "mineralizing-like" phenotype by activating the ß-catenin signaling cascade.

Iron-Based Core-Shell Nanowires for Combinatorial Drug Delivery and Photothermal and Magnetic Therapy.

Combining different therapies into a single nanomaterial platform is a promising approach for achieving more efficient, less invasive, and personalized treatments. Here, we report on the development of such a platform by utilizing nanowires with an iron core and iron oxide shell as drug carriers and exploiting their optical and magnetic properties. The iron core has a large magnetization, which provides the foundation for low-power magnetic manipulation and magnetomechanical treatment. The iron oxide shell enables functionalization with doxorubicin through a pH-sensitive linker, providing selective intracellular drug delivery. Combined, the core-shell nanostructure features an enhanced light-matter interaction in the near-infrared region, resulting in a high photothermal conversion efficiency of >80% for effective photothermal treatment. Applied to cancer cells, the collective effect of the three modalities results in an extremely efficient treatment with nearly complete cell death (∼90%). In combination with the possibility of guidance and detection, this platform provides powerful tools for the development of advanced treatments.

Morphological and chemical changes in human deciduous dentin after phosphoric acid, self-etching adhesive and Er: YAG laser conditioning.

The morphological and chemical changes in deciduous dentin produced by different conditioning protocols were evaluated in this in vitro study. Eighty primary dentin samples were divided into eight groups (n = 10): G1, acid etching; G2, self-etching adhesive; G3, G4, Er: YAG laser irradiation at 25.5 and 38.2 J cm-2 , respectively; 10 Hz and spray irrigation. Groups 5, 6, 7, and 8 were irradiated at previous densities, and then phosphoric acid or self-etching adhesive conditioning was applied. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to evaluate chemical and morphological changes. Paired t-test and One-way ANOVA were used for statistical analysis (p ≤ 0.05). All samples showed different morphology with specific characteristics according to the conditioning protocol. Changing element concentration values are expressed in atomic percent (at %). After conditioning, there were statistically significant differences (p ≤ 0.05) for p at% and Ca/P in all groups; highlighting the following additional findings by group: G1, G7, and G8 showed changes in all elements studied, G2 presented a decrease in C at% and increased Ca at%, G3 and G4 exhibited at% changes in C, trace elements and Ca. Furthermore, G5 showed at% changes in O and trace elements; while G6 changes were observed on C at%, O at% and trace elements at%. Dentin morphology and chemical composition varied in accordance with the conditioning protocol, with characteristics specific for each one that could have clinical implications for the retention and bond strength performance of adhesive materials.

Manejo odontológico del paciente con hipoacusia neurosensorial profunda bilateral / Dental management of patients with bilateral profound sensorineural hearing loss

Introducción: la hipoacusia es la disminución de la agudeza auditiva o de la capacidad para captar el sonido; esta puede ser neurosensorial, conductiva o mixta. La hipoacusia neurosensorial resulta de alteraciones en el oído interno, nervio auditivo o en los núcleos auditivos del tronco cerebral. El manejo de estos pacientes requiere disposición, conocimientos y calidez para el correcto desarrollo de la atención estomatológica. Objetivo: reportar el manejo odontológico de un paciente con hipoacusia neurosensorial profunda bilateral. Presentación del caso: paciente femenino de 7 años y 10 meses de edad con diagnóstico de hipoacusia neurosensorial profunda bilateral, quien acude a consulta por presentar dolor. A la inspección física, paciente mesofacial, perfil convexo. Intraoralmente se observan tejidos blandos clínicamente sanos, alteraciones de número y posición, caries moderada e higiene deficiente. Durante la inspección clínica la paciente se mostró poco cooperadora (Frankl II). El plan de tratamiento consistió en prevención, operatoria, ortopedia y cirugía. Para el manejo del paciente se incluyó un lenguaje de señas básico con uso de careta y sin cubreboca, modelado con otros pacientes. Se modificó la técnica decir, mostrar y hacer por mostrar/oler, tocar y hacer. Conclusiones: el odontopediatra debe tener las competencias necesarias para la atención integral de pacientes con capacidades diferentes. El manejo de la conducta y el cuidado multidisciplinario del paciente en edades tempranas es fundamental para el éxito del tratamiento. En el caso clínico que se presenta se resalta la efectividad del manejo conductual modificado, lo cual incrementó la posibilidad de éxito de la rehabilitación dental del paciente, así como de su seguimiento(AU)

Introduction: hearing loss is reduced auditory acuity or a decrease in the ability to perceive sound. It may be sensorineural, conductive or mixed. Sensorineural hearing loss results from alterations in the inner ear, the auditory nerve or the auditory brainstem nuclei. Dental management of these patients requires willingness, knowledge and warmth on the part of the dental practitioner. Objective: report the dental management of a patient with bilateral profound sensorineural hearing loss. Case presentation: a female patient aged 7 years and 10 months diagnosed with bilateral profound sensorineural hearing loss attends consultation for dental pain. At physical inspection, it is observed that the patient is mesofacial with a convex profile. Intraoral examination found clinically healthy soft tissue, tooth alterations in number and position, moderate decay and poor hygiene. During clinical inspection, the patient was uncooperative (Frankl II). Treatment consisted in prevention, restoration, orthopedics and surgery. Management of the patient included use of basic sign language and a mask without the practitioner wearing a facemask, and modeling with other patients. The technique of say, show and do was replaced by show / smell, touch and do. Conclusions: pediatric dentists should have the skills required for the comprehensive care of patients with different capabilities. Behavior management and multidisciplinary care of very young patients is essential for a successful treatment. The clinical case herein presented highlights the effectiveness of modified behavior management, which increased the chances of success in the patient's dental rehabilitation and follow-up(AU)

Chemical and morphological changes in human dentin after Er:YAGlaser irradiation: EDS and SEM analysis.

Sixty samples of human dentin were divided into six groups (n = 10) and were irradiated with Er:YAG laser at 100 mJ-19.9 J/cm(2), 150 mJ-29.8 J/cm(2), 100 mJ-35.3 J/cm(2), 150 mJ-53.0 J/cm(2), 200 mJ-70.7 J/cm(2), and 250 mJ-88.5 J/cm(2), respectively, at 7 Hz under a water spray. The atomic percentages of carbon, oxygen, magnesium, calcium, and phosphorus and the Ca-to-P molar ratio on the dentin were determined by energy dispersive X-ray spectroscopy. The morphological changes were observed using scanning electron microscopy. A paired t-test was used in statistical analysis before and after irradiation, and a one-way ANOVA was performed (P ≤ 0.05). The atomic percent of C tended to decrease in all of the groups after irradiation with statistically significant differences, O and Mg increased with significant differences in all of the groups, and the Ca-to-P molar ratio increased in groups IV, V, and VI, with statistically significant differences between groups II and VI. All the irradiated samples showed morphological changes. Major changes in the chemical composition of dentin were observed in trace elements. A significant increase in the Ca-to-P ratio was observed in the higher energy density groups. Morphological changes included loss of smear layer with exposed dentinal tubules. The changes produced by the different energy densities employed could have clinical implications, additional studies are required to clarify them.

Chemical changes associated with increased acid resistance of Er:YAG laser irradiated enamel.

BACKGROUND: An increase in the acid resistance of dental enamel, as well as morphological and structural changes produced by Er:YAG laser irradiation, has been reported. PURPOSE: To evaluate the chemical changes associated with acid resistance of enamel treated with Er:YAG laser. Methods. Forty-eight enamel samples were divided into 4 groups (n = 12). Group I (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm(2)), 200 mJ (25.5 J/cm(2)), and 300 mJ (38.2 J/cm(2)), respectively. RESULTS: There were significant differences in composition of irradiated groups (with the exception of chlorine) and in the amount of calcium released. CONCLUSIONS: Chemical changes associated with an increase in acid resistance of enamel treated with Er:YAG laser showed a clear postirradiation pattern characterized by a decrease in C at.% and an increase in O, P, and Ca at.% and no changes in Cl at.%. An increased Ca/P ratio after Er:YAG laser irradiation was associated with the use of higher laser energy densities. Chemical changes produced by acid dissolution showed a similar trend among experimental groups. Stable or increased Ca/P ratio after acid dissolution was observed in the irradiated groups, with reduction of Ca released into the acid solution.

Evaluation of self-etching adhesive and Er:YAG laser conditioning on the shear bond strength of orthodontic brackets.

The purpose of this study was to evaluate the shear bond strength, the adhesive remnant index scores, and etch surface of teeth prepared for orthodontic bracket bonding with self-etching primer and Er:YAG laser conditioning. One hundred and twenty bovine incisors were randomly divided into four groups. In Group I (Control), the teeth were conditioned with 35% phosphoric acid for 15 seconds. In Group II the teeth were conditioned with Transbond Plus SEP (5 sec); III and IV were irradiated with the Er:YAG 150 mJ (11.0 J/cm²), 150 mJ (19.1 J/cm²), respectively, at 7-12 Hz with water spray. After surface preparation, upper central incisor stainless steel brackets were bonded with Transbond Plus Color Change Adhesive. The teeth were stored in water at 37°C for 24 hours and shear bond strengths were measured, and adhesive remnant index (ARI) was determined. The conditioned surface was observed under a scanning electron microscope. One-way ANOVA and chi-square test were used. Group I showed the significantly highest values of bond strength with a mean value of 8.2 megapascals (MPa). The lesser amount of adhesive remnant was found in Group III. The results of this study suggest that Er:YAG laser irradiation could not be an option for enamel conditioning.

Morphological and structural changes on human dental enamel after Er:YAG laser irradiation: AFM, SEM, and EDS evaluation.

OBJECTIVE: The purpose of this study was to evaluate, using atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), the morphological and structural changes of the enamel after irradiation with the Er:YAG laser. BACKGROUND DATA: A previous study showed that subablative Er:YAG laser irradiation produced undesirable morphological changes on the enamel surface, such as craters and cracks; however, the enamel acid resistance was not increased. METHODS: Fifty-two samples of human enamel were divided into four groups (n = 13): Group I was the control (no laser irradiation), whereas Groups II, III, and IV were irradiated with the Er:YAG 100 mJ (12.7 J/cm(2)), 100 mJ (7.5 J/cm(2)), and 150 mJ (11 J/cm(2)), respectively, at 10 Hz with water spray. The morphological changes were observed by AFM and SEM. The weight percentages (wt%) of calcium (Ca), phosphorus (P), oxygen (O) and chlorine (Cl) were determined in the resultant craters and their periphery using EDS. Kruskal-Wallis and Mann-Whitney U tests were performed (p ≤ 0.05) to distinguish significant differences among the groups. RESULTS: The AFM images showed cracks with depths between 250 nm and 750 nm for Groups II and IV, respectively, and the widths of these cracks were 5.37 µm and 2.58 µm. The interior of the cracks showed a rough surface. The SEM micrographs revealed morphological changes. Significant differences were detected in Ca, P, and Cl in the crater and its periphery. CONCLUSIONS: AFM observations showed triangular-shaped cracks, whereas craters and cracks were evident by SEM in all irradiated samples. It was not possible to establish a characteristic chemical pattern in the craters.

Saturación venosa central de oxígeno. Su valor en el monitoreo cardiovascular pediátrico / Central venous oxygen saturation. Its importance in pediatric cardiovascular monitoring

Introducción. El gasto cardíaco puede valorarseclínicamente o medirse mediante estudios que presentanlimitaciones de interpretación. La saturaciónvenosa central de oxígeno es un indicadorindirecto del gasto cardíaco. Propósito del estudio:evaluar la utilidad de la saturación venosa centralde oxígeno en el monitoreo posoperatorio de cardiocirugíapediátrica.Población, material y métodos. Estudio observacionalretrospectivo de 70 pacientes operados entre1998-2001. Al ingreso a unidad de cuidados intensivosse clasificaron en 4 grupos según su gastocardíaco interpretado por frecuencia cardíaca, presiónarterial, diuresis, pulso y temperatura: estables(I), bajo gasto leve (II), moderado (III) y severo(IV). Se instituyó tratamiento de acuerdo con lagravedad. Se obtuvieron gases arteriales y venososregularmente.Resultados. Edades: 18 meses(5,5 menos 29,2). Los tiemposde circulación extracorpórea y de clampeo aórticofueron más prolongados para los grupos II, IIIy IV respecto del I (p igual 0,03). Las variables a las 24horas que mostraron diferencias significativas fueron:saturación venosa central de oxígeno (I: 73,8 por ciento;II: 69 por ciento; III: 63 por ciento; IV: 59 por ciento) (p mayor 0,001; mayor 0,001 y 0,03 al comparar I menos II, II menos III, III menos IV); temperatura y frecuenciacardíaca mayores en grupos II, III y IV respectodel I (p igual 0,008 y mayor 0,001 respectivamente); dosis de dopamina, adrenalina y milrinona más elevadas enlos grupos de mayor gravedad. No hubo diferenciassignificativas respecto de hematócrito, saturaciónarterial de oxígeno ni presión arterial media.Conclusión. Luego de 24 horas de posoperatorio,los valores más bajos de saturación venosa centralde oxígeno en los grupos III y IV nos indicarían unaalteración de la oxigenación tisular como expresiónde bajo gasto cardíaco

Tratamiento ortodóntico de caninos superiores bilaterales retenidos / Orthodontic treatment of bilateral impacted upper canines

El propósito de este estudio es discutir el tratamiento de un paciente con retención bilateral de caninos superiores y reabsorción radicular de los dientes adyacentes. Se muestran los problemas asociados con los caninos superiores retenidos y las intervenciones biomecánicas utilizadas en el tratamiento de ortodoncia