1,544 research outputs found

    Effects of activator treatment - evidence for the occurrence of two different types of reaction

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    A longitudinal cephalometric study was made of 12 boys and 13 girls with Class 11, Division 1 malocclusion treated with activators. The findings were compared with an untreated control group of 24 boys and 15 girls. The children were aged about 9 years at the start of the investigation and they were treated, or observed, for about two years. Possible alterations of mandibular condylar growth were investigated and the results were compared with previously published hypotheses on the mode of action of the activator. Since there were significant differences in the growth increments of control boys and control girls, the sexes were treated statistically as separate groups. Mandibular growth was found to be altered by activator therapy; in the boys growth was increased and redirected posteriorly while in the girls growth was only redirected. The maxilla and the dental arches were differently affected by the treatment. The differences in the observed results are probably explained by variation in the amount of vertical activation of the appliance but the possibility that boys and girls generally react differently could not be excluded. It is also possible that at least some of the differences were due to special growth patterns associated with certain features in the initial cephalometric pattern. There was no indication that modes of appliance action led to the different reactions. The results as a whole support the concept of the activator as an appliance which transduces elastic soft tissue forces to the skeletal and dental unit

    Observations on pulpal response to carbon dioxide laser drilling of dentine in healthy human third molars

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    Preservation of pulpal health is the primary prerequisite for successful application of laser systems in the hard tissue management of vital teeth. The purpose of this study was to investigate the short and long-term pulpal effects to cavity preparations in healthy human teeth using carbon dioxide (CO2) laser. A total of seven, healthy, third molars that were scheduled to be removed due to space problems were used. After the laser drilling, the occlusal cavities were closed temporarily, and the teeth were extracted 7days (n=5) and 3 months (n=2) after the operation. The specimens were fixed, decalcified, subdivided and processed for light and transmission electron microscopy. Seven days postoperatively all the five teeth that had been irradiated with the CO2 laser did not reveal any pathological changes in the pulpo-dentine complex. Three months postoperatively the two teeth that were prepared with the laser showed subtle but distinct apposition of tertiary dentine that was lined with intact odontoblasts. One of the specimens at 3 months revealed the presence of a mild, but very circumscribed, pulpal infiltration of chronic inflammatory cells subjacent to the cavity preparation. The latter is unlikely to be due to a direct effect of the laser irradiation but a possible consequence of microleakage of oral antigens and/or other tissue-irritating molecules through the temporary restoration and the remaining dentine thickness (RDT). Although these preliminary histological results suggest that the CO2 laser under investigation induced only minimal response of the dentine-pulp complex when used as a hard-tissue drilling tool, with specific energy settings, pulse duration within thermal relaxation time and emitting radiations at 9.6μm of wavelength, larger clinical trials involving various types of teeth are necessary to reach definite conclusions for large-scale clinical application of the laser devic

    Abnormal mandibular growth and the condylar cartilage

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    Deviations in the growth of the mandibular condyle can affect both the functional occlusion and the aesthetic appearance of the face. The reasons for these growth deviations are numerous and often entail complex sequences of malfunction at the cellular level. The aim of this review is to summarize recent progress in the understanding of pathological alterations occurring during childhood and adolescence that affect the temporomandibular joint (TMJ) and, hence, result in disorders of mandibular growth. Pathological conditions taken into account are subdivided into (1) congenital malformations with associated growth disorders, (2) primary growth disorders, and (3) acquired diseases or trauma with associated growth disorders. Among the congenital malformations, hemifacial microsomia (HFM) appears to be the principal syndrome entailing severe growth disturbances, whereas growth abnormalities occurring in conjunction with other craniofacial dysplasias seem far less prominent than could be anticipated based on their oftendisfiguring nature. Hemimandibular hyperplasia and elongation undoubtedly constitute the most obscure conditions that are associated with prominent, often unilateral, abnormalities of condylar, and mandibular growth. Finally, disturbances of mandibular growth as a result of juvenile idiopathic arthritits (JIA) and condylar fractures seem to be direct consequences of inflammatory and/or mechanical damage to the condylar cartilag

    Factores que inciden en la repitencia académica en los estudiantes de 2do y 3er año del turno sabatino de la carrera Licenciatura en Fisioterapia del Instituto Politécnico de la Salud, IPS-UNAN, Managua, Agosto-Noviembre 2016

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    Dicha investigación fue realizada en la UNAN- Managua, con el objetivo de analizar los factores que inciden en la repitencia académica de los estudiantes que cursan el 2do y 3er año del turno sabatino de la carrera Lic. Fisioterapia. Es un estudio de carácter cuantitativo así mismo es descriptivo y explicativo. Las técnicas de recolección de información utilizada fueron, la encuesta, elaborada en dos perfiles, una para estudiantes y otra para docentes aplicada a 23 estudiantes de 2do y 3er año de la Lic. Fisioterapia, así como a 4 docentes de la carrera, siendo su finalidad obtener información relevante vinculada a las causas que provocan este fenómeno. Para el análisis de la información se utilizó el programa estadístico SPSS versión 23, el cual tiene la capacidad de trabajar con bases de datos grandes este facilitó el análisis, el cruce de las variables y la elaboración de gráficas. Algunos datos que se lograron identificar, es que predomina el sexo femenino; que dentro de los grupos etarios predominan los jóvenes entre las edades de 17 y 25 años, que la mayoría de estudiantes habitan en el sector urbano y los datos del estado civil predomina la soltería. De las principales causas que generan la repitencia, se identificó, cuentan con ingresos propios, pero el 52.17% no cuentan con alguna alternativa laboral. De los que cuentan con ingresos, tienen carga de terceras personas bajo su responsabilidad, además tienen cargas laborales de tiempo completo y de medio tiempo lo que les provoca inestabilidad académica dado al tiempo limitado con el que cuentan para dedicárselo a los estudios

    Associations Between Online Pornography and Sexual Behavior Among Adolescents: Myth or Reality?

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    This study aimed to compare the sexual behavior of adolescents who were or were not exposed to online pornography, to assess to what extent the willingness of exposure changed these possible associations, and to determine the profiles of youths who were exposed to online pornography. Data were drawn from the 2002 Swiss Multicenter Adolescent Survey on Health, a self-administered cross-sectional, paper and pencil questionnaire. From the 7529 adolescents aged 16-20years, 6054 (3283 males) used the Internet during the previous month and were eligible for our study. Males were divided into three groups (wanted exposure, 29.2%; unwanted exposure, 46.7%; no exposure, 24.1%) whereas females were divided into two groups (exposure, 35.9%; no exposure, 64.1%). The principal outcome measures were demographic characteristics, Internet use parameters and risky sexual behaviors. Risky sexual behaviors were not associated with online pornography exposure in any of the groups, except that males who were exposed (deliberately or not) had higher odds of not having used a condom at last intercourse. Bi/homosexual orientation and Internet use parameters were not associated either. Additionally, males in the wanted exposure group were more likely to be sensation-seekers. On the other hand, exposed girls were more likely to be students, higher sensation-seekers, early maturers, and to have a highly educated father. We conclude that pornography exposure is not associated with risky sexual behaviors and that the willingness of exposure does not seem to have an impact on risky sexual behaviors among adolescent

    Toxoplasma effectors targeting host signaling and transcription

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    Early electron microscopy studies revealed the elaborate cellular features that define the unique adaptations of apicomplexan parasites. Among these were bulbous rhoptry (ROP) organelles and small, dense granules (GRAs), both of which are secreted during invasion of host cells. These early morphological studies were followed by the exploration of the cellular contents of these secretory organelles, revealing them to be comprised of highly divergent protein families with few conserved domains or predicted functions. In parallel, studies on host-pathogen interactions identified many host signaling pathways that were mysteriously altered by infection. It was only with the advent of forward and reverse genetic strategies that the connections between individual parasite effectors and the specific host pathways that they targeted finally became clear. The current repertoire of parasite effectors includes ROP kinases and pseudokinases that are secreted during invasion and that block host immune pathways. Similarly, many secretory GRA proteins alter host gene expression by activating host transcription factors, through modification of chromatin, or by inducing small noncoding RNAs. These effectors highlight novel mechanisms by whichhas learned to harness host signaling to favor intracellular survival and will guide future studies designed to uncover the additional complexity of this intricate host-pathogen interaction

    MRI of the temporo-mandibular joint: which sequence is best suited to assess the cortical bone of the mandibular condyle? A cadaveric study using micro-CT as the standard of reference

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    Objective: To determine the best suited sagittal MRI sequence out of a standard temporo-mandibular joint (TMJ) imaging protocol for the assessment of the cortical bone of the mandibular condyles of cadaveric specimens using micro-CT as the standard of reference. Methods: Sixteen TMJs in 8 human cadaveric heads (mean age, 81years) were examined by MRI. Upon all sagittal sequences, two observers measured the cortical bone thickness (CBT) of the anterior, superior and posterior portions of the mandibular condyles (i.e. objective analysis), and assessed for the presence of cortical bone thinning, erosions or surface irregularities as well as subcortical bone cysts and anterior osteophytes (i.e. subjective analysis). Micro-CT of the condyles was performed to serve as the standard of reference for statistical analysis. Results: Inter-observer agreements for objective (r = 0.83-0.99, P < 0.01) and subjective (κ = 0.67-0.88) analyses were very good. Mean CBT measurements were most accurate, and cortical bone thinning, erosions, surface irregularities and subcortical bone cysts were best depicted on the 3D fast spoiled gradient echo recalled sequence (3D FSPGR). Conclusion: The most reliable MRI sequence to assess the cortical bone of the mandibular condyles on sagittal imaging planes is the 3D FSPGR sequence. Key Points : • MRI may be used to assess the cortical bone of the TMJ. • Depiction of cortical bone is best on 3D FSPGR sequences. • MRI can assess treatment response in patients with TMJ abnormalitie
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